Appendix A Glossary

Appendix A Glossary

Only brief definitions are given to provide a quicklook reference for the reader with re3ard to terminology. Bold face type within a definition refers to a subject-related entry. 2031) 032) 2033)

Aberration. Geometrical errors in imagery whereby a perfect image is not formed. Typical aberrations include spherical aberration, astigmatism, coma, and chromatic aberrations. Lens bendings, locations, powers, materials, and increasing the number of lenses and aperture stop positions are all used to minimize aberrations.

Absorption band. A range of wavelengths, or frequencies, in the electromagnetic spectrum within which radiant energy is absorbed by a substance (gas, liquid or solid). In the gaseous phase, absorption lines are much narrower than in liquids or solids. In a polyatomic gas, an absorption band is actually composed of discrete absorption lines which appear to overlap. Each line is associated with a particular mode of vibration and rotation induced in a gas molecule by incident radiation. Examples:

• Ozone (03) has several absorption bands. They are: a) the Hartley bands (2000-3000 A in UV with max absorption at 2550 A); b) the Huggins bands (w~ak absorption between 3200-3600 A); c) the Chappuis bands (weak and diffuse at 4500 A and at 6500 A in VIS); d) IR bands at 4.7, 9.6, and 14.1!-lm.

• Molecular oxygen (02) also has several absorption bands. They are: a) Hopefield bands (between 670 and 1000 A in UV); b) diffuse between 1019 and 1300 A (UV); c) the Schumann-Runge colltinuum (between 1350-1760 A); d) Schumanp.-Runge bands (between 1760 - 1926 A); e) the Herzberg bands (between 2400-2600 A_); f) the atmospheric bands (between 5380-7710 A, VIS); g) IR at about 11-1m ( = 104 A).

Absorptivity. Ratio of the absorbed to the incident electromagnetic radiation on a surface.

Accuracy. Refers to an estimate of how well a certain parameter or measurement is known; it is a measure of the absolute truth of a measurement requiring absolute (traceable) standards. Accuracy is a quality that characterizes the ability of a measuring instrument to give indications equivalent to the 'true value' of the quantity measured. The quantitative expression of accuracy may also be given in terms of uncertainty. The actual or 'true value' of a quantity cannot be determined; it can only be said to exist within tolerance limits of a measured value. The measurement error is the algebraic difference between the measured (or indicated) value and the true value. Hence, accuracy is by its very nature only an estimation of the true value, taking into account all aspects of measurement.

Acid rain. Rain that is more acid than normal because the raindrops contain dissolved acid gases and/or dust particles (aerosols) from the atmosphere. The principal gases responsible for increased acidity are oxides of sulfur and nitrogen. Generally, rain with a pH below 4.5 is considered environmentally harmful.

Actinometer. A generic term for any instrument used to measure the intensity of radiant energy, in particular that of the sun.

Active sensor. A sensor having its own source of EMR (Electromagnetic Radiation); it transmits a series of signals to the target and detects the echo. A SAR instrument, a lidar, a radar altimeter, etc., are examples of active sensors.

Actuators. Refer to a class of on-board devices or techniques employed in particular for attitude control. Some examples are: reaction wheels, momentum wheel, magnetorquer coil/

2031) Portions of this glossary are taken from: "Glossary and list of Acronyms/Abbreviations," Earth Observation System (EOS), July 1992, Courtesy of EOS Project Science Office (V. V. Salomonson), GSFC, Greenbelt, MD.

2032) Jeanne Hopkins, "Glossary of Astronomy and Astrophysics," The University of Chicago Press, Second Edition, 1985

2033) R. J. Gurney, J. L. Foster, C. I. Parkinson (editors), ''Atlas of satellite observations related to global change," Cambridge University Press, 1993

1314 Appendix A: Glossary

rod, permanent magnets, gravity-gradient boom, nutation damper, control moment gyros, cold gas thrusters, solid thrusters, ion thrusters, mono- or hi-propellant engine, etc.

Adaptive optics. A technique which tries to compensate for the atmospheric degradation of the incoming signal of optical imaging systems. However, the compensations achieved, regardless of method, are never "perfect." The following approaches are in use:

An on-line adaptive optics system (hardware solution). In this version, the adaptive optics system is capable of compensating for the distortion of electromagnetic radiation as it passes through the turbulent atmosphere and the optical system. Elements of an adaptive optical system are a high-speed wavefront sensor (sensing the turbulence-induced aberrations), a flexible mirror system whose surface can be electronically controlled to correct for aberrations, and a computer controller that converts the wavefront measurements into deformable mirror commands. - More economic solutions are suggested by the use of LCPM (Liquid Crystal Phase Modulator) to deform the mirror, and by the use of the pupil masking technique. 2034) 2035)

A post facto approach (software solution), where the data are acquired by an imaging instrument and processed off-line with suitable iterative algorithms to increase the overall resolution obtained by the optics system. Speckle imaging is an example of such a technique. 2036)

A hybrid approach using an adaptive optics system in combination with post facto processing.

Advection. Refers to a change in property of a moving air parcel from one region to another (say, from a warm region to a cool region, thereby changing its temperature). Commonly, advection is divided into horizontal and vertical components; it differs from convection only in scale. Convection is transport by random thermally induced currents, whereas advection is transport by steady vertical currents.

Aerosol. Aerosols are a suspension affine (solid or liquid) particles such as dust, smoke particles, water droplets, etc. in the atmosphere. The smallest aerosols are the atoms of the various atmospheric gases. The range of sizes varies from a few nanometers (molecules) to tens of micrometers (wind-driven sand). Some aerosols (sea salt and haze) occur naturally and some (smoke) are man-made (anthropogenic). The ocean is a significant source of natural tropospheric aerosols. Once in the atmosphere, aerosols may be transported away from their place of origin, sometimes over great distances. -Aerosols can directly and indirectly affect the radiation budget of the atmosphere. Their direct radiative effect is due to their scattering, absorption, and emission properties. Their indirect effect is a result of their ability to act as condensation nuclei in the formation of clouds. Both tropospheric and stratospheric aerosols play an important role in global climate change.

Airglow. A nighttime glow from the upper atmosphere, occurring over middle and low altitudes, due to the emission of light from various atoms, molecules, and ions.

Albedo. The fraction of the total solar radiation incident on a body (or a natural surface such as the ground, ice, snow, water, clouds, etc.) that is reflected by it (commonly expressed as a percentage, see also planetary albedo). Measured albedo information may be applied to cloud analysis, it may also serve in calculations of inherent contrast between targets and background. By definition, white surfaces (i.e. an all reflective Lambert surface) have albedos close to 1, black surfaces have albedos close to zero.

Aliasing. A term in data processing referring to two or more distinctly different signals having identical sample values.

2034)S. R. Restaino, D. M. Payne, ''Adaptive Optics on a shoe string," SPIE Vol. 3494, 1998, pp. 152-160 2035) D. Dayton, S. Browne, J. Gonglewski, "Control Loop Analysis for a Nematic Liquid Crystal Spatial Light Modula

tor Used in an Adaptive Optics System," SPIE Vol. 3494, 1998, pp. 161-160-167 2036)1. C. Christou, et al., "Physically Constrained Iterative Deconvolution of Adaptive Optics Images," SPIE Vol.

3494, 1998, pp. 161-175-190, Proceedings of the SPIE EUROPTO Series, Sept. 23-24, 1998, Barcelona, Spain

Appendix A: Glossary 1315

Altimetry. Altimetry can be described as run-of-time distance measurements taken from a vertically tracking satellite to the geoid. A spaceborne radar altimeter maps the sea surface, which is complex, but which largely conforms to the equipotential surface known as the geoid. The ocean surface departs significantly (at the meter level) from the geoid - this departure is of great interest to the science community (oceanographers, meteorologists, geophysicists, etc.) for it reflects the global circulation patterns and also, in the form of tides and changes in sea level, fundamental climatic and solid Earth phenomena. Furthermore, altimetry provides approximate estimates of the geoid itself, in the form of a mean surface obtained by averaging measurements taken over many satellite passes over the same locations. More detailed explanations on altimetry are given below.

A radar altimeter on-board a satellite permanently transmits signals at high frequency to the Earth's surface, and receives the echo from the sea surface. This is analyzed to derive a precise measurement of the round-trip time between the satellite and the sea surface. By averaging the estimates, say, over a second, this produces a very accurate measurement of the satellite-to-ocean range. However, as electromagnetic waves travel through the atmosphere, they can be decelerated (by water vapor) or accelerated (by ionization). Once these phenomena are corrected for, the final rangeR is estimated within 2 em. 2037)

• Satellite orbit: The ultimate aim is to measure sea level relative to a terrestrial reference frame. This requires independent measurements (accurate tracking) of the satellite orbital trajectory, i.e. exact latitude, longitude and altitude coordinates. The critical orbital parameters for satellite altimetry are altitude, inclination and period.

• Sea surface height (SSH): SSH is the range at a given instant from the sea surface to a reference ellipsoid. SSH is simply the difference between the satellite height (S) and the altimetric range (R): SSH =S-R. The SSH value takes account of such effects as:

The sea surface height which would exist without any disturbances (wind, currents, tides, etc.). This surface, called the geoid, is due to gravity variations around the world, which are in turn due to major mass and density differences on the sea-floor. For example, a denser rock zone on the sea-floor may deform the sea level in the order of tens of meters; this is visible as a hill on the geoid. The ocean circulation, or dynamic topography. The ocean circulation, which comprises a permanent stationary component (permanent circulation linked to Earth's rotation, permanent winds, etc.) and a highly variable component (due to wind, tides, seasonal variations, etc.). The mean effect is on the order of one meter.

Amplitude modulation (AM). The baseband signal is caused to vary the amplitude of the carrier wave to create the wanted information content.

Analog data. Data represented in continuous form, as contrasted with digital data having discrete values.

Angstrom (A, after A. J. Angstrom, a Swedish physicist). A unit of length used in the measurement of shor~ w~velengths (X-rays, gamma rays, etc.) and in the measurement of molecular and atomiC dmmeters. 1 A = w-10 m or w-4 ftm.

Antenna. A sender and receiver system of electromagnetic radiation (in remote sensing terminology the antenna may be part of the sensing instrument, or may be regarded as a coupling device between the target and the sensing instrument). The term antenna refers a) to that part of a transmitting system that converts electrical energy to electromagnetic waves; and conversely b) to that part of a receiving system that converts electromagnetic waves to electrical energy (current) in the receiver (a duplexer automatically switches the antenna from a transmitting function into a receiving function). Physically, an antenna consists of metal surfaces that provide conducting paths for oscillating electric currents and charges. The radiated power of an antenna depends on the shape and size of its geometric contour and on the amplitude and frequency of its oscillation. Some antenna designs:

2037) http://www-projet.cnes.fr:8170/HTML/information/frames/general/si temap _ uk.html


• Dielectric rod antenna. An antenna consisting of a dielectric cylinder that is partially inside a circular waveguide (pipe). It is possible to have an electric field applied to this device- no currents flow through it- although energy passes from one end to the other, thereby generating electromagnetic waves.

Dipole antenna. A thin metal cylinder or wire excited by an alternating current generator at its center so that the ends are oppositely charged. -A dipole antenna is a form of open circuit in which the current oscillates between the ends of the conductor. A dipole antenna may also be a type of array consisting of a system of dipoles. A dipole antenna differs from a dish antenna in that it consists of many separate antennas that collect energy by feeding all their weak individual signals into one common receiving set.

Helix antenna. A helical wire wound with a circumference of about one wavelength and a pitch of 1!4 wavelength over a ground plane with a 1 wavelength minimum diameter.

• Lens antenna. Several types are in use: a) dielectric lens- the aperture of the antenna is equal to the projection of the rim shape; b) artificial dielectrics; c) strip antenna -metal strips are used as waveguides to increase the phase velocity by acting as parallel-plate waveguides.

Loop antenna. The current circulates around or oscillates within the closed loop. The most important application of the loop antenna is reception. The shielded loop antenna is useful as a probe for measuring the magnetic field.

• Microstrip patch antenna. A printed circuit antenna consisting of a radiating patch supported by a dielectric layer over a ground plane.

Monopole antenna. A thin metal cylinder or wire erected vertically over a conducting plane and excited by an alternating current generator connected between the base of the cylinder and the conducting plane.

• Pencil beam antenna. An antenna whose radiation pattern consists of a single main lobe with narrow principal plane beamwidths and side lobes having relatively low levels.

Phased-array antenna. Phased arrays are inherently random-access devices consisting of multiple antenna elements (fixed dipoles) which are fed coherently and use variable phase- or time-delay control at each element to scan a beam to given angles. Arrays are sometimes used in place of fixed aperture antennas (e.g. reflectors or lenses) because the array arrangement allows more precise control of the radiation pattern (lower sidelobes). The primary reason for using arrays is to produce a directive beam that can be scanned (repositioned) electronically in two dimensions without any mechanical movement (see also Phased-array Technology).

Stick antenna. Also referred to as a fan-beam antenna, it produces a major lobe whose transverse cross section has a large ratio of major to minor dimensions.

Slot antenna. A slot in a metal sheet with dimensions J../2 in length and width w (w<< /..) provides a means for achieving efficient directional energy radiation and reception. The radiation leaving the slot antenna is polarized in the direction normal to the major slot dimension (if the slot is horizontal, then the polarization is vertical, and vice versa). Array arrangements of slots permit the radiation of higher energies and consequently the illumination of larger target areas.

Antenna reflectors. A reflector antenna is a large-aperture (gain) directional antenna. A parabolic reflector (mirror) has the property of transforming rays emerging radially from a point source at its focus into a bundle of parallel rays. The reflected parallel rays are all in phase in any plane perpendicular to the axis of the parabola. The laws of optics apply with respect to the radiation geometries and projections (focusing, bundling, redirection of energy, diffraction effects, etc.). Characteristic parameters of a reflector antenna are a func-


tion of the properties ofthe feed and the ratio ofthe reflector's focal length (F) to the diameter (d) of its circular aperture.

Reflector antennas are widely used in the microwave range of the electromagnetic spectrum in the fields of remote sensing, telecommunication, and radio astronomy. Reflectors are inherently broadband instruments; the bandwidth and polarization are determined by the feed antenna. Reflector examples: paraboloidal, parabolic cylinder, dual (Cassegrain, Gregorian), offset-fed, corner, dichroic.

• Cassegrain dual-reflector antenna (telescope). N. Cassegrain, a French scientist, proposed the design in 1672. The basic properties of the Cassegrain dual-reflector are determined from the principles of ray optics. A small convex hyperboloidal subreflector is placed between the point source feed and the prime focus of the parabolic dish. Rays from the feed are transformed by the subreflector into rays that appear to be emerging from the paraboloid focus. The rays reflect from the parabolic reflector parallel to its axis.

Offset aperture reflectors. The blocking of portions of the aperture of a reflector antenna by its feed, supporting structures, or by the subreflector generally degrades the radiation distribution. Hence, high-performance systems employ offset-fed antennas to eliminate the effects of aperture blocking.

• Horn antenna. A horn is an aperture antenna fed from a waveguide mode in an expanded waveguide. The bandwidth is determined by the feed waveguide.

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Figure 418: Some antenna geometries

Ray paths in a horn without dielectric lens .....

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• Dichroic reflector. The term dichroic (chros = color in Greek) implies selective absorption in crystals of electromagnetic radiation vibrating in different planes. - Refers to frequency-selective surfaces designed to exhibit different ratio-frequency properties. In its simplest form, a dichroic surface is virtually perfectly reflecting at one fre-


quency and virtually transparent at another. The most common application of dichroic reflectors has been as subreflectors in Cassegrain antenna systems. Besides reflectors the dichroic principle is also applied to beamsplitters and filters.

Antenna retroreflector. Retroreflection is defined as radiation that is returned in angular directions which are very close to those angular directions from which it came. This (incoming/outgoing) property is maintained over wide variations of the incident radiation. Retroreflector devices come in a variety of forms and have many uses. In remote sensing, a retroreflector uses total internal reflection from three mutually perpendicular surfaces. This kind of retroreflector is usually called a 'corner cube retroreflector'. A corner cube reflector is normally used for radar measurements having a known radar cross section.

Antenna aperture. Surface area (size) of a reflector or horn that is illuminated by the outgoing and/or incoming radiation.

Antenna bandwidth. Range of frequencies within which the performance of an antenna, with respect to some characteristic, conforms to a specified standard. There are many different types of bandwidths, including gain, VSWR (Voltage Standing Wave Ratio), and polarization. For example, a typical bandwidth specification might be: The antenna gain with isotropic must be > 10 dB ± 10 MHz from a center frequency of 2090.0 MHz.

Antenna beamwidth. A planar cut through the radiation pattern containing the direction of the maximum of a lobe, the angle between the two directions in which the radiation intensity is one-half the maximum value and one tenth the maximum value, or in which zero is defined to be the half-power (3 dB), tenth-power (10 dB), or null beamwidth.

Antenna depression angle. The angle between the local horizontal and the center line of the antenna beam pointing at the target.

Antenna directivity. Directivity is a measure of the concentration of radiation in the direction of the maximum. It is the ratio of the radiation intensity in a given direction from the antenna to the radiation intensity averaged over all directions.

Antenna feed. The device in an antenna system that transmits or receives energy to or from the antenna aperture and the radio system.

Antenna footprint. Instantaneous projection of a directional antenna beam illumination on a surface.

Antenna gain. Ratio of the transmitted radiation intensity in a given direction to the radiation intensity that would be received if the power accepted by the antenna were radiated isotropically. In this context, 'peak antenna gain' refers to the maximum radiated intensity expressed as a ratio to the radiation power intensity of a hypothetical isotropic antenna fed with the same transmitting power.

Antenna- intermediate frequency (IF). In microwave systems, a frequency that is common to all channels at which amplification takes place, interconnections are made, and/or automatic gain is adjusted.

Antenna- isotropic. A theoretical antenna of infinitesimal size in which it is assumed that all of the energy is radiated (point source). This concept serves as a reference basis for other antennas of finite dimensions.

Antenna noise temperature. Refers to the increase of the receiver input noise temperature of an antenna system.

Antenna polarization. Spatial orientation of the electric/magnetic field radiated by an antenna. The vector electric/magnetic fields of free space traveling waves are perpendicular to


the direction of travel. Polarization describes how fields behave in time and space. For example, a "circularly polarized" wave can be thought of as having the electric field rotating about the direction of travel. The direction of the filed rotates one turn per period of the wave. A "linearly polarized" wave radiated from an antenna into a specific direction has the electric field direction fixed with time- the only variations are in the instantaneous magnitudes of the electric/magnetic fields.

Antenna scanning techniques.2038) For SAR observations the antenna beam casts an elliptical footprint on the ground with an effective rectangular aperture antenna of typical size 10m (along-track) and 3m (across track).

• Electronic scanning. Defines a method of positioning an electromagnetic beam in space or scanning across a target surface by electronic means. The antenna aperture remains fixed; no mechanical mechanism is involved in the scanning process.

Phase scanning (moved the beam by controlling the phase of the antenna illumination, using phase shifters or delay lines - see also Phased-array technology) Frequency scanning (moves the beam by changing the carrier frequency of the transmitter and receiver) Electronic feed switching

Mechanical scanning. Defines a method of positioning an electromagnetic beam in space by mechanical rotation or angular positioning of the radiating aperture of the antenna system.

• Electronic/mechanical scanning. A hybrid method that employs electronic scanning in one dimension, say in elevation, and mechanical scanning in azimuth.

Antenna sidelobes. Undesired directions in which a directive antenna also receives or radiates power. Sidelobes are generally much weaker than the mean beam in the desired direction.

Antenna waveguide. Usually a hollow metal structure (pipe or other profile) intended to guide or to conduct along its path an electromagnetic wave in a given microwave range (a waveguide is usually attached to a horn; it may also directly serve as a feed for a reflector). The internal dimensions of a waveguide are related to the transmission efficiency of specific frequencies. The cutoff frequency refers to that frequency below which a particular waveguide cannot satisfactorily transmit the wave.

Antenna waveguide modes. Refer to the wave propagation distribution patterns that may exist within a waveguide. They depend on the shape and size of the waveguide with respect to the length of the wave traversing the guide. Each mode has a specific topology, velocity, and energy distribution along and across the guide cross section. The cross section of the waveguide may be square, rectangular, circular, or elliptical.

Anthropogenic gases.'Human-induced' gases emitted into the atmosphere and interacting with the environment. In a wider sense the term refers to all gases emitted as a result of human activities (e.g., chlorofluorocarbons from technical combustion processes, carbon dioxide and methane from livestock farms, rice paddies, biomass burning, etc.).

Aperture. Refers to the maximum diameter of a radiation beam that can pass through a sysc tern (either an optical lens or mirror system or an antenna system}on a telescope or satelc lite. The radiation-gathering power of such a system is proportional to the square of the diameter (or aperture) of the lens (mirror or antenna). Hence, sensors with wider apertures are able to capture more information. Apertures are used to restrict the field ofview.(FOV) of the responsive element (such as a detector). This is often done to reduce noise (cooled detectors are photon-noise limited) from extraneous sources.

2038) P. J. Kahrilas, "Electronic Scanning Radar Systems, Design and Architecture," in 'Practical Phased"Array Antenna Systems,' E. Brookner, Editor, Artech House, Boston, MA


Aperture stop. Location within a lens system where the principle ray passes through and crosses the optical axis. The presence of a mechanical limiting aperture (hole, slot, etc.) typically creates a limiting size.

Aperture synthesis. A technique (pioneered in radio astronomy) of generating high spatial resolution images by dividing the collection area of a telescope (or antenna) into smaller apertures spread out in a pattern covering several baselines. In microwave radiometry the concept employs an interferometric technique in which the product from antenna pairs is sampled as a function of pair spacing. Substantial reductions in the antenna aperture needed for a given spatial resolution can be achieved with this technique. However, the performance leap in resolution must be paid for with higher requirements for instrument precision sensing and stabilization. ESTAR (P.87) and MIRAS (P.132) are examples of airborne synthetic aperture microwave radiometers (both instruments operate in L-band).

Apodizinglunapodizing.2039) The terms are used in the context of data processing in a FTS (Fourier Transform Spectrometer). The actuallineshape of a FTS interferogram is close to (sin x)/x, which is a function with intense side-lobes (also referred to as "feet"). This is the shape that the spectrum of an intrinsically sharp line (e.g. a laser line) would have if the spectrum were untreated, or "unapodized"; to apodize means literally (Greek) "to cut off the feet". Apodizing consists of treating the spectrum to reduce the sidelobes at the expense of degraded resolution (usually by a factor of about two). Apodizing can be done either by tapering the interferogram prior to transforming, or by algebraically filtering the spectrum after transforming.204'0)

Area Array Camera. Refers to a solid-state imaging device (CCD technology) with an array (rows and columns) of pixels producing a 2-D image. The Area Array Camera is also referred to as Matrix Array Camera.

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Figure 419: Sample illustration of an apodized and an unapodized radiation curve

2039) Typical sources observed by a spacebome or airborne FTS are extended such that (due to FOV) the rays through the interferometer are not collimated, leading to side lobes.

2040) Courtesy of K. C. Chance of the Harvard-Smithsonian Astrophysical Observatory, Cambridge MA


Astigmatism. Refers to an aberration in which the light in one plane (for instance the plane of the paper) focuses at a different location from light in the orthogonal plane.

Atmosphere. The envelope of gases surrounding the Earth and bound to it by the Earth's gravitational attraction. Studies of the chemical and radiative properties, dynamic motions, and physical processes of the Earth-atmosphere system constitute the field of meteorology.

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Figure 420: Atmospheric transmittance and radiance for UV to TIR regions

Atmospheric absorption. A process whereby some or all of the energy of electromagnetic radiation is transferred to the constituents of the atmosphere. Absorption by atmospheric gases is dominated by that of water vapor (HzO), carbon dioxide (COz), and ozone (03)

with smaller contributions from methane (CH4), carbon monoxide (CO), and other trace gases. Water vapor is rather variable across the Earth's surface (location) as well as throughout the atmosphere (altitude). COz and CH4 are essentially uniformly mixed in the atmosphere, hence predictable in their effects (see also Absorption bands).- The sum effect of absorption results in atmospheric opaqueness in many spectral regions as illustrated in Figure 420. Hence, observational techniques must blc tailored to utilize those atmospheric windows through which the surface can be viewed. 041 )

Atmospheric attenuation. A process whereby some or all of the energy of electromagnetic radiation is absorbed and/or scattered when passing through the atmosphere. The amount of radiant energy that the atmosphere either removes or adds to that emitted or reflected from the Earth's surface depends on:

The constituents of the atmosphere The path length of radiation (a function of geometry of the source, surface, and sensor) The reflectance of the surface surrounding scene or target area

Atmospheric boundary layer (also referred to as Planetary boundary layer, PBL). This boundary layer includes the bottom part of the atmosphere within which the energy exchange processes (between the Earth's surface and the atmosphere) occur mainly through vertical transport mechanisms of momentum and heat (production of wind shear turbulence plus convective heat turbulence). The whole PBL is heated by convection. Temperature gradients are strongest near the surface, because there convective 'eddies' are relatively small and inefficient in carrying heat upward. The thickness of the daytime PBL is typically in the order of a kilometer; however, it may be three times as high with strong heating. The PBL may also be limited by a top inversion. On a clear day the whole PBL is turbulent; it increases rapidly in the morning and only very slowly after the time of maximum heating, until it decreases to a minimum during the night (sensitivity to diurnal cycle).

2041)A F. Goetz, J_ B. Wellman, W L. Barnes, "Optical Remote Sensing of thy Earth," Proceedings of the IEEE, Vol. 73, No.6, June 1985, pp. 950-969


Atmospheric correction. A problem with spaceborne surface observations is that a large portion of the received signal (about 80%) originates in the atmosphere. Much of this atmospheric signal is due to Rayleigh (or molecular) scattering, primarily from stratospheric ozone. Corrections attributed to Rayleigh scattering are normally estimated taking into account the geometry of a particular scene as well as the extraterrestrial solar radiation, ozone concentration, and atmospheric pressure. Aerosol scattering, primarily encountered in the marine boundary layer, represents another variable in the signal estimation. Since it is not possible to make direct measurements of these aerosols and their contribution to atmospheric optical properties, the remote-sensing community has relied on an indirect approach. The ocean is assumed as largely "black" in the VNIR portion of the spectrum; any radiance measured in this spectral region is assumed to originate in the atmosphere. The spectral dependence of aerosol scattering is in this manner propagated into the UV and VIS portion of the spectrum. Atmospheric correction algorithms try to account for of all the various signal influences in their processing schemes.

Atmospheric refraction. As a signal (electromagnetic radiation) traverses the atmosphere, it experiences propagation delay and bending due to the variable characteristics of the medium through which it is passing. The Earth's ionosphere introduces significant systematic perturbations on all microwave tracking data. At lowerfrequencies (150 MHz) daytime ionospheric biases can easily reach several kilometers in range, several meters per second in range rate, and up to two or three milliradians in position. Since most of the effects decrease as the inverse square offrequency, modern radiometric systems track at dual and well separated higher frequencies. As a signal traverses the troposphere it experiences a varying refractive index resulting primarily from spatial variations in atmospheric pressure, temperature and humidity. For radiometric technologies, variations in water vapor content is of chief concern. Optical signals have a much weaker dependence on water vapor. The varying refractive index influences the propagating signal in several ways. For optical signals, the most important effect is the varying group velocity where the pulse speeds up as it travels from the ground station to low pressure regions at higher altitudes. This change is a consequence of Snell's law of refraction, which predicts the bending and speed of a light ray as it moves through atmospheric layers with differing refractive indices. 2042)

Atmospheric sciences. Study of the dynamics and structure of the Earth's atmosphere. There are three main areas:

Meteorology. Primary concern is short-term weather variations in the lower regions of the atmosphere, in particular the troposphere.

Climatology. Primary concern is long-term weather conditions on a global scale.

Aeronomy. Involves research of the atmospheric regions above the lower stratosphere, dealing with such phenomena as ionospheric physics, photochemical processes of the upper atmosphere, aurorae, magnetospheric storms, etc.

Atmospheric window. Spectral bands for which atmospheric attenuation is relatively low (i.e., the bands for which the atmosphere presents minimal interference).

Aurora. Light radiated by ions in the Earth's upper atmosphere, mainly near the geomagnetic poles, stimulated by bombardment of energetically charged particles ofthe solar wind. Aurorae appear about two days after a solar flare and reach their peak about two years after a sunspot maximum. The northern aurora is also referred to as the 'aurora borealis' while the southern aurora is also called 'aurora australis.' 2043) For many centuries the aurora was referred to as the "northern lights" because it is a polar phenomenon and lies to the north when viewed from Europe. An aurora is a visible man-

2042) Ivan I. Mueller, S. Zerbini, "The Interdisciplinary Role of Space Geodesy," Lecture Notes in Earth Sciences, Spnnger Verlag, 1989, p. 187

2043) L. J. Paxton, C.-I. Meng, "Auroral Imaging and Space-Based Optical Remote Sensing," Johns Hopkins APL Technical Digest, Vol. 20, No 4, 1999, pp. 556-569


ifestation of "space weather" - the highly variable interaction between the sun and the Earth's magnetosphere, upper atmosphere, and ionosphere. The aurora is visible because of interaction of electrons and protons that are accelerated along the Earth's magnetic field lines from the magnetosphere (the cavity in the solar wind created by the Earth's magnetic field) into the Earth's atmosphere, where they undergo collisions with the background gas.

Auroral oval. Refers to the approximately circular band in the northern or southern hemisphere where aurora are most intense. The near-midnight portion of the oval, where some of the brightest emissions occur, is located about ±65° latitude. The mean diameter of the oval is about 4000 km.

Azimuth plane (direction). Observation by an instrument in the along-track direction, i.e. in the direction of the subsatellite track. In general the azimuth is the angle of horizontal deviation, measured clockwise, of a bearing from a standard direction.

Backscatter. Scattering of radiation (or particles) through angles greater than 90° with respect to the original direction of motion.

Band. A specification of a spectral range (say, from 0.4-0.5 f!ID) that is used for radiative measurements. The term 'channel' is also in common use with the same meaning as 'band'. In the ITU convention (see Table 558) for the electromagnetic spectrum, the term 'band' refers to a specific frequency range, designated as L-band, S-band, X-band, etc.

Band-to-band registration (also referred to as co-registration). Refers to multispectral image resolution, i.e. how well the same scene is recorded in different spectral bands. Coregistration of spectral bands is measured by the displacement of corresponding pixels in two different bands from their ideal relative location. Two pixels are "corresponding" if their footprints should ideally coincide or if the footprint of one should ideally lie within a specific region of the footprint of the other.

Bandpass. Defined as the frequency band(s) over which a microwave radiometer detects radiation. The equivalent for IR radiometers is the filter response.

Bandpass filter. A filtering device that allows transmission of only a narrow band of frequencies (the other frequencies are blocked out). The spectral width of this filter is characterized by its bandwidth.

Bandwidth. Range of frequencies over which an instrument (or communication link) can be used. It is usually specified in terms of 3 dB points that is, frequencies at which the response has fallen by 3 dB or 30% from the mid-frequency response. Bandwidth may also refer to the width of a spectral feature as measured by a spectroscopic instrument.

Baroclinic waves (disturbances). Any migratory cyclone more or less associated with strong baroclinity of the atmosphere, as evidenced on synoptic charts by temperature gradients in the constant-pressure surfaces, vertical wind shear, and concentration of solenoids in the frontal surface near the ground.

Baseband. Band of frequencies, usually the lowest frequencies in a microwave communications system, where basic information is assembled. This spectrum is generally that provided to the microwave system to be delivered to a distant point in the same format and information content.

Bathymetry. Measurement of water body depths, in particular ocean floor surveys. Generally, bathymetry surveys cannot be directly performed from a satellite. However, there are some areas of satellite applications: - bathymetry surveys in coastal regions (with a SAR instrument) or of shallow bodies of water; the other method is the interpretation and correlation of radar altimeter data (the technique relies on the assumption that the relationship between the gravity field and bathymetry is uniform over relatively small areas ( = 200 x 200 km).


Beamsplitter. A mirror, sometimes built into a prism, with the ability of reflecting part of a beam of radiation and transmitting the other part. The 'splitting' or diverting is performed on the energy level (frequency-selective surfaces), not on the spectral level (no spectral separation by dispersion). Such a partially diverted beam may be used in color separation cameras, or for the superposition of images in special cameras or in Fourier Transform Spectrometers (FTS), generating an interferogram in combination with an interferometer.

Bias. In electronics the term refers to the application of a voltage between two terminals (electrodes) resulting in current flow (also referred to as 'forward bias'). The term 'reverse bias' refers to the application of a voltage in such a way that no current can flow. The term 'unbiased' designates that no voltage is applied.

Beat wave. A composite wave formed by the superposition of two waves having different frequencies (f1, fz) and wavenumbers (k1, kz). Beat waves form at the sum and difference frequencies (f1 ±fz) and wavenumbers (k1 ±kz). See also heterodyne detection.

Biological productivity. The amount of organic matter, carbon, or energy that is accumulated during a given time period.

Bioluminescence. Refers to the production of light from chemiluminescent reaction in living organisms. Although bioluminescence is very dim, it features prominently in the ecology of the seas, occurring in all oceans; it is produced by a wide variety of marine plankton and nekton.

Biomass. The total dry organic matter or stored energy content of living organisms that is present at a specific time in a defined unit (community, ecosystem, crop, etc.) of the Earth's surface.

Biomass burning. A recognized major source oftrace gases, including COz, NOz, CO, CH4, and of aerosol particles. It takes on many forms: burning of forested areas for land clearing, extensive burning of grasslands and savannas to sustain grazing lands, burning of harvest debris, use of biomass fuel for heating, forest fires induced by lightning or other hazards. The emissions of biomass burning represent a large perturbation to global atmospheric chemistry, especially in the tropics.

Biosphere. The portion of the Earth and its atmosphere that can support life. The part (reservoir) of the global carbon cycle that includes living organisms (plants, animals,) and lifederived organic matter (litter, detritus). The terrestrial biosphere includes the living biota (plants and animals), litter and soil organic matter on land; the marine biosphere includes the biota and detrius in the oceans.

Bistatic system. The bistatic remote-sensing concept refers to a measurement arrangement in which the transmitter and receiver locations are separated by a distance comparable to that of the target distance. In contrast, monostatic radars employ a transmitter and receiver at the same location (often using the same antenna) and measure the backscattered radiation. The great majority of all radars (SAR instruments, Doppler radars, etc.) in use today are monostatic.

Blackbody (BB). An idealized body that absorbs all the radiation incident upon it and reradiates it according the Planck's law.

Blaze wavelength. The wavelength of the highest efficiency for a ruled diffraction grating, the "blaze" being the controlled shape of the rulings on the grating.

Blooming. Refers to the saturation effect in image detection devices, like CCDs.

Body-pointing. Refers to the pointing technique of an instrument within the field of regard. The instrument is pointed along with its platform (satellite) into the desired direction.

Bolometer. A detector type making use of the change in electrical resistance of certain materials (with small thermal capacity) when their temperature is changed. The resistance of


most conductors varies with temperature, this change in resistance is measured by the bolometer. Bolometers are suitable detectors for the infrared and microwave regions.

Boresight. A technique for aligning sensors or detectors on a target.

Bragg scattering theory. According to this theory the normalized radar cross-section (NRCS) is proportional to the spectral energy density of the Bragg waves, i.e. of those surface waves with wave numbers ks that satisfy the Bragg resonance condition:

kB __ 4.n sin (} , where "-o denotes the radar wavelength and 8 the incidence angle.

Ao BRDF (Bidirectional Reflectance Distribution Function). Specifies the behavior of surface scattering as a function of illumination and view angles at a particular wavelength. BRDF is defined as being the ratio of the reflected radiance to the incident flux per unit area.2044l

Brightness temperature. A concept referring to the equivalent blackbody temperature for a given frequency (range) according to Planck's law. The term brightness temperature is often employed for data of radio/microwave observations where the radiation is in the Rayleigh-Jeans tail of the thermal distribution. It means that the source emits (at the frequency of interest) the same amount of radiation as a blackbody at the brightness temperature. Intensities are measured in terms of brightness temperature (that is, the temperature a blackbodywould have if it emitted an equal intensity of radiation at the same frequency). Examples of brightness temperature applications:

Measurement and/or computation of the 'top of the atmosphere brightness temperature' or 'troposphere moisture content' from data of particular channels of such sensors as: AVHRR, TOYS, etc.

• The measurement of ocean surface roughness at microwave frequencies (with a radiometer) permits estimates of ocean-surface wind speeds. The method employs the concept of brightness temperature anisotropy which increases with ocean-surface roughness. The SSM/I sensor of the DMSP series uses this principle to map ocean surface wind speeds.

• The Earth's surface brightness temperature can be measured by channel6 (TIR) of the Landsat TM sensor, or by the MWR instrument of ERS missions.

Cadastre. An official (governmental) land registry defining the ownership of a parcel along with ancillary information (description of parcel location, boundaries, shape and size, inventory of actual features and structures, value for taxation, etc.). Positional accuracies are an important issue of such registries. - Cadastral mapping takes many forms around the world, based on current and historic land registry, land reform policies, and available funding levels. In Europe the cadastre is linked to the legal land registration system within the context of a national geodetic reference system. In the US and Canada there is no central land registry (land registry information is maintained at multiple levels). In all parts of the world, however, land ownership information plays a key role in defining local and national economies and in managing natural resources and handling environmental issues.

Calibration. Characterization of a sensor (radiometer, spectrometer, etc., see also chapter 0.2) in the spatial, spectral, temporal and polarization responsive domains. The term 'calibration' is being used so often by different people that it has several additional meanings, such as: 1. The activities involved in adjusting an instrument to be intrinsically accurate, either before or after launch (i.e. 'instrument calibration'). 2. The process of collecting instrument characterization information (scale, offset, nonlinearity, operational and environmental effects), using either laboratory standards, field standards, or modeling, which is used to interpret instrument measurements (i.e. 'data calibration').

2044)See ERIM BRDF tutorial at URL: http://www.erim.org/on-line-docs/GUIDE/guide.frm.html


Candela ( cd). A unit of luminous intensity equal to one sixtieth of the luminous intensity of one square centimeter (1 cm2) of a blackbody surface at the solidification point of platinum.

Carbon cycle. A sequence of conversion processes from matter into energy. All reservoirs and fluxes of carbon; usually thought of as a series of the four main reservoirs of carbon interconnected by pathways of exchange. The four reservoirs - regions of the Earth in which carbon behaves in a systematic manner- are the atmosphere, terrestrial biosphere (usually includes freshwater systems), oceans, and sediments (includes fossil fuels). Each of these global reservoirs may be subdivided into smaller pools ranging in size from individual communities or ecosystems to the total of all living organisms (biota). Carbon is exchanged from reservoir to reservoir by various chemical, physical, geological, and biological processes.

Carrier. An electromagnetic wave in a communication path (basic center frequency of a signal) which does not carry information but is generally modulated by another wave (subcarrier) which contains the information.

Carrier phase. Refers to the fraction of a cycle, often expressed in degrees (360° to a cycle). Carrier phase can also mean 'the number of complete cycles plus a fractional cycle.' In GPS terminology, carrier phase refers to a receiver capable of locking onto a GPS signal and keeping track of the whole number of cycles of the carrier; this method creates a cumulative phase of the signal which is also known as 'integrated Doppler.' Much higher ranging accuracies can be obtained with carrier phase than without carrier phase tracking.

Catadioptric telescope (see also Schmidt telescope under Telescopes). Refers to a telescope design with a large FOV to eliminate image distortions (a catadioptric telescope design incorporates the best features of both the refractor and reflector, i.e., it has both reflective and refractive optics. The Schmidt telescope has a spherically shaped primary mirror. Since parallel light rays, that are reflected by the centre of a spherical mirror, are focused farther away than those reflected from the outer regions, Schmidt introduced a thin lens (called the correcting plate) at the radius of curvature of the primary mirror. Since this correcting plate is very thin, it introduces little chromatic aberration. The resulting focal plane has a field of view several degrees in diameter.

Charge-Coupled Device (CCD). A CCD is a photosensitive solid-state imaging sensor (detector) implemented with large-scale integration technology (normally based on MOS technology). A MOS:.:;apacitor is a three-layer sandwich formed by positioning a metal electrode, insulated by a layer of silicon dioxide, onto a silicon substrate. Incident radiation into the system is sampled by photodetectors, converted into an electronic charge and trapped in the depletion region of the substrate. The isolated charge packets are transported by manipulating potential wells (place of minimum potential) within the substrate. The ability to store a charge is fundamental to the operation of CCDs.lt corresponds to a memory device storing analog quantities. - CCD readout techniques employ clock-controlled circuits which transfer these: charges to a matching grid of elements and shift all charges by one row at a time. -The CCD technology was first demonstrated in 1969 at the Bell Laboratories. See also chapter 0.4.2.1.

Charge Injection Device (CID). A photo-sensitive image sensor (detector) implemented in large-scale integration technology. Charge packets are typically measured by injecting them into a substrate,or by shifting charge packets under an electrode to induce a voltage on the capacitance formed'by the electrode and the substrate. ACID can be randomly addressed. The pixel structure is contiguous with maximum surface to capture incident light which is useful for sub~pixel measurement (0.4.2.2).

Chemiluminescence: Emission of light as a consequence of a chemical reaction, the result of thermal generation of electronic excited states. Chemiluminescence can be seen when occurring in the dark.·~ A number of chemical reactions generate products not in their lowest energy states, but rather in upper levels. That is, some of the exothermicity of the reac-


tion is channeled internally into electronic, vibrational, or rotational energy of one or more of the products, rather than being released as heat. The excited product molecules may emit this energy as light, known as chemiluminescence because of the chemical source of energy. -The term of surface chemiluminescence belongs also into this context. In this scheme air is passed over a chemiluminescent plate causing the gas ( eg., ozone) molecules to diffuse into the coating of the plate and in turn generating a chemiluminescent reaction. The reaction sequence causes the emittance of light (radiation) whose intensity is proportional to the ozone concentration.

Chirp principle. A microwave modulation technique in which the frequency of the transmitted microwave pulse is not constant but linearly changed in a positive sense (up-chirp) or in a negative sense (down-chirp). A frequency-modulated chirp is a signal with a (linear) increase in frequency or pitch.

Chlorofluorocarbons (CFCs). A family of inert, nontoxic, and easily liquefied chemicals used in refrigeration, air conditioning, packaging, and insulation, or as solvents or aerosol propellants. Because they are not destroyed in the lower atmosphere, they drift into the upper atmosphere, where - given suitable conditions - their chlorine components destroy ozone.

Chlorophyll. A green pigment essential for photosynthesis found in plants. It usually occurs in discrete bodies (chloroplasts) in plant cells, and is what makes green plants green. In remote sensing of aquatic ecosystems, the reflected radiance is related to the concentration of chlorophyll and other associated pigments. Since chlorophyll is green, the color of reflected light changes from blue to green as the concentration of chlorophyll increases. The concentration of chlorophyll is used to estimate the abundance of phytoplankton in ocean waters, and hence the abundance of ocean biota.2045l

Climate. The statistical collection and representation of the weather conditions for a specified area during a specified time interval, usually decades, together with a description of the state of the external system or boundary conditions. The properties that characterize the climate are thermal (temperatures ofthe surface air, water, land, and ice), kinetic (wind and ocean currents, together with associated vertical motions and the motions of air masses, humidity, cloudiness and cloud water content, groundwater, lake winds, and water content of snow on land and sea ice), and static (pressure and density of the atmosphere and ocean, composition ofthe dry air, salinity ofthe oceans, and the geometric boundaries and physical constants ofthe system). These properties are interconnected by various physical processes such as precipitation, evaporation, infrared radiation, convection, advection, and turbulence.

Climate change. The long-term fluctuations in temperature, precipitation, wind, and all other aspects of the Earth's climate. External processes, such as solar-irradiance variations, variations of the Earth's orbital parameters (eccentricity, precession, and inclination), lithosphere motions, and volcanic activity, are factors in climatic variation. Internal variations of the climate, e.g., changes in the abundance of greenhouse gases, may also produce fluctuations of sufficient magnitude and variability to explain observed climate change through the feedback processes interrelating the components of the climate system.

Correction/Calibration methods for sensor data (see chapters 0.2 and 0.2.2)

Cloud. A visible mass of condensed water vapor particles or ice suspended above the Earth's surface. Clouds may be classified by their visual appearance, height, or form.

Cloud albedo. Reflectivity that varies from less than 10 to more than 90 percent of the insolation and depends on drop sizes, liquid water content, water vapor content, thickness of the cloud, and the sun's zenith angle. The smaller the drops and the greater the liquid water content, the greater the cloud albedo, if all other factors are the same.

2045) Courtesy of W. Esaias of NASNGSFC


Cloud feedback. The coupling between cloudiness and surface air temperature in which a change in surface temperature could lead to a change in clouds, which could then amplify or diminish the initial temperature perturbation. For example, an increase in surface temperature could increase evaporation; this in turn might increase the extent of cloud cover. Increased cloud cover would reduce the solar radiation reaching the Earth's surface, thereby lowering the surface temperature. This is an example of negative feedback and does not include the effects of longwave radiation or advection in the oceans and the atmosphere, which must also be considered in the overall relationships within the climate system.

Cloud microphysics. Study of cloud and precipitation particles (individual or populations) and their interactions with the environment. Of key importance are mass exchange processes such as nucleation, growth, and fallout leading to the broad characteristics of clouds and precipitation.

Code Division Multiple Access (CDMA). Refers to an access scheme which employs spread-spectrum modulations and orthogonal codes to share a communication link among its users. In the CDMA scheme, all users transmit simultaneously and at the same frequency, with each being assigned a unique pseudorandom noise code. Usually, the data is first phase-modulated by a carrier and then the carrier is hi-phase-modulated with a pseudorandom noise (PNR) code. This concept generates a wide bandwidth, low-energy spread spectrum signal.

Coherence. A fixed relationship between the phases of waves in a beam of radiation of a single frequency. Two beams of light are coherent when the phase difference between their waves is constant; they are noncoherent if there is a random phase relationship. In active measurement systems like radars, coherence refers to the availability of phase and amplitude measurements of the radar cross section of the recovered signals. Coherence provides the ability to maximize SNR and to measure other features like target radial velocity.

Coma. An off-axis aberration whereby the outer periphery of a lens system has a higher (or lower) magnification then the central portion of the lens. The image typically is comet shaped.

Contrast. The ratio of a certain quantity of radiation between the brightest and darkest part of an image or between two arbitrary places of an image, where the contrast is to be determined.

Convection (meteorology). Vertical wind motions and associated horizontal circulations associated with buoyancy.

Convolution. Mathematical process, appearing in linear or circular form, that models the input-output filtering process.

Convolution filter. A linear filter type as used in digital image processing of which the window operation has a mathematically linear character (weighted summation). Examples are low-pass filter, high-pass filter, gradient filters, Laplacian filters, etc.

Corona. Refers to the outer atmosphere of the sun whose structure is controlled by solar magnetic fields. The corona has temperatures between one and three million degrees. It merges into the solar wind at its upper boundary about 1-2 solar radii above the visible surface of the photosphere.

Crossover (difference). A crossover is defined as the intersection points of the satellite ground track with itself (due to Earth rotation). At this location, the two crossing passes (one ascending and one descending) provide independent subsatellite ground track measurements at the same location but at different times. In altimetry crossover differences contain information about uncertainties in the satellite ephemeris and therefore enable correction of radial orbit error.


Crossover point. Refers to radar measurements concerning the curves showing the dependency of the radar backscatter behavior on the incidence angle of the radar transmission signals onto surfaces of differing roughness. The crossover point is the incidence angle where the diffuse region changes into a specular region on the curves (or: the incidence angle where the effect of soil roughness vanishes and the radar backscatter value is determined by the presence of soil moisture).

Cryosphere (from the Greek word 'Kryos', icy cold). The Earth's cryosphere consists off our main elements: sea ice, seasonal snow on land, land ice (including glaciers, ice sheets, and ice shelves), and permafrost. The time scales on which these elements impact human activity range from daily to seasonal for sea ice and snow, while ice shelves respond in the range of 10-100 years, ice sheets (Antarctic and Greenland) have periods in the order of 1000-10,000 years. Land ice occupies about 11% of the continental surfaces. Sea ice and ice shelves spread around 7% of the total oceanic area.

Decibel (dB) - named in honor of Alexander Graham Bell. A measurement of signal strength, properly applied to a ratio of powers. For the signal power P compared by a ratio to a reference power Pref, the definition is: Pctb = 10logw (PIP ref). As an example, the power ratio of 1/2 corresponds to "3 dB", derived from: logw (0.5) =0.3010.

Deforestation. The removal of forest stands by cutting and burning to provide land for agricultural purposes, residential or industrial building sites, roads, etc., or by harvesting the trees for building materials or fuel. Oxidation of organic matter releases C02 to the atmosphere, with possible regional and global impacts.

Densiometer. A photometer designed for measuring the optical density of a material, generally a photographic image by visual or photoelectric effects.

Depolarization ratio. The ratio of intensities oflight scattered perpendicular and parallel to the E-vector of the incident radiation.

Detector. A device that detects and linearly transduces radiative power into an electrical signal. Direct detectors may be categorized as photon detectors (an electrical signal is produced by free charges on the detector surface from the incident photons) or thermal detectors (an electrical signal is produced due to the temperature change). Detectors may also be classified according to their arrangement: single line detectors, array detectors. Thermal detectors usually require cooling (active or passive). Infrared radiation is 'thermal' by nature, hence the detector is affected by the medium that is measured. As a rule of thumb, the longer the IR wavelength that is to be measured, the colder the detector must be. In the VNIR region the detector element temperatures rarely need to be below 200 K. From 1-17 ~m, temperatures are typically in the range 50-80 K. The longer wavelengths of the microwave region usually demand temperatures below 20 K. The detectivity of a cooled detector is much higher than one operating at room temperature The noise contribution from background radiation at 300 K is several orders of magnitude higher than that of the 4 K surroundings of the detector (see 0.4).

Detector types for spectral ranges.2046) From the UV to VNIR (0.3-1 ~m), silicon photodiodes and photoemissive devices such as photomultiplier tube (PMT) are normally used. 2047) Between 1-12 ~m, two technologies dominate: InSb (indium antimonide) from 1-5.5 ~m, and HgCdTe (mercury cadmium telluride, also referred to as MCT). Both, lnSb and MCT operate in a photovoltaic mode. For the spectral range of 12-35 ~m, photoconductors or MCT are being used. Beyond 30 ~m, the only available technology in use is the semiconductor bolometer.

Dewar [after Sir James Dewar (1854-1928) a Scottish chemist and physicist]. The term denotes a vessel to store hot or cold substances over long periods of time. It is a container with

2046) R. Beer, "Remote Sensing by Fourier Transform Spectrometry," John Wiley & Sons, Inc., New York, 1992, Chapter 4.1.2

2047)Note: Silicon is transparent in the spectral ranges of 1.4-7 ~m and from 25 ~m to well beyond 100 ~m


at least two walls and a space between the walls evacuated so as to prevent the transfer of heat. There are various techniques in use for minimizing the heat transfer in spaceflight for liquid helium, like: multilayer insulation, multiple reflective surfaces in vacuum, vaporcooled shields, passive orbital disconnect struts, etc.

Dielectric. An insulating material or a very poor conductor of electric current. When dielectrics are placed into an electric field, practically no current flows in them because, unlike metals, they have no loosely bound, or free, electrons that may drift through the material. Instead, electric polarization occurs, reducing the electric field within the dielectric. A vacuum is the only perfect dielectric. - A dielectric gas is a nonconductor of electricity to high applied electrical stress; a gas with a high breakdown voltage.

Dielectric constant. A property of an insulating material (a dielectric) equal to the ratio of the capacitance of the capacitor filled with the given material to the capacitance of an identical capacitor in a vacuum without the dielectric material (x=C/C0 ).

Diffraction. A process by which the direction of radiation is changed so that it spreads into the geometric shadow region of an opaque or refractive object that lies in a radiation field. Diffraction is an optical "edge effect," (differing only in degree from scattering) caused by particles with diameters of the same order of magnitude as, or larger than, the wavelength of radiation; scattering is caused by smaller objects. Diffraction causes a modification which light undergoes in passing by the edges of opaque bodies or through narrow slits or in being reflected from ruled surfaces, and in which the rays appear to be deflected producing fringes of parallel light and dark or colored bands.

Diffraction grating. A system of close equidistant and parallel lines or bars (also grooves) on a polished surface used for producing spectra by diffraction.

Diffraction-limited system. An optical system in which aberrations are negligible with respect to diffraction effects.

Diffuse radiation. Radiation propagating in many different directions through a given small volume of space (converse is 'specular radiation'). The ideal form of diffuse radiation is isotropic radiation (uniform radiation in all directions).

Digital count. Refers to the total number of pixels occurring in an image for each possible data value.

Digital Earth. A vision/initiative of Vice President AI Gore, ~resented in a speech at the California Science Center in Los Angeles, on Jan. 31, 1998. 048) The proposed concept model of "Digital Earth"refers to a multi-resolution, 3-D representation of Earth, into which geo-referenced data can be embedded. A "Digital Earth" could, for instance, provide a mechanism for users to navigate and search for geospatial information, etc. - Obviously, such an objective is so vast, that no one organization in government, industry or academia could undertake such a project. A vast standards infrastructure is needed to make it happen! The benefits of such a seamless system are apparent to the entire Earth Observation community.

Digital filter. A digital device (or a mathematical procedure) capable of altering the magnitude, frequency or phase response of a digitally encoded input signal (it may also selectively transmit digital signals).

Digital Terrain Model (DTM). Refers to a land surface represented in digital form by an elevation grid or tables of three-dimensional coordinates to form surface contours. The DTM definition is identical to that of aDEM (Digital Elevation Model). A DTM or DEM forms the basic building block for combining other data for analysis. For instance, digitized

2048)G. W. Fuller, ''A Vision for a Global Geospatial Information Network (GGIN) Creating, Maintaining and Using Globally Distributed Geographic Data, Information, Knowledge and Services," ASPRS, May 1999, pp. 524-538


spatial data (images) can be draped onto aDEM and analyzed using a GIS. The quality of such aDEM depends on the spatial resolution (in particular the topographic accuracy) of image data available. Interferometric SAR data and/or altimeter data are currently the best sources for DEM generation.

Diode. A semiconductor diode consists of a crystal (two terminals), part of which is n-type (negative charge) and part p-type (positive charge). The boundary between the two parts is called a p-n junction. There is a population of holes on the p-type side of the junction and a population of electrons on then-type side. 2049) The p-n junction of the diode conducts current with one polarity of applied voltage but not with the other polarity. Rectification (current flow only in one direction) is a very important characteristic of the p-n junction. Another characteristic of the p-n junction is its direct conversion capability of radiant energy into electrical energy (optoelectronic effect). An incident photon, striking a p-n junction, has the same effect as a hole (positive charge); it is absorbed thereby creating electron-hole pairs. The resulting current can be detected (see photodiode).

Dipole. An electric system composed of two equal charges of opposite sign, separated by a finite distance; e.g. the nucleus and orbital electron of a hydrogen atom. An ordinary bar magnet is a magnetic dipole.

Dipole antenna. A type of array consisting of a system of dipoles. A dipole antenna differs from a dish antenna in that it consists of many separate antennas that collect energy by feeding all their weak individual signals into one common receiving set.

Discrete Fourier Transform. A mathematical method of transforming a time series into a set of harmonics in the frequency domain and vice versa.

Dispersion of spectra. The following methods are used to separate radiation (light) into its component spectra (colors):

Refraction. Historically, prisms were first used to break up or disperse light into its component colors. The path of a light ray bends (refracts) when it passes through the prism, i.e. from one transparent medium to another (from air to glass).

• Diffraction. Diffraction gratings are composed of closely spaced transmitting slits on a flat surface or alternate reflecting and non-reflecting grooves. - In any grating spectrometer, if a slit aperture is moved along the surface where the spectral lines are focussed, the lines are transmitted successively through the aperture. Interference. An interferometer divides a wave front by semitransparent surfaces. This allows the beams to travel different paths. The beams are then recombined generating interference patterns. AOTF (Acousto-Optic Tunable Filter). The AOTF principle is based on acoustic diffractions of light in an anisotropic medium. An AOTF device consists of a piezoelectric transducer bonded to a birefringent crystal. When the transducer is excited by an applied RF signal, acoustic waves are generated in the medium. The propagating acoustic wave produces a periodic modulation of the index of refraction. This provides a moving phase grating that, under proper conditions, will diffract portions of an incident beam. -In operation, acousto-optic tunable filters resemble interference filters and can replace a filter wheel, grating, or prism in many applications (see 0.4.5).

Diurnal cycle (Lat. diurnalis). A 24-hour (daily) cycle associated with solar heating during the day and radiative cooling during the night. A periodic cycle affecting nearly all meteorological variables.

Doppler effect (after Christian J. Doppler, Austrian physicist, 1803-1853). The alteration in frequency of a wave of radiation caused by relative motion between the observer and the

2049) Note: The term "hole" refers to a fictitious particle which carries a positive charge and moves, under the influence of an applied electric field (bias), in a direction opposite to that of an electron. The motion of electrons and holes in semiconductors is governed by the theory of quantum mechanics.


source of radiation.- The acoustic Doppler effect applies to the propagation of source waves; the optical Doppler effect depends on the relative velocity of the light source and the observer; the thermal Doppler effect causes a widening of the spectral lines.

Doppler radar. A radar system which differentiates between fixed and moving targets by detecting the change in frequency of the reflected wave caused by the Doppler effect. The system can also measure target velocity with high accuracy.

Doppler shift. Displacement of spectral lines (or difference in frequency) in the radiation received from a source due to its relative motion in the line of sight. Sources approaching (-) the observer are shifted toward the blue; those receding (+),toward the red. Used to determine radial distance.

Delay Doppler radar altimeter. An evolving technique which exploits signal processing algorithms borrowed from SAR processing schemes. When applied to an ocean-observing altimeter, real-time on-board processing achieves an integration level of the received signal that is about a magnitude higher (tenfold) than that achieved in conventional radar altimeters. This in turn translates into a tenfold reduction in required radiative power of the transmitter (or into a smaller radar antenna or a combination of both effects), improving instrument performance considerably. 2050)

Downlink. Refers to the communication direction from a satellite (or aircraft) to a ground station. The prime information in this link is usually referred to as 'telemetry.' There may be different logical links in a downlink for instrument data and for the return (verification) of the telecommand data. In very elaborate communication systems with intermediate geostationary transmission satellites, the term 'downlink' is usually replaced by 'return link' to avoid confusion.

Dryline. A meteorological term referring to a boundary which separates moist and dry air masses. The dryline is an important factor in the frequency of severe weather in the Great Plains of the continental USA. It typically lies north-south across the central and southern high Plains states during the spring and early summer, separating moist air from the Gulf of Mexico and dry desert air from the southwestern states.

Dual spin. Refers to a spacecraft design whereby the main body of the satellite is spun to provide attitude stabilization. In this concept the antenna assembly is despun by means of a motor and bearing system in order to continually direct the antenna earthward. The dualspin configuration thus serves to create a spin-stabilized satellite.

Duty cycle. Fraction of orbital period in which a sensor (or a sensor mode) is actually operational, determined by the overall power limitations of the payload. The concept of a duty cycle applies in particular to sensors with large power requirements such as active sensors, in particular SAR instruments.

Dwell time. The short period of time during which a detector collects radiation from a target area or volume. -A very short dwell time usually results in a low (i.e. poor) signal-to-noise (SNR) ratio with all its problems of proper signal recognition and discrimination. A small dwell time also implies 'fast' detectors and electronics.

Dynamic range. The dynamic range of a sensor system is determined by the ratio of the maximum observable energy (Omax) and the minimum still-useful energy (noise level Omin); it is defined in decibels (dB) as 10 log (OmaxiOmin)· All radiant energy < Omin vanishes into noise, while the energy above Omax disappears into the saturation of the detector (see also Signal-to-Noise-Ratio).

Electromagnetic spectrum (EMS). The total range of wavelengths or frequencies of electromagnetic radiation, extending from the longest radio waves to the shortest known gam-

2050) G. H. Fountain, Robert E. Gold, eta!., "A Technology Path to Distributed Remote Sensing," Small Satellites for Earth Observation, 2nd International Symposium of IAA, Berlin, April 12-16, 1999, pp.189-193


rna rays. - EMS energy for passive remote sensing, as derived from the sun, is either reflected sunlight or re-emitted thermal radiation. The transfer mode of reflected radiation is dominant in the window associated with VNIR and SWIR, while the preferred mode of long-wave transfer (thermal radiation) is in the TIR window (see also Figure 422 on page 1365).

In the VNIR and SWIR (0.4- 3 !till) wavelength regions, the predominant mode of energy detection is that of reflected sunlight

• In the MWIR region (3-6 !till) the detected energy is a mixture of solar reflected and thermally emitted radiation In the TIR window ( 6-13 !till), practically all energy received (detected) is attributed to thermal emission.

Note: Although the sun, with a brightness temperature of about 6000 K, is much hotter than the Earth's surface at about 290 K, the dominance of the Earth's thermal energy at longer wavelengths is a result of geometry (the sun subtends only about 0.5° at the Earth- the sun's disk angle is actually about 32'), and that the solar energy is subsequently scattered by the Earth's surface into 2:rc space.

Electron tube. The term is the generic name for a class of devices that includes: vacuum tubes, phototubes, gas-filled tubes, cathode-ray tubes, and photoelectric tubes. An electron tube typically consists of two or more electrodes enclosed in a glass or metal-ceramic envelope, which is wholly or partially evacuated. Its operation depends on the generation and transfer of electrons through the vacuum from one electrode to the other. Electron tubes have properties that cannot be surpassed by solid-state devices for particular applications. Their thermal ruggedness, operating efficiency, and high-power capabilities are features well beyond those of solid-state devices. As components of electronic systems, electron tubes are used as amplifiers, rectifiers, signal generators, and switches (in particular in the microwave region).

Electron volt (eV). A unit of energy used in atomic and nuclear physics; the kinetic energy acquired by one electron in passing through a ~otential difference of 1 volt in vacuum. 1 e V = 1.602x 10·12 erg (or= 1.602x I0-19 Joule)2 51l. An electron with an energy of 1 eV has a velocity of about 580 km/s. The wavelength associated with 1 eV is 12,398 A. The eV is a convenient energy unit when dealing with the motions of electrons and ions in electric fields; the unit is also the one used to describe the energyofX-rays and gamma-rays. Nuclei in cosmic rays typically have energies ranging from a about 1 MeV (or less) to many Ge V per nucleon.

Electrooptics. An imaging technique which uses optics, such as the collimation of light beams and the magnification of images by lenses and mirrors, rectification by prisms, and diffraction by gratings (usage: generally in the VNIR spectrum). - The newer devices of electrooptics make use of more electronic components such as the generation of light by lasers and solid state devices, featuring electronic scanning of the images and data presentation on electrically activated displays. To an increasing extent, computers are employing electrooptical techniques for their own operation and display. See also chapter 0.10.2.

Emissivity (E). The ratio of radiative energy (power) emitted by a body to that emitted by a blackbody at the same temperature. For all cases: E(A.) :s; 1.

Energetic particles. These are electrons, ions, or atoms that have much higher energies than expected for the temperature oft he gas in which they are transported (the solar wind is such a transport medium).

Energetic Neutral Atom (ENA). ENAs are created in the inner magnetosphere when charge exchange collisions occur between energetic ions and the cold neutral population of

2051) The energy unit Joule is named in honor of James Prescott Joule (1818-1889), a British physicist who established that the various forms of energy- mechanical, electrical, and heat- are basically the same and can be changed into one another. Thus he formed the basis of the taw of conservation of energy, the first law of thermodynamics.


the Earth's extended atmosphere. ENAs travel in approximately straight-line trajectories away from the charge-exchange sites (because gravitational forces are negligible for typical energies of interest and they are unaffected by the Earth's electric and magneticfields) and carry with them valuable information about the pitch angle and energy distributions of the ion population from which they were emitted. As of the 1990s the ENA emissions can actually be sensed remotely by appropriate imagers. Several NASA missions have such instrumentation: POLAR, IMAGE, and TWINS.

ENSO (El Nino Southern Oscillation). ENSO is regarded as a large-scale interannual climate variability (anomaly) especially with regard to precipitation regimes and sea surface temperature (SST) changes in the tropical Pacific Ocean. The warming effect of ENSO can dramatically alter precipitation patterns over much of the Pacific basin.lts recurrence every three to seven years provides a clear signal of climate variability on a global scale. Its land surface manifestations are illustrated by heavy torrential rains on the west coast of South America and droughts in Sahelian Africa, southern Africa, Australia, and eastern Brazil. The forecasting of ENSO events can greatly benefit the peoples and economies of the impacted areas. Scientists believe El Nino conditions between Australia and South America are sparked when the steady westward trade winds weaken and even reverse direction. This wind shift moves a large mass of warm water, normally situated near Australia, eastward along the equator, pushing it toward the coast of South America. The transportation of such a large body of warm water affects evaporation, causing rain clouds to form that, in turn, alter typical atmospheric jet stream patterns around the world.

Background: In the 16 century, the El Nino climatic phenomenon was first observed by Peruvian fisherman as a warm current running along the coast of Peru. Since this recurrent event happened around the Christmas season, they christened the warm current as El Nino (meaning Christmas in Spanish). This virtually periodic phenomenon appears at two- to seven-year intervals, it has economic and environmental consequences that are sometimes catastrophic. The entire climate is thoroughly disturbed. Due to the warming of the Peruvian waters, normally the most productive in the world, the ocean is depleted of nutrients, causing rarefaction of the phytoplankton. A consequence of the disappearance of the aquatic life is a massive destruction of oceanic bird life.

Eotvos experiment. An experiment performed in 1909 by the Hungarian physicist Roland Ei:itvi:is (1848-1919) to establish that the gravitational acceleration of a body does not depend on its composition- i.e. that inertial mass and gravitational mass are exactly equal (!atera major principle of Albert Einstein's general theory of relativity). In Einstein's version, the principle asserts that in free-fall the effect of gravity is totally abolished in all possible experiments and general relativity reduces to special relativity, as in the inertial state. Today, the linear gradient of gravity is defined in units of Ei:itvi:is, where 1 Ei:itvi:is = w-9 s-2 ; i.e. difference of w-9 ms-2 acceleration per meter. The vertical gradient of gravity at the Earth's surface is about 3100 Ei:itvi:is.

Ephemeris. A tabular statement of the spatial coordinates of a celestial body or a spacecraft as a function of time.

Equatorial electrojet current. Current created around the Earth's equator by counter-rotating electrons and protons. This electrojet current causes ionization, and subsequently UV radiation, similar to auroral phenomenon usually associated with the Earth's F-Layer.

Equinox. Either of two points on the celestial sphere where the celestial equator intersects the ecliptic. At these two instances the sun is exactly above the equator and day and night are of equal length (see also vernal equinox).

Equivalence Principle (EP). A fundamental law of physics that states that gravitational and inertial forces are of a similar nature and often indistinguishable. EP in fact states that two


fundamentally different quantities, inertia and passive gravitational mass, always be exactly proportional to one another. This is usually interpreted as implying that the two quantities are equivalent measures for a single physical property, the quantity of mass of an object; hence, the term Equivalence Principle. A direct consequence of this Equivalence Principle is the 'universality of free fall' such that all objects fall with exactly the same acceleration in the same gravity field. EP turned out to be a major principle of Albert Einstein's general theory of relativity. The Strong or Einstein Equivalence Principle states that all of the laws of physics (not just the laws of gravity) are the same in all small regions of space, regardless of their relative motion or acceleration. In the Newtonian form, EP implies that, within a windowless laboratory freely falling in a uniform gravitational field, experimenters would be unaware that the laboratory is in a state of nonuniform motion. All dynamical experiments yield the same results as obtained in an inertial state of uniform motion unaffected by gravity. Experiments with ordinary pendulums test the principle of equivalence to no better than about one part in 105. The Hungarian physicist Roland Ei:itvi:is suggested (1909) that the attraction ofthe sun upon test masses could be compared with the inertial forces of the Earth's orbital motion about the sun. In the 1960s a series of careful observations (employing up-to-date methods of servo control and observation) were conducted by the American physicist Robert H. Dicke and his colleagues. They found that the weak equivalence principle held to about one part in 1011 for the attraction of the sun on gold and aluminum. A later experiment, with very different experimental arrangements, by the Russian researcher Vladimir Braginski, gave a limit of about one part in 1012 for platinum and aluminum. -A future NASNESA mission, called STEP (Satellite Test of the Equivalence Principle) or MiniSTEP, with a probable launch in 2005, has the objective to test EP to a precision of 1 part in 1018.

Equivalent (or effective) Isotropic Radiated Power (EIRP). A measure of power radiated by an antenna in the direction of a receiver, expressed as the equivalent power that would have to be radiated uniformly in all directions.

Erlang. A measure of communication (telephone) traffic load expressed in units of hundred call seconds per hour (CCS). One Erlang is defined as the traffic load sufficient to keep one trunk busy on the average and is equivalent to 36 CCS. The measure is also used for DCS (Data Collection Satellite) access capabilities.

Exit Aperture

Optimal System Etendue: A1 Ql = A2Q2

Entrance Aperture

Figure 421: Definition of etendue

Etendue. The term (French for 'extent') describes a very fundamental property of an optical system, namely A Q, the product of the area A of a light beam and the solid angle Q contained within a beam. The importance of etendue lies in the fact that it is one of the major factors in determining the SNR (Signal-to-Noise Ratio) of a system; it is in fact a design pa-


rameter which can be maximized by the proper choice of configuration. Etendue has the units: cm2 sr.lt is a property that is at best conseiVed through an optical train, i.e., the system etendue will be that of lowest value in any part of the system. Z05Z)

Excimer. In photochemistry a molecular aggregate formed by loose association of an excited state and a ground state of the same compound, where such association does not occur between two ground state molecules.

Extinction. The superimposed effect of two radiation effects that cancel each other, e.g. absorption and scattering.

F-Layer. One of the three regions (D, E, and F) of the Earth's ionosphere. The F-Layer constitutes the highest region, ranging from about 160-500 km. Within the F-Layer precipitating electrons from the magnetosphere cause ionization critical to long-wave radio communication. This ionization is typically caused by electrons with a kinetic electron energy < 1 keY. Ionization within the F-Layer may be characterized by sensors designed to measure UV radiation. F-Layer electron density is usually two to four orders of magnitude higher that that of the D- and E-Layers.

False color. A color imaging process which produces an image that does not correspond to the true color of the scene (as seen by the eye).

Fast Fourier Transform (FFT). An algorithm that is often used to implement Discrete Fourier Transforms.

Feedback mechanisms. A sequence of interactions in which the final interaction influences the original one. Negative feedback: An interaction that reduces or dampens the response of the system in which it is incorporated. Positive feedback: An interaction that increases or amplifies the response of the system in which it is incorporated.

Layer Altitude Major Components Production Cause D 70-90 km No+,oz+ Lyman Alpha, X-rays E 95 -160 km oz+,No+ Lyman Beta, Soft X-rays, UV continuum F 160-500 km o+,N+,No+ HE II, UV continuum

Table 560: Ionospheric layers and physical causes of ionization

Field of Regard (FOR). The pointing capability of a sensor with regard to the cross-track direction and/or along-track direction may provide additional coverage to the sensor in its orbit. This can be an advantage for monitoring (or imaging) events that are outside the swath width [or FOV(Field of View)] of a regularly nadir-pointing instrument.- An imaging sensor with a cross-track and an along-track pointing capability may have the potential of stereo imaging by taking the same image from different along-track positions in the same orbit.

Field of View (FOV). The total range of viewing of a sensor into the direction of the target. The cross-track component ofFOV is equivalent to the swath width (see also IFOV).

Filter (in optical sensors). A device that- by interference absorption or reflection- selectively modifies the radiation transmitted through an optical system (see also 'convolution filter').

Fluorescence. Refers to the absorption of a photon of one wavelength and re-emission of one or more photons at longer wavelengths (known as Stoke's shift), especially the transformation of ultraviolet radiation into visible light. Plants re-emit a portion of the absorbed radiant energy in the visible region into the red and near-infrared region (0.65-0.75 ~m). The distribution of wavelength-dependent emission intensity caused by a given wavelength

2052) R. Beer, "Remote Sensing by Fourier Transform Spectrometry," John Wiley & Sons, New York, 1992


excitation is known as the emission spectrum. The method of fluorescence has its advantages over other spectroscopic methods mainly due to its high sensitivity (applications in cell biology, photochemistry and the environmental sciences).- Note, since lasers are used as the excitation light source to induced fluorescence, this active remote-sensing method has become known as the laser-induced fluorescence (LIF) technique.

Focal length (f). Distance measured along the optical axis from the image to the plane, where the axial imaging cone of light intersects the input light bundle. The F-number or Fstop is defined as f/d (the focal length divided by the diameter ofthe lens opening). In antenna design the term focal length refers to the distance from the center feed to the center of the dish.

Footprint. Refers to the projection of the instantaneous area of coverage of a sensor (or antenna) onto the Earth's surface. A footprint may also be the instantaneous area of visibility of a data collection platform on a satellite.

Fonvard error correction (FEC). A transmission scheme which adds unique codes to the digital signal at the source so errors can be detected and corrected at the receiver.

Fourier Transform Spectrometer (FTS). An optoelectronic (or an optomechanical) instrument, usually for the infrared region of the spectrum, providing high spectroscopic resolution and sensitivity for remote-sensing applications (Earth surface imaging, atmospheric soundings, etc.). The technique employs the Fourier series concept as a means of converting a detector signal output - referred to as the interferogram - into a form useful for spectral analysis. There are several ways in which the detector signal can be created from the incident radiation. The approach taken by the majority of FTS instruments is to use an interferometer (Michelson, Sagnac, Fabry-Perot, etc.) and corresponding foreoptics (lenses) to create the interference pattern in such a way that each optical frequency is coded as a unique electrical signal output of the detector. The amplitude of each frequency is proportional to the incident radiation (see also chapter 0.9 on page 1258).

Frequency Division Multiple Access (FDMA). A process that shares a spectrum offrequencies among many users by assigning to each a subset of frequencies in which to transmit signals. Each user is assigned a unique center frequency within the operational bandwidth.

Full Width Half Maximum (FWHM). In the microwave region the resolution is often stated in terms of'half-power points' or 'half-power response width' ofthe measuring system. The half-power width of a response is easier to describe than true resolution because the concept does not involve the contrast of the target. -The true resolution for targets of any character can be derived from the actual response and estimated from the half-power width (resolution) of microwave instruments.

Gain. A measure of the amplification of the input signal in an amplifier. The gain of an amplifier is often measured in decibels (dB), which is ten times the common logarithm of the ratio of the output power of the amplifier to the input drive power [ = 10 log (QzfQI)].

Galilei (Gal or gal). A unit of acceleration, 1 gal= 1 cm/s2; 1 milligal = w-3 cm/s2. The term is commonly used in gradiometry.

Geocoding. Registration of images to the reference geometry of a map. In this process the imagery is corrected for all source-dependent errors and transformed to the desired map projection, and resampled to a standard pixel size. This is also called georeferencing.

Geodesy. The science of measuring the shape (and size) of the Earth, the geoid. A geodesic is the shortest line between two points on a mathematically derived surface (as a straight line on a plane or an arc of a great circle on a sphere). In general relativity the terms geodesic (noun) and geodetic (adjective) refer to paths followed by massive bodies ('geodesics') and light rays ('null geodesics') in curved four-dimensional space-time.


Geographical Information System (GIS). A combination of mutually referring data sets of various kinds of position-bound thematic data (database) and the necessary software to visualize this database, to manipulate it interactively and to analyze it in order to attain meaningful results.

Geoid. The Earth's conceptual gravitational equipotential surface (an ellipsoid) near the mean sea level, used as a datum for gravity surveys (a hypothetical ocean surface at rest). The geoid also serves as a reference surface for topographic heights, for example, as they are shown on maps. The geoid itself represents the surface of zero height.

Geomorphology (from Greek 'morph,' form). The explanatory science dealing with the form (shape) and surface configuration of the solid Earth (land and submarine relief features).

Geospatial information. Defined as information that identifies the geographic location and characteristics of natural or constructed features and boundaries on the Earth, including: statistical data; information derived from, among other things, remote sensing, mapping and surve~in~ techniques; and mapping, charting and geodetic data, including geodetic products. 05 )

Geosynchronous orbit. An orbit in which the satellite's orbital period is identical to the orbital period of the Earth. A geosynchronous orbit, unlike a geostationary orbit (with zero inclination, where the satellite motion relative to the Earth is at rest), does not impose any any restrictions on the orbit's eccentricity or inclination (see 0.12.2 on page 1268).

Gradiometry. Study of the spatial gradient of the Earth's gravitational field.

Grating. See diffraction grating.

Grazing angle. Angle between the instantaneously transmitted signal of an active sensor (a SAR) and the local horizontal of the target. In other words, the grazing angle = 90- 8, where 8 is the incidence angle. Grazing incidences occur usually at very shallow angles. It's like skipping stones across a stream (the rock will skip only if it glances off the surface at a small angle).

Gravity-gradient boom. A deployable extension of a space-craft (a rod fixed to the SIC with a small mass at its other end) intended to give the spacecraft elongated mass prop- Mass 2

erties to contribute to gravity-gradient stability (the con-cept was first successfully demonstrated by JHUIAPL on the Transit 5A-3 satellite with a launch on June 16, 1963). The principle: The attractive force F1 of mass 1 (satellite) about the common center of mass exceeds the attractive force F2 of mass 2. Hence, a torque arises to align the satel-lite to the vertical. - An elongated dumbbellshaped space-craft is the most gravity gradient stable configuration with the long axis oriented vertically in orbit, i.e. (usually) the smaller mass is always pointing toward the center of the Earth. The gravity-gradient torque, small even for LEO SIC, decreases with the cube of the orbital radius. In GEO, gravity-gradient stabilization can barely be achieved.

:/

Boom

Satellite center-of-mass

/ Orbit

0 / Mass 1

Fl

Earth

Many gravity-gradient stabilized LEO SIC use extendable booms to achieve a favorable moment-of-inertia distribution providing two-axis (pitch and roll) attitude control. The addition of an actuator, such as a momentum wheel, to a gravity-gradient stabilized SIC provides gyroscopic stiffness to passively stabilize the third (yaw) axis. The advantages of gravity-gradient stabilization are simplicity of control, long life and low power requirements.

2053)J. C. King, "Keynote Address to the ASPRS 2000 DC Annual Conference," PE&RS, Sept. 2000, pp. 1043-1053


Gravity wave (or gravitational wave). A wave disturbance in which buoyancy acts as therestoring force on parcels displaced from hydrostatic equilibrium.

Greenhouse effect. Refers to the trapping of heat from the sun by the atmosphere (mainly by its water vapor, which absorbs and reemits infrared radiation), in the same manner that the sun's heat is trapped by the glass walls of a greenhouse. The atmosphere, like the glass, is largely transparent to the sun's radiation, but it absorbs the longer wavelength radiation from the Earth's surface into which the sun's radiation is converted.

Greenhouse gases. Those atmospheric trace gases, such as water vapor, carbon dioxide, methane, and CFC's that are largely transparent to solar radiation but opaque to outgoing longwave radiation. Their action is similar to that of glass in a greenhouse. Some of the longwave (infrared) radiation is absorbed and reemitted by the greenhouse gases. The effect is to warm the surface and the lower atmosphere of the Earth.

Gridding. Use of a uniform system of rectilinear lines superimposed on imagery (such as photographs, mosaics, maps, charts, or other representations of the Earth's surface).

Ground pattern. Any specific identifying feature of the land surface which can be used for classification purposes.

Ground sampling distance (GSD). GSD is defined as the distance moved on the ground (in the along-track direction of the target area) during the integration period of the detector line array of an imaging instrument. Normally, the GSD is equated with the spatial resolution of a pixel or simply with IFOV (Instantaneous Field of View). However, this need not be the case. If the radiometric and electronic performance of a sensor allow, the GSD can be made smaller than IFOV to achieve better image quality because of the reduction of smear.

Ground track. Refers to the vertical projection ofthe actual flight path of a satellite (or aircraft) onto the surface of the Earth.

Ground truth. Reference data which is collected in the field (generally on or near the Earth's surface). The objective is to verify remotely-sensed primary sensor data against a typical 'reference.' Ground truth data is generally used in support of the analysis of remotely-sensed data. This ground truth may be gathered either by a single ground station, or by a network of ground stations (including buoys, remote terminals, etc.) whose data is collected by a 'data collection' satellite, or by airborne underflights of a spaceborne sensor. The ground reference that is being sought depends very much on the application. For instance, it may be a simple visual verification of the vegetation types in a particular scene, or it may be a particularly prepared ground patch with known radiative characteristics (reflectance, etc.) that is being used for the calibration of an airborne sensor. A very prominent ground truth station is for instance MOBY (see chapter P.139 on page 1731), which makes in situ measurements of ocean color near the Hawaiian island of Lanai.

Hall effect. Edwin H. Hall (1855 - 1938, American physicist) discovered what became known as the Hall effect in 1879 when investigating the nature of force acting on a conductor carrying a current in a magnetic field. Today, Hall effect measurements are used to characterize the electronic transport properties of semiconductors and metals. -In a model Hall effect measurement system, a uniform current density flows through a uniform slab of electrically conducting material in the presence of an applied perpendicular magnetic field. The Lorentz force then acts on the moving charge carriers, deflecting them to one side of the sample to generate an electric field perpendicular to both the current density and the applied magnetic field. The ratio of the perpendicular electric field to the product of current density and magnetic field is the Hall coefficient. The ratio of the parallel electric field to the current density is the resistivity. The Hall effect is also employed in Hall plasma thrusters (electric propulsion).

Heterodyning (see chapter 0.4)


High-pass filter (in optical sensors). An absorption filter pervious to electromagnetic radiation above a certain wavelength only.

Humidity. The water vapor content of air. The term is commonly used to mean "relative humidity," the dimensionless ratio of vapor that a given quantity of air can contain at a given temperature, expressed as a percentage. Perfectly dry air has a relative humidity of 0%; totally saturated air has a relative humidity of 100%.

Huygens's principle (Christian Huygens, Dutch physicist, 1629-1695). A very general principle applying to all forms of wave propagation which states that every point on the instantaneous position of an advancing wave/phase front may be regarded as a source of secondary spherical 'wavelets'. The position of the phase front an instant later is then determined as the envelope of all secondary wavelets. -This principle is extremely useful in understanding the effects due to refraction, reflection, diffraction, and scattering of all types of radiation. At his time, Huygens was the leading proponent of the wave theory of light.

Hydrological cycle. Virtually all the water of the hydrosphere is in constant circulation, moving through the hydrological cycle, a vast series of interchanges of geographic position as well as of physical state. Broadly speaking, the hydrologic cycle involves the transfer of water from the oceans through the atmosphere to the continents and back to the oceans. The processes involved are complex combinations of evaporation, transpiration, condensation, precipitation, runoff, infiltration, subterranean percolation, and others. The mean residence time of water in the atmosphere, on the land surface, and in the oceans is an important climate parameter.

Hydrometeors. These are cloud scatterers (when measured by a lidar or radar instrument) in different phases such as rain or frozen precipitation with a definite fall velocity.

Hydrosphere. All liquid and frozen surface waters (including the oceans, lakes and streams), groundwater held in soil and rock, and atmospheric water vapor. The Earth's total water budget is estimated at roughly 1.385 x 109 krn3. Over 97% of the Earth's total water supply is contained in the oceans and other saline bodies of water. Of the remaining 3%, a little over 2% is tied up in glaciers and ice caps and, along with atmospheric (0.001%) and soil moisture, is inaccessible. Hence, approximately 0.62% of the total amount of water may be regarded as 'freshwater' in rivers, lakes and groundwater supplies.

Hyperspectral. In remote sensing the term implies a spectral signature of narrow, continuous and contiguous spectral bands per pixel, i.e. a fine spectral resolution (A"A/"A = 1-5% ), over an extended spectral range. A hyperspectral sensor has a minimum of 20 spectral bands (normally 30-200 bands). On the other hand, "multispectral" usually implies fewer, spectrally broader bands, which may be noncontiguously spaced color bands per pixel. Hyperspectral imaging implies a hyperspectral signature for each pixel of the image. The detailed spectral information captured in a hyperspectral image allows detailed examination of the observed scene.

Image. Remotely sensed imagery (collected by CCD instrument, camera, or radar - in a wide range of the electromagnetic spectrum) is measured data which is transformed by numerical algorithms into an image. This is referred to as "computed imaging." 2054) An image is a two-dimensional grid of data; each of its elements is a pixel (picture element) whose coordinates are known and whose light intensity has a DN (Digital Number) value. The coordinates of the pixels and their DN values describe the image in terms of rows, called 'lines', and columns, called 'samples'. An 8-bit pixel provides up to 256 brightness levels (level 0 is set to black, while level255 is set to white); the brightness levels are also referred to as 'grayscale levels.' In 'false color image processing', those pixels which have the same DN value are assigned an arbitrary color. This enhancement technique is used, for example,

2054) Other forms of computed imaging (i.e. a restructured image of measured data) are in such fields as: tomography, x-ray crystallography, electron microscopy, seismic imaging, and radio astronomy.


to differentiate between various types of terrain or species of vegetation- to reveal changes which are otherwise not perceptible to the human eye.

Image correction. The adjustment of an image for errors: geometric, radiometric, etc.

Image correlation. The ability to locate or match a region of an image with a corresponding region of another image which can be taken with a different sensor at a different viewing angle.

Image degradation. Loss of resolution due to modulation transfer function defects including motion blur, nonlinear amplitude response, shading and vignetting and channel noise.

Image enhancement. The improvement of images to facilitate better interpretation (false color processing is an example), or further digital processing to develop a specific theme or to highlight certain features in an image series.

Image motion compensation. Algorithms (hardware and/or software) counteracting image motion during integration time, thereby reducing image blur. The blur effect increases when relative velocities of the sensor platform are noticeable with respect to the image integration time. The sensor platform attitude parameters are also important inputs for motion compensation. For low-flying aircraft motion compensation is normally in the forward direction. There are also algorithms in use for antenna motion compensation. For instance, the short -term scanning motion of the antenna is measured by IMU (Inertial Measurement Unit). This data is used as input to compensate the pulse-to-pulse phase of the radar to maintain coherence during synthetic aperture.

Image quality. Refers to the apparent central core size of the observed image, often expressed as an angular image diameter that contains a given percentage of the available energy. Sometimes it is taken to be the full width at half maximum (FWHM) value of the intensity versus the angular radius function. A complete definition of image quality would include measurements of all image distortions present, not just in size or projection. But this is frequently difficult to do, hence the approximations.

Image rectification. A process by which the geometry of an image area is made planimetric. Image rectification doesn't remove relief distortion or perspective distortion.

Image resampling. A technique for geometric correction in digital image processing. Through a process of interpolation, the output pixel values are derived as functions of the input values combined with the computed distortion. Nearest neighbor, bilinear interpolation and cubic convolution are commonly used resampling techniques. Image space. The mathematical space describing the position (coordinates) of pixels in the image.

Imaging array. A solid-state imaging array consists of a 1-D or 2-D set of photodetectors onto which an image can be focused, together with an integral electronic readout scheme. The devices are classified according to the particular readout scheme and detector type. A linear array is an imaging array consisting of a single line of detectors. The introduction of detector arrays has resulted in a new type of spectrometer- the imaging spectrometer- capable of generating images in much narrower bands (hyperspectral imagers) than was possible with conventional spectrometers.

Imaging sensors. Instruments that produce a 2-D image ofthe target area. Imaging sensor systems may by subdivided into 'framing systems' (such as camera or vidicon) and 'scanning systems.'

Imaging spectrometry. The simultaneous acquisition of images in many contiguous spectral bands.

Incidence angle. Angle formed between the instantaneous line of measurement of a sensor to a target and the local vertical of the target (or object).


Inclination. In general the angle between two planes or their poles; usually the angle between an orbital plane and a reference plane (i.e. the equator plane). Inclination is one of the standard orbital elements specifying the orientation ofthe orbit plane (see also 0.12 on page 1265).

Infrared radiation. Refers to electromagnetic radiation lying in the wavelength interval from 0. 7 1-1m to 1000 1-1m (or roughly between 1~-tm and 1 mm wavelength). Its lower limit is bound by visible radiation, and its upper limit by microwave radiation. Most of the energy emitted by the Earth and its atmosphere is at infrared wavelengths. Infrared radiation is generated almost entirely by large-scale intermolecular processes. The triatomic gases, such as water vapor, carbon dioxide, and ozone, absorb infrared radiation and play important roles in the propagation of infrared radiation in the atmosphere. -The phenomenon of infrared radiation was first discovered by the English astronomer Sir William Herschel (1738-1822) in 1800 (he dispersed the solar spectrum with a prism and found thermal effects of invisible radiation beyond the red).

In-situ soundings. An observation method (using sensors on such platforms as aircraft, balloons, ships, buoys, towers, spacecraft, on the ground, etc.) with the objective to measure parameters in the immediate environment. From a historical point of view 'in-situ' observation predated 'remote' observation by ages. Thermometers, barometers, thermocouples, hygrometers, air samplers, etc. are in-situ sensors, as are in fact most sensors in the fields of meteorology, atmospheric chemistry, hydrology, etc. By far the largest percentage of ground-truth observations are in-situ measurements (i.e., measurements of parameters at a particular location and at a particular time). Remote sensing data of a particular sensor and target area may be compared (calibrated) against in-situ data of that target area. Spaceborne data collection systems, like ARGOS on polar orbiting satellites, remotely collect data from many thousands of 'in-situ measurement systems' in the ground segment on a routine basis. Examples of spaceborne in-situ observations are: sensors measuring magnetic or electric field parameters, solar wind particles, etc.

By their very nature, in-situ measurements are local measurements; hence, they offer a very low observation efficiency with regard to coverage and timeliness (repeat periods). It would take a fleet of spacecraft to obtain in-situ data with sufficient spatial and timely resolution on a global scale.

Instantaneous Field ofView (IFOV). A term denoting the (angular) aperture within which the sensor is sensitive to electromagnetic radiation The IFOV may be expressed either as a small solid angle (in mrad or ~-trad, in this case the value is independent ofthe orbital altitude of the sensor), or as a unit area (e. g. 6 m x 6 m), or simply as the pixel size. Hence, the IFOV actually represents the spatial resolution of a sensor measurement.

Integration time. Refers to the short time period allocated for the radiative measurement of the instantaneous area of observation by the detector of a sensor (see also dwell time). Depending on sensor type the integration time may be very short [as is the case with electromechanical scanning systems which measure each individual cell (IFOV) across the swath sequentially], while the entire swath width (FOV) is measured by a CCD detector array in a single measurement.

Interference. Signals that arise from sources extraneous to the measurement system andresult in errors in the measured value.

Interference filter. A filter reflecting radiation selectively in a narrow spectral band.

Interferogram. An image of interference phenomena such as phase differences (as patterns of interference fringes) measured by an interferometer, FTIR spectrometers, or generated by SAR interferometry. Interference fringes form through the interaction of two beams. Hence, for a given wavelength, the signal on the detector is either strong or weak. Two cases are of interest:


• Constructive interference. This occurs when the optical path difference (OPD) between the two light paths from the collectors to the detector is zero or a multiple of the observing wavelength Destructive interference. It occurs when the OPD is a half-integer number of wavelengths. The destructive interference is also referred to as 'nulling mode'.

Interferometer. An instrument class for dispersing spectra. The technique determines the relative phase of two (or more) wave fronts as a function of spatial location by observing interference fringes. Radiation is split into two or more beams which traverse different path lengths. The beams are reflected by mirrors and recombined for interference analysis. (see chapter 0.10).

Interlaced scanning. Refers to a subsampling readout technique from a detector array of a camera or from some other high data-rate instrument. The advantage of such a measure is to reduce the bandwidth for image transmission. However, the disadvantage is a delay in total image recovery on the receiving side, resulting in distortions for fast moving objects in successive frames. The interlaced scanning technique is used for NTSC (National Television System Committee, a US TV display standard) television camera readout, in which each frame is scanned in two successive fields, each consisting of all the odd or all the even horizontal lines. The technique is also employed in other camera systems.

Intermediate frequency (IF). A common microwave frequency in an instrument (say, 80 MHz) for all channels at which considerable amplification takes place, interconnections are made, automatic gain adjustment is provided, and channels may be disabled upon command (squelch). The IF concept of a relatively low frequency is used to simplify the design of all functions compared to performing them at much higher frequencies in the GHz region.

Interplanetary magnetic field. Designates the magnetic field carried out from the sun by the solar wind, which permeates the entire heliosphere.

Intertropical conversion zone. A low pressure trough and minimum east wind, lying between the trade regions of the two hemispheres, that are nearly continuous around the world on climatological charts.

Inversion (atmosphere). A positive temperature gradient or increase in temperature with elevation, resulting in adverse conditions for the dispersion of pollutants.

Ionosphere. Layer of the Earth's atmosphere, between approximately 60 and 1000 km in altitude (a highly variable and complex physical system), that is partially ionized by solar x-rays, ultraviolet radiation, and energetic particles from space. The process of ionization is controlled by chemical composition and transport by diffusion and neutral wind. The region between about 160 to 1000 km, known as the F-region of the ionosphere, contains the greatest concentration of electrons (the peak electron concentration is around 250-300 km ). The presence of the ionized zone disturbs the propagation of electromagnetic waves, particularly at the lower wave frequencies. Below at certain frequency, the wave may be totally reflected by the ionosphere. -At times, the F-region of the ionosphere becomes disturbed and small-scale irregularities develop. When sufficiently intense, these irregularities scatter radio waves and generate rapid fluctuations (or scintillation) in the amplitude and phase of radio signals. The ionosphere was discovered in the early 1900s when radio waves were found to propagate "over the horizon." If radio waves have frequencies near or below the plasma frequency, they cannot propagate throughout the plasma of the ionosphere and thus do not escape into space; they are instead either reflected or absorbed. At night the absorption is low since little plasma exists at the height of roughly 100 km where absorption is greatest. Thus, the ionosphere acts as an effective mirror, as does the Earth's surface, and waves can be reflected around the entire planet much as in a waveguide.


Ionospheric disturbances. Refer to transient changes in ionospheric densities or currents, or the appearance of electron density irregularities, usually in association with the arrival of x-rays or UV bursts from solar flares.

Irradiance. Received radiative power per unit area (or the incident radiative flux onto a surface expressed in wm-2).

Isotropic radiator (antenna). A theoretical radiator of infinitesimal size in which it is assumed that all energy is distributed evenly (point source). Such a concept serves as a reference for other antennas of finite dimensions.

Lambertian radiator. A target or an object having the radiative property of directional independence of its (emitted and reflected) energy. With respect to reflection the object or target may be regarded to be a diffusely reflecting surface.

Langmuir probe. An instrument employed to measure the current-voltage characteristics of a plasma (single and double probes are in use) in order to determine plasma density.

Laplacian filter. A linear window operation (digital filter) concerning second derivatives of the pixel values within a window, either unidirectional or bidirectional (orthogonal).

Laser (Light Amplification by Stimulated Emission of Radiation). A source of light that is highly coherent (spatially and temporarily) and emitted in one or more wavelengths. A typicallaser consists of two essential elements: gain and feedback. A beam of light passing through the gain, or amplifying, medium stimulates it to release its stored energy in the form of additional light that adds to, or amplifies, the beam. Feedback is achieved by placing the gain medium within the resonator (a set of mirrors that reflects the beam back and forth through the gain medium). The light from such a laser is composed of a number of discrete wavelengths corresponding to different resonant frequencies, or modes, of the resonator. There are two groups of lasers which operate either in a pulsed mode or in a continuous mode. The spectral range of lasers extends from the UV to the TIR (90 nm to 12 ~m ). Types of lasers: 2055)

Gas lasers: Usually receive their energy input via collisions of gas atoms with high-energy electrons. This energy is provided by applying a high voltage between electrodes located within the gaseous medium. The most common types of gas lasers are:

He-Ne laser: Uses a gas discharge of helium and neon as the gain medium (this was the first laser to emit a continuous output beam). Argon and krypton ion laser: Uses a gas discharge containing ions as a gas medium. First lasers to operate in the blue and green regions of the spectrum. C02 laser: One of the most powerful lasers, operating mostly in the spectral region of about 10.5 ~m. They range from small versions with a few m W of continuous power to large pulsed versions. TEA (Transverse Excitation-Atmospheric pressure): These are generally pulsed C02 lasers; both the gas flow (about 1 atmosphere) and the electric discharge are transverse to the optical axis. Such conditions yield tremendous population inversions for short times. Commercially available TEA lasers deliver 100 to 200 ns pulses of several Joules/ pulse at a repetition rate of 50 Hz; they are used for welding and cutting.2056l Rare-Gas-Halide excimer laser: Operate primarily in the UV region in mixtures of rare gases, such as argon, krypton or xenon, with halide molecules such as chlorine and fluorine. Chemical lasers: In these lasers the molecules undergo a chemical reaction. The hydrogen-fluoride laser fits into this class.

• Metal Vapor lasers: These lasers are actually a type of gaseous laser, since the laser action occurs in the atomic or molecular vapor phase ofthe species. The two best -known types are the helium-cadmium ion laser and the pulsed copper vapor laser.

2055)Encyclopedia of Physical Science and Technology, Academic Press, 1987, Vol. 7 pp. 153-160 2056)Courtesy ofL. Zink of N1ST, Boulder, CO


Parameter Laser type Wavelength (nm) Energy range cw Argon Ion 488 and 514 1 ~W to about 1 W (Continuous Wave) He-Ne 633 1 ~W to about 20 mW

Diode 830 100 ~W to about 20 mW Nd:YAG 1064 100 ~W to about 450 W

1319 100 ~W to about 10 mW HeNe 1523 100 ~W to about 1 mW COz 10600 (or 10.6 ~m) 1 ~W to about 1 kW

Pulsed KrFExcimer 248 w-3 to about 200 mJ/pulse 50 ~ W - 9W average power

ArFExcimer 193 w-3 -3 mJ/pulse 50 ~ W - 3 W average power

Nd:YAG 1064 1 -50 mJ/pulse 10nW-100~W w-3- 10 nJ/pulse

Table 561: Overview of some laser characteristics 2057)

• Solid-State lasers: These laser generally consist of transparent crystals or glasses as "hosts" within which ionic species of laser atoms are interspersed or 'doped.' Typical host materials include aluminum oxide (sapphires), garnets, and various forms of glasses, with the most common lasing species being neodymium ions and ruby ions. -The energy input in these lasers is provided by a light source that is focused into the crystal to excite the upper laser levels. The light source is typically a pulsed or continuously operating flash lamp.

Nd:YAG laser: A laser whose gain medium consists of a neodymium-doped yttrium aluminum garnet crystal. The laser emits in the NIR region at 1.06 !liD. Ruby laser: This laser is produced by implanting chromium ions into an aluminum oxide crystal host and then irradiating the crystal with a flash lamp to excite the laser levels. Color center laser: This laser uses a different form of impurity species implanted in a host material (usually one part per ten thousand). Color lasers typically operate in the 0.8 - 4 !liD region and are tunable by using different crystals having different emission wavelengths.

• Semiconductor lasers: Semiconductor or diode lasers are the smallest lasers yet devised (about the size of a grain of salt). They consist of a p-n junction formed in an elongated gain region, typically in a gallium-arsenide crystal, with parallel faces at the ends to serve as partially reflecting mirrors. The light output of semiconductor lasers can be directly modulated using bias current, they can be tuned in wavelength using both temperature and bias current. Semiconductor diode lasers range in wavelength from 0.7 to 1.8 !liD with typically continuous output power of up to 10m W. Two types of semiconductor diode lasers are in wide use: 2058)

EEL (Edge-Emitting Laser). A horizontal-cavity laser with an optical output beam emitting from the edge of the laser chip.

VCSEL (Vertical-Cavity Surface-Emitting Laser). A VCSE~s cavity is perpendicular to the wafer plane (the beam is guided in the vertical direction). The VCSEL is used for wavelength engineering, in optical fiber communications, etc.

Quantum cascade laser (QC laser). 2059) Refers to a laser-based semiconductor sensor that operates at room temperature and at high power to detect minute amounts of trace gases (ppb) or pollutants by scanning for their optical-absorption "fingerprints.'' The lasers' high peak power, of 50-60 m W at 300 K, allows the use of uncooled detectors and enables LIDAR applications. They are particularly well suited for portable, robust sen-

2057) M. Dowell, "Pulsed-Laser Metrology at NIST," Optics&Photonic News, Feb. 2001, pp. 30-33 2058)C. J. Chang-Hasnain, "VCSELs Advances and Future Prospects," Optics & Photonics News, May 1998, pp. 34-39 2059) http://www .bell-labs.com/news/1997 /may/21/4.html


sors in applications such as the point detection of trace gases and remote sensing applications. The QC laser technology was invented by Jerome Capasso, Jerome, Faist, Sivco, Carlo Sirtori, Hutchinson and Cho of Bell Labs (Murray Hill, NJ) in 1994, who demonstrated continuously tunable, single-mode, QC distributed-feedback lasers operating at midinfrared wavelengths (5 and 8.5 (.lm) in pulsed mode. The single-mode tuning range is typically 50 nm in wavelength, and the peak powers are 60 m W. QC lasers are made using the technique of MBE (Molecular Beam Epitaxy), featuring layered structures of only a few atoms thick. The QC laser's emission wavelength is determined initially by quantum-confinement effects: the fact that its layers are so thin that electrons are squeezed and change their quantum-mechanical properties, allowing a range of possible wavelengths. The distributed-feedback lasers incorporate a grating that makes it possible to further refine the laser's wavelength, making them continuously tunable. - The operation of a QC laser is unlike that of other laser types. They operate like an electronic waterfall: when an electric current flows through a QC laser, electrons cascade down an energy staircase; every time they hit a step, they emit an infrared photon. At each step, the electrons make a quantum jump between well-defined energy levels. The emitted photons are reflected back and forth between built-in mirrors, stimulating other quantum jumps and the emission of other photons. This amplification process enables high output power. Bell Labs has built built QC lasers operating throughout the mid-infrared region from 4.5 to 11.5 (.till in both pulsed mode at room temperature and in continuous wave (CW) mode at temperatures up about 110 °C.

• Liquid (dye) lasers: Dye lasers are similar to solid-state lasers in that they use a host material in which the laser (dye) molecules are dissolved. Different dyes have different emission spectra or colors, thus allowing dye lasers to cover a broad wavelength range (320-1500 nm). A unique property of dye lasers is the broad emission spectrum (typical~ 30-60 nm) over which gain occurs. The dye laser is tunable over a frequency range of 10 3 Hz.

Dye laser: Laser in which the gain medium consists of an organic dye dissolved in a liquid solvent. Applications in areas where tunability of the laser frequency is required. Dye lasers are also used for producing ultra-short pulses, a technique which is referred to as 'mode-locking.'

• Free-Electron lasers: These lasers are significantly different from any other type of laser in that the laser output does not result from discrete transitions in atoms or molecules of gases, liquids, or solids. Instead, a high-energy beam (in the order of 1 MeV) of electrons is directed to pass through a spatially varying magnetic field that causes the electrons to oscillate in a direction transverse to their beam direction. This laser type can be used over a wide range of wavelengths from the UV to FIR.

Layman-alpha radiation. The radiation emitted by hydrogen at 1,216 A, first observed in the solar spectrum by rocket-borne spectrographs.

Leads. Leads are transient areas of open water and/or very new ice, created in response to convergence/divergence phenomena (deformation processes) in the polar ice pack (see also nil as).

Limb/Occultation sounding. A horizon-looking (or edge-looking i.e. outer edge of the apparent disk of a celestial body) observation technique that uses a distant object [(for occultation sounding) sun, star, or a sensor on another satellite in a different Earth orbit, (see Figure 363)] as a source to observe the signal on its path through the atmosphere that is essentially tangential to the Earth's surface. Two types of occultation techniques have been used in the past to determine the composition and structure of the atmosphere:

1) Extinctive occultations: These occur because atmospheric constituents absorb or scatter the incoming radiation. Since extinction cross sections are generally wavelength-de-


pendent, spectral measurements- as the star (sun) sets deeper into the atmosphereare diagnostic of the atmospheric composition. Hence constituent profiles may be determined from the relative transmission (i.e., the ratio of occulted to un-occulted spectraG. As a result, extinctive occultation measurements are self-calibrating and ideal for long-term trend monitoring. - The technique provides measurements that are commonly referred to as trace gas monitoring. Examples of spaceborne instruments employing extinctive occultations are: SAGE (AEM-2, ERBS, Meteor-3M, ISS), POAM (SPOT-3,4,5), HALOE (ATLAS-1,2), ATMOS (ATLAS-1, Spacelab-3), ILAS (ADEOS, ADEOS-11), and GOMOS (ENVISAT).

2) Refractive occultations: They occur because density gradients in the atmosphere lead to refraction of the incoming radiation, causing it to follow curved paths through the atmosphere. Relative measurements of the degree to which the path of the incoming radiation is changed provide the bulk of atmospheric properties (density, pressure, temperature). Usually, this occultation technique employs dual-frequency carrier phase observations of retarded signals (atmospheric propagation delays) from GPS or GLONASS satellites which permit the derivation of atmospheric profiles of density, pressure, and temperature. The GPS/MET instrument of Microlab-1 and TRSR (TurboRogue Space Receiver) of CHAMP, SUNSAT, and other missions are examples of refractive radio occultation monitoring.

Very long atmospheric paths (up to 4000 km) with high sensitivities or dynamic ranges can be obtained in this 'limb-sounding' configuration. The refractive technique takes advantage ofthe precise knowledge of GPS satellite' positions and timing of GPS radio signals. Instruments like GPS/MET and TRSR measure the extra time it takes for a GPS signal to enter Earth's atmosphere obliquely, pass through, and re-emerge to strike the LEO SIC -compared to an otherwise un-refracted direct ray path. The time delays of the GPS signal due to such atmospheric passage during the course of the occultation are used to derive the corresponding bending angles of the ray path, which in turn are converted to the refractive index profile of the atmosphere.

Some key advantages of limb sounding are:

It maximizes the reception of the signal emitted by the atmospheric layer at the viewed tangent height provided that the receiver antenna has a very narrow beam

• The background temperature (that of the deep space) is much colder than that of the atmosphere, which guarantees very low biasing of the measured atmospheric emissions Vertical profiles with a high resolution can be obtained by limb scanning with a very narrow antenna beam A global coverage is achieved with LEO polar orbiting satellites.

A major disadvantage of limb sounding is: Low horizontal resolution due to the measurement geometry (long path-length) and high speed of the spacecraft (signal integration along the moving tangent point).

Lithosphere. Earth's outer rigid crust composed of rocks rich in silicon, aluminum, calcium, sodium, potassium, and some other elements, and hence less dense than the underlying mantle. The lithosphere varies from less than 30 km thickness under the ocean to over 100 km under continents.

Local oscillator (LO). A receiver oscillator that produces a reference sinusoid for comparison with the noisy received sinusoid.

Look angle. The direction in which an antenna is pointing when transmitting and receiving from a particular cell (for an active instrument). Refers to the instrument pointing direction from nadir. -In the current literature the terms 'look angle,' 'illumination angle,' 'pointing angle,' 'off-nadir angle,' and 'viewing angle' all have the same meaning.


Looks (in SAR imagery) see chapter 0.8.4 on page 1252.

LORAN (Long-Range Navigation). A hyperbolic radionavigation system (the term 'hyperbolic' refers to the reflected ionospheric transmissions) which uses the difference in the time of arrival of signals from individual transmitters to establish position. Historically, LORAN was developed at MIT (DoD funded) during World War II as a navigation aid, known as LORAN-A The operation of LORAN-A was in the 1850-1950 kHz radio band. LORAN-A had a range of 1000 km. Later LORAN-B was developed to improve the accuracy of LORAN-A In 1958 LORAN-e became operational; it was used commercially formarine navigation. LORAN-e was transferred to civil authority (DOT) in 1974. Later, FAA extended LORAN -C coverage to include the continental USA - LORAN-e is a long-range (in excess of 1850 km), low-frequency (90 -110kHz) hyperbolic navigation system. Loran-e transmissions consist of groups of eight or nine accurately timed and phase-coded pulses at a carrier frequency between 90 and 110kHz. Each chain consists of a master and a number of slave transmitters.- In the mid 1960's LORAN-D (a low power transportable system with a range of 1100 km) was developed by the USAF.- Loran signals propagate as a ground wave, but sky waves reflected from the ionosphere are also received. - In the early 1990s, DoD declared that by the end of 1994, there would be no further military requirement for the system and authorized the transfer of LORAN-e assets to host nations for civil use. The USA plans to terminate Loran-e operations on Dec. 31, 2000.

A rebirth of LORAN-e in Europe was initiated in 1992 as result of an international agreement between the US and six European countries (Denmark, France, Germany, Ireland, theN etherlands, and Norway), known as NELS (Northwest European LORAN-e System). The NELS network, consisting of nine stations with a control center at Brest (France), started operations in 1999. The performance characteristics of the NELS network are: absolute location accuracy of 100-460 m; repeatable accuracy of20-100 m; availability per station of 99.9%; and availability per chain of 99.7%. A policy recommendation of IALA (International Association of Marine Aids and Lighthouse Authorities) states that the future use of radionavigation be based on complementary satellite and terrestrial systems. 2060)

Low Noise Amplifier (LNA). A preamplifier between antenna and receiver. It is usually attached directly to the antenna receive port. Its main function is to reduce the thermal noise of the received signal.

LOWTRAN. LOW-resolution TRANsmittance- a computer code (model of USAF Geophysics Laboratory, also referred to as AFGL, Hanscom AFB, MA) which predicts the atmospheric transmittance and thermal radiation emitted by the atmosphere and the Earth. LOWTRAN programs are applicable for wave numbers ranging from 350 cm·1 (28.5 ftm) in the infrared to 40,000 cm·1 (0.25 ftm) in the UV region. The LOWTRAN code calculates atmospheric transmittance and radiance, averaged over 20 cm·1 intervals in steps of 5 cm·1.

The succeeding models are more advanced, building on the capabilities and options of the previous LOWTRAN models. 2061)

LOWTRAN-2 (1972) • LOWTRAN-3 (1975)

LOWTRAN-3B (1976) • LOWTRAN-4 (1978)

LOWTRAN-5 (1980) LOWTRAN-6 (1983) includes solar/lunar scattering, new spherical refractive geometry subroutines, and an improved water vapor continuum model. Other modifications include a wind-dependent maritime aerosol model, a vertical structure aerosol model, a cirrus cloud model, and a rain model.

2060) U. Klinge, "A European Approach for an Integrated System- LORAN-C/Eurofix," Galileo'::; World, Vol. 1, No I, Winter 2000

206l)F. X. Kneizys, et al., ''Atmospheric transmittance/radiance: computer code LOWTRAN-6, Report AFGLTR-83-0187, Bedford, MA, NTIS Report ADA137786


• LOWTRAN-7 (1988). This code has been extended to include the microwave spectral region.

MODTRAN (1989)2062) (MODerate-resolution LOWTRAN). MODTRAN is an extended version of LOWTRAN-7 (six additional subroutines) to increase its spectral resolution from 20 cm-1 to 2 cm-1 (FWHM). Further objectives were: a) to model molecular absorption of atmospheric molecules as a function of temperature and pressure; b) to calculate band model parameters for twelve LOWTRAN molecular species; c) to integrate LOWTRAN-7 capabilities into the new algorithms, maintaining compatibilitywith the multiple scattering option. For MODTRAN, molecular absorption is calculated in intervals of 1 cm-1 bins, the other parts of the calculation remain unchanged. The molecular species affected are: water vapor, carbon dioxide, ozone, nitrous oxide, carbon monoxide, methane, oxygen, nitric oxide, sulfur dioxide, nitrogen dioxide, ammonia, and nitric acid. The MODTRAN spectral region is from 0- 17,900 cm-1 (with 2 cm-1 spectral resolution), calculations at larger wave numbers, i.e. the VIS and UV regions, are performed at the lower spectral resolution of 20 cm-1.

Magnetometer. An instrument for measuring changes in the Earth's magnetic field.

Magnetopause. The surface defining an interface between the magnetic field of a star and matter in the disk; a surface where the average magnetic pressure of the magnetic field is in pressure balance with the plasma pressure. Earth's magnetopause is the region in the ionosphere where the magnetosphere meets the solar wind (see Figure 408).

Magnetosphere. The region of space surrounding a rotating, magnetized sphere. Specifically, the outer region of the Earth's ionosphere, starting at about 1000 km above Earth's surface and extending to about 60,000 km (or considerably farther, such as 100 RE on the side away from the Sun).

Marginal ice zone (MIZ). The critical region in which polar air masses, ice, and water masses interact with the temperate ocean and climate systems (an important geophysical boundary zone involving energy exchanges). The transition zone is characterized by large horizontal gradients in the properties of the ice, ocean, and atmosphere.

Maser. An amplifier utilizing the principle of 'microwave amplification by stimulated emission of radiation.'

Measurement mode -duty cycle. The fraction of available time during which an instrument is actively performing Earth measurements and producing meaningful data, including incidental calibration and overhead (such as scan retrace). High data rate, high power consumption, and steerable instruments may have small duty cycles. Daylight -only instruments may have measurement mode duty cycles averaging 50 percent.

Medium Earth Orbit (MEO). Refers to all satellite orbits between LEO and GEO. MEO orbits have larger and longer footprints than LEO orbits. Navigation systems, like GPS and GLONASS, are examples of MEO orbits. MEO orbits are also attractive to a number of communication satellite networks due to their relatively small transmission delay times (in the order of 0.1 s ). The shorter radial distance (compared to GEO) translates into improved signal strength at the ground which means better reception and ultimately smaller terminals.

Mesosphere. Region of the atmosphere between approximately 50 and 85 km in altitude.

Meteoroid. A small particle in space (sources are comets, detritus from asteroid collisions, and interstellar dust). A meteoroid that survives the passage through the Earth's atmosphere and reaches the Earth's surface is known as a meteorite.

2062)A. Berk, L. S. Bernstein, D. C. Robertson, "MODTRAN: A moderate resolution model for LOWTRAN-7," AFGL-TR-89-0122, Air Force Geophysics Laboratory, Hanscom AFB, MA


Microwave radiation. Electromagnetic radiation generally considered to be in the wavelength range from approximately 1 mm to 1 m (three orders of magnitude). In microwave radiometry polarization is often used as a discriminant parameter, because microwave antennas are easily built with a single polarization direction. -(On the other hand, most optical sensors are relatively independent of polarization; a special effort must be made to polarize the signal prior to detection).- The largest portion of the microwave region is also the 'radar' region, hence both terms are used interchangeably (this also applies to the microwave instruments), see also 0.8.2 and 0.8.1.

Microwave rainfall monitoring. Microwave radiation with wavelengths in the order of 1mm to 3 em results in a strong interaction between the raindrops and the radiation (the drop size is comparable to the wavelength). Passive microwave data is helpful in locating the leading and trailing edges of rain areas (extent), however, the actual measurement of rainfall and rain rates provides unsatisfactory results. So far passive microwave systems function promisingly over sea surfaces but not satisfactorily over land surfaces. The general consensus is that a passive (multichannel and multipolarized radiometer)/active (radar) instrument complement can provide a better characterization of rain systems. Radar measurement of rainfall is based on Rayleigh scattering caused by the interaction of rain and the radar signals. The PR (Precipitation Radar) instrument on TRMM with a transmission frequency of 14 GHz (2.15 em wavelength) is expected to improve on the problem of rainfall measurement.

Microwave signal penetration. Most natural terrain materials, with the exception of water, are partially transparent to microwave frequencies. The energy of a (radar) wave incident upon a terrain surface is partially scattered back into the atmosphere; the remainder is transmitted across the boundary into the terrain medium.- The most important parameters governing the depth to which microwaves can penetrate natural materials such as soil, snow, or vegetation are the wavelength, the moisture content of the material (soil), and the shape and sizes of the scattering elements (such as the leaves in a vegetation canopy, or ice crystals on a snow surface). Radar observations in L-band (2-1 GHz) and P-band (1.0 - 0.3 GHz) frequencies are providing first results in penetration measurements, in particular with regard to soil moisture content and canopy penetration. -Note: The microwave permittivity of water is an order of magnitude higher than that of any natural dry material. 2063 )

Millimeter-Wave (MMW) region. Refers to the spectral region from 1 mm (300 GHz) to 10 mm wavelength (300 MHz ). The MMW region is part of the microwave region of the spectrum which extents conventionally from 1mm to 1 m wavelength. The MMW region is in particular of interest to radiometry (passive sensing) applications. Millimeter waves are able to penetrate many types of inclement weather, as well as opaque solids, and offers a lot of contrast. The emissivity of objects in this region is about 10 times higher that that in the infrared region. Submillimeter-wave (SMMW) region. Refers to the spectral region from 0.1 mm (3000 GHz or 3 THz) wavelength to 1 mm (300 GHz) wavelength. The SMMW is also being considered as part of the microwave region. SMMW observations are of particular interest to atmospheric science. Submillimeter-wave limb sounding has some advantages compared with limb sounding in other frequency ranges. In the UV and VIS region only daytime measurements are possible, while in the infrared region some important species like ClO and HCl are not detectable.

Modeling. An investigative technique that uses a mathematical or physical representation of a system or theory that accounts for all or some of its known properties. Models are often used to test the effects of changes of system components on the overall performance of the system.

2063) The penetration depth of microwaves decreases with increasing frequency. The atmosphere produces frequencydependent distortions which set an upper frequency limit due to attenuation. This limit is about 90 GHz for airborne radars and about 15 GHz for spaceborne radars.


Modulation. A process of manipulating the characteristics (usually frequency or amplitude) of a carrier in relation to another wave or signal.

Modulation Transfer Function (MTF). 2064l A function measuring the reduction in contrast from object to image (actually from each pixel), that is, the ratio of image-to-object modulation for sinusoids of varying spatial frequencies. The reason: any optical system reduces the contrast in the image compared to the contrast of the objects imaged; this is expressed as MTF. Thus, the MTF provides the response of an optical sensor as a function of object scene contrast and spatial frequency. MTF is also a measure of how accurately the actual radiance from a pixel (IFOV) is measured (a lower MTF indicates contributions from other pixels to the pixel of observation). A radiometrically accurate IFOV is one for which MTF >0.95.

Note: EIFOV (Effective Instantaneous Field of View) is defined as the resolution corresponding to a spatial frequency (ground resolution) for which the system MTF is 50%.

Moire Interferometry. A method to determine 3-D profile information of an object or scene, using interference patterns. Two identical gratings of known pitch are used. The first create a shadow of parallel lines of light projected on the object. The second is placed in the imaging train, then superimposed on the shadow cast by the first grating, forming a moire fringe pattern. Varying the gap between the lines changes the sensitivity.

Mosaic. An assemblage of overlapping airborne or spaceborne photographs or images whose edges have been matched to form a continuous pictorial representation of a portion of the Earth's surface.

Multilook technique. A technique of averaging a number of independent samples per pixel. applied to radar in order to reduce speckle.

Multiple access techniques. There are three basic multiplexing schemes that allow anumber of simultaneous transmissions over a single circuit. See also CDMA, FDMA, and TDMA in the glossary text. • Code Division Multiple Access (CDMA). Refers to an access scheme which employs

spread-spectrum modulations and orthogonal codes to share a communication link among its users. Frequency Division Multiple Access (FDMA). A process that shares a spectrum of frequencies among many users by assigning to each a subset of frequencies in which to transmit signals.

• Time Division Multiple Access (TDMA). A process that shares the time domain of a single carrier among many users by assigning to each time intervals in which to transmit signal bursts.

Multi path (GPS multi path). 2065) The term multipath is derived from the fact that a signal transmitted from a GPS satellite can follow a 'multiple' number of propagation 'paths' to the receiving antenna. This is possible because the signal can be reflected back to the antenna off surrounding objects, including the Earth's surface (land and/or ocean). Some characteristics of the multipath signal are: a) a multipath signal arrives always at a later time than the direct -path signal, b) a multi path signal is normally weaker than the direct -path signal due to the reflection loss, c) if the delay of the multi path is less than two PRN code chip lengths, the internally generated receiver signal will partially correlate with it. If the delay is > 2 chips, the correlation power will be negligible.

Multiplet. A spectrum line having several components.

Multispectral. In remote sensing the term implies two or more broad spectral bands in which a sensor detects radiation (see also Hyperspectral). The multispectral concept im-

2064) G. Joseph, "How well do we understand Earth observation electro-optical sensor parameters?" ISPRS Journal of Photogrammetry & Remote Sensing, Vol. 55, 2000, pp. 9-12

2065) B. Townsend, J. Wiebe, A. Jakab, M. Clayton, T. Murfin, ''Analysis of the Multi path Meter Performance in Environments With Multiple Interferers," ION GPS 2000, Salt Lake City, UT, Sept. 19-22, 2000, pp. 480-488


plies image analysis based on spectral characteristics. Note: The MSS (Multispectral Scanner System) sensor on Landsat -1 was probably one of the first spaceborne multispectral instruments with four spectral bands in VNIR.

Nadir. Direction toward the center of the Earth. Opposite of zenith.

Nilas. Thin and elastic ice sheets of a rather dull surface and up to a thickness of about 10 em. Nilas form in quiet sea water and bend easily in swells. Transverse pressure causes nilas to pile up. Leads may be frozen over by nilas; but nilas are not bound to be present in leads; they may also occur outside of leads.

Noise. Any unwanted or contaminating signal competing with the desired signal. In a SAR instrument, two common kinds of noise are additive, receiver noise and signal-dependent noise, usually additive or multiplicative. The relative amount of additive noise is described by the signal-to-noise ratio (SNR ). Signal-dependent noises, such as azimuth ambiguities or quantization noise, arise from system imperfections, and are dependent on the strength of the signal itself.

Noise-Equivalent-Equivalent-Width (NEEW) (sometimes shortened to 'noise-equivalentwidth'). A spectral resolution defining the smallest line area (in cm-1) that can be measured, or the equivalent area of the average noise bump.

Noise-Equivalent Flux Density (NEFD), sometimes also referred to as 'noise-equivalent irradiance.' Defined as the in-band entrance aperture irradiance on one pixel, from a point source, that equals the sensor rms noise (units are W/cm2). NEFD is related to a more familiar quantity, the Noise-Equivalent Radiance (NER), by the equation: NEFD = NERx pixel subtends (in steradians). NEFD can also be defined as the noise-equivalent power (NEP) per unit aperture area: NEFD=NEP/A.

Noise-Equivalent Radiance (NER). Defined as the in-band entrance aperture radiance (W/ cm2/sr) equal to the sensor rms noise. NER is the preferred figure of merit for an extended (pixel-filling) source. It is also defined as the noise-equivalent power (NEP) per unit aperture area, per pixel subtense (NER=NEP/NQ).

Noise-Equivalent Spectral Radiance (NESR). Defined as the radiance (W cm-2 sr-1 em+ 1) density that corresponds to the rms value of the spectral noise of a calibrated spectrum (or: the radiance change corresponding to SNR=1 ). NESR = NEP/ (~-txtxEx (t)172x Lla), with NEP =Noise Equivalent Power of the detector, 11 =modulation efficiency, t =optical efficiency, E = Etendue, t =scan time (1 instance), and Lla =spectral resolution.

Noise figure. Ratio of total output noise power of a system to that part of the output noise power due to the signal source.

Nonimaging sensors. Instruments which measure directly such quantities as radiant flux, irradiance, and radiance, which describe the intensity of a radiation field or the optical properties of a surface or a region of space. The sensors are nonimaging in the sense that they do not produce an image (a picture), but rather, integrate over time, space, and wavelength to produce a spectral curve, or a set of numbers that characterize the electromagnetic radiation. Typical measurement products are profiles, such as flux profiles, temperature profiles, moisture profiles, etc. Typical nonimaging instruments are: radar altimeters, sounders, scatterometers, spectroradiometers, radiometers, (note: there are also imaging radiometers which use scanning techniques, and imaging spectroradiometers using discrete filter-wheel systems), lidars, etc.

Nowcasting. The term is used in meteorology and refers to the development of atmospheric features on time scales between 0 and 3 hours over regional and local areas. Nowcasting is closely linked to very short-range-forecasting which covers developments over the time


scale of 3 to 12 hours over regional areas. 2066) A typical example of an application of nowcasting is severe weather incidents, where small-scale features undergo rapid development. Nowcasting requires the (almost) continuous monitoring ofthe area(s) of interest. Furthermore, as many of the features to be observed are fairly small, quite high spatial resolutions are needed.

Nyquist sampling rate (Henry Nyquist, a US physicist and a pioneer in the field of communication theory, was borne in 1889 in Sweden).2067)- Refers to a sampling rate above which a band-limited signal can be reconstructed from its sample value. If a signal s(t) contains no frequency components at or above fN Hz [ s(t) is then said to be band-limited to fN Hz], then s(t) can be completely reconstructed from its sample values, provided the samples are taken at a rate equal to or in excess offs = 2 fNsamples/s. This condition is known as the Nyquist or Shannon sampling theorem; fs is referred to as the Nyquist sample frequency, and fN is sometimes called the Nyquist frequency. The Nyquist theorem essentially states that the sampling rate must be twice that of the highest frequency to be represented.

Observational reference frames and models: Lagrangian experiments (Joseph Louis Lagrange, 1736-1813, French mathematician and physicist). Refer to a physical system that changes as time goes on from one configuration to another as it is progressing along a particular evolutionary path (path with the smallest result). In this concept observer and observed object have zero velocity relative to each other (Lagrangian coordinates are also referred to as 'material coordinates;' they do not vary with time). The strategy is to observe a reference volume (a cell of air) of interest as it moves through space. All measuring devices move along with the reference object. The concept is generally very complex with respect to instrumentation. Drifting buoys in the ocean or constant-pressure balloons in the atmosphere are Lagrangian-type experiments of relatively small complexity. Eulerian experiments (Leonard Euler, 1707 -1783). In Eulerian coordinates the properties of a fluid are assigned to points in space at a given time, without attempt to identify the individual fluid cells from one time to the next. The observer moves relative to the observed object. Example: observation of air masses. The vast majority of experiments, particularly in meteorology, are of the Eulerian type; a sequence of synoptic charts is a Eulerian data representation. Thansect experiments. The observer takes snapshot measurements by transecting a large reference volume into different directions. Example: an aircraft or a ship observes many different small-scale air masses as it moves through them.

Occultation. Distortion or interruption of a direct observation path between the observer (sensor) and a target by an intervening medium (such as an atmosphere or a celestial body). The occultation technique may for instance be used to study the Earth's atmosphere (or planetary atmospheres) by remote sensing (in a limb-viewing configuration). The atmosphere causes signal propagation delay and bending [between a transmitter (a GPS satellite) and a receiver (a GPS receiver on a LEO satellite)] due to the variation in the index of refraction in different shells of the atmosphere. -In the conventional sense, occultation refers to light path obstruction by an astronomical body, such as a star, by another astronomical body, as seen from Earth. In this context, a solar eclipse is the occultation of the sun by the moon.

Ocean color. The color of the ocean reveals information on the presence and concentration of phytoplankton, sediments, and dissolved organic chemicals. By studying the color of the light scattered from the oceans, optical sensors can quantify the amount of chlorophyll and other constituents in the various regions of the ocean. - Ocean color gives a quantitative measure of the spectral radiance of light reflected from beneath the ocean surface. Since

2066)"Meteosat Second Generation Programme Proposal," ESA!PB-EO (92), 57,9 November 1992, p. 14 2067) F. J. Taylor, "Digital Signal Processing," Encyclopedia of Physical Science and Technology,Academic Press, 1987,

Vol. 12. p. 600


phytoplankton dominates the optical characteristics of most ocean waters, it permits the estimation of marine plant biomass, ocean optical properties, and marine photosynthesis (primary production), see also 'chlorophyll.'

Ocean mixing. Processes that involve rates of advection, upwelling/downwelling, and eddy diffusion and that determine, for example, how rapidly excess atmospheric carbon dioxide can be taken up by the oceans.

Oceans of the world and climate. The oceans play a decisive role in the evolution of the climate. Through irradiation of the sun and exchanges with the atmosphere, they receive considerable quantities of heat, in particular at the intertropical latitudes, which they store due to their high thermal capacity, and which the ocean currents redistribute from the equatorial regions to the polar regions. - Current estimates account for 30-50% of the meridian transport which makes the climate of the middle latitudes more hospitable. Fluctuations in the circulation and elevation of the average sea level, under the combined effect of thermal expansion and the melting of the icepack, are indicators of climatic anomalies. - Thus, the world's oceans represent a major regulating factor of the climatic system. Their circulation and evolution must be understood (via satellite altimetry or other means of observation) to account for the climate variabilitv. Some figures of the oceans illustrate the importance of the oceans to our environment. 1068)

About 70% of the Earth's surface are covered with oceans, this amounts to a total area of360 x 106 (million) km2, the total ocean volume is estimated to be 1.46 x 109 (billion) km3; hence the total mass is about 1.46 x 1018 metric tons. The average depth of the oceans is about 3800 m

• The mass of the oceans is about 300 times larger than the mass of the atmosphere; the heat storage capacity of the oceans is 1200 times the heat capacity of the atmosphere; the oceans provide 70 times the carbon storage capacity of the atmosphere. See also "altimetry" and "hydrosphere" in the glossary.

In addition to the normal ocean-atmosphere heat exchanges, the winds blowing on the sea surface, contribute to the productions of surface marine currents. These currents travel much more slowly than the winds; however, these ocean currents can store a large quantity of heat. This property enables the ocean to stabilize the Earth's temperature. An example of such an ocean current is the Gulf Stream which forms in the west Atlantic seaboard (mainly in the Gulf of Mexico) and travels in the direction of northern Europe.

Omega. A long-range, worldwide, all weather, day and night radionavigation system operating in the VLF (Very Low Frequency) band of the radio spectrum. The Omega network consists of eight atomic-clock-controlled transmitters transmitting sequentially on assigned frequencies between 10.2 and 13.6 kHz. The Omega network transmitters are located in Argentina, Australia, Japan, Liberia, Norway, Reunion, and USA (Hawaii and North Dakota). Users of Omega are commercial airlines, ships, land vehicles, meteorology (tracking of balloons), etc. Omega, like LORAN, uses phase differences of continuous-wave radio signals. The receiver of a user synchronizes to the transmitter frequency and measures the phase relationship of the receiver's location. Two or more 'line-of-position' measurements define the receiver location. Omega (of World War II vintage, developed by the USA) provides positioning within 2 to 4 nautical miles at a 95% confidence level with 95% availability. -The USA terminated permanently its Omega operations on Sept. 30, 1997.

Operational sensor. In Earth observation an instrument is said to be "operational" if the following services are provided: continuity of observations, timeliness of data delivery to the costumer, and several usable data products. A number of environmental/meteorological missions, like NOAA/POES and GOES, the METEOSAT series, etc., with their major instruments (AVHRR, etc.) and services, are considered "operational." Routine service

2068) http://www .cnes.fr/WEB _ UK/activi ties/programmes/Topex/top _posd.html


provision and regular use of the data by a user community are key ingredients for operability.

Optical depth. Refers to the negative logarithm ofthe extinction [In I/I0 ], where I is the radiation intensity at the back plane of the absorbing medium, and 10 the incident intensity. The optical depth is the product of the extinction coefficient, the density of the medium, and the length of the transmitted medium layer (Lambert Beer Law).

On-orbit electric propulsion systems. (see chapter 0.14)

Optical spectrum. Refers to electromagnetic radiation of frequency (or wavelength) that can be focused, dispersed, and detected using optical components such as lenses, mirrors, and gratings. This includes more than the narrow visible region; in general terminology the optical spectrum extends from 0.01 to 1000 !!ill (UV to FIR inclusive).

Optoelectronics.2069l The term is a contraction of 'optical electronics' and refers to the photon effects (interaction/conversion, transmission) with a medium and vice versa. Optoelectronics is one of the foremost research fields affecting many areas of solid-state computer technology [microprocessors, data storage, communication (photon guidance between a source and a detector, optical fibers for signal transmission in optical communication, lasers), visual display methods using LEDs (Light Emitting Diode) and LCDs (Liquid Crystal Display)], energy detection and conversion [photon conversion into electrical energy (photodetection, photovoltaics), etc.]. Optoelectronics has also a wide filed of applications in imaging sensor design. Note: Often the terms electro-optical, electrooptical, and electrooptics are used with the identical meaning of optoelectronics. From a detection standpoint, the term optoelectronics seems to be more logical, because a detection sequence goes from the optics to the electronics.

Optoelectronic devices. Refer to systems in which the photon, the basic unit of light, is affected. There are four basic groups of optoelectronic devices:

Photodetectors and solar cells - that convert photons into an electrical current Light-emitting diodes (LEDs) and semiconductor lasers- that convert an applied voltage into emitted photons

• Optical +s -that guide light between a light source and a detector • Liquid-crystal displays - that use an applied voltage to change the reflection of light.

Optoelectronic detection (pushbroom scanner). The scanner uses a line detector to scan the cross-track direction of a scene, the total field of view is detected (imaged) simultaneously. The number of pixels is equal to the number of ground cells for a given swath. The motion of the platform (airborne or spaceborrur) provides coverage in the along-track direction. When a 2-D line detector is used (several lines of detectors in the cross-track direction), then one dimension (cross-track) represents usually the spatial dimension, while the other is used for different spectral bands (multispectral imaging). Examples of push broom scanners are: HRVon SPOT series of CNES, LISS on the IRS satellite series of ISRO, AVNIR on the ADEOS SIC of NASDA, MSU on the RESURS series of Russia, ALI of the E0-1 satellite ofNASA. ·.

Optomechanical detection (whiskbroom scanner). A form of radiation detection, employing an oscillatingw rotating mirror to a line-scanning whiskbroom scanner. On-axis optics or telescopes.with.scan mirrors sweep from one edge of the swath to the other. The FOV of the scanner can be detected by a single detector or an along-track line-detector. Typical examplesof optomechanical scanners are: TM and ETM + of the Landsat series, AVHRR on the NOAA/POES series, SeaWiFS on Orbview-2 (formerly named SeaStar), ASTER and MODIS of the Terra satellite.

2069) Special issue.on Optoelectronics Technology, Proceedings of the IEEE, Vol. 85, No. 11, November 1997


Laser scanners (i.e. active lidar systems) utilize also optomechanical scanner assemblies just as many multispectral whiskbroom scanners. However, as active sensing systems, they are using a laser beam as a sensing carrier. Two optical beams must be considered, namely the emitted laser beam and the received portion of that beam.

Orbit types and terminology. See chapter 0.12 on page 1265.

• LEO (Low Earth Orbit) • MEO (Medium Earth Orbit)

HEO (Highly Elliptical Orbit) GEO (Geostationary Orbit) Sun-synchronous orbit

Orographic phenomena. Meteorological events (precipitation, special winds, clouds, fronts, etc.) associated with the disposition and character of hills and mountain ranges (distribution effects the linked to the form of the terrestrial relief). Orographic precipitation results from the lifting of moist air over an orographic barrier; however, it is not limited to the ascending ground, but may extend for some distance windward of the base of the barrier. Orographic lifting refers to the deflection of an air current up and over mountains. Examples of orographic winds are: Fohn, Mistral, Bora, Santa Ana.

Orthographic projection. A projection in which the projecting lines are perpendicular to the plane of projection (also referred to as orthogonal projection).

Orthophotography. A digital orthophoto is a raster image, which has been accurately scanned and rectified with the aid of geodetic surveying and photogrammetry.

Orthorectification. ( orthorectified imagery)

Ozone. A molecule made up of three atoms of oxygen (03). Ozone strongly absorbs UV radiation in the wavelength range of 290 - 300 nm. In the stratosphere, it occurs naturally and provides a protective layer (ozone layer between -12-30 km in which ozone is relatively concentrated > 1012 molecules/cm3) shielding the Earth from ultraviolet radiation and subsequent harmful health effects on humans and the environment. In the troposphere, it is a chemical oxidant and major component of photochemical smog. Ozone is an effective greenhouse gas especially in the middle and upper troposphere and lower stratosphere. -The depletion of ozone in polar latitudes is attributed to a sequence of chemical reactions involving chlorine and bromine compounds. These sources are simple organic compounds containing chlorine, e.g. chlorofluorocarbons (CFCs), and/or bromine (e.g. halogens). Nearly all of the chlorine and about half of the bromine in the stratosphere originates from human activities.

Paleoclimatology.2070) Science which deals with past climate periods of the Earth in very large space-time scales. Long-term baselines of past climate changes are studied and reconstructed to understand climate processes and predict future climate change (climate models). Paleoclimate data are derived from ice cores, tree rings, marine and lake sediments, fossil pollen, plant macrofossils, paleovegetation, past sea surface and lake level data, terrestrial ice sheet height and extent, land surface properties, etc.

Panchromatic channel. A channel of a sensor-detector system which covers the entire width of a spectral range, in particular the visible range (VIS).

Parallax. Apparent change in the position of an object due to an actual change in the point of view of observation. Example application: In optical stereo observation the parallax between two images, viewed from different angles, is used to derive the third dimension of altitude. This topographic information is used for map-making.

2070) D. M. Anderson, R. S. Webb, J. T. Overpeck, B. A. Bauer, "The NOAA Paleoclimatology Program," NOAA Earth System Monitor, Vol. 3, No.3, March 1993, pp. 6-8


Particle precipitation. Refers to the release of charged particles, stored in the Earth's magnetosphere, into the atmosphere. The particles follow magnetic field lines. They cause a glow (creating an aurora) when they strike the atoms of the upper atmosphere.

Passive sensor. A sensing system that detects or measures radiation emitted by the target. Such sensing systems do not emit any power to the target for purposes of measurement. Hence, passive sensors are sensitive to radiation of natural origin, usually reflected sunlight or energy emitted by an object. Examples of passive sensors are: cameras, multispectral scanners, and radiometers.

Peltier effect coolers. They work on the principle of the thermoelectric effect. Such coolers are thermodynamically reversible low impedance devices, operating at a high current from a DC power supply. A single stage cooler can typically achieve a temperature of -40°C, and lower temperatures can be achieved using several stages. A six stage device may achieve -100 o C and give a cooling power of around 1 m W at -80 o C. Peltier coolers are by their very nature vibration-free.

Perigee. The point in an orbit at which the spacecraft is nearest to the Earth.

Phase modulation (PM). Angle modulation in which the phase of a sine wave carrier is caused to depart from the carrier phase by an amount proportional to the instantaneous value of the modulating wave.

Phased-array technology. Phased arrays are random-access devices (antennas) employed for electronic beam-steering applications in the microwave and/or optical regions of the spectrum. The technology of electronic beam-steering overcomes many limitations of mechanical beam steering (in particular the motion of masses), offering such capabilities as very precise stabilization ( < ~rad), rapid random-access pointing over a widefield of regard (inertialess steering of beams), programmable multiple simultaneous beams, and other capabilities. In an active phased array system (such as a microwave antenna) individual transmit elements form and direct a beam into a particular direction (2-D steering). The field intensity across the aperture of an active microwave array is generally tapered at the edges to achieve low sidelobe levels. In some radar (SAR) applications the phased array concept is also referred to as ScanSAR with the capability to extend the regular swath width (see also phased-array antenna under antenna).

Photodetector. A semiconductor device that transforms radiation (light) into an electrical signal. There are two basic types of photodetectors: photodiodes and photoconductors.

Photodiode. Refers to a semiconductor diode which receives incident radiation thereby becoming a photodetector. Principle of operation: Photons (energy) incident on the photodiode (p-n junction) form electron-hole pairs in the detector material (silicon, for instance) when they are absorbed. Manipulation of the electron-hole pairs produce an output signal proportional to the amount of energy received. The time-varying signal represents the total amount of energy it receives. An important measure of how well the device converts photons to electrons is the quantum efficiency (QE). - Silicon is virtually transparent to radiation in theIR range. However, in the UV and VNIR range (0.2- 1.1 ~m), radiation has enough energy (i.e. photon absorption can take place) to create electron-hole pairs.

Photoelectric cell (or photocell). A detector (transducer) which converts electromagnetic radiation from the UV, VNIR regions of the spectrum into electrical quantities such as voltage, current, or resistance.

Photogrammetry. A remote sensing application using image surveys (initially photographs) from airborne sensors and producing (topographic) maps from these images (along with position data). The ASPRS definition is: "Photogrammetry is the art, science and technology of obtaining reliable information about physical objects and the environment through processes of recording, measuring, and interpreting photographic images and patterns of

1358 Appendix A: Glossary --------------------------~

electromagnetic radiant energy and other phenomena." 2071)

In the past, spacebome imagery was not (or hardly) used for map making due to insufficient spatial resolution; this certainly changed with the availability of high-resolution imagery (<3m) starting from about 1998. Spatial imagery resolutions from satellites are classified as:

• Very low: for pixel sizes greater than or equal to 300 m • Low: for pixel sizes between greater than or equal to 30 m and < 300 m

Medium: for pixel sizes between greater than or equal to 3 m and <30m High: for pixel sizes between greater than or equal to 0.5 m and <3 m

• Very high: for pixel sizes <0.5 m

Photomultiplier. A photoemissive detector in which amplification is obtained by secondary emission.

Photon. A particle description of electromagnetic radiation, which can exhibit the behavior of either waves or particles.

Photosphere. Refers to the layer surrounding the sun from which visible light is emitted into space.

Photosynthesis. The conversion of inorganic matter into organic matter by plants, using light as the energy source. Light energy absorbed by chlorophyll is used to manufacture carbohydrates (sugars) and oxygen from carbon dioxide (COz) and water. Photosynthesis is dependent upon favorable sunlight, temperatures, plant nutrients, and additionally, on soil moisture and carbon dioxide concentration for terrestrial plants. Increased atmospheric levels of carbon dioxide can increase photosynthesis in many land plants. Photosynthesis is responsible for the generation of all atmospheric oxygen. The photosynthetic generation of organic matter is also called 'primary production.'

Photovoltaic effect, photoconductive effect. Refers to the direct conversion of radiation into electrical energy. The photovoltaic effect is achieved when a photon-produced electronhole pair is separated by a space charge field (p-n junction diode) thus producing a photocurrent. Solar cells are photovoltaic devices. The photovoltaic effect was first reported by the French scientist Edmund Becquerel in 1839. He observed a voltage between two electrodes in a beaker of electrolyte when the beaker was exposed to sunlight. - The photoconductive effect occurs when a bias voltage is applied across a uniform piece of detector material. The photocurrent is then proportional to the density of electrons excited into the conduction band by the incoming photons.

Phytoplankton. The assemblage of microscopic algae (diatoms, flagellates, etc.) in aquatic ecosystems that drift passively with currents (plankton = wandering). The "grass" of the sea, upon which virtually all marine life depends (see also chlorophyll).

Pixel (Picture Element). The smallest area unit of an image which is generated by a single digital measurement (see also image). A pixel has a unique position within an image raster. Its numerical value is taken artificially from complete or partial resolution cells, sometimes also referred to as 'image point.'

Pixel value. The digital radiation value of a pixel, expressed as a digital number (DN) or digital count (DC), radiance value, reflectance or other radiation value.

Planetary albedo. The fraction of incident solar radiation that is reflected by a planet and returned to space. The planetary albedo of the Earth-atmosphere system is approximately 30%, most of which is due to backscatter from clouds in the atmosphere.

Planetary Boundary Layer (PBL). Defined as the atmosphere between the Earth's surface and the free atmosphere. It is directly affected by the properties of the Earth's surface and

2071)E. M. Mikhail, "Is Photogrammetry still Relevant?," PE&RS, Vol. 65, No 7, July 1999, pp. 740-751


surface forcings, such as frictional drag, evapotranspiration, heat transfer, pollutant emission, and topography. See also Atmospheric Boundary Layer.

Plasma. A completely ionized gas (a low-density gas), the so-called fourth state of matter (besides solid, liquid, and gas) in which the temperature is too high for atoms as such to exist. A plasma is an electrically neutral gas consisting of charged particles such as ions, electrons, and neutrals. While the temperature of a plasma is very high, its density is very low.

Plasmoid. Bubble of plasma. Refers to the merging of magnetic lines in the magnetotail which is thought to produce a bubble of plasma, called a plasmoid that flows down the tail during active solar periods.

Polarimetry.207Z) Polarimetry deals with the vector nature of polarized electromagnetic radiation throughout the frequency spectrum. The electromagnetic field is a traveling wave (at the velocity of light) with electric and magnetic vector fields perpendicular to each other and to the direction of wave travel. A change in the index of refraction (or permittivity, magnetic permeability, and conductivity) causes the polarization state of a single frequency wave to be transformed, i.e. to be repolarized. Hence, a reflected (scattered) polarized wave from an object such as a radar target must contain some innate information about the object. The interpretation of the behavior of these complex signatures (in particular the direction of the electric field vector of the reflected polarized radiation) is in effect a major objective in polarimetry. In remote sensing polarization measurements are mostly performed in the microwave region of the spectrum. The incorporation of coherent polarimetric phase and amplitude into radar signal and image processing is indeed very promising.

Polarization. Defines the spatial orientation or alignment of the electric (and magnetic) fields of an electromagnetic wave (radiated by an antenna). Horizontal (H) I vertical (V) polarization refers to the electric field (magnetic field) vector's being parallel I normal to the surface of the medium that the wave is incident upon.

Like polarization: HH or VV (one component for the transmit and one for the receive signal, as is the case for active sensors) Cross polarization: HV or VH. Cross polarization requires multiple scattering by the target and therefore results in weaker backscatter than like polarization. Alternating dual polarization: alternate transmit and/or receive polarization so that two polarization combinations are measured - e.g. HH and HV or HH and VV

Polarization is established by the antenna, which may be adjusted to be different on transmit and on receive. Reflectivity of microwaves from an object depends on the relationship between the polarization state and the geometric structure of the object. Possible states of polarization in addition to vertical and horizontal include all angular orientations of the E vector, and time varying orientations leading to elliptical and circular polarizations.

Polarization knowledge offers an additional capability in detecting object characteristics and in discriminating between them, especially in the microwave region of the electromagnetic spectrum (for passive and active sensors). See also Radar polarimeter.

Although VV, HH, VH, HV are common terms in "polarimetric radar," the generally accepted terms differ in polarimetric radiometry. Here, the four scalar brightness temperatures are used that make up the complete (modified) Stokes' vector: Tv= I Ev 12, Th= I Eh 12, Tu=2Re (TvTh *},and Ty=2Im (TvTh *}. 2073) The modified Stokes vector is related to the (unmodified) Stokes vector as follows: T 1 = (Tv+ Th)/2, Tz =(Tv -Th)/2. Some authors use T3 and T 4 in place ofT u and Tv to eliminate confusion between the vertical (v) and fourth Stokes parameter (V) indices.

2072) W-M. Boerner, H. Mott, E. Liineburg, et al., "Polarimetry in Remote Sensing: Basic and Applied Concepts," Chapter 5 (94 p) in R. A. Reyerson, ed., The Manual of Remote Sensing, 3rd edition, ASPRS Publishing, Bethesda, MD, !997

2073) Courtesy of AI Gasiewski of NOAAJETL in Boulder, CO


Polar vortex. Refers to the swirling mass of air that appears each year over the Earth's poles.

Polynya. Polynyas (like leads) are openings in polar region sea ice, they range in size from a few hundred meters to hundreds of kilometers. Polynyas may be formed by two mechanisms: a) forming ice may be continually removed by winds or currents (an example is a shore polynya with offshore winds), b) oceanic heat may enter the region in sufficient quantity to prevent local ice formation.

Precision. The precision of a measurement is a measure of the reproducibility or consistency of measurements made with the same sensor. (The effect of random errors can be reduced by repeated measurement or by averaging, which increases the precision of a measurement).

Preprocessing. Commonly used to describe the correction and processing of sensor data prior to information extraction. For imaging data preprocessing includes geometric and radiometric correction, mosaicking, resampling, reformatting, etc.

Primary productivity. The rate of carbon fixation by marine photosynthetic organisms (phytoplankton). Primary productivity results in the reduction of dissolved inorganic carbon to form organic carbon, with concomitant release of oxygen.

Pseudolites. Refer to auxiliary ground-based transmitters that broadcast GPS-like signals to supplement those generated by the satellites. The transmitters were initially called "pseudo-satellites," which was abbreviated to "pseudolites." System developers used pseudolites as direct replacement for satellites that had not yet been launched, to facilitate system tests. A pseudolite transmits a signal with code-phase, carrier-phase, and data components with the same timing as the satellite signals. A GPS receiver acquires this signal and derives its measurements to be used in a navigation algorithm. Applications are particularly useful for equipment (receiver) tests for such functions as fault detection and isolation, for pseudorange correction (identical to DGPS), and many other practical solutions. 2074) 2075)

Pseudorandom Noise (PRN). Refers to deterministic binary sequences which are used in spread spectrum communication systems and in ranging systems such as GPS and GLONASS. Two PRN codes are continuously broadcast by GPS satellites: the CIA code and the P-code, both codes modulate the navigation signals. The modulation appears to be random but is, in fact, predictable; hence the term 'pseudorandom'. The PRN technique allows the use of a single frequency by all GPS satellites and also permits a broadcast of a low-power signal. [Note: The PRN technology was first employed in the 1950s by radio astronomers. With them researchers were able to measure the time delay in the weak radar reflections from the surface of a distant planet- by finding the instant, when the received signals and the transmitted PRN sequences seemed to match most closely.]2076)

Pseudorange. Refers to the range between the antenna phase centers of a GPS satellite and a receiver, measured by the receiver's delay-lock loop using the C/A-code or P-code. The range is biased by the offset of the clock in the receiver from that in the satellite and by atmospheric propagation delays.

Pulse Code Modulation (PCM). Any modulation that involves a code made up of pulses to represent binary information. This is a generic term; additional specification is required for describing particular cases.

Quantization. The process of converting continuous values of information to a finite number of discrete values. A 10 bit quantization means that the measured signal can be represented by a total of 1024 digital values, say from 0 to 1023.

2074) S. Cobb, M. O'Connor, "Pseudolites: Enhancing GPS with Ground-based Transmitters," GPS World, March 1998, pp. 55-60

2075)1. M. Stone, et al., "GPS Pseudo lite Transceivers and their Applications," Proceedings of! ON National Technical Meeting, San Diego, CA, Jan. 25-27, 1999

2076)T. A. Herring, "The Global Positioning System," Scientific American, Feb. 1996, pp. 32-38


Quantum efficiency (QE). A measure of the efficiency with which incident photons are detected (such as a photodiode). Some incident photons may not be absorbed due to reflection or may be absorbed where the electrons cannot be collected. The QE is the ratio of the number of detected electrons divided by the product of the number of incident photons times the number of electrons each photon can be expected to generate. Visible wavelength photons generate one electron-hole pair. More energetic photons generate one electronhole pair per each 3.65 eV of energy.

Radar (Radio Detection and Ranging). A method, a system, or a technique for using beam, reflected, and timed electromagnetic radiation to detect, locate, and track objects, to measure distance (range), and to acquire terrain imagery (see also chapter 0.8.2). The term 'radar' in remote sensing terminology refers to active microwave systems (from about 1 GHz-100 GHz; most current instruments operate below 10 GHz). The terms 'Doppler delay' (range), 'Doppler gradient' (range rate), and 'Doppler frequency analysis' are important parameters in the formulation of the range-Doppler radar imaging principles. The motion of the sensor-bearing vehicle provides the relative motion between sensor and target required to perform imaging.

Radar systems may be classified by the signal measurement technique employed - there is the pulsed radar class and the FM/CW (Frequency Modulation/Continuous-Wave) radar class. The pulsed radar is the most widely used type of radar systems. It is so called because the transmitter sends out pulses of microwave energy with relatively long intervals between pulses. The receiver picks up the echoes of the returned signals; the elapsed time (or run time) is a measure of the distance travelled.

FM/CW radar transmits continuous microwave energy- the resultant continuous echo cannot be associated with a specific part of the transmitted signal (hence, range information cannot be obtained). However, the system can determine the speed of a target by measuring the Doppler shift (change in frequency). A more sophisticated continuous-wave instrument, known as 'frequency-modulated radar,' is also able to measure range. This is done by tagging each part of the transmitted microwave signal (by continuously changing the frequency), rendering it recognizable upon reception. With the rate of frequency change known, the difference in frequency can be interpreted as a range measurement.

Radar instruments consist of the following major elements: RF electronics, antenna,digital electronics, and recorder. Radar instruments are built for a specific transmission frequency in the microwave spectrum, such asP-band, L-band, S-band, C-band, X-band, Ka-band, etc.; some very advanced instruments offer observation in multiple frequencies.

RAR (Real-Aperture Radar). The term RAR is used because the along-track resolution of a surface image is determined by the actual length of the antenna aperture. In general, the larger the aperture of the antenna (in terms of wavelengths), the narrower will be the beam (along-track resolution is given by the width of the antenna sweep; across-track resolution is determined by the range-resolving capability of the instrument). RAR systems are usually much simpler than SAR systems in design and data processing. RAR-pulsed signals, based on the range-Doppler principle, are not required to be coherent (only the signal amplitude information is recovered and processed), representing and displaying backscatter characteristics from the surface sweep that are recorded on film or on magnetic tape. Microwave energy reflected from the surface terrain (target) is converted by the RAR instrument into electrical signals and recorded as a function of distance (along-track and across-track direction). The radar returns from the different positions in the sweep (and at the different ranges) are separated in time by the radar receiver (the across-track range measurement is a function of signal return time). After reception and recording of the previous pulse, a new pulse is transmitted for a new radar sweep.- The density of the image varies with the surface properties (roughness, moisture content, etc.). The image can be interpreted in terms of the topographical features of the terrain.


• SAR (Synthetic Aperture Radar), see also 0.8.2. This radar type permits high-resolution imagery at long ranges (a SLAR device from a satellite orbit is of limited use due to the poor resolution obtained by the angular geometry constraints of the radar beam). A SAR instrument is also referred to as a 'coherent SLAR.'- SARis a concept for complex signal processing techniques to recover an image by the coherent processing of all return signals of all targets (cells) in a single sweep. The cross-track Doppler range of all targets is determined by the signal return time. The pulse bandwidth determines the cross-track or range resolution. Coherence 2077) in this SAR context refers to the fact that the phase as well as amplitude information of the radar cross section is measured for all recovered signals. The SAR technique provides resolutions that would normally be associated with an antenna with an aperture far wider than that actually used. - A disadvantage of the SAR observation/processing technique is the generation of very high data rates (between 20 and 100 Mbit/s and more); this implies high communication rates and large storage volumes. On-board recorders are strained to their very limits to handle SAR data. First attempts are being made at real-time on-board preprocessing for the purpose of data reduction. The main elements of a SAR instrument are:

RF electronics. The RF portion of a SAR system consists of signal generators, high power transmitters (single or combined), low noise receivers, and the associated signal conditioning elements: amplification, filtering, and frequency conversion. Important RF characteristics to a SAR instrument are: large dynamic range with good linearity and low noise floor, good amplitude and phase stability over time and temperature, and high power efficiency. SAR antenna. For an Earth observation SAR, the preferred antenna beam casts an elliptical footprint on the ground with an effective rectangular aperture of typical size 10 meters (along-track) and 3 meters (cross-track). Multi-polarization requires dual polarization antennas with good cross-pol isolation. Practically all SAR antenna designs feature a solid flat aperture (antenna and support structure are a dominant mass and volume factor of a SAR instrument). Digital electronics. The main functions provided by the digital electronics in SAR are: radar configuration and timing control, radar signal digitization and formatting, radar housekeeping telemetry generation. Sometimes digital processing is performed to reduce the data, and the often coded radar illumination pulse is generated digitally.

Imaging radars (SAR instruments) operate at a specific wavelength or frequency in the microwave region. [This is different from optical instruments which observe radiation in a spectral band (a region of frequencies) or in many spectral bands]. A radar system records the signal response from the ground target at a single specific wavelength (e.g. 15 em). Background: The microwave region of the electromagnetic spectrum is generally considered from 1 mm to 1m wavelengths. In analogy to the optical band designations (red, green blue), the microwave spectrum was also given band designations in form of letter references. The military introduced these letter designations in the early days of radar research (mostly for reasons of security during World War II). The remote sensing community seems to adhere to these old "standards" as a means of "ball park reference" designation. Hence, the microwave region includes today such band designations as P, L, S, C, X, K, Ka, etc., for radar (SAR) instruments. Naturally, the rule of specific wavelength (for frequency) operation of a SAR instrument is not affected by this scheme of letter band designations. Newer SAR instruments operating at multiple frequencies are actually an agglomeration of single-frequency instruments.

2077) Note: As coherent pulses transmitted from the radar source reflect from the ground (target) to the advancing SAR instrument (on an aircraft or a spacecraft), the target acts as though in apparent (relative) motion. This motion results in changing frequencies which give rise to variations in phase and amplitude in the returned signals.- Offline processing of these data involves the analysis of the moderated pulses.


IFSAR (Interferometric SAR)- see Interferometric measurements

• SLAR (Side-Looking Airborne Radar)- an active sensor with RAR technology.

• Radar altimeter. An active device observing the vertical distance between the instrument and the ground by measuring the elapsed time between the emitted and returned signals of electromagnetic pulses. Determination (mapping) of the height profile of the surface (topographic applications, in particular of ocean height surfaces).

• Scatterometer. A scatterometer is a nonimaging radar, distinguished from other radars by its ability to measure radiation amplitude. A radar scatterometer is an active device measuring the backscattering coefficient of the illuminated cell (area or volume under observation) at a specified configuration of incidence angles, wavelengths, and wave polarization orientations. The backscattering (or scattering) coefficient o0 describes the target backscattering characteristics (it is defined as the intensity of the power scattered by a 1 m2 area of a target back toward the radar, relative to the incident power density) and varies as a function of surface roughness, moisture content, and dielectric properties. A rough ocean surface returns a weak pulse because sea surface waves scatter the energy of the microwave pulse in different directions. The scattering reduces the amount of energy which is received back at the satellite. On the other hand, a smooth ocean surface returns a strong pulse because there is very little wave effect. The surface roughness is related to the wind speed. High wind speeds disturb the smooth ocean surface and produce many waves of several em in size while low wind speeds do not disturb the ocean surface as much and produce much smaller waves. In addition to windspeed, scatterometers (and SARs) measure the direction that waves are moving in relation to the satellite. The direction that the waves are oriented with respect to the radar pulse has an effect on the polarization of the returned signal. -Application: the surface backscattering coefficient may be used to derive the surface wind vector (in particular over oceans). See also sigma naught.

Lidar (Light Detection and Ranging), see 0.8.5. A lidar instrument is also referred to as an 'optical radar' [or a 'laser radar' - it also goes by the name of 'ladar' (laser detection and ranging)] since it utilizes the optical (and TIR) portion of the electromagnetic spectrum (0.3 - 10 ~m wavelength range, or a frequency range of about 1000 - 30 THz ). A very narrow beam (pulse) of laser light is emitted, the echo is analyzed. Lidar beam divergence is two to three orders of magnitude smaller compared to conventional5 to 10 em wavelength radars. This characteristic permits unambiguous velocity measurements near clouds and surface features.

Radar polarimeter.2078) This radar instrument type measures the complex (amplitude and phase) scattering matrix (i.e. the full polarization signature: VV, HH, VH and HV for transmit and receive signals) for every resolution element in an image. Radar polarimetry is therefore an extension of scatterometry, in which the received power of an echo is typically measured for one or more fixed polarization states and a single, or two orthogonal, transmit states. - Knowing the full scattering matrix permits calculation of the receive power for any possible combination of transmit and receive antennas; this process is called polarization synthesis. Hence, the information content derived from a polarimetric radar instrument is far superior to the information yielded by nonpolarimetric devices. Typical airborne polarimetric radar instruments are: ARMAR, CASSAR, C/X-SAR, DO-SAR, EMISAR, HUTSCAT, MMW-SAR, NUSCAT, P-3/SAR, IMARC, RAMSES, PHARUS, etc. (see Table 8); a typical spaceborne polarimetric radar instrument is the L/C- Band SAR (JPL) of the SIR-C payload. -Note: Conventional imaging radars operate with a single, fixed-polarization antenna for both transmission and reception of radio frequency signals. In this way a single scat-

2078) H. A. Zebker, J. J. van Zyl, "Imaging Radar Polarimetry: A Review," Proceedings of the IEEE, Vol. 79, Nr. 11, November 1991, pp. 1583·1606


tering coefficient is measured for a specific transmit and receive polarization combination for many thousands of points in a scene. A result is that only one component of the scattered wave, itself a vector quantity, is measured, resulting in a scalar characterization of the wave, and any additional information about the surface or volume contained in the polarization properties of the reflected signal is lost.

Radar albedo. Ratio of a target's radar cross-section in a specified polarization to its projected area; hence, a measure of the target's reflectivity.

Radar backscatter. Refers to the radar echo; a scattering process of microwave energy by an object/target in the direction of the radar antenna, after actively being irradiated by the radar source.

Radar cross section. A hypothetical area of an object of such an extent that if the power intercepted by this area were distributed isotropically over the space, it would render the same power density at the receiving antenna as the power density brought about in reality by the presence of the object or target. Usually, the radar cross-section concerning compound objects (distributed targets) is normalized: either as a radar cross section per unit area ( differential scattering cross section or backscatter coefficient a"), or as a radar cross section per unit of area projected in the direction of transmission (gamma or scattering cross section). 2079)

Radar meteorology. A discipline that uses backscattered electromagnetic radiation within the microwave band to gain information about the state of the atmosphere, especially with respect to clouds and precipitation. The return signal allows the interpretation of four fundamental properties of the spectrum: amplitude, phase, frequency, and polarization.

Radian. The size of angles in classical mechanics is expressed in radians. The concept of radians permits a simple mathematical relationship between the length L of the arc of a circle (i.e. a segment of the circumference) and the angle subtended (enclosed) at the axis by the arc. The arc length Lis given by: L=R 8. This means that when the length of the arc is equal to the radius (L= R ), then 8 is one radian (or the angle at the center of the circle subtended by an arc equal to the radius is one radian). In one revolution the arc length is equal to the circumference, so that L=2nR, or 8=2n radians, or 1 radian = 2n/360° =57.28°. Example: for R=lOOO m and 8=0.2 radians (FOV), then L=200 m (in case of a sensor, the swath width).

Angular size with no distance information is usually the only information available in observational astronomy. Some sample angular sizes are:

The full moon subtends 30 arcminutes The Andromeda galaxy subtends about five degrees

Radiance. Energy per unit area and solid angle. Measure of energy radiated by an object. In general, radiance is a function of viewing angle and spectral wavelength.

Radiation laws.

Planck's law (Max Planck, 1858-1947). Eb/. = 2 h c2 J,.-5 I [e(hc/AkT) -1], where EbJ. = monochromatic emissive power (or spectral radiance, or brightness) per unit wavelength interval, A= wavelength, T=absolute temperature, h = Planck's constant, k = Boltzmann's constant, and c = speed of light. In words, Planck's law states that the temperature of a blackbody is related to the

2079)H. J. Buiten, J. Clevers, "Land Observation By Remote Sensing," Gordon and Breach Science Publishers, ISBN 2-88124-936-6, 1993, p. 608


emitted radiance as a function of the wavelength (or of the frequency). Planck's equation is plotted in Figure 422 for several temperatures.

Note: The term 'spectral radiance' is commonly used for remote sensing instruments operating at optical wavelengths, while the term 'brightness' is mainly used for the microwave region of the spectrum. Then Planck's law is expressed in units of power density per frequency bandwidth (Hz-1) rather than per unit wavelength interval ( m·1 ). Spectral brightness Bf is related to spectral radiance Eb).. by: Bf = Eb).. I dA!df I, which results in: Bf = 2 h f3 c·2; [ e(hf/kT) - 1 ].

In the microwave region (f < 300 GHz), the term hf/kT « 1 for the range of physical temperatures commonly encountered in the Earth's surface and atmosphere. Consequently, the spectral brightness equation above reduces to a simpler form: Bt=2kT/I..Z which is known as the Rayleigh-Jeans law, a special case of Planck's blackbody radiation law (see also brightness temperature).

105 FIR

104

103

102

8 <=I 10 "' :0 "' ~ -;;; t (I) 10·1 0.. [/)

(I)

·Ei 10·2 "' ~

10-3

w-4

w-s

10-6 0.1 0.2 0.5 2 5 10 20 50 100

Wavelength (!!m)

Figure 422: Hemispherical radiation emitted by objects at typical temperatures

• Wien's displacement law (Wilhelm Wien, 1864-1928). A law indicating that the wavelength at which the emitted amount of energy by a blackbody is maximal is inversely proportional to the absolute temperature of that body.

• Kirchhofrs law (Gustav Robert Kirchhoff, 1824-1887). Alaw stating that under conditions of thermal equilibrium, the absorption spectrum cif an arbitrary body must be equal to its emission spectrum. Kirchhoff's identity: e (emissivity)=a (absorptivity).

• Lambert's law (Johann Heinrich Lambert, 1728-1777). A law stating that the radiant intensity (flux per unit solid angle) emitted in any direction from a unit radiating sur-


face varies as the cosine of the angle between the normal to the surface and the direction of radiation. The radiance of a radiating surface is therefore independent of direction. This law is also satisfied (by definition) by the distribution of radiation from a perfectly diffuse radiator.

Radiation hardening. Exposed satellite and instrument components, such as detectors, are constantly subjected to space irradiation effects. In particular, long-term exposure may cause radiation damage to electronic components by altering the properties of a material arising from exposure to ionizing radiation (penetrating radiation), such as X -rays, gamma rays. neutrons, or heavy-particle radiation. With proper hardening processes applied, the components may be turned into radiation-tolerant products.

Radio beacon. A type of radio transmitter with wide-angle coverage. It may emit signals continuously or, like the transponder, may respond to input energy before operating. Beacons are use primarily in navigation and radio-detection finding. In meteorology a beacon is used in rawinsonde observations.

Radiodetermination. Refers to the determination of position, velocity and/or other characteristics of an object, or to obtaining information relating to these parameters, by means of the propagation properties of radio waves. The radiodetermination service has two parts to it: the radionavigation service and the radiolocation service (see also Figure 412).

1) Radionavigation Systems. Radionavigation is used for the purpose of navigation (aero-nautical, maritime, land, and space), including obstruction warning.

LORAN-e (Long Range Navigation) operates on 100kHz; it is used in maritime and aeronautical applications (see LORAN) Omega is a worldwide ew system; it is used for maritime and aeronautical navigation. System operation in the VLF band (9-14kHz) on four discrete frequencies. (see OMEGA) VOR/DME (VHF Omnidirectional Range/Distance Measuring Equipment). VOR operates in the 108-118 MHz band, providing azimuth readings to aircraft. DME is collocated with VOR providing distance; it operates in the 960-1215 MHz band. TAeAN (Tactical Air Navigation) is the US military version ofDME.It operates in the 960-1215 MHz band. ILS (Instrument Landing System) for precision navigation. ILS consists of a localizer operating in the 108-112 MHz band and a glidescope operating in the 328.6-335.4 MHz band. MLS (Microwave Landing System), operating in the 5000-5150 MHz range with associated DME in the 960-1215 MHz range. MLS was initially considered a successor to ILS. It probably may be succeeded by GPS systems. GPS (Global Positioning System), a US satellite-based system operating in the 1215-1240 MHz and 1559-1610 MHz bands. GPS was officially integrated into the US National Airspace System on February 17, 1994. In the future, GPS is expected to replace such systems as Omega, LORAN-e, and perhaps VOR/DME. GLONASS (Global Orbiting and Navigation Satellite System), a Russian satellitebased system operating in the 1215-1260 and 1559-1626.5 MHz bands. By the year 2005 the second bandwidth of GLONASS is expected to be the same as that of GPS. There is a major trend towards increased use ofthe GPS and GLONASS satellite-based system for many navigation applications. etc.

2) Radio location Systems: The service is used by pulsed and ew radar systems for anumber of applications, such as determining precise location, search or surveillance, target tracking, weapons control, ground mapping and target identification, or combinations


of these applications. The military is by far the largest user of this service, but there are also a number civil users (NASA, NOAA, CNES, CRC, Russia, etc.2080)

S&RSAT (Search & Rescue Satellite, CNES/CRC) flown on NOAA-POES satellites. The S&R instruments consist of a 3-band (121.5, 243, and 406.05 MHz) repeater S&RR and a 406.025 MHz processor. The system may receive three types of radio beacons, namely aviation ELTs (Emergency Locator Transmitter), maritime EPIRBs (Emergency Position Indicating Radio Beacon), and PLBs (Personal Locator Beacon). S&RSAT was declared operational in 1985. The COSPAS-SARSAT agreement was signed in 1988.2081) CO SPAS (Space System for Search of Vessels in Distress, Russian system). The system is flown on Cospas series satellites (named Nadezda) and administered by Russia, US, France, and Canada. Distress alert and location data to RCCs (Rescue Coordination Centers) for 121.5 MHz beacons within the area of COSPAS-S&RSAT ground stations (Local User Terminals- LUTs), and for 406 MHz beacons activated anywhere in the world. IVHS (Intelligent Vehicle Highway Systems) or ITS (Intelligent Transport Systems) etc. i082)

Radiometer. An instrument for the quantitative measurement of the intensity of electromagnetic radiation in some band of wavelengths in the spectrum. Usually a radiometer is characterized with a prefix, such as IR-radiometer, or microwave-radiometer, to indicate the spectrum to be measured.

Radiometer (absolute radiometer). An instrument based on the measurement of a heat flux by an electrically calibrated transducer. Optical radiation absorbed in a black cavity is substituted by electrical heating during a shaded reference phase. For practical use of the instrument, an electronic circuit keeps the heat flux constant by controlling the power fed to a cavity heater (this is also referred to as substitution radiometry- directly relating the optical watt to the electrical watt). Absolute radiometers are used to measure the Solar Constant or TSI (Total Solar lrradiance ).

Note: electrical substitution radiometry at cryogenic temperatures is also the basis of detector calibrations in which a detector's response to optical flux is measured as a function of wavelength.

Radiometric resolution. See resolution.

Radiosonde. A balloon-borne instrument which measures (by means of transducers) and transmits meteorological data (temperature, pressure, humidity). Various types of transmission schemes exist.

Rawinsonde (Radio-Wind-Sonde). A balloon-borne instrument tracked by radar or radio direction-finder and operating on the same principle as a radiosonde, but with the additional capability to measure wind speed and direction. Dropsonde. A radiosonde or a rawinsonde dropped by parachute from an aircraft for the purpose of obtaining soundings of the atmosphere below. The radio signals of the dropsonde/rawinsonde are tracked for data evaluation.

Radio occultation principle. Fundamentally, the technique relies on the simple fact that a planet's atmosphere acts much like a spherical lens, bending and slowing propagation of microwave signals passing through it tangent to the surface. The lens effect results from decreasing atmospheric density with altitude. If the positions of transmitting and receiving satellites are precisely known, then the atmospheric delay can be measured precisely, the

2080) US Spectrum Requirements, URL: http://www.ntia.doc.gov/openness/sp_rqmnts/radar4.html 2081) NOAA S&RSAT homepage, http://psbsgil.nesdis.noaa.gov:8080/SARSAT/homepage.html 2082) COSPAS-S&RSAT homepage, http://www.worldserver.pipex.com/cospas-sarsat/


time derivative of which (Doppler) can be inverted to give atmospheric density versus altitude. See also Limb/Occultation sounding and Occultation. -Note: The radio occultation technique was first developed (in the 1970s) at Stanford University Center for Radar Astronomy and at NASNJPL for the study of solar system planetary atmospheres (Venus, Mars, Jupiter, Saturn, Uranus and Neptune).

Raman spectroscopy. 2083) A technique to investigate molecular properties using scattered light resulting from photon-molecule collisions. When a monochromatic light beam is incident on systems such as transparent gases, liquids, or solids, most of it is transmitted without change. However, a very small portion of the incident light is scattered. Although most of the scattered light has the same wavelength as the incident radiation, a small part of it has different wavelengths. The scattering oflight at different wavelengths is called Raman scattering (Indian scientist Sir C. V. Raman, who, with K. S. Krishnan, first reported the phenomenon in 1928). The physical origin of Raman scattering lies in inelastic collisions between the molecules composing the system (e.g. the liquid) and photons, the particles composing the light beam. 'Inelastic collision' means that there is an exchange of energy between the photon molecule with a consequent change in energy, and hence wavelength, of the photon.

Range. The distance between two objects, usually between an observation point and a target (object under observation). Slant range: same as range- the line-of-sight distance between two objects.

Range direction. Observation of an instrument in the cross-track direction (normal to the subsatellite track). See also azimuth direction.

Range error. The (small) error in radar range measurement caused by the propagation of radio energy through a nonhomogeneous atmosphere. This error is due to the fact that the velocity of radio-wave propagation varies with the index of refraction, and that ray travel is not in straight lines through actual atmospheres (see also Atmospheric refraction).

Range resolution. Resolution characteristic of the range dimension, usually applied to the image domain, either in the slant range plane or in the ground range plane. Range resolution is fundamentally defined by the system bandwidth in the range channel. See also SAR.

Raster image. Refers to a matrix of row and column data points. Each data point is a pixel.

Rayleigh criterion. It states that the resolution of a system is directly proportional to the wavelength. Thus, with perfect optics, an imaging system working at 50 nm (EUV wavelengths) would have an order of magnitude better resolution than one working with visible light (about 500 nm wavelength).

Rayleigh scattering. Scattering by particles small in size compared with the wavelengths being scattered (e.g., the blue color of the sky and ocean is caused by Rayleigh scattering of the air and water molecules respectively). Rayleigh scattering is also caused by density fluctuations in atmospheric gases (it increases toward the shorter wavelengths proportional to A.-4

where A. is the wavelength). In a sensor energy balance, Rayleigh scattering adds to the radiation received by a sensor; this is most pronounced at shorter wavelengths.

Reaction/momentum wheels. These are actuators (fly wheels) which may be used for threeaxis reaction control or momentum bias applications. By adding or removing energy from the flywheel, torque is applied to a single axis of the S/C, causing it to rotate (reaction). By maintaining flywheel rotation (momentum), a single axis of the spacecraft is stabilized. Such an assembly provides a reliable source of reaction torque and angular momentum storage for attitude control of medium to large spacecraft. Accelerating or decelerating a flywheel with an integral motor provides a means of controlled momentum exchange with the spacecraft platforms, which is advantageous for a variety of attitude control schemes.

2083) Encyclopedia of Physical Science and Technology, Academic Press, 1987


Real-Time Kinematic (RTK). Refers to a DGPS process where carrier-phase corrections are transmitted in real-time from a reference receiver at a known location to one or more remote "rover" receivers. RTK has become a preferred method for surveying applications since it provides real-time positions with high accuracy.

Reflectance. Refers to the fraction of the total radiant flux incident upon a surface that is reflected and varies according to the wavelength distribution of the incident radiation.

Reflection. The scattering of electromagnetic radiation by an object. Diffuse reflection causes the radiance of the reflected radiation to be equal in all directions (e.g. reflection from a rough surface). Specular reflection has a direction of preference (e.g. the reflection of a smooth surface). The use of the terms 'smooth' and 'rough' is independent of wavelength.

Reflectivity. A property of illuminated objects to reradiate a portion of the incident energy. For SARs, backscatter is the observable portion of the energy reflected. Backscatter, in general, is increased by greater surface roughness.

Refraction. A process by which the direction of energy propagation is changed due to a change in density within the propagating medium (smooth bending), or due to a discontinuity between two media (abrupt bending). - Atmospheric optical phenomena are produced by continuous and discontinuous refraction: scintillation, mirages, astronomical refraction, anomalous propagation of radio waves and the bending of sound waves are examples of refraction within a single medium.

Refractive index (in a medium). The inverse ratio of the wavelength (or velocity) of electromagnetic radiation in the medium to that in vacuum. A measure of the amount of refraction (a property of the dielectric constant). See also Atmospheric refraction and Occultation.

Registration. Geometric rearrangement of the pixels in an image for image matching by superposition - often to the reference geometry of a map (geocoding). Image registration is the process of matching (overlaying) two or more images so that corresponding coordinate points in the images correspond to the same physical region of the scene being imaged. The technique is used for a number of applications:2084l

• Integration of information taken from different sensors (sensor or image fusion) Analysis of changes in images taken at different times (temporal registration and change detection).

In a wider sense image registration tries to combine image data with different spatial, spectral and radiometric characteristics to improve the information extraction process from available imagery. Typical registration processing steps are: feature identification, feature matching, spatial transformation, and interpolation.

Relative aperture. For a photographic or telescopic lens system, the ratio of the equivalent focal length to the diameter of the entrance slit. It is expressed as f/45 or f/5.6, and is also called the 'f-number,' speed of lens, or the 'focal ratio.'

Renewable energy. Refers to energy technologies that generate electricity, fuels, and/or heat through the use of resources which are continually replenished, such as sunlight (photovoltaic), heat from the sun (solar thermal), wind, naturally occurring underground steam and heat (geothermal), plant and animal waste (biomass), and water (hydropower).

Repeat period (or cycle). Time interval between successive satellite observations of the same area of the Earth's surface.

Resampling. The rearrangement of the resolution cells of each scanned line of an image into geometrically equal terrain elements (geometric rearrangement) by creating artificial

2084) L. M. G. Fonseca, B. S. Manjunath, "Registration Techniques for Multisensor Remotely Sensed Imagery," PE&RS, Vol. LXII, No.9, Sept. 1996, pp. 1049-1056


pixels whose spectral radiation data are computed from the original values proportional to the area coverage by the new pixels with respect to the resolution cells. In general a resampling process follows after a geometric rearrangement (registration) of the pixels because of the matching of two different images of the same region by means of a mathematical transformation. The resampling then involves the assignment of artificial pixel values to the newly formed pixels according to the selected sampling algorithm.

Resolution. A term defining the smallest discernable physical unit of an observed signal by a sensor.

Spatial or geometric resolution defines the minimum (spatial) separation between two measurements in order for a sensor to be able to discriminate between them. Spatial resolution defines the size of an image resolution cell in the target area, or the size of pixels. The spatial resolving power is determined by the aperture dimensions of a lens or the antenna of a sensor. - Some spatial connotations are: GSD, IFOV, FOV, look angle of the sensor, shape and size of the object, position, site, distribution, texture. Spectral resolution refers to the resolving power of a system in terms of wavelength (or wavenumber) or frequency. Radiometric resolution refers to the resolving power of a system in terms of the signal energy [detection of energy differences (reflection and emission) in terms of temperature, intensity and power]. The radiometric resolution is the Noise Equivalent Delta Radiance (NE~R), or the Noise Equivalent Delta Temperature (NE~T), depending on the spectral measurement range. This can be defined as the minimum change in reflectance (or temperature) that can be detected by a sensor. The value depends on a number of parameters, such as SNR, the saturation radiance setting, and the number of quantization bits. The important parameter of an instrument is the SNR. The resolution capability of an instrument in terms of quantization does not necessarily give an idea of its precision or accuracy with which it can measure. Nevertheless, a higher number of bits increases the dynamic range of the instrument, permitting the measurement of very variable targets, without a gain change. See also Full Width Half Maximum. Temporal resolution concerns the time lapse between two successive images of the same area (by the same spaceborne sensor, at the next revisit time).

Rheology. A science dealing with the deformation and flow of matter.

S/A (Signal-to-Ambiguity ratio). In SAR instruments the ratio of the receiving power of the signal scattered and reflected from the observed (target) area to the power leaking into the observation area from the non-observed area.

SAR (Synthetic Aperture Radar), see SAR under Radar.

Satellite surface charging. All bodies which are placed in a plasma in thermal equilibrium acquire a negative electrostatic charge. The negative potential depends on the plasma temperature. At altitudes of 300 to 500 km, the average kinetic energy of the plasma is low ( < 1 e V), hence, satellites become only weakly charged. At high altitudes (geostationary orbit and further out) the kinetic energy of the plasma is considerably larger (the plasma is referred to as 'hot'), hence, satellites acquire a high potential with respect to it (in the order of several ke V). The electrostatic charge on satellite surfaces can pose a hazard, in particular when differential charging is leading to potential gradients. In some cases this potential build-up causes discharge arcing. Electrostatic charging by the natural space radiation environment is an accepted source of many anomalies of SIC electronics.

Satellite classes. Satellites may be categorized by a number of different criteria such as mass (large, small, mini, micro), or functions and services (EO, communication, space science, data collection, navigation, orbit, etc.), or by other criteria. Within the last years advances in digital microelectronics resulted in achieving sophisticated functions within ever smaller constraints of mass, volume, and power. This in tum brought about a miniaturization trend in platforms and instruments, and a demand for low-cost projects. The following classification has become widely accepted:


Satellite Class Mass Large satellite (obseiVatory, etc.) > 1000 kg Medium size satellite 500- 1000 kg Minisatellite Small Satellite Class 100-500 kg Microsatellite (or LightSats) 10- 100 kg Nanosatellite 1 -10 kg Picosatellite < 1 kg

Table 562: Satellite classification by mass criterion

Satellite Laser Ranging (SLR). Very precise range measurements from ground reference stations to geodynamic satellites (like Lageos, Starlette, Stella, Geo-IK, Etalon, EGS, etc.). The SLR technique employs short pulse lasers from the ground to retroreflectors on satellites. While the above listed geodynamic satellites are dense reflector-covered spheres (dedicated to laser ranging), there may also be configurations where a satellite flies a retroreflector arrangement as an experiment. The quantity of interest is time-of-light (round trip) corrected for ranging system internal delay (calibration), atmospheric refraction (delay), retroreflector offset to the S/C center-of-mass, and network epoch synchronization. The short wavelengths of visible light result in a single-shot precision of about 2 em. SLR techniques are a strong contributor to advances in precision orbit determination. The applications of SLR data from geodetic satellites includes detection and monitoring of tectonic plate motion, crustal deformation, earth rotation, and polar motion; modeling of the spatial and temporal variations of the earth's gravitation field; determination of basinscale ocean tides; monitoring of millimeter-level variations in the location of the center of mass of the total earth system (solid earth-atmosphere-oceans); establishment and maintenance of the International Terrestrial Reference System (ITRS); detection and monitoring of post -glacial rebound and subsidence; monitoring the response ofthe atmosphere to seasonal variations in solar heating.

Satellite structure: Basic Elements. Satellite structures must survive launch, meet outgassing and other mission-specific requirements, provide stiffness, dimensional stability and thermal control, and allow equipment mounting and containment. Remote sensing satellites are comprised of a number of subsystems. The actual number of subsystems depends on the complexity of the mission and the overall design of the spacecraft. The trend is in the direction of standardized modular subsystems with high functional autonomy. • Satellite structure. Refers to the basic platform or "bus" (design, body, shape, etc.) and

subsystem accommodation. • Thermal control subsystem (passive and/or active). Orbital temperatures may vary

considerably due to varying solar irradiation. The subsystem provides the proper thermal environment for a number of subsystems (in particular electronic or optical equipment). Thermal balance may be maintained by using an exterior finish that absorbs or emits radiation; this is referred to as a 'passive system.' An active system may use louvers to achieve a required environment G&C (Guidance and Control) subsystem. G&C is responsible for all functionality associated with spacecraft attitude (sensing and control), a basis for proper SIC pointing. G&C is sometimes simply referred to as 'attitude control.' See also Spacecraft stabilization. Power subsystem. The subsystem is responsible for providing continuous power for all subsystems throughout the mission. The two most common power sources are solar cells and high performance batteries. The solar energy may vary depending on satellite orbit (due to sun eclipses or varying sun elevation angles). Batteries (such as NiCd or NiH2) are used as a supplemental on-board energy source. Power distribution. Refers to the spacecraft cabling system to all subsystems. Sometimes this electrical distribution function is integrated into the spacecraft bus. Antenna subsystem. The subsystem is responsible for receiving and transmitting telecommunication signals between ground and spacecraft (maybe in several bands).


C&DH (Command and Data Handling) subsystem. The subsystem is responsible for command processing, data management, health and status management, telecommunications management, and power management. Spacecraft bus. A shared communications medium for all subsystems (like serial busses or parallel backplane busses). This requires a common interface definition. Some SIC series of agencies or companies offer standardized systems capable of accommodating a variety of payloads and subsystems. Newer designs consider the SIC bus as the physical structure for distribution of all on-board services (data, electricity, etc.) to the payload along with the integration of all service subsystems (attitude and control, timing, thermal control, etc.). Spacecraft computer. Depending on spacecraft complexity there may be a S/C com puter and/or subsystem computers. Data recorder. Responsible for recording data streams during non-contact periods of the SIC. This may be an independent device (high volume and high data rate) or solid state memory storage in a S/C computer. Payload instruments. A suite of sensors performing assigned observations. Such instruments may be imagers, sounders, radiometers, etc. Timing subsystem. Responsible for giving a uniform time stamp to all required interfaces.

• GPS receiver. Ever more satellites are carrying such a system for orbit determination.

Scales (macro-, meso-, and micro scales). See observational scales in modeling chapter 0.13 on page 1278.

Scanning. The sweep of a mirror, prism, antenna, or other element across a track (normal to the direction of flight); the footprint may be a straight line, a circle or any other shape. In general, the process of scanning is a programmed motion that can be used either for measuring angular location of a target, or it can be used to extend the angular range of an antenna beam. There are two basic ways of classifying scanning methods:

From the viewpoint of the type of beam motion introduced to scan a volume, the methods are described as: raster scan, helical scan, etc. From the viewpoint of beam steering, the methods are described as mechanical, electromechanical, or as electronic.

Scanner. An instrument that scans and by this means produces an image. A two-dimensional image is generated by the forward motion of the satellite platform. The addition of single pixels in combination with cross-track scanning (whiskbroom) or of a cross-track line of pixels (CCD line array) are the basic elements of such an image. Common scanner types are: a) whiskbroom (cross-track multispectral imaging with discrete detectors), b) pushbroom (cross-track multispectral scanner with CCD line arrays), c) hyperspectral scanning with area arrays (see chapter 0.3).

ScanSAR. A SAR imaging technique permitting acquisition of a larger observation swath than what would normally be possible due to range-Doppler ambiguity limitations, but at the expense of reduced resolution. The technique, based on phased array antenna technology with a rapid electronic steering capability of the elevation beam pattern, permits a high degree of flexibility in ground observation coverage. The principle of this mode of operation is to illuminate an area on the ground long enough to acquire imagery (synthetic aperture) for the desired resolution and then move the illuminated beam to a different area across the swath to increase coverage. Hence, the operational time of the SAR beam pattern is shared between two or more subswaths in such a way as to obtain full image coverage of each. However, a contiguous subswath coverage implies shorter integration times for each footprint, resulting in shorter integration times - consequently, the resolution of the resulting image is degraded. The ScanSAR technique may also serve to cover an event of interest, positioned close-by


but still outside the normal coverage of the current orbit. The required beam pointing for such an event can be done on command.

Scattering. Light absorbed and subsequently re-emitted by particles suspended in a medium in all directions at about the same frequency. In scattering no energy transformation results, there is only a change in the spatial distribution of the radiation. - Scattering varies as a function of the ratio of the particle diameter to the wavelength of the radiation. When this ratio is less than about one-tenth, Rayleigh scattering occurs in which the scattering coefficient varies inversely as the fourth power of the wavelength. At larger values of the ratio of particle diameter to wavelength, scattering varies in a complex fashion described by the Mie theory (particle size is comparable with the wavelength dimension). At a ratio of the order of ten, the laws of geometric optics begin to apply and this serves to mark the somewhat diffuse upper boundary of the realm of scattering (where diffraction begins). Primary scattering of the Rayleigh type, largely by air molecules, is responsible for the blue sky and the polarization of the sky's light. On the other hand, Mie scattering occurs by the interaction of radiation (light) with aerosols or cloud particles.

Scattering matrix. An array of complex numbers that describes the transformation of the polarization of a wave incident upon a reflective medium to the polarization of the backscattered wave. See also radar polarimeter under radar.

Scatterometer types. There are two basic designs of scatterometers: the traditional fanbeam Doppler scatterometer (examples: NSCAT, AMI-SCAT), and the scanning pencilbeam scatterometer. The fan-beam Doppler scatterometer requires multiple antennas to achieve the target illumination pattern (sticklike antennas are used to broadcast long, narrow radar footprints). The FOV requirements of the antennas are very strict making fanbeam scatterometers very difficult to accommodate on SIC.- The design of the newer scanning pencil-beam instrument is more compact; they offer long dwell times which result in better SNRs. Sea Winds on ADEOS-11 will be a scanning pencil-beam scatterometer.2085)

Schottky diode (named after Walter H. Schottky). A diode that has a metal-semiconductor contact (e.g., an Allayer in intimate contact with ann-type silicon substrate). The Schottky diode is electrically similar to a p-njunction, though the current flow in the diode is due primarily to carriers having an inherently fast response. It is used for high-frequency, low-noise mixer and switching circuits.

Scintillation. Variations in the brightness of starlight (i.e. 'twinkling') caused by turbulent strata very high in the Earth's atmosphere (ionosphere). Also, the emission of sparks or flashes. In general, scintillation refers to the fluctuation of amplitude and/or phase of a signal caused by the irregular structure of the propagating medium.

Scintillation counter. A device that uses a photomultiplier tube to detect or count charged particles (which produce scintillations of radiation when they impact upon phosphor) or y-rays.

Sea Surface Salinity (SSS). SSS is an important variable in oceanography. In polar oceans, SSS intrusions with a low salinity influence the deep thermohaline circulation and the meridional heat transport. Variations in salinity also influence the oceans near surface dynamics in the tropics where rainfall modifies the buoyancy of the surface layer and the tropical ocean-atmosphere heat fluxes (warm surface pool dynamics). 2086)- The physical basis for SSS remote sensing is the microwave brightness temperature (low frequency range in Lband around 1.4 GHz) which is directly linked to the dielectric constant of the target area (i.e., moisture or salinity); hence, proportional to moisture or salinity. SSS retrieval requires

2085)D. G. Long, M. W. Spencer, "Radar Backscatter Measurement Accuracy for a Spaceborne Pencil-Beam Wind Scatterometer with Transmit Modulation," IEEE Transaction on Geoscience and Remote Sensing, Vol. 35, No. 1, Jan. 1997, pp. 102-114

2086) G. Lagerloef, C. Swift, D. LeVine, "Sea Surface Salinity: The next remote sensing challenge," Oceanography, 8, 1995, pp. 44-50


knowledge of sea surface temperature and sea roughness and, additionally, it also requires a very high sensitivity from the sensor. 2087)

Semiconductor junctions. Semiconductors whose principal charge carriers are electrons are called n-type (negative ).If the charge carriers are mainly holes (a vacancy with positive charge), the material is p-type (positive).

Sensor. An instrument (generic term), usually consisting of optics, detectors, and electronics that collects radiation and converts it to some other form. The form may be a certain pattern (an image, a profile, etc.), a warning, a control signal, or some other signal. - The photographic camera is one of the best known examples of a 'remote sensor' which has been around since the first half of the nineteenth century.

Sensor characteristics. The ability of a sensor to detect and to resolve incoming radiation. For imaging sensors a very prominent characteristic is 'ground resolution,' its ability to distinguish objects on the Earth's surface. Other sensor characteristics are: scene size, spectral range, spectral resolution, radiometric resolution, pointing accuracy (location knowledge), and timeliness (in which images are returned to the user, the frequency at with which a given target can be revisited, the fraction of time that the sensor requires for taking an image).

Shielding. Refers to a technique of enclosing an object or a device within a container specifically designed to attenuate or otherwise exclude electromagnetic radiation.

Sidelobes. See antenna sidelobes.

Sigma ( o). The conventional measure of the strength of a radar signal reflected from a geometric object (the target area). Sigma designates the strength of reflection in terms of the geometric cross section of a conducting sphere that would give rise to the same level of reflectivity. See also radar cross section.

Sigma naught (u0 ). Scattering coefficient, the conventional measure of the strength of radar signals reflected by a distributed scatterer, usually expressed in dB. It is a normalized dimensionless number, comparing the strength observed to that expected from an area of one m2. Sigma naught is defined with respect to the nominally horizontal plane, and in general has a significant variation with incidence angle, wavelength, polarization, as well as with the properties of the scattering surface itself.

Signal-To-Noise Ratio (SNR). The ratio ofthe level of information-bearing signal power to the level of noise power. The maximum SNR of a device is called the 'dynamic range.' In general, the higher the value of an instrument's SNR, the better the signal quality for recognition (detection) and interpretation.

Signature. The response of electromagnetic radiation to particular objects in the target area. Signatures may be used for pattern recognition which may in turn lead to target identification.

• The radar signature is the radar response (differential radar cross-section or the scattering cross section) of a particular material or object as a function of frequency, angle, polarization, or time. The spectral signature is the radiation response of an object as a function of wavelength.

Solar absorption technique. A method for measuring atmospheric constituents. As sunlight passes through the Earth's atmosphere, certain wavelengths are selectively absorbed by gaseous constituents. In the infrared region, nearly all gases have characteristic, discrete absorptions, whose positions and relative strengths are known from laboratory measurements of pure gas samples. This permits gaseous atmospheric constituents between the sun and an observer to be identified and quantified from high resolution solar spectra.

2087) http://www-sv.cict.fr/cesbio/smos/


Solar cell. An optoelectronic device (invented in 1954) that converts the radiant energy of sunlight directly into electrical power, based on photovoltaic principles. The solar cell is a large-area photodiode that detects the solar emission spectrum rather than a specific wavelength, as do photodiodes. The solar cell is unbiased, the load is connected directly across the two terminals of the p-n junction. Conversion efficiency, radiation hardness, and EOL (End Of Life) power are very important properties of solar cells. They are usually arranged in arrays or panels for spacecraft powering. During the 40 years of space technology, three generations of solar cells have been introduced:

• Silicon (Si) solar cells dominated the field until the early 1990s Gallium arsenide (GaAs) solar cells arrived in about 1990. They have better conversion efficiencies and radiation resistance in comparison with Si cells. GaAS cells can be manufactured on lightweight germanium substrates. The third generation of solar cells is the multifunction cell, or cascade cell. Current multijunction cells are based on GainP (Gallium Indium Phosphide) material and GaAs on Ge substrate.

Solar cycle. The 9.5 -11 year period between maxima (or minima) of solar activity (usually measured by the number of sunspots on the solar surface). About every 11 years the magnetic field of the sun reverses polarity; hence the more basic period may be 22 years. It is generally accepted that the solar cycle is maintained by a dynamo driven by the differential rotation of the sun's envelope.

Solar sail. A low-thrust propulsion technology (in the experimental/demonstration phase at the tum ofthe century) whose concept relies on the momentum transfer of photons (solar radiation pressure) on large, highly reflecting sails in space for passive propulsion such as orbit transfer functions. The concept involves the deployment and control (orientation) of a large sail in orbit on lightweight structures. The technology of such solarcraft is of interest for interplanetary missions.

Solar wind. A radial outflow of plasma from the solar corona, carrying mass and angular momentum away from the sun (see chapter 0.18). The solar wind consists of a flux of particles, chiefly protons and electrons together with nuclei of heavier elements in smaller numbers, that are accelerated by the high temperatures of the solar corona, or outer region of the Sun, to velocities large enough to allow them to escape from the sun's gravitational field. At 1 au (astronomical unit) the solar wind contains approximately 1-10 protons/cm3

moving outward from the sun at velocities of 350 to 700 km/s (or about 1.26 -2.52 million km/h); this creates a positive ion flux of 108 to 109 ions/(cm2 s), each ion having an energy equal to at least 15 e V (electron volts). During solar flares, the proton velocity, flux, plasma temperature, and associated turbulence increase substantially.

Sounder. A remote sensing instrument that measures state parameters (like temperature, pressure, moisture, etc.) in a particular plane of observation for the derivation of profiles. A sounder may be a passive device by measuring the incoming radiation, it can also be an active device, transmitting signals (echo sounding) and receiving the echo information. Two basic configurations are in use:

In the nadir-viewing configuration the observation plane is the orbit plane of the platform (series of footprints along the suborbital track). The scan technique provides good horizontal resolution of the measurements, but usually poor vertical resolutions.

Limb sounders look at the horizon (the limb) and scan vertically, producing good vertical resolution but poor horizontal resolution.

Sounding. To 'sound' (to find bottom) originally referred to the measurement of water depths by sounding methods (sounding line, echo sounding, etc.) in shallow coastal waters and in rivers. The technique was much later extended to measure also the conditions of another medium, namely the atmosphere, at various heights. The first devices used were


balloons with self-registering instruments (referred to as sondes) to record meteorological data. As new technologies became available, radiosondes, dropsondes from aircraft, rawinsondes, sounding rockets, ground-based, airborne and spaceborne instruments of a great variety appeared.

Spacecraft/platform attitude sensing and control devices.

1) A S/C attitude or pointing direction is determined by comparing information from various on-board sensors with the positions of known references. Attitude knowledge may be derived from the following orientation instruments:

Magnetometers (measuring the known magnetic field components) Sun and/or star sensors or trackers (measuring of known celestial body directions)

• Earth horizon sensors (various types, mostly in theIR region; a horizon crossing indicator may determine the attitude of a spin-stabilized S/Cwith respect to the Earth; another horizon sensor may measure one component of the attitude of a three-axis stabilized SIC with respect to the Earth; there are scanning IR Earth horizon sensors, etc.). Gyroscopes (measuring inertial reference) GPS receiver (capable of measuring attitude). These GPS attitude instruments provide attitude and attitude rate data to actuators for real-time, autonomous attitude determination. Telescope (instrument guide telescope)

etc.

2) The following instruments (or combinations thereof), referred to as actuators, provide attitude control:

Momentum gyros Reaction/momentum wheels

• Thrusters (cold gas thrusters, solid thrusters, ion thrusters, mono- or hi-propellant engine, etc.) Magnetic torque coil/rods (magnetorquers) Permanent magnets Gravity gradient boom Nutation damper etc.

The simplest attitude control system is passive stabilization, either magnetically (a magnetometer as sensor in combination with a magnetic torque rod as actuator) or by gravity gradient methods. Passive stabilization can also be combined with active components, e.g. gravity gradient systems with magnetic torquers are quite common. Simple spinners, and momentum biased satellites represent the next advanced level of attitude control system, requiring at least for the momentum biased system some active stabilization about the angular momentum axis (typically the pitch axis). Zero-momentum systems with either reaction wheels or thrusters are the most complex systems, they require constant stabilization and become unstable if control is lost only for a short period of time. Simple and passively stable systems have a low pointing performance, and complex systems using reaction wheels are highly accurate pointing systems. 2088)

Spacecraft/platform and instrument pointing. Good location knowledge of a target (of the ground surface, of a celestial body, etc.) by instrument pointing is an ever-present requirement of many missions (in particular for astronomy instrument pointing, also when imagery of the Earth's surface is used for cartographic applications). Precision pointing capability is the result of spacecraft stability through suitable attitude sensing and control mechanisms (some systems may include vibration control, elimination of alignment errors due to ther-

2088) H. J. Koenigsmann, G. Gurevich, "AttSim, Attitude Simulation with Control Software in the Loop," Proceedings of the AIAAIUSU Conference on Small Satellites, Aug. 23-26, 1999, Logan UT, SSC-IIa-5


mal distortions, etc.). In general structural stiffness ofthe platform is an important prerequisite for a stable pointing environment. There are several classes of instruments with regard to pointing capability:

• Rigid-body instrument pointing or simply body pointing. This refers to a no-instrument-pointing capability relative to the platform. Most observation instruments on a spacecraft platform are fixed, they point into a constant direction (nadir, off-nadir, limb, zenith, etc.), their FOV (Field of View) provides a sufficient scan capability (for instance in the cross-track direction, and/or in the height direction) to measure all resolution cells in a swath.

Some SIC with body-pointed (fixed) instruments are able to employ maneuvers to turn the entire SIC into a desired direction (example: IKONOS-1) thereby extending the field of regard considerably for observations outside of the normal swath width. SIC with relatively small masses ( microsatellites) are most suited for this choice of pointing implementation.

• Instrument pointing relative to the platform. This class of sensors performs inertial pointing/tracking of a star or simply pointing/tracking of the sun or the moon. Some observation instruments need to be kept pointed for relatively long periods of time with extraordinary precision at faint celestial bodies. However, most instruments in this class are attitude sensors (such as: gyroscopes, magnetometers, horizon sensors, star or sun sensors, star trackers, accelerometers), their measurements serve as input for the on-board attitude control subsystem. The pointing knowledge bounds of a platform are always smaller than the actual pointing control bounds.

Instrument pointing capability relative to the platform. These are observation instruments (imager, etc) performing fairly quick slew maneuvers, for instance in the alongtrack direction, to obtain stereo imaging.

Platform or Instrument Pointing Knowledge Pointing Accuracy (Control) TIROS-N 0.1° Spot-1 to -3 0.1° ENVISAT <0.03° < 0.1° (3 sigma) GP-B (relativity mission) < 20 milliarcseconds ( rms) UoSAT 2-3° (rms) gravity-gradient boom system DMSP (Block 50-3) 0.01° (three orthogonal gyros) SOHO 1 arcsecond (sun pointing over a period of 1.5 min) TRACE 20 arcseconds (correction for pointing jitter) Landsat-7 45 arcseconds 180 arcseconds MSX <0.1° (post-processing knowledge of91lrad) GF0-1 0.25° (3 sigma)_ Microlab-1 ±2° gravity gradient boom system IPS (Shuttlel ± 1.2 arcseconds CERES (on EOS) 180 arcseconds MISR (on EOS) 90 arcseconds Sea Winds 500 arcseconds OSA (on CRSS, also re- Rms ground location accuracy: ferred to as Ikonos-1) 2m relative (with ground control points)

12 m absolute (without the use of control points)

Table 563: 'JYpical pointing parameters of a few satellites/instruments

SAR's capability to form good imagery relies significantly on the stability of the platform and, if the stability is not satisfactory, the precise knowledge of attitude information can be used to correct for orbital effects. On-board accurate and precise attitude/position determination is required, and in case of interferometry, most demanding. The baseline knowledge required is in the order of millimeter and the attitude of the baseline in the order of several arcseconds.


In an effort to achieve very precise aiming, ESA built a Spacelab system by the name of IPS (Instrument Pointing System - first flown on STS-51-F as Spacelab-2 in July/Aug. 1985).2089) This three-axis gimbal pointing system provides precision pointing and tracking capabilities by establishing an inertially stable base from which stellar, solar, and Earth observations can be made (maintenance of pointing stability is within ± 1.2 arcseconds ). - In the same context, MACE (Middeck Active Control Experiment) is a NASA precision pointing system (built by MIT, LaRC, LMSC, eta!.) flown on Shuttle flight STS-67 in March 1995, with the objective to explore high precision pointing and vibration control of future spacecraft and satellites. MACE extends conventional rigid-body instrument pointing to include flexible modes. Tests were conducted on the free-floating MACE platform to measure how disturbances caused by a payload impacts the performance of another nearby payload which is attached to the same supporting structure. MACE accomplishments: a) About 50 LaRC control systems were experimentally evaluated on-orbit, b) a reduction of at least 19 dB was achieved in the vibration levels, and c) MACE was able to synthesize and evaluate new control designs during the STS-67 flight. 2090) 2091) 2092)

Spacecraft/platform stabilization. Techniques that control the orientation (attitude) of the spacecraft in orbit with respect to certain known references. Several of the methods in use are:

Single-spin stabilization. The whole spacecraft body rotates about the axis of the principal moment of inertia (acting like a gyroscope). These satellites cannot have oriented antennas, a severe drawback for certain applications.

Dual-spin stabilization. A configuration in which the spacecraft consists of two parts: the platform, which is oriented toward the Earth, and the rotor, which rotates about the principal axis of the S/C thereby providing gyroscopic stiffness (example: Meteosat).

Three-axis stabilization. A configuration in which the entire spacecraft is oriented toward a particular direction (usually toward the Earth in one dimension and aligned to the flight path in the other dimension). The control torques for attitude control are provided by a combination of reaction/momentum wheels, magnetotorquers, torque rods, gimbal system, and/or thrusters. In this concept, the rotating reaction wheels are able to absorb torque and momentum, while magnetic torquers or thrusters are used of allowing the wheels to slow their rotation rate. The same attitude control function may also be provided by an all-thruster system.

Gravity gradient stabilization (passive stabilization method). A spacecraft consisting of two masses (main mass and small mass) that are connected by a rod or a boom. This two-mass arrangement produces a gravity gradient along the boom axis and an associated small torque which is employed for spacecraft orientation. This technique is normally used along with magnetic torquing (yet another passive stabilization method) for better attitude control of small satellites (mini, micro, or nanosatellites ).

Space weather. This term refers to the conditions in space that affect the Earth and its space environment. Space weather is a consequence of sun behavior, the nature of Earth's magnetic field and atmosphere (in particular the ionosphere and magnetosphere), and Earth's location in the solar system. The solar wind, propagating against the Earth's magnetic field and interacting with it, shapes the near-Earth space environment. The response of the Earth's space environment to the solar wind is termed 'space weather.' Space weather can influence the performance and reliability of spaceborne and groundbased technological systems (power and communication systems) and can endanger human life and health

2089)http://www.msfc.nasa.gov/mol/description/ips/ips.html 2090) http:/ /sun-valley.stanford.edu/users/howjo/mace.html 209l)K. K. Denoyer, R. S. Erwin, R. R. Ninneman, ':Advanced SMART Structures Flight Experiments for Precision

Spacecraft," Acta Astronautica, Vol. 47, No 2-9, 2000, pp. 389-397 2092)1. A. Woods-Vedeler, L. G. Horta, "On-Orbit Application of H-Infinity to the Middeck Active Controls Experi

ment: Overview of Results," AAS,l996-189


( spacewalks of astronauts). Other effects are: aurora and changes of climate. The space environment hazards that spacecraft and mission designers and operators need to be concerned with are: 2093)

Solar environment. The solar environment, directly or indirectly, effects all the other hazard environments. The solar activity levels, which follows an 11-year cycle, is a directly contributing factor which interacts to the radiation, thermal and plasma environments. The increased energy output from the Sun during its active periods heats the Earth's atmosphere and causes it to expand, which can effect the impact and neutral atmosphere environments, as well. Magnetic environment. The fields generated by the magnetic environment can directly interact with spacecraft. This is often taken advantage of in the attitude control subsystems, which can employ magnetometers and magnetic torque rods. The magnetic environment is also a major factor in determining the radiation and plasma environments around the Earth. Radiation environment. The radiation environment is principally composed of naturally occurring charged particles trapped in the Earth's magnetic field (also known as the Van Allen belts). Energetic solar particles and galactic cosmic rays also contribute to the natural radiation environment. Thermal environment. The thermal environment consists of thermal energy flux from the sun, the solar energy reflected back into space (and towards the spacecraft) from the Earth, referred to as albedo and the direct longwave thermal emission of the Earth due to its temperature, sometimes referred to as Earthshine. Impact environment. The impact environment consists of material from natural occurring micrometeoroids and from man-made debris flux. Due to the high relative velocities, even tiny particles can cause direct physical damage to the satellite structure and solar panels and can also induce damaging electrostatic discharges. Plasma environment. The plasma environment is mostly composed of charged particles (electrons) with energies too low to be a radiation hazard. However, these particles can strike and deposit themselves on external surfaces of the spacecraft or penetrate through the surface and deposit on internal components, causing electrostatic charge build-up. This charge can build up to high enough levels to create electrostatic discharge hazards that can damage spacecraft electronic components. Neutral atmosphere environment. The neutral atmospheric environment is the residual atmosphere remaining at spacecraft altitudes. The neutral atmosphere can contain atomic oxygen, which can damage the materials used on the spacecraft. Other residual atmospheric chemicals can also react with materials or be a source of contamination for optical systems.

Spatial frequency. Representation of an object or an image as a superposition of sinusoids (Fourier components).

Specific impulse. The specific impulse (lsp) of a thruster is the impulse (a force applied for a certain time) exerted with 1 kg of propellant. Therefore the units for specific impulse are Newton-seconds per kilogram (Ns/kg). By inserting the units of a Newton (lN = 1 kgm/s2), the numerical value of the specific impulse also corresponds to the effective exhaust velocity ( m/s) of the gas exiting the thruster in a vacuum.

Speckle. Refers to the phenomenon of a strong variation of echo signals from one resolution cell to another occurring in radar imaging (it is sort of a granular noise that affects the SAR images). Speckle occurs because the echo received consists of the sum of contributions of point targets in a each resolution cell, in continuously changing combinations (see also chapter 0.8.4). Speckle is caused by the random interference of wavelets scattered by the microscopic fluctuations of the object surface within a resolution cell. The presence of

2093) M. Enoch, et al., "An Integrated Space Environment Analysis Tool (SEAT)," Proceedings ofthe 13th AIANUSU Conference on Small Satellites, Aug. 23-26, 1999, Logan UT, SSClJ9-IIa-6


speckle in an image decreases the radiometric resolution, and thus reduces interpretability of the image (reduction in detail). Usually, filters are used to reduce the effects of speckle.

Spectra (of dispersion).Common methods are: (see also Table 812)

Refraction: prisms are used to break up or disperse electromagnetic radiation into its component colors. The path of the radiation bends (refracts) when it passes from one medium into another. Diffraction: a lightwave breaks up into waves travelling in all directions as it strikes a surface. Diffraction gratings are composed of closely spaced transmitting slits on a flat surface (transmission gratings), or alternately reflecting and nonreflecting grooves on a surface (reflecting gratings). Interference: see Interferometer.

• Filter (electronically tunable filters) • Filter (mechanical) • Filter (mask)

uv Ultraviolet: 0.01 - 0.38 11m FUV Far Ultraviolet: 90- 125 nm EUV Extreme Ultraviolet: 40 - 90 nm (also abbreviated as XUV)

VIS Visible:0.4 - 0. 7 11m NIR Near infrared: 0.7- 1.3 11m VNIR Visible/Near infrared: 0.4- 1.3 flm, -the predominant mode of energy detection is

that of reflected sunlight SWIR Short -Wave infrared: 1.3 - 3 11m - the predominant mode of energy detection is that

of reflected sunlight MWIR Mid-Wave infrared: 3 - 6) 11m -the detected energy is a mixture of solar reflected and

thermally emitted radiatiOn TIR Thermal infrared: 6-14 11m (also referred to as LWIR)- practically all energy re-

ceived (detected) is attributed to thermal emission VLWIR Very Long-Wavelength Infrared{l4- 30 11m) FIR Far infrared: 10- 1000 11m (note: 1000 11m = 1 mm). The TIR range is practically the

lower portion of the FIR range. MW Microwave region: 1 mm - 1 m \ <300 GHz frequencies < 300 MHz) -the detected

energy is of microwave ( therma ) emissions. Since microwave sensors do not depend on solar illumination the observations are virtually independent of aerosols and also much less affected by clouds (cirrus) than sensors operating in IR or VIS.

Table 564: Spectral regions offrequently-used acronyms

Spectral and spatial purity. An evaluation of the quality of radiometric measurements in the spectral and spatial domains.

Spectral band. An interval in the electromagnetic spectrum defined by two wavelengths, two frequencies, or two wavenumbers. Note: The so-called optical spectrum extends from 0.01 ~m to 1000 ~m, i.e., from the UV to the FIR region inclusively. This is followed by the microwave region.

Spectral resolving power. Ratio of A/!1/.. (see also an example under Wavenumber).

Spectral signature. Quantitative measurement of the spectral properties of an object at one or several wavelength intervals.

Spectrometer. An instrument connected to a telescope that separates the light signals into different wavelengths or frequencies, producing a spectrum (thus permitting an analysis of the spectral content of the incident electromagnetic radiation). Usually, only a relatively small portion of the spectrum is measured by an instrument. Some spectrometer types are:

1) Dispersive systems: A class of spectrometers using the dispersive principle to separate radiation into its narrow-band components (spectral discrimination). A dispersive imaging spectrometer can only support one dimension of imaging (along the slit); the


other dimension is used for spectral dispersion. Images are built up by making successive exposures; hence, images are stacked side by side. This is done either by using the motion of an aircraft or spacecraft (pushbroom imaging) or by the use of a sidewaysscanning mirror (whiskbroom imaging). See also 0.3 and 0.6.

Prism spectrometer. From a historical point of view, glass prisms were first used to break up or disperse light into its component colors. The path of a light beam bends (refracts) as it passes from one transparent medium to another, e.g., from air to glass. A prism is used, along with collimating andre-imaging optical and mechanical components, to disperse light for spectral discrimination. Grating (diffraction) spectrometer. A grating is used (along with collimating and re-imaging optical and mechanical components) to disperse light by diffraction for spectral discrimination. The spectral dispersion is stated, for example 2-4 nm/mm at 300 nm, and the resolution is 0.5 nm. In a wedge spectrometer spectral discrimination occurs in a focused beam

2) Filter Spectrometers (nondispersive systems). Filters are used to control the spectral bandwidth of the radiation that is allowed to reach the detector system. Narrowband filters are in the order of 1-2 em -1.

Filter-wheel technique. Allows the selection of up to n discrete spectral bands. Bandpass filter technique. Allows the transmission of only a narrow band of frequencies (the otherfrequencies are blocked out). The spectral width ofthis filter is characterized by its bandwidth. A typical bandpass filter instrument is TM on Landsat Filter mask technique in which the spectral separation filters are mated to the detector array to achieve two-dimensional sampling of the combined spatial/spectral information passed by the filter. A typical instrument of this type is WIS (Wedge Imaging Spectrometer) Dichroic systems. A filter method allowing selective absorption in crystals of electromagnetic radiation vibrating in different planes (usually filtering is based on wavelength). The dichroic principle is applied to beam splitters and filters. Interference filter. A filter reflecting radiation selectively in a narrow spectral band

3) Fourier'fransform Spectrometers (FTS, nondispersive systems). An FTS system provides a conventional spectrum, but with greater speed, resolution and sensitivity. This class of spectrometers separates the incoming broadband spectrum into narrow-band components with the use of an interferometer. An incoming wavefront into the interferometer is divided by a beam splitter (semitransparent surfaces). Beams produced in this way travel two different paths, then recombine (superposition principle), creating an interferogram. This interferogram (a function of signal intensity versus time) is normally digitized and converted to an absorption spectrum by means of a Fourier transform. Instruments with high resolving power often use interferometers in series with grating instruments. FTS can be designed to cover all spectral regions from the radio frequency to the UV.

4) Correlation Spectrometers, also referred to as NDIR (Non-Dispersive Infrared) spectrometers. A correlation spectrometer is a device for a gas-specific investigation that correlates the spectral signatures of the species to be analyzed with reference spectra.

5) AOS (Acousto-Optical Spectrometer). The principle of an AOS is based on the diffraction of light at ultrasonic waves. A piezoelectric transducer, driven by the RF-signal (from the receiver), generates an acoustic wave in a crystal (the so called Bragg-cell). This acoustic wave modulates the refractive index and induces a phase grating. The Bragg-cell is illuminated by a collimated laser beam. The angular dispersion of the diffracted light represents a true image of the RF-spectrum according to the amplitude


and wavelengths of the acoustic waves in the crystal. The spectrum is detected by using a single linear diode array (CCD), which is placed in the focal plane of an imaging optics.

6) Heterodyne Spectrometers (nondispersive systems). See Heterodyning.

7) Lidar Spectrometers.

8) etc.

Spectrometry. In remote sensing the detection and measurement of radiation spectra of a target (area or volume). Each spectra has a characteristic pattern of absorption and emission bands. Comparison of these spectra against reference spectra provide information on the target's material composition. Imaging spectrometry refers to the simultaneous acquisition of images in many contiguous spectral bands.

Spectroradiometer. A combination of spectrometer and radiometer for measuring the energy distribution of emitted radiation.

Spectroscopy- differential absorption spectroscopy. A technique that uses two frequencies emitted by the same laser or by different lasers to perform measurements of the concentration of a gas along a given line of sight. The frequency of one laser signal is tuned to the frequency of the center line of the absorption feature; the frequency of the other laser signal is tuned aside from this feature. The difference in the amount oftransmitted light at these two frequencies is the quantity that is being sought.

System Technology Spectral Wavelength Moving Parts Simultaneous Through-Resolving Range Acquisition of all put

Power A/liA spectral bands Grating 102- 105 Narrow no yes low (CCD detectors) (optics-limited) Prism 10L- 10.J Narrow no yes low

(optics-limited) Fourier Transform 106 Broad yes (no, depend- yes very high Spectrometer (FTS) I (detector-limited) ing on type) Filter (electronically JOL Narrow no no very high tunable) (optics-limited) Filter (mechanical) 10.J Broad yes no very high

I (detector-limited) Filter (mask) 102 Narrow no yes very high

(optics-limited) Filter (mask) 102 Broad WIS I (detector-limited)

no no very high

Table 565: Overview of some spectrometer technology characteristics

Spectroscopy - imaging. Imaging spectroscopy is the acquisition of images, where for each spatial resolution element (pixel) in the image a spectrum of the energy arriving at the sensor is measured. These spectra are used to derive information based on the signature of the interaction of matter and energy expressed in the spectrum.

Spectrum. Refers generally to the intensity distribution of electromagnetic radiation as a function of wavelength, wavenumber, or frequency (see Figure 413).

Spread-spectrum technology. A transmission technique that allows multiple senders and receivers to share the same portion of the spectrum (bandwidth) by having each sender encode its transmission in a unique way decipherable by only its intended receiver. Part ofthis technique is used in GPS (see chapter H.4) and GLONASS (see chapter H.3) communication. Spread spectrum technology is also used for PCS (Personal Communication Services) via satellite on such systems as 'Iridium' and 'Globalstar.' The spread-spectrum technology allows communication satellites to capture and transmit signals that normally would be lost because the original signals were too weak or had too much interference. The wide band-


width of the technology (about three orders of magnitude higher than normal radio frequencies) make it difficult to intercept the signal by an unauthorized party. The feature of low interception probability is attractive for many communication applications.

Squint. The term is used to describe an oblique pointing geometry of a sensor. For instance, a typical SAR pointing geometry is in the cross-track direction, normal to the flight path. Squinting occurs when the antenna beam is pointed forward or backward from this orthogonal direction.

Standing wave. A wave that is stationary with respect to the medium in which it is embedded, e.g., two equal gravity waves moving in opposite directions.

Station keeping. Refers to the maintenance of a geostationary satellite in its assigned orbita! slot with regard to position and orientation (attitude). Orbital drifts are due to small gravitational effects ofthe sun and the moon as well as to an inhomogeneous Earth. The physical mechanism for station keeping is the controlled ejection of hydrazine gas by command from a control center.

Steradian (sr). A unit of solid angle measure in the International System, defined as the solid angle of a sphere sub tended by a portion of the surface, whose area is equal to the square of the sphere's radius. The total solid angle about a point is 4:rt steradians. The term steradian is derived from the Greek for 'solid' and 'radian'- a steradian is, in effect, a solid radian.

Stereoscopy. The spatial three-dimensional or 'stereo' observation of related 2-D images, showing the same object under different viewing angles. Stereo images are very appropriate for map-making and for many other applications (flight simulators, etc.). The image combination of a target area may either result from, say, three cameras of an instrument pointing into the forward, nadir and aft directions, respectively, of a subsatellite track, or from a single gimbaled camera, performing along-track imaging by pointing into the forward, nadir and aft directions successively. Stereo images offer better surface relief mapping capabilities than do regular 2-D images.

Store-and Forward (S&F). A non-real-time communication technique between a LEO satellite and its ground segment (often used for Data Collection Systems, e-mail systems, etc.). In this setup the originating ground station (or terminal) sends a digitized message to the LEO satellite; the satellite intermittently stores the message in an on-board storage system, and the destination ground station later receives the message when the satellite footprint is in its view. Multiple small satellites in polar LEO increase the message traffic capacity and reduce delivery delays.

Stratopause. Stratosphere-mesosphere boundary (at about 50-55 km in altitude) where a relative temperature maxima is found (see Figure 410).

Stratosphere. Region of the atmosphere between the troposphere and mesosphere, having a lower boundary of approximately 8 km at the poles and 18 km at the equator, and an upper boundary of approximately 50 km. Depending upon latitude and season, the temperature in the lower stratosphere can increase, be isothermal, or even decrease with altitude, but the temperature in the upper stratosphere generally increases with height due to absorption of solar radiation by ozone.- The importance of the stratosphere stems from the absorption of the bulk of the solar UV radiation, in particular in the wavelength regions of 290-320 nm. Penetration of this UV radiation to the Earth's surface may be harmful to life. The component in the stratosphere absorbing the bulk of the UV radiation is ozone (03).

Subcarrier. Refers to a second signal "piggybacked" onto the main signal (carrier) to carry an information channel.

Sunspot. A temporary disturbed area in the solar photosphere that appears dark because it is cooler than surrounding areas. Sunspots are concentrations of strong magnetic flux (2000 - 3000 gauss), with diameters less than about 50,000 km and lifetimes of a few weeks.


Sun-synchronous orbit. On orbit is said to be sun-synchronous when the precessing rate of the orbital plane of a satellite, caused mostly by Earth flattening at the poles, is the same as the apparent motion of the sun in the celestial sphere, namely 0.9856°/ day. Such an orbital configuration results in a (nearly) constant local time of ascending node (resulting in observations of a given area on the Earth's surface that are always made at the same local time of the day and the same solar incidence angle). See also chapter 0.12.1.

Superconducting Thnnel Junctions (STJs). Initially under development as efficient detectors of x-rays, they are now being used as single photon detectors in the visible spectrum. STJ (developed at ESA/ESTEC) operates in the range 200-1000 nm with a spectral resolution of 45 nm. Unlike a silicon-based CCD, the niobium-based STJ generates a number of electrons (in the thousands) that depends on the incoming photon's energy. This property eliminates the need for filters or diffraction gratings that lower the overall efficiency.

Superconductivity is the ability of a material to carry electricity with no resistance. Superconductivity was discovered in 1911 by H. K. Onnes in Lei den, Netherlands, just three years after he had succeeded in liquifying helium. Onnes discovered the abrupt and complete disappearance ofresistance in certain metals when they were cooled below the critical temperature Tc of 4.2 K using liquid helium. [Note: instrumentation at liquid helium temperatures is referred to as LTS (Low Temperature Superconductivity) devices].- The value of Tc has changed ever since. The search for a higher Tc began in particular in the 1980s to save the enormous cooling costs at cryo~enic temperatures leading eventually to HTS (High Temperature Superconductivity). 2 4)

Tc = 35 K (April 1986). Karl Alexander Miiller and Johannes Georg Bednorz (IBM Research Laboratory, Switzerland) discovered superconductivity in ~La-Ba)2 Cu04. In 1987, the Nobel Prize in physics was awarded to both researchers. 095)

Tc = 77 K (end of 1986). P. C. W. Chu (University of Texas at Houston) discovered superconductivity in the liquid-nitrogen temperature range. Tc above 90 K (January 1987). M. K. Wu, Chu's former student, achieved stable and reproducible superconductivity above 90 Kin Y1BazCu307-d (Y123), with Tc close to lOOK. Tc = 110 Kand 125 K (1988) for bismuth and thallium superconducting systems respectively Tc = 164 K (1993) for mercury-based compounds under pressure (University of Texas, Houston).

• etc.

The first SQUID (Superconducting Quantum Interference Device) instrumentation appeared in 1964 and was widely used in the field of cryogenics. In the late 1980's, the discovery of high-temperature superconductor materials opened the possibility of introducing the technology in superconducting instruments. Commercial applications of HTS technology in fields such as electric power, transportation, electronics and medicine are appearing in the 1990s. Current applications of HTS include thin-film technology, magnetic resonance imaging (MRI), wireless communication filters, and ultra-fast computer chips. Modern discoveries in superconductivity go far beyond piece-meal improvements in electric devices. They have opened the door on a totally new technology and stretch the imagination to the discovery of new applications.

Surface charge. A satellite immersed in an ambient plasma will come to equilibrium with that plasma by developing surface charges of the proper sign and magnitude to reduce the net current between the satellite and the ambient plasma to zero. The net current consists of a) currents from the environmental flux, b) secondary backscattered electrons and ions, and c) by photoelectrons from any illuminated areas on the spacecraft. As a result of these three processes contributing to the charged particle fluxes, a potential distribution exists about

2094)Special issue: "Superconductivity," Physics Today, March 1986 2095) http://www. physnet.uni- hamburg.de/home/vms/reimer/HTC/HTC.html


the spacecraft so that the net current to the satellite is zero. The potential distribution about a satellite may be rather asymmetric; this depends very much on the satellite geometry, it is also due to the anisotropic distribution of the particle fluxes. 2096)

Surface roughness. Variation in surface height within an imaged resolution cell. A surface appears "rough" to microwave radiation when the height variations become larger than a fraction of the radar wavelength.

Synchronization (sync). Refers to the process of orienting the transmitter and receiver circuits in the proper manner in order that they can be synchronized. Usually a data format is preceded by a sync pattern which is recognized by the receiver.

Synoptic view. A large (inclusive) scene of the Earth's surface, or of an object/target under investigation, allowing a large-scale overview of features or phenomena or relations of a scene in a wider context.

Swath. Width of the imaged scene in the range direction.

Telemetry. A space-to-ground data stream of measured values (normally including instrument science data, instrument engineering data, and spacecraft engineering data) that does not include commands, tracking, computer memory transfer, audio, or video signals.

Telemetry, Tracking and Command (TT&C). Refers to the function of spacecraft operations (monitoring and control of all vital system parameters and tracking of the orbit) by a control center. These TT &C functions are normally completely separate from the spacecraft's user signal (communication satellite) or the measured source (or instrument) data (in case of an Earth observation satellite). Hence, they are also transmitted in a separate band.

Telescience. A technique referring to the control of scientific and/or engineering experiments/instruments from a remote location. Applications include various configurations such as Earth-Earth connections as well as Earth-spaceborne support.

Telescopes (types). Optical telescopes are of two basic types, refractors or reflectors that use lenses or mirrors, respectively, for their light collecting elements. The Galilean (1564-1642) and Keplerian (1571-1630) telescopes are of the refractive type. The Cassegrain and Gregory telescopes are of the reflective type. Reflectors are used in the UV, VIS and IR regions of the electromagnetic spectrum. The name of this type of instrument is derived from the fact that the primary mirror reflects the light back to a focus instead of refracting it.

Cassegrain telescope (design was proposed in 1672 by N. Cassegrain, a French scientist). A reflective telescope in which a small hyperboloidal secondary mirror reflects the convergent beam from the paraboloidal primary mirror through a hole in the primary mirror to an eyepiece in back of the primary mirror (see also Cassegrain antenna). The Cassegrain telescope design is the most frequently used two-mirror system.

Daii-Kirkham telescope. A Cassegrain-type instrument where the primary mirror geometry is an ellipse, while the secondary mirror is a sphere.

• Ritchey-Chretien telescope. A Cassegrain-type instrument. The telescope design reduces the 'coma' (image aberrations) by modifying the primary and secondary surfaces of a Cassegrain telescope. The Ritchey-Chretien telescope employs a hyperboloidal figure for both the primary and secondary mirror thereby providing excellent resolution over a large FOV

• Gregorian telescope. James Gregory (a 17th century Scottish mathematician) devised an arrangement of two concave mirrors. Gregory placed a concave secondary mirror

2096) E. A. Bering, III, R. Kabadi, B. Mcintyre, "High Voltage Spacecraft Charging: Theory and Measurement," Proceedings of the AIAA 2000 Space Conference and Exposition, Long Beach, CA, Sept. 19-21, 2000


outside the prime focus to reflect the light back through a hole in the primary mirror. The spacecraft of the SMM (Solar Maximum Mission), launched in 1980, flies a Gregorian telescope.

Type of Primary Secondary Configuration Telescope Optic Optic 1 - Primary Optic

2 - Secondary Optic 3 - Eyepieces/Correctors 4 - Focus (usually also the image plane)

-=..:::_~ -::..__ . _ o tical ----- -~-p

Newtonian Parabola Diagonal Flat :-- axi Examples: ALF, . -----,-,-- _ ___..,..._ - ==-UV-DIAL 3 c::w

; 4

--------~~3' 3 2c =--=---- -Gregorian Parabola Ellipse - -~-·---=-- - 4 --Example: UVSP -----~~~

Cassegrain Ex: ALISSA, GO- Parabola Hyperbola MOS,ALEX ---- __ ::.-::o --, 1

3 Dall-Kirkham Ex: CAR, CAMS, Ellipse Sphere 2 ( ~ ~ = =- --,..____,~ 4

LASE,MCR ---- ~.:::=-~= ...... Ritchey-Chretien Modified Modified Ex: SEVIRI, EIT, Parabola Hyperbola LEANDRE

~' Schmidt Aspherical Sphere Ex: LFS, OLS, Refractor ~ical

HYDICE ax• -

Figure 423: Basic optical configurations for common types of reflective telescopes

Type of Image Defect Description Spherical aberration Light focuses at different places along the optical axis as a function of radial

position Coma Image size (magnification) varies with radial position in the focal region. Field curvature Off-axis images are not focused on the ideal surface, usually a plane Astigmatism Light focuses at different places along the optical axis as a function of angular

position in the aperture Distortion Focused off-axis image is closer or further from the optical axis then intended Chromatic aberration Shift in the focused image position as a function of wavelength

Table 566: Definition of some basic image aberrations occurring in telescopes 2097)

Newtonian telescope. The primary mirror is of parabolic geometry; the secondary mirror may be a flat plat or a refractive prism. The light beam is diverted to one side for observation.

Schmidt telescope. Bernhard V Schmidt (1879-1935). In 1930, Bernhard V Schmidt of the Hamburg Observatory in Bergedorf, Germany, designed a catadioptric telescope

2097) Encyclopedia of Physical Science and Technology, Academic Press, 1987, Vol. 9 pp. 730-732


with a large FOV to eliminate image distortions (a catadioptric telescope design in corporates the best features of both the refractor and reflector, i.e., it has both reflective and refractive optics). This design compensates for most ofthe spherical aberration by means of an aspherical refractor at the center of curvature.

Theodolite. A surveying instrument used to measure horizontal and vertical angles.

Therrnahiontrol.system. An on-board system which maintains all satellite components within allo"ivnblb temperature limits for all operating modes of the satellite when exposed to the varying thtirmabmvironments throughout its lifetime. Typical thermal loads (forms of environmental heating) are: a) direct solar radiation, b) reflected radiation from the Earth's albedo;re)J:)mission of long-wave IR radiation from the Earth, d) free molecular heating, and:e) charged particle heating.

Thermal Infrared (TIR ). Electromagnetic radiation in the spectral range of 6-20 [.tiD. Many remote sensing applications utilize the 6-12 ~tm range. TIR is emitted energy, whereas NIR (Near Infrared) is reflected energy.

Thermal noise: The 'noisy' detector signal of an infrared sensor caused by the thermal heating of the detector itself. Thermal noise occurs when the system is not sufficiently cooled.

Thermistor. A semiconductor device (sensor) whose electrical resistance varies with temperature.lts temperature coefficient of resistance is high, nonlinear, and usually negative.

Thermoluminescence. A property of certain minerals which causes them to emit light when moderately heated, after electrons are excited into traps by ionizing radiation.

Thermosphere. Outermost layer of the atmosphere, above the mesosphere.

Thin-film technology. Thin films are an important ingredient in all surface technology applications. Surfaces play an important role in nature as well as in technology where smallscale exchange processes take place. Nanotechnology offers a new realm for surface technology in which to operate, providing also new analytical methods for much clearer windows onto nanoscale surface structures. In solar cell applications, thin-film technology refers to dielectric layers for optical anti-reflective coatings, electrical passivation and diffusion barriers. Applications ofthin-film technology abound in such fields as: lithography, deposition, etching, epitaxy, diffusion, optics, sensor technology, etc.

Time Division Multiple Access (TDMA). A process that shares the time domain of a single carrier among many users by assigning to each time intervals in which to transmit signal bursts. In this scheme, all users transmit on the same frequency, each is assigned the total available bandwidth for a limited amount of time. TDMA systems segment time into frames, each frame is further partitioned into assignable time slots.

Tomography (optical tomography). 2098) A diagnostic technique permitting the mathematical reconstruction of 3-D images from a set of 2-D measurements. A typical application are the medical CAT (Computer Aided Tomography) scans which yield the structure of a human body from a set of X-rays. The tomography technique is also finding its way into highspeed applications (high temporal resolution), such as in aero-optical measurements of dynamic turbulent media (simultaneous measurements of the flow field and the optical field provide information of the flow structure in space and time). An application of this technique is the study of phenomena causing degradations in laser beam propagation through atmospheric boundary layer turbulence. In laser transmissions through turbulent media, adaptive optics systems are being used to correct for phase distortion. Adaptive optics systems rely on accurate measurements of the turbulent media and on its ability to distort the beam.

2098)Note: Tomographic methods were first formulated in the1970s as a means of remotely mapping inaccessible re· gions of the human body.


Naturally, the microwave region of the spectrum may also be used for tomographic studies. For instance, the basic concept in CIT (Computerized Ionospheric Tomography) research is to use LEO satellites as moving transmitters and an array of ground receivers to measure TEC (Total Electron Content) in the ionosphere.

Total Solar Irradiance (TSI). The total solar irradiance along with Earth's global average albedo determines Earth's global average equilibrium temperature. Because of selective absorption and scattering processes in the Earth's atmosphere, different regions of the solar spectrum affect Earth's climate in distinct ways. To place the 11-year sun cycle into perspective, the sun's TSI is about 1370 Wm·2 in space (i.e. in low Earth orbits of spacecraft). Since the intercepted radiation is distributed over the surface of the Earth, the average solar radiation at the top of the atmosphere is 1/4 of this, or about 340 wm-2; hence, a variation of 0.1% corresponds to 0.34 wm-2. 2099) Planetary albedo scattering reduces this further to about 0.24 Wm·2 (approximately 20-25% of the TSI is absorbed by atmospheric water vapor, clouds, and ozone, by processes that are strongly wavelength dependent. Ultraviolet radiation at wavelengths below 300 nm is completely absorbed by the Earth's atmosphere and contributes the dominant energy source in the stratosphere and thermosphere, establishing the upper atmosphere's temperature, structure, composition, and dynamics). Even small variations in the sun's radiation at these short wavelengths lead to corresponding changes in atmospheric chemistry. Radiation at the longer visible and infrared wavelengths penetrates into the lower atmosphere, where the portion not reflected is partitioned between the troposphere and the Earth's surface, and becomes a dominant term in the global energy balance and an essential determinant of atmospheric stability and convection. Thus it is important to accurately monitor both the TSI and its spectral dependence. 2100)

Trace gas. A minor constituent of the atmosphere. The most important trace gases contributing to the greenhouse effect are water vapor, carbon dioxide, ozone, methane, nitrous oxide, and chlorofluorocarbons. Other trace gases include ammonia, nitric oxide, ethylene, sulfur dioxide, methyl chloride, carbon monoxide, and carbon tetrachloride.

Tracking system. Tracking is the process of following a moving object. Tracking system is a general name for an apparatus, such as a tracking radar, used to follow and record the position of objects (airborne or spaceborne ). A theodolite and an observer form, for instance, an optical tracking system which is used in pilot balloon runs.

Transceiver. A term made up of the words 'transmitter' and 'receiver' of a signal transmission system. Since each side of a two-way system requires both functions, they are provided in one unit.

Transducer. A device chancing one form of signal energy into another, such as a microphone, a thermocouple, a photocell, etc.

Transmittance (transmissivity). The ratio of power transmitted through a layer of a medium to the power incident upon it.

Transmitter. An electronic device consisting of an oscillator, modulator and other circuits which produce a wave signal for radiation by an antenna.

Transponder. A combined receiver and transmitter system (usually part of a communications system of a satellite) whose function is to transmit signals automatically when triggered by an interrogating signal.

Traveling wave tube. A microwave power generating tube that accelerates electrons by varying a magnetic field between cathode and anode to set up waves of electron density.

2099) G. C. Reid, "Solar Variability and the Earth's Climate: Introduction and Overview," pp. 1-11 in Solar Variability and Climate, Editors: E. Friis-Christensen, C. Frohlich, J.D. Haigh, M. Schussler and R. von Steiger, Kluwer Academic Publishers, ISBN 0-7923-6741-3, 2000

2100) http://lasp.colorado.edu/sorce/


Tropical year. The interval of time between two successive vernal equinoxes. It is equal to 365.242 mean solar days.

Tropopause. Boundary between the upper troposphere and the lower stratosphere that varies in altitude between approximately 8 km at the poles and 18 km at the equator. The temperature gradient of the tropopause goes to zero (a relative temperature minima exists).

Troposphere. Lowest atmospheric layer, between the surface and the tropopause (lowest 8-15 km of the atmosphere, depending on latitude). The troposphere is characterized by decreasing temperature with height, large vertical motion, and large water vapor content. This is the region where most of the 'weather' occurs.

Uplink. Refers to the communication path direction from a ground station to a satellite. The information in this uplink is usually used for commanding of a subsystem (in general there are also uplinks in tracking systems, etc). In very elaborate communication systems with intermediate geostationary transmission satellites, the term 'uplink' is usually replaced by 'forward link' to avoid confusion.

Upwelling. The vertical motion of water in the ocean by which subsurface water of lower temperature and greater density moves toward the surface of the ocean. Upwelling occurs most commonly along the western coastlines of continents, but may occur anywhere in the ocean. Upwelling results when winds blowing nearly parallel to a continental coastline transport the light surface water away from the coast. Subsurface water of greater density and lower temperature replaces the surface water, and exerts a considerable influence on the weather of coastal regions. Carbon dioxide is transferred to the atmosphere in regions of upwelling. This is especially important in the Pacific equatorial regions, where 1 to 2 gigatons of carbon per year may be released to the atmosphere. Upwelling also results in increased ocean productivity by transporting nutrient-rich waters to the surface layer of the ocean. - The term 'upwelling' is also used in the context of 'upwelling radiation.' This refers to radiation (from the Earth's surface and from the atmosphere) observed from an airborne or spaceborne sensor.

UTM (Universal Transverse Mercator Projection). A widely used map projection which employes a series of identical projections around the world in the mid-latitude areas, each spanning six degrees of longitude and oriented to a meridian. The UTM projection preserves angular relationships and scale, it easily allows a rectangular grid to be superimposed on it.

Van Allen Belt. Regions or belts in the Earth's magnetosphere (at about 1.4-1.5 RE and 4.5-6 RE) where many energetically charged particles from the solar wind are trapped in the Earth's magnetic field.

Vegetation index. A mathematical algorithm of reflection values (reflectances, digital pixel values) in different spectral bands, used to estimate vegetation characteristics. Such analgorithm also serves to correct undesirable influences, such as differences of soil reflectance, atmospheric influences, etc. - In physical terms vegetation indices are radiometric measures of vegetation usually involving a ratio and/or linear combination of the red and NIR regions. Vegetation indices serve as indicators of relative growth and/or vigor of green vegetation, and are used as intermediaries in the assessment of various plant biophysical parameters, such as leaf area index, percent green cover, green biomass, and fractional absorbed photosynthetically active radiation (FPAR). The spectral vegetation index concept and its universal generality has its roots in Landsat data interpretation.2101) As a consequence there are now a multitude of defined spectral vegetation and soil indices in existence. They are all derived, at least in part, by considering the contrast between visible (VIS) and near-infrared (NIR) spectral reflectance from land

2101)S. N. Goward, D. L Williams, "Landsat and Earth Systems Science: Development of Terrestrial Monitoring," PE&RS, July 1997, pp. 887-900


surfaces. For typical broadband VIS/NIR measurements, green vegetation foliage produces stepped reflectance, with low VIS and high NIR reflectance, a result of pigment absorption in the VIS region and strong light scatter from cell walls in NIR.

Vernal equinox. The point of intersection between the ecliptic and the celestial equator, where the sun crosses from the south to the north (it is in fact the ascending node of the sun's orbit). The vernal equinox marks the beginning of spring for the northern hemisphere.

Very Long Baseline Interferometry (VLBI). In radio astronomy, the use of a system of two or more antennas placed several hundred or even several thousand kilometers apart, which are operated together as an interferometer. VLBI techniques are also employed in the field of Solid Earth Physics (geodynamics) for determining plate motions with accuracies of better than 1 em/year. VLBI systems offer a superb tie to an inertial celestial reference frame based on extragalactic radio sources, which in turn is used to maintain the terrestrial reference frame.

Video. In general used to mean television, or a system used to communicate the television image. Specifically, pertains to the bandwidth and spectrum position of the signal which results from television scanning and which is used to reproduce a picture. Video images do not have the detailed resolution of film, but offer the advantage of immediate processing capability. This is particularly important in time-sensitive applications.

Vidicon. A generic name for a camera tube of normal light sensitivity. It outputs an analog voltage stream corresponding to the intensity of the incoming light.

Viewing angle. See look angle.

Water vapor. A very important constituent of the atmosphere. Its amount varies widely in space (vertical and horizontal) and time. The troposphere is the domain of water vapor, with about half of all the atmospheric water vapor in a layer below 2 km (only a minute fraction is above the tropopause). Water vapor is the major vehicle of atmospheric energy transport, a regulator of planetary temperatures and of rainfall.- The amount of water vapor in a given air sample may be determined in a number of different ways, involving such concepts as absolute humidity, mixing ratio, dew point, relative humidity, specific humidity, and vapor pressure.

Water-vapor absorption bands. Wavelength bands where water vapor -free or bound - absorbs radiation to a high degree. Absorption bands in theIR region are near 1.4 !J-ill, 1.8 !J-ill, 2.7 !J.ID, 6.3 !J.ID (strong), 11 !J.ID, and 30 !J.ID.

Wavefront. A three-dimensional surface in space for which the field radiated by the antenna has the same phase at all points. At a large distance R from the antenna, the wavefront is a spherical surface with radius Rover the angular window established by the antenna pattern. For most geometries encountered in remote sensing, the wavefront may be approximated by a plane tangent to the spherical surface.

Wavenumber (v). The number of waves per em (the reciprocal ofthe wavelength). v = 1/A. A wavenumber of 10,000 corresponds to a wavelength (A) of 10·4 cm-1, or to a wavelength (A) of 1 !J-ill. Conversion of a wavenumber resolution 11v into a wavelength resolution 11A: v= 1/A=I11vi=I11AI ft2=111AI=I11vl A2

Example: convert the wavenumber resolution 11v=20 cm-1 into a wavelength resolution for the spectral range of 400-800 nm. I11A I= l11v I A2 = 20cm-1x(400nm)2=2x10-6 nm·1 x160000nm2= 0.32nmforA=400nm. I11A I= l11v I A2 = 20cm·1 x(800nm)2=2x 1Q·6 nm·1 x640000nm2= 1.28 nm forA=800nm.

In this context belongs also the spectral resolving power, which is defined as the following ratio: f.../ 111... Example: find the spectral bandwidth for a spectral range from 1.0-2.5 !J-ill when the spectral resolving power (A/11A) of the instrument is given as 250.


A/.. = /../250 = 1 !lm/250 = 0.004 !!ill or 4 nm at the lower bound of the spectral range A/.. = A/250 = 2.5 !lm/250 = 0.010 !liD or 10 nm at the upper bound of the spectral range.

WGS-72 (World Geodetic System 1972) an Earth-centered datum ofDMA (Defense Mapping Agency of US DoD). WGS-72 was preceded by WGS-60 and WGS-66. A principal objective of WGS is to allow referencing of local geodetic systems to a single geocentric system. WGS-72 is the result of an extensive effort (extending over 3 years) to collect satellite, surface gravity, and astrogeodetic data available throughout 1972. These data were combined using a unified WGS solution (a large-scale least squares adjustment).

WGS-84 (World Geodetic System 1984).2102) WGS-84 was also developed by DMA and is an improvement and a replacement for WGS-72. Radar altimeter data from GEOSAT was used to deduce geoid heights from oceanic regions oflatitude ± 70°. Geoid heights were also deduced from a large number of ground-based Doppler stations and ground-based laser satellite-tracking data, as well as surface gravity data. Definition: WGS-84 is a set of parameters for determining geometric and physical geodetic relationships on a global scale. The system includes a geocentric reference ellipsoid, a co ordinate system, and a gravity field model. The ellipsoid is essentially that of the International Union of Geodesy and Geophysics Geodetic Reference System 1980. The coordinate system is a realization of the conventional terrestrial system, as established by the International Earth Rotation Service. 2103)

Wind shear. The rate of change of the wind velocity components with distance.

Window (electromagnetic). Wavelength or frequency region in which the atmosphere is largely transparent to electromagnetic radiation (e.g. optical window, microwave window, etc.).

Window operation. Processing of the (radiation) values of pixels within a predefined window, mostly limited to one spectral band - also called a 'filter.' Examples are convolution filters, variance filters, etc .. The filter output is assigned to the central pixel of the window.

Whiskbroom scanner. A line-scanning optomechanical sensor system.

World Geodetic System 1984 (WGS-84). Refers to a set of parameters established by the US Defense Mapping Agency (DMA) for determining geometric and physical geodetic relationships on a global scale. The system includes a geocentric reference ellipsoid, a coordinate system, and a gravity field model. The ellipsoid is essentially that of the International Union of Geodesy and Geophysics (IUGG) 'Geodetic Reference System 1980.' The coordinate system is a realization of the conventional terrestrial system, as established by the International Earth Rotation Service.

Zenith angle. The angular distance of any celestial object from a given observer's zenith, measured along the great circle of the celestial sphere from zenith to object.

Zodiacal light. A faint glow that extends away from the sun in the ecliptic plane of the sky, visible to the naked eye in the western sky shortly after sunset or in the eastern sky shortly before sunrise. Its spectrum indicates it to be sunlight scattered by interplanetary dust. The zodiacal light contributes about a third of the total light in the sky on a moonless night.

2102)"World Geodetic System 1984," DoD DMA TR 8350.2, September 1987 2103) R. B. Langley, "A GPS Glossary," GPS World, October 1995, pp. 61-63

AppendixB Acronyms and Abbreviations

Units of Measure and some Physical Constants A . . . . . . . . . . . . . ampere - unit of electric current [named after Andre M. Ampere

(1775-1836), French physicist] Ah . . . . . . . . . . . . ampere hour A ............. angstrom - UIJit of length (used in particular for the ~port wavelength

spectrum); 1A= 10-10 m [named after Anders Jonas Angstrom (1814-1874), Swedish physicist and astronomer]

amu ........... atomic mass unit (1.6605402 10-27 kg) are ............ unit of area (1 are = 100m2) arcmin ......... arcminute [1' = (1/60)D] arcsec .......... arcsecond [1" = (1/60)'] au . . . . . . . . . . . . . astronomical unit- unit of length, namely the mean Earth/sun distance

[ = 1.4959787061013 em, which is the semimajor axis ofthe Earth's orbit around the sun (or about 150 million km)]

bar ............ pressure, (1 bar = 105 Nm-2) c .............. speed of light in vacuum (299,792,458 m/s) cd ............. candela (unit of luminous intensity). The candela is theluminous inten

sity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012Hz and that has a radiant intensity in that direction of 1/683 watt per steradian.

em ............ centimeter (unit of length) 1 em = 10·2 m C . . . . . . . . . . . . . . coulomb - unit of electrical charge; 1 C = 1 As [named after Charles

Augustin Coulomb (1736-1806), French physicist. The coulomb is the quantity of electricity transported in 1 second by a current of 1 ampere.

°C ............. degree Celsius [named after Anders Celsius (1701-1744), Swedish astronomer]

dB . . . . . . . . . . . . . decibel - a unit for expressing the signal strength [named after Alexander Graham Bell (1847-1922), Scottish-born American inventor]

dm . . . . . . . . . . . . decimeter (lengtiV 1 dm = 10-1 m E .............. E6tv6s (1 E = 10· s·2). The linear gradient of gravity is defined in units

of E6tv6s, named in honor of the Hungarian physicist Roland E6tv6s (1848-1919)

e V ............ electron volt (1.60217733 10·19 J). A unit of energy, equal to the energy an electron (or proton) would gain when accelerated by 1 volt.

F . . . . . . . . . . . . . . farad - a unit of capacitance [named after Michael Faraday (1791 -1867), English physicist and chemist]. The farad is the capacitance of a capacitor between the plates of which there appears a difference potential of 1 volt when it is charged by a quantity of electricity equal to 1 coulomb.

f . . . . . . . . . . . . . . focal length f/d ............. focal-length-to-diameter ratio GHz ........... Gigahertz (109 Hz) gal ............. unit of acceleration (used in particular in~ravity measurements): 1 gal

= 10-2m s-2 = 1 em s·2; 1 mgal = 10·5 m s· [named after Galilei Galileo (1564-1642), Italian mathematician, astronomer and physicist]

gauss .......... unit of magnetic induction [named after Carl Friedrich Gauss (1777-1855), German mathematician]

H ............. henry- unit of magnetic inductance; 1 H = 1Wb/A or 1Vs/A [named after Joseph Henry, a nineteenth-century US physicist]

Hz ............ hertz- a measure of frequency; 1Hz = 1/s [named after Heinrich Hertz (1857-1894), German physicist]

h .............. hecto (102) h (or hr) ........ hour

1394 Appendix B: Acronyms and Abbreviations ----------------~~--------

h .............. Planck's constant = 6.6260755 x 10·34 Js (joule second) ha ............. hectare (1 ha = 104m2) hPa ............ hectopascal (international standard of pressure, 1 hPa = 100 Pa) Isp ............ specific impulse with a unit Ns!kg. The numerical value of the specific

impulse also corresponds to the effective exhaust velocity ( m/s) of the gas exiting the thruster in a vacuum. See also Glossary.

J .............. joule- unit of work or energy; 1 J = 1 Nm = 1 Ws [named after James Prescott Joule (1818-1889), British physicist]

K .............. degree Kelvin [named after Sir William Thomson (Lord Kelvin, 1824-1907), Scottish engineer, physicist and mathematician]. The degree Kelvm is the unit of temperature determined by the Carnot cycle with the triple-point temperature of water defined as 273.15 K (corresponds exactly to 0 °C).

k . . . . . . . . . . . . . . kilo (1 03) kbit/s .......... kilobit per second (103 bit/s) keY ........... kiloelectron volt (103 eV) kg ............. kilogram (103 g) kg/m3 . . . . . . . . . . density kHz ........... kilohertz (103Hz) km ............ kilometer (103 m) krad ........... kilorad (see rad below) kW ............ kilowatt (103 watt) kWe ........... kilowatt electric (used to distinguish electrical power from thermal

power) L . . . . . . . . . . . . . . liter (volume) 11 = 1 dm3 [the symbol for liter is capitalized (when alone

by itself) to avoid confusion with the number 1] lm ............. lumen ( cd sr) luminous flux. The lumen is the luminous flux emitted in a

solid cangle of 1 steradian by a uniform point source having an intensity of 1 candela.

lx .............. lux (lm/m2) illumination M ............. Mega (106) Mbit/s .......... Megabit per second (106 bit per second) MeV ........... Megaelectron volt (106 eV) MHz ........... Megahertz (106 hertz) m ............. meter m ............. milli (10-3) m2 ............. area (square meter) m3 ............. volume (cubic meter) mb (mbar) ...... millibar min ............ minute mg ............ milligram (l0-3 g) mgal ........... m!ll!~al (l0-3 ~al) mJ ............ mtlhjoule (lO- J) ml ............. milliliter (l0-3 I) mm . . . . . . . . . . . . millimeter (unit of length) 1 mm = 10·3 m mN . . . . . . . . . . . . millinewton mrad ........... milliradian 2104) ms . . . . . . . . . . . . . millisecond m/s ............ meter per second (velocity) ~ .............. micro (10-6) ~m ............ micrometer (l0-6 m) ~rad . . . . . . . . . . . microradian ~s ............. microsecond (l0-6 second) N ............. newton- unit of force; 1N = 1 kgm/s2 [named after Sir Isaac Newton

( 1643-1727), English natural philosopher and mathematician]

2104)An example is given to better visualize the plane angle of a milliradian. The apparent sun disk angle as seen from Earth is 32' 26" (max, or about 30.7 mrad), and 31' 31" (min).

Appendix B: Acronyms and Abbreviations

Nm ............ newton meter (work or energy) n .............. nano (l0-9) nm ............ nanometer (10-9 m) nm .......... .. nT ............ .

nautical miles J1 nm = 1852 m (international)] nanotesla (lO- tesla) unit of magnetic flux density

1395

Q ............ . ohm- unit of electrical resistance; 1 Q = 1 VIA [named after Georg Simon Ohm (1789-1854), German physicist

Pa . . . . . . . . . . . . . pascal - unit of pressure; 1 Pa = 1 N/m2 [named after Blaise Pascal (1623-1662), French mathematician and physicist]

p .............. pico (l0-12) pC ............ picocoulomb go-12 coulomb) pT ............. picotesla (~0:1 tesla& ppb ............ parts per billion (10- ) ppbv . . . . . . . . . . . parts per billion, by volume ppm ........... parts per million (l0-6) ppmv . . . . . . . . . . parts per million, volume pps . . . . . . . . . . . . pulses per second ppt . . . . . . . . . . . . parts per trillion (1 o-12) pptv ........... parts per trillion (l0-12), by volume RE ............ Earth radius= 6378.140 km (mean equatorial radius) rad . . . . . . . . . . . . radian - a unit of plane angular measurement equal to the angle at the

center of a circle subtended by an arc equal in length to the radius rad/s ........... radian per second (angular velocity) rad ............ In the context of radiation shielding, the term "rad" is also used for en

ergy accumulated in matter (dosimetry for the energy absorbed per unit mass of material, usually by ionization processes). A rad is the amount of particle radiation that deposits w-2 J/kg of target material. Besides the "rad" is the "Gray." 1 rad = 1/100 Gray. Note: A Gray is the radiation absorbed dose unit of SI (Systeme Internationale ). 1 Gray = 1 J/ kg ( = 100 rad). Or 10 Gray = 1000 rad = 1krad. 2105) root mean square rms .......... ..

rpm ........... . rps ........... . s ............ ..

revolutions per minute revolutions per second siemens - unit of electrical conductance; 1 S = 1 A/V [named after Wernervon Siemens (1816-1892), German electrical engineer]

s .............. second sr . . . . . . . . . . . . . steradian -a unit of measure of solid angles expressed as the solid angle

subtended at the center of a sphere by the portion of the surface whose area is e~ual to the square of the radius of the sphere

T .. .. .. .. .. .. .. Tera (101 ) TB ............ TeraByte (1012 Byte) THz ........... Terahertz (1012 hertz) tesla (T) ........ unit of magnetic flux density. 1 T = 1 Wb/m2 which corresponds to 104

gauss [named after Nikola Tesla (1856-1943), Croatian-born American inventor]

V ............. volt- unit of electrical potential [named after Alessandro Volta (1745-1827), Italian physicist]

W ............. watt-unitofpower; 1 W = lJ/s[namedafterJamesWatt(1736-1819),a Scottish mechanical engineer and inventor]

Wb ............ weber- unit of magnetic flux [named after Ernst Weber (1901-), Austrian-born US engineer

Wh ............ watt hour (work or energy) Ws ............ watt second (work or energy)

2105)Typical CMOS devices can tolerate 1-10 krad/year. Dose rates for a silicon target are usually stated in g/cm2 or in thickness of aluminum shielding for a given orbit. For a sun-synchronous orbit, about 0.8 g/cm2 (or 4 mm silicon thickness) is needed for a !-year lifetime, and about 3 g/cm2 (13 mm silicon) for a 10 year lifetime.

1396 Appendix B: Acronyms and Abbreviations

General conventions of unit representations:

The symbol "m" is used with various meanings depending on its position and occurrence in a unit. In single-digit instances, the symbol m stands simply for meter. This is also the case in double symbol instances, when m is in last position, like in Nm (newtonmeter), nm (nanometer), or mm (millimeter). When misused in double-digit symbols in first place, like mm (millimeter), ml (milliliter), ms (millisecond), mN (millinewton), etc., then the first small "m" is always used in a diminutive sense referring to "milli" (l0-3).

The term small "k" stands for kilo (103) as in km (kilometer), kg (kilogram), kW (kilowatt), or kbit (kilobit). The capital letter "K," on the other hand, has the meaning of Kelvin, referring to a degree temperature on the absolute temperature scale.

The designations M (Mega), G (Giga), T (Tera), or!! (micro), n(nano), p (pico), etc., in combinations with other units, follow the same logic as outlined above and in Table 568.

Quantity Unit name Unit symbol Length meter m Mass kilogram kg Time second s

Electric current ampere A Thermodynamic temperature kelvin K

Luminous intensity candela cd Amount of substance mole mol

Table 567: Symbols for the seven basic units in the SI system

The basic SI units come in all sizes. Since the SI system is built upon the base 10, the different sizes are base 10 multiples of the basic units as illustrated in Table 568.

Prefix Symbol Multiplication factor Examples

Ex a E lQI~ = 1,000,000,000,000,000,000 Pet a p 1 o1s = 1,000,000,000,000,000 Tera T 101L - 1,0QQ,QQQ,QQQ,QQQ TByte Giga G 10y = 1,000,000,000 GHz, GByte,

Mega M 106 = 1,000,000 MHz, Mbit/s, kilo k 10- = 1,000 km (kilometer), kg (kilogram),

hecto h 10L = 100 hl (hectoliter), ha (hectare) dec a da 101 = 10

100 = 1 deci d 10-1 = 0.1 dg (decigram), dl (deciliter) centi c 10-L = o.o1 em (centimeter), cl(centilitef) milli m 10-3 = o.oo1 mm (millimeter), ml (milliliter)

micro [.1 10-6 = o.ooooo1 [.liD (micrometer), [!g (microgram) nano n 10-Y = o.oooooooo1 urn (nanometer), us (nanosecond) pi co p 10-1L = o.oooooooooo01 ps (picosecond), pf (picofarad)

fern to f 10-1, = o.ooooooooooooo01 fs (femtosecond) atto a 10-1s = o.ooooooooooooooooo1

Table 568: Commonly used prefixes of SI multiples and submultiples

Quantity Unit name Unit symbol (derivation) Force newton ~{(kgms-2)

Energy joule J (Nm) or (Ws) or (kgm252) Energy kilowatt hour kWh (3.6 106 J) Energy electron volt eV (1.610·1Y J) Power watt W (Js-1) or (kgm18-3)

Appendix B: Acronyms and Abbreviations 1397

Quantity Unit name Unit symbol (derivation) Frequency hertz Hz (s-1)

Electrical potential volt V (JC-1) or (WAI) Electrical charge coulomb C(As)

Electrical resistance ohm Q (VA-1)

Electrical conductance siemens S (A v-1)

Electrical capacitance farad F (C v-1) or (As v-1)

Magnetic inductance henry H(WbA-1) or(VsA-1)

Magnetic flux weber Wb(vsY Magnetic flux density tesla T (Wbm-l)

Area square meter ml

Volume cubic meter m3 Volume liter L(lo-3 m3)

Velocity (speed) meter per second ms·1

Temperature degree Celsius oc Pressure pascal Pa (Nm-2) or (kg m·I s·2) Pressure standard atmosphere atm (1.01325 10' Pa) Torque Nm (newton meter)

Electric field strength V m·1 (volt per meter) Magnetic field strength A m·1 (ampere per meter) Plane angle (arc length) degree 1° = (1t/180J rad

arcmin (minute) 1' = (1/6~0 arcsec (second) 1" = Yv6 ir

Thble 569: Derived units commonly used in science and engineering 2106) 2107)

Numbers 3DMA ......... Three-Dimensional Microgravity Accelerometer (Shuttle payload)

A AAAS . . . . . . . . . American Association for the Advancement of Science (Washington

DC) AAE ........... Austrian Aerospace GmbH, Vienna, Austria AAOE ......... Airborne Antarctic Ozone Experiment (1987) AARGOS . . . . . . A340 Atmospheric Research Global Observation System (MOZAIC) AARI .......... Arctic and Antarctic Research Institute (St. Petersburg, Russia) AAS ____ . . . . . . . American Astronomical Society AASE .......... Airborne Arctic Stratospheric Expedition (see campaign survey) ABLE ......... Atmospheric Boundary Layer Experiment (campaign) AC . . . . . . . . . . . . Alternating Current ACC ........... Anthropogenic Climate Change (CLIVAR subprogram) ACCESS . . . . . . . Assembly Concept for Construction of Erectable Space Structure

(Shuttle) ACE ........... Advanced Composition Explorer (NASA, APL, etc., see K.l) ACE-1, -2 ...... Aerosol Characterization Experiment (campaigns) ACE . . . . . . . . . . . Atmosphere Climate Experiment (an ESA mission, A.1) ACEChem . . . . . . Atmospheric Chemistry Explorer (a proposed ESA misson as of 2001) ACES . . . . . . . . . . Acoustic Containerless Experiment System (Shuttle payload) ACORN ....... Airborne Composition Observations in the Region ofthe North-Atlan-

tic-Corridor (P.40.2) ACRES . . . . . . . . Australian Centre for Remote Sensing (Belconnen, Australia) ACSYS ........ Arctic Climate System Study (WCRP program) ACT ........... Applied Coherent Technology, Herndon VA (commercial provider of

remote sensing products, operator of satellites, etc.)

2106) "Symbols and Abbreviations for Electrical and Electronic Engineering," lEE, 1980 2107) R. A. Nelson, "Guide for Metric Practice," Physics Today, Supplement to August 1997 issue, pp. 13--14


ACTS .......... Advanced Communications Technology Satellite in GEO (NASA, Launch: Sept. 1993 by Shuttle Discovery). ACTS advanced considerably the use of Ka-band technology and paved the way for high-speed commercial Ka-band communications.

AID . . . . . . . . . . . Analog/Digital converter ADCP ......... Acoustic Doppler Current Profilers [(U. of Florida, Tokai University,

Hiroshima University, Kyushu University, Japan, and CSIRO), subsurface upward-looking moorings]

ADEN ......... ALOS Data European Node [an ESA initiative involving a number of distributed acquisition facilities capable of receiving ALOS data (SAR and optical) for European users: a) Toulouse (France) with upgraded X-band stations, b) DLR Neustrefitz (Germany) and Libreville (Gabon), c) TSS Tromsoe (Norway) and SSC Sturup (Sweden, d) ASI Matcira (Italy and Maspalomas (Spain)]

ADEOS ........ Advanced Earth Observation Satellite (NASDA, D.l, D.2) ADM .......... Atmospheric Dynamics Mission (ESA Earth Explorer Core Mission) ADPCM ....... Adaptive Differential Pulse Code Modulation (a lossy data compres

sion technique) ADS-B . . . . . . . . . Automatic Dependent Surveillance-Broadcast (an FAA system

installed in aircraft (first prototypes as of 2000). When coupled with GPS, an aircraft's ADS-B unit can continuously broadcast its identification, position, altitude, direction, speed, rate of climb or descend, etc.] ADS-B is a key technology to free flight.

ADSF .......... Automated Directional Solidification Furnace (Shuttle payload) ADV CGBA .... Advanced Commercial Generic Bioprocessing Apparatus (Shuttle) ADV XDT ..... Advanced X-Ray Detector (Shuttle payload) AEAP ......... Atmospheric Effects Aircraft Program (NASA) AEB ........... Agencia Espacial Brasileira - Brazilian Space Agency, Brasilia, Brazil

(since 1994) AEM-1 ......... Applications Explorers Mission- I (see HCMM A.18) AEM-2 ......... Applications Explorers Mission-2 (AS) AERCam/Sprint . Autonomous Extravehicular Activity Robotic Camera Sprint (Shuttle

free-flying camera, first flown on STS-87 (Nov. 19 -Dec. 5, 1997)] AEROCE ...... Atmospheric/Ocean Chemistry Experiment (campaign) Aerospace Corp .. 'The Aerospace Corporation' (since 1960), a US private nonprofit re

search and development center with HQs in El Segundo, CA. Aerospace operates a Federally Funded Research and Development Center (FFRDC) for the Department of Defense (DoD). The primary customer is the Space and Missile Systems Center (SMC) of the US Air Force Materiel Command. The Aerospace Corporation provides engineering services and space technology expertise to DoD space programs and other US government agencies. Other company locations are in the Washington DC area, Colorado Springs, CO, Albuquerque, NM, Sunnyvale CA, VAFB, CA, and at KSC (Kennedy Space Center), FLA.

Aerospatiale .... A French aerospace conglomerate with 38,000 employees, HQ in Paris. Builder of the main stages of Ariane 4 and 5. Manufacturer of satellites and sensors. Three major divisions: Aircraft, Helicopters, and Space & Defense. Spacecraft platforms: Spacebus series.

AES ........... Atmospheric Environment Service (of Environment Canada) AESA ......... Atmospheric Effects of Stratospheric Aircraft (NASA) AF . . . . . . . . . . . . US Air Force AFB . . . . . . . . . . . Air Force Base (US Air Force) AFC ........... Affiliated Data Center (these are institutional facilities that are affili

ated with EOSDIS, in particular NOAA facilities are AFCs) AFE ........... American Flight Echocardiograph (Shuttle payload) AFGL ......... Air Force Geophysics Laboratory (Hanscom AFB, Bedford, MA,

USA) Note: in 1998 AGFL was renamed to "Hanscom Research Site"


AFP-675 ........ Air Force Program 675 (Shuttle payload) AFNOR ........ Association francaise de normalization (French standards institute) AFOSR . . . . . . . . Air Force Office of Scientific Research (an AFRL directorate) AFRL ......... Air Force Research Laboratory (USA). The nine AFRL sites are lo

cated at: Wright Laboratory, Wright-Patterson AFB, Ohio (AFRL HQs, directorates of: Air Vehicles, Propulsion, Directed Energy, and Materials & Manufacturing); Hanscom AFB, MA (Sensors directorate); Phillips Research Site, Kirtland AFB, Albuquerque, NM (Space Vehicles directorate); Rome Laboratory, Griffis AFB, Rome, NY; Edwards AFB, Edwards, CA; Brooks AFB, TX; Eglin AFB, FL; Tyndall AFB, FL; Bolling AFB (AFOSR directorate), Washington DC.

AFSCN ........ Air Force Satellite Control Network (USA) AFSK .......... Amplitude Frequency Shift Keying (modulation technique) AGARD . . . . . . . Advisory Group for Aerospace Research and Development. AGARD

is a NATO agency (with HQ in Neuilly-sur Seine, France), formed in 1954, with the objective to enhance the exchange of aerospace technology within NATO.

AGASP ........ Arctic Gas and Aerosols Sampling Project (airborne campaign) AGC . . . . . . . . . . Antenna Gain Control AGGA ......... Advanced GPS/GLONASS ASIC (ESNESTEC development). As of

the end of 2000 the AGGA chip set is available to European industry, it is manufactured by ATMEL of Nantes, France. It is used in GRAS, in the LAGRANGE GNSS receiver ofLaben SpA, Italy, and in the RIMS stations of the EGNOS program.

AGILE ........ Astro-rivelatore Gamma ad Immagini LEggero (Gamma-ray Astronomical Low-Mass Detecor), an approved ASI mission with a planned launch in 2003

AGL ........... Above Ground Level (usually the altitude of aircraft) AGU .......... American Geophysical Union (a society with over 35,000 members in

over 115 countries. The objective is to advance progress in the Earth, atmospheric, oceanic, hydrologic, and space and planetary sciences.)

AIAA .......... American Institute of Astronautics and Aeronautics (Reston, VA) AIDJEX ....... Arctic Ice Dynamics Joint Experiment (campaign) Airbus Industrie . A consortium of European aerospace companies, founded in 1970.

(partners are: Aerospatiale of France, DASA Airbus of Germany, British Aerospace, and Spain's CASA). Italy's Alenia, Fokker of the Netherlands, and Belairbus in Belgium are associate members who participate in selected programs. Some 32,000 people work directly for Airbus Industrie within the partner companies. Airbus lndustrie is headquartered near Toulouse, France. Builder of civil aircraft (Airbus).

AIRS .......... Autonomous Information Reception Station (see Meteor-3M series) AlP . . . . . . . . . . . . American Institute of Physics AlP ............ Astrophysikalisches Institut Potsdam (Germany) AKR .......... Auroral Kilometric Radiation (ionospheric phenomenon) ALACE ........ Autonomous Lagrangian Circulation Explorer (free-floating ocean

buoys designed to seek a pre-programmed depth; they drift with the ocean currents of that depth, and pop up periodically to report their position to a satellite), see also PALACE

ALE/GAGE .... Atmospheric Lifetime Experiment/Global Atmospheric Gas Experiment (campaign)

Alenia Spazio ... Alenia Aerospazio S.p.A. is a company of the Finmeccanica IRI group, an Italian consortium in aerospace, defense, energy, transportation and automation markets. Partner in many space programs (2500 employees), builder of COSMO-SkyMed. Subsidiaries: Laben S.p.A. (Laboratori Elettronici Nucleari) in Vimodrone (Milano, Italy) since 1958; SSI (Space Software ltalia S.p.A. in Taranto, Italy; QSW (Quadrics Supercomputer World Ltd.) in Rome, Italy; HCSA (Hellenic Company


for Space Applications S.A.) in Paradisos Amarousiou, Italy; EuroSkyWay in Rome, Italy

ALEXIS ....... Array of Low Energy X-Ray Imaging Sensors (LANL, K.3) ALISSA . . . . . . . . I' Atmosphere par Lldar Sur SA!iout (the French sensor was at first pro-

posed by CNES for a Salyut flight) ALMAZ ....... ALMAZ =='rough diamond' (Earth observation series, Russia), D.4 ALOHA ....... One of several communication access methods ALOHA . . . . . . . Airborne Lidar and Observations ofthe Hawaiian Air glow (campaign) ALOS ......... Advanced Land Observing Satellite (DJ) ALPEX ........ Alpine Experiment (campaign) AM ............ Amplitude Modulation (modulation technique of the main carrier) AM . . . . . . . . . . . . Ante Meridiem (US time notation designating morning hours, to dis-

tinguish from PM) AMBIACE . . . . . Amazon Biogeochemistry and Atmospheric Chemistry Experiment

(campaign) AMEX ......... Australian Monsoon Experiment (campaign) AMM .......... Antarctic Mapping Mission (Radarsat) AMOS ......... Air Force Maui Optical Station (Shuttle experiment). AMOS is located

at the summit of Haleakala, on the island of Maui, Hawaii. The Air Force experiment is using the Shuttle orbiter as a calibration target for a ground-based experiment (research for electro-optical sensors)

AMPTE . . . . . . . . Active Magnetosphere Particle Tracer Explorers (cooperative mission of US/ NASA, Germany and UK, K.4)

AMS .......... Alpha Magnetic Spectrometer (Shuttle payload) AMS was first flown on STS-91 (June 2-12, 1998). It IS an anti-matter demonstration, an experiment with internationaf cooperation from: USA, China, Finland, Germany Italy, and Switzerland

AMS . . . . . . . . . . American Meteorological Society AMSAT . . . . . . . . The Radio Amateur Satellite Corporation (worldwide groups of Ama

teur Radio Operators (volunteers, normally organized by country), building, launching and communicating with each other through noncommercial amateur satellites, since 1969, also the name of satellites)

AMTEC ....... Alkali Metal Thermal-to-Electric Converter (Shuttle payload) ANL ........... Argonne National Laboratory (Argonne, IL, USA, a DOE facility, op-

erated by the University of Chicago) ANSI .......... American National Standards Institute ANSTO ........ Australian Nuclear Science and Technology Organization Antrix Corp. . ... Bangalore, India (the commercial marketing arm of ISRO, Antrix is

the distributor of IRS data, etc.) AO ............ Announcement of Opportunity (usually for a sensor on a particular

mission) AOCS . . . . . . . . . Attitude and Orbit Control System AOET ......... Atomic Oxygen Exposure Tray (Shuttle D2 mission) AOS . . . . . . . . . . . Acousto-Optical Spectrometer AOTF . . . . . . . . . Acousto-Optic Tunable Filter (an imaging dispersion technique) APARE ........ Asia/North Pacific Regional Study (campaign) APCF . . . . . . . . . . Advanced Protein Crystallization Facility (Shuttle, see also PCF) APCG ......... Advanced Protein Crystal Growth (Shuttle, see also PCG) APD . . . . . . . . . . . Avalanche Photodiode (detector type) APDA . . . . . . . . . Arctic Precipitation Data Archive APE ........... Airborne Polar Experiment (campaign) APE . . . . . . . . . . . Auroral Photography Experiment (Shuttle payload) APEX . . . . . . . . . Active Plasma Experiment (lntercosmos, K.S) APFO ......... Aerial Photography Field Office (Salt Lake City, UT, USA) APL ........... Applied Physics Laboratory, since 1942, a facility of Johns Hopkins

University (JHU), in Laurel, MD, USA APM .......... Ascent Particle Monitor (Shuttle experiment)


APRS . . . . . . . . . . Automatic Position Reporting System (a protocol used by the Amateur Radio community)

APS . . . . . . . . . . . Active Pixel Sensor APSC . . . . . . . . . . Asia Pacific Space Center APT . . . . . . . . . . . Automatic Picture Transmission (one type of NOAA downlink trans

mission; APT transmits data from two channels of the AVHRR at areduced resolution of 4 km in the VHF frequency band (at 137.50 and 137.62 MHz)).

APV ........... Autonomously Piloted Vehicle (Condor) AR ............ Anthrorack (Shuttle D2 mission) ARAT . . . . . . . . . A vi on de Recherche Atmospherique et de Teledetection (Atmospheric

Research and Remote Sensing Aircraft), ARAT is jointly operated by INSU-CNRS, CNES, DMN (French National Weather Center), and IGN (Institut Geographique National). The aircraft is IGN property. ARAT is a Fokker 27 MK pressurized twin turboprop aircraft (service altitude = 5800 m, cruising speed = 350 km/h, flight endurance = 5 hr; on-board computer systems: HP1000 A900, recordings on high-capacity digital video cassette, two Exabyte 2.5 GByte recorders).

ARC . . . . . . . . . . . Ames Research Center (NASA facility at Moffett Field, CA, and at the Dryden Flight Research Facility in Edwards, CA, USA)

ARC ........... Aggregation of Red Blood Cells (Shuttle experiment) Archimedes I, II . Coordinated European airborne campaigns in the North Sea region

(start in 1983, Archimedes Ila took place in April1988) ARCS .......... Austrian Research Center Seibersdorf (since 1956, with sites at Seib

ersdorf, Leoben, Ranshofen, Vienna, Graz, Dornbirn, Wiener-Neustadt, and Budapest)

ARCSS ........ Arctic Center of System Science (at NSIDC of U. of Colorado, Boulder, CO, USA)

ARESE ........ ARM Enhanced Shortwave Experiment (campaign) ARGO ......... ''Array for Geostrophic Oceanography," a global array of buoys [an in

ternational ocean program, part of GCOS/GOOS and CLIVAR- it consists of an array of 3000 free-drifting (Lagrangian) profiling floats that measure the temperature and salinity of the upper 2000 m of the ocean; start of deployment in 2000].

ARGOS ........ Argos (CNES System) is a data collection and location system with a space segment and a ground segment. ARGOS is operational on NOAA polar-orbiting S/C. G.15.4, C.1

ARGOS ........ Advanced Research and Global Observation Satellite (DoD, M.l) ARIANESPACE A commercial launch service provider of Europe with HQ in France

(since 1980, first commercial operator of launchers in the world). Twelve European countries participate in the Ariane program.

ARIES . . . . . . . . . Australian Resource Information and Environment Satellite ARISTOTELES . Applications and Research Involving Space Thchniques Observing The

Earth's Field from Low Earth Orbiting Satellite (planned but cancelled ESA Mission)

ARM .......... Atmospheric Radiation Measurement (campaign program of DOE) ARM CAS ...... Arctic Radiation Measurements in Column Atmosphere-Surface Sys-

tem (campaign) ARNS . . . . . . . . . Aeronautical Radionavigation Service ARTEMIS ...... Advanced Relay and Technology Mission Satellite (ESA) ARPA . . . . . . . . . Advanced Research Project Agency (US) ARQ .......... Automatic-Repeat Request ASA ........... Austrian Space Agency (Vienna, since 1972) ASAP . . . . . . . . . . Adaptive Sensor Array Processing (MIT ILL) ASAP .......... Advanced Sensors Application Program (US Navy) ASAP .......... Airborne Science and Application Program (USGS, NASA)


ASAP .......... Ariane Structure for Auxiliary Payloads (ASAP provides launch opportunities for microsatellites on a commercial basis, the ASAP-5 ring structure can accommodate up to 8 microsatellites with a volume restriction of 60 em x 60 em x 80 em)

ASCOT ........ Atmospheric Studies in Complex Terrain (campaign) ASCS .......... Agricultural Stabilization and Conservation Service (USA) ASDAR . . . . . . . . Aircraft to Satellite Data Relay (wind observations are reported from

commercial aircraft at cruising altitude via meteorological satellite communication links at 7 minute intervals)

ASE ........... Automatic Air-Sampling Equipment, see P.40.4 ASEM ......... Assembly of Station by EVA Methods (Shuttle demonstration) ASES . . . . . . . . . . American Solar Energy Society ASF . . . . . . . . . . . Alaska SAR Facility in Fairbanks, Alaska (DAAC of NASA EOS Pro

gram. ASF is located at the Geophysical Institute of the University of Alaska at Fairbanks. Position: 65°N, 148°W ASF is in effect a US-PAF for ERS-1/2 data as well as for JERS-1 and RADAR SAT data.)

ASHOE ........ Airborne Southern Hemisphere Ozone Experiment (campaign) ASI ............ Agenzia Spaziale ltaliana (formerly PSN). ASI is the Italian Space

Agency, Rome (since 1988) ASI!CGS ....... ASI!Centro di Geodesia "Guiseppe Colombo" in Matera, Italy, for

Space Geodesy, Remote Sensing and Space Robotics. CGS hosts the I-PAF (Italian Processing and Archiving Facility), a multimission facility for archiving, processing and distributing remote sensing data.

ASI ............ Alcatel Space Industries, France, since 1998 (ASI represents the merger of four space hardware development divisions from Alcatel, Dassault, Thomson and Aerospatiale)

ASIC .......... Application Specific Integrated Circuit ASIM . . . . . . . . . . Application Specific Microinstrument ASP ........... Attitude Sensor Package (Shuttle payload of ESA) ASPRS . . . . . . . . . American Society for Photogrammetry and Remote Sensing (Bethes

da, MD, since 1934) ASRI . . . . . . . . . . Asher Space Research Institute (of Technion Israel Institute of

Technology, Haifa, since 1986) ASRI . . . . . . . . . . Australian Space Research Institute, Elizabeth, SA ASTEX . . . . . . . . Atlantic Stratocumulus Transition Experiment (airborne campaign at

the Azores in 1992) ASTP .......... Apollo-Soyuz Test Project (1975) ASTRE . . . . . . . . Accelerometre Spatial Triaxial Electrostatique [an ESA accelerometer

built by ONERA and part of ES~s MMA (Micro gravity Measurement Assembly) flown on Shuttle flights STS-83 and STS-94]

Astrium . . . . . . . . Astrium is the name of a new European space company, a daugther of EADS, formally created in 2000. Astrium is a merger of Aerospatiale Matra of Paris, France, DASA of Munich Germany, and Marconi Electronic Systems of Stanmore, UK. German Astrium facilities are at Bremen, Ottobrunn, Friedrichshafen, Lampoldhausen, Rostock and Trauen. The French/British MMS (Matra Marconi Space) facilities are located at Portsmouth and Stevenhage, UK, and at Toulouse and Velizy, France.

ASTRO-SPAS ... Astronomy Platform -Shuttle Pallet Satellite ASU ........... Arizona State University (Tempe, AZ) ATEx .......... Advanced Tether Experiment (NRL) ATEX . . . . . . . . . Atlantic Tropospheric Experiment (campaign) ATI ............ Along-Track Interferometry ATLAS . . . . . . . . Atmospheric Laboratory for Application and Science (NASA pro

gram, payload series on Shuttle), J.2 ATLAS ........ Autonomous Temperature Line Acquisition System (NOAA!PMEL

mooring system measuring surface wind, air temperature, SST, ten sub-


surface temperatures and two subsurface pressures; all data are monitored by ARGOS)

ATLID ......... Atmospheric Lidar (Sensor), an ESA backscatter lidar ATN ........... Advanced TIROS-N Series (NOAA, launched from 1983 on) ATS ........... Application Technology Satellite (NASA GEO satellite series prior to

GOES) ATSB .......... Astronautic Technology SB, Kuala Lumpur, Malaysia ATTAS ......... Advanced Technology Testing Aircraft System (VFW-614 of DLR) ATV ........... Roton Atmospheric Test Vehicle (of Rotary Rocket Company, Red

wood City, CA). Roton ATV is a fully reusable, single-stage-to-orbit, commercial launch vehicle. Roton is powered by a rotary engine burning liquid oxygen and jet fuel. ATV made its first successful flight on July 23, 1999.

ATV . . . . . . . . . . . Automated Transfer Vehicle (ESA cargo resupply vehicle for ISS to be launched by Ariane-5, payloads of up to 7,500 kg can be delivered)

AU ............ Astronomical Unit, Sun-Earth distance= 1.496 x 108 km (average) AURA . . . . . . . . . Association of Universities for Research in Astronomy [Washington

DC, since 1957, AURNSTSI (Space Telescope Science Institute) is the operator of the Hubble Space Telescope for NASA]

AVHRR ....... Advanced Very-High Resolution Radiometer (NOAA Sensor, AVHRR/3 on NOAA-K,L,M,N is to be renamed in VIRSR for NOAA-O,P,Q)

AVISO ......... Archivage Validation and Interpretation des donnees des Satellites Oceanographiques [Archiving, Validation and Interpretation of Satellites oceanographic data (CNES data center for GEOSAT, Topex/Poseidon, ERS-1/2, ENVISAT, Jason-1, etc.)]

AWCS ......... Automated Wafer Cartridge System (Shuttle payload) AWG .......... American Wire Gauge (the higher the number the thinner the wire) AWl ........... Alfred Wegener Institut for Polar and Marine Research, Bremerhaven

(since 1980) and Potsdam since 1992 (Germany) AWS ........... Automated Weather Station AXAF ......... Advanced X-ray Astrophysics Facility, a NASA satellite mission in a

high elliptical Earth orbit, deployed by Shuttle STS-93; in the spring of 1999 AXAF has been renamed to "Chandra X-ray Observatory" in honor of the late India-American Nobel Laureate Subrahmanyan Chandrasekhar

AZBS .......... Avionik Zentrum Braunschweig (Germany)

B BA . . . . . . . . . . . . Baroreflex (Shuttle payload on D2 mission) BAC ........... Block Adaptive Quantization (a SAR raw data compression method) BADC . . . . . . . . . British Atmospheric Data Center (at RAL, Chilton, UK) BAEX . . . . . . . . . Baltic Aerosol Experiment (campaign) BAHC ......... Biospheric Aspects ofthe Hydrological Cycle (IGBP core project since

1994) BALTEX ....... Baltic Sea Experiment (campaign) BAMS . . . . . . . . . Bulletin of the American Meteorological Society (a periodical) BAS ........... British Antarctic Survey (Cambridge, UK) BATC .......... Ball Aerospace and Technologies Corporation (Aerospace Systems Di

vision in Boulder, CO, and Telecommunication Products Division in Broomfield, CO) formerly: Ball Brothers Research Corporation, since 1956, [manufacturer of satellites such as: Seasat, SIR-C, COBE (Cosmic Background Explorer), CGRO (Compton Gamma Ray Observatory), ERBS, CRRES, GF0-1; and builder of instruments: CZCS, GHRS (Goddard High Resolution Spectrograph), STIS (Space Telescope Imaging Spectrograph), and NICMOS (Near-Infrared Camera and Multi-Object Spectrometer), all on HST, etc.]


BASE .......... Beaufort and Arctic Storm Experiment (campaign) BATERISTA . . . Biosphere-Atmosphere Transfer and Ecological Research, In situ

Studies in Amazonia (campaign) BATGE ........ Biosphere-Atmosphere Trace Gas Exchange in the Tropics (IGBP/

IGAC campaign) BATS .......... Bermuda Atlantic Time-Series Study (campaign) BB . . . . . . . . . . . . Biolabor (Shuttle D2 mission) BBXRT ........ Broad Band X-Ray Telescope (part of ASTR0-1 observatory, Shuttle) BCP . . . . . . . . . . . Ball (or BAT C) Commercial Platform (BCP 2000 series bus, BCP 4000

series, BCP 5000, etc.) BCRS .......... Netherlands Remote Sensing Board (Delft, The Netherlands) BCSC .......... Boeing Commercial Space Co. (a subsidiary of the Boeing Co, char-

tered to commercialize space technologies) BDPU ......... Bubble, Drop and Particle Unit (Shuttle experiment) BDS ........... Bioreactor Demonstration System (Shuttle payload) BEST . . . . . . . . . . Bilan Energetique du Systeme Tropical (Tropical System Energy Bud

get), a proposed CNES mission BGR .......... Bundesanstalt fiir Geowissenschaften und Rohstoffe (Hannover, Ger-

many) BIB . . . . . . . . . . . . Blocked Impurity Band (detector type) BIBEX ......... Biomass Burning Experiment (program of IGBP/IGAC) BIMDA ........ Bioserve/Instrumentation Technology Associates Materials Disper-

sion Apparatus (Shuttle payload) BiCMOS ....... Bipolar Complementary Metal-Oxide Semiconductor BIL ............ Band Interleaved by Line (image organization) BILTEN ........ TUBITAK-METU BILTEN- Information Technologies and Research

Institute of the Scientific and Technical Council of Turkey [located on the campus of the Middle East Technical University (METU), Ankara, Turkey]

BI03D ......... Biochemistry of 3-D Tissue Engineering (Shuttle Payload) BIP ............ Band Interleaved by Pixel (image organization) BIPM .......... Bureau International des Poids et Mesures (Paris) BIRA . . . . . . . . . . Belgisch Instituut voor Ruimte Aeronomie (Brussels, Belgian Institute

of Space Aeronomy) BLAST ........ Battlefield Laser Acquisition Sensor Test (Shuttle experiment) BLM .......... Bureau of Land Management (USA) BMBF . . . . . . . . . Bundesministerium fiir Bildung, Wissenschaft, Forschung und

Technologie (German Ministry of Education, Science, Research and Technology, the successor to BMFT, since 1994)

BMDO ......... Ballistic Missile Defense Organization [US, Division within DoD, formerly SDIO (Strategic Defense Initiative Organization)]

BMFT ......... Bundesministerium fiir Forschung und Technologie (German Ministry of Research and Technology, prior to 1994)

BMO .......... British Meteorological Office (same as UKMO, HQs in Bracknell, Re-mote Sensing Instrumentation branch in Farnborough)

BMRC ......... Bureau of Meteorology Research Centre (Melbourne, Australia) BMV .......... Bundesministerium fiir Verkehr (German Ministry of Transportation) BMVg ......... Bundesministerium fiir Verteidigung (German Ministry of Defense) BNL ........... Brookhaven National Laboratory (Upton, NY, USA) BNSC .......... British National Space Centre (London, UK) since 1985 BOC ........... Binary Offset Coding (modulation technique) Boeing Co ...... Seattle, WA, USA. A conglomerate (over 200,000 employees) of Boe

ing + Rockwell International (purchase of Rockwell's aerospace and defense business in Dec. 1996) + McDonnell Douglas Corp. (merger with Boeing in Aug. 1997). Boeing is also a large manufacturer of telecommunication satellites. In October 2000, The Boeing Company acquired three units within Hughes Electronics Corporation: Hughes


Space and Communications Company, Hughes Electron Dynamics, and Spectrolab, Inc., in addition to Hughes Electronics' interest in HRL (Hughes Research Laboratory). The four are now part of Boeing's newest subsidiary, Boeing Satellite Systems, Inc.

BOREAS ...... Boreal Ecosystem-Atmosphere Study (campaign) BOST . . . . . . . . . . Belgian Office of Science and Technology BPDF . . . . . . . . . . Bidirectional Polarization Distribution Function BPOT . . . . . . . . . . Bioluminescence Potential BPSK .......... Bi-Phase Shift Keying (modulation technique) BRDF ......... Bidirectional Reflectance and Distribution Function BREMSAT . . . . . University of Bremen Satellite (Shuttle payload) BRIC .......... Biological Research in Canister (Shuttle experiment) BrO . . . . . . . . . . . Bromine monoxide BSH . . . . . . . . . . . Bundesamt fiir Seeschiffahrt und Hydrographie (Hamburg, Germany) BSI . . . . . . . . . . . . British Standards Institution BSPO . . . . . . . . . . Belgian Science Policy Office BSRN ......... Baseline Surface Radiation Network (WCRP/GEWEX) BSTC . . . . . . . . . . Biotechnology Specimen Temperature Controller (Shuttle)

c CIA ............ Coarse Acquisition (a GPS and GLONASS code) CAAC . . . . . . . . . Civil Aviation Association of China CAFE ......... Central Australian Fronts Experiment (campaign) CAM .......... Centre d'Aviation Meteorologique (France) CAMAREX . . . . Carbon in the Amazon River Experiment (campaign) CAMEX ....... Convection and Atmospheric Moisture Experiment (airborne cam-

paign conducted at NASA Wallops Flight Facility, Wallops Island, VA) CAN ........... Controller Area Network (used in embedded systems) CANEX . . . . . . . . Canadian Experiments (Shuttle payload) CAO .......... Central Aerological Observatory (Moscow) CAPE ......... Convection and Precipitation Electrification Experiment (campaign) CAPL . . . . . . . . . . Capillary Pumped Loop (Shuttle experiment of Hitchhiker payload,

see also 'CPq CARIBIC ...... Civil Aircraft for Remote-Sensing and In-Situ-Measurements in Tro

posphere and Lower Stratosphere Based on the Instrumentation Container Concept (P.40.3)

CART ......... Cloud and Radiation Testbed [field measurement component of the DOE ARM program; the three CART sites are: SGP (Southern Great Plains) near Billings in northern Oklahoma, TWP (Tropical Western Pacific on Manus Island, Papua, New Guinea), and NSA (North Slope of Alaska)]

CAPTEX . . . . . . . Cross-Appalachian Tracer Experiment (campaign) CAS ........... Chinese Academy of Sciences (Beijing, China, since 1949) CAS/CSSAR . . . . CAS/Center for Space Science and Applied Research, Beijing, China CAS/IRSA . . . . . . CAS/Institute for Remote Sensing Applications, Beijing, China CAS/SITP . . . . . . CAS/Shanghai Institute of Technical Physics, Shanghai, China CASA . . . . . . . . . . Construcciones Aeronauticas S.A. (Madrid, Spain). In July 1999 CASA

merged with DASA (DaimlerChrysler Aerospace AG) CASC . . . . . . . . . . China Aerospace Science & Technology Corporation (Beijing, since

1993, also referred to as CAC). CASC, as a large state-owned enterprise, exerts primary control over the national space program on a dayto-day basis (handling of internal matters). CASC specializes in developing, building and suppling launch vehides, satellites, various types of strategic and tactical missiles as well as satellite ground application systems and providing commercial launch services. Over 130 Chinese organizations are subordinate to CASC, including five large academies [CALT (Chinese Academy of Launch-Vehicle


Technology), CAST (Chinese Academy of Space Technology), SAST (Shanghai Academy of Space-Flight Technology), CASET (Chinese Academy of Space Electronic Technology), and the Academy of Space Chemical Propulsion Technology]

CASI . . . . . . . . . . Canadian Aeronautics and Space Institute CASP . . . . . . . . . . Canadian Atlantic Storms Program (campaign) CAST .......... Center for Aerospace Technology (Weber State University, Ogden,

Utah) CAST .......... Chinese Academy of Space Technology (Beijing, China, since 1968) CATSAT . . . . . . . Cooperative Astrophysical and Technology Satellite (part of STEDI

program, see N.17.3) CBE . . . . . . . . . . . Chemical Beam Epitaxy (a growth technique) CBERS ........ China/Brazil- Earth Resources Satellite, D.7. The satellite is also re-

ferred to as Ziyuan-1, meaning 'resource' in Chinese. CCAFS ........ Cape Canaveral Air Force Station (Cape Canaveral, FL, USA) CCD ........... Charge-Coupled Device (solid-state detector type) CCE ........... Charge Composition Explorer (SIC of AMPTE mission, K.4.3) CCIR .......... Comite Consultatif International des Radiocommunications (Interna

tional Consultative Committee for Radio Communications , an organ of ITU). As of 1990 CCIR was renamed to ITU-R.

CCITT . . . . . . . . . Comite Consultatif International Te!ephonique et Telegraphique (one of three bodies for the definition of OS I. CCITT is a permanent organ of ITU). As of 1990 CCITT was renamed to ITU-T (ITU-Telecommunications)

CCM-A ........ Cell Culture Module-A (Shuttle experiment) CCN ........... Cloud Condensation Nuclei CCPD . . . . . . . . . Charge-Coupled Photo Detector CCRS .......... Canada Center for Remote Sensing (Ottawa, Ontario; established in

1972, part of 'Department of Energy, Mines and Resources,' Canada) CCSDS . . . . . . . . Consultative Committee for Space Data Systems CD ............ Compact Disk (introduction in 1982) CDA ........... Command and Data Acquisition (NOAA Antenna, downlink concept) CDDIS ........ Crustal Dynamics Data Information System (database at GSFC) CDGPS . . . . . . . . Carrier -phase Differential GPS (a relative position measurement tech-

nique) CDMA ......... Code Division Multiple Access (a communication access scheme) CDP ........... Crustal Dynamics Program (NASA) CdZnTe ........ Cadmium Zinc Telluride (a detector material- also referred to as CZT) CD-ROM . . . . . . Compact Disk- Read Only Memory (storage capacity up to 650 MByte) CD-R/W ....... Compact Disk- Read/Write CDTI . . . . . . . . . . Center for Technological and Industrial Development, Madrid, Spain CDWL ......... Coherent-detection Doppler Wind Lidar CEA . . . . . . . . . . . Commissariat a l'Energie Atomique CEAREX ...... Coordinated Eastern Arctic Experiment (campaign) CEBAS . . . . . . . . Closed Equilibrated Biological Aquatic System (Shuttle payload) CEC . . . . . . . . . . . Commission of the European Communities (Brussels, Belgium) CEES .......... Committee on Earth and Environmental Sciences (US interagency

committee) CEMAGREF ... Centre d'Etude du Machinisme Agricole du Genie Rural et des Eaux et

Forests (France) CEOS . . . . . . . . . Committee on Earth Observation Satellites CEPEX ........ Central Equatorial Pacific Experiment (campaign) CEPT .......... European Conference of Postal and Telecommunications Administra

tions (Montreux, Switzerland, since 1959). CEPT comprises 43 European countries and is charged with representing Europe on such items as spectrum issues, etc.


CERFACS ...... Centre Europeen de Recherche et de Formation Avancee en Calcul Scientifique (Toulouse, France, since 1987) European Center for Research and Advanced Training in Scientific Computation

CERGA ........ Centre d'Etudes et des Recherches en Geodynamique et Astrometrie (in Grasse, France)

CERISE ....... Caracterisation de l'Environnement Radioelectrique par un Instrument Spatial Embarque, (French S/C), D.40.11

CERN ......... Centre Europeen de Recherche Nucleaire (Geneva, Switzerland) CES . . . . . . . . . . . Committee on Earth Studies -a standing committee ofthe Space Stud-

ies Board within the National Research Council (NRC), USA CESAR ........ Cooperacion Espanola-Argentina (satellite of INTA and CONAE) CESBIO ....... Centre d'Etudes Spatiales de Ia Biosphere (Toulouse, France) CESR .......... Centre d'Etude Spatiale des Rayonnements (Toulouse, France, part of

CNRS) CETA .......... Crew and Equipment Translation Aids (Shuttle experiment) CETP .......... Centre d'etude des Environnements Terrestre et Planetaire (Velizy/

Saint-Maur, France, CNRS Lab) CEU ........... Commission of the European Union (successor of previous CEC) CEV ........... Centre d'Essais en Vol (French Test Flight Center) CfAO .......... Center for Adaptive Optics, UCSC (University of California at Santa

Cruz) CFCs . . . . . . . . . . Chlorofluorocarbons CFC-11 . . . . . . . . CCI3F, trichlorofluoromethane, Freon-11 CFC-12 ........ CC12F2, dichlorodifluoromethane, Freon-12 CFES .......... Continuous Flow Electrophoresis System (Shuttle payload) CFRP . . . . . . . . . . Carbon Fiber Reinforced Plastic (also: CFRM for Material) CGBA ......... Commercial Generic Bioprocessing Apparatus (Shuttle experiment) CGWIC ........ China Great Wall Industry Corporation (Beijing, since 1980), provider

of Long March launch services to the world market CGMS ......... Coordination Group for Meteorological Satellites [since 1972; active

CGMS members are: EUMETSAT (Europe), JMA (Japan), China, Russia, NOAA (USA), WMO]. The global network of meteorological satellites constitutes a major portion of the space-based GOS (Global Observing System) of WWW (World Weather Watch).

CGP ........... Shuttle payload consisting of: [CSE (Cryo System Experiment), GP (Glow Phenomenon)]

CGWIC ........ China Great Wall Industry Corporation (launch service provider) CH3Cl . . . . . . . . . Methyl chloride CH4 . . . . . . . . . . . Methane CHAMP . . . . . . . Challenging Minisatellite Payload (E.1) CHAMP ....... Comet Halley Active Monitoring Program (Shuttle experiment) CHASE ........ Coronal Helium Abundance Spacelab Experiment (Spacelab-2) CHEOPS ....... CHEmistry of Ozone in the Polar Stratosphere (airborne campaign) CHORUS ...... Chemistry of Ozone Reduction in the Lower Stratosphere (first Stra-

to-2C mission) CHROMEX .... Chromosomes and Plant Cell Division (Shuttle experiment) CHRPT . . . . . . . . Chinese High Resolution Picture Transmission (downlink mode) CID ........... Charge-Injection Device (a charge-tranfer detection technology) CID ........... Collision-Induced Dissociation (a measurement technique in the at

mospheric sciences for studies of ion-molecule reactions, etc.) CIDESON ...... Centro de lnvestigacion y Desarrollo de los Recursos Naturales de So

nora (Hermosillo, Mexico) CIEMAT ....... Centro de Investigaciones Energeticas y Medioambientales (Environ

mental and Energetic Research Center), Spain CIESIN ........ Consortium for International Earth Science Information Network (a

private nonprofit corporation in Ann Arbor, Michigan (University Center). CIESIN serves scientific, policy-making, educational, and


public access data and information needs. CIESIN developed and is operating SEDAC (Socio-Economic Data and Applications Center) as part of one of nine data centers of EOSDIS.

CIGNET ....... Cooperative International GPS Network of lAG (International Association of Geodesy), H.4.3.6

CIGS .......... Copper Indium Gallium Diselenide (solar arrays based on thin film technology)

CIMS . . . . . . . . . . Chemical Ionization Mass Spectrometry (a measurement technique frequently used for atmospheric measurements)

CIMSS . . . . . . . . . Cooperative Institute for Meteorological Satellite Studies (University of Wisconsin, Madison)

CINDE ........ Convection Initiation and Downburst Experiment (campaign) CIR ........... Color Infrared (video images) CIRA . . . . . . . . . . Centro Italiano Ricerche Aerospaziali (Italian Aerospace Research

Center) since 1984, Capua, Italy CIRAC . . . . . . . . Canadian Institute for Research in Atmospheric Chemistry CIRES ......... Cooperative Institute for Research in Environmental Sciences (Uni

versity of Boulder, and at NOAA, Boulder, CO, USA) CIS ............ Commonwealth oflndependent States (part of former Soviet Union or

USSR) CIT ............ California Institute of Technology (Pasadena, CA) CIT . . . . . . . . . . . . Computerized Ionospheric Tomography CITE .......... Chemical Instrumentation Test and Evaluation (campaign) CIV ........... Critical Ionization Velocity (Shuttle experiment) CIVEX ........ Cloud Instruments Validation Experiment (campaign) CLARA . . . . . . . . Cloud And Radiation (campaign) CLASS ......... Cross-chain LORAN Atmospheric Sounding System (NCAR ground-

based sounding stations) CLEOPATRA ... Cloud Experiment Oberpfaffenhofen and Transports (campaign) CLIVAR ....... Climate Variability and Predictability (WCRP campaign program) CLIVAR-ACC .. CLIVAR- Anthropogenic Climate Change CLIVAR-DecCen CLIVAR- Decadal-to-Centennial time-scales CLIVAR-GOALS CLIVAR- Global Ocean-Atmosphere-Land System CLOUDS Cloud and Radiation Monitoring Satellite (a proposed ESA mission as

of 2001, A.7) CLOUDS Cloud Logic to Optimize Use of Defense Systems (Shuttle payload) CLUSTER ..... ESAJNASA Solar-Terrestrial Mission (K.7) ClO ........... Chlorine monoxide ClON02 ....... (ClON03) Chlorine nitrate CLS ........... Collecte, Localisation, Satellites (with HQ in Toulouse, France) CLS

was set up in 1986 to market the Argos (data collection) system. C-MAN ........ Coastal-Marine Automated Network [NOAAJNWS/NDBC moored

buoy network (over 100 buoys) with hourly reports via GOES DCS] CMA .......... China Meteorological Administration, Beijing (government agency) CMAJNSMC .... CMA/National Satellite Meteorological Center, Beijing, China CMC .......... Canadian Meteorological Centre CME . . . . . . . . . . Coronal Mass Ejection (of the sun) CMESS-95 ..... Cooperative Multiscale Experiment Spring/Summer 1995 (campaign) CMIX . . . . . . . . . Commercial Materials Dispersion Apparatus Instrument Technology

Associates Experiments (Shuttle experiment) CMOS ......... Complementary Metal-Oxide Semiconductor (solid-state micropro-

cessor technology) CMS . . . . . . . . . . . Centre de Meteorologie Spatiale (Lannion, France) CMT . . . . . . . . . . CdHgTe (detector type) CN . . . . . . . . . . . . Condensation Nuclei CNCR ......... Characterization of Neurospora Circadian Rhythms (Shuttle payload)


CNES .......... Centre National D'Etudes Spatiales (Space Agency of France, Paris, Toulouse, Evry, and Kourou, since 1962). Employment (1999) of 2500 scientists and engineers; of these, about 1700 employees are at Toulouse. CNES/HQ is in Paris with about 250 employees.

CNES/AVISO ... CNES/Archiving, Validation and Interpretation of Satellites oceanographic data (CNES data center for GEOSAT, Topex/Poseidon, ERS-1/2, ENVISAT, Jason-1, etc.)

CNET ......... Centre National d'Etudes des Telecommunications (France Telecom) CNIE .......... Comision Nacional de Investigaciones Espaciales (former Space

Agency of Argentina) CNR ........... Consiglio Nazionale delle Ricerche (National Research Counsil of Ita

ly, Rome). CNR is a government agency which promotes and coordinates institutional research in the interests of Italy. CNR was founded in 1923 and reorganized in 1945 and 1979. CNR funds/maintains 157 institutes, 117 study centers, and 16 research groups throughout Italy. Research is supported in the natural and human sciences. In 1980 PSN (National Space Program) was created within CNR. Some space projects supported by CNR are: Italsat, TSS (Tethered Satellite System), Iris (propulsion system for the transfer of useful loads from the Space Shuttle's "hold" to a higher orbit), Lageos-2, and Sax (X-ray astronomy). CNR maintains a number of cooperations with various space agencies. In 1988 ASI (Agenzia Spaziale Italiana) was founded which succeeded CNR in relations concerning matters of planning and administrative nature. Nevertheless, CNR continues to follow specific aspects of research within the context of its own bodies.

CNR/DCAS .... CNR I Direzione Centrale Attivita Scientifiche (Rome, Italy) CNR/FISBAT . . . CNR I Istituto per lo Studio dei Fenomeni Fisici e Chimici della Bassa

ed Alta Atmosfera (Institute of Physics and Chemistry of the Lower and Upper Atmosphere, Bologna, Italy)

CNR/IFA ....... CNR I Istituto di Fisica dell' Asmosfera (Institute for the Physics of the Atmosphere, Frascati, Italy)

CNR/IFAM ..... CNR I Istituto di Fisica Atomica e Molecolare (Pisa, Italy) CNR/IFCTR . . . . CNR I Istituto die Fisica Cosmica e Teccnologie Relative (Milano) CNR/IFSI ...... CNR I Istituto de Fisica dello Spazio Interplanetario (Frascati, Italy) CNR/IROE ..... CNR I Istituto di Richerca sulle Onde Elettromagnetiche (Florence,

Italy) CNR/IMGA .... CNR I Istituto per lo Studio delle Metodologie Geofisiche Ambientali

(Bologna, Italy) CNRIITRE . . . . . CNR I Istituto di Technologie e Studie della Radiazioni Extraterrestri

(Bologna, Italy) CNR/LARA . . . . CNR I Laboratorio Aereo per Ricerche Ambientali (Laboratory for

Airborne Environmental Studies, Rome, Italy) CNR/PSN ...... Consiglio Nazionale delle Ricerche I Piano Spaziale Nationale (Italy) CNRM ......... Centre National des Recherches Meteorologiques (France) CNRS ......... Centre National de Ia Recherche Scientifique (National Research Cen

ter of France). CNRS is a government -funded basic-research organization which employs about 26,000 people, including more than 11,000 research scientists. The agency maintains facilities throughout France. There are over 1500 CNRS laboratories active in all fields of science. Most CNRS laboratories rely for their research on partnerships with French universities. There are also many CNRS cooperations and exchanges with other research organizations on a national and internationallevel as well as with French industry. Only a few facilities (dealing mostly with the sciences of the universe, such as: oceanography, geophysics, climatology, hydrology, volcanology, seismology, astronomy, astrophysics, etc.) are listed below.

CNRS/CESR . . . CNRS/Centre d'Etude Spatiale des Rayonnements (Toulouse, France)


CNRS/CERGA CNRS/Centre d'Etudes et des Recherches en Geodynamique et Astrometrie (Grasse, France)

CNRS/CETP . . . . CNRS/Centre d'Etude des Environnenments Terrestre et Planetaires, (sites at: Velizy, Issy-les-Moulineaux, and Saint-Maur des Fosses, France)

CNRS/IAS ...... CNRS/Institut d'Astrophysique Spatiale (Orsay, France) CNRS/INSU .... CNRS/Institut National des Sciences de l'Univers (Paris, France) CNRS!LAS ..... CNRS/Laboratoire d'Astronomie Spatiale (Marseille, France) CNRS/LMD . . . . CNRS/Laboratoire de Meteorologie Dynamique (Palaiseau, France) CNRS!LOA ..... CNRS!Laboratoire d'Optique Atmospherique (University of Lille,

France) CNRS!LPCA ... CNRS!Laboratoire de Physique et Chimie de !'Atmosphere (Universi-

ty of Strasbourg, France) CNRS!LPCE .... CNRS/Laboratoire de Physique et de Chimie de l'Environnement (Or

CNRS/SA ..... . CNRSC ....... . CNSA ........ .

leans-la-Source, France) CNRS/Service d'Aeronomie (Verrieres-le-Buisson, France) China National Remote Sensing Center (since 1981) China National Space Administration (Beijing, since 1993). The principal role of CNSA is to serve as China's policy organization and interface with other national space agencies.

CNS/ATM ...... Communication, Navigation and Surveillance/Air Traffic Manage

CNTS ......... .

co············ C02 .......... . COARE ....... .

COAST ....... . CODAG CODAR ...... .

ment) Centre National des Techniques Spatiales (Algiers, Algeria) Carbon monoxide Carbon dioxide Coupled Ocean Atmosphere Response Experiment (campaign, see TOGNCOARE) Coastal Oxidant Assessment for Southeast Texas (campaign) Cosmic Dust Aggregation (Shuttle payload) Coastal Ocean Dynamic Application Radar (a ground-based, over-thehorizon radar which reflects off of the ionosphere to measure sea sur-face roughness and currents)

CODE ......... Coastal Ocean Dynamics Experiment (campaign) COF ........... Columbus Orbital Facility (ESA module on ISS) COHMEX ..... Cooperative Huntsville Meteorological Experiment (campaign) COMETS ...... Communications and Broadcasting Engineering Test Satellite (proto

type data relay satellite of Japan) CONAE ....... Comisi6n Nacional de Actividades Espaciales, Buenos Aires, Argenti

na (National Commission on Space Activities, since 1992) - Space Agency of Argentina

CONCAP ...... Consortium for Materials Development in Space Complex Autono-mous Payload (Shuttle experiment)

CONUS ........ Continental United States ('lower 48 states') COPE ......... Coastal Ocean Probing Experiment (campaign) COPS-91 ....... Cooperative Oklahoma Profiler Study-1991 (campaign) CO RON AS . . . . . Complex of Orbital Observations of the Activity of the Sun (Satellite of

the Russian Space Agency, K.8) COSMIC ....... Constellation Observing System for Meteorology, Ionosphere and Cli

mate (A.24) COSMOS ...... The term 'Cosmos' or 'Kosmos' is used in Russia to designate any of a

series of unmanned satellites that were launched starting in 1962 with Cosmos-1 (the counting in 1988 was up to 1800, in 1993 it is around 2200). The Cosmos satellite series has been used for a wide variety of purposes, including scientific research, Earth observation, experimental/technological payloads, preoperational meteorological satellites, navigation satellites, etc. There are also many satellites with military payloads under the Cosmos designation.


'Cosmos' is also the name of a Russian launch vehicle (first launch in 1964, from 1970-'87 there were 371 successful flights of the Cosmos launcher). The Cosmos launch vehicle remains in service (1996).

COSPAR ....... Committee on Space Research (of ICSU, since 1958). COSPAR is an interdisciplinary scientific organization concerned with international progress in all areas of scientific research carried out with space vehicles, rockets, and balloons.

COSPAS Space System for the Search of Distressed Vessels (Russia's equipment flown on polar-orbiting S/C).

COSSA ........ CSIRO Office of Space Science and Applications (since 1984, Canberra, Australia)

COTES . . . . . . . . Conventional Terrestrial Reference System (an IERS pro~ram for the specifications of positions on or near the Earth's surface) 108)

COTS .......... Commercial-Off-The-Shelf (products) CPCG ......... Commercial Protein Crystal Growth (Shuttle experiment) CPFSK ......... Continuous Phase Frequency Shift Keying (a modulation method) CPL . . . . . . . . . . . Capillary Pumped Loop Experiment (Shuttle) CPMA ......... Code Position Multiple Access (communication access concept) CPR ........... Cloud Profiling Radar (GEWEX) CPRA . . . . . . . . . Control of the Reception Pattern multi-element Antenna CRA ........... Centro Ricerche Aerospaziali (University of Rome, Italy) C-RAM ........ Chalcogenide- Random Access Memory CRC . . . . . . . . . . . Communication Research Center (an institute oflndustry Canada, lo

cated at Shirleys Bay, west of Ottawa) CRCSS ......... Cooperative Research Center for Satellite Systems (Canberra, Austra

lia, the new Australian space agency, as of Jan. 1, 1998 - it is also referred to as simply "CRC"). CRCSS, under the Cooperative Research Centres Program of the Commonwealth of Australia, is a union of 12 Australian organizations, including government, university and industry. Some of the participants are: CSIRO, University of South Australia, Queensland University of Technology, University of Newcastle, University of Technology, Sydney, Auspace Ltd. of Mitchell, ACT [Note: since 1990, Auspace has been a subsidiary ofMMS (Matra Marconi Space) of France]

CREAM ....... Cosmic Ray Effects and Activation Monitor (Shuttle payload) CREST ........ Center for Research in Earth and Space Technology (North York, On

tario, Canada). Formerly known as ISTS (Institute of Space and Terrestrial Science)

CRI ........... Crown Research Institute (New Zealand) CRISP ......... Center for Remote Imaging, Sensing and Processing (since 1992, Na

tional University of Singapore, Singapore) CRL . . . . . . . . . . . Communications Research Laboratory, Tokyo, a division of the Minis

try of Posts and Telecommunications (MPT) of Japan. Note: the former name of CRL (until1987) was RRL (Radio Research Laboratories)

CRO .......... Chemical Release Observation (Shuttle experiment) CRP . . . . . . . . . . . Cloud Radiation Program CRPE . . . . . . . . . Centre de Recherches en Physique de l'Environnement Terrestre et

Planetaire, at the following sites: Velizy, Issy-les Moulineaux, and Saint-Maur-des-Fosses, France (Lab was part of CNRS and of CNET, starting in January 1994 CRPE was reorganized and renamed CETP, there is no more dependence on CNET)

CRPSM . . . . . . . . Centro di Ricerca Progetto San Marco (San Marco ground receiving station and processing/archiving facilities located at Malindi, Kenya), CRPSM is owned and operated by the University of Rome, Italy

2108) See: "The International Earth Rotation Service," in 'The Interdisciplinary Role of Space Geodesy,' Springer Verlag, 1989, pp. 229-232


CRREL . . . . . . . . Cold Regions Research and Engineering Laboratory (US Army research facility in Hanover, NH, USA)

CRRES ........ Combined Release and Radiation Effects Satellite (All) CRSS . . . . . . . . . . Commercial Remote Sensing System (B.6); the S/C was renamed to

IKON OS CRSS .......... Canadian Remote Sensing Society (since 1973); CRSS is part of CASI

(Canadian Aeronautics and Space Institute) CRT . . . . . . . . . . . Cathode Ray Tube CRTS . . . . . . . . . . Centre Royal Teledetection Spatiales, Rabat, Marrocco CRY ........... Crew Return Vehicle (or X-38 CRY of NASA, used for ISS evacuation

in case of an emergency) CRYOFD ...... Cryogenic Flexible Diode (Shuttle payload) CRYOHP ...... Cryogenic Heat Pipe Experiment (Shuttle payload) CRYOTSU ..... Cryogenic Thermal Storage Unit (Shuttle payload) CRYSYS ....... Use of the Cryospheric System to Monitor Global Change in Canada

(campaign program) CSA ........... Canadian Space Agency (since 1989; CSA HQs and control center at

Saint-Hubert, Quebec) CSCE . . . . . . . . . . Commercial Space Centerfor Engineering (established under contract

with NASNJSC, located on the Texas A&M University campus; CSCE supports industry development of palletized commercial payloads on external platforms on ISS)

CSE ........... Consortium for Superconducting Electronics (USA) involving Bell Labs, IBM, MIT, MIT ILL, etc.

CSEM . . . . . . . . . Centre Suisse d'Electronique et de Microtechnique (or: Swiss Center for Electronics and Microtechnology), Neuchatel, Switzerland

CSER . . . . . . . . . . Center for Satellite Engineering Research (University of Surrey, UK) CSGC ......... Colorado Space Grant Consortium- a NASA-funded institution which

supports student-designed satellites CSIC .......... Consejo Superior de Investigaciones Cientificas (Spanish Research

Council, Madrid) CSIR . . . . . . . . . . Council for Scientific and Industrial Research, Pretoria, South Africa.

CSIR is Africa's largest scientific and technological research, development and implementation organization.

CSIRO ......... Commonwealth Science and Industrial Research Organization (Canberra, Australia)

CSMNCD ..... Carrier Sense Multiple Access I Collision Detection (commercially known under Ethernet)

CSMT ......... Center for Space Microelectronics Technology (NASNJPL facility, since 1987)

CSOC . . . . . . . . . Consolidated Space Operations Contract (NASA/Lockheed Martin contract for Shuttle operations, etc.). The objective is to achieve a lowrisk, commercially-based space operations program for Shuttle.

CSR ........... Centro de Sensores Remote (Italy) CSSR . . . . . . . . . . Chinese Society of Space Research CST ........... CORE Software Technology, Pasadena, CA [developer of the world's

first commercial on-line geo-spatial (image, cartographic, & demographic) indexing and distribution system]

CSTG . . . . . . . . . . Commission on International Coordination of Space Techniques for Geodesy and Geodynamics (since 1979), (Commission VIII of the International Association of Geodesy)

CSU ........... Colorado State University, Fort Collins, CO CIA ........... Canadian Target Assembly (Shuttle payload) CIA ........... Centro Tecnico Aerospacial (Sao Jose dos Campos, S.P., Brazil) CTA ........... CTA Space Systems, McLean, VA, (since 1979) manufacturer of small

satellite systems (Clark, EarlyBird, REX, etc.) and instruments; CTAST (CTA Space and Telecommunications) is the parent company


of CTA Space Systems. Note: CTA Space Systems was acquired by OSC of Dulles, VA, in Aug. 1997

CTD . . . . . . . . . . . Conductivity-Temperature-Depth profilers (a buoy type used in anumber of campaigns like NORSEX, TOGNCOARE, etc.)

CTIV .......... Processing Center for VEGETATION Imagery (operated by Vito in Mol, Belgium, VEGETATION is a SPOT-4, 5 instrument

CTP . . . . . . . . . . . Cloud Top Pressure CUE ........... Collaborative Ukrainian Experiment (Shuttle experiment) CUZK . . . . . . . . . Czech office for Surveying, Mapping and Cadastre CVF ........... Circular Variable Filter (filter technology) CVTE . . . . . . . . . Chemical Vapor Transport Experiment (Shuttle payload) CVX . . . . . . . . . . . Critical Viscosity of Xenon (Shuttle payload) CW . . . . . . . . . . . . Continuous Wave CZT . . . . . . . . . . . Cadmium Zinc Telluride (a detector material - also referred to as

CdZnTe)

D DAAC ......... Distributed Active Archive Center (NASA EOSDIS Program) DAB . . . . . . . . . . . Digital Audio Broadcasting DARA ......... Deutsche Agentur fiir Raumfahrtangelegenheiten, Bonn (German

space agency (from 1989 to Sept. 30, 1997, DARA was integrated into DLR effective Oct. 1, 1997)

DARPA . . . . . . . . Defense Advanced Research Projects Agency (US DoD agency, since 1958, DARPA started as ARPA with an early focus on space research). Technological innovations such as the Transit navigation system, Internet (in 1969 ARPANET started which become later Internet), stealth technology, and many activities in the space program were sponsored by DARPA.

DASA ......... DaimlerChrysler Aerospace AG, Munich (HQ), Germany (with 45,000 employees;. Prior to Nov. 1998, DASA stood for 'Daimler-Benz Aerospace AG. Prior to January 1995 the meaning of the acronym DASA was 'Deutsche Aerospace AG.' DASNDSS (Domier Satellitensysteme GmbH) is a DASA business unit responsible for all satellite-related activities with facilities in Friedrichshafen and Ottobrunn. DASA (founded in 1989) is a conglomerate of the previous companies: Dornier, MBB (Messerschmitt-Bolkow-Blohm), MTU (Motoren- und Turbinen-Union), and TST (Telefunken Systemtechnik). - In addition, DASA is a partner in many alliances such as: Airbus, Ariane, Eurocopter, etc. Today, the three independent business entities of DASA are: DASNAirbus, DASNDSS, and DASNMTU. -As of 2000, DASA is called Astrium GmbH (see Astrium)

DAT ........... Digital Audio Tape (a high-volume data recording technique, helical scan tape storage)

DATA-CHASER Distribution and Automation Technology Advancement - Colorado Hitchhiker and Student Experiment of Solar Radiation (Shuttle)

DBMS ......... Database Management System DBS ........... Direct Broadcasting Satellite DBSI .......... Direct Broadcasting Satellite Industries Inc. of Mill Valley, CA DC . . . . . . . . . . . . Direct Current DCRS ......... Danish Center for Remote Sensing (at EMI of TUD, Lyngby, Den

mark) DCRS . . . . . . . . . Digital Cassette Recorder System DCP ........... Data Collection Platform (ground segment platform for environmen

tal data measurement, Meteosat, GOES, GMS) DCPI .......... Data Collection Platform Interrogation (GOES) DCS ........... Data Collection System (NOAA- GOES series, Meteosat series, GMS

series, geostationary satellites).


DCT . . . . . . . . . . . Discrete Cosine Transformation (compression technique) DCW .......... Digital Chart of the World (a vector map database by DMA, Fairfax,

VA, USA) DEBITS ....... Deposition of Biogeochemically Important Trace Species DECAFE ...... Dynamics and Chemistry of the Atmosphere in Equatorial Forest

(campaign) DEE ........... Dexterous End Effector (Shuttle) DEM .......... Digital Elevation Model (also referred to as DTM = Digital Terrain

Model) DEOS ......... Delft Institute for Earth-Oriented Space Research [at Delft University

of Technology (DUT), Delft, The Netherlands] DERA ......... Defence Evaluation and Research Agency [Farnborough, UK, an

agency of MoD (Ministry of Defense)]. DERA was established in April 1995 from elements of the former RAE (Royal Aerospace Establishment).

DESPA ........ Department de Recherche Spatiale de ~Oservatoire de Paris/Meudon (France)

DFD ........... Deutsches Fernerkundungsdatenzentrum (German Remote Sensing Data Center, DLR, Oberpfaffenhofen)

DFG ........... Deutsche Forschungsgemeinschaft (German National Research Council)

DFN ........... Deutsches Forschungsnetz DFVLR ........ Deutsche Forschungs- und Versuchsanstalt fiir Luft- und Raumfahrt

(predecessor name of DLR from 1969 until 1989). History: In 1969 (April1) a merger of the following German research facilities occurred, resulting in DFVLR with HQ in Koln-Porz: AVA (Aerodynamische Versuchsanstalt, founded 1907 in Gottingen), DFL (Deutsche Forschungsanstalt fiir Luftfahrt, founded 1936 in Braunschweig), DVL (Deutsche Versuchsanstalt fiir Luftfahrt, founded 1912 in Berlin-Adlershof, after WW-11 in Miihlheim-Ruhr, since the 1960s in Koln-Porz). FFO (Flugfunkforschungsinstitut Oberpfaffenhofen), founded in 1937, was integrated into DVL(Koln-Porz) in 1965. FFM (Flugwissenschaftliche Forschungsanstalt Miinchen) joined DVL in 1963.

DGASP ........ Dye 3 Gas and Aerosol Sampling Program (IGBP!IGAC program) DGFI .......... Deutsches Geodatisches Forschungsinstitut (Munich, Germany) DGGTN ....... Direction General de Geografica del Territorio Nacional (Mexico) DGLR ......... Deutsche Gesellschaft fiir Luft- und Raumfahrt- Lilienthal-Oberth e.

V., Bonn DGON ......... Deutsche Gesellschaft fiir Ortung und Navigation (Dusseldorf, Ger-

many- German Institute of Navigation) DGPF ......... Deutsche Gesellschaft fiir Photogrammetrie und Fernerkundung DGPS ......... Differential GPS, H.4.4 DHI ........... Deutsches Hydrographisches Institut (Hamburg, Germany) DIAL . . . . . . . . . . Differential Absorption Lidar (lidar technique) DIN ........... Deutsches Institut fiir Normung (German Institute for Standardiza

tion) Discoverer II .... A US (military) technology demonstration program of DARPA, USAF

and NRO, started in 1998, with the objective to develop a high-resolution interferometric SAR system (IFSAR) for surveillance and reconnaissance

DISCOS ....... Database and Information System Characterizing Objects in Space (ESA!ESOC database for space debris and meteoroids, since 1990)

DLR ........... Deutsches Zentrum fiir Luft- und Raumfahrt e.V. (German Aerospace Center, with HQ in Koln; DLR is also the German Space Agency). On Oct.l, 1997 DARA was re-integrated into DLR. Prior to Oct.1.1997 the meaning of DLR was: Deutsche Forschungsanstalt fiir Luft- und Raumfahrt e.V.


DLR/DFD ...... DLR/Deutsches Fernerkundungsdatenzentrum (German Remote Sensing Data Center), Oberpfaffenhofen and Neustrelitz

DLR/FB ....... DLR/Flugbereitschaft (aircraft operations; FB provides the services of flying sensors for other institutes of DLR)

DLR/GSOC .... DLR/German Space Operations Center, Oberpfaffenhofen DLR/IOE ...... DLR/Institut fiir Optoelektronik (Institute of Optoelectronics),

Oberpfaffenhofen DLR/IPA ....... DLR/Institut Physik der Atmosphiire (Institute of Atmospheric

Physics), Oberpfaffenhofen DLR/IRF ...... DLR/Institut fiir Hochfrequenztechnik (Institute of Radio Frequency

Technology, Oberpfaffenhofen) DLR/IRM ...... DLR/ Institut fiir Robotik und Mechatronik (Institute of Robotics and

Mechatronics ), Oberpfaffenhofen DLR/ISST ...... DLR/Institut fiir Weltraumsensorik (Institute of Space Sensor Tech

nology and Planetary Exploration, Berlin-Adlershof). There is also the abbreviation: DLR/IWS

DLR/MUSC .... DLR/Microgravity User Support Center (Cologne, Germany) DMA .......... Defense Mapping Agency (Fairfax, VA, USA, mapping, charting &

geodetic products & services to the military, since 1972 - since 1996 DMA is an integral part of NIMA)

DMC .......... Disaster Monitoring Constellation (a 5 SIC constellation under construction by SSTL, UK, planned launch in 2002)

DMI ........... Danmarks Meteorologiske Institut (Danish Meteorological Institute, founded in 1872) Copenhagen, Denmark

DMN .......... Direction de Ia Meteorologie National (France) DMOS ......... Diffusive Mixing of Organic Solutions (Shuttle payload) DMS .......... Dimethylsulphide DMSP ......... Defense Meteorological Satellite Program (USA), G.l Dnepr . . . . . . . . . Russian/Ukrainian launch vehicle for satellites. As part of a nuclear dis

armament agreement, former Soviet SS-18 ICBMs (Intercontinental Ballistic Missiles), were renamed to Dnepr. They are either being used for commercial launches, or destroyed by Dec. 31, 2007

DOAS . . . . . . . . . Differential Optical Absorption Spectroscopy DOC .......... Department of Commerce (USA) DoD ........... Department of Defense (USA) DOE .......... Department of Energy (USA). Some major laboratories of DOE are:

ANL (Argonne National Laboratory), Argonne IL BNL (Brookhaven National Laboratory), Upton, NY FNAL (Fermi National Accelerator Laboratory), Batavia, IL LANL (Los Alamos National Laboratory), Los Alamos, NM LBL (Lawrence Berkeley Laboratory), Berkeley, CA LLNL (Lawrence Livermore National Laboratory), Livermore, CA ORNL (Oak Ridge National Laboratory), Oak Ridge, TN (since 1948) PNL (Pacific Northwest Laboratory), Richland, WA SLAC (Stanford Linear Accelerator Center), Stanford, CA SNL (Sandia National Laboratory), Albuquerque, NM and Livermore, CA

DODGE ....... Department of Defense Gravity Experiment (M.4) DOM .......... Dissolved Organic Matter DORIS ........ Determination Orbite Radiopositionnement Integres Satellite (CNES

one-way tracking system for the measurement of precision orbits); another name convention is: Doppler Orbitography and Radiopositioning Integrated by Satellite, E.21.1

DoT ........... Department of Transportation (USA) DPCM ......... Differential Pulse Code Mudulation (compression technique) DRA .......... Defence Research Agency [Malvern, Farnborough, etc., UK, with over

6000 employees; DRA was established in 1991, it is the successor orga-


nization of RAE (Royal Aerospace Establishment), ARE (Admiralty Research Establishment), RARDE (Royal Armament Research & Development Establishment), and RSRE (Royal Signal and Radar Establishment)]. As of April1995 DRA was regrouped again and integrated as a division into DERA (Defense Evaluation and Research Agency). Another DERA reorganization in April1997 dissolved DRA altogether.

DRAM ........ Dynamic Random Access Method Draper Lab . . . . . Charles Stark Draper Laboratory Inc. of Cambridge, MA. An MIT lab

founded in the 1930s; an independent non-profit research lab since 1973. Focus on GN&C (Guidance, Navigation & Control) technologies.

DRB .......... Defense Research Board, Canada DREO ......... Defense Research Establishment, Ottawa, Canada DRI ........... Desert Research Institute (of the University of Nevada) DRS ........... Data Relay Satellite (ESA system to relay information from the Euro-

pean space plane) DRTS .......... Data Relay Technology Satellite (Japan, Ka-band transmission) DSB . . . . . . . . . . . Double Sideband DSN ........... Deep Space Network (NASNJPL) DSP . . . . . . . . . . . Defense Support Program (USA, DoD SIC series in GEO using in

frared sensors to detect missile plumes against the Earth's background, to detect and report missile launches, space launches, and nuclear detonations) DSP SIC operate since the 1970s.

DSP ........... Digital Signal Processing (computer, technology) DSRI .......... Danish Space Research Institute (Lyngby, Copenhagen, Denmark) DSS . . . . . . . . . . . Dornier Satellitensysteme GmbH (of DASA, Germany) DSS ........... Delft Sensor Systems (provider of optoelectronic instruments). DSS

has been created by the integration of OIP (Optronic Instruments & Products), located in Oudenaarde, Belgium- and DIEO (Delft Instruments Electro-Optics, located in the Netherlands

DSSP . . . . . . . . . . Danish Small Satellite Program DSSS . . . . . . . . . . Direct Sequence Spread Spectrum (communication technique) DTE . . . . . . . . . . . Digital Terrain Elevation DTM .......... Digital Terrain Model (also referred to as DEM = Digital Elevation

Model) DTU .......... Technical University of Denmark, Lyngby DUT . . . . . . . . . . Delft University of Technology (Delft, The Netherlands) DVD .......... Digital Versatile Disk [some standard DVD formats are: DVD-5 (4.7

GByte storage capacity, one layer per disk), DVD-9 (8.5 GByte, two layers per disk on one side, one layer is semi-permeable), DVD-10 (9.4 GByte, one layer per side and disk), DVD-18 (17 GByte, two layers per side and disk, one layer per side is semi-permeable)]

DWD .......... Deutscher Wetterdienst [German Weather Service, with seven forecast centers in Offenbach (HQ), Hamburg, Potsdam, Leipzig, Essen, Stuttgart, and Munich]. DWD employs over 3000 people in over 150 localities throughout Germany.

DWL .......... Doppler Wind Lidar (a active laser instrument based either on coherent heterodyne receiver technology or on incoherent direct receiver technology)

DYCOMS . . . . . . Dynamics and Chemistry of Marine Stratocumulus Experiment (campaign)

E EA ............ Environment Agency (of Japan) EADS ......... European Aeronautic, Defense and Space Company (a holding com

pany of DASA and a French pool group with Lagardere as the major


partner). Merger announcement of DASA (Germany) and Aerospatiale Matra (France) in Oct. 1999 - the merger was realized July 10, 2000 with DASA, Aerospatiale Matra, and CASA of Spain. The following units are part of EADS: Airbus, Ariane, Astrium (75% ), Dassault, Eurocopter, Eurofighter, and Rocket Systems.

EarlyBird ....... Commercial imaging satellite (B.4.1) EARSEC ....... European Airborne Remote Sensing Capabilities [program since 1990

between CEC (JRC in Ispra, Italy) and ESA] EARSeL ....... European Association of Remote Sensing Laboratories (since 1976) EarthCARE .... Earth Clouds Aerosol and Radiation Explorer (a proposed ESA core

mission) EarthKAM ..... Earth Knowledge Acquired by Middle school students (a NASA educa

tion program) The camera program started in 1996 as KidSat on Shuttle.

EARTHNET ... ESA Program since 1977. Earthnet refers to an ESA organization responsible for the ground segment of Earth Observation. Functions: acquisition, archiving and distribution of Earth science data.

Earth Watch Inc .. A US Earth observation company in Longmont, CO. Earth Watch was formed in January 1995 and is a joint venture of Ball Aerospace and WorldView Imaging Corporation (builder of EarlyBird and QuickBird)

Earth Watch ESA program [these are the operational (or pre-operational) serviceoriented missions addressing specific application areas of Europe]. The Earth Watch Initiative started in 2001 with the goal to secure for Europe an independent sustainable capability in operational Earth observation

EASE . . . . . . . . . . Experimental Assembly of Structures in Extravehicular Activity (Shuttle)

EASOE ........ European Arctic Stratospheric Ozone Experiment (campaign) EBCCD ........ Electron-bombarded CCD array EC ............ European Commission (since 1995: CEU (Commission of the Euro-

pean Union) ECD . . . . . . . . . . . Electron Capture Detector ECLIPS . . . . . . . . Experimental Cloud Lidar Pilot Study (campaign) ECMWF ....... European Centre for Medium-Range Weather Forecasts (located in

Reading, UK, founded in 1973). ECMWF is an international organization supported by the following European states: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, Turkey, United Kingdom. ECMWF has working arrangements with WMO, EUMETSAT and ACMAD (African Centre for Meteorological Applications for Development).

ECS ........... EOSDIS Core System (USA) EDAC ......... Earth Data Analysis Center (NASA contractor center at the University

of New Mexico, Albuquerque, NM, since 1964) EDAC ......... Error Detection and Correction (information processing term) EDC ........... EROS Data Center of the US Geological Survey (Sioux Falls, SD,

DAAC of NASA EOS Program for Land Processes) EDI ........... Electronic Data Interchange, (Format Specification according to ANSI

Standard X.12; (an existing but non-ISO Protocol) EDIFACT ...... Electronic Data Interchange for Administration, Commerce, and

Transport EDO . . . . . . . . . . Extended Duration Orbiter (Shuttle) EEA ........... European Environment Agency (since 1990, located in Copenhagen

since 1993, Denmark) EECF .......... Earthnet ERS-1 Central Facility (ESA facility at ESRIN, Italy) EELV .......... Extended Envelope Launch Vehicle (US Air Force launcher)


EEP ........... Earth Explorer Program (ESA) EEV ........... English Electric Valve, Chelmsford, UK (manufacturer of detectors) EEVT . . . . . . . . . Electrophoresis Equipment Verification Test (Shuttle) EFEDA ........ European Field Experiment in Desertification-threatened Areas

(campaign) e.g ............. abbreviation (Latin: exempli gratia) for example EGNOS ........ European Geostationary Navigation Overlay System (planned ESA

complementary system to GPS and GLONASS to provide Europe with GPS/GLONASS service availability, continuity and signal integrity)

EGS . . . . . . . . . . . European Geophysical Society EGS ........... Experimental Geodetic Satellite of NASDA, (Ajisai, E.3) EHF ........... Extremely High Frequency (30 - 300 GHz band) EHIC .......... Energetic Heavy Ion Composition Experiment EIRP . . . . . . . . . . Effective Isotropic Radiated Power EISAC ......... European Imaging Spectrometry Aircraft Campaign (1989-90) EISCAT . . . . . . . . European Incoherent Scatter Radar EIT . . . . . . . . . . . . Electro-bombardment Ion Thruster (electric proplusion system of

MMS, France) EIT . . . . . . . . . . . . Electromagnetically Induced Transparency ELAC . . . . . . . . . European Lidar Airborne Campaign ELDO ......... European Launcher Development Organization (since 1962) ELDO

is, along with ESRO, a predecessor organization of ESA ELDP .......... European Lake Drilling Project (campaign under PANASH) ELF ........... Extremely Low Frequency (30- 3000Hz) ELINT ......... Electronic Intelligence (used in the context of DoD missions) ELITE ......... European LITE (campaign) LITE = Lidar In-space Technology Ex

periment (Shuttle payload) ELOISE ....... European Land-Ocean Interaction Studies (campaign) El -Op . . . . . . . . . . El -Op Electro-Optics Industries of Rehovot, Israel (as of 2000 El-Op is

part of Elbit Systems Ltd. of Haifa, Israel) ELRAD ........ Earth-Limb Radiance Experiment (Shuttle payload) ELT-121.5 ...... Emergency Locator Transmitter (see COSPAS-S&RSAT, 1.6) EMAC ......... European Multi-Sensor Airborne Campaign (in the framework of

ESA/JRC collaboration) EMBRAER . . . . Empresa Brasileira de Astronautica SA (aircraft and space payload

manufacturer, Sao Jose dos Campos, SP, Brazil) EMEX ......... Equatorial Mesoscale Experiment (campaign) EMF . . . . . . . . . . Electromotive Force EMP . . . . . . . . . . . Electromagnetic Pulse EMSL . . . . . . . . . Environmental Monitoring Systems Laboratory (Las Vegas, NV, EPA

facility) . ENA ........... Energetic Neutral Atoms [neutral atoms or molecules created by

charge exchange between energetic ions (such as the Earth's radiation belts) and a cold neutral gas (such as the Earth's exosphere)]

ENEA ......... Ente perle Nuove tecnologie l'Energia e l'Ambiente (Rome, Italy) ENSO . . . . . . . . . El Nifio Southern Oscillation ENVISAT ...... Environmental Satellite (ESA, see D.9) EO . . . . . . . . . . . . Earth Observation E0-1 . . . . . . . . . . Earth Observing-1 (NASA SIC) EOCAP . . . . . . . . NASA's Earth Observations Commercial Applications Program, since

1987 (NASA's intent is to commercialize remote sensing technology originally developed to support scientific exploration)

EOL ........... End of Life EO PP . . . . . . . . . . Earth Observation Preparatory Programme (of ESA) EORF ......... Environment Measurements by the Real-Time Radiation Monitor

(Shuttle payload) EOS ........... Earth Observing System (NASA), D.ll


EOS . . . . . . . . . . . European Optical Society EOSAT ........ Earth Observation Satellite Company (Commercial distributor of

Landsat imaging data, located in Lanham, MD, since 1985, EOSAT is a joint venture of Lockheed Martin and Hughes Aircraft). Space Imaging Inc. (since 1994) of Thornton, CO of LM and E-Systems, acquired EOSAT in 1995. The new company was subsequently renamed into: Space Imaging EOSAT [distributor of IKONOS imagery, ERS-1/2, JERS and Radarsat data (USA), global distributor of IRS-1C/D imagery]. Since 1998 the company name is: Space Imaging. The owners of Space Imaging are: LM, E-Systems (of Raytheon Co, Lexington, MA ), Mitsubishi, Vander Horst (Singapore), Halla Heavy Industries (Korea).

EOSDIS . . . . . . . EOS Data and Information System EP . . . . . . . . . . . . Electric Propulsion (of spacecraft) EPA . . . . . . . . . . . Environmental Protection Agency (USA, since 1970) EPIRB ......... Emergency Position Indicating Radio Beacon (on COSPAS and

S&RSAT payloads) EPOCS ........ Equatorial Pacific Ocean Climate Studies (campaign) EPOCS . . . . . . . . European Committee on Ocean and Polar Sciences EPOP .......... European Polar Platform (old name, now POEM) EPOS . . . . . . . . . . European Proximity Operations Sensor (ESA test of GPS Tensor re

ceivers and an optical rendezvous sensor for Shuttle-Mir docking maneuvers on STS-84 and STS-86)

Equator-S ...... Solar Terrestrial Mission (K.9) ER-2 ........... Extended Range U-2 (US research aircraft of NASNARC) ERA ........... European Robotic Arm (of ESA on ISS) ERB . . . . . . . . . . . Earth Radiation Budget ERBS .......... Earth Radiation Budget Satellite (NASA), A.13 ERICA ........ Experiment on Rapidly Intensifying Cyclones over the Atlantic (cam

paign) ERIM ......... Environmental Research Institute of Michigan (HQ in Ann Arbor,

MI). ERIM is a nonprofit contract research organization in the field of remote sensing. In May 1997, ERIM was transformed into a profitseeking company and changed its name to "ERIM International." History: The Willow Run Laboratories were founded in 1947. In 1973 the Willow Run Laboratories team separated from the University of Michigan and became ERIM. -In 2000 ERIM International Inc. became part of Veridian Systems, the new company is called: Veridian ERIM International

EROS ......... Earth Resources Observation Systems (Data Center of USGS in Sioux Falls, SD, archive for Landsat and other data)

EROS . . . . . . . . . Earth Remote Observation System (B.5) ERS-1,2 ........ European Remote Sensing Satellite (ESA program), D.13 and D.14 ERS . . . . . . . . . . . Earth Resource Satellite ERSDAC ....... Earth Remote Sensing Data Analysis Center (Tokyo, Japan) ERTS-1 . . . . . . . . Earth Resources Technology Satellite (NASA satellite, in 1975 ERTS-1

was renamed to Landsat-1 and the entire ERTS program was renamed to Landsat)

ESA ........... European Space Agency (since 1975), ESA-HQ in Paris (ESA member states are: Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Italy, Netherlands, Norway, Spain, Sweden, Switzerland, and the United Kingdom; Canada is a cooperating country)

ESA/ESTEC . . . . ESNEuropean Space Research and Techaology Centre (ESA facility in Noordwijk, Netherlands)

ESNESOC . . . . . ESA/European Space Operation Centre (ESA facility in Darmstadt, Germany)

ESA!ESRIN .... ESA/European Space Research Institute (ESA facility, Frascati, Italy)


ESA-IRS ....... ESA- Information Retrieval Service (online database at ESRIN) ESAC .......... Earth Sciences Advisory Committee (ESA) ESA/PB-EO .... ESA/Programme Board- Earth Observation ESCAP . . . . . . . . (UN) Economic and Social Commission for Asia and the Pacific, Bang

kok, Thailand ESCAPE . . . . . . . Experiment of the Sun for Complementing the ATLAS Payload and for

Education (Shuttle Payload) ESE . . . . . . . . . . . Earth Science Enterprise [NASA program with the previous designa

tion of MTPE (Mission to Planet Earth)] ESEM . . . . . . . . . Evaluation of Space Environment Effects on Materials (Shuttle pay

load of NASNLaRC) ESEM experiments are focused on cosmic dust collection

ESF . . . . . . . . . . . European Science Foundation (Strasbourg, France) ESDIS . . . . . . . . . Earth Science Data and Information System (NASNGSFC) ESIC .......... Earth Science Information Center (USGS operates a network ofESICs

to distrubute Earth science data and related products) ESIS ........... European Space Information System (ESA data system) ESOC . . . . . . . . . European Space Operation Centre [ESA facility in Darmstadt, Germa

ny, since Sept. 1967; formerly ESDAC (European Space Data Center) underESRO]

ESRIN . . . . . . . . . European Space Research Institute (ESA facility in Frascati, Italy) ESRO ......... European Space Research Organization (founded in 1962 by ten Euro

pean countries; predecessor organization of ESA) ESSA .......... Environmental Science and Services Administration (this was a prede

cessor organization of NOAA) ESSP .......... Earth System Science Pathfinder (small-scale, low-cost, and quick-

turnaround NASA missions like QuikTOMS, VCL, GRACE, SORCE, ESSP-3 (formerly PICASSO-CENA), CLOUDSAT, VOLCAM, etc.)

ESTEC . . . . . . . . European Space Research and Technology Centre (ESA facility in Noordwijk, Netherlands)

ETALON . . . . . . Russian passive satellite series for geodetic measurements, E.4 ETHZ . . . . . . . . . Eidgenoessische Technische Hochschule, Zurich (Swiss Federal Insti-

tute of Technology, Ziirich) ETHZ/IGP ..... ETHZ/Institute of Geodesy and Photogrammetry ETL . . . . . . . . . . . Electrotechnical Laboratorium (of MITI, Japan) ETS ........... Engineering Test Satellite (NASDA technology series, Japan) ETSI .......... European Telecommunications Standards Institute (since 1988) EU ............ European Union (formerly EC = European Community) EUCREX ...... European Cloud and Radiation Experiment (campaign) EUMETSAT . . . . European Organization for the Exploitation of Meteorological Satel-

lites (Darmstadt, Germany, since 1986 - operation of the Meteosat and the future Me tOp systems). EUMETSAT member states are: Austria, Belgium, Denmark, Finland, France, Greece, Germany, Ireland, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, Turkey, and the United Kingdom.

EurasSpace . . . . . EurasSpace GmbH, Munich; Euro-Asian Space venture between DASA of Germany and CASC (Chinese Aerospace Corp. of Beijing); builders of telecommunication satellites (Sinosat-1, etc.)

EURIMAGE . . . European Consortium for Satellite Image Dissemination (Rome, Italy -a commercial data distributor. The consortium is made up by the following companies: SSC, MATRA, NRSC and Domier)

EURECA . . . . . . European Retrievable Carrier (platform deployed and retrieved on Shuttle) 1.5

EURISY . . . . . . . European Association for ISY (one of two ISY organizers in Europe, see SAFISY)

Eurockot . . . . . . . Eurockot Launch Services GmbH, Bremen, Germany. A joint venture company between Russia's Khrunichev and Germany's DASA. The


launcher is the Rockot vehicle, built by KhSC (Khrunichev State Research and Production Space Center), Moscow. Rockot is a modified version of Russia's SS-19 missile. The first launch demonstration of a Rockot vehicle occurred on May 16, 2000 from Plesetsk with Simsat-1 and -2, two dummy payloads.

EUROLAS ..... European Laser Stations (ground network of SLR stations) EUROPTO ..... A joint venture between EOS (European Optical Society) and SPIE

(Society of Photo-Optical Instrumentation Engineering) Eurospace ...... The association of European space industry, Paris, since 1961 Eutelsat . . . . . . . . European Telecommunications Satellite Organization EUV .......... Extreme Ultra Violet (spectral range), see also: XUV EXOS ......... Exospheric Observations, ISAS program (K.10) EXPRESSO . . . . Experiment for Regional Sources and Sinks of Oxidants (campaign)

F FAA ........... Federal Aviation Administration (regulatory agency for all civil avi-

ation in the Department of Transportation, USA) FACH ......... Fuerza Aerara de Chile (Chilenian Air Force) FAGS . . . . . . . . . . Federation of Astronomical and Geophysical Services FAISAT ........ Final Analysis Inc. Satellite (C.2) FAO . . . . . . . . . . . Food and Agriculture Organization (of the UN) FARE . . . . . . . . . . Fluid Acquisition and Resupply Experiment (Shuttle) FASat-Alfa ..... Fuerza Aerea Satellite- Alfa (D.40.12) FASINEX ...... Frontal Air-Sea Interaction Experiment (campaign) FAST .......... Fast Auroral Snapshot Explorer (GSFC mission, K.21.2) FAST .......... Fore-Aft Scan Technique (radar) FASTEX ....... Fronts & Atlantic Storm Track Experiment (campaign) FATE .......... FIRST ATSR Tropical Experiment (campaign) FBG ........... Functional Cargo Block (first element ofiSS also referred to as Zarya) FCC ........... Federal Communications Commission (Washington, DC, USA) FDDI .......... Fiber Distributed Data Interface FDMA ......... Frequency Division Multiple Access (access scheme) FDP ........... Fluorescent Dye Particles (a tracer technique in lidar observations) FEA . . . . . . . . . . . Fluid Experiment Apparatus (Shuttle) FEC ........... Forward Error Correction (transmission protocol technique) FEEP . . . . . . . . . . Field Effect Electric Propulsion Feng-Yun (FY) . . Chinese meteorological satellite series, G.3 FFT . . . . . . . . . . . Fast Fourier Transform FET ........... Field-Effect Transistor (JFET =Junction Field-Effect Transistor) FFSK .......... Fast Frequency Shift Keying (modulation technique) FGAN ......... Forschungsgesellschaft fiir Angewandte Naturwissenschaften (Ger

man Defense Research Laboratory, Wachtberg, Germany) FGGE ......... First GARP Global Experiment (campaign) FhG ........... Fraunhofer Gesellschaft (in honor of Joseph von Fraunhofer, 1787 -

1826), a leading organization of applied research in Germany (HQ in Munich). FhG operates 47 research institutes in Germany with about 8500 employees. About 2/3 of FhG research is through contracts for industry and government. There are also FhG institutes in USA and Asia. Only a few institutes are listed here:

FhG/IAF ....... Fraunhofer Gesellschaft/Institut fiir Angewandte Festki:irperphysik (development of detectors), Freiburg, Germany

FhG/IFU ....... Fraunhofer Gesellschaft/Institut fiir Atmospiiheren und Umweltforschung (Institute of Atmospheric and Environmental Research), Garmisch-Partenkirchen, Germany

FhG/IOF ....... Fraunhofer Gesellscahft/Institut fiir Angewandte Optik und Feinmechanik (Institute of Applied Optics and Precision Engeneering), Jena, Germany


FhG/IPM ....... Fraunhofer Gesellschaft/lnstitut fiir Physikalische MeBtechnik (Institute of Physical Measurement Techniques), Freiburg, Germany

FHT ........... Frequency Hopping Telemetry (a communication access method) FIRAS ......... P. N. Lebedev Physical Institute of the Russian Academy of Sciences

(RAS), Moscow. FIRAS was established in 1967 as part of IKI. Since 1991 it is named AKTs FIRAS (radio astronomy)

FID . . . . . . . . . . . Flame Ionization Detector FIFE .......... First ISLSCP Field Experiment (campaign) FILE . . . . . . . . . . Feature Identification and Location Experiment (part of OSTA-1 pay

load on Shuttle STS-2 in Nov. 1981) FIMR .......... Finnish Institute of Marine Research (Helsinki, Finland) FINDS ......... Foundation of the International Non-Governmental Development of

Space (USA, created in 1997) FIR ........... Far infrared: from about 10- 1000 ~tm (note: 1000 ~tm = 1 mm) FIRE .......... First ISCCP Regional Experiment (campaign) FIRESCAN .... Fire Research Campaign Asia-North (IGBP-IGAC-BIBEX campaign) FIRESCHEME . Fire Information Systems Research in the Socio-Culture, History and

Ecology, of the Mediterranean Environment (campaign) FLINN ......... Fiducial Laboratories for an International Network (a global network

supporting Crustal Dynamics Test Sites) FLIR .......... Forward Looking Infrared (sensor) FM ............ Frequency Modulation (modulation technique of the main carrier) FMC .......... Forward Motion Compensation FM/CW ........ Frequency Modulation/Continuous Wave (a radar measurement tech

nique to obtain range information- a sequence of FM/CW echoes contains both, range and Doppler information)

FMI ........... Finnish Meteorological Institute (Helsinki, Finland) FMS ........... Flight Management System (avionics) FOA ........... Forsvarets Forskningsanstalt (National Defense Research Establish-

ment, Department of Information Technology, Linkopping, Sweden) FQG ........... Fiber-Optic Gyroscope (an angular rate gyro) FOMI ......... Hungarian Remote Sensing Center, Budapest, Hungary FOO . . . . . . . . . . . Flight of Opportunity FOR ........... Field of Regard (total with of aground imaging surface that is within the

pointing potential of a sensor. Note: the FOV (or swath width) is always contained in the FOR)

FORTE ........ Fast On-Orbit Recording of Transient Events (LANL, A.16) FOV . . . . . . . . . . . Field of View FPA . . . . . . . . . . . Focal Plane Array (also: Focal Plane Assembly - detector assembly of

an imager instrument) FPGA . . . . . . . . . Field Programmable Gate Array FRAM ......... Ferroelectric Random Access Memory (a chip technology) FREJA ......... Swedish Solar-Terrestrial Mission (K.ll) FSK ........... Frequency Shift Keying (modulation technique) FTAM ......... File Transfer Access and Management (OSI File Transfer Method) FTFPV ......... Flexible Thin-Film Photovoltaic (technology) FTIR ........... Fourier Transform Infrared (radiometer or spectrometer) FTS . . . . . . . . . . . Fourier Transform Spectrometer FUV ........... Far Ultraviolet (spectral region 90- 125 nm) FWG .......... Forschungsanstalt der Bundeswehr fur Wasserschall und Geophysik

(Kiel, Germany) FWHM ........ Full-Width-Half-Maximum (of distribution curve) FZJ ........... Forschungszentrum Jiilich (Germany, old name was KfA) FZK ........... Forschungszentrum Karlsruhe (Germany, old name was KfK) FZK/IMK . . . . . . FZK (Forschungszentrum Karlsruhe )/lnstitut fiir Meteorologie und

Klimaforschung (Institute of Meteorology and Climate Research)


G

Ga ............ Gallium (detector material) GaAs . . . . . . . . . . Gallium Arsenide (a material used for solar panels, for detectors, and

for fast computer chips) Gain . . . . . . . . . . . Galileo Industries SA, located in Brussels, Belgium (a joint venture of

Astrium, Alenia Spazio, and Alcatel Space, founded May 25, 2000) GalnPz ......... Gallium Indium Phosphide (solar cell type) GaN ........... Gallium Nitride (used in GaN photoconductive detectors) GAC ........... Global Area Coverage (the term is used for AVHRR data of NOAA) GAF ........... Gesellschaft fiir Angewandte Fernerkundung, Munich (since 1985,

German commercial distributor of Earth observation data, such as Resurs data, Landsat data, IRS-1 C/D data (via EO SAT), representative of EURIMAGE and SPOT-IMAGE in Germany, distributor for SOVINFORMSPUTNIK data, Radarsat data distributor for Germany, etc.

GABLE ........ Global Atmospheric Backscatter Lidar Experiment (campaign) GADACS ...... GPS Attitude Determination and Control Experiment (a GSFC GPS

instrument package on Shuttle SPARTAN) GADFLY ....... GPS Attitude Determination Flyer (experiment on Lewis S/C) GAIM ......... Global Analysis, Interpretation and Modeling (IGBP project) GALE ......... Genesis of Atlantic Lows Experiment (airborne campaign in 1986) Galileo Industries Galileo Indus ties SA is a European joint venture of the following com-

panies(to define and build the Galileo System): Alenia Spazio of Rome, Alcatel Space of Paris, Astrium Ltd. of Stevenage, UK, and Astrium GmbH of Friedrichshafen, Germany.

GAME ......... GEWEX-related Asian Monsoon Experiment (campaign) GAMES ....... Gravity and Magnetic Earth Surveyor (a NASNGSFC mission) GANDER ...... Global Altimeter Network Designed to Evaluate Risk (an SSTL, UK

constellation planned to be launched in 2002)+ + + + GANE ......... GPS Attitude Navigation Experiment (NASA Shuttle payload) GARP ......... Global Atmospheric Research Program (ofWMO, since 1968) GAS ........... Get-Away Special (Shuttle canisters) GATE ......... GARP Atlantic Tropical Experiment (campaign) GAUSS ........ Galaktische Ultraweitwinkel Schmidt System, Shuttle payload (Galac-

tic super wide angle Schmidt system) GAW .......... Global Atmosphere Watch (WMO) GBA .......... GAS Bridge Assembly (Shuttle payload) GBRN ......... Global Baseline Radiation Network (WCRP) GC . . . . . . . . . . . . Gas Chromatograph GCIP .......... GEWEX Continental-Scale International Project GCM .......... General Circulation Model (atmospheric and climate research) GCMD ........ Global Change Master Directory (at NASNGSFC since 1989) GCOM ........ Global Change Observation Mission (NASDA) GCOS ......... Global Climate Observing System (ofWMO, IOC, UNEP, and ICSU) GCOS/JSTC .... GCOS/Joint Scientific and Technical Committee (Geneva, Switzer-

land) GCP ........... Glow Cryoph Payload (DoD Shuttle payload) GCTE ......... Global Change and Terrestrial Ecosystem (IGBP core program) GE ............ General Electric Co., Fairchild, CT, USA Ge ............ Germanium (detector material) GeGa .......... Germanium Gallium (detector) GEIA .......... Global Emissions Inventory Activity (IGBP/IGAC focus 6 activity) GEMINI ....... NASA program of the 1960s GEMINUS ..... Galileo European Multimodal Integrated Navigation User Service GEMS . . . . . . . . . Global Environment Monitoring System (of UNEP) GENESIS ...... Galileo European Network of Experts to Support the European Com

mission


GEO .......... Geostationary Earth Orbit (or geosynchronous orbit with zero inclination, the altitude is about 35,786 km)

GeoLITE ....... Geosynchronous Lightweight Technology Experiment (NRO funded communications satellite)

GEO-IK ....... Russian S/C for solid Earth research, E.5 GEOKhl RAN .. Vernadskiy Institute for Geochemistry and Analytical Chemistry of

RAN, Moscow; since 1947, participation in programs: Luna, Venera, Salyut, MIR, Vega, Phobos, Voyager, Magellan, Mars Observer

GEOMAR ..... Research Center for Marine Geosciences (U. of Kiel, Germany) GEOS ......... Geostationary Satellite (ESA experimental program) E.6 GEOS ......... Geodetic Earth Orbiting Satellite, E.7.1, E.7.2 GEOS-3 ........ Geodynamics Experimental Ocean Satellite, E. 7.3 (GEOS-3 is the first

radar altimeter mission, end of mission in 1978) GEOS&R ...... Geostationary Search and Rescue (system) GEOSAT ....... US Navy satellite (altimeter mission), E.8 GEOTAIL ...... Japanese (ISAS) mission to study the structure and dynamics of the

geomagnetic tail (part of ISTP), K.13 GEOWARN .... Global Emergency Observation Warning and Relief Network (in plan-

ning phase by NASNMSFC, etc.) GER .......... Geophysical & Environmental Research Corp. (Millbrook, NY, USA) GEWEX ....... Global Energy and Water Cycle Experiment (WMO program) GFLOPS ....... Billion Floating Point Operations per Second (109 - a measure of com

puter processing power) GF0-1 ......... Geosat Follow-On (Satellite), E.9 GFU ........... Geophysical Institute of the Academy of Sciences of the Czech Repub

lic, Prague GFZ ........... GeoForschungsZentrum (Potsdam, Germany, since 1992) GGS . . . . . . . . . . . Global Geospace Science (US program within ISTP with two space

craft: Wind and Polar) GGSE . . . . . . . . . Gravity Gradient Stabilization Experiment. A technology satellite se

ries (GGSE-1 to GGSE-5) launched by the US military (NRL of DoD) from Vandenberg AFB aboard Thor Agena-D rockets. GGSE-1 (39 kg mass): launch Jan. 11, 1964 into a 900 km altitude orbit with an inclination of 69.9°; GGSE-2 and GGSE-3 (each S/C of 4 kg mass): launch March 9, 1965; GGSE-4and -5 (each S/Cof4 kg mass): launch May 31, 1967

GGTS-1 ........ Gravity Gradient Test Satellite-! (of the USAF was launched June 16, 1966 from Cape Canaveral)

GHCC ......... Global Hydrology and Climate Center (at NASNMSFC, Huntsville) GHCD ......... Growth Hormone Crystal Distribution (Shuttle experiment) GIAC .......... GPS Interagency Advisory Council G IF . . . . . . . . . . . Graphics Interchange Format of Compuserve (8-bit color format, used

in HTML, etc.) GIM ........... Global Integration and Modeling (IGBP/IGAC focus 6 activity) GIMEX ........ Greenland Ice Margin Experiment (campaign) GIPME ........ Global Investigation of Pollution in the Marine Environment GIS . . . . . . . . . . . . Geographic Information System (an archive in particular for forestry

data) GISP .......... Greenland Ice Sheet Project GISS .......... Goddard Institute for Space Studies (New York, NY, since 1961 -a

NASNGSFC facility at Columbia University) GKNPT Khrunichev Moscow; Leading company in the development, production, test-

ing, and operation of launch vehicles and spacecraft, utilization of Proton. Participation in programs: Venera. Mars, Luna, Kosmos, Phobos, Vega, Gorizont, Salyut, MIR, Almaz, Energia-Buran, Zond, etc.

GKSS .......... Gesellschaft fiir Kernergieverwertung in Schiffbau und Schiffahrt (Geesthacht, Germany)


GLAS .......... Geoscience Laser Altimeter System (previously GLRS) GLIS . . . . . . . . . . Global Land Information System (an online land data directory guide,

a public information system operated by USGS at EROS Data Center) Glavkosmos ..... Russian space organization agency with the objective to develop the

commercial side of space activities (created in 1985) GLO .......... Glow Experiment (Shuttle payload) GLOBE ........ Global Backscatter Experiment (campaign) GLOBSAT ..... Proposed Earth Observation Satellite by the French Earth Science

Community. GLOCARB ..... Global Tropospheric Carbon Dioxide Network (IGBP/IGAC pro-

gram) GLOCHEM .... Global Atmospheric Chemistry Survey (IGBP/IGAC program) GLOMR ....... Global Low Orting Message Relay (DARPA SIC flown on STS-61A) GLONASS ..... Global Orbiting and Navigation Satellite System (USSR), H.3 GLONET ...... Global Tropospheric Ozone Network (IGBP/IGAC program) GLOSS ........ Global Sea Level Observing System (of IOC) GLRS ......... Geoscience Laser Ranging System (EOS Sensor), renamed in 1992

GLAS = Geoscience Laser Altimeter System GMES . . . . . . . . . Global Monitoring for Environment and Security (European initia

tive) GMS .......... Geostationary Meteorological Satellite, Operational Program of JMA

(Japan Meteorological Agency), F.3 OMSK ......... Gaussian Minimum Shift Keying (modulation technique) GN&C ......... Guidance Navigation and Control GNSS .......... Global Navigation Satellite System (a future civil satellite navigation

system) GOALS ........ Global Ocean-Atmosphere-Land System (CLIVAR subprogram) GOBEX ....... Gotland Basin Experiment (campaign) GOCE . . . . . . . . . Gravity Field and Steady-State Ocean Circulation Experiment (core

mission in ESA's Earth Explorer Program) GOES ......... Geostationary Operational Environmental Satellite (NOAA Series),

F.4 GOFS ......... Global Ocean Flux Study (program) GOMS ......... Geostationary Operational Environmental Satellite (Russian geosta

tionary meteorological satellite series (at longitude 76 deg. East), F.5 GOOS ......... Global Ocean Observing System [a joint program of the Intergovern

mental Oceanographic Organization, WMO (World Meteorological Organization), UNEP (United Nations Environmental Program), and the International Council for Science]. GOOS integrates real-time insitu and satellite observations with numerical model to form modelbased information products for a variety of applications.

GORC ......... Global Ocean Carbon Research Program GORS ......... General Organization of Remote Sensing (since 1986, Damascus, Syr-

ia), Space Agency of Syria GOS . . . . . . . . . . . Global Observing System (WWW) GOSAMR-1 . . . . Gelatin of Sols: Applied Microgravity Research-1 (Shuttle experiment) GOSIP ......... Government Open System Interconnection Profile ( US Government

Standard, GOSIP is a subset of OSI) GOSNIIAS ..... State Research Institute of Aviation Systems (Moscow, Russia) GP-B .......... Gravity Probe-B Relativity Mission (E.12) GPCC ......... Global Precipitation Climatology Center, (since 1988, located at the

German Weather Service (DWD) in Offenbach, Germany, collection of raingauge-measured monthly precipitation data, worldwide)

GPCP .......... Global Precipitation Climatology Project (by ICSU and WMO) GPS . . . . . . . . . . . Global Positioning System, H.4 GPS DTO ...... GPS Development Test Objective (Shuttle payload) GRACE . . . . . . . . Gravity Recovery and Climate Experiment


GRAS ......... Ground Regional Augmentation Ssytem (within the framework ofEGNOS)

GRDC ......... Global Runoff Data Center (Bundesanstalt fiir Gewasserkunde- Federal Institute of Hydrology, Koblenz, Germany)

GRGS ......... Groupe de Recherches de Geodesie Spatiale (Grasse and Toulouse, France)

GRID ......... (UNEP) Global Resources Information Database (at EDC) for the purpose of analyzing environmental data

GRIP .......... Greenland Icecore Project GRSS .......... Geoscience and Remote Sensing Society GSC . . . . . . . . . . . Geological Survey of Canada GSD ........... Ground-Sampling Distance (spatial resolution). GSFC . . . . . . . . . . Goddard Space Flight Center in Greenbelt, MD (DAAC of NASA

EOS Program) GSI ............ Geological Survey Institute (Japan) GSLV .......... Geosynchronous Satellite Launch Vehicle (a three-stage ISRO launch-

er, since 1999, of PSLV heritage) GSM . . . . . . . . . . Global System for Mobiles (digital cellular standard of ETSI) GSOC ......... German Space Operations Center (DLR facility in Oberpfaffenhofen) GSTDN ........ Ground-Station Tracking and Data Network (old NASA network) G!T ............ (receiver) Gain I (noise) Temperature GTCP .......... Global Tropospheric Chemistry Program (NSF program) GTE ........... Global Tropospheric Experiment (a NASA program) GTE/CITE . . . . . Global Tropospheric Experiment/Chemical Instrumentation Test and

Evaluation (campaigns) GTO . . . . . . . . . . . Geosynchronous Transfer Orbit GTOS ......... Global Terrestrial Observing System (WMO, UNESCO, IOC, FAO,

ICSU) GTS ........... Global Telecommunications System (of the World Meteorological Or

ganization (WMO)) GULFEX ...... Gulf Experiment (campaign)

H HzO ........... Water HzOz . . . . . . . . . . Hydrogen peroxide HALE ........ ·. High Altitude Long Endurance (campaign) HAPEX ........ Hydrologic and Atmospheric Pilot Experiment (campaign) HaRP .......... Hawaiian Rainbow Project (campaign) HBr . . . . . . . . . . . Hydrogen bromide HBT . . . . . . . . . . . Heflex Bioengineering Test (Shuttle) HCMM ........ Heat Capacity Mapping Mission (NASA sensor), A.18 HCHO ......... (CHzO) Formaldehyde HCI ........... Hydrogen chloride HCT ........... HgCdTe (detector type, see also MCT) HDDT ......... High Density Digital Tape HDP ........... Human Dimensions Programme (of ISSC) HDT . . . . . . . . . . High Density Tape HDLC ......... High-Leve!Data Link Control (bit-oriented protocol) HEB .......... Hot Electron Bolometer (receiver type used in microwave spectrome

ters, etc.) HELCOM ...... Helsinki Commission (since 1974, an intergovernmental organization

of all countries surrounding the Baltic Sea to protect the Baltic Sea) HELIOS-1 ...... A European military reconnaissance satellite program (Earth observa

tion) sponsored by France (78.9% ), Italy (14.1%) and Spain (7% ). Helios-1A was launched July 7, 1995. Helios-lB was launched Dec. 3, 1999 on an Ariane 4 vehicle from Kourou. Both satellites were built by MMS


of Toulouse. Helios-1B, nearly an identical twin of Helios-1A, has a launch mass of 2544 kg (design life of 5 years, power = 2.2 kW). The Helios SIC bus is almost identical to the SPOT-4 platform. Attitude is measured by star sensors and two-axis gyros, actuators are reaction wheels and magnetic torquers. Both SIC are in a sun-synchronous orbit (altitude= 680 km, inclination =98°, period= 98 minutes), 180° apart to optimize coverage. The optical imaging system is referred to as EPV (Ensemble de Prise de Vues ), built by Alcatel Space, it uses CCD line array detectors and provides a spatial resolution of about 1 m. Onboard storage is provided by two digital tape recorders for each SIC, each with a capacity of 120 Gbit. Helios-lB has in addition a solid state memory of 9 Gbit. All imagery is encrypted and downlinked in X -band at 50 Mbitls (TT&C encrypted inS-band at 2 kbitls). CNES provides SIC operations from Toulouse. The Helios ground segment comprises three user centers at Creil (Italy), Madrid (Spain), and CPFH (Main Helios Center France). Imagery is received at ground stations of the three partner countries [Maspalomas (Spain), Colmar (France), and Leece (Italy)]. 2109)

HELSTF . . . . . . . High Energy Laser Systems Test Facility [a US DoD national test facility at WSMR (White Sands Missile Range), NM, supporting laser research, development, test and evaluation. HELSTF was established in 1985 as a tri-service test and evaluation facility for all high energy laser work. MIRACL (Mid-Infrared Advanced Chemical Laser) is located atWSMR]

HEMT ......... High Electron Mobility Transistor (receiver type for microwave spectrometers)

HEO . . . . . . . . . . Highly Elliptical Orbit HERCULES .... Hand-held, Earth-oriented, Real-time, Cooperative, User-friendly,

Location-targeting and Environmental System (Shuttle experiment) HES . . . . . . . . . . . Hitchhiker Ejection System. HES provides a capability to eject a pay

load from a GAS (Get Away Special) canister on Shuttle. HESS . . . . . . . . . . High-Latitude Ecosystems as Sources and Sinks of Trace Gases (I GBP I

IGAC) HETE . . . . . . . . . High Energy Transient Experiment (MIT payload, built by AeroAstro

of Herndon, VA) HF . . . . . . . . . . . . High Frequency (3 - 30 MHz band) HF . . . . . . . . . . . . Hydrogen fluoride HgCdTe ........ Mercury Cadmium Telluride (mercadtelluride, a detector material)

also referred to as MCT and HCT Hglz ........... Mercury Iodine (a detector material) HGF ........... Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszen

tren, Bonn (named after Hermann von Helmholtz, 1821 - 1894). Sixteen German research centers are members of HGF, an association with the objective to coordinate and foster interdisciplinary research, to share expensive technical equipment of their infrastructure, to cooperate on long-term system solutions, and to transfer new technology for industrial applications. All HGF centers are government-funded, they employ a total of about 23,000 persons with a budget of 3.6 billion DM in 1996. The following institutions are members of HGF: AWl (Alfred-Wegener-Institut fiir Polar- und Meeresforschung, since 1980, Bremerhaven and Potsdam) DESY (Deutsches Elektronen Synchrotron, Hamburg, since 1959) DKFZ (Deutsches Krebsforschungszentrum, Heidelberg, since 1964) DLR (Deutsche Forschungsanstalt fiir Luft- und Raumfahrt) FZK (Forschungszentrum Karlsruhe) GBF (Gesellschaft fiir Biotechnologische Forschung, Braunschweig)

2109)"Helios, Europe's eye in the sky," CNES Magazine, No 7, Nov. 1999


GFZ (GeoForschungsZentrum Potsdam, since 1992) GKSS (Gesellschaft fiir Kernergieverwertung in Schiffbau und Schiffahrt, Geesthacht) GMD (Gesellschaft fiir Mathematik und Datenverarbeitung, since 1968, German National Research Center of Information Technology, St. Augustin, and Darmstadt) GSF (Forschungszentrum fiir Umwelt und Gesundheit, Neuherberg) GSI (Gesellschaft fiir Schwerionenforschung, Darmstadt) HMI (Hahn-Meitner-Institut, Berlin) IPP (Max-Planck-Institut fiir Plasmaphysik, Garching) KFA (Forschungszentrum Jiilich) MDC (Max-Delbriick-Zentrum fiir Molekulare Medizin, Berlin) UFZ (Umweltforschungszentrum Leipzig-Halle)

HH . . . . . . . . . . . . Hichthiker (a Shuttle flight carrier system offered by NASA for small payloads, offering the provision of extended functional features) HH-S stands for 'sidewall mounting,' HH-C stands for 'cross bay mounting'

HH . . . . . . . . . . . . Horizontal transmit - Horizontal receive polarization HIP ........... Heterojunction Internal Photoemission (detector technology) HN03 ......... Nitric acid HOx (HOx) ..... Odd hydrogen (OH, HOz, HzOz) HOCI .......... Hypochlorous acid HOLOP ........ Holographic Optics Laboratory (Shuttle D2 mission) HOST . . . . . . . . . HST Orbital Systems Test Platform (Shuttle payoad) HPCG ......... Hand-held Protein Crystal Growth (Shuttle payload) HPP ........... Heat Pipe Performance (Shuttle experiment) HPT ........... Heterojunction Phototransistor (optoelectronic component which

combines both optical detection and electrical gain in a single element) HPTE ......... High Precision Tracking Experiment (Shuttle payload) HRPT . . . . . . . . . High Resolution Picture Transmission (NOAA broadcast technique in

S-hand at frequencies of 1698.0 and 1707.0 MHz; data from all AVHRR channels (plus TOYS and SEM) is provided at fulll.1 km resolution)

HRSGS-A . . . . . . High Resolution Shuttle Glow Spectroscopy (Shuttle payload) HRTS .......... High Resolution Telescope and Spectrograph (Shuttle, Spacelab-2 sr, a

~0 em, f/15 Gregorian telescope, spectrograph in UV range 1170-1700 A, and a spectroheliograph observing at 1550 A)

HSC ........... Hughes Space & Communications Company (since 1961 ), an operating unit of Hughes Electronics Corporation, Los Angeles, CA. HSC is a manufacturer (world leader) of communication satellites (over 40% of market share). Provider of several standard platforms like HS 376 for spin-stabilized satellites, the HS 601 series is body-stabilized; in 1995 HSC introduced the body-stabilized HS 702 platform. Manufacturer of Syncom (first communications satellite, launch 1963), ATS-1 (first GEO weather satellite, launch in 1966), Pioneer (Venus Probe, 1978), Galileo (Jupiter Probe, launch 1989). Military satellite builder.- In January 2000, the HSC along with subsidiaries Hughes Electron Dynamics and Spectrolab were sold to the Boeing Company. They were reorganized into a business unit called "Boeing Satellite Systems."

HSCT .......... High-Speed Civil Transport (USA) HST ........... Hubble Space Telescope (Shuttle launch) HSRP .......... High-Speed Research Program (NASA) HTML . . . . . . . . . HyperText Markup Language HTS ........... High-(Tc) Temperature Superconductivity, refers to material tempera

ture Tc levels above those of liquid helium [the technology is employed in sensor design, thin-film applications, MRI (Magnetic Resonance Imaging), wireless communication filters, and ultra-fast computer chips]


HTSQUID ..... High-(Tc) Temperature SQUID (Superconducting Quantum Interference Device)

HTTP . . . . . . . . . . HyperText Transfer Protocol Hughes . . . . . . . . Hughes Electronics Corporation, a worldwide operating company with

HQ in Los Angeles, CA (a wholly owned subsidiary of General Motors Corporation founded in 1985). The conglomerate consists of: Hughes Aircraft Company, Hughes Telecommunications & Space (largest manufacturer in the world of telecommunication satellites), Hughes Network Systems, DIRECTV Inc., and Delco Electronics Corporation. HSC is part of Hughes Telecommunications & Space. In 2000, Hughes Electronics Corporation sold its satellite manufacturing business to Boeing Company.

Hughes (HAC) .. Hughes Aircraft Company, (since 1932, founded by Howard Hughes), part of Hughes Electronics Corporation, with HQ in Arlington, VA, a technology company with three major operating units: Information Systems (Reston, VA), Sensor & Communications Systems, and Weapons Systems. SBRC (as of 1996 SBRS, builder of Landsat instruments, MSS, TM, monolithic infrared focal plane arrays, etc.) is part of Sensor & Communications Systems

HUT .......... Helsinki University of Technology (Helsinki, Finland) HUT .......... Hopkins Ultraviolet Telescope (part of Shuttle ASTRO observatory) HV . . . . . . . . . . . . Horizontal transmit - Vertical receive polarization HYDROMET .. Committee for Hydrometeorology (USSR/CIS agency in the field of

Meteorology) HypSEO . . . . . . . HyperSpectral Earth Observer (an ASI mission in preparation,

planned flight in 2003) HWRP ......... Hydrology and Water Resources Programme (WMO)

I IAA ........... International Academy of Astronautics (Paris, France) IAE . . . . . . . . . . . Inflatable Antenna Experiment (Shuttle) IADC .......... Inter-Agency Space Debris Coordination Committee IAF ........... International Astronautical Federation (Paris) IAFE .......... Institute of Astronomy and Space Physics (Argentina) lAG . . . . . . . . . . . International Association of Geodesy IAHS . . . . . . . . . . International Association of Hydrological Sciences IAI ............ Israel Aircraft Industries (government-owned company, ofLod, Israel) IAI/MBT . . . . . . . IAI/Mifal Beth. MBT stands for the Hebrew translation of MIFAL

BETH (or its abreviation of MABAT) which means 'the second plant,' since it was the second plant established by IAI in the 1960s. The Hebrew name of MABAT remained with the corresponding English acronymofMBT.

lAIN .......... International Association of Institutes of Navigation (since 1975) IAMAP . . . . . . . . International Association of Meteorology and Atmospheric Physics lAMAS . . . . . . . . International Association of Meteorology and Atmospheric Sciences lAP . . . . . . . . . . . . Institute of Atmospheric Physics, Moscow IAPSO . . . . . . . . . International Association for the Physical Sciences of the Oceans (one

of seven associations ofiUGG, which in turn is a union ofiCSU) lAS ............ Institut d'Astrophysique Spatiale (Verrieres-le-Buisson, France, lab is

part of CNRS) IASC .......... International Arctic Science Committee (Arctic Centre, University of

Lapland, Finland) IASIS . . . . . . . . . . Interbranch Association Sovinformsputnik (commercial distributor of

imagery from Russian defense satellites, Moscow) IAU ........... International Astronomical Union IBAMA ........ Instituto Brasileiro do Meio Ambientes Dos Recursos Naturais Reno

vaveis (Brazil)


IBC ........... Impurity Band Conduction (detector technology) IBFRA ......... International Boreal Forest Research Association (since 1991) IBFRA-SRF .... IBFRA- Stand Replacement Fire (working group) IBSE . . . . . . . . . . Initial Blood Storage Experiment (Shuttle payload) IBSFC . . . . . . . . . International Baltic Sea Fishery Commission IBSS . . . . . . . . . . . Infrared Background Signature Survey (satellite of the USAF deployed

on STS-39) IBSS was retrieved by the Shuttle on May 2, 1991. ICA ........... International Cartographic Association ICAE .......... International Conference on Atmospheric Electricity ICAO .......... International Civil Aviation Organization ICAT .......... Incubator-Cell Attachment Test (Shuttle) ICBC .......... IMAX Cargo Bay Camera (Shuttle), a 65 mm color motion picture

camera ICBM .......... Intercontinental Ballistic Missile. Russia offers commercially four

types of converted ICBMs for satellite launches. The types "Rockot" and "Strela" are based on the SS-19 Stiletto missile; "Dnepr" is based on the SS-18 Satan missile; "Start" is a converted SS-20 missile. The Rockot launch vehicle Rockot is a joint venture of Eurockot Launch Services GmbH, Bremen, Germany and of KhSC (Khrunichev State Research and Production Space Center), Moscow. ISC Kosmotras of Moscow markets the Dneprvehicle. The Start (Start-1) vehicle is marketed by Puscovie Uslugi of Moscow.

ICC ........... Instrument Control Center (EOSDIS Facility) ICC ........... Integrated Cargo Carrier (Shuttle payload, first flown on STS-96). ICC

is an unpressurized flat bed pallet and keel yoke assembly. Constructed of aluminum, it is 2.5 m long, 4.5 m wide and 25 em thick and has the capability to carry cargo (up to about 1350 kg) on both faces of the pallet, both atop and below. The ICC is used by astronauts throughout the construction of the Space Station as it transports hardware from locations on the station's exterior to work sites on the truss assemblies.

ICE ........... International Cirrus Experiment (campaign) ICE ........... International Cometary Explorer (renamed ISEE-3 mission), K.18.2 ICES .......... International Council for the Exploration of the Sea ICET .......... International Center for Earth Tides ICIC ........... Intercalibrations/Intercomparisons (IGBP/IGAC focus 7 activity) ICSU .......... International Council of Scientific Unions (HQs in Paris, France. ICSU

is a non-governmental body created in 1931 to promote international science and its applications. It has a membership of international organizations (Scientific Unions), national science academies and research councils, and Scientific Associates. Some committees of ICSU are: IGBP, SCOPE, SCAR, COSPAR, etc.)

ICWG-EO ...... International Coordination Working Group for Earth Observation IDA ........... Institute of Defense Analysis (since 1957, a DoD nonprofit corpora-

tion) IDEAL ........ International Decade of of East African Lakes (campaign) IDHT .......... Instrument Data Handling and Transmission (ERS-1 S-band antenna) IDN ........... International Directory Network (CEOS-defined for databases, for-

mer designation 'PID') ie ............. abbreviation (Latin: id est) that is IECM . . . . . . . . . . Induced Environment Contamination Monitor (Shuttle) lEE . . . . . . . . . . . Institution of Electrical Engineers (London, UK) IEEE .......... Institute of Electrical and Electronics Engineers (USA) IEF ............ Isoelectric Focusing (Shuttle payload) IEH . . . . . . . . . . . International EUV Hitchhiker (Shuttle payload) IEICE ......... Institute of Electronics, Information and Communication Engineers,

Tokyo, Japan IELV .......... Intermediate Expendable Launch Vehicle (EOS program)

lEOS ......... .

IERS

IERS ......... . I!F ........... . IF ............ . IFAG ......... .

IFARS ........ . IFE ........... . IFEOS ........ .

IFOV ......... . IFREMER .... .


International Earth Observing System (Committee dealing with the policies, principles of data exchange, etc.; partner agencies are: CSA (Canada), ESA (Europe), NASA (USA), and STA (Japan). Delegations from agencies with operational environmental monitoring satellites: NASDA, MITI, JMA (Japan), EUMETSAT (Europe), NOAA (USA), AES (Canada). Typical lEOS missions are: ENVISAT (ESA), EOS/AM-1 (NASA), NOAA-N (NOAA), ADEOS (NASDA), and TRMM (NASA/NASDA). International Earth Rotation Service (Central Bureau in Paris, since 1988) International Earth Reference System Interface Intermediate Frequency Institut fiir Angewandte Geodiisie [Institute of Applied Geodesy - a federal agency under the jurisdiction of the German Ministry of the Interior (BMI) with research in the fields of geodesy, cartography and photogrammetry]. IFAG maintains a central office in Frankfurt/Main and branch offices in Leipzig, Potsdam, and Berlin. Note: In the late 1990s, IFAG was renamed to BKG (Bundesamt fiir Kartographie und Geodiisie. Institute for Applied Remote Sensing (Wedel, Germany) Isoelectric Focusing Experiment (Shuttle payload) International Forum on Earth Observations Using Space Station Elements (since 1986) Instantaneous Field of View Institut Francais de Recherche pour ~Exploration de Ia Mer (French Ocean Agency in Brest, France). IFREMER/CERSAT is a processing and archiving facility for satellite data and is part of the "Departement d'Oceanographie Spatiale" at IFREMER.

IFSAR ......... Interferometric SAR (measurement technique using two antennas, sometimes also referred to as 'InSAR')

IFTI . . . . . . . . . . . Ioffe Physical Technical Institute (St. Petersburg) IGAC .......... International Global Atmosphere Chemistry (IGBP core program) IGAP .......... International Global Programme on Atmospheric Particles IGARSS ....... International Geoscience and Remote Sensing Symposium - since

1981, sponsored by GRSS (Geoscience and Remote Sensing Society) IGBP .......... International Geosphere-Biosphere Programme of ICSU (IGBP is

closely linked, directly or through ICSU, to other international organizations involved in global change research, including: GCOS, IOC, IPCC, ISSC, SCOPE, UNEP, WCRP, WMO. Over 50 countries have national IGBP committees and supporting bodies. The IGBP Secretariat is in Stockholm, Sweden)

IGEB .......... Interagency GPS Executive Board [IGEB (Presidential Decision Directive as of March 1996) offers some formal civil agency participation in the GPS program. It is jointly chaired by the DoD and DoT, with oversight and management of the dual use component of the GPS]

IGEX .......... International GLONASS Experiment, a campaign under the auspices of lAG (International Association of Geodesy)

IGFOV ........ Instantaneous Geometric Field of View IGN ........... Institut Geographique National (French National Geographic Insti-

tute, Paris) IGOS .......... Integrated Global Observing Strategy (for synergetic effects) IGRF .......... International Geomagnetic Reference Field IGS ............ International GPS Service for Geodynamics (since 1993) IGSO .......... Inclined Geosynchronous Orbit IGU ........... International Geographical Union


IGY ........... International Geophysical Year [created in 1952 by the ICSU plenary meeting; the first IGY was planned for 1957/58 (a year of expected maximum solar activity), it coincided also with the start of the space age, the launch Sputnik-1 on Oct. 4, 1957]

IHP ........... International Hydrology Programme (UNESCO) IHO ........... International Hydrographic Organization liP . . . . . . . . . . . . International Ice Patrol IJSSE .......... International Journal of Small Satellite Engineering (electronic jour

nal on internet, edited at the University of Surrey, UK) IKF ............ Institut fiir Kosmosforschung, Berlin-Adlershof, in former East Ger

many. Note: as of Jan. 1992 the IKF was renamed 'Institute of Space Sensor Technology (ISST),' it is part of DLR)

IKI RAN . . . . . . . Space Research Institute (of the Russian Academy of Sciences, RAN (or RAS, depending on the alphabet), Moscow, Russia; extraterrestrial physics and remote sensing, since 1965)

IKI-BAN ....... Space Research Institute, Bulgarian Academy of Sciences (Sofia, Bulgaria)

ILS . . . . . . . . . . . . Instrument Landing System ILS . . . . . . . . . . . . International Launch Services [a joint commercial venture between

Lockheed Martin Corp. (USA), Khrunichev Space Center (KhSC) and RKK Energia (Russia), offering of Atlas and Proton launch systems. The first ILS launch occurred in Sept. 1996 (lnmarsat-3 from Baikonur); since April 15, 1993 all commercial contracts, involving the Proton launch vehicle, are handled by ILS.

IMAGES ....... International Marine Global Change Study (IGBP project) IMAU ......... Institute for Marine and Atmospheric Research Utrecht (University of

Utrecht, The Netherlands) IMAX . . . . . . . . . Image Maximum (a large screen motion picture camera/format used by

the NASNSmithsonian project to document significant space activities)

IMEC .......... Inter-university MicroElectronics Center, Leuven, Belgium. IMEC is a Flemish government initiative to bundle all microelectronics-related efforts of the three scientific universities into one independent nonprofit super-lab.

IMET .......... Improved Meteorological Instrumentation (WHOI buoy type) IMEX ......... Inner Magnetosphere Explorer, a mission ofUMM (University of Min

nesota at Minneapolis) IMF . . . . . . . . . . . Interplanetary Magnetic Field IMK . . . . . . . . . . . Institute fiir Meteorologie und Klimaforschung (Institute for Me

teorology and Climate Research- a cooperative institute ofthe Nuclear Research Center Karlsruhe (KfK) and of the University of Karlsruhe, Germany)

IML ........... International Microgravity Laboratory (Shuttle payload) IMO ........... International Maritime Organization IMP ........... International Monitoring Platform, K.16 IMS . . . . . . . . . . . Information Management System at GSFC (The top-level function of

EOSDAACs) IMTA .......... Instituto Mexicano de Tecnologica del Agua (Cuernavaca, Mexico) IMU ........... Inertial Measurement Unit (navigation instrument on aircraft) INCA .......... Indian National Cartographic Association INDEX ........ Indian Ocean Experiment (campaign) INDEX ........ Innovative Technology Demonstration Experiment (of ISAS, Japan) INDOEX ....... Indian Ocean Experiment (campaign) INDREX ....... Indonesian Radar Experiment (campaign) INFN .......... Istituto Nazionale Fisica Nucleare (Italian National Institute of Nu

clear Physics), Rome, Italy lNG ........... Istituto Nazionale di Geofisica (Rome Italy)


InAs . . . . . . . . . . . Indium Arsenide (detector type for IR spectrum) InGaAs . . . . . . . . Indium Gallium Arsenide (a detector type for IR spectrum) InGaP/GaAs .... Indium Gallium Phosphorus/Gallium Arsenide (solar cell type) INM ........... Instituto Nacional de Meteorologica (Spanish Weather Service) Inmarsat ....... International Maritime Satellite Organization (London, UK) InP ............ Indium Phosphide (solar cell type) INPE .......... Instituto de Pesquisas Espaciais (National Institute of Space Research,

Sao Jose dos Campos, S.P., Brazil, since 1971) IN QUA ........ International Union for Quaternary Research (of ICSU) INR ........... Image Navigation and Registration (GOES Second Generation SIC) INRA .......... Institut National de Ia Recherche Agronomique (Grignon and Montfa

vet, France) In-RIMT ....... Indian Resources Information and Management Technologies Pvt.

Ltd, Hyderabad, India INS ............ Inertial Navigation System (for aircraft navigation) INS ............ Institute of Nuclear Physics, (New Zealand) INSA . . . . . . . . . . Ingenieria y Servicios Aeroespaciales, Madrid, Spain (Fuego mission

coordinator) INSAT ......... Indian National Satellite (series, employed for meteorology and com-

munication), F.6 IN-STEP ....... In-Space Technology Experiments Program (NASA) INSU .......... Institut National des Sciences de l'Univers (Paris, part of CNRS) InSb . . . . . . . . . . . Indium antimonide (detector type material for infrared region) INTA .......... Instituto National de Tecnica Aeroespacial (Space Agency of Spain) Intelsat . . . . . . . . . International Telecommunications Satellite Organization (Washing-

ton, DC) INTERBALL . . . IKI mission program (solar-terrestrial interaction) within ISTP, K.17 Intercosmos . . . . . USSR/CIS space program for collaborative science projects among its

nine members and with other nations. Intercosmos was created in 1967 inviting the former Soviet-affiliated countries (like, East-Germany, Hungary, Bulgaria, Poland, etc.) to participate in the Soviet space program with their own national contributions (one area of participation was in remote sensing, building sensors for specific missions, dissemination and scientific interpretation of data, etc. ). Activities in international manned space flight missions were also under the label of Intercosmos. Satellites in the Intercosmos program are named 'Intercosmos-n', like Intercosmos-19 (launched Feb. 27, 1979).

IOC ........... Initial Operating Capability (GPS, GLONASS,) IOC ........... Intergovernmental Oceanographic Commission (of UNESCO) IOCM ......... Interim Operational Contamination Monitor (Shuttle payload) ION ........... Institute of Navigation (Washington, DC, since 1945) lOP ........... Intensive Observation Period (within a campaign) lOS ............ Institute for Ocean Sciences (Sydney, British Columbia, Canada) lOW ........... Institut fiir Ostseeforschung Warnemiinde (Institute for Baltic Sea Re

search, Warnemiinde, Germany) IPCC .......... Inter-Governmental Panel for Climate Change (set up by WMO and

UNEP in 1988) lPG ........... Institute of Applied Geophysics (Moscow, Russia) lPG-Paris ....... Institut de Physique du Globe de Paris IPMP .......... Investigations into Polymer Membrane Processing (Shuttle experi

ment) IPO ........... Integrated Program Office (Silver Spring, MD), consisting of a team

made up of NOAA, NASA and DoD representatives for the development of the NPOESS spacecraft series

IPOMS ........ International Polar-Orbiting Meteorological Satellite IPS ............ Instrument Pointing System (Spacelab-2, built by ESA, structure for

mounting telescopes)


IPS . . . . . . . . . . . . Ion Propulsion System IRCFE . . . . . . . . . Infrared Communications Flight Experiment (Shuttle) IR&D . . . . . . . . . Independent Research & Development (company internal funding) IRD . . . . . . . . . . . Institut de Recherche pour le Developpement (Paris, France, successor

organization to ORSTOM) IRE RAN . . . . . . Institute of Radioengineering and Electronics (of the Russian Acade

my of Sciences, RAN, in Moscow; founded in 1953, IRE is involved in remote sensing, etc., also providing general management services)

IRF . . . . . . . . . . . Swedish Institute of Space Physics [ (Institutet fi:ir rymdfysik ), a governmental research institute with the following divisions: IRF-K (Kiruna), IRF-Um (Umea) with a Laboratory of Mechanical Waves and a Space Physics Group at Umea University, IRF-U (Upsalla), IRF-STL (Solar Terrestrial Physics) Lund Division]

IR-IE .......... Infrared Imaging Experiment (Shuttle payload) IRIS ........... International Radio Interferometric Surveying (Subcommittee of the

International Association of Geodesy) IRIS ........... Italian Research Interim Stage (upper stage used in conjunction with

NASA's Shuttle to place payloads up to 900 kg into geo-transfer orbit) IRLS .......... Interrogation, Recording and Location Subsystem (French-US Eole

experiment flown on Nimbus-3 in 1969) IRM . . . . . . . . . . . Ion Release Module (SIC of the AMPTE mission, K.4.1) IRMB . . . . . . . . . Institut Royal de Meteorologie Belgique (Royal Meteorological Insti

tute of Belgium, Brussels) also referred to as KMI!IRM IROE - CNR .... Istituto Ricerca Onde Elettromagnetiche - Consiglio Nazionale delle

Ricerche (Florence, Italy) IRS . . . . . . . . . . . . Information Retrieval System (ESA data system) IRS ............ Indian Remote Sensing Satellites (ISRO), D.17 (IRS-1A, lB, 1C, lD,

1E, etc.) IRS . . . . . . . . . . . . Inertial Reference System IRS ............ Institut fiir Raumflugsysteme (University of Stuttgart, Germany) IRSA . . . . . . . . . . Institute for Remote Sensing Applications ( ofJRC, Ispra, Italy. In 1996

IRSA was renamed to SAl = Space Applications Institute) IRSA .......... Institute for Remote Sensing Applications, since 1980 (Beijing, Chi

nese Academy of Sciences) IRSC .......... Iranian Remote Seeing Center, Tehran, Iran (funded by the Ministry of

Posts and Telecommunications) IRT ............ Infrared Telescope (Spacelab-2 instrument, a 15 em fl4 Herschelian

telescope) IRU ........... Inertial Reference Unit ISA ............ Institute of Space Aeronomy (Brussels, Belgium) ISA ............ Israel Space Agency (since 1983 -within theframework of the Ministry

of Science and Technology) ISAC .......... Intelsat Solar Array Coupon (Shuttle experiment) ISAC .......... ISRO Satellite Center (Bangalore, India) ISAIAH ........ Israeli Space Agency Investigation about Hornets (Shuttle experi

ment) ISAL . . . . . . . . . . Investigation of STS Atmospheric Luminosities (Shuttle) ISAS ........... Institute for Space and Astronomical Science (University of Tokyo, Ja

pan) ISCCP ......... International Satellite Cloud Climatology Project (by ICSU & WMO) ISDE (RNII KP) Institute of Space Device Engineering, Moscow; a leading Russian

company in the design and development of sensors; participation in programs: Venera, Vega, Phobos, Luna, Mars, Prognoz, Granat, Resurs, Okean, Glonass, etc.

ISDE .......... International Symposium on Digital Earth ISDN .......... Integrated Services Digital Network ISEE .......... International Sun Earth Explorer (3 SIC mission), K.18


ISIR . . . . . . . . . . . Infrared Spectral Imaging Radiometer (Shuttle payload) ISIS ........... Intelligent Satellite-Data Information System (a DLR/DFD archival

system and service) ISLR . . . . . . . . . . Integrated Side Lobe Ratio ISLSCP ........ International Satellite Land-Surface Climatology Project (by ICSU

and WMO) ISN ............ Institute of Satellite Navigation at the University of Leeds, UK ISO . . . . . . . . . . . . International Standards Organization (one of three bodies responsible

for the definition of OSI) ISOPS ......... International Space Conference of Pacific-Basin Societies ISRO .......... Indian Space Research Organization (HQ at Bangalore, since 1969) ISRO/IISU ..... ISRO Intertial Systems Unit ISRO/ISAC ..... ISRO Satellite Center (Bangalore, India) ISRO/ISTRAC .. ISRO Telemetry, Tracking and Command Network ISRO!LPSC .... ISRO Liquid Propulsion Systems Center ISRO/MCF ..... ISRO INSAT Master Control Facility ISRO/SAC ...... ISRO Space Applications Center (Ahmedabad, India) ISRO/SHAR .... ISRO Sriharikota Range (ISRO launch site, East Coast of India) ISRONSSC .... ISRO Vikaram Sarabhai Space Center (launch vehicle development) ISPRS ......... International Society for Photogrammetry and Remote Sensing ISPR .......... International Standard P~load Rack (adopted by the ISS program),

each ISPR provides 1.6 m of space, the rack has a mass of 104 kg and can accommodate up to 700 kg of payload mass

ISS ............ International Space Station ISSC ........... International Social Science Council (UN) ISSI . . . . . . . . . . . International Space Science Institute, Bern, Switzerland 1ST ............ Instrument Support Terminal (EOSDIS Facility) ISTP ........... International Solar-Terrestrial Physics Program [involves a total of 12

satellites provided by ESA (SOHO, CLUSTER), NASA [GGS (POLAR, WIND), IMP-8, FAST], IKI (Interball, ECOS-A), ISAS (Geotail)]

ISTRAC ISRO Telemetry and Command Center (Bangalore, India) ISTS ........... Institute for Space and Terrestrial Science (North York, Ontario, Cana

da) Note: A name change to CREST ( Centerfor Research in Earth and Space Technology) took place on Sept. 24, 1997

ISTS ........... Institute of Space and Astronautical Science (Tokyo, Japan) ISY ............ International Space Year (1992) ITAR . . . . . . . . . . International Traffic in Arms Regulation (US regulations related to the

export of satellite and rocket technology) ITCZ . . . . . . . . . . Inter Tropical Convergion Zone ITEX .......... Island Thunderstorm Experiment (campaign) ITIR2110) ....... Intermediate Thermal Infrared Radiation (EOS sensor); ITIR was re

named in 1990 ASTER = Advanced Spaceborne Thermal Emission and Reflection Radiometer

ITO . . . . . . . . . . . Indium Tin Oxide (a light sensitive sensor type) ITOS .......... Improved TIROS Operational System (NOAA SIC) ITRF . . . . . . . . . . International Terrestrial Reference Frame (established by IERS) ITT NCD ...... ITT (international Telephone and Telegraph Corporation) Aerospace/

Communications Division (Fort Wayne, IN), builder of remote sensing instruments (AVHRR, HIRS, GOES-senes instruments, etc.). The parent company is ITT Industries Inc., headquartered in New York, NY.

ITU ........... International Telecommunication Union (since 1865 founded as International Telegraphy Union, since 1934 as ITU, since 1947 ITU is a UN agency to cover standards for a wide range of telecommunication ser-

2110)"The Earth Observer," Vol. 2 No. 10, Dec. 1990, pp. 3

1436

ITU-R

ITU-T ......... . IUGG ........ . IVHM ........ .

IVHS ......... . IWF .......... . IZMIRAN ..... .


vices, including frequency allocations standards for fax, ISDN, JPEG, MPEG, ATM, etc., Geneva, Switzerland) ITU-Radiocommunication standardization sector (formerly known as CCIR - responsible for managing efficient use of the radio-frequency spectrum) ITU-Telecommunication standardization sector (formerly CCITT) International Union of Geodesy and Geophysics (a union of ICSU) Integrated Vehicle Health Monitoring (Shuttle payload, terchnology demonstration) Intelligent Vehicle/Highway Systems Institut fiir Weltraumforschung, Graz, Austria Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation (of Russian Academy of Sciences, Troitsk, Moscow region)

J JAMSTEC ...... Japan Marine Science and Technology Center (Tokyo) JAROS ........ Japan Resources Observation System Organization JAFIC ......... Japan Fisheries Information Center JCAB .......... Japanese Civil Aviation Bureau (JCAB is an agency/organization with

in the Japanese Ministry of Transport) JEA ........... Japan Environmental Agency JEM ........... Japanese Experiment Module (Japan's pressurized module directly at-

tached to the Space Station Freedom) JEM-EF ........ JEM-Extemal Facility JEOS .......... Japanese Earth Observation System JERS .......... Japanese Earth Resources Satellite, D.18 JFET .......... Junction Field-Effect Transistor JGOFS ......... Joint Global Ocean Flux Study (IGBP program) JGR ........... Journal of Geophysical Research (a publication of AGU) JGPSC ......... Japan GPS Council (over 80 manufacturers, major users, research

institutes, etc.) JHU ........... Johns Hopkins University (Baltimore, MD, USA) JHU/APL ...... JHU/Applied Physics Laboratory, Laurel, MD, USA, since 1942; APL

is a major space research institute (staff of 2700) and the designer and builder of satellites (Transit series, ACE, AMPTE/CCE, MSX, NEAR, TIMED, etc.), instruments, SIC engineering, technical innovations, etc.

JMA ........... Japan Meteorological Agency (JMA is an agency/organization within the Japanese Ministry of Transport)

JODC ......... Japan Oceanographic Data Center JOWIP ......... Joint Canada-US Ocean Wave Investigation Project (campaign) JPEG .......... Joint Photographic Experts Group (a compressed image format stan

dard, 24-bit color; note: JPEG is a lossy compression technique based onDCT)

JPEG-LS ....... JPEG lossless- use of a 2-D edge-detection predictor. JPEG-LS is the new (1998/9) lossless/near-lossless compression standard for continuous-tone images, IS0-14495-l/ITU-T.87. The standard is based on the LOCO-I algorithm (LOw COmplexity LOssless COmpression for Images) developed at Hewlett-Packard Laboratories.

JPL ............ Jet Propulsion Laboratory, Pasadena, CA, since 1944 (DAAC of NASA EOS Program). JPL is the only NASA center that is managed by a university, namely the California Institute of Technology

JPO ........... Joint Program Office (GPS) JPOP .......... Japanese Polar Platform JRC ........... Joint Research Centre (umbrella agency of CEU coordinating eight re

search institutes at five sites (Gee!, Belgium; Karlsruhe, Germany; Petten, Netherlands; Ispra, Italy; Seville, Spain). IRMM (Institute for Ref-


erence Materials and Measurements) is located in Gee!; ITU (Institute of Transuranium Elements) is in Karlsruhe; lAM (Institute of Advanced Materials) is in Petten; IPS (Institute for Prospective Technological Studies) in Seville. The following institutes are located in Ispra: ISIS (Institute for Systems, Informatics and Safety), EI (Environment Institute), SAl (Space Applications Institute), IHCP (Institute for Health and Consumer Protection).- The JRC Program Directorate is located in Brussels.

JSC ............ Johnson Space Center (Houston, TX, USA) JSC ............ Joint Scientific Committee (of WCRP) JST ............ Japan Science and Technology Corporation (Tokyo. a Japanese govern

ment corporation promoting new technologies and basic research) JUSREX ....... Joint US/Russian Internal Wave Remote Sensing Experiment (cam

paign) JWGA ......... Joint Working Group ATMOS

K

KACST ........ King Abdulaziz City for Science and Technology (Riyadh, Saudi Arabia, since 1977), home of SRISA (Space Research Institute of Saudi Arabia)

KAIST . . . . . . . . . Korean Advanced Institute of Science and Technology (Seoul, Korea, since 1981)

KAIST/SaTReC . KAIST/ Satellite Technology Research Center (Taejon, Korea, since 1989, SaTReC is a university based research center)

KARl .......... Korea Aerospace Research Institute (Taejon, Korea, since 1989) KAO ........... Kuiper Airborne Observatory (C-141 aircraft of NASNARC) KAPEX . . . . . . . . Cape of Good Hope Experiments (campaign) KARl . . . . . . . . . . Korea Aerospace Research Institute, Taejon, Korea KACST . . . . . . . . King Abdulaziz City for Science & Technology, Riyadh, Saudi Arabia KEOC . . . . . . . . . Korean Earth Observation Center, Seoul, Korea KfA ........... Kernforschungsanlage Jiilich (Nuclear Research Center, Jiilich, Ger

many) KfK ........... Kernforschungszentrum Karlsruhe (Nuclear Research Center, Karls

ruhe, Germany; KfK was renamed to FZK (Forschungszentrum Karlsruhe as of 1995)

KFKI .......... Hungarian Research Institute for Particle and Nuclear Physics KH . . . . . . . . . . . . Keyhole (a code name designating a DoD reconnaissance satellite se

ries as well as the principal camera system of the S/C) KhSC . . . . . . . . . . Khrunichev State Research and Production Space Center, Moscow KidSat ......... A NASA-sponsored program (start in 1995, the first Shuttle flight of

Kidsat was on STS-76 in March 1996) to encourage the student and educator community in space technology involvement, to bring space exploration into the classrooms. Activities may encounter interpretation of remotely-sensed images, the development of imaging instruments as well as their on-orbit operation. Further Shuttle flights of KidSat on STS-81 (Jan.12-22, 1997) and on STS-86 (Sept. 25- Oct. 6, 1997). Access to the program is via Internet. KidSat observation missions are carried out on Space Shuttle flights and on the future Space Station.

KITSAT ........ Korea Institute of Technology Satellite (D.19, D.40.6, D.40.10,) KNMI ......... Koninklijk Nederlands Meteorologisch Instituut (Royal Netherlands

Meteorological Institute) De Bilt, Netherlands KOMPSAT ..... Korea Multi-Purpose Satellite, D.20 KSC ........... Kennedy Space Center (NASA facility at Cape Canaveral, FL, USA) KTH ........... Kung! Tekniska Hi:igskolan (Royal Institute ofTechnology) Stockholm,

Sweden


L

L3 ............. Latitude/Longitude Locator (Shuttle experiment) LAAS .......... Local Area Augmentation System (GPS). LAAS is FAA's ground

based augmentation system for local area DGPS. LAB EN S.p.A. .. Laboratori Elettronici Nucleari, of Vimodrone (Milano, Italy), Lab of

Alenia Spazio (a Finmeccanica company). LABEN was founded in 1958, it produces electronic systems, transducers, LAGRANGE (LABEN GNSS Receiver for Advanced Navigation), etc.

LAC ........... Local Area Coverage (NOAA downlink mode) LacrosseNega . . . A DoD/NRO radar imaging satellite reconnaissance program. La

crosse-1 was launched Dec. 2, 1988 by Shuttle (STS-27) and went into a 57° orbit with an altitude of 680 km. Lacrosse-2 was launched from VAFB on March 8, 1991. Lacrosse-3 was launched from VAFB on Oct. 24, 1997. Lacrosse-4 was launched from VAFB on May 22, 1999.

LADAR . . . . . . . . Laser Detection and Ranging LAEFF . . . . . . . . Laboratorio de Astrofisica Espacial Fisica Fundamental (Villafranca,

Spain, Laboratory for Space Astrophysics and Theoretical Physics, since 1990)

LAGEOS-1,11 ... Laser Geodynamics Satellite (NASNASI), E.15 LAMBADA . . . . Large-scale Atmospheric Moisture Balance of Amazonia using Data

Assimilation (campaign) LAN ........... Local Area Network LandSat ........ Land (Remote Sensing) Satellite, US EO program, D.21 LANL ......... Los Alamos National Laboratory (Los Alamos NM, DOE facility, op

erated by the University of California). Builder of satellites (ALEXIS, FORTE, MTI, etc) and instruments for space research (solar wind, lightning detection). Los Alamos played (and plays) a key role in monitoring treaty compliance with satellite sensors (detecting atmospheric nuclear tests).

LAPAN ........ Lembaga Penerbangan dan Antariksa Nasional (Indonesian National Institute of Aeronautics and Space, Jakarta)

LAP-B ......... Link Access Protocol (forB Channels) LaRC .......... Langley Research Center (Hampton VA, DAAC of NASA EOS Pro

gram) LASP .......... Laboratory for Atmospheric and Space Physics at the University of

Colorado, Boulder, CO LASER ........ Light Amplification by Stimulated Emission of Radiation LASSO ........ Laser Synchronization from (Geo)Stationary Orbit (ESA, Meteosat) LAT ........... Laboratoire d'Astrophysique de Toulouse (France) Lavochkin . . . . . . Lavochkina Scientific Production Association, Khimky, Russia LBH ........... Lyman-Birge-Hopefield (spectral bands in the 140-180 nm range) LCD ........... Liquid Crystal Display (a device acting as a valve through which polar-

ized light passes unless blocked by the application of a low voltage) LDCE . . . . . . . . . Limited Duration Space Environment Candidate Materials Exposure

(Shuttle experiment) LDCM ......... Landsat Data Continuity Mission (of NASA, an LDCM launch is con

sidered for the 2005/6 time frame) LDEF ......... Long Duration Exposure Facility, NASA SIC, J.8 LDEO ......... Lamont-Doherty Earth Observatory (Columbia University, New York,

NY, USA, since 1949) LDR ........... Linear Depolarization Ratio LEADEX ...... Arctic Leads Experiment (campaign) LED ........... Light-Emitting Diode (a semiconductor device which becomes lumi

nescent on application of a low voltage) LEDA ......... Landsat On-Line Earthnet Data Availability (ESA database file) LEED ......... Low-Energy Electron Diffraction


LEGOS . . . . . . . . Laboratoire d'Etudes en Geophysique et Oceanographie Spatiale (Toulouse, France, affiliated with CNES, CNRS and the Universite Paul Sabatier in Toulouse; research in geophysics, oceanography and glaciology)

LEO ........... Low Earth Orbit (usually for all satellite orbits up to 1000 or 2000 km altitude; in contrast to geostationary (GEO) orbits at altitudes of about 36000 km)

LEOP .......... Launch and Early Orbit Phase LeRC .......... NASA Lewis Research Center (Cleveland, OH, USA). Note: On

March 1, 1999, LeRCwas renamed to NASA's John H. Glenn Research Center (GRC) at Lewis Field, OH.

LERTS ......... Laboratoire d'Etudes et de Recherches en Teledetection Spatiale (Toulouse, France, belongs to CNESICNRS, renamed to CESBIO as of 1995)

LES ........... Lincoln (Laboratory) Experimental Satellite. A DoD microsatellite series (up to LES-4) and minisatellite series (LES-S to LES-9) designed and built at MIT ILL (test of communication technologies). Launch of LES-1 on Feb. 11, 1965; launch of LES-9 on March 15, 1976

LETI .......... Laboratoire d'Electronique de Technologie et d'Instrumentation (at Grenoble, France)

LEWEX ....... Labrador Extreme Wave Experiment (campaign) LF ............ Low Frequency (30 -300kHz band) LFC ........... Large Format Camera, 1.9 LFSAH . . . . . . . . Light Weight Flexible Solar Array Hinge (Shuttle payload) LHCP ......... Left Hand Circural Polarization LHP ........... Loop Heat Pipe (Shuttle Experiment) LH Systems ..... LH Systems LLC, with company HQ in San Diego, CA (airborne cam

eras). In 1997, Leica AG of Heerbrugg (photogrammetry and aerial camera systems), Switzerland, formed a joint venture with BAE SYSTEMS, Inc. of San Diego, CA, and with Helava Associates Inc. a subsidiary ofGDE Systems. The new company is called "LH Systems LLC" in San Diego and LH Systems GmbH in Heerbrugg, Switzerland

Li-Ion (or LI) Lithium-Ion (battery type) LIDAR . . . . . . . . Light Detection and Ranging LIF ............ Laser-Induced Fluorescence (active remote sensing method) LIGA .......... Llthographie, Galvanoformung und Abformung (lithography, electro-

plating and moulding) LIGO .......... Laser Interferometric Gravitational-wave Observatory LIMEX ........ Labrador Ice Margin Experiment (campaign) LISA . . . . . . . . . . Laser Interferometer Space Antenna (a three SIC mission of NASA,

ESA, etc., proposed for 2005 and beyond). The objective is to study lowfrequency gravitational waves from galactic and extra-galactic binary systems. The three SIC are separated some 5,000,000 km apart, forming an equilateral triangle (a giant interferometer).

LISS ........... Linear Imaging Self-Scanning Sensor (ISRO sensor series) LITE .......... Lidar In-space Technology Experiment, Shuttle mission, J.lO LLNL .......... Lawrence Livermore National Laboratory (Livermore, CA, a DOE lab

managed by the University of California) LLV1 (or 2) ..... Lockheed Launch Vehicle 1 (or 2) LM ............ Lockheed Martin Corporation, HQ at Bethesda, MD. The world's larg

est space company resulted in 1995 as a merger of the former Lockheed Missiles and Space Co. with the former Martin Marietta Astronautics and Martin Marietta Astro Space (which itself is based on former GE Astro Space). The new LM structure has five sectors, each with operating units and subsidiaries. The sectors are: Aeronautics, Electronics, Energy, Information & Services, and Space & Strategic Missiles. LMMS (see below), LM Astronautics (Denver, CO), LM Telecommu-


nications (Sunnyvale, CA) are units of the Space & Strategic Missiles sector. Total LM employment is about 170,000.

LMD . . . . . . . . . . Laboratoire de Meteorologie Dynamique, Palaiseau (Lab of CNRS) LMI . . . . . . . . . . . Lockheed Martin Intersputnik, a joint venture company (since 1997) of

Lockheed Martin Corporation and the Intersputnik International Organization of Space Communications

LMLV ......... Lockheed Martin Launch Vehicle [after its first successful flight, Aug. 23, 1997 (Lewis S/C), LMLV was renamed to Athena the Greek goddess of wisdom)]

LMMS ......... Lockheed Martin Missile & Space Company (HQ at Sunnyvale, CA). LMMS is a major builder of satellites and sensors for civil (TIROS, AM-1, ISS, HST, Gravity Probe-B, Wind, Polar, Landsat-?, TRACE, etc.) and military (DMSP, GPS, etc.) US space programs as well as for commercial Earth observation programs (CRSS, etc.). LMMS has a workforce of about 19,000 employees and maintains facilities at the following locations: Huntsville, AL; Cape Canaveral, FL; Kings Bay, GA; East Windsor, NJ; Valley Forge, PA; Charleston, SC; Magna, UT; Bangor, WA; and Sunnyvale, Santa Cruz, Palo Alto and VAFB, all in CA. LMMS is also the manufacturer of the following standard platform series (communication satellite buses): S3000, S4000, SSOOO, S7000, and A2100; and the manufacturer of Motorola's Iridium system.

LMS ........... Life and Microgravity Spacelab (Shuttle mission) LNA ........... Low Noise Amplifier LNETI ......... Laboratorio Nacional de Engenhario e Technologia Industrial (PoSAT

consortium, Portugal) LO . . . . . . . . . . . . Local Oscillator LOA ........... Laboratoire d'Optique Atmospherique, (of CNRS, at the University of

Sciences and Technology, Lille, France) LOICZ ......... Land-Ocean Interactions in the Coastal Zone (core program ofiGBP) LORAN ........ Long Range Aid to Navigation (a radionavigation system as well as an

instrument name). LORAN-C operates on 100kHz and is a maritime and aeronautical radionavigation system.

LOS . . . . . . . . . . . Loss of Signal LOS . . . . . . . . . . . Line of Sight LOTREX ...... Landoberflachen-Traversen Experiment (campaign) LOWS ......... Lake Ontario Winter Storms (campaign) LOWTRAN .... LOW-resolution TRANsmittance a computer code (model of USAF

Geophysics Laboratory), see Glossary. LPCE .......... Laboratoire de Physique et de Chimie de !'Environment (CNRS), Or

leans, France LPCM ......... Laboratoire de Physique et Chimie Marines (CNRS), Villefranche

sur-mer, France LRPT .......... Low Resolution Picture Transmission (NOAA downlink technique in

S-band) LS ............. Landsat Satellite Series of NOAA LSPIM ......... Land Surface Processes and Interactions Mission (in ESA's Earth Ex-

plorer Program), see SPECTRA LST . . . . . . . . . . . Land Surface Temperature LTAN .......... Local Time Ascending Node (orbit parameter) LTER .......... Long-Term Ecological Research (NFS program that started in 1981,

there are 19 major sites within LTER spread throughout the US) LTS ........... Low Temperature Superconductivity (refers to conductor material lev-

els at liquid helium temperatures, Tc = 4 K) LUCC ......... Land-Use/Cover Change (IGBP program) LUT ........... Local User Terminal (NOAA concept for S&R reception) LWIR .......... Long-Wavelength Infrared (6-14 !!ill) same range asTIR


M MAB .......... Man and Biosphere Programme (UNESCO, since 1989) MABL . . . . . . . . . Marine Atmospheric Boundary Layer MAC .......... Multiphase Atmospheric Chemistry (IGBPIIGAC program) MACE . . . . . . . . . Middeck Active Control Experiment (of NASA and AFRL on Shuttle).

MACE and MACE-II (AFRL) are designed to to investigate modeling and control issues (high precision pointing and vibration control)

MAC-Europe ... Multisensor Airborne Campaign -Europe MACSI ........ Microwave Airborne Campaign over Snow and Ice (campaign) MAESA ........ Measurement for Assessing the Effects of Stratospheric Aircraft (cam

paign) MAESTRO ..... Multiple Airborne Experiments Towards Radar Observations (cam

paign) MAGE ......... Marine Aerosol and Gas Experiment (campaign) Magnolia/MFE .. (MFE = Magnetic Field Experiment) A joint French/US program

(proposal status) for long-term (>5 years) monitoring of the Earth's magnetic field and its temporal variations (objectives: main field model, secular variations, core motion determination, electrical conductivity of the mantle)

MAGS . . . . . . . . . Mackenzie River GEWEX Study (campaign) MAHLOVS .... Middle and High-Latitude Oceanic Variability Study MAMA ........ Multi-Anode Michrochannel Array (detector type) MAP . . . . . . . . . . Mesoscale Alpine Programme (campaign) MAP .......... Microwave Anisotropy Probe (NASA SIC mission within the MID EX

program, measurement of the full sky cosmic microwave radiation) MAPS . . . . . . . . . Measurement of Air Pollution from Space Radiometer (Shuttle

OSTA-1 experiment during STS-2 in Nov. 1981, and STS-59), 1.11 MASER . . . . . . . . Microwave Amplification by Stimulated Emission of Radiation MAST . . . . . . . . . Military Application of Ship Tracks (Shuttle) MAST ......... Monterey Area Ship Tracks (campaign) MAST ......... Marine Science and Technology (campaign) MASTEX ...... Mediterranean Aircraft-Ship Transmission Experiment (campaign) MAUS . . . . . . . . . Material Science Autonomous Payload (Shuttle D2 mission) MBA . . . . . . . . . . Microbolometer Array (detector type) MBARI . . . . . . . . Monterey Bay Aquarium Research Institute, Monterey, CA MBB .......... Messerschmitt Bolkow & Blohm (Munich, Germany, since 1989 MBB

was integrated into the DASA conglamorate) MBE . . . . . . . . . . Molecular Beam Epitaxy [a technique (developed by Bell Labs in 1968)

to grow perfect crystals, atom by atom, over areas vast on an atomic scale. Applications: the production of photodiode arrays, quantum wells, heterojunction structures, etc.]

MCC .......... Mission Control Center MCHIP/s ....... CHIP stands for Yes/No sequences in data transmissions. One

MCHIP/s = 1 million information sequences/s MCP .......... Meteorological Communications Package (Meteosat). MCP permits

direct data access to the operational meteorological instruments in full resolution during a pass. MCP allows in addition the transmission of global data sets for central ground stations.

MCP .......... Microchannel Plate (detector) MCSA ......... MIR Cooperative Solar Array (installation on MIR by STS-74 crew) MCT .......... Mercury Cadmium Telluride (detector material, HgCdTe, also referred

to as HCT detector) MCTEX ....... Marine-Continental Thunderstorm Experiment (campaign) MDA . . . . . . . . . . MacDonald Dettwiler Associates Ltd, Richmond, BC, Canada (MDA

is a developer of SAR processors, builder and operator of Radarsat -2) MDL .......... Multi-use Data Link (GOES Second Generation SIC) MDT . . . . . . . . . . Mean Down Time

1442 Appendix B: Acronyms and Abbreviations --------------------

MEDALUS ..... Mediterranean Desertification and Land Use (campaign) MEDEA ....... Material Science Experiment Double Rack for Experiment Modules

and Apparatus (Shuttle experiment) MEDS ......... Marine Environmental Data Service (Ottawa, Ontario, Canada) MEEP ......... MIR Environmental Effects Payload (Shuttle payload) MEG .......... Magneto-Encephalography (medical X-ray imagery) MEl ........... Moscow State Aviation Institute (Department of Spacecraft Electric

Propulsion and Power Plants) MELCO ....... Mitsubishi Electric Company, Tokyo, Japan MELEO ....... Materials Exposure in Low Earth Orbit (Shuttle experiment) MELV ......... Medium Expendable Launch Vehicle (EOS program) MEMS ......... Micro-Electromechanical System (sensor technology), also Shuttle

payload MEO .......... Medium Earth Orbit (altitude range of about 5000-25000 km) MFD .......... Manipulator Flight Demonstration (Shuttle payload, JEM flight

demo) Megha-Tropiques A CNES/ISRO minisatellite EO mission considered for launch in 2005.

Note: Megha is the Hindi word for clouds. MEPhi . . . . . . . . . Moscow Engineering Physics Institute MERIT ........ Measure Earth Rotation and Intercompare the Techniques (an In-

ternational Earth Rotation Service Program) Meteo-France ... Meteorological agency of France (Toulouse, Brest, etc.) METEOR ...... Russian meteorological satellite family, G.4 - G.S METEOSAT .... European meteorological satellite series of EUMETSAT, F.7 METOC ....... Meterology & Oceanography [a US Navy program considering every

thing from weather observation (instruments), operations of the system, GIS services, to oceanography applications and the combination of both functions]

MetOp ......... EUMETSAT Meteorological Operational satellite series, G.2.1 MeV ........... Mega-electron volt MF ............ Medium Frequency (300- 3000kHz band) MFLOPS ....... Million Floating Point Operations per Second (a measure of computer

power) · MGBX ......... Microgravity Glovebox Facility (Shuttle payload) MGM .......... Mechanics of Granular Materials (Shuttle payload) MHS .......... Message Handling System (MOTIS is the ISO definition of MHS) MHT .......... Matra Hautes Technologies, France, (MHT's parent company is the

Ladardere Groupe; Matra Marconi Space (MMS) is a unit of MHT) Microlab ....... OSC satellite renamed to OrbView-1, B.8.1 MID EX ........ Medium-class Explorers (NASA program). A series of cost and sched

ule-capped programs, led by a PI and funded by NASA. MIGITS ........ Miniature Integrated GPS/INS Tactical System (a familiy of GPS-re

lated receiver systems of Boeing Co.) MILOX ........ Mid-Latitude Ecosystems and Photochemical Oxidants (IGBP/IGAC) MIL-STD-1553B A spacecraft communications bus standard. The structure of the bus

consists of a single bus controller connected to remote terminals (up to 31 max can be used).

MILS TAR . . . . . . Military Strategic and Tactical Relay (heritage of STP). MILS TAR is a series of advanced US military (DoD) communication satellites. The first two Block 1 spacecraft, launched in 1995, will eventually be replaced by the Block 2 Milstar 3 through 6, which are scheduled for launch beginning in 1999.

Minotaur ....... An OSC (Dulles, VA) launch vehicle. The Minotaur is a four-stagevehicle with the first and second stages being Minuteman-II stages; the two upper stages come from OSC's Pegasus launcher. OSC's Minotaur is also known as the "Orbital/Suborbital Program Space Launch Vehicle." The US Air Force developed the Orbital/Suborbital Program as


a way to cheaply launch small military payloads. OSC integrates the Minotaur launch vehicles and conducts launch operations under an Air Force contract.

MIR . . . . . . . . . . . Russian Space Station, L.3 MIRAS ........ MIR Infrared Spectrometer (note: this is a modified GRILLE sensor

by ISA on the Shuttle ATLAS-1 mission) MIRSL ........ Microwave Remote Sensing Laboratory (U. of Massachusetts at Am-

herst, MA) MIRP .......... Manipulated Information Rate Processor (NOAA SIC subsystem) MIS-1, -B ....... Microcapsules in Space-1 (Shuttle experiment) MIST .......... Microbursts and Severe Thunderstorms (campaign) MISU .......... Meteorological Institute of Stockholm University (Stockholm, Swe-

den) MIT ........... Massachusetts Institute of Technology (Cambridge, MA) MIT/ERL ...... MIT/Earth Resources Laboratory (Cambridge, MA, since 1982) MIT/LL ........ MIT/Lincoln Laboratory (Lexington, MA, since 1951) MITA .......... Microsatellite Italiano a Tecnologia Avanza (Italian Advanced Micro-

satellite platform), ASI standard platform MITI .......... Ministry of International Trade and Industry (Japan) MIZ . . . . . . . . . . . Marginal Ice Zone MIZEX ........ Marginal Ice Zone Experiment (campaign) MLE .......... Mesoscale Lightning Experiment (Shuttle payload) MLML ......... Marine Light-Mixed Layers (campaign program and a moored site) MLOPEX ...... Mauna Loa Observatory Photochemistry Experiment (campaign) MLR .......... Monodisperse Latex Reactor (Shuttle experiment) MLS ........... Microwave Landing System (cancelled by FAA in 1994) MLTI .......... Mesosphere and Lower-Thermosphere/Ionosphere (altitude from

about 60 to 180 km) MMA . . . . . . . . . . Microgravity Measurement Assembly (ESA payload on Shuttle) MMIC ......... Microwave Monolithic Integrated Circuit (also: Millimeter-wave

Monolithic Integrated Circuit) MMS .......... Magnetospheric Multi-Scale (planned misson of NASA) MMS .......... Matra Marconi Space [of France (HQ at Velizy, and major assembly

plant at Toulouse) and UK (Bristol, Portsmouth, Stevenage)]. MMS was formed in 1990 by Matra Espace of France (Lagadere) and Marconi Space Systems (GEC) of UK (since 1994). MMS employs 5,000 people, 2300 in France and 2700 in the UK. MMS covers science (SOHO, Giotto, Hipparcos), Earth observation (Spot series, ERS, Polar Platform for Envisat, Me top), communications (builder of the Eurostar and Leostar platforms) launch vehicles, military reconnaissance SIC (Helios ), etc. MMS is also an EO instrument builder (HRV on Spot series, ASAR, GOMOS, AASTR, SEVIRI, etc.)- As of 2000 MMS is called Astrium SAS in France and Astrium Ltd. in the UK (see Astrium)

MMW ......... Millimeter Wave (spectral range of 1mm to 10 mm) MOBILHY ..... Modelisation du Bilan Hydrique (HAPEX campaign) MOBLAS ...... Mobile Laser System (USA) MOCE ......... Marine Optical Characterization Experiment (campaign) MoD . . . . . . . . . . Ministry of Defence (London, UK) MODE ........ Middeck 0-Gravity Dynamics Experiment (Shuttle payload) MO Disk ....... Magneto-Optical Disk MODTRAN .... Moderate-resolution LOWTRAN (see glossary under LOWTRAN) MOEM ........ Micro Optoelectronic-Mechanical (device) MOMS ........ Modular Optoelectronic Multispectral Scanner (Shuttle payload of

1983 and 84), J.12 and J.13 MONEX ....... Monsoon Experiment (campaign)


MOP .......... Meteosat Operational Programme (European series of weather satellites from EUMETSAT)

MOS . . . . . . . . . . Marine Observation Satellite (NASDA Satellite, MOS-1 Launch: 1987, MOS-1b launch: Feb. 1989), D.23

MOS .......... Metal-Oxide Semiconductor (solid-state technology); CMOS= Complementary MOS

MOSFET ...... Field-Effect Transistor (FET) using MOS technology MOSES . . . . . . . . Molecules in Outer Space and Earth Stratosphere (Swedish Mission,

renamed ODIN), A.20 MOVPE . . . . . . . Metalorganic Vapor Phase Epitaxy (a growth technique) MOZAIC ...... Measurement of Ozone by Airbus In-Service Aircraft, P.40.1 M2P2 .......... Mini-Magnetospheric Plasma Propulsion (a new propulsion system/

technique, funded by NASA The technology creates an electromagnetic bubble around a S/C and lets the solar wind push the S/C) 2111J

MPAe .......... Max-Planck-Institut fiir Aeronomie (Katlenburg-Lindau, Germany) MPE ........... Max-Planck-Institut fiir Extraterrestrik (Garching, Germany) MPEG . . . . . . . . . Motion Pictures Experts Group [compression/decompression stan

dard for data, MPEG-1 is a video coding standard for small images on internet (since 1993), MPEG-2 is a standard for high-quality video images (since 1996)]

MPEI . . . . . . . . . . Moscow Power Engineering Institute, builder of EO instruments like radiometers [also known as SRB/MPEI (Special Research Bureau of MPEI)]

MPG .......... Max-Planck-Gesellschaft zur Forderung der Wissenschaften e.V. (Germany). MPG is the single largest government-funded research organization in Germany. MPG is the successor ofthe Kaiser-Wilhelm-Gesellschaft founded in 1911. MPG maintains 68 research centers (and extensions), referred to as MPis (Max Planck Institutes), throughout Germany. The organization employs about 11,000 people, including some 3000 scientists. In addition to its workforce MPG hosts a large number of (more than 5000 mostly on a yearly basis) research fellows, doctoral candidates, and guest scientists from other institutions. Basic research in the natural and human sciences is emphasized in all MPis. Major fields of research are: physics, chemistry, biology, physical chemistry, astronomy, mathematics, computer science, and medicine.

MPI ........... Max-Planck-Institut (generic) MPIA . . . . . . . . . . Max Planck Institut fur Astronomie (Heidelberg, Germany) MPICh ......... Max-Planck-Institut fur Chemie (Mainz, Germany) MPifM ......... Max-Planck-Institut fiir Meteorologie (Hamburg, Germany) MPIK .......... Max-Planck-Institut fiir Kernphysik (Heidelberg, Germany) MPNE . . . . . . . . . Microgravity Plant Nutrient Experiment (Shuttle payload) MPSE . . . . . . . . . Morelos Payload Specialist Experiments (Shuttle payload) MPT ........... Ministry of Posts and Telecommunication (Tokyo, Japan) MRF . . . . . . . . . . Meteorological Research Flight (UK) MRI . . . . . . . . . . . Magnetic Resonance Imaging MS . . . . . . . . . . . . Multispectral (data) MSAS ......... Multi-Transport Satellite Augmentation System (GNSS-1 element of

Japan) MSFC . . . . . . . . . Marshall Space Flight Center (Huntsville, AL, DAAC of NASA EOS

Program; Note: MSFC/DAAC closed as of March 31, 1997 due toreduced NASA budgets)

MSK . . . . . . . . . . . Minimum Shift Keying MSL . . . . . . . . . . . Material Science Laboratory (Shuttle payload) MSS . . . . . . . . . . . Mobile Servicing System [a robotics system consisting of the elements:

SSRMS (Space Station Remote Manipulator System), SPDM (Special Purpose Dextrous Manipulator), and MBS (Remote Mobile Server

2111) http://www.niac.usra.eduffopics/Summary _Pages/Robert_ Winglee.html


Base System), all systems are built by Canada, that will be used to assemble and maintain the ISS (International Space Station)]

MSSL .......... Mullard Space Science Laboratory (University College London, UK) MSTI . . . . . . . . . . Miniature Sensor Technology Integration (a Phillips Laboratory

technology demonstration program, Kirtland AFB, Albuquerque, NM)

MSU-E ........ Multispectral Scanner- Electronic Scanning MSU-K ........ Multispectral Scanner- Circular Scanning MSU-M ........ Multispectral Scanner- Low Resolution MSU-S ......... Multispectral Scanner-Moderate Resolution MSU-SK ....... Multispectral Scanner-Moderate Resolution, Conical Scanning MSW .......... Medium and Short Wave (spectrum) MSX . . . . . . . . . . Midcourse Space Experiment (DoD mission, M.14, Note: MSX experi

ments are also performed from several Shuttle missions in conjunction with the MSX spacecraft)

MTBF . . . . . . . . . Mean Time Between Failure MTF . . . . . . . . . . . Modulation Transfer Function MTI . . . . . . . . . . . Moving Target Indication MTPE ......... Mission To Planet Earth [US program, see D.12, Note: As of January

1998 MTPE was renamed by NASA to "Earth Science Enterprise" (ESE)]

MW ........... Microwave (spectral region with wavelengths from 1mm to 1m) MWIR ......... Mid-Wavelength Infrared (about 3-5 ~m) MWR . . . . . . . . . . Microwave Radiometer

N NzO ........... Nitrous oxide NzOs . . . . . . . . . . Nitrogen pentoxide N/A ........... Not Applicable (Not Available) NABE ......... North Atlantic Bloom Experiment (campaign within JGOFS) NAC ........... Narrow-Angle Camera NACA ......... National Advisory Committee on Aeronautics (USA, 1915-1958, pre

decessor organization of NASA) NADC ......... Naval Air Development Center (Warminster, PA, USA) NAE ........... National Aeronautical Establishment of NRC (National Research

Council, Canada) NAL ........... National Aerospace Laboratory, Japan NAPP .......... National Aerial Photography Program (of USGS). NAPP was initiated

in 1987 with the objective to acquire and archive aerial photography (using either color or black-and-white film) on a five-year cycle at a scale of 1:40,000. NAPP is a program jointly funded by federal agencies and states that choose to participate. Data are available through the EROS Data Center in Sioux Falls, SD, USA

NARE ......... North Atlantic Regional Experiment (campaign) NARSS ........ National Authority for Remote Sensing and Space Sciences, (Cairo,

Egypt) NAS ........... National Academy of Sciences (USA) NAS ........... National Airspace System (FAA, USA) NASA ......... National Aeronautics and Space Administration (USA, since 1958) NASNARC .... NASNAmes Research Center (Moffett Field, CA, since 1939) NASA!DFRC ... NASA/Dryden Flight Research Center (Edwards AFB, CA, since

1946) NASNGSFC ... NASNGoddard Space Flight Center (Greenbelt, MD, since 1959) NASNHQ . . . . . . NASNHeadquarters (Washington, DC) NASNJPL ..... NASNJet Propulsion Laboratory (Pasadena, CA, since Dec. 3, 1958) NASNJSC ..... NASNJohnson Space Center (Houston, TX, since 1961) NASNKSC ..... NASA/Kennedy Space Center (Cap Canaveral, FL, since 1967)


NASNLaRC .... NASNLangley Research Center (Hampton, VA, since 1917) NASNLeRC .... NASNLewis Research Center (Cleveland, OH, since 1941). Note:

LeRC was renamed to John H. Glenn Research Center (NASNGRC) on March 1. 1999

NASNGRC .... NASNJohn H. Glenn Research Center NASNMSFC . . . NASNMarshall Space Flight Center (Huntsville, AL, since 1960) NASNSSC ..... NASNStennis Space Center (Pearl River, MS). Testing of rockets and

engines (Shuttle); colocation of US Navy facilities, Naval Oceanographic Office, Naval Research Laboratory, National Data Buoy Center (NDBC, a NOANNWS facility), etc.

NASDA ........ National Space Development Agency (of Japan, since 1969) NASDNEOC ... NASDNEarth Observation Center (Tokyo, Japan, since 1978) NASDNEOPD . NASDNEarth Observation Planning Department NASDNEORC . NASDNEarth Observation Research Center (Tokyo) NASDNEOSD . . NASDNEarth Observation Satellite Department NATAC ........ North Atlantic Chemistry Experiment (campaign) NAVCEN . . . . . . Navigation Center (US Coast Guard, Alexandria, VA- NAVCEN is re

sponsible for gathering system status information on GPS, OOPS, Omega, and Loran-C)

NAVSOC ...... Naval Satellite Operations Center (US Navy, NAVSOC HQ is at Point Mugu, CA, since 1962. NAVSOC facilities strecht across the USA)

NAVSTAR-GPS . Navigation System with Time and Ranging- Global Positioning System (Precision real-time position determination system ofthe US Air Force, H.4)

NAWC ......... Navy Air Warfare Center (Point Mugu, CA) NaSBE ......... Sodium Sulfur Battery Experiment (Shuttle payload) NBIOME ...... Northern Biosphere Observation and Modelling Experiment (cam-

paign) NBS . . . . . . . . . . . National Bureau of Standards (USA, since 1901, predecessor of NIST) Nb:AlOx:Nb .... Niobium:Aluminum Oxyde:Niobium (tunnel junction material) Nd: YAG ....... A neodymium-doped yttrium aluminum garnet crystal (solid-state) la

ser NCAR ......... National Center for Atmospheric Research (Boulder CO, NCAR is

managed and operated by the University Corporation for Atmospheric Research (UCAR) under the sponsorship of the National Science Foundation (NSF), NCAR has two laboratory sites in Boulder: Mesa Laboratory smce 1966, Foothills Laboratory since 1992)

NCAR/A TO .... NCAR I Atmospheric Technology Division NCAR/ACD .... NCAR I Atmospheric Chemistry Division NCAR/RAF .... NCAR I Research Aviation Facility NCAR/MMM . . . NCAR I Mesoscale & Microscale Meteorology Division NCAR/COD .... NCAR I Climate and Global Dynamics Division NCAR/HAO .... NCAR I High Altitude Observatory NCC ........... National Climatic Center (USA) NCDC . . . . . . . . . National Climatic Data Center (of NOANNESDIS, Asheville, NC) NCDS ......... NASA Climate Data Center (at GSFC, Science data archive for atmo

spheric chemistry and climate (ERBE, etc.) NDBC ......... National Data Buoy Center [a NOANNWS facility at Stennis Space

Center (SSC), MS, since 1982; between 1970-1982 NDBO (NOAA Data Buoy Center) was the predecessor of NDBC at SSC]

NDIR .......... Non-Dispersive Infrared (Spectrometer) NDOC ......... National Oceanographic Data Center (USA) NDSC ......... Network for the Detection of Stratospheric Change NDTP ......... North Dakota Thunderstorm Project (campaign) NDVI . . . . . . . . . . Normalized Difference Vegetation Index NEAT . . . . . . . . . Near Earth Asteriod Tracking (NASNJPL ground-based program to

track NEO asteroids)


NEC ........... Nippon Electric Company, Tokyo, Japan NEDRES ...... National Environmental Data Referential Service (NOAA service) NElS .......... National Earthquake Information Service (USGS, Denver, CO) NEAR ......... Near Earth Asteroid Rendezvous SIC (of NASA with a launch Feb. 17,

1996, the mission is managed and operated by JHU/ APL ). As of March 2000, NASA renamed the satellite to "NEAR Shoemaker" in honor of Eugene M. Shoemaker, a geologist.

NE~R ......... Noise Equivalent Delta (or Differential) Radiance (system sensitivity) NE~ T . . . . . . . . . Noise Equivalent Delta (or Differential) Temperature (system sensitiv-

ity), also referred to as NEDT NEFD ......... Noise-Equivalent Flux Density (see Glossary) NEMO ......... Navy EarthMap Observer (D.25) NEMS ......... Nano-Electromechanical System (sensor technology) NEO . . . . . . . . . . Near Earth Object NEP ........... Noise-Equivalent Power NER ........... Noise Equivalent Radiance NERC ......... Natural Environment Research Council (Swindon, UK) NERSC ........ Nansen Environmental and Remote Sensing Centre (Bergen, Nor

way), formerly known as NRSC, a non-profit research institute affiliated with the University of Bergen.

NESR ......... Noise-Equivalent Spectral Radiance (see Glossary) NESDIS ....... National Environmental Satellite Data and Information Service

(NOAA centers at Suitland, MD, and Boulder, CO) NEWS ......... NOAA Earth Watch Service (information system) NEXRAD ...... Next-Generation Weather Radar (a US ground-based system with the

name of WSR-88D (Weather Surveillance Radar-1988 Doppler) NFOW ......... Narrow Field of View (sensor) NGDC ......... National Geophysical Data Center (NOAA facility at Boulder, CO,

since 1965) NGST ......... Next Generation Space Telescope [NASA satellite (an infrared obser

vatory positioned at L2) with a planned launch in 2009 to replace HST (Hubble Space Telescope)]

NH3 . . . . . . . . . . . Ammonia NH4 . . . . . . . . . . . Ammonium (ammonia radical) NiCd .......... Nickel Cadmium (battery) NiHz .......... Nickel Hydrogen (battery) NiMH ......... Nickel Metal Hydride (battery) NNMRS ....... National Natural Resources Management System [an agency of DOS

(Department of Space), India] NO ............ Nitric oxide NOz ........... Nitrogen dioxide N03 . . . . . . . . . . . Nitrate radical NOx (NOx) ..... Nitrogen oxides (NO, NOz, N03) NO (NOy) ..... Total active nitrogen NOBRSC ...... National Operational Hydrologic Remote Sensing Center (of NOAA/

NWS at Chanhassen, MN, USA) NIAC . . . . . . . . . . NASA Institute for Advanced Concepts NICMOS ....... Near-Infrared Camera and Multi-Object Spectrometer (Hubble sen-

. sor, built by Ball Aerospace) NIES .......... National Institute of Environmental Studies, Tsukuba, Japan NIH-R ......... National Institute of Health (Shuttle experiment) NIIEM ......... Scientific and Research Institute of Electromechanics, Istra (Moscow

Region), Russia; NIIEM was founded in 1960 by VNIIEM. In 1992 the institute NIIEM became an independent entity. Development of LEO meteorological satellites.

NIIR . . . . . . . . . . State Radio Scientific Research Institute, Moscow; developer/builder of communication equipment in the widest sense, participation in pro-


grams: Orbita, Ekran, Ekran-M, Moskva, Gorizont, Gals, Express, Interkosmos, Intersputnik, Apollo-Soyuz, Vega, Phobos, etc.

NILU .......... Norwegian Institute for Air Research (Lillestrom, Norway) NIMA ......... National Imagery and Mapping Agency (Arlington, VA, a US govern

ment agency established in Oct. 1996). NIMA incorporates the Defence Mapping Agency (DMA), the Central Imagery Office, and the Defense Dissemination Office as well as CIA:s Photographic Interpretation Center. NIMA is also the principal buyer of commercial imagery for all DoD organizations.

NIMBUS . . . . . . . NASA EO missions series, M.17 NIMS .......... Navy Ionospheric Monitoring System (H.6) NIPR .......... Nippon Institute for Polar Research, Japan NIR ........... Near Infrared (spectrum, from 0.75 to about 1.3 ~m) NIST .......... National Institute of Standards and Technology (USA, an agency of

DOC, formerly National Bureau of Standards, since 1901) NIVR .......... Nederlands Instituut voor Vliegtuigontwikkeling en Ruimtevaart

(Netherlands Institute for Air and Space Development, Delft, The Netherlands, since 1946)

NKAU ......... National Space Agency of Ukraine (since 1992), also referred to as NSAU

NLO ........... Nonlinear Optics (NLO is widely used in solid-state laser technology) NLR ........... Nationaal Lucht- en Ruimtevaartlaboratorium (National Aerospace

Laboratory, Amsterdam and Noordoostpolder, Netherlands) since 1961. NLR is of NLL (Nationaal Luchtvaart Laboratorium) heritage which was founded in 1937.

NMC .......... National Meteoroligical Center (USA) NMHC ......... Non-methane hydrocarbons NMOS ......... N-channel MOS (Metal-Oxide Semiconductor) NMP .......... New Millennium Program (NASNJPL) NNSS .......... Navy Naviation Satellite System (USA, also known as the 'Transit' sys

tem, was the world's first satellite navigation system, H.6) NOAA ......... National Oceanic and Atmospheric Administration (NOAA is an

agency of the US Department of Commerce, established in 1970 (predecessor ESSA), it has the following major divisions: NOS (National Ocean Service), NWS (National Weather Service), NMFS (National Marine Fishenes Service), NESDIS (National Environmental Satellite, Data and Information Service), OOAR (Office of Oceanic and Atmospheric Research), and ONCO (Office of NOAA Corps Operations).

NOANAL ...... NOANAeronomy Laboratory (Boulder CO) NOANAOML .. NOANAtlantic Oceanographic and Meteorological Laboratory, Mi

ami, FL. The HRD (Hurricane Research Division) is part of AOML. NOANARL .... NOANAir Resources Laboratory, Silver Spring, MD. Note: ARLcon

sists of the HQ-Division in Silver Spring, MD, the ATTD in Oak Ridge TN, the ASMD (Atmospheric Sciences Modeling Division) in Research Triangle Park, NC, the FRD (Field Research Division) in Idaho Falls, ID, and the SRRB (Solar Radiation Research Branch) in Boulder, CO.

NOANAOC .... NOANAircraft Operations Center, MacDill AFB, Tampa, FL. Note: AOC was created in 1983 [initially known as OAO (Office of Aircraft Operations)] to manage NOAA aircraft, personnel, budget and facilities in support of NOAA aircraft programs. AOC is under ONCO.

NOANATDD .. NOANAtmospheric Turbulence and Diffusion Division, Oak Ridge, TN

NOANCDC .... NOANC!imate Diagnostics Center (Boulder, CO) NOANCMDL .. NOAN Climate Monitoring and Diagnostics Laboratory, Boulder CO.


NOAA/ERL .... NOAA/Environmental Research Laboratories, headquartered in Silver Spring, MD. (under OOAR). All NOAA laboratories are run through OOAR/ERL, these are: AL, AOML, ARL, CDML, ETL, FSL, GFDL, GLERL, NSSL, PMEL, SEL, CDC, and the Joint Institutes.

NOAAJETL .... NOAA/ Environmental Technology Laboratory, Boulder, CO, (for-merly WPL = Wave Propagation Laboratory)

NOANFSL ..... NOANForecast Systems Laboratory (Boulder, CO) NOAA/GFDL ... NOAA/Geophysical Fluid Dynamics Laboratory, Princeton, NJ. NOANGLERL . NOAA/Great Lakes Environmental Research Laboratory, Ann Arbor,

MI. NOANNSSL ... NOANNational Severe Storms Laboratory, Norman, OK. NOAA-NESDIS . NOANNational Environmental Satellite Data and Information Ser

vice, Suitland, MD.- NESDIS functions are: Satellite Operations, Satellite Data Processing and Distribution, Research and Applications, Systems Development, National Climatic Data Center (NCDC), National Oceanic Data Center (NO DC), National Geophysical Data Center (NGDC).

NOANNCDC .. NOAA-NESDIS/National Climatic Data Center, Asheville, NC. NOANNDBC .. NOAA-National Data Buoy Center (a NOANNWS facility at Stennis

Space Center, MS) NOANNGDC .. NOAA-NESDIS/National Geophysical Data Center, Boulder, CO NOANNODC .. NOAA-NESDIS/National Oceanographic Data Center (Silver Spring

MD) NO ANN OS .... NOANNational Ocean Service- NOS functions are: coast and geodet

ic survey, ocean resources conservation and assessment, ocean and coastal resources management, ocean and earth sciences.

NOANNSIDC .. NOANNational Snow and Ice Data Center, Boulder, CO (NSIDC is located at the University of Colorado at Boulder)

NOANNWS .... NOANNational Weather Service- NWS functions are: meteorology, hydrology, systems operations, systems development, national meteorological center, national data buoy center

NOANOAO .... NOAA/Office of Aircraft Operations, Miami, FL (old designation) NOANOOAR . . NOAA/Office of Oceanic and Atmospheric Research - OOAR func

tions: oceanic research program, environmental research laboratories. NOANPMEL ... NOANPacific Marine Environmental Laboratory (Seattle, WA, since

1973) NOAA/SEC .... NOAA/Space Environment Center (Boulder, CO) NOANSEL ..... NOAA/Space Environment Laboratory (Boulder, CO), Note: NOAA/

SEL changed its name to NOAA/SEC in 1997 NODS ......... NASA Ocean Data System (located at JPL; Measurements in the ar

chive are related to altimetry, scatterometry, and microwave radiometry. NODS archives and distributes data products for TOPEX/Poseidon)

NOPEX ........ Northern-Hemisphere Climate £rocesses Land-surface Experiment (campaign)

NOPP ......... National Oceanographic Partnership Program (USA, since 1997, NOPP has a mandate from Congress). The objective is to foster cooperation and partnerships among federal agencies, academia, industry and other members of the oceanographic scientific community.

NORCSEX ..... Norwegian Continental Shelf Experiment (campaign) NORDA ....... Northern Oceans Research and Development Activities (Canada) NORSEX ...... Norwegian Remote Sensing Experiment (campaign) NOSC ......... Naval Ocean Systems Center (San Diego, CA) NOSL ......... Night/Day Optical Survey of Lightning (Shuttle experiment) NOSS .......... Naval Ocean Surveillance Satellite, also referred to as "Whitecloud,"

"White Cloud" or "Classic Wizzard" (a US Navy S/C series, sponsored


by NRO, and launched from V AFB, CA on Atlas vehicles). 2112) NOSS is a wide area ocean surveillance system used to determine the location of radio and radar transmissions, using triangulation. - Each NOSS launch placed a cluster of one primary satellite and three smaller subsatellites (that trail along at distances of several hundred m apart in a triangle formation) into low polar orbit. This satellite array can determine the location of radio and radars transmitters, using triangulation, and the identity of naval units, by analysis of the operating frequencies and transmission patterns. NOSS used the ELINT technique called TDOA (time difference of arrival), rather than true interferometry. NOSS-1launch April30, 1976 (1100 km altitude, inclination= 63.5°), NOSS-2launch Dec. 8, 1977, NOSS-3launch March 3, 1980, NOSS-4 launch Feb .9, 1983, NOSS-8launch May 15, 1987 (also referred to as USA-22), NOSS-9launch Sept. 5, 1988 ( amo known as USA-32). -Second generation NOSS satellites were launched starting in 1990. There are three groups of the 2nd generation NOSS satellites each having three satellites in close proximity to one an0ther. The first NOSS-2-1 triplet was launched on June 8, 1990 on a Titan-IV vehicle from Cape Canaveral; the second NOSS-2-2 triplet was launched on Nov. 8, 1991; and the third triplet of NOSS-2-3 was launched May 12, 1996 from VAFB.

NOWES ....... Northern Wetlands Study (campaign) NOx . . . . . . . . . . . Nitrogen oxides NOy . . . . . . . . . . . Total reactive nitrogen NPL ........... National Physical Laboratory (Teddington, Middlesex, UK; NPL is an

agency of the Department of Trade and Industry) NPO ........... Naulshno Proizwodstwennoje Objedijenie (Scientific/Research Pro

duction Association, Russia) NPO AP . . . . . . . NPO for Automation and Instrument Engineering, Moscow; sinc.e

1947; participation in the following programs: Venera, Mars, Luna, Soyuz, Proton, Zenit, Energia-Buran; builder of 0n-board guidalille and navigation systems

NPO Geofizika .. Moscow; since 1908, a major enterprise for the development oLautomatic and visual opto-electronic instruments; participatiw in natiomil programs: Vostok, Salyut, Soyuz, MIR, Energia-Buran,letc.

NPO Machinostroyenia Russian company, Reutov, Moscow Region, ibriilfuniiintegra-tor of SIC (ALMAZ series), participation in programs: Kosmos, :Proton, Polyot, Salyut, etc.

NPO Plan eta .... Scientific and Research Center on Space Hydrometeorology (Moscow, since 1974), operators of satellites (Meteor, Okean, Resurs, GOMS series) along with corresponding ground segments, providers of se!Vices to the user community in the areas of meteorology/climate, oceanography, Earth resources, and ecological monitoring. From an organizational point of view, NPO Planeta is an agency positioned underROSHYDROMET, the 'Committee for Hydrometeorology and Environmental Monitoring'

NPO PM Research and Production Association of Applied Mechanics (Prikladnoi Mekaniki), Krasnoyarsk (a closed city until1991) Siberia. NPO PM was founded m 1959, since 1977 it is builder/integrator of communication satellites (Gorizont, Express, Molniya-1, -2, -3, Raduga-1, Ekran, Ekran-M, Luch, Radio, etc.), navigation satellites (GLONASS, Tsikada), and geodetic satellites (GEO-IK, Etalon); advanced programs (Express-M, Go nets, Arkos, Mayak, Gals)

NPO Vega . . . . . . Russian space/defense industry consortium, Moscow, designers and builders of SAR instruments, etc., operators of airborne instruments

2112)A. Andronov, "The US Navy's "White Cloud" Spaceborne ELINT System," in Zarubezhnoye Voyennoye Obrozreniye (Foreign Military Review), ISSN 0134-921X, No.7, 1993, pp. 57-60, translated by Allen Thomson


NPO Yuzhnoye . . Design Office Yuzhnoye, in Dnepropetrovsk, Ukraine (builder of OKEAN SIC series)

NPOESS ....... National Polar-orbiting Operational Environmental Satellite System (merged POES and DMSP series, with launches projected for 2008 and beyond)

NPOP ......... NASA Polar Platform NPP ........... NPOESS Preparotary Project NPS ........... Naval Postgraduate School (Monterey, CA) NRC ........... National Research Council (Washington, DC, USA) NRC (NRCAN) . Natural Resources Canada (Ottawa, Canada) NRCS . . . . . . . . . . Normalized Radar Cross-Section (an aspect of ocean surface reflectiv

ity, also referred to as 0°) NRCT ......... National Research Council of Thailand NRL ........... Naval Research Laboratory (Washington, DC). NRL is the US Navy's

corporate research and development laboratory, created in 1923 with over 4000 personnel (among them 1500 scientists) in the 1990s. NRL maintains 15 research sites throughout the US. The three main NRL sites are at: Washington DC, NRL!SSC (Stennis Space Center in Bay St. Louis, MS), and NRL!MRY (Monterey, CA).

NRL/NCST ..... NRL/Naval Center for Space Technology NRL!RSD . . . . . . NRL!Remote Sensing Division NRLM ......... National Research Laboratory of Meteorology (Japan) NRO .......... National Reconnaissance Office (agency of DoD, Chantilly, VA,

USA). NRO sponsors and operates US reconnaissance SIC (Corona series, etc.). The primary user of the imagery is NIMA.

NROSS ........ Navy Remote Ocean Sensing System (satellite) NRSA ......... National Remote Sensing Agency (since 1975, Balanagar, Hyderabad,

India) NRSC ......... National Remote Sensing Centre (UK, this agency was privatized in

1989, commercial sale of remote sensing data, operator of UK-PAF for ESA)

NRSCC ........ National Remote Sensing Center of China (Beijing) NRZ ........... Non-Return to Zero (communication signal parameter) NSBF .......... National Scientific Balloon Facility (NASA-owned facility in Fort

Sumner, NM) NSC ........... Norwegian Space Centre (Oslo, Norway) NSERC ........ Natural Sciences and Engineering Research Council (Canada) NSF ........... National Science Foundation (Arlington, VA, USA; since 1950; NSF is

an independent govenment agency responsible for promoting science and engineering). About 20,000 programs per year are supported by NSF.

NSI ............ NASA Science Internet - an international dual protocol (TCP/IP and DECnet) network (successor to SPAN)

NSIDC ......... National Snow and Ice Data Center (Boulder, CO, NOAA facility at University of Colorado, established in 1982). NSIDC is co-located with WDC-A (World Data Center A for Glaciology). NSIDC is also a DAAC site of the EOS Program. NSIDC has extensive holdings of cryospheric and polar ocean surface-flux data and routinely produces sea ice maps from SSM/I sensor.

NSMC ......... National Satellite Meteorological Center [since 1971, NSMC is theresearch and operational facility of CMA (China Meteorological Administration)]. NSMC has ground stations in Beijing, Guangzhou, and Urumqi.

NSPO .......... National Space Program Office (Hsin-Chu City, Taiwan) NSSDC ........ National Space Science Data Center(at NASA/GSFC) NSSL .......... National Severe Storms Laboratory (Norman, OK) NSTAR . . . . . . . . NASA Solar Electric Power (SEP) Technology Application Readiness


NSW .......... New South Wales (Australia) NTIS .......... National Technical Information Service (USA) NTS ........... Navigation Technology Satellite (DoD/NRL program ofthe 1970s also

referred to as Timation which predated the GPS program) NTSC .......... National Television Standards Committee (US TV display standard

which is also adopted by a number of other countries. This is a 525-line video signal with a 3.58 MHz chroma subcarrier at 60Hz)

NTT ........... Nippon Telegraph and Telephone Corporation (Japan) NWP . . . . . . . . . . Numerical Weather Prediction NWS .......... National Weather Service (USA)

0 Oz . . . . . . . . . . . . . Molecular oxygen 03 ............. Ozone Ox (Ox) ........ Odd oxygen (0+03) OACT . . . . . . . . . Office of Advanced Concepts and Technology (NASA, formerly

OAST) OAI ........... Ohio Aerospace Institute, Cleveland, OH [consortium of nine Ohio

universities, NASNGRC (Lewis Field in Cleveland), AFRL (Dayton), and private industry]

OARE . . . . . . . . . Orbital Acceleration Research Experiment (Shuttle payload) OACES ........ Ocean-Atmosphere Carbon Exchange Study (campaign) OASIS-1 . . . . . . . Orbiter Autonomous Supporting Instrumentation System (Shuttle

payload) OASIS ......... On-Line Data Access and Service Information System (Catalog system

at NOAA-NCDC) OAST . . . . . . . . . . Office of Application and Space Technology (NASA, Shuttle payloads

are also designated by this name- OAST-1, OAST-2, etc.) OBC ........... On-Board Computer OBS ........... Observatoire Paris-Mendon (France) OCE . . . . . . . . . . . Ocean Color Experiment (Shuttle payload) OCEAN ....... Ocean Color Environment Archive Network (ESA Program) OClO .......... (Cl02) Chlorine dioxide OCOS ......... Ocean Climate Observing Study (campaign) OCTW ......... Optical Communications Through Windows (Shuttle experiment) ODERACS ..... Orbital Debris Radar Calibration System (Shuttle payload) ODIN ......... Proposed Swedish astronomy and aeronomy mission (A.20, in Norse

mythology Odin (also called Woden or Wotan) is one of the principal gods)

OECD ......... Organization for Economic Cooperation and Development OEDIPUS ...... Observations of Electric-field Distributions in the Ionosphere Plasma

a Unique Strategy (Canadian sounding rocket missions from Andoya, Norway and Poker Flats, Alaska)

OES ........... Office of Earth Science (NASNHQ, since 1998, formerly Office of Mission to Planet Earth (OMTPE))

OEX . . . . . . . . . . Orbiter Experiments (Shuttle) OGLOW ....... Sun Orbiter Glow (Shuttle experiment) OH . . . . . . . . . . . . Hydroxyl radical OHB-System .... Orbital- und Hydrotechnologie Bremen System GmbH (since 1958,

originally known as: Otto Hydraulik Bremen). A mid-sized aerospace and telecommunication company, located in Bremen, Germany- with a number of company participants and subsidiaries in Germany and Italy. OHB-System is part of the Fuchs Gruppe (since 1981 ). Satellites built by the Fuchs Gruppe are: BremSat, SAFIR-1, -2, ABRIXAS, DIAMANT, MITA. Note: The company CARLO GAVAZZI SPACE S.p.A, Milan, Italy was taken over by the Fuchs Gruppe in 1996; OHBTeledata was founded in 1996.


OICETS ....... Optical Interorbit Communications and Engineering Test Satellite (of NASDA, Japan)

OIP ........... Optroniclnstruments & Products [OIP is trading under the trade name 'Delft Sensor Systems' (DSS)], located in Oudenaarde, Belgium

OKEAN ....... Ukrainian/Russian satellite series, D.26 OMNI ......... Operating Missions as Nodes on the Internet. OMNI is the first end-to

end demonstration of operating NASA missions as nodes on IP. ONERA ....... Office National d'Etudes et de Recherches Aerospatiales- The French

Aeronautics and Space Research Center (Chatillon, Meudon, Palaiseau, Avrieux, Mauzac, Toulouse, Lille, France) ONERA reports to the French Ministry of Defense. CERT (Centre d'Etudes et de Recherches de Toulouse) is a center of ONERA.It carries out research for and with the aeronautics, space and defense industries.

ONR .......... Office of Naval Research (HQ in Arlington, VA). ONR coordinates the science and technology programs of the US Navy and Marine Corps. NRL is a technical department of ONR.

OPO ........... Optical Parametric Oscillator (laser type) 0-QPN ........ Offset Quadriphase Pseudo-Noise ORFEUS ...... Orbiting Retrievable Far and Extreme Ultraviolet Spectrograph (Ger

man/US Shuttle payload) OREGIN ....... Organization of European GNSS Equipment and Services Industry (an

industry association to support development of Galileo equipment and services)

ORI ........... Ocean Research Institute (University of Tokyo, Japan) ORNL ......... ORNL (Oak Ridge National Laboratory), Oak Ridge, TN (of DOE) 0rsted . . . . . . . . . Danish research satellite, E.18 ORSTOM ...... Office de Ia Recherche Scientifique et Technique Outre-Mer (Paris,

Montpellier, Orleans, etc., France) also: Unstitut francais de recherche scientifique pour le developpement en cooperation (French scientific research institute for development in cooperation). In 1998 OSTROM was renamed to IRD (lnstitut de Recherche pour le Developpement)

OSA . . . . . . . . . . . Optical Society of America OSDPD ........ Office of Satellite Data Processing and Distribution (of NOAA) OSC . . . . . . . . . . . Orbital Sciences Corporation (Dulles, VA, USA, since 1982, builder of

small satellites and instruments, owner/operator of commercial launch services for small payloads, Pegasus vehicle, etc.). ORBCOMM, ORBIMAGE and Magellan (GPS receivers) are affiliates of OSC, so are CTA Space Systems (McLean, VA) and MacDonald Dettwiler Associates Ltd (MDA, Vancouver, BC).

OSI ............ Open System Interconnect (a standard for open communication) OSKAR ........ Orbiting Satellite Carrying Amateur Radio (initially a satellite series of

a USA-based group of amateur radio enthusiasts; OSKAR-1 was launched Dec. 12. 1961; in 1969 AMSATwas founded to give amateur radio satellites an international base)

OSS ........... NASA's Office of Space Science (Shuttle payloads, etc.) OSSS .......... One Stop Satellite Solutions (Ogden, UT, since 1996, a spin-off com

mercial company of CAST at Weber State University). OSSS built MPA (Multi-Payload Adapter) for JAWSAT. OSSS is also the US contact/ partner for the Dnepr launch vehicle of ISC Kosmotras of Moscow.

OSTC . . . . . . . . . . Federal Office for Scientific, Technical, and Cultural Affairs of Belgium [also referred to as SSTC (Services Federaux des Affaires Scientifiques, Techniques et Culturelles, Belgium)]

OSTA . . . . . . . . . . Office of Space and Terrestrial Applications, NASA (a designation that was also given to the early Shuttle payloads)

OSVS . . . . . . . . . . Orbiter Space Vision System (Shuttle payload) OTTER ........ Oregon Transect Ecosystem Research (campaign)

1454 Appendix B: Acronyms and Abbreviations ----------------

OWWS ........ Operational Windshear Warning System (NCAR)

p

PACSAT . . . . . . . A Protocol suite first developed by SSTL. PACSAT uses packet radio techniques in the microsatellite system to transmit its data over the satellite RF link. Several layers of protocol are implemented in the PACSAT suite, at the lower level HDLC (High-Level Data Link Control) and X.25 provide the functions of packet multiplexing, error detection and ARQ (Automatic-Repeat Request) error correction. PACSAT is a point-to-multipoint protocol (broadcast); small ground terminals in the satellite footprint receive/send the data. The PACSAT protocol suite is also supporting data communications within the radio amateur community.

PAF . . . . . . . . . . . Processing and Archiving Facility (ESA facilities for the ERS-1 mission in Europe: D-PAF at DLR/DFD, Oberpfaffenhofen, Germany; F-PAF at CERSAT, Brest, France; I-PAF at ASI Matera, Italy; UK-PAF at RAE, Farnborough, UK)

PAGES ........ Past Global Changes (IGBP core program) PAL ........... Phase Alternation Line (German TV display standard). PAL has 625

scan lines per frame at 50 Hz. PALACE ....... Profiling ALACE (Autonomous Lagrangian Circulation Explorer) of

NOAA/ AOML. PALACE is a later version of ALACE, first deployed in 1997. PALACE buoys have the added capability of data storage. They cary a sensor package providing measurements of various parameters such as conductivity and temperature. In the late 1990s, hundreds of PALACE floats in the Atlantic Ocean are reporting to data collection satellites on subsurface currents as well as profiles of salinity and temperature.

PALE .......... Paleoclimates for Arctic Lakes and Estuaries (campaign) PAM ........... Portable Automated Mesonet (weather stations of NCAR) PAMS .......... Passive Aerodynamically-Stabilized Magnetically-Damped Satellite

(Shuttle payload) PAN ........... Panchromatic (data) PAN . . . . . . . . . . . Peroxyacetylnitrate PANASH ....... Paleoclimates of the Northern and Southern Hemispheres (IGBP/

PAGES program under focus 1) PANSAT ....... Petite Amateur Naval Satellite (S/C of Naval Postgraduate School,

Monterey, CA, ejected from Shuttle) PARE . . . . . . . . . . Physiological and Anatomical Rodent Experiment (Shuttle experi

ment) PARLIQ ....... Phase Partitioning in Liquids (Shuttle experiment) PAS ........... PanAmSat <Omporation of Greenwich, CT (a daughter of Hughes Elec

tronics Corporation of Los Angeles, CA. PanAmSat is the world leader of commercial satellite-based communications services, launch of first satellite {Oalaxy-1) in 1983, launch of PAS-1 in 1988)

PASC .......... Polar Atmospheric and Snow Chemistry (IGBP/IGAC project) PASDE ........ Photogramrnetric Appendage Structural Dynamics Experiment

(Shuttle) PBL . . . . . . . . . . . Planetary Boundary Layer PbS . . . . . . . . . . . . Lead Sulfide (detector material) PbSi ........... Lead Silicon: (detector material) PC ............ Photoconductive (detector) PCG ........... Protein Crystal Growth (Shuttle experiment) PCG/STES ..... Protein Crystal Growth I Single-Locker Thermal Enclosure System

(Shuttle experiment) PCM . . . . . . . . . . Pulse Code Modulation PD ............ Photodiode (detector)


PDA . . . . . . . . . . . Photodiode Array (detector) PDP ........... Plasma Diagnostics Package (Spacelab·2 sensor, studies ofthe interac

tion between the Earth's magnetic field and charged particles in the ionosphere)

PE&RS ........ Photogrammetric Engineering & Remote Sensing (ASPRS journal) PEACAMPOT . . Perturbation by East Asia Continental Air Mass to Pacific Oceanic Tro-

posphere (campaign) PEM-West ...... Pacific Exploratory Mission- West (campaign) PEP ........... Pole-Equator-Pole (transect of PANASH campaign) PGIM .......... Plant Growth Investigations in Microgravity (Shuttle experiment) PHCF .......... Pituitary-Growth Hormone Cell Function (Shuttle experiment) PHOTON . . . . . . Russian solar-terrestrial mission (K.8.1) PL . . . . . . . . . . . . . Phillips Laboratory of USAF (PL is headquartered at Kirtland Air

Force Base, Albuquerque, NM, and has locations at Hanscom AFB, Bedford, MA, and Edwards AFB, CA)

PI . . . . . . . . . . . . . Principal Investigator PID ........... Prototype International Directory (CEOS-defined Directory Inter

change Format (DIF) ); CEOS members operating an archive with PID capability are: CCRS, DLRJDFD, ESNESRIN, NASA, NASDA, NOAA, RAE, etc .. Hence, standardized archival access is possible (see: IDN).

PIDC . . . . . . . . . . Precision Instrument Development Center (of the National Science Council, Taiwan), Hsinchu, Taiwan ROC

PIK . . . . . . . . . . . . Potsdam Institut fiir Klimaforschung (Potsdam Institute for Climate Impaxct Research, Potsdam, Germany)

PILOT ......... Portable Inflight Landing Operations Trainer (Shuttle experiment) PILPS . . . . . . . . . Project for lntercomparison of Landsurface Parameterization

Schemes (WCRP/GEWEX project) PIN . . . . . . . . . . . . Positive Insulator Negative (diode) PIPOR . . . . . . . . . Program for International Polar Ocean Research PIXEL . . . . . . . . . Picture Element PLB ........... Personal Locator Beacon (COSPAS and S&RSAT) PLL . . . . . . . . . . . Phase Locked Loop (communication technique to enable integration

of voice and data) PLO . . . . . . . . . . . Phase Locked Oscillator PM ............ Phase Modulation (modulation technique of the main carrier) PM ............ Polymer Morphology (Shuttle experiment) PM ............ Post Meridiem (refers to the afternoon time designations in the US; a

time of 5 PM is equivalent of 17:00 hours in international notation) PMA . . . . . . . . . . Pressurized Mating Adapter (Shuttle) PMAP ......... Paleoenvironment Multiproxy Analysis and Mapping Project (see

PANASH campaign) PMG . . . . . . . . . . Plasma Motor Generator (Q.36.5) PMOD/WRC ... Physikalisch-Meteorologisches Observatorium Davos, World Radi-

ation Center (Switzerland) PMS . . . . . . . . . . . Particle Measuring Systems Inc. (of Boulder CO) PMT ........... Photomultiplier Tube (detector) PMV &D . . . . . . . (Plume Model Validation and Development (campaign) PN ............ Pseudo Noise (code) PNEDC ........ Programme National d'Etude de la Dynamique du Climat (France) PNL . . . . . . . . . . . Pacific Northwest Laboratory (Richland, WA, USA) of DOE, operated

by Batelle Memorial Institute PNR ........... Pseudo Noise Number (a GPS series designation) PNRA ......... Italian National Programme for Antarctic Research PRN ........... Pseudo Random Noise POCC . . . . . . . . . Payload Operations and Control Center POEM-1 ....... Polar-Orbit Earth-Observation Mission (planned ESA Series) D.9


POES .......... Polar-orbiting Operational Environmental Satellites (NOAA series of operational polar orbiting satellites), G.13

POGO . . . . . . . . . Polar-Orbiting Geophysical Observatory POL ........... Prowdman Oceanographic Laboratories (UK) POLAR ........ NASNGSFC Solar-Terrestrial Mission (K.19) POLARIS . . . . . . Photochemistry of Ozone Loss in the Arctic Region in Summer (cam

paign) POLIN AT . . . . . . Pollution from Aircraft Emissions in the North Atlantic Flight Corridor

(campaign) PoSAT ......... Portuguese Satellite (D.40.9) PPARC . . . . . . . . Particle Physics and Astronomy Research Council, UK PPE . . . . . . . . . . . Phase Positioning Experiments (Shuttle payload) PPF ........... Polar Platform (ESA Columbus program, PPF is utilized for POEM

payloads) PPS ............ Precise Positioning Service (GPS) PRARE ........ Precision Rate and Range-Rate Equipment, H.7.2 PRF . . . . . . . . . . . Pulse Repetition Frequency PRIMA . . . . . . . . Piattaforma Riconfigurabile Italiana Multi-Applicativa (Reconfigur

able Italian Platform for Multiple Applications), ASI platform for a total SIC mass of 300-1000 kg

PRIRODA ..... Research module of the Space Station MIR (D.28) PRN ........... Pseudo Random Noise PROBE ........ Prototype Radiation Observation Experiment (campaign) ProSEDS ....... Propulsive Small Expandable Deployer System (tether experiment) PROTEUS . . . . . Platforme Reconfigurable pour !'Observation, les Telecommunica-

tions et les Usages Scientifiques (French minisatellite bus for a S/C mass less than 500 kg)

PROTEUS ..... Profile Telemetry of Upper Ocean Currents [a NOANPMEL mooring system, a taut-wire surface mooring with a toroidal float similar to ATLAS]

PSI . . . . . . . . . . . . Paul Scherrer Institute, Villigen, Switzerland (database of space envi-ronmental data)

PSC . . . . . . . . . . . Polar Stratospheric Clouds PSE . . . . . . . . . . . Physiological Systems Experiment (Shuttle) PSE ........... Polar Sunrise Experiment (campaign) PSK ........... Phase Shift Keying (a modulation technique) PSLR . . . . . . . . . . Peak Side Lobe Ratio PSLV .......... Polar Satellite Launch Vehicle (ISRO launch vehicle) PSN ........... Piano Spaziale Nationale (previous name of Italy's Space agency, now

ASI) PSRC .......... Polish Space Research Center, Warsaw, Poland PtSi ............ Platinum-silicide (detector material) PTT ........... Platform Transmitter Terminal (data collection platform for ARGOS

system) PTT ........... Public (Postal) Telephone and Telegraph (utility company). Refers to

operating agencies directly or indirectly controlled by governments in charge of telecommunication services in most countries of the world.

PTTI . . . . . . . . . . Precise Time and Time Interval PV ............ Photovoltaic (detector) PVTOS ........ Physical Vapor Transport of Organic Solids (Shuttle experiment) PWV . . . . . . . . . . Precipitable Water Vapor (atmosphere) PYREX ........ Pyrenean Experiment (campaign)

Q QinetiQ ........ New name of DERA (Defence Evaluation and Research Agency),

Farnborough, UK, pronounced as "kin-et-tik" (as of July 2, 2001) QMW .......... Queen Mary and Westfield College (London, UK)


QPN ........... Quadra Pseudo Noise (modulation technique) QPSK .......... Quadra-Phase Shift Keying ( 4-PSKis a modulation technique and ada

ta transmission standard). Soon 8-PSK and higher modulations for such applications as DBS (Digital Broadcast System) will be used.

QuickBird . . . . . . Commercial imaging satellite (B.4.2) QUT .......... Queensland University of Technology, Australia QWIP ......... Quantum Well Infrared Photodetector (for applications in the range

from 6-25 !AID)

R RADAR . . . . . . . Radio Detection and Ranging RADARSAT .... A Canadian (CSNCCRS) EO mission with a SAR instrument (D.29) RADCAL . . . . . . Radar Calibration Satellite (A microsatellite of USAF, launch June 25,

1993 from VAFB. It provides space-based radar cross-sectional area calibration for more than 70 radars operating in the C-band, and carries two GPS receivers with the aim to demonstrate GPS based attitude determination.)

RADFET ...... Radiation-sensitive Field Effect Transistor RAE ........... Royal Aerospace Establishment [Farnborough, UK, (in the early 1990s

RAE was renamed into 'DRA'- Defense Research Establishment)] RAIM ......... Receiver Autonomous Integrity Monitoring (a GPS and GLONASS

technology - RAIM requires a minimum of five visible satellites for fault detection and six satellites for fault detection and exclusion)

Rosaviakosmos .. Russian Aviation and Space Agency (RASA), Moscow. The name of Rosaviakosmos was adopted by decree (No 1186) on Oct. 25, 1999. The previous name was RKA (Russian Space Agency) which in turn was created Feb. 25, 1992.

RAL ........... Rutherford Appleton Laboratory (Chilton, Oxon, UK) RAM . . . . . . . . . . Random Access Memory RAN (RAS) .... Russian Academy of Sciences RASS .......... Radio-Acoustic Sounding System (a ground-based system of wind and

temperature vertical profiles is used in meteorology and atmospheric research).

RBDS . . . . . . . . . Radio Broadcast Data System RCVR . . . . . . . . . Receiver R&D . . . . . . . . . . Research & Development RDL ........... Research and Development Laboratories, Culver City, CA REBAL . . . . . . . . Radiation and Energy Balance for Imagery and Electromagnetic Prop-

agation (campaign) REFLEX . . . . . . . Radiation and Eddy Flux Experiment (campaign) REFLEX . . . . . . . Return Flux Experiment (Shuttle SPARTAN payload) REM .......... Release/Engage Mechanism (Shuttle, used for Spartan flights) RENE . . . . . . . . . Rehearsal ERS-1 Validation Northern Europe (campaign) RESTEC ....... Remote Sensing Technology Center, Tokyo, Japan (since 1975) Resource21 ..... Commercial imaging satellite (under development by Resourse21) Resurs ......... Russian satellite series for resource monitoring, D.31, D.32 RF (R/F) ....... Radio Frequency (of active sensors, also data transmission link, etc.) RFI . . . . . . . . . . . Radio Frequency Interference RGB .......... Red, Green, Blue (color code) RHCP ......... Right Hand Circular Polarization RICE .......... Regional Interactions of Climate and Ecosystems (IGBP/IGAC pro

gram) RIN ........... Royal Institute of Navigation (UK) RIRT (RIRV) . . . Russian Institute of Radionavigation and Time, St. Petersburg, since

1957 (before 1993 the institute was called: Leningrad Scientific andResearch Electro technical Institute); participation in programs: Tsikada, Glonass, Cospas-S&RSAT

1458

RIS ........... . RISDE ........ . RIT-10 ........ . RIT .......... . RITS ......... . RKA(RSA)

RKKEnergia


Resonance Ionization Spectroscopy (a laser technique) Russian Institute of Space Device Engineering Radio-frequency Ion Thruster (electric propulsion sytem of DASA) Royal Institute of Technology, Sweden Radiatively Important Trace Species (campaign) Russian Space Agency, Moscow, since Feb. 25, 1992 (by decree issued by the President of the Russian Federation). RKA has centralized con-trol of Russia's civilian space program, including all manned and unmanned nonmilitary space flights.- On Oct. 25, 1999, RKA changed its name officially to "Rosaviakosmos" (Russian Aviation and Space Agency).-- The prime contractor used by Rosaviakosmos is RKKEnergiya, which owns and operates the Mission Control Center in Kalinin-grad and operates the Mir space station. Rocket Space Corporation, Kaliningrad, Moscow region (also referred to as RSC, since 1946); responsibility for all Russian manned space projects; builders of launch vehicles (Proton) and of SIC (i.e. MIR space station), payloads, sensors, etc.

RLG ........... Ring Laser Gyroscope (an angular rate gyro) RLSBO ........ Radiolokazionnaja Sistema Bokowo Obzora (side view radar system) RME .......... Radiation Monitoring Experiment (Shuttle payload) RMS .......... Remote Manipulator System (robot arm of Shuttle) RMS . . . . . . . . . . Royal Meteorological Service (UK) RNII KP (ISDE) Russian Institute of Space Device Engineering, Moscow; a leading

company in the design and development of sensors; participation in programs: Venera, Vega, Phobos, Luna, Mars, Prognoz, Granat, Resurs, Okean, Glonass, etc.

ROCSat ........ Republic of China Satellite (Taiwan) ROIC .......... Readout Integrated Circuit (silicon device for readout of infrared de-

tector photodiodes) ROM .......... Read Only Memory ROMPS ........ Robot Operated Materials Processing System (Shuttle payload) ROSHYDROMET Committee for Hydrometeorology and Environmental Monitoring

ROTEX ....... . RSCC ......... . RSI ........... .

(Russian Government Agency, similar in functions and services to EUMETSAT and NOAA) Robotic Experiment (Shuttle experiment) Russian Satellite Communication Company (Moscow) Radarsat International Ltd. (Richmond, BC, Canada, established in 1989 by a consortium of Canadian aerospace companies and Lockheed Martin of USA, RSI is the distributor of Radarsat data)

RSIF .......... Rain-Sea Interaction Facility (at NASNGSFC!WFF, established in 1993; RSIF provides a controlled environment for studies of a) microwave scattering from rain-generated features, and b) physical processes at the air-water interface and in the adjacent boundary layers)

RSRE ......... Royal Signals and Radar Establishment (Great Malvern, Worcestershire, UK)

RTCA . . . . . . . . . Radio Technical Commission for Aeronautics (Washington, DC) RTCM SC-104 .. Radio Technical Commission for Maritime Services [the RTCM Spe

cial Committee 104 established the worldwide standard for meter-level differential GNSS (Global Navigation Satellite System) broadcasts]

RTG . . . . . . . . . . . Radioisotope Thermoelectric Generator (a nuclear propulsion system first flown on Transit -4A, also on Ulysses K.28). Deep space missions in particular depend on RTG propulsion

RTK ........... Real-Time Kinematic (a DGPS technique) RN (or RV) . . . . Research Vessel RVSN . . . . . . . . . . Russian Strategic Missile Force (agency responsible for launching most

of Russia's military satellites) RWS ........... Rijkswaterstaat (Rijswijk, Netherlands)


Rx/Tx . . . . . . . . . . Receiver/Transmitter

s S/A ............ Signal to Ambiguity ratio SA ............ Selective Availability (GPS) SAA ........... South Atlintic Anomaly SAAMD/WBSAAMD Stand Alone Accelleration Measurement Device/Wide Band

Stand Alone Acceleration Measurement Device (Shuttle payload) SAAMEX . . . . . . Surface & Atmospheric Airborne Microwave Experiment (campaign) SABLE ........ South Atlantic Backscatter Lidar Experiment (campaign) SAC/CSIR ...... Satellite Application Center [of CSIR (Council for Scientific and In

dustrial Research), South Africa]. The SAC ground receiving station (Landsat, Spot, NOAA/POES series, ERS series, Radarsat, etc.) is located at Hartebeesthoek south-west of Pretoria, South Africa. Initial SAC tracking services started in 1961.

SAFARI ........ Southern African Fire-Atmosphere Research Initiative (campaign) SAFER ........ Simplified Aid for EVA Rescue (Shuttle system) SAFIR ......... Satellite for Information Relay, C.5 SAFISY ........ Space Agency Forum for the International Space Year in Europe (in

1992) SAGA ......... Soviet-American Gases and Aerosols Experiment (campaign) SAGE ......... Stratospheric Aerosol and Gas Experiment (NASA mission, G.8) SAl ............ Space Applications Institute (of JRC, Ispra, Italy) SAl . . . . . . . . . . . . Spectrum Astra Inc. of Gibert, AZ SAIC .......... Science Applications International Corporation (HQs in San Diego,

CA, since 1969, with over 35,000 employees worldwide) SAIR . . . . . . . . . . Synthetic Aperture Interferometric Radiometer SALRO ........ Saudi Arabian Laser Ranging Observatory, located some 45 krn north

west of Riyadh, Saudi Arabia (tracking of SLR systems) SALSA ......... Semi-Arid Land-Surface-Atmospheric Program (campaign). The

SALSA program is a multi-agency, multi-national global-change research effort that seeks to evaluate the consequences of natural and human-induced changes in semi-arid environments.

SALT .......... Savannas on the Long Term (IGBP program of France) SALT .......... Strategic Arms Limitation Treaty (cold war agreement) SAM ........... Shuttle Activation Monitor (Shuttle experiment) SAMIR . . . . . . . . Satellite Microwave Radiometer (ISRO sensor on Bhaskara S/C) SAMPEX ...... Solar Anomalous and Magnetospheric Explorer (GSFC mission,

K.21.1) SAMS ......... Space Acceleration Measurement Systems (Shuttle experiment) SAMSO ........ Space and Missile System Organization (USAF in El Segundo, CA) SAN MARCO .. Cooperative Italian/NASA mission (A.25) SAO ........... Smithsonian Astrophysical Laboratory (Cambridge, MA, USA) SAR . . . . . . . . . . . Synthetic Aperture Radar (a high-rate imaging technique) SAREX-2 ...... Shuttle Amateur Radio Experiment (Shuttle payload) SAREX-92 ..... South American Radar Experiment (ESA airborne campaign) S&R ........... Search and Rescue (Emergency System on NOAA SIC) S&RSAT ....... Search and Rescue Satellite Aided Tracking System (Canada/France/

NOAA).I.6 SAS-1 . . . . . . . . . . Small Astronomy Satellite-I (DoD SIC, launched Dec. 12, 1970) SAS . . . . . . . . . . . Synthetic Aperture Sonar SAS&R ........ Satellite Aided Search & Rescue (INSAT-2 system) SASS .......... Subsonic Assessment (program, NASA) SaTReC ........ Satellite Technology Research Center (Taejon, Korea, since 1992, Sa

TRee is a university based research center of KAIST) SaTReC performs KITSAT operations, etc.


SatReCi ........ SaTReC Initiative (SaTReCi Co. Ltd was established in January, 2000 by former SaTReC engineers, Taejon, Korea)

SATO .......... Space Adaptation Tests and Observations (Shuttle experiment) SAXON-FPN ... Synthetic Aperture Radar and X-band Ocean Nonlinearities - For-

schungs.12latform Nordsee (campaign) Sb ............. Antimonide (detector type material) SBAS . . . . . . . . . . Satellite Based Augmentation System (element of GNSS) SBIR . . . . . . . . . . Small Business Innovation Research (a NASA-sponspred program) SBIRS ......... Space Based Infrared System (a US DoD 10-year development pro

gram that was approved in Oct. 1996 to include HEO/GEO and LEO satellite constellations along with a corresponding ground segment. The SBIRS mission is to develop, deploy, and to operate space-based surveillance systems for missile warning, missile defense, battlespace characterization, and technical intelligence). The SBIRS program office is at SMC, Los Angeles AFB, CA.

SBRC .......... Santa Barbara Research Center (of Hughes Aircraft Company in Goleta, CA - The name (SBRC) was valid until 1996; the facility was renamed to SBRS)

SBRS . . . . . . . . . . Santa Barbara Remote Sensing (of Hughes Aircraft Company in Goleta, CA, since 1996). Note: in Dec. 1997 Raytheon merged with the defense operations of Hughes Electronics. The merger outcome was the "Raytheon Systems Company" with HQ in Washington DC, consisting of the following units: Raytheon Electronic Systems, Raytheon E-Systems, Raytheon TI Systems and Hughes Aircraft Company. SBRS instruments include: multispectral imagers (MSS and TM), radiometers, spectrometers, polarimeters, and sounders.

SIC . . . . . . . . . . . . Spacecraft SCAPE . . . . . . . . Shenandoah Cloud and Photochemistry Experiment (campaign) SCAR ......... Smoke/Sulfates Clouds and Radiation (campaign) SCAR ......... Scientific Committee on Antarctic Research (of ICSU) SCARLET ..... Solar Concentrator Array with Refractive Linear Element Technology

(a patented solar cell technology of AEC-Able Engineering Co., Goleta, CA, sponsored by BMDO and NASA/LeRC)

SCATHA ....... Spacecraft Charging at High Altitude (satellite of the USAF) SCATT ........ (Wind) Scatterometer (ESA) SCCCAMP . . . . . South Central Coast Cooperative Aerometric Monitoring Program

(campaign) SCD . . . . . . . . . . . Swept Charge Detector SCD-1 ......... Satelite de Coleta de Dados (Data Collection Satellite of Brazil), C.6 SCE . . . . . . . . . . . Superconducting Electronics SCISAT/ACE ... Science Satellite/Atmospheric Chemistry Experiment, A.26 SCION ......... Southern California Integrated GPS Network SCMS ......... Small Cumulus Microphysics Study (campaign) SCOPE ........ San Clemente Ocean Probing Experiment (campaign) SCOPE ........ Scientific Committee on Problems of the Environment (ICSU) SCPS .......... Space Communications Protocol Standard (A standardization initia

tive by NASA, DoD, DERA and others with the objective to complement and expand the current CCSDS standards) Although the CCSDS packetised standards provide the underpinning for the automated, error-free exchange of data between space and ground stations, it is limited to basic data transfer. SCPS will provide the additional capability to aggregate both telecommand and telemetry data into recognisable files and transport them end-to-end through the data networks containing space links in a reliable and secure manner.

SCRS .......... Saudi Center of Remote Sensing, Riyadh, Saudi Arabia SCS ........... Soil Conservation Service (USA) SCSMEX . . . . . . . South China Sea Monsoon Experiment (campaign)


SEA CAT ....... type of buoy (made by Sea-Bird Electronics), temperature and conductivity sensor

SEADEX Shoreline Environment Atmospheric Dispersion Experiment (campaign)

SEAFIRE South-East Asia Fire Experiment (campaign) Sea Launch ..... A sea-going launch system, based at Long Beach, CA. Sea Launch is a

joint venture of The Boeing Commercial Space Co., Seattle, USA, KB Yuzhnoye/PO of Dnepropetrosvk, Ukraine (provider of the Zenit rocket), RSC Energia of Korolev, Russia (builder of an upper stage of the rocket), and Kvaerner Maritime NS, Lysaker, Norway and London, UK (builder of the self-propelled launch platform and the Sea Launch command and assembly ship). The Sea Launch venture was announced in June 1994. The first launch of a demonstration satellite with a Zenit-3SL rocket took place March 27, 1999 from the floating Sea Launch platform, positioned at the equator. Sea Launch has a capacity to put up to 5000 kg of launch mass into a geostationary transfer orbit (GTO).

Seasat .......... NASNJPL EO mission (D.35) SEASOAR ..... Towed profiling CTD and ADCP system (TOGNCOARE campaign) SeaStar ........ An ORBIMAGE mission with the SeaWiFS sensor (B.8.2). In 1997

OSC renamed the SeaStar mission to Orbview-2) SeaWiFS ....... Sea Wide Field Sensor (this sensor is considered the CZCS successor) SECAM ........ Sequential Color and Memory [European (French) video standard].

SECAM has an image format of 4:3, operating with 625 lines per picture frame at 50 Hz and 6 MHz video bandwidth with a total of 8 MHz video channel width.

SECDED ...... Single Error Correction - Double Error Detection SEDAC ........ Socio-Economic Data and Applications Center (DAAC at CIESIN) SEDIS . . . . . . . . . Sea WiFS European Data Information System (ESNESRIN) SEDS .......... Students for the Exploration and Development of Space (since 1980,

international student organization) SEE . . . . . . . . . . . Societe des Electriciens et des Electroniciens SEE ........... Space Environments and Effects program since 1995 [NASA (US gov

ernment, industry and university participants), also international participation]

SEEDS ........ Seeds in Space Experiment (Shuttle payload) SEH ........... Solar Extreme Ultraviolet Hitchhiker (Shuttle payload) SEI . . . . . . . . . . . . Space Electronics Inc., San Diego, CA SEL ........... Space Environment Laboratory (NOAA, Boulder CO, real-time pro

cessing of all SEM package data, space environment forecasts) SEL ........... Surface-Emitting Laser (a conventional diode laser with a horizontal

cavity, beams are emitted in the direction parallel to the wafer plane) SELODE ....... Solar Exposure to Laser Ordnance Device (Shuttle experiment on

SPARTAN) SEM ........... Space Environment Monitor (NOAA Sensor package on GOES and

POES series; Note: the GOES series SEM package arrangement differs considerably from the POES series SEM package)

SEM ........... Space Experiment Module (Shuttle structure for small experiments) SEMAPHORE .. Structure des Echanges Mer-Atmosphere, Proprietes des Heteroge

neites Oceaniques (French airborne campaign) SERC .......... Science and Engineering Research Council (UK, the Mullard Space

Science Laboratory of SERC) SERON ........ South Eastern (US) Regional Oxidant Network (field program to study

atmospheric chemistry, July-August 1991) SES ........... Saab-Ericsson Space, Sweden SES . . . . . . . . . . . Societe Europeenne des Satellites (Luxembourg, owner and operator

of the ASTRA satellite series)


SESAME ....... Second European Stratospheric Arctic and Midlatitude Experiment (campaign)

SESAME ....... Severe Environmental Storms and Mesoscale Experiment (campaign) SESO .......... Societe Europeenne de Systemes Optiques, (Aix en Provence, France) SET . . . . . . . . . . . Single Electron Transistor SETAS ......... Space Environments and Technology Archive System (NASNLaRC) SEU ........... Single Event Upset S&F ........... Store-and-Forward (a non-real-time communication technique) SFDU ......... Standard Format Data Unit (a CCSDS format concept) SGG . . . . . . . . . . . Satellite Gravity Gradiometry SGGM ......... Superconducting Gravity Gradiometer Mission, NASA (SGGM was

cancelled by NASA in the 1990s due to budget constraints) SGLS .......... Space-to-Ground Link System (satellite communications) SGS 85 ......... Soviet Geodetic System 1985 SGS ........... Svalbard Ground Station, located (78° N, 20° E) on the Norwegian

Svalbard archipelago (Spitzbergen is the largest island of the Svalbard archipelago) near the town of Longyearbyen, is owned by the Norwegian Space Center (Norsk Romsenter), Oslo, Norway, and operated by the Trams¢ Satellite Station. The high latitude makes SGS (just 960 km from the North Pole) a very sought-after link for polar-orbiting satellites. In 1999, NASA built its own receiving station (two 11m antennas in X- and S-band) right next to SGS (part of Lockheed's Consolidated Space Operations Contract) to receive data from Earth observing satellites (Landsat -7, Terra, etc.). -SGS can provide SIC contact for all orbits of polar orbiting satellites having altitudes above 500 km.

SHAR ......... SriharikotaRange (ISRO launch site, India) SHARE . . . . . . . . Space-Station Heat Pipe Advanced Radiator Experiment (Shuttle) SHEBA ........ Surface Heat Budget in the Arctic (campaign) SHELS . . . . . . . . Shuttle Hitchhiker Experiment Launch System SHF ........... Super High Frequency (3 - 30 GHz band) SHOM ......... Service Hydrographique et Oceanographique de Ia Marine (French

Naval Hydrographic and Oceanographic Service) since 1971, with HQ in Brest, France. SHOM is a public service and a defense support agency - providing science and technical services (data acquisition, bathymetry, cartography, geophysics, oceanography).

SHOOT ........ Super Fluid Helium On Orbit Transfer (Shuttle experiment) SHS . . . . . . . . . . . Spatial Heterodyne Spectroscopy Si ............. Silicon (detector material) SiAs . . . . . . . . . . . Arsenic-doped silicon detectors SiGa ........... Silicon gallium (detector) SI ............. Systeme International d'Units (International System of Units) SiC ............ Silicon carbide (example: SiC-type ceramic mirrors and structures are

components in opto-mechanical systems) SICH .......... Owl(inUkrainian,.see SICH-1 under OKEAN) SIL ............ Space fimoyatiorts Limited, Newburry, Berks, UK [founded in 1983,

since 1998 a subsidiary of SpaceDev Inc., San Diego, CA; SSTL (Surrey) purched SIL in 2000]

SIM . . . . . . . . . . . Space Interferometry Mission (NASA) SIMMS ........ Seasonal Sea Ice Monitoring and Modeling Site (campaign) SIMPLEX . . . . . . Shuttle Ionospheric Modification with Pulsed Local Exhaust (Shuttle

payload) SIO ............ Scripps Institution of Oceanography (part of UC at San Diego, La Jol

la, CA) SIPT . . . . . . . . . . . Societe Internationale de Photogrammetrie et de Teledetection SIR ............ Shuttle Imaging Radar (SIR-A with Payload A; SIR-B with Payload B,

etc.), see J.19- J.21 SIRTF ......... Space InfraRed Telescope Facility (NASA)


SIS ............ Superconductor-Insulator-Superconductor (tunnel junctions, also a microwave spectrometer receiver type)

SITe ........... Scientific Imaging Technologies Inc. (US company in Beaverton, OR, CCD imaging products)

SITP . . . . . . . . . . . Shanghai Institute of Technical Physics (of the Academy of Sciences of China), founded in 1958. Development of optical and infrared sensors since 1964 as well as radiometers.

SIZEX ......... Seasonal Ice Zone Experiment (campaign) SJ ............. Shi Jian (meaning "experiment" or "experimental"). A spin-stabilized

scientific minisatellite series of CAST, China; launch of SJ -1 on March 3, 1971; SJ-2 (2A and 2B) launch Sept. 19, 1981, SIC mass= 257 kg for each SIC (note: three satellites were launched by a single launch vehicle); SJ-41aunch on Feb. 8, 1994 (orbit: 210 km x 36125 km, inclination= 28.6°), SIC mass= 396 kg; SJ-51aunch on May 10, 1999

SKYLAB ....... Sky Laboratory, NASA Space Station of the 1970s (L.5) SL ............. Spacelab- a modular general purpose laboratory. An integral element

of NAS~s Space Shuttle Program provided by ESA (build by MBBI ERNO). Spacelab itself comprised several elements that could be mixed-and-matched to suit mission requirements. A typical launch mass of a Spacelab was in the order of about 10 tons. SL-1 totalled a PM (Pressurized Module) mass of 8,145 kg plus a Pallet mass of 3,386 kg (including 1392 kg of payload mass). Spacelab is the first European manned space project. A total of22 missions were flown with Spacelab starting with STS-9 (Nov. 28, 1983) until STS-90 (April17, 1998). The Spacelab program provided numerous investigators from many countries an opportunity, to fly their instruments. Experiments conducted were generally in the fields of Earth observation, astronomy, atmospheric physics, life sciences, and material sciences under microgravity conditions.

SLA ........... Shuttle Laser Altimeter (Shuttle payload) SLAR .......... Side-Looking Airborne Radar (an active sensor with Real Aperture

Radar technology) SLC . . . . . . . . . . . Satellite Launch Center (complex) SloshSat -FLEVO A small satellite of the Netherlands to study fluid dynamics in low gravi

ty with FLEVO (Facility for Liquid Experimentation and Verification in Orbit). Shuttle payload

SLR ........... Satellite Laser Ranging (a network of ground stations providing ser-vices of laser range measurements)

SLS ............ Space Life Sciences (Shuttle payload) SLS ............ Strained Layer Superlattice (infrared detector type) SMART . . . . . . . . Small Missions for Advanced Research in Technology (ESA Horizons

2000 mission) SMC ........... Space and Missile Systems Center, part of Air Force Materiel Com

mand, with HQs located at Los Angeles AFB, El Segundo, CA (since 1954). SMC has operating sites throughout the USA, including the operating location detachment at NAS~s Johnson Space Center, Houston, Texas; Detachment 2 at Onizuka Air Station in Sunnyvale, CA; and Detachment 9 at Vandenberg Air Force Base, CA. SMC is also the parent center of the host unit at Kirtland Air Force Base, Albuquerque, NM. SMC's work force totals over 9,500 employees. Some major programs of SMC are GPS/NAVSTAR, DMSP, SBIRS, etc.

SMCITE ....... Space and Missile Systems Center I Test & Evaluation Directorate. A tri-service (Army, Navy, Air Force) SIC division with locations at Kirtland AFB, Albuquerque, NM; Falcon AFB, Colorado Springs, CO; VAFB, Vandenberg, CA; Los Angeles AFB, El Segundo, CA; and at NASNJSC, Houston TX. SMC/TE was established in 1992.


SMC/TEL ...... Space and Missile Systems Center I Space and Missile Test Evaluation Directorate. The Air Force serves as the executive agent for the Space Test Program (STP).

SMCITEO ...... SMC I Orbital Telemetry, Tracking and Commanding Operations Division

SME ........... Solar Mesosphere Explorer (NASA, K.20) SMEX . . . . . . . . . Small Explorer Program (NASNGSFC program since 1988 supporting

disciplines in astrophysics, space physics and upper atmospheric science; SMEX missions are SAMPEX, FAST, SWAS, TOMS, etc.)

SMHI . . . . . . . . . . Sweriges Meteorologiska och Hydrologiska Institut (Swedish Meteo-rological and Hydrological Institute), Norrkoping

SMM . . . . . . . . . . Solar Maximum Mission (NASA,K.22) SMOS ......... Soil Moisture and Ocean Salinity (ESA mission, D.36) SMS . . . . . . . . . . . Synchronous Meteorological Satellite (designation of the first US

weather satellites (1974); this series was later renamed GOES (NOAA) SMTP . . . . . . . . . Simple Mail Transfer Protocol SNAP .......... Surrey Nanosatellite Applications Program (D.40.16) SNCMP ........ Service National des Champs Magnetique Pulses (Toulouse, France) SNL ........... Sandia National Laboratories (Albuquerque, NM- since 1945, and Liv

ermore CA, USA; SNL is part of DOE and operated by AT&T since 1949). Since Oct. 1, 1993, SNL ismanaged by Martin Marietta Corp., now Lockheed Martin. Part of SNL is now part of LANL.

SNOE ......... Student Nitric Oxide Explorer (N.17.1) SNR ........... Signal-to-Noise Ratio SNSB .......... Swedish National Space Board (RYDSTYRELSEN), Solna Sweden SOz . . . . . . . . . . . Sulphur dioxide S04 . . . . . . . . . . . Sulphur radical SOCC ......... Satellite Operations and Control Center (NOAA) SOCEX ........ Southern Ocean Cloud Experiment (campaign) SODAR ........ Sound Detection and Ranging (system) SOD ERN ...... Societe Anonyme d'Etudes et Realisations Nucleaires (French instru

ment company) SOFIA ......... Stratospheric Observatory For Infrared Astronomy (P.188). A cooper

ative NASA and DLR astronomy observatory. A Boeing 747-SP aircraft, a modified airliner, is the platform of SOFIA. Flights start in late 2002, long-term observations for up to 20 years are planned. The telescope of SOFIA, provided by DLR, has an effective diameter of 2.5 m. The mass of the telescope is 18,000 kg.

SOFIA ......... Surface of the Ocean, Fluxes and Interaction with the Atmosphere (campaign)

SOHO ......... Solar and Heliospheric Observatory (see K.23) SOl ............ Silicon-On-Insulator (thin film technology). In SOl devices the elec

tronic active layers are fabricated on the insulator layer, while in conventional bulk devices the active layers are fabricated on the silicon layer. SOl is the technology of choice for radiation-critical applications (immunity to single-event latch-up from high-energy particles).

SOLAR-A ...... ISAS Solar-Terrestrial Mission, K.24 SOLSE/LORE .. Shuttle Ozone Limb Sounding Experiment/Limb Ozone Retrieval Ex-

periment (Shuttle payload) SONEX ........ SASS Ozone and NOx Experiment (NASA campaign in planning) SOP ........... Special Observation Period (in campaigns) SOP ........... Standard of Practice (refering to those technologies which are main-

stream and in common use) SORCE ........ Solar Radiation and Climate Experiment, A.27 SOS ........... Southern Oxidants Study (campaign) SOUP ......... Solar Optical Universal Polarimeter (Spacelab-2 sensor)


SpaceDev ...... SpaceDev Inc. is a commercial company with HQ in Poway (San Diego), CA, offering fixed-price (deep-space) missions.

SPACEHAB .... A concept for commercially sponsored and procured payloads and services on Shuttle. SPACEHAB Inc., of Vienna, VA, has a NASA contract leasing Shuttle space on a commercial basis in the so-called 'Commercial Middeck Augmentation Module' (CMAM), a pressurized research lab owned by SPACEHAB® (an extension of the Shuttle orbiter middeck in the Shuttle cargo bay). SPACEHAB in turn sells its services, providing the needed support for commercial development of space payloads as well as physical and operational integration, and all services (training, etc.) for these payloads. Once in flight, SPACEHAB payloads are crew-tended on request. The SPACEHAB contract was awarded in Nov. 1990, the first SPACEHAB flight took place on STS-57 in June 1993. - SPACEHAB-1, -2 identifies also a series of Shuttle payloads.

SPACELAB Space Laboratory on NASA Shuttle missions (J.22- J.23) Space Imaging . . Space Imaging Inc. (since 1994) of Thornton, CO, acquired EO SAT in

1995 [distributor of IKONOS Imagery, ERS-l/2, JERS and Radarsat data (USA), global distributor of IRS-1C/D imagery]. The owners of Space Imaging are: LM, E-Systems (of Raytheon), Mitsubishi, Vander Horst (Singapore), Halla Heavy Industries (Korea).

SPADE ........ Stratospheric Photochemistry, Aerosols and Dynamics Experiment (campaign)

SPDM ......... Special Purpose Dextrous Manipulator SPAN .......... Space Physics Analysis Network (based on the DECnet protocol). [The

US- SPAN (NASA) service was discontinued at the end of1990; theESPAN (ESA) service will be continued]. SPAN permits user access to data archives. The successor of SPAN in the US is NSI (NASA Science Internet), a dual protocol (TCP/IP and DECnet) network.

SPARC ......... Stratospheric Processes and their Role in Climate (WCRP project, successor to STIB)

SPARTAN . . . . . . Shuttle Pointed Autonomous Research Tool for Astronomy (Shuttle). SPARTAN is a small free-flying vehicle (about 1 x 1.25 x 1.5 m) for a variety of experiments (managed by OAST)

SPAS . . . . . . . . . . Shuttle Pallet Satellite (a Shuttle retrievable free-flyer platform for payloads, SPAS was built by MBB), SPAS-1 on STS-7 in 1983, ASTROSPAS is a direct successor of SPAS, ASTRO-SPAS-1 on STS-51 in Sept. 1993

SPECTRA . . . . . . Surface Processes and Ecosystems Changes through Response Analysis (a proposed ESA Core Mission), in 2001 SPECTRA is the new name and successor of PRISM (Processes Research by an Imaging Space Mission), an instrument, and LSPIM (Land Surface Processes and Interactions Mission)

SPECTRE ...... Spectral Radiance Experiment (campaign) SPICE ......... Sensors Performance in Cloud Experiment (campaign) SPIE ........... Society of Photo-Optical Instrumentation Engineering (international) SPIE . . . . . . . . . . . Shuttle Plume Impingement Experiment SPIFEX . . . . . . . . Shuttle Plume Impingement Flight Experiment SPIN-2 ......... Space Information-2 Meter. SPIN-2 is a joint venture (company) ofln

terbranch Association SOVINFORMSPUTNIK (Moscow, Russia), Aerial Images, Inc. (Raleigh, NC), and Central Trading Systems, Inc., (Huntington Bay, NY). The objective is to market high-resolution panchromatic imagery data (2 m) of past Russian missions (Resurs-F series). See KFA-1000 camera system under RESURS-F (the camera is also known by the name KVR-1000).

SPORT ........ Small Payload Orbit Transfer (an AeroAstro concept) SPOT .......... Systeme Pour !'Observation de Ia Terre (French Earth Observing Satel

lite), (D.37) SPOT-IMAGE .. Spot data distributor (Toulouse, France, and Reston, VA, USA)


SPRE . . . . . . . . . . SPARTAN Packet Radio Experiment (an amateur radio experiment on Shuttle SPARTAN)

SPS ............ Standard Positioning Service (GPS) SPST . . . . . . . . . . Single Pole Single Throw (Switch) SPT ........... Stationary Plasma Thruster (method of electric on-orbit propulsion) SQUID ........ Superconducting Quantum Interference Device (detector type, most

sensitive device for magnetic field detection in particular with superconducting technology)

SQPSK ......... Staggered Quadrature Phase Shift Keying (modulation type) SRAM ......... Static Random Access Method SRB ........... Surface Radiation Budget (GEWEX project) SRC . . . . . . . . . . . Space Regatta Consortium (Konsorsium Kosmicheskaya regata) since

1990, the association is based on the premises of RSC Energia SRI ............ Stanford Research Institute (original designation, founded in 1946),

now: 'SRI International' at Menlo Park, CA. The institute separated from the University for legal reasons,- SRI International is a nonprofit organization funded by contract research. About 2700 employees.

SRI ............ Systeme de Reference Inertielle SRL ........... Space Radar Laboratory (Shuttle missions of SIR-C/X-SAR payloads) SRON ......... Space Research Organisation Netherlands (Stiching Ruimlteonder

zoek Nederland, Utrecht, Groningen- the Netherlands), since 1983, builder of scientific instruments (HXIS, SCIAMACHY, HIFI, etc.)

SRSC .......... Siberian Remote Sensing Center, Novosibirsk, Russia SRTC .......... Savannah River Technology Center (DOE facility in Aiken, SC, USA) SRTM ......... Shuttle Radar Topography Mission, 1.25 SS/CPMA ...... Spread Spectrum/Code Position Multiple Access (communication con-

cept) SSB . . . . . . . . . . . Single Sideband SSBUV ........ Shuttle Solar Backscatter Ultraviolet (Shuttle Experiment) SSC ........... Swedish Space Corporation (Solna, Sweden; a government-owned lim-

ited corporation under the Ministry of Industry, established in 1972) SSC ........... Stennis Space Center (a NASA center in Bay St. Louis, MS) SSCE .......... Solid Surface Combustion Experiment (Shuttle payload) SSDL .......... Space Systems Development Laboratory, since 1994 (at the Depart

ment of Aeronautics and Astronautics of Stanford University, Stanford, CA)

SSEOP ......... Space Shuttle Earth Observation Project SSH ........... Sea Surface Height (measured by satellite altimetry) SSI ............ Spaceport Systems International, operators of the commercial Califor

nia Spaceport at Vandenberg, CA SSIP ........... Shuttle Student Involvement Program SS/L ........... Space Systems/Lora!, Palo Alto, CA (major US builder of communica

tion satellites, consortium leader of Globalstar series, sensors, etc.) SSMA ......... Spread Spectrum Multiple Access (communication transmission tech

nique) Spread-spectrum modulation is emerging as the technology of choice to provide secure, interference-tolerant transmission.

SSM/I .......... Special Sensor Microwave/Image (US Department of Defense, US Air Force Sensor)

SSN ........... Space Surveillance Network (of the US Space Command, Colorado Springs, CO)

SSP . . . . . . . . . . . . Sub-Satellite Point SSPA .......... Solid-State Power Amplifier SSPM .......... Solid-State Photomultiplier (detector type) SSPP .......... Shuttle Small Payloads Project SSRMS ........ Space Shuttle Remote Manipulator Arm (since 1981, also referred to

as Canadarm), built by Spar Aerospace of Canada SSS . . . . . . . . . . . . Sea Surface Salinity


SST . . . . . . . . . . . Space Solar Telescope (planned Chinese satellite mission in LEO with a 1 m diameter telescope using a 2048 x 1024 CCD detector array)

SST ........... Satellite-to-Satellite Tracking (a technique employed with two or more SIC in various orbits for determining the Earth's gravity field)

SST . . . . . . . . . . . Sea Surface Temperature (a physical parameter derived from radiometer data)

SSTI . . . . . . . . . . . Small Spacecraft Technology Initiative (aN ASA program started in 94) SSTL .......... Surrey Satellite Technology Ltd (University of Surrey, UK). SSTL is a

commercial company whose principal shareholder is the University of Surrey. SSTL was set up in 1985 to provide a commercial outlet for the University's SIC engineering research.

SSU ........... Stratospheric Sounding Unit (UK sensor on NOAA SIC) STA ........... Science and Technology Agency (of Japan) STA ........... Space Transportation Association [Washington DC, In March 1998, a

NASA study on space tourism was released ("General Space Travel and Tourism"). In response to the report's findings, STA has created a new "Space Travel und Tourism Division" (under DOC coordination) to promote public and private space travel]

STABLE ....... Suppression of Transient Accelerations By Levitation Evaluation (Shuttle payload)

STADAN ....... Space Tracking and Data Acquisitions Network (NASA/GSFC) STALO ........ Stable Local Oscillator STARE ........ Southern Tropical Atlantic Regional Experiment (campaign) Starlette ........ CNES 'Solid Earth' mission, a passive satellite for geodetic studies with

SLR observations (E.19) STARLink ...... Satellite Telemetry and Return Link (ER-2 telemetry link, see P.80) STAR-LITE .... Spectrograph/Telescope for Astronomical Research (Shuttle payload) START ......... System for Analysis, Research and Training (WCRP, IGBP, HDP) State Center Priroda Moscow; Scientific and production enterprise for Earth remote

sensing, commercial distributor of imagery; participation in programs: Resurs-F1, -F2, Salyut, MIR

STC ........... Sensitive Time Control (SAR antenna parameter) STC . . . . . . . . . . . Star Tracker Camera STCUI-RAS .... Scientific Technological Center of Unique Instruments- Russian Acad-

emy of Sciences (Moscow) STDN ......... Standard Tracking and Data Network (NASA) STEDI ......... Student Explorer Demonstration Initiative (N.17) Stella .......... CNES experiment on-board Spot-3 for gravity field studies of the Earth

(E.20) STEP . . . . . . . . . . Satellite Test of the Equivalence Principle, an ESA/NASA program

proposal (1989). A MiniSTEP mission resulted due to economic constraints.

STEP .......... Science and Technology for Environmental Protection (CEC program) STEP .......... Solar-Terrestrial Energy Program (International Program) STEP .......... Space Test Experiment Platform (a minisatellite bus of TRW Inc. for

the DoD STP program) STEP .......... Stratosphere Troposphere Exchange Project (campaign) STERAO . . . . . . . Stratosphere-Troposphere Experiments: Radiation, Aerosols, and

Ozone (campaign) STEREO ....... Solar-Terrestrial Relations Observatory, K.26 STEX .......... Sensor Technology Experiment (Shuttle) STEX .......... Space Technology Experiment (USA, NRO satellite launched Oct. 3,

1998) STIB .......... Stratosphere Troposphere Interactions and the Biosphere (Program) STIS ........... Space Telescope Imaging Spectrograph (new Hubble sensor since Feb.

1997) STJ ............ Superconducting Tunnel Junction

1468 Appendix B: Acronyms and Abbreviations ------

STL-1 . . . . . . . . . . Space Tissue Loss-1 (Shuttle experiment) STOIC ......... Stratospheric Ozone Intercomparison Campaign STORM-FEST .. Stormscale Operational and Research Meteorology - Fronts Experi

ment Systems Test (campaign) SIP ........... Space Test Program [of DoD, the USAFmanagesSTP, since 1965;Asof

2001, SIP has flown more than 420 experiments on more than 130 missions (STEP, POAM-III on SPOT-4, FORTE, REX-II, ARGOS are some current missions of STP)]

SIP . . . . . . . . . . . Solar Terrestrial Probes (NASA program with such missions as TIMED, SOLAR-B, STEREO, MMS)

STP-1 .......... Space Test Payload-1 (Shuttle) STRAT . . . . . . . . Stratospheric Tracers of Atmospheric Transport (campaign) STREAM ...... Stratosphere and Troposphere Experiments by Aircraft Measurements

(campaign) SIS ........... Space Transport System (Shuttle) STSI ........... Space Telescope Science Institute (Washington DC, see AURA) STSP .......... Solar Terrestrial Science Program (ESA). STSP comprises the SOHO

and CLUSTER missions SUCCESS ...... Subsonic aircraft: Contrail and Clouds Effects Special Study (cam

paign) SUMMiT ....... Sandia Ultra-planar Multi-level MEMS Technology (a MEMS fabrica

tion process developed at Sandia National La bora tones, Albuquerque, NM)

SUNY ......... State University of New York (Albany, Binghamton, Brockport, Buffa-lo, Stony Brook, etc.)

SUPARCO . . . . . Space and Upper Atmosphere Research Commission (Pakistan) SURFSAT-1 .... Summer Undergraduate Research Fellowship Satellite (NASNJPL) SUVE ......... Solar Ultraviolet Experiment (Shuttle experiment) SVAT .......... Soil-Vegetation-Atmosphere Transfer (models) SVFE .......... Shuttle Vibration Forces Experiment (Shuttle payload on STS-90 and

STS-96) SVGA ......... Super Video Graphics Adapter SVHS .......... Super Video Home System (a tape recorder system) SVI . . . . . . . . . . . . Spectral Vegetation Index SVN ........... Satellite Vehicle NAVSTAR (a GPS series numbering system) SVS ........... Space Vision System (Shuttle camera system for ISS assembly) SWADE ........ Surface Wave Dynamics Experiment (campaign) SWAS ......... Submillimeter Wave Astronomy Satellite (NASNGSFC) SWIR .......... Short Wave Infrared (spectrum, from about 1.3 ~m to 3 ~m) SwRI .......... Southwest Research Institute (San Antonio, Texas, an independent,

nonprofit, applied research and development organization with more than 2,700 employees)

SWUIS ........ Southwest Ultraviolet Imaging System (Shuttle payload)

T TACAN ........ Tactical Air Communication and Navigation System (a navigation aid,

primary Shuttle navigation device for landing, TACAN navigation is provided for Shuttle within 300 miles of the landing site)

TAMEX ....... Taiwan Area Mesoscale Experiment (campaign) TANS .......... Trimble Advanced Navigation Sensor ('TANS Vector' is a solid state

GPS attitude-determination and position-location system) TAO ........... Tropical Atmospheric Ocean (TOGA campaign) TAS ........... Technology Applications and Science (Shuttle payload) TAS ........... Thallium Arsenic Selenide (Tl3AsSe3)

TBD ........... To be defined (or: To be determined) TCIPO ......... TOGNCOARE International Project Office (at UCAR, Boulder,

CO)


TCP/IP ......... Transmission Control Protocol/Interchange Protocol. TCP/IP represents a communication framwork for other protocols such as: email, FTP, HTTP, SSH (Secure Shell), voice over IP, other multimedia protocols, teleoperation of remote systems. Note: the TCP/IP represents two layers of protocol: the TCP part and the lower level IP part. IP deals with how the data gets routed around the network. TCP deals with making sure that all the packets arrive and are in the correct order. TCP implies a two-way connection and a higher level of communications overhead to assure that all the packets arrive and are in the correct order.

TCS ........... Thomson-CSF Semiconducteurs Specifiques, Orsay, France TCS ........... Trajectory Control Sensor (Shuttle payload) T&DR ......... Tracking and Data Relay (NOAA) TDI ........... Time Delay Integration (a cumulative exposure concept for CCD imag

ing) TDL ........... Tunable Diode Laser (spectrometer; TDLs are suited for detection of

trace gases by optical absorption) TDLAS ........ Tunable Diode Laser Absorption Spectrometer TDMA ......... Time Division Multiple Access TDRSS ........ Tracking and Data Relay Satellite System (NASA) TEA . . . . . . . . . . . Transverse Excitation Atmospheric (pressure) laser TEAMS . . . . . . . . Technology Experiments Advancing Missions in Space (Shutte) TEC . . . . . . . . . . . Thermoelectric Cooler TEC . . . . . . . . . . . Total Electron Content (of ionosphere) Technion ....... Israel Institute of Technology, Haifa, Israel TEMISAT ...... Telespazio Micro Satellite (see C.7) TeOz . . . . . . . . . . . Tellurium dioxide TerraServer ..... A joint venture of Aerial Images Inc., Raleigh, NC; Microsoft Corp.,

Redmond, WA; Compaq Computer Corp., Houston, TX; and Eastman Kodak Co., Rochester, NY. TerraServer is a commercial service of spaceborne and airborne imagery provision via internet. The imagery offered comes from a variety of sources (commercial and institutional).

TERRIERS . . . . Tomographic Experiment using Radioactive Recombinative Ionospheric EUV (STEDI mission, N.17.2)

TERS . . . . . . . . . . Tropical Earth Resources Satellite [a joint program conceived by the Netherlands (NIVR) and Indonesia (LAPAN) in 1985, the program got stalled after phase A because of a lack of funds]

TERSS ......... Tasmanian Earth Resources Satellite Station (Hobart, Australia) TES ........... Thermal Energy Storage (Shuttle payload) TES ........... Transition-Edge Sensor (calorimeter) TFOV . . . . . . . . . Total Field of View TGDF ......... Turbulent Gas-Jet Diffusion Flames (Shuttle Experiment) TIFF . . . . . . . . . . Tagged Image File Format (a raster format in pixel representation used

for scanned images) TIMED . . . . . . . . Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics

(A.28) TIP ............ TIROS (or Telemetry) Information Processor (on-board POES SIC,

also a downlink data stream of NOAA SIC) TIPPs .......... Trans-Ionospheric Pulse Pairs (These strange signals, observed on

ALEXIS, are the most intense radio sources from Earth which can be much stronger than typical lightning)

TIR ........... Thermal Infrared (spectrum, from 6 ~tm to about 14 ~tm) TIROS ......... Television and Infrared Observation Satellite (US Environmental/Me

teorological Remote Sensing Program; TIROS 1-10 = 1st generation, ESSA 1-9 = 2nd generation, ITOS (TIROS-M) = 3rd generation,)

TIROS-N ...... TIROS-NOAA (4th generation TIROS satellite series, starting with NOAA-6, -7, -8, etc.)


TKSC . . . . . . . . . . Tsukuba Space Center, located Tsukuba Scince City, Japan (since 1972)

TLD . . . . . . . . . . . Thermoluminescent Dosimeter (Shuttle payload) TLM . . . . . . . . . . . Telemetry TMA .......... Three Mirror Anastigmatic (telescope off-axis design method). Note:

the term 'anastigmatic' refers to lenses that are able to form approximately point images of target (object) points.

TMIBD . . . . . . . . Thermocapillary Migration and Interaction of Bubbles and Droplets (Spacelab experiment)

TMIP . . . . . . . . . . TeleMedicine Instrumentation Pack (Shuttle payload) TMSAT ........ Thai MicroSatellite, was renamed to Thai-Phutt (D.40.15) TNO/FEL ...... Netherlands Organization for Applied Scientific Research/Physics and

Electronics Laboratory (The Hague and Delft, The Netherlands) TNSC . . . . . . . . . . Tanegashima Space Center (NASDA:s launch site at Tanegashima Is-

land, Japan, located at 30.4° N, 131.0° E) TOA ........... Top-of-Atmosphere TOF ........... Time-of-Flight (measurement) TOGA ......... Tropical Oceans and Global Atmosphere Experiment (Program) TOGNCOARE . Tropical Oceans and Global Atmosphere Experiment I Coupled Ocean

Atmosphere Response Experiment TOGNTAO . . . . TOGNTropical Atmosphere-Ocean (array of wind and upper ocean

thermistor chain moorings in the Tropical Pacific) TOGAJWOCE .. TOGA/World Ocean Circulation Experiment TOMS ......... NASA missions (A.29) TOPEXIPoseidon Topography Experiment for Ocean Circulation (NASNCNES EO

Mission), E.21 TOS ........... TIROS Operational System (NOAA) TOYS .......... TIROS Operational Vertical Sounder (NOAA, a three instrument sys-

tem consisting of: HIRS-2; SSU; and the MSU) TPCE .......... Tank Pressure Control Equipment (Shuttle payload) TPF ........... Two Phase Flow (Shuttle payload) TPFLEX ....... Two-Phase Fluid Loop Experiment (Shuttle payload) TPFO .......... TOPEX/POSEIDON Follow-On (mission, was renamed to Jason) TRACE-A . . . . . . Transport and Atmospheric Chemistry near the Equator - Atlantic

(campaign) TRAG EX ...... Trace Gas Exchange: Mid-Latitude Terrestrial Ecosystems and Atmo

sphere (IGBPIIGAC program) TRANSHAB . . . . An inflatable system NASA is considering for use on the ISS starting in

2004 TREE ......... Tropical Rain-Forest Ecology Experiment (campaign) TREES ........ Tropical Ecosystem Environment Observation by Satellites (Joint

CEC, JRC and ESA program TRIAD ........ Transit-Improved DISCOS (US Navy SIC built by APL) H.6 TRMM ........ Tropical Rainfall Measuring Mission (NASA-NASDA Mission), A.31 TRSC . . . . . . . . . . Thailand Remote Sensing Center, Bangkok TRW . . . . . . . . . . Thompson, Ramo and Wooldridge [TRW Space & Electronics Group

is located at Redondo Beach, CA]. Manufacturer of communication satellites (TDRS, Odyssey series), military spacecraft (STEP, AXAF, etc.), and remote sensing satellites (Lewis, EOS/PM-1, TOMS/EP, KOMPSAT-1, ROCSat-1, etc.)

TSI . . . . . . . . . . . . Total Solar Irradiance TSIM . . . . . . . . . . Total Solar Irradiance Mission TsNIIMASH .... Central Research and Scientific Institute of Machine Building, Korelev

(Moscow Region), Russia (there is also the spelling of TzNIIMASH) TsSKB-Progress . the Russian acronym for "Central Specialized Design Bureau Prog

ress," Samara, builder of Resurs-F (and Resurs-RK) satellite series TSS-lR ........ Tethered Satellite System (ASI payload on Shuttle)


TT &C ......... Telemetry, Tracking & Command (Data for S/C Operations) TTFM . . . . . . . . . Two-Tone Frequency Modulation (a measurement technique for trace

gases) TTL ........... Transistor-Transistor Logic (semiconductor technology of the 1960s

and 1970s- the microprocessor revolution began in 1973) TUB ........... Technical University of Berlin, Germany TUBSAT ....... Technical University of Berlin Satellite (N.21) TUD .......... Technical University of Denmark (Lyngby, Denmark) TUFI .......... Toughened Uni-Piece Fibrous Insulation (Shuttle payload) TVA ........... Tennessee Valley Authority (USA) TWTA ......... Traveling Wave Tube Amplifier (communication, amplification of ami

crowave frequency)

u UAH .......... University of Alabama in Huntsville, AL UARP ......... Upper Atmospheric Research Program (NASA) UARS . . . . . . . . . Upper Atmosphere Research Satellite (NASA satellite, launch: Sept.

1991) A.32 UAV ........... Unmanned Aerial Vehicle (PERSEUS, CONDOR, etc.) UC ............ University of California [a nine campus university across the state,

UCLA (Los Angeles), UCB (Berkeley), UCSD (San Diego), UCSB (Santa Barbara), UCI (Irvine), UCR (Riverside), UCSC (Santa Cruz), UCD (Davis), etc.]

UCAR ......... University Corporation for Atmospheric Research (Boulder, CO, UCAR is sponsored by NSF- there are over 60 member institutions in UCAR)

UCB ........... University of California, Berkeley UCCS ......... University of Colorado at Colorado Springs UCLA ......... University of California, Los Angeles UDP/IP ........ User Datagram Protocol/Internet Protocol. Note: UDP/IP does not

need any handshaking to transfer data. TCP/IP requires bi-directional handshaking prior to data transfer.

UHB .......... User Home Base UHF . . . . . . . . . . Ultra High Frequency (300 - 3000 MHz band) UIT ........... Ultraviolet Imaging Telescope (part of ASTR0-1 payload on Shuttle) UIT ........... Union Internationale des Telecommunications UKAEA ....... United Kingdom Atomic Energy Authority UKDoE ........ United Kingdom Department of the Environment UKMO ........ United Kingdom Meteorological Office (same as BMO, HQs and

Hadley Centre for Climate Prediction & Research are located in Bracknell, Remote Sensing Instrumentation branch in Farnborough)

UKS ........... United Kingdom Subsatellite (SIC of the AMPTE mission, K.4.2) ULIRGs ....... Ultra-Luminous IR Galaxies UMTS ......... Universal Mobile Telecommunications System (standard) UNAM ........ Universidad Nacional Aut6noma de Mexico, Mexico City UNAM-CE ..... Universidad Nacional Aut6noma de Mexico- Centro de Ecologica,

Mexico UNAM-IG ..... Universidad Nacional Aut6noma de Mexico- Institoto de Geologica UNAVCO ...... University Navstar Consortium (a US Earth sciences community initia-

tive to foster GPS applications in particular in the area of surveying) UNCED ....... United Nations Conference on Environment & Development UNDP ......... United Nations Development Programme UNAVCO ...... University NAVSTAR Consortium (USA) UNCOPUOS ... UN Committee on the Peaceful Uses of Outer Space UNEP ......... United Nations Environmental Programme (since 1972) UNEP/GRID ... UNEP Global Resource Information Database


UNESCO ...... United Nations Educational Scientific and Cultural Organization (based in Paris, France)

UN-ESCAP ..... UN-Economic and Social Commission for Asia and the Pacific, Bangkok, Thailand

UnESS ......... University Earth System Science (a NASA initiative with the objective to involve the student community in Earth science projects)

UNEX ......... University-class Explorer [(mission) -A NASA program supporting university-designed/developed missions. The UNEX program is designed to provide frequent flight opportunities for highly focused and relatively inexpensive science missions whose total cost to NASA is limited to $13 million. The program is managed by NASNGSFC]

UNH .......... University of New Hampshire, Durham, NH UNISPACE ..... United Nations Conference on the Exploration of the Committee on

the Peaceful Uses of Outer Space (UNISPACE-III took place in Vienna, Austria (July 19-30, 1999 -the first two UNISPACE conferences were held in 1968 and 1982)

UNOLS ........ University National Oceanographic Laboratory System (USA) UNS ........... Universal Navigation System UNOOSA ...... United Nations Office for Outer Space Affairs UoSAT ......... University of Surrey Satellite (UK, D.40) UPC ........... Universidad Politecnica de Barcelona (Spain) UQPSK ........ Unbalanced Quadrature Phase-Shift Keying (technique) URE .......... User Range Error (of GPS position service) URL ........... Uniform Resource Locator (WWW) for 'file:', 'http:', 'news:', and 'tel

net:' URSI .......... Union Radio Scientifique Internationale (International Union of Ra

dio Science) USA ........... United States of America USA ........... United Space Alliance LLC [of Houston, TX, a joint venture of Rock

well International (now The Boeing Company) and Lockheed Martin]USA is the NASA prime contractor for all Space Shuttle operations/ management at MSFC and at KSC, since Oct. 1996)

USACE . . . . . . . . US Army Corps of Engineers USAF . . . . . . . . . . US Air Force USAFA ........ United States Air Force Academy (Colorado Springs, CO) USAFB . . . . . . . . US Air Force Base USAF/PL ....... USAF/Phillips Laboratory, Kirtland AFB, Albuquerque, NM [part of

AFRL (Air Force Research Laboratory), note: in 1998 the Phillips Laboratory was renamed: "Phillips Research Site"]

USAF/RL ...... USAF/Rome Laboratory, Griffis AFB, Rome, NY [part of AFRL] USAF/SMC ..... USAF/Space & Missile Systems Center (see SMC/TE) USCG . . . . . . . . . US Coast Guard USCON-CICTUS Universidad de Sonora- Centro de Investigaciones Cientificas y Tecno-

logicas de Ia Universidad de Sonora, Hermosillo, Mexico USDA . . . . . . . . . US Department of Agriculture USDNARS .... USDNAgricultural Research Service (Beltsville, MD and Tucson, AZ) US EPA . . . . . . . . US Environmental Protection Agency USES .......... Universal Source Encoder for Space (a NASA developed chipset) USFS . . . . . . . . . . US Forest Service USFWS . . . . . . . . US Fish and Wildlife Service USGCRP ...... US Global Change Research Program (since 1990). USGCRP spon

sors global change research in a large number of institutions (over 300). USGS .......... United States Geological Survey (the science and technology agency of

the Department of the Interior, DOl; USGS was established in 1879). The mission of USGS is to provide geologic, topographic, and hydrographic information to contribute to the management of the Nation's natural resources.


USML . . . . . . . . . US Microgravity Laboratory (Shuttle payload) USMP ......... US Microgravity Payload (Shuttle payload) USRA ......... Universities Space Research Association, Columbia, MD [a nonprofit

corporation organized in 1969 by NAS (National Academy of Sciences) at the request of NASA; as of 1995 there are 78 member universities]

USS ........... Unique Support Structure (Shuttle) USSR .......... Union of Soviet Socialist Republics (former) USU/SDL ...... Utah State University I Space Dynamics Laboratory (Logan, UT, Bed

ford, MA, and Albuquerque, NM). SDL is a non-profit organization owned by USU.

USWRP . . . . . . . . US Weather Research Program UTA ........... University of Texas at Austin UTNCSR ...... UTNCenter for Space Research (since 1981) UTC ........... Universal Time Coordinated UTM .......... Universal Transverse Mercator (coordinate reference system for large

scale maps) UV ............ Ultra Violet (spectral range from 0.01 - 0.38 !J.m) UVCS ......... Ultrviolet Coronal Spectrometer (a SAO instrument flown on the

SPARTAN-201 series) UVPI .......... Ultraviolet Plume Instrument (Shuttle experiment) UVSTAR ....... Ultraviolet Spectrograph Telescope for Astronomical Research

(Shuttle payload) UWB .......... Ultra Wideband (involves multi-octave frequency coverage of a sensor

such as a radar system for the purpose of ground penetration)

v VAFB .......... Vandenberg Air Force Base, Vandenberg, CA VCL ........... Vegetation Canopy Lidar Mission, D.39 VCO .......... Voltage Controlled Oscillator VCR ........... Video Cassette Recorder (also: Video Color Recorder) VCS ........... Voice Command System (Shuttle) VCSEL ........ Vertical Cavity Surface-Emitting Laser (type of semiconductor diode

laser; the cavity is perpendicular to the wafer plane, thus the optical beam is guided in the vertical direction)

VDA .......... VHF Collection System Antenna (NOAA) VDC .......... Volt Direct Current VENTEX ...... Venting Experiment (campaign) VFT-1 ......... Visual Function Tester-1 (Shuttle experiment) VH . . . . . . . . . . . . Vertical transmit - Horizontal receive polarization VHF ........... Very High Frequency (30 - 300 MHz band) VHS . . . . . . . . . . . Video Home System VI . . . . . . . . . . . . . Vegetation Index Viking ......... Swedish satellite mission for the study of the Earth's magnetosphere,

K.29 VIR . . . . . . . . . . . Visible Infrared (spectrum) VIS ............ Visible (spectrum 0.4-0.7 !J.m) VITA .......... Volunteers in Technical Assistance (a humanitarian organization in Ar

lington, VA, USA, providing communication services on a global scale) VITO .......... Vlaamse ins telling voor technologisch onderzoek (Flemish institute for

technological research), located in northern Belgium. One of its centers is the image processing/archiving center of the VEGETATION instrument on SPOT.

VLBI . . . . . . . . . . Very Long Baseline Interferometry VLDS ......... Very Large Data Store VLF ........... Very Low Frequency (frequency band of 10-30kHz) VLS ........... Veiculo Lancador de Satellites (Brazil's launch vehicle) VLSI .......... Very Large Scale Integration (solid-state technology)


VLWIR ........ Very Long Wavelength Infrared (14-30 I-tm) VME .......... Versatile Multi-bus Extension (computer) VNIIEM .. ..... A11-Russian Scientific and Research Institute of Electromechanics

(Moscow; S/C builder/integrator, Meteor series, Okean series, Resurs series, GOMS, etc. also referred to as: NPP VNIIEM). Background: the enterprise was funded in 1941, in 1944 it was named "Science and Research Institute #627" or NII-627. In 1953, NII-627 was renamed to VNIIEM. In the early 1960s, VNIIEM began to develop meteorological spacecraft, using an innovative electromechanical stabilization system. - In Nov. 1992, the Istra Branch of VNIIEM separated to become an independent enterprise, NIl of Electromechanics (NIIEM). Since May 1998, VNIIEM reports to the Russian Space Agency (RKA).

VNIR .... .. .... Visible Near Infrared (spectral range 0.4 - 1.3 I-tm) VOC . .. ....... Volatile Organic (carbon) Compounds VORTEX . ..... Verification of the Origins of Rotation in Tornados Experiment (cam-

paign) VORTEX . ..... Vortex Ring Transit Experiment (G-93R Shuttle payload on STS-88) VOXEL . . . . . . .. Volume Element VPN . . . . . . . . . .. Virtual Private Network VRA .......... VHF Realtime Antenna (NOAA) VRAM ......... Video RAM VRTE ......... Vented Tank Resupply Experiment (Shuttle payload) VSAT . . . . . . . . .. Very Small Aperture Terminal (small ground antenna for satellite com-

munication) VSWR . . . . . . . .. Voltage Standing Wave Ratio VT . ..... . ..... Virtual Terminal VTT ........... Technical Research Center of Finland, (Espoo, Helsinki, Finland) VV ......... .. . Vertical transmit - Vertical receive polarization

w W AAS ......... Wide Area Augmentation System (FAA). W AAS is the US space-based

augmentation system that provides DGPS service over a very large geographical area (USA) by using a satellite broadcast of separate corrections for GPS dock, orbital data and ionospheric delay.

WAC .......... Wide-Angle Camera WADGPS ...... Wide Area Differential GPS WAlS .... . . . ... West Antarctic Ice Sheet Project (campaign) WARC . . .. .. .. . World Administrative Radio Conference (of ITU) WATS ......... Water-Vapor and Wind in Atmospheric Troposhere and Stratosphere

(a proposed ESA mission as of 2001) WAU ... ..... .. Wageningen Agricultural University, The Netherlands WBVTR ....... Wideband Video Tape Recorder (on Landsat-l to -3 series) WCASP ........ World Climate Applications and Services Programme (WMO) WCC .......... World Climate Conference (WCC-l in 1979, WCC-2 in 1990) WCDMP . .. . . .. World Climate Data and Monitoring Programme (WMO) WCIRP .. .. .... World Climate Impact Assessment and Response Strategies Pro

gramme (UNEP) WCP .... . ..... World Climate Program (WMO is the lead agency of WCP) WCRP ......... World Climate Research Programme (since 1980,jointly sponsored by

WMO, ICSU, and IOC) WDC ......... , World Data Center WDCGG . . ..... World Data Centerfor Greenhouse Gases (ofWMO) WDM .......... Wavelength Division Multiplexing (optical high-rate transisson

technology) WEFAX ........ Weather Facsimile (NOAA broadcast service of GOES S/C; transmis

sion of environmental data in WEFAX format to ground stations) WENPEX ... ... Western North Pacific Cloud-Radiation Experiment (campaign)


WESTEX ...... West Co ast Ship Tracks Experiment (campaign) WEU .......... Western European Union (with HQ in Brussels; WEU has 10 member

states: Belgium, France, Germany, Greece, Italy, Luxembourg, Netherlands, Portugal, Spain, and UK)

WFF ........... Wallops Flight Facility (of NASNGSFC, founded in 1945 by NACA) WFOV ......... Wide Field of View (of a sensor) WGS-84 ........ World Geodetic System - 1984 (DoD reference ellipsoid for GPS, etc.

GPS positions are computed in WGS-84, the system has been adopted internationally as the single worldwide datum for marine navigation)

WHRC ......... Woods Hole Research Center (Woods Hole, MA, USA) WHOI ......... Woods Hole Oceanographic Institution, (Woods Hole, MA, USA - a

marine science non-profit research facility founded in 1930) WIND ......... NASNGSFC Solar-Terrestrial Mission (K.30) WiNDEX ...... Window Experiment (Shuttle) WINDOS ...... Western Indian Ocean Study (campaign) WISP .......... Winter Icing and Storms Project (campaign) WL ............ Werkstofflabor (materials laboratory on Shuttle D2 mission) WLC .......... White Light Coronograph (instrument flown on SPARTAN-201 series) WMO .......... World Meteorological Organization (an agency ofthe United Nations,

located in Geneva, Switzerland, since 1951). Major science and technical programs of WMO are: WWW (World Weather Watch), WCRP (World Climate Research Program), GAW (Global Atmosphere Watch), HWRP gHydrology and Water Resources Program), GCOS (Global Climate bserving System), GOOS (Global Ocean Observing System)

WMSCC ....... World Meteorological Service Computing Center WOCE ......... World Ocean Circulation Experiment (Program) WPLTN ........ Western Pacific Laser Tracking Network (a ground network for SLR in

the Pacific region) WPTLN coordinates the activities of SLR stations in China, Japan, Australia, and Eastern Russia.

WRC .......... World Radiocommunication Conference (of ITU, Geneva, Switzerland, see also WARC)

WRMC ........ World Radiation Monitoring Center (Zürich, Switzerland) WRS .......... Worldwide Reference System (a global indexing scheme ofthe Landsat

program wh ich is based on nominal scene centers defined by path and row coordinates)

WSF ........... Wake Shield Facility (Shuttle payload, a retrievable platform) WSMC ......... Western Space and Missile Center (of USAF at Vandenberg, CA) WSTF ......... White Sands Test Facility (White Sands, NM), a facility of NASNJSC WUPPE . . . . . . .. Wisconsin Ultraviolet Photo Polarimeter Experiment (part of AS-

TRO-1 payload on Shuttle) WV ........... Water Vapor (in the 5.7 - 7.1 Ilm water vapor absorption band) WWW ......... World Weather Watch (WMO Program) WWW ......... World Wide Web (a wide-area dient/server architecture for exchanging

hypermedia across the Internet network). WWW offers platform independence and the use of different communication protocols, such as:

XeCl .......... . XIPS ......... .

XML

XMM ......... .

FTP (File Transfer Protocol), HTTP (HyperText Transfer Protocol), and SMTP (SimpleMail Transfer Protocol).

x Xenon Chloride laser Xenon Ion Propulsion System (on platform HS702 of Hughes Space and Communications Company, Los Angeles, CA) eXtensible Markup Language (a document markup language for the creation of hierarchical information structures) X-Ray Multi-Mirror Mission (of ESA). Note: XMM was officially renamed to "XMM-Newton" in Feb. 2000


XPD ........... X-ray Photoelectron Detection XRT ........... X-Ray Telescope (Spacelab-2 sensor, energy_ldetection 2.5-25 keY) XSS ........... Experimental Spacecraft System (US AFRI.Jminisatellite series) XTI . . . . . . . . . . . Cross-Track Interferometry XTR . . . . . . . . . . . Transmitter XUV . . . . . . . . . . Extreme Ultra Violet (same as EUV, i.e. 1 - 130 nm spectral range)

y

YAG ........... Yttrium Aluminum Garnet (a type of solid-state crystal laser) YBCO ......... Yttrium-Barium-Copper-Oxide (YBa2Cu307) YBLCO ........ Yttrium-Barium-Lanthanum-Copper-Oxide YLF ........... Yttrium Lithium Fluoride (a laser type) YUZHNOYE ... Research and Production Association, Dnepropetrosvk, Ukraine

(there is also the spelling of YUZHNOE- builders of two launch vehicles: Zenit and Cyclone; builders of OKEAN series satellites)

z ZAMG ......... Zentralanstalt fiir Meteorologie und Geodynamik, with HQs at Vien

na, Austria, since 1851 (Austrian Institute for Meteorology and Geodynamics)

ZARM . . . . . . . . . Zentrum fiir angewandte Raumfahrttechnologie und Mikrogravitation (Center of Applied Space Technology and Microgravity - since 1985), an institute of the University of Bremen, Germany

ZUP . . . . . . . . . . . Flight Control Center, Kaliningrad, Russia (TT &C function for MIR station along with RKK Energia)

Appendix C Index of Sensors

Numbers 3D-Electron Analyzer, 875

3D-Ion Analyzer, 875

3D-Plasma Analyzer, 897

A AA3500 = Airborne Bispectral Scanner

(ABS), 1612

AADS1220 =Dual Channel Terrain Surveillance Scanner, 1611

AADS1221 = Maritime Surveillance Scanner, 1611

AADS1230 = Dual Channel Quantitative Infrared Scanner, 1611

AADS1250 = Eleven Channel Analog Multispectral System, 1612

AADS1260 =Daedalus Multispectral Scanner (predecessor of ATM), 1609

AADS1268 = ATM (Airborne Thematic Mapper), 1609

AADS1278 = ATMX (ATM extended), 1609

AADS1280 =Daedalus Multispectral Scanner, 1609

AAHIS = Advanced Airborne Hyperspectral Imaging Spectrometer, 23, 1513

AAMAS (Aircraft-borne Automatic Mass Spectrometer), 1514, 1913, 1914

AARGOS (A340 Atmospheric Research Global Observation System), 1571

AAS = Airborne ASTER Simulator, 23, 1666

AATSR = Advanced Along Track Scanning Radiometer, 358, 370

ABI (Advanced Baseline Imager), 627

ABLE (Airborne Lidar Experiment), 1550

AC = Actinometric instrument (radiation budget sensor), 700

AC = Radiation Budget Sensor, 693

AC-ITMS (Air Concentrator-Ion Trap Mass Spectrometer), 1542

ACAP = Airborne Counter of Aerosol Particles, 1553

Accelerometer Testbed, 1160 ACCESS (Advanced Cosmic-Ray Com

position Experiment for Space Station) , 985

ACCESS (All Composite Experiment Spacecraft Structure), 1136

ACE-FTS (ACE-Fourier Transform Spectrometer), 236

ACES (Atomic Clock Ensemble in Space), 986

ACH = Aircraft Condensation Hygrometer, 1553

ACRIM = Active Cavity Radiometer Irradiance Monitor, 118, 119, 167, 262, 822,953

ACS (Advanced Composite Structure), 1048

ADACS (Attitude Determination and Control Subsystem), 228

ADAM (Advanced Data Acquisition and Messaging System), 435, 1043

ADC =Airborne Digital Camera, 1619

ADOLAR = Airborne Doppler Lidar, 1623

ADS = Analyzer of Dynamic Spectra, 929 ADTS (Advanced Detection Technology

Sensor), 1729 AEPI = Atmospheric Emissions Photo

metric Imaging Experiment, 823 AERCam (Autonomous EVA Robotic

Camera), 144 Aerosol Experiment, 1518, 1625 AES = Airborne Emission Spectrometer,

53, 1520, 1907

AFA-41!10 (Aerial Foto Apparatus), 1824

AFA-41!20 =Aerial Foto Apparatus, 1774

AFF (Autonomous Formation Flying), 91 AGEMA Thermal Imager, 1540 AHS = Airborne Hyperspectral Scanner,

23, 1618

1478 Appendix C Index of Sensors

AHSTRA (Airborne Heterodyne Spectrometer THz Astronomy), 1520

AIMR = Airborne Imaging Microwave Radiometer, 1521

AIMS-1000 (Airborne Imaging Mapping and Surveillance System), 1522

AirCam, 1522

AIRDAS = Airborne Disaster Assessment System, 1523

AIRES (Airborne InfraRed Echelle Spectrometer), 1806

Airglow Instrument (SME), 944

AIRS (Atmospheric Infrared Sounder), 376,387

AIRSAR =Airborne SAR, 31, 1525, 1864, 1880, 1884, 1890, 1894, 1908

AIS = Airborne Imaging Spectrometer, 23, 1529

AISA = Airborne Imaging Spectrometer for different Applications, 23, 1529, 1892

AKR-2 = Analyzer of Kilometric Radiation, 930

AKS = Aerial Krypton Sampler, 1542

ALADIN (Atmospheric Laser Doppler Instrument), 171

ALADIN =Atmospheric Laser and Doppler Instrument, 1255

ALAE = Atmospheric Lyman-Alpha Emissions, 823

ALAS = Airborne Laser Altimeter System, 1531

ALCOR (ARPA, Lindon Laboratory, Cband, Observables Radar), 30

ALEX = Aerosol Lidar Experiment, 1621, 1865, 1882

ALEXIS= Array of Low Energy X-Ray Imaging Sensors, 870

ALF = Airborne Laser Fluorosensor, 1532

ALI (Advanced Land Imager), 17, 21, 26, 91, 1026

ALIAS = Aircraft Laser Infrared Absorption Spectrometer, 1534, 1850, 1907

ALIAS-I on ER-2 Aircraft, 1534, 1895

ALIAS-II on Perseus Aircraft, 1534, 1763

ALISSA= !'Atmosphere par Lldar Sur SA!iout, 482, 1000, 1255

ALPHA-1, -2 (Airborne Lidar Plume and Haze Analyzer), 1809

ALPHA-3 = Ion Trap Experiment, 928, 929

ALPS = Airborne Laser Polarization Sensor, 1535

ALSE (Apollo Lunar Sounder Experiment), 29

Altimeter, further considerations, 358, 405,572,602,1917

ALTM = Airborne Laser Terrain Mapping, 1536

AMAP (Airborne Microwave Altimeter Platform), 1576

AMAS =Advanced Millimeter-Wave Atmospheric Sounder, 1309

AMEI-2 = Energy-Mass Analyzer, 929 AMI = Active Microwave Instrument, 30,

400, 1877, 1881, 1892, 1897, 1903, 1917

further considerations, 407 AMI-SCAT= Active MW Instrument

Scatterometer (ERS-1 ), 401

AMIE (Asteroid Moon micro-Imager Experiment), 1108

AMMR = Airborne Multichannel Microwave Radiometer, 1537, 1917

AMMS = Airborne Microwave Moisture Sounder, 1537, 1917

AMPR =Advanced Microwave Precipitation Radiometer, 1537, 1854, 1855, 1917

AMPS (Airborne Multisensor Pod System), 1538

AMR = Airborne Microwave Radiometer, 1692

AMS (Alpha Magnetic Spectrometer), 986

AMS =Airborne Multispectral Scanner, 1541, 1597, 1614

AMSOS (Airborne Millimeter & Submillimeter-wave Observing System), 1543

AMSR = Advanced Microwave Scanning Radiometer, 336

AMSR-E (Advanced Microwave Scanning Radiometer-EOS), 389

Appendix C Index of Sensors 1479

AMSS (Advanced MultiSpectral Scanner), 1693

AMSS MK-11 (Airborne Multi-Spectral Scanner), 23, 1544

AMSU (Advanced Microwave Sounding Unit), 388, 750

AMSU-A =Advanced Microwave Sounding Unit -A, 388, 681, 750

AMSU-B =Advanced Microwave Sounding Unit - B, 751, 1869

ANAPURNA = Energy and Pitch Distribution Experiment, 867

AOCI = Airborne Ocean Color Imager Spectrometer, 1609, 1613, 1614

AOE (Atomic Oxygen Experiment), 1112 AOE-2 (Atomic Oxygen Experiment-2),

1116

AOL = Airborne Oceanographic Lidar, 1545

AOS (Acousto-Optical Spectrometer), 1817

AP (Auroral Photometer), 1172 APDOR-95 (Airborne Polarimetric

Doppler Radar), 1545, 1920 APE (Airborne Polar Experiment), 1546 APEX (Alpha, Proton and Electronics

Experiment), 210

APT (Automatic Picture Transmission), 725, 728, 1077, 1078

ARAEX (Autonomous Remote Agent Experiment), 1023

ARES = Airborne Remote Earth Sensing, 23, 1559

ARGOS = Remote Data Collection System,681, 736,747,754

ARGOS/ADCS (Advanced Data Collection System), 681, 688

ARGUS (Two-Channel Atmospheric Tracer Instrument), 1561, 1763

ARIAS (Airborne Remote-Sensing & InSitu Aerosol Measuring System), 1548

ARISS (Amateur Radio on the International Space Station), 986

ARL (Airborne Raman Lidar), 1563, 1918

ARMAR = Airborne Rain Mapping Radar, 1564, 1917

ARP (ATV Rendezvous Pre-development), 787

ARP (ATV Rendezvous Predevelopment), 819

ASAR = Advanced SAR (ESA sensor), 358,363,1765

ASAS = Advanced Solid-State Array Spectrometer, 23, 1566

ASAS = Advanced Solid-State Array Spectroradiometer, 1565, 1853, 1854, 1869, 1894

ASC (Advanced Stellar Compass), 504, 555,558,588,599,880,1095,1099, 1105, 1121

ASCAT =Advanced Wind Scatterometer, 681

ASCE (Advanced Solar Cell Experiment), 1048

ASDL (NOAA Aircraft Satellite Data Link), 1753

ASPOC = Active SIC Potential Control, 886

ASSI = Airglow Solar Spectrometer Instrument, 233

AST20 (Autonomous Star Tracker 20), 1100

ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer), 17,378

ASTER simulator, 1666, 1667 ASTRAIA = Analyse Stereoscopique par

Radar Aeroporte sur Electra, 1635 ASTRE (Accelerometre Spatial Triaxial

Electrostatique ), 128 ASUR (Airborne Submillimeter SIS Ra

diometer), 1817 ASUSat Imager, 1141 ATHOS (Airborne Tropospheric Hydro

gen Oxide Sensor), 1566, 1918 ATLAS = Airborne Terrestrial Applica

tions Scanner, 1568 ATLAS = Airborne Tunable Laser Ab

sorption Spectrometer, 1567, 1850, 1895, 1907, 1913

ATLID = Atmospheric Lidar, 1255, 1621 ATM = Airborne Thematic Mapper, 1609 ATMOS = Atmospheric Trace Molecule

Spectrometer, 395, 821, 854


ATMOS = Atmospheric Trace Molecule Spectroscopy, 1296, 1298, 1727

Atmospheric Drag, 175

AIMS (Advanced Technology Microwave Sounder), 707

ATOMS (Atmospheric Tomography Experiment), 457

ATOS (Arcjet Thruster on OSCAR Satellite), 97, 1282

ATSR = Along Track Scanning Radiometer and Microwave Sounder, 403, 407, 1246, 1848, 1857, 1869, 1870, 1877, 1917

ATSS = Airborne Terrain Survey System, 1576

ATV = Visible and UV Auroral TV, 904

AutoNav (Autonomous navigation), 1021

AVCH-2T = HF-Field Analyzer, 877

AVCS (Advanced Vidicon Camera Sys-tem), 727, 728, 729, 730, 731, 737, 1077

AVHRR =Advanced Very-High Resolution Radiometer, 741

further consideration, 734, 735, 737, 1310

further mention, 383, 1676, 1847, 1848, 1851, 1853, 1855, 1857, 1860, 1864, 1869, 1870, 1874, 1877, 1879, 1881, 1882, 1888, 1890, 1891, 1892, 1894, 1896, 1901, 1904, 1906, 1910, 1917

AVHRR/3 = Advanced Very High Resolution Radiometer, 681, 748

AVIRIS =Airborne Visible/Infrared Imaging Spectrometer, 23, 1578, 1848, 1853, 1854, 1864, 1869, 1870, 1884, 1894, 1901, 1902

AVNIR = Advanced Visible and Near-Infrared Radiometer, 330, 342

AVNIR-2 (Advanced Visible and Near-In-frared Radiometer - 2, 342

AVS (Autonomous Vision System), 1121

AWl Sensors, 1581

AWiFS (Advanced Wide Field Sensor), 17,427

AWSR =Airborne Water Substance Radiometer, 1582

AXBT (Air Expendable Bathythermograph), 1755

AXIS (X-ray, proton and electron spectrometer), 261

8 B-Flux (Boundary-Layer Flux System),

1582, 1853, 1907

Balkan-1 = Lidar on MIR Station, 1000

BBHIR (Broad Bandpass Hemispheric Infrared Radiometer), 1779

BBHSR (Broad Bandpass Hemispheric Solar Radiometer), 1779

BCS =Bent-Crystal Spectrometer, 954

BCS = Bragg Crystal Spectrometer, 961 BEPT (Bradford Engineering Pressure

Transducer), 1120

BERIR (Broadband Earth Radiation Imaging Radiometer), 188

BGIS 2000 (Ball Global Imaging System 2000), 17, 278

BGSR (microGPS- Bit Grabber Space Receiver), 1173

BHRC 60 (Ball High Resolution Camera 60), 278

BIMS (Bennett Ion-Mass Spectrometer), 179

Blackbeard, 871 BlackJack (GPS Flight Receiver), 46, 139,

231,504,507,556,588,590,592,858, 1044

BLISS (Balloon-borne Laser In-Situ Sensor), 1534

BRE (Battery Recharge Experiment), 1112

BUV = Backscatter Ultraviolet Spectrometer, 47, 182, 737, 1081

c C/X-SAR = C-Band and X-Band SAR

(CCRS), 31, 1605, 1853, 1856, 1885, 1905, 1915

C-band Radar Transponder, 571, 572 C-P = Coronagraph - Polarimeter, 953 C-RADAR (C-band Radar Instrument),

30,861


C-SCAT (C-band Scatterometer), 1603, 1915

C-STAR (Conically-Scanning Two-Look Airborne Radiometer), 1604

CACTUS (Capteur Accelerometrique Capacitif Triaxial Ultra Sensible), 128

CAE (Charge Alleviation Experiment), 1112

CAESAR = CCD Airborne Experimental Scanner for Applications in Remote Sensing, 1585, 1885

CAl = Electron Isotopes Investigation, 925

CALS = Cloud and Aerosol Lidar System, 1586, 1847, 1848, 1850, 1856, 1870, 1886, 1901, 1902, 1917, 1919

Camera (Photographic Camera System), 1734

Camera Assembly, 1188

Cameras Photographic Systems

ESC -Electronic Still Camera (Shuttle), 854

Hasselblad 500 ELX (Shuttle), 855 Hasselblad 500-EL (MIR), 998 KAP-350 (Kvant 2 on MIR), 998 KATE-140 (Salyut), 1002 KFA-1000 (Resurs-F), 494 KFA-200 (Resurs-F), 493 LFC = Large Format Camera, 833 Linhof Aero Technika (Shuttle), 855 Metric Camera (Spacelab-1 ), 853 MK-4 (Resurs-F), 494 MKF-6 (Salyut), 1001, 1688 MKF-6MA (on Kvant 2 of MIR), 1000 Nikon F3, F4 (Shuttle), 855 Rolleiflex 6008 (Shuttle), 855 S190A (Skylab), 1002 S190B (Skylab), 1003 S191 (Skylab), 1003

TV Cameras Atlas (on Kvant 2 of MIR), 1000 EIS (PoSAT-1), 537 KL-103W (Color camera on Kvant2 of

MIR), 1000 MR-2000M (Meteor-3), 696 MR-900B (Meteor-3), 696 TV camera (Priroda), 482

CAMMICE = Charge and Mass Magnetospheric Ion Composition Experiment, 938

CAMPR = CRL Airborne Multi parameter Precipitation Radar, 1694

CAMS = Calibrated Airborne Multispectral Scanner, 1587

CAR = Cloud Absorption Radiometer, 1587, 1850, 1870, 1901

CARABAS = Coherent All RAdio BAnd Sensing, 31, 76, 1589, 1852

CARIBIC (Civil Aircraft for RemoteSensing and In-Situ-Measurements in Troposphere and Lower Stratosphere Based on the Instrumentation Container Concept), 1572

CASI = Compact Airborne Spectrographic Imager, 23, 1541, 1592

CASIMIR (Caltech Submillimeter Insterstellar Medium Investigations Receiver), 1805

CASIR (Clouds and Aerosol Shortwave Imaging Radiometer), 185

CASSAR = Chinese Academy of Sciences SAR, 31, 1598, 1908

Cast Eyes, 1594 CBE =Controlled Beam Experiment,

900 CBEMG (Confined Boiling Experiment

under Microgravity), 211 CCD Camera, 638 CCR (Carbon Carbon Radiator), 1030 CCS (CCD Camera System), 410 CDE (Compact Dosimeter Experiment),

347 CDL = Cloud Detection Lidar, 1626,

1764 CDMS (Cosmic Debris and Micrometeo

roid Sensor), 1117 CDS = Coronal Diagnostic Spectrometer,

956 CEASE (Compact Environmental Anom

aly Sensor Experiment), 1117, 1137 CEDEX (Cosmic Ray Energy Deposition

Experiment), 552 CEIS = CCD Earth Imaging System, 431,

536 CELIAS = Charge, Element and Isotope

Analysis, 958


CEP (Cylindrical Electrostatic Probe), 176

CEPAC = COSTEP/ERNE Particle Analyzer, 958

CERES (Clouds and the Earth's Radiant Energy System), 119, 257, 380, 1217, 1903

CERES = Clouds and the Earth's Radiant Energy System, 1309

CERTO (Coherent Radio Topography Experiment), 1013, 1094

CERTO/PLUS (Coherent EM Radio Tomography & Profiling the Limb with UV Sensors), 1119

CESS (Coarse Earth-Sun Sensor), 292, 556,561,587

CHADOCC (Circuit Hydraulique a Ammoniaque Diphasique en Orbite a Pompage Capillaire et Centrifuge), 211

CHASE =Coronal Helium Abundance Spacelab Experiment, 1297, 1407

CHAWS-LD (Charging Hazards and Wake Studies - Long Duration experiment), 1150

CHE = Cosmic Ray & Solar flare Isotopes Investigation, 925

CHEM = Charge-Energy-Mass Spectrometer, 875

Chemiluminescent Sensors FOZAN, 1554 NCARNOX, 1745 NO/NOy Instrument, 1673 OS-AP-M, 1573 UMMCI, 1824

CHIPS (Cosmic Hot Interstellar Plasma Spectrometer), 1144

CHOPPY = Chopped Pyrgeometer, 1599, 1843, 1857

CHRIS (Compact High Resolution Imaging Spectrometer), 1096

CHRISS = Compact High Resolution Imaging Spectrograph Sensor, 23, 1513, 1600

CID (Cold Ion Detector), 1113

ClOP (CLOUDS Integrated Optical Payload), 185

CIRIR (Clouds InfraRed Imaging Radiometer), 187

CIRRIS (Cryogenic Infrared Radiance Instrumentation for Shuttle), 824

CIS = Chinese Imaging Spectrometer, 23, 1596

CIS = Cluster Ion Spectrometer, 885

CIV (Critical Ionization Velocity), 1009

CIWSIR (Cloud Ice and Water-vapor Sub-mm Imaging Radiometer), 189

CLAES = Cryogenic Limb Array Etalon Spectrometer, 259

CLAPMIR (Cloud Liquid-water And Precipitation Microwave Imaging Radiometer), 190

ClO/BrO Instrument, 1671, 1763, 1850, 1895

ClON02 Instrument, 1673, 1763

CLS (Cloud Lidar System), 1586, 1856

CLS (Color Line Scanner), 1581

CLT (Cross Link Transceiver), 91

CMIS (Conical-scanning Microwave Imager/Sounder), 197, 716

CMOS Video Camera, 546

CNC = Condensation Nucleus Counter, 1601

C02 Instrument, 1673, 1763, 1913

CODIF = Composition and Distribution Functions analyzer, 885

COHU 5560 Low Light Camera, 1541

COIS (Coastal Ocean Imaging Spectrom-eter), 17, 21, 22, 25, 465, 1072

Collector Arrays, 911

Color Video Camera, 1192

Complex ASPI = Analysis of Plasma Spectra Instabilities, 929

COPAS = Condensation Particle Detec-tion System, 1555

COR1 (Coronagraph1 Imager), 967

COR2 (Coronagraph2 Imager), 967

CORALL = Wide-Range 3-D Ion Spectrometer, 929

COSPAS = Space System for the Search of Distressed Vessels, 811

COSPIN = Cosmic-ray and Solar Particle Investigation, 975


CPC (Condensation Particle Counter), 1574

CPE (Communications Payload/Experi-ment), 1043

CPE (Cosmic Particle Experiment), 534

CPE = Charged Particle Experiment, 599

CPI = Comprehensive Plasma Investiga-tion, 915

CPL (Capillary Pumped Loop), 210

CPLM (Column of Liquid Bridge in Microgravity), 1054

CPME = Charged Particle Measurement Experiment, 925

CPR (Cloud Profiling Radar), 193

CPV (Common Pressure Vessel type battery), 1047

CQCM (Cryogenically-cooled Quartz Crystal Microbalance), 1064

CRE = Cosmic Ray Experiment, 535, 538,553

CREDO (Cosmic Radiation Environment and Dosimetry Experiment), 534

CREDO-II (Cosmic Radiation Environment and Dosimetry Experiment), 1114

CRESPO (Coral Reef Ecosystem Spectro-Photometric Observatory), 986

CriS (Cross-Track Infrared Sounder), 710, 717

CRIS = Cosmic Ray Isotope Spectrometer, 864

CRISTA = Cryogenic Infrared Spectrometer and Telescopes for the Atmosphere, 816

CRL Radar/Radiometer, 1602

CRL-SAR (Communications Research Laboratory- SAR), 1766

CSD (Commercial Semiconductor Device), 1046

CSE (Cryo System Experiment), 61, 1238

CSS (Closed-Source Neutral Mass Spectrometer), 178

CTS (Chirp-Transform Spectrometer), 1817

CUBIC (Cosmic Unresolved X-Ray Background Instrument using CCDs), 942

CVI = Counterflow Virtual Impactor, 1555, 1605, 1843, 1888, 1914

CVSE (Cryocooler Vibration Suppression Experiment), 1114

CZCS = Coastal Zone Color Scanner, 383, 1086

further mention, 737, 1860

D D2P (Delay/Doppler Phase-monopulse

Radar), 562, 1608 DAIS-16115 (Digital Airborne Imaging

Spectrometer), 23, 1666, 1669 DAIS-2815 (Digital Airborne Imaging

Spectrometer), 23, 1667

DAIS-3715 (Digital Airborne Imaging Spectrometer), 23, 1670

DAIS-7915 (Digital Airborne Imaging Spectrometer), 23, 1668, 1892

DANI = Potential and Soft Particle Analyzer, 876

DAOCS (Drag, Attitude and Orbit Control System), 1067

DARMS (Digital Aerial Right-of-Way Monitoring System), 1620

DBI = Drag Balance Instrument, 233 DCIXS (Demonstration of a Compact

Imaging Xray Spectrometer), 1107 DCS (Data Collection System}, 1648,

1683 DCS =Data Collection System, 31, 311,

339,352,444,613,616,625,634,635, 736, 737, 754

DDM (Deep Dose Monitor), 1117 DEBIE (DEBris In-orbit Evaluator),

1099 Deimos, 1620, 1866, 1892

Delta-2D = Scanning Microwave Radi-ometer, 475

Delta-K Spectrometer, 1689

DEP-2E = Electric Field Instrument, 876 DEP-2R = AC Field Analyzer, 876

Device 174 K = IR Spectrometer, 469, 697

DGS = Directional Gamma-ray Spectrometer, 1177


DIARAD (Differential Absolute Radiometer), 119, 959

DIDM (Digital Ion Drift Meter), 559

DIFOS =Solar Flux Optical Photometer, 891,893

Digital Camera, 1165

DINA (Detector of Ions and Neutral Atoms), 1157

DIOGENESS = Diagnostic of Energy Sources and Sinks in Flares, 890, 893

DLTV = Day Light Television, 1542

DME = Soft Electron Detector, 867

DMSV (Digital Multi-Spectral Video), 1624

DO-SAR (Dornier SAR), 31, 1628

DOAS (Differential Optical Absorption Spectroscopy), 1518, 1624

DOAS-UV Czerny-Turner spectrograph, 1625

DOAS-VIS spectrograph, 1625

DOK-2A = Electron and Proton Experiment, 928

DOK-2X = Electron and Proton Experiment, 929

DOK-A-S =Silicon Detector Spectrometer, 869, 878

Doppler System GEOS-3, 572

DORIS = Doppler Orbitography and Radiopositioning Integrated by Satellite, One-Way Tracking System, 358,519, 523,592,603

DPA (Deflection Plate Analyzer), 1153

DPA = Digital Photogrammetric Assembly, 1629

DPL = Doppler Shift Measurement, 900

DRA-SAR (Defense Research Agency SAR), 31, 1631

DSPE (Digital Signal Processing Experiment), 552

DSPE = Digital Signal Processing Experi-ment,431,536,538,546

DIE = Data Transfer Experiment, 540

Dual Polarized 37 GHz Radiometer, 1632

Dual Vidicon Cameras, 1019

DUST = Dust Experiment, 976

DUTSCAT = DUT Airborne Radar Scatterometer, 1633

DWP = Digital Wave Processor, 885

E E-SAR (Experimental SAR), 31, 1653,

1866 E-SLAR (Experimental Side-Looking

Airborne Radar), 1654

EarthKAM (Earth Knowledge Acquired by Middle school students), 997

Earthwatch Imager, 456 EBM = EarlyBird Multispectra, 277

EBP = EarlyBird Panchromatic, 277

ECOC (Electrochemical Ozone Cell), 1552

ECP (Experimental Communication Payload), 500

ECSE (Encrypted CCSDS Space Experiment), 1119

EdEx = Educational Experiment, 540

EDI = Electron Drift Instrument, 885, 897

EDOP (ER-2 Doppler Radar), 1633, 1854, 1917

EFD = Electric Field Detector, 901, 915 EFF (Enhanced Formation Flying), 1032

EFI = Electric Field Experiment, 936

EFI = Electric Field Instrument, 234

EFLPI = Electric Field I Langmuir Probe Instrument, 948

EFW = Electric Fields and Waves, 883 EGG (Electrostatic Gravity Gradiome

ter), 129, 130, 579 '

EGNOS (European Geostationary Navigation Overlay Serv,ice ), 1017

EGS = Echelle Grating Spectrometer, 1541

EHIC = Energetic Heavy Ion Composition, 741

EIC (Earth Imaging Camera), 347, 1190

EICS = Energetic Ion Mass Spectrometer, 203

EIS (EUV Imaging Spectrometer), 963 EIS = Earth Imaging System, 535, 537,

540,546


EIT = Extreme UV Imaging Telescope, 957,967

EITA (Electron-bombardment Ion Thruster Assembly), 1016, 1288

ELDORA (ELectra DOppler Radar), 1635, 1917, 1919

ELECTRON= 3-D Electron Distribu-tion Function, 928

Electron Spectrometer (EXOS-A), 899

Electron Temperature and Density, 175

Electron Temperature Probe (Exos-C), 901

ELECTRON-5 (Charged Particle Spectrometer), 895

ELFWA =Extremely Low Frequency Wave Analyzer, 202

EMIL =Electron Measurements, In-situ and Lightweight, 879

EMIRAD = Electromagnetics Institute Radiometer, 1637, 1892

EMISAR = Electromagnetics Institute SAR, 31, 1638, 1866, 1891, 1892

EMITS (Electric Microthruster Test in Space), 1286

EMMA (Electrical and Magnetic field Monitoring of the Aurora), 881

ENAP (Energetic Neutral Atom Precipi-tation), 823

Energy Spectrum Analyzer (Exos-C), 901

EOC (Electro-Optical Camera), 17,437 EOS (Opto-Electronic Scanner), 18, 1639

EPAC = Energetic Particle Composition Experiment, 976

EPACT = Energetic Particles Acceleration, Composition, and Transport, 982

EPAM = Electron, Proton, and Alphaparticle Monitor, 864

EPAS = Electron and Proton Wide-Angle Spectrometer, 202

EPDM (Electric Propulsion Demonstrator Module), 96, 1289

EPDP (Electric Propulsion Diagnostic Package), 1107

EPE = Energetic Particle Experiment, 925

EPI=Energetic Particle Instrument, 897

EPIC (Earth Polychromatic Imaging Camera), 251

EPIC = Energetic Particle and Ion Composition Experiment, 915

EPIC= Energetic Particles and Ion Com-position Experiment, 202

EPS (Electric Propulsion System), 544 EPS = Energetic Particle Sensor, 620 EPV (Ensemble de Prise de Vues), 1427 ERASME = Etude Radar des Sols et des

Mers, 1641 ERB = Earth Radiation Budget, 737,

1084, 1087 ERBE = Earth Radiation Budget Experi

ment, 205, 737, 739, 743, 1676 ERIP (Earth Remote-Sensing Imaging

Package), 1183 ESA = Quadrispherical Electrostatic

Electron Analyzer, 947 ESC = Electronic Still Camera (Shuttle),

854 ESEX (Electric Propulsion Space Experi

ment), 96, 1009, 1289 ESMR (Electrically Scanning Microwave

Radiometer), 737, 1083, 1084, 1246, 1655, 1845, 1917

ESMR = Electronic Scanning Microwave Radiometer, 737

ESP = Charged Particle Detectors, 900 ESR (Enhanced Surveillance Radar),

1632 ESTAR = Electronically Steered Thinned

Array Radiometer, 1656, 1722, 1917, 1919

ESUM (Extreme Solar UV Monitor), 177 ETB (Electronics TestBed), 1120 ETB (Engineering Test Bed), 1137 ETM = Enhanced Thematic Mapper

(LS-6), 446 ETM + = Enhanced Thematic Mapper

Plus, 16,21,26,54, 91,158,448 ETP (Electron Temperature Probe), 434 ETRV (Experiencia Tecnol6gica de un

Regulador de Velocidad - Speed Regulator Technological Demonstrator), 1055

EURD (Espectr6grafo Ultravioleta extrema para Ia observaci6n de Ia Radia-


cion Difusa - Extreme UV Spectrograph for the Study of Diffuse Radiation), 1054

EUTEF (European Technology Exposure Facility), 987

EUV (Extreme Ultraviolet Imager), 922

EUV (Extreme Ultraviolet), 816

EUV-PHOKA (EUV Photocathode Ex-periment), 895

EUVI (Extreme Ultraviolet Imager), 967

EUVIP (Extreme Ultraviolet Imaging Photometer), 1007

EUVS (Solar EUV Spectrometer), 177

EXES (Echelon-Cross-Echelle Spectrograph), 1805

F F1: Electric Field Experiment (Freja), 905

F2: Magnetic Field Experiment (Freja ), 905

F3C: Particles Experiment - Cold Plasma, 906

F3H: Particles Experiment - Hot Plasma, 907

F4: Waves Experiment (Freja), 907

F5: Auroral Imager (Freja), 907

F6: Electron Beam Experiment (Freja), 908

F7: Particle Correlator Experiment (Freja), 908

FAST (Frequency-modulated Absorption Spectroscopy by Tunable diode lasers), 54, 1658, 1913, 1914

FAUST = Far Ultraviolet Space Tele-scope, 823

FCS = Flat-Crystal Spectrometer, 954

FDS = Photometer, 869

FEEP (Field Emission Electric Propul-sion), 1285

FFI (Fine Field Imager), 1800, 1801

FGM = Fluxgate Magnetometer, 883

FGMNHM = Fluxgate Magnetometer/ Vector Helium Magnetometer, 976

FGM-1 =3-D Magnetic Field, 930

FIFILS (Field-Imaging Far-Infrared Line Spectrometer), 1803

FIMS (FUV Imaging Spectrograph), 435

FIPEX (Flux Probe Experiment), 1121

FIRS-2 (Far Infrared Spectrometer), 53, 1658

FIRSC (Far Infrared Sensor for Cirrus), 40, 1660

FIS (Fuego Imager Suite), 806

FISH (Fast In-Situ Stratospheric Hygrometer), 1661, 1914

FLASH = FOA Laser Airborne Sounder for Hydrography, 1661

FLI = Fluorescence Line Imager, 23, 1592, 1662

FLIR (Forward Looking Infrared) camera, 1542

FLITECAM (First Light Infrared Test Ex-periment Camera), 1807

FluxRad (Fluxmeter Radiometer), 211

FM-3K (Fluxgate Magnetometer), 196

FOCUS (Fire Detection and Analysis Sensor System), 987

FODB (Fiber Optic Data Bus), 1031

FOG (Fiber-Optic Gyro), 134

FOLPEN = Foliage Penetration VHF Impulse SAR, 31, 1663

FORCAST (Faint Object infraRed CAm-era for the SOFIA Telescope), 1807

FOZAN = Fast Ozone Analyzer, 1554

FPI (Focal Plane Imager), 1800, 1801

FPI = Fabry-Perot Interferometer, 204

FPR = Flat Plate Radiometer, 737

Frecopa = French Cooperative Payload, 833

FRP (Flat Plate Radiometer), 728, 729, 730, 731

FSSP-100 (Forward Scattering Spectrometer Probe), 1769

FSSP-300 (Forward Scattering Spectrometer Probe), 1549

FTHSI = Fourier Transform HyperSpectral Imager, 22, 54, 1050

FTS = Fourier Transform Spectrometer, 40,43,48,52,53,1756

FTVHSI (Fourier Transform Visible Hyperspectral Imager), 23, 53, 1050, 1664


FUV (Far Ultraviolet Imager), 923

FUV (Far Ultraviolet), 816

FUVIS (Far UV Imaging Spectrograph), 845

FWS (Filter Wedge Spectrometer), 1082

FXM (Fast X-ray Monitor, MEPhl), 894

G GADACS (GPS Attitude Determination

and Control System), 786, 846

GADFLY (GPS Attitude Determination Flyer), 452, 455, 787

GAF = DC Electric Fields Investigation, 924

GAGE (GPS At GEO Experiment), 1117

GAS= Insterstellar Neutral Gas Experiment, 976

GASCOD =Gas Absorption Spectrometer Correlating Optical Differences, 1549

Gemma = Spectrometer System, 998

GEO/SAMS (Geostationary Synthetic Aperture Microwave Sounder), 42

GEOS&R (Geostationary Search and Rescue), 157,626,813

GER-63 = Airborne 63-channel Imaging Spectrometer, 1669

GER-63 Channel Scanner , 23, 1669 GERB (Geostationary Earth Radiation

Budget), 119, 651

GFSE (Gas Flow Sensor Experiment), 1118

GHIS (Geostationary HIS), 1676

GIFTS (Geosynchronous Imaging Fourier Transform Spectrometer), 10, 53, 1033

GIMI (Global Imaging Monitor of the Ionosphere), 1011

GISSMO (Gas Ionization Solar Spectral Monitor), 1175

GIT-12T (GLONASS/GPS Receiver System), 196

GLAS (Geoscience Laser Altimeter System), 412

GLI = Global Imager, 48, 337

GLRS = Geoscience Laser Ranging System, 412

GME =Solar and Cosmic Ray Particles Investigation, 925

GNF = Magnetic Fields Experiment, 924 GNS (GPS Navigation System), 242 GOES Imager = Visible and Infrared Ra-

diometer (NOAA), 622 GOES SOUNDER= Infrared Sounder

(NOAA), 623

GOLF = Global Oscillations at Low Frequencies, 959

GOLPE (GPS Occultation and Passive reflection Experiment), 140, 507

GOME = Global Ozone Monitoring Experiment, 407, 1817, 1861

GOME-2 (Global Ozone Monitoring Experiment-2), 685

GOMOS = Global Ozone Monitoring by Occultation of Stars, 47, 367

further considerations of GOMOS, 358

GPR = Ground Penetrating Radar, 1664 GPS Receiver, 1126

GPS receiver, 898

GPS Tensor, 786

GPS/MET = GPS Meteorology, 300, 556, 592, 784

GPSDR = GPS Demonstration Receiver, 603

GPSOS (GPS Occultation Sensor), 719 GRaBS (Gamma Ray Burst Spectrome

ter), 942 GRAS (GNSS Receicer for Atmospheric

Sounding), 46,153,166,681,686,688, 719, 754

GRB =Gamma-Ray Burst Experiment, 977

GREAT (German Receiver for Astronomy at Terahertz Frequencies), 1803

Greben = Precision Radar Altimeter (CIS), 1000

GRILLE = Infrared Spectrometer, 853

GRS = Gamma-Ray Spectrometer, 952, 953

GUVI = Global Ultraviolet Imager, 245 GWE = Gravitational Wave Experiment,

977


GXRE (Goddard X-Ray Experiment), 942

H H20 Instrument, 1671, 1913

H20-DIAL = Water Vapor Differential Absorption Lidar, 1622, 1857, 1858, 1864

HALOE = Halogen Occultation Experiment, 260, 1861

HAPI =High Altitude Plasma Instrument, 203

Hasselblad 500 ELX = Shuttle EO camera, 855

Hasselblad 500-EL = MIR camera, 998

HAWC (High-resolution Airborne Wide-bandwidth Camera), 1808

Hawk Eye, 1662

HB = Heat Budget Instrument, 737

HCMR =Heat Capacity Mapping Radi-ometer, 220

HELICON= Solar X-ray and Gammaray Scintillation Spectrometer, 890, 893

HELISCAT = Helicopter Scatterometer, 1673, 1900

HENA (High-Energy Neutral-Atom Imager), 922, 972

HEP = High Energy Particles Experiment, 915

HEPAD = High Energy Proton and Alpha Particle Detector, 620, 735, 737, 744

HEPD (High Energy Particle Detector), 438

HEPS (Charged particle spectrometer), 261

HEPT (High Energy Particle Telescope), 433

HESSI (High Energy Solar Spectroscopic Imager), 917

HET (High Energy Telescope), 970

HF Receiver, 1126

HI (Heliospheric Imager), 967

HI-SCALE= Heliosphere Instrument for Spectra Composition and Anisotropy at Low Energies, 977

HIA = Hot Ion Analyzer, 885 High-Volume Sampler with Normal Pres

sure Impactor, 1518 HILT = Heavy Ion Large Telescope, 946 HIP (Heterojunction Internal Photoemis

sion) Infrared Sensors, 1115 HIRAAS (High-Resolution Airglow/Au

rora Spectroscopy), 1009 HIRAASS = High Resolution Airborne

Autotracking Sun Spectrometer, 1764, 1819

HIRDLS (High-Resolution Dynamics Limb Sounder), 376, 391

HIROC (High Resolution Optical Camera), 1133

HIRS =High Resolution Infrared Radiation Sounder, 742

further consideration, 737, 1085 further mention, 383, 1676, 1846, 1864,

1905 HIRS/3 = High Resolution Infrared

Sounder, 681, 747 HIRS/4 (High Resolution Infrared Sound

er), 748 HIS (High-Resolution Interferometer

Sounder), 53, 1033, 1674, 1850, 1854, 1855, 1870

HITS (High Resolution Ionospheric/ Thermospheric Spectrograph), 1010

HONER (Hemispherical Optimized Netflux Radiometer), 1627, 1764

HOPI (High-speed Occultation Photometer and Imager), 1804

HPCE (High Performance Computer Experiment), 1045

HPCE = Hot Plasma Composition Experiment (CCE), 875

HPHET (High-Power Hall-Effect Thruster), 1290

HRC (High Resolution Camera), 1100 HRCC (High Resolution CCD Camera),

17,350 HRDI = High Resolution Doppler Imag

er, 261 HRG (High Resolution Geometric), 17,

526


HRI (High Resolution Imager), 433, 1179

HRIR (High-Resolution Infrared Radiometer), 737, 1077, 1078

HRMSI = High-Resolution Multispectral Stereo Imager, 449

HRS (High Resolution Stereoscopic), 17, 527

HRSC (High Resolution Stereo Camera, 1829

HRTC (High-Resolution Technological Camera), 505

HRTS = High Resolution Telescope and Spectrograph, 1297, 1428

HRV = High Resolution Visible (Sensor), 16,517,1310,1855,1869,1877,1890

HRVIR = High Resolution Visible and Infrared (sensor), 16, 521

HSB (Humidity Sounder for Brazil), 388 HSC (High Sensitivity Camera), 505

HSI (Hyper-Spectral Imager), 453 HSRS (Hot Spot Recognition Sensor),

801

HTSSE-11 (High Temperature Superconducting Space Experiment II), 63, 1006

HUTRAD (Helsinki University of Technology Radiometer), 1678, 1866

HUTSCAT =Helsinki University of Technology Scatterometer, 1680

HUTSLAR (HUT Side-Looking Airborne Radar), 1681

HXIS =Hard X-Ray Imaging Spectrometer, 954

HXR = Hard X-Ray spectrometer, 1177

HXRBS =Hard X-Ray Burst Spectrome-ter, 953

HXRS (Hard X-Ray Spectrometer), 462 HXRS (Hard X-Ray Spectrometer), 942

HXT = Hard X-Ray Telescope, 960

HYDICE = Hyperspectral Digital Imag-ery Collection Experiment, 24, 1683

HYDRA = Hot Plasma Analyzer Experiment, 937

HYPERBOLOID = Ion Mass Analyzer, 928

Hyperion, 1029

IALFS = Imaging Airborne Laser Fluorosensor System, 1701

lAP (Instrument Analyseur de Plasma), 1066

IASI =Improved Atmospheric Sounder Interferometer, 681, 684

I CARE (Influence of Space Radiation on Advanced Components), 507

ICE (Instrument Champ Electrique), 1066

ICI=Ion Composition Instrument, 898 IDICS (Image Dissector Camera System),

737, 1079, 1080 IDM =Ion Drift Meter, 204 IEF = Impedance and Electric Field

Measurement, 900 IES (Imaging Electron Sensor), 938 IESP-2 = Electric Field and Intensity Ex

periment, 927 IFPE = Investigations of Fluctuations of

Protons and Electrons, 929 IFSAR = Interferometric SAR, 31, 1686 IFSARE = Interferometric SAR for digi

tal terrain Elevation data, 31, 1650 IIR (Imaging Infrared Radiometer), 208 IKAR-D= MW radiometer, D=scanning

(CIS),478,486, 1000 IKAR-D2 = Passive Microwave Radiom

eter (Delta), 1774 IKAR-P = MW scanning Radiometer -

Panorama (CIS), 478, 486, 1000 IKAR-P =Passive Trace Microwave Ra-

. diameters RP-225 and RP600, 1774 IKAR=N =Apparatus of 5 Scanning Ra

diometers- Nadir (CIS), 479, 486, 1000 IKFS-2 (Infrared Fourier Spectrome

ter-2), 703 IKIRAD (IKI Radiometer), 1689 ILAS = Improved Limb Atmospheric

Spectrometer, 334 ILAS-11 = Improved Limb Atmospheric

Spectrometer-11, 338 Imaging Radars (active devices)

AMI (ERS-1,-2), 400, 407 ASAR (Envisat-1), 265, 272, 293, 296,

342,358,363,861


PR (TRMM), 255 RLSBO (Okean), 470, 473 SAR (Almaz-1), 346 SAR (Cosmos-1870), 344 SAR (JERS-1), 428 SAR (Radarsat), 488, 491 SAR (Seasat), 509 SAR (SIR-A), 848 SAR (SIR-B), 849 SAR (SIR-C, X-SAR), 850 SAR Travers (Priroda module on Mir),

479, 486, 1000

IMAPS (Insterstellar Medium Profile Spectrometer), 816

IMARC = Imaging Multifrequency Airborne Radar Complex, 31, 1822

IMG = Interferometric Monitor for Greenhouse Gases, 333

IMPACT (In-situ Measurements of Particles and CME Transients), 968

IMS (Ion Mass Spectrometer), 1063

IMS (Ionosphere Measurement Sensor), 438

IMS-HI = Ion Mass Spectrometer - High/ Medium Energy, 202

IMS-LO = Ion Mass Spectrometer- Low Energy, 202

IMSC (Instrument Magnetometre Search Coil), 1065

INES (Italian Navigation Experiment), 507

Infrared Radiometer, 944

INGARA =Australian Airborne Imaging Radar System, 31, 1690

IOE = Low Energy Particles Investigation, 924

IOF = AC Electric and Magnetic Fields Experiment, 924

ION = Ion Spectra Experiment, 927

Ion Mass Spectrometer (EXOS-A), 899

IONDS (Integrated Operational Nuclear Detection), 776

Ionospheric Plasma Probes (EXOS-A), 899

lOX (Ionospheric Occultation Experiment), 1094

IPD (Instrument Detecteur de Plasma), 1065

IPEI (Ionospheric Plasma and Electrodynamics Instrument), 500

IPEX-11 (Interferometry Program Experiment 2), 820

IPIP = IRM Plasma Instrument Package, 874

IPP (Ion Propulsion Package), 1016

IPS (Imaging Proton Sensor), 938

IPS (Instrument Pointing System), 1378

IPS (Ion Propulsion System), 69, 1021, 1284

IR = TV IR instrument, 695, 700

IR = TV IR instrument Lastocha, 693

IR Solar Spectrometer (EXOS-C), 901

IR!UV (Infrared/Ultraviolet System), 1611, 1733

IRCAM (Infrared Camera), 353

IREX (Infrared Experiment), 431

IRI = Infrared Imager, 1775

IRIS (International Retrieval of Information via Satellite), 314

IRIS = Infrared Interferometer Spectrometer, 80, 737, 1079, 1081

IRIS = Solar Burst Spectrometer, 891, 893

IRLS (Infrared Line Scanner), 1581

IRLS (Interrogation, Recording, and Location System), 737, 1079, 1082

IRMSS (Infrared Multispectral Scanner), 17,351

IRP = Infrared Passive, 737

IRR = Infrared (Imaging) Radiometer (part of ATSR), 403

IRR = Infrared Radiometer (Meteor, also known: by the name of SM), 700

IRT = Infrared Telescope, 1297

ISAAC (Ionospheric Spectroscopy & Atmospheric Chemistry spectrograph), 1011

ISAMS = Improved Stratospheric and Mesospheric Sounder, 260

ISEE-1 and -2 Sensms ANM/AND = Electrons & Protons In

strument, 931


BAM/PAD = Fast Plasma Experiment, 931

FRM/FRD = Low Energy Protons & Electrons, 931

GUM/GUD =Plasma Wave Investigation, 931

RUM/RUD = Fluxgate Magnetometer Experiment, 932

WIM!KED = Medium Energy Particles Experiment, 933

ISEE-1 Sensors HAM = Plasma Density Experiment,

932 HEM = VLF Wave Propagation Exper

iment, 932 HOM = Low Energy Cosmic Ray Ex

periment, 932 HPM = DC Electric Field Experiment,

932 MOM = Quasi-Static Electric Field Ex

periment, 932 OGM = Fast Electron Spectrometer

Experiment, 933 SHM = Ion Composition Experiment,

933

ISEE-2 Sensors, EGD =Solar Wind Ion Experiment, 932

ISEE-3 Sensors ANH = X-Rays and Electrons Instru

ment, 934 BAH = Solar Wind Plasma Experiment,

934 DFH = Low Energy Proton Experi

ment, 935 HKH = High Energy Cosmic Ray Ex

periment, 934 HOH = Low Energy Cosmic Ray Ex

periment, 935 MEH =Cosmic Ray Electrons and Nu

clei, 935 OGH =Plasma Composition Experi

ment, 935 SBH = Radio Mapping Experiment,

935 SCH = Plasma Wave Experiment, 935 SMH = Helium Vector Magnetometer,

935 STH = Heavy Isotope Spectrometer

Telescope, 935 TYH = Medium Energy Cosmic Ray

Experiment, 936

ISENA = Imaging Spectrometer for Energitic Neutral Atoms, 942

ISIR (Infrared Spectral Imaging Radiometer), 829

ISL (Instrument Sonde de Langmuir), 1066

ISM = Infrared Imaging Spectrometer, 1691

ISM = Infrared Spectro-Imager, 24 ISO = Imaging Spectrometric Observato

ry, 823 ISP-2 (lzmeritel Solnechnoy Postoyan

noy-2), 119, 497 ISSC (Improved Standard Spacecraft Cry

ocooler), 74, 1238 1ST (Italian Star Tracker), 506 ISTOK-1 = IR Spectroradiometric Sys

tem (CIS), 480, 1001 ISUAL (Imager of Sprite Upper Atmo

spheric Lightning), 124, 503 ITPR (Infrared Temperature Profile Ra

diometer), 1082 ITPR = Infrared Temperature Profile Ra

diometer, 737 ITS-7D = IR Telescope Spectrometer

(MIR), 1001 lVI = Ion Velocity Instrument, 234

J JAMI (Japanese Advanced Meteorologi

cal Imager), 115, 658 JMR (Jason Microwave Radiometer), 592

K K-band Dual-frequency Atmospheric Ra

diometer, 1689 KAP-350 = Space Camera for Remote

Sensing, 998, 1000 KaTE (X/Ka-band TT&C Experiment),

1107 KATE-140 = Camera System, 1002 KBR (K-Band Ranging), 589 KEM-1 = Magnetic and Electric Field

Analyzer, 868, 877 KFIKR (Krypton Flashlamp/Radiometer),

1064


KFA-1000 Camera System, 494, 998

KFA-200 Camera System, 493, 494

KGI-4S (Radiation Monitoring System), 704

KL-103 W = Klest (Crossbill name of a bird), MIR, 1000

Klimat = Infrared Radiometer, 697, 700

KM-10 = Cold Plasma Measurements, 876

KM-12 =Cold Plasma Analyzer, 868, 877

KM-6 ::;: Cold Plasma Analyzer, 867

KM-7 = Cold Plasma Experiment, 928

Kondor = DCPs data collector and trans-mitter, 471

KONUS =Gamma Ray Burst Investigation, 982

L LAC (LEISA Atmospheric Corrector),

1030

LAC = Large Area Collector, 1695

LAGRANGE (Laben GNSS Receiver for Advanced Navigation, Geodesy, and Experiments), 507

LANG = Langmuir Probe, 204

Langmuir Probe, 174, 724

LAP = Los Alamos Plasma Experiment, 924

LAPI = Low Altitude Plasma Instrument, 204

LARSEN = Airborne Scanning Lidar, 1696, 1882

LAS=Limb Scanning Spectrometer, 334, 901

LASAL (Large Aperture Scanning Airborne Lidar), 1696, 1882

LASCO =Large-Angle and Spectrometric Coronograph, 957, 967

LASE = Lidar Atmospheric Sensing Ex-periment, 1697, 1882, 1886, 1918

Laser Reflector Package, 603 Laser Tracking Reflector, 511, 569, 572

Lasercom (Laser Communication Experi-ment), 58, 1136

LASSII = Low-Altitude Satellite Studies of Ionosphere Irregularities, 201

LASSOR (Los Alamos Solid-State Optical Refrigerator), 1239

LAWS= Laser Atmospheric Wind Sounder, 43, 1255

LCDE (Laser Communications Demonstration Equipment), 989

LCE (Laser Communication Equipment), 58

LCE (Linear Concentrator Experiment), 1118

LDE (Lightning Dectection Experiment), 60

LEAF = Laser Environmental Airborne Fluorosensor, 1698

LEANDRE (Lidar Embarque Aerosols Nuages Dynamique Rayonnement Environment), 1699, 1865, 1867, 1896

LEE (Low-Energy Electron Experiment), 179

LEED (Low Energy Electron Detector), 431

LEGRI (Low Energy Gamma Ray Imager), 1055

Leica RC30 (Aerial Camera System), 1539, 1702, 1739

LEISA = Linear Etalon Imaging Spectrometer Array, 453

LENA (Low-Energy Neutral-Atom Imager), 920, 972

LEP = Low Energy Particle Detectors, 903

LEP = Low Energy Particles Experiment, 915

LET (Low Energy Telescope), 970

LFC = Large Format Camera, 833

LFR (Lower Fuselage Radar), 1751, 1860, 1912

LFS = Laser Fluorosensor, 1700, 1847

LFSA (Lightweight Flexible Solar Array), 1031

Lidar, 208

Lidar Systems (active laser systems) ABLE (U. of Rome), 1550 ALAS (NASNGSFC), 1531 ALEX (DLR), 1621


ALF (World Geoscience Corp., Perth, Australia), 1532

ALISSA (French sensor), 482, 486, 1000 ALPHA-1, -2 (SRI International), 1809 ALPS (NASNGSFC), 1535 ALTM (Optech Systems Corp.), 1536 AOL (NASNGSFC), 1544, 1915 Balkan-1 (Institute of Atmospheric Op-

tics, Tomsk), 1000 CALS (NASNGSFC), 1586 CDL (LLNL, Livermore, Ca.), 1626,

1847 FLASH (FOA, Sweden), 1661 H20-DIAL (DLR), 1622 Hawk Eye (Saab, FOA, Sweden), 1662 LARSEN (CCRS, Ottawa), 1696, 1793 LASAL (NASNGSFC), 1696 LASE (NASNLaRC), 1697 LEAF (CCRS, American Petroleum In-

stitute, US Coast Guard), 1698 LEANDRE (CNRS/CNES), 1699, 1882 LFS (University of Oldenburg), 1700 LITE (NASNLaRC), 834 M2M (SB-RAS), 1791 MACAWS, 1706 Makrel-2 (SB-RAS), 1789 Microlidar (DLR), 1623 NAILS (NCAR, Boulder Co.), 1738 NOAL (NOANERL/ETL ), 1755 OH/H02-Instrument (Harvard), 1671 OLEX (DLR), 1621 OLS (University of Oldenburg, Germa-

ny), 1760 RFUV (SRI International), 1811 SABL, NCAR, 1786 SHOALS (US Army Corps of Engin-

ners), 1792 Svetozar-3 (SB-RAS), 1790 TOPOSYS (Dornier), 1819 VIRL (NASNGSFC), 1827

LIMS = Limb Infrared Monitor of the Stratosphere, 1087

further mention, 737

LINDA (Langmuir Interferometer and Density experiment for Astrid-2), 881

Linhof Aero Technika = Shuttle EO film camera, 855

LIP = Lightning Instrument Package, 1703, 1854, 1855, 1917

LIS = Lighting Imaging Sensor, 257, 1703

LISS (I and II) = Linear Imaging SelfScanning Sensor, 16, 417, 418

LISS =Linear Imaging Self-Scanning Sensor, 16, 416

LISS-III = Linear Imaging Self-Scanning Sensor, 16, 419

LISS-III* (Linear Imaging Self-Scanning Sensor-III*), 427

LISS-IV (Linear Imaging Self-Scanning Sensor-IV), 17, 427

LITE (Lidar In-space Technology Experi-ment), 834, 1255, 1298

Lithium/Barium Experiments (IRM), 875

LLM (L-band Land Mobile), 1016

LMS (Lightning Mapper Sensor), 60, 628

LOI (Luminosity Oscillations Imager), 959

LORAAS (Low Resolution Airglow/Aurora Spectrograph), 670, 1010

Low-Resolution Omnidirectional Radi-ometer, 722, 723, 724

LPE (Langmuir Probe Experiment), 1113

LPI 80 (Low-Pressure Impactor), 1518

LRA (Laser Corner-cube Reflector As-sembly), 590

LRA (Laser Retroreflector Array), 593

LRIR (Long-Range Imaging Radar), 30

LRIR = Limb Radiance Infrared Radi-ometer, 737, 1085

LRR = Laser Retro Reflector, 358, 367, 403,558,580

LSAR (L-band SAR instrument), 30, 296

LSC (Line Scan Camera), 1581

LUCE (Laser Utilizing Communications Equipment), 58, 1091

M M-5 (Michigan-5 Imager), 1642

M-7 (Mapper Multispectral Testbed), 1643

M2M (Makrel-2 Modified), 1791

MACAWS (Multi-Center Airborne Coherent Atmospheric Wind Sensor), 1706


MACE (Middeck Active Control Experiment), 1378

MACEK (Mikroakcelerometr), 129, 597

MADRAS (Microwave Analysis & Detection of Rain & Atmospheric Structures), 222

MAE = Ion and Electron Investigation, 925

MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation), 236

MAG = Magnetic Field Monitor, 865

MAG-1 =Magnetometer on DE-l, 203

MAG-2 =Magnetometer on DE-2, 204

Magnetometer, 571

Magnetometer (CCE), 875

Magnetometer (IRM), 874

Magnetometer (UKS), 875

Magnetometer of SEM package, 620

Magnetometer Testbed, 1160

MAHRSI = Middle Atmospheric High Resolution Spectrograph Investigation, 818, 820

MAIS (Modular Airborne Imaging Spectrometer), 1597

MAKREL-2 Lidar, 1789

MAL (Micro-Joule Airborne Lidar), 1551

MAM (Magnetic Field Instrument), 897

MAMS = Multispectral Atmospheric Mapping Sensor, 1707, 1854, 1855

MAP =Multiple-Foil Micro-Abrasion Package, 833

MAP = Solar Plasma Faraday Cup Experiment, 925

MAPLE-1 (Microsystem and Packaging for Low Power Electronics), 1048

MAPS (Charged particle spectrometer), 261

MAPS (Measurement of Air Pollution from Satellites), 835, 853, 1298

MARA = Multimode Airborne Radar Altimeter, 1708, 1915, 1917

MARSS (Microwave Airborne Radiometer Scanning System), 1709, 1850, 1866, 1869, 1892

MAS (Multiwavelength Aerosol Scatterometer), 1548

MAS = Millimeter-Wave Atmospheric Sounder, 821, 1246, 1298, 1543

MAS = MODIS Airborne Simulator, 24, 1617, 1847, 1848, 1850, 1853, 1854, 1856, 1870, 1886, 1901, 1902, 1919

MASP = Multiangle Aerosol Spectrometer Probe, 1710, 1843, 1850, 1895, 1918

MAST = Mass Spectrometer Telescope, 946

MAVIR (Multi-Angle VIS Imaging Radiometer), 188

MAXIE = Magnetospheric Atmospheric X-Ray Imaging Experiment, 740

MBLA (Multi-Beam Laser Altimeter), 530

MCR = Multispectral Cloud Radiometer, 1713, 1850

MDC (Munich Dust Counter), 1142

MDIM (Meteoroid and Debris Impact Monitor), 1137

MEDUSA (Miniaturized Electrostatic Dual-tophat Spherical Analyzer), 881, 1157

MEIS (Metrological Earth Imaging System), 552

MEIS (Multispectral Earth Imaging System), 433, 551

MEIS = Multi-detector Electro-optical Imaging Sensor, 1714

MEMO= Analyzer of Magnetic Waves, 927

MENA (Medium-Energy Neutral-Atom Imager), 921, 972

MEOSS = Monocular Electro-Optical Scanner, 417

MEPA = Medium Energy Particle Analyzer (CCE), 875

MEPED = Medium Energy Proton and Electron Detector, 735, 737, 744, 752

MERES = Multifrequency Radiometer for Remote Sensing of the Sea Surface, 1715

MERIS = Medium Resolution Imaging Spectrometer, further consideration, 358, 1309


Merlion Communications Package, 544

MESA (Miniature Electrostatic Analyzer), 176

MESSR = Multispectral Electronic SelfScanning Radiometer, 459

Metric Camera, 853

MFCBS (Multi-Functional Composite Bus Structure), 1052

MFE = Magnetic Field Experiment, 936

MFI = Magnetic Field Investigation, 981

MFI = Magnetic Fields Instrument, 949, 1044

MGF = Magnetic Field Detector, 900, 902

MGF =Magnetic Field Experiment, 915

MHS = Microwave Humidity Sounder , 681,683,751

MIAS (Magnetometer Instrument Assembly System), 558

MICAS (Miniature Integrated Camera Spectrometer), 20, 1022

Microlidar, 1623

MicroMAPS (Micro-Measurement of Air Pollution from Satellites), 456

Micrometeorite Impact Detector, 1192

Microwave Radiometers (passive devices), overview on, 1246

AMSU =Advanced MSU, 747 ATSR = Along-Track Scanning Radi

ometer and MW Sounder, 403, 407 IKAR-D= Scanning MW Radiometer,

478, 1000 IKAR-N = MW Radiometers (5), 479,

1000 IKAR-P =Panorama Scanning MW Ra

diometer, 478, 1000 MAS = Millimeter-Wave Atmospheric

Sounder, 821 MLS = Microwave Limb Sounder, 392 MLS = MW Limb Sounder, 260 MSR = MW Scanning Radiometer, 459 MSU = Microwave Sounding Unit, 743 NEMS = Nimbus E MW Spectrometer,

737, 1083 R-400 = Polarization Scanner MW Ra

diometer, 479 RM-08 =Passive Microwave Radiome

ter, 470

SMMR = Scanning Multichannel MW Radiometer, 510, 1089

SMR = Submillimeterwave Radiometer, 223

SSM/I = Microwave Imager Radiometer, 665

TMI = TRMM MW Imager, 257 TMR = Topex MW Radiometer, 602

MIF-M = Multicomponent Investigations of Fluctuations of the Magnetic Field, 929

MIMR = Multi-frequency Imaging Microwave Radiometer, 1773

MIMR = Multifrequency Imaging Microwave Radiometer, 1679

MIMS (Magnetic Ion-Mass Spectrome-ter), 179

MINISCAT, 1682 Minitrack System, 570, 571 MIO =Miniature Imaging Optics, 880 MIPAS = Michelson Interferometer for

Passive Atmospheric Sounding, 358, 360, 1309, 1716

MIPAS-B (MIPAS Balloon), 53, 1717, 1863

MIPAS-B2, 53, 1718 MIPAS-FT (Flugzeug Transall), 53, 1518,

1625, 1719 MIPAS-LM (Laboratory Model), 1717 MIPAS-STR (MIPAS-STRATO), 53 MIR (Millimeter-Wave Imaging Radiom-

eter), 1720, 1854, 1917 MIRAC02LAS (Mid-IR Airborne C02

Laser Spectrometer), 1720 MIRAS (Microwave Imaging Radiometer

with Aperture Synthesis), 514, 1721 MIRIAM = MIR Infrared Atmospheric

Measurements, 483 MIROR = Michelson Interferometer

with Rotating Retroreflector, 53, 1723 MIS (Meteoroid Impact Sensor), 1180 MISI = Modular Imaging Spectrometer

Instrument, 24, 1725 MISR (Multi-angle Imaging SpectroRa

diometer), 381 MITE (Megapixel Imaging Technology

Camera System), 1726 MIVIS = Multispectral Infrared and Vis

ible Spectrometer, 24, 1616


MK-4 = Four-Channel Camera System, 494

MKF =Multispectral Camera, 1001, 1688

MKF-6 (Multi-Kanal-Fotografie-6), 13

MKF-6MA = Multispectral Space Cam-era (IKF), 1000

MkiV (Mark-IV Interferometer), 53, 1727

MKS-M = Multichannel Spectrometer, 998, 1001

MKS-M =Passive Multichannel Trace Radiometer, 1774

MLE (Mesoscale Lightning Experiment), 60

MLS = Microwave Limb Sounder, 260, 392, 1861

MMRS =Multispectral Medium Resolution Scanner, 505

MMS = Meteorological Measurement System, 1728, 1850, 1907, 1913

MMW-SAR (Millimeter Wave SAR), 31, 1729

MNCH = Search-Coil Magnetometer, 877

MOBY =Marine Optical Buoy, 1731

Mode-A Transponder, 1167

Mode-L Transponder, 1167

Model 1000 camera system, 287

MODIS (Moderate-Resolution Imaging Spectroradiometer), 377, 383, 386

MOMS =Modular Optoelectronic Multispectral Scanner, 836

further consideration, 837

MOMS-2P (Modular Optoelectronic Multispectral/Stereo Scanner - 2 Priroda), 483

MOMSNAV (MOMS Navigation), 485

MONITOR-3 =Solar Wind Analyzer, 929

MOPITT (Measurement of Pollution in the Troposphere), 385

MOS = Multispectral Optoelectronic Scanner, 421, 481

MOS-Obsor-A = Modular Optoelectronic Scanner, 1000

MOS-P (Modular Optoelectronic Scanner - Priroda), 481

MOZAIC (Measurement of Ozone by Airbus In-Service Aircraft), 1570

MP-900M TV Camera, 498

MPID (Micro-Particle Impact Detector), 1049

MPIR = Multispectral Pushbroom Imaging Radiometer, 1625, 1764

further mention, 1625, 1847

MPS (Micro-Propulsion System), 549

MPS SEA= Energetic Particle Spectrometer, 869, 878

MR-2000 = TV Camera System, 696, 700

MR-900B = TV Camera System (CIS), 696, 700

MRIR = Medium Resolution Infrared Radiometer, 737, 1078

MRSE = Microwave Remote Sensing Experiment, 853

MSC (Multi-Spectral Camera), 17, 439 MSEIS (Multi-Spectral Earth Imaging

System), 552 MSGI-MKA (Spectrometer for Geoactive

Measurements), 703 MSI (Multispectral Imager), 543

MSIS = Mass-Separating Ion Spectrometer (IRM), 874

MSMR (Multifrequency Scanning Microwave Radiometer), 425

MSR = Microwave Scanning Radiometer, 459, 1246

MSRS (Multi-Spectral high Resolution System), 17,267

MSS = Maritime Surveillance System, 1732

MSS =Multispectral Scanner System, 16, 443, 1310

MSS Fragment (Multispectral Scanning System Fragment), 11, 16, 694, 695

MSSCC (Multicolor Spin scan Cloud Camera), 114, 737

MSU = Microwave Sounding Unit, 743, 1309

further consideration, 737, 1246 MSU-E =Multispectral Scanner- Elec

tronic Scanning (CIS), 16, 18, 480, 486,496,694,1000


MSU-M =Multispectral Scanner, 1774

MSU-M =Multispectral Scanner- Low Resolution (CIS), 469, 471, 473, 695

MSU-MR (Low Resolution Multispectral Scanner), 703

MSU-S =Multispectral Scanner- Moderate Resolution (CIS), 471, 694

MSU-SK = Multispectral Scanner- Moderate Resolution and Conical Scanning (CIS), 16, 473, 480, 486, 496, 694, 1000

MSU-SR (Medium Resolution Multispectral Scanner), 703

MSU-V =High-Resolution Multispectral Scanner, 473

MTB (Microwave Test Bed), 1118

MTI (Multispectral Thermal Imager), 461

MTP = Microwave Temperature Profiler, 1735, 1763, 1850, 1907, 1913, 1918

MTS (Microwave Temperature Sounder), 1744

MTS (Millimeter-Wave Temperature Sounder), 1736, 1854, 1855, 1917

MTS-AMOS (Micro Tech Sensor-Attitude and Orbit Measurement System), 1057

MTVZA (Microwave Radiometer for Temperature Sounding of the Atmosphere), 702

Multipolarization K- and Ka-band Polarimeters, 1690

MUSE (Monitor of UV Solar Energy), 737, 1080, 1081

MUSIC (Multi-Spectral Infrared Camera), 24, 1737

MUXCAM (Multispectral Camera), 353

MVE (Micro-Vibration Measurement Equipment), 75, 1092

MVISR (Multichannel Visible and IR Scanning Radiometer), 689, 691

MVS (Machine Vision System), 145, 548

MWIR (Medium Wave Infrared Imager), 1135

MWR (Scanning Microwave Radiometer), 1732, 1733

MWR =Microwave Radiometer, 358, 370

MWR = Microwave Radiometer (part of ATSR), 403, 1246

N NACE (Neutral Atmosphere Composi

tion Experiment), 182 NACS = Neutral Atmosphere Composi

tion Spectrometer, 204 NAILS= NCAR Airborne Infrared Lidar

System, 1738 NAM-5 = Radiofrequency Mass

Spectrometer, 867, 877 NAMR (Nadir-looking Airborne Multi

channel Radiometer), 1688, 1880 NAPP (National Aerial Photography Pro

gram), 1739 NASAR-1 (NASDA Airborne SAR-1), 31,

1740 NASIC (NASA Aircraft - Satellite Instru

ment Calibrator), 1740 NAST (NPOESS Aircraft Sounder

Testbed), 1033, 1742 NAST-I (NPOESS Aircraft Sounder

Testbed - Interferometer), 1743 NAST-M (NPOESS Aircraft Sounder

Testbed - Microwave Sounder), 1744 NATALYA-2M (Gamma-ray Spectrome

ter, FIRAS and MEPhi), 894 NATE (Neutral Atmosphere Temperature

Experiment), 178 NCARNOX (NCAR NOx Chemilumines

cent Sensor), 1745, 1824 NCLT (Nanosatellite Cross Link Trans

ceiver), 91 NEC-SAR (NEC Corporation SAR), 31,

1747 NEMS = Nimbus E Microwave

Spectrometer, 737, 1246 NEOPONA (Nitrogen Oxide Emission

and Photochemistry over the North Atlantic), 1571

Neutral Mass Spectrometer, 174 Neutral Particle Magnetic Mass

Spectrometer, 175 NewMag (Magnetometer Experiment),

1044 NFOVR (Narrow FOV Radiometer),

1779


Nikon F3/F4 = Shuttle EO film camera, 855

NINA (New Instrument for Nuclear Analysis), 498

NINA-2 (New Instrument for Nuclear Analysis), 1056

NISTAR (National Institute of Standards and Technolohy Advanced Radiometer), 120, 252

NIT (Side-looking Airborne Real Aperture Radar), 1688, 1880

NMS (Neutral Mass Spectrometer), 1063

NNE (Neural Networks Experiment), 1115

NO/NOy Instrument, 1673

NOAA P-3 Infrared Radiometers, 1754

NOAA WP-3D Doppler Radar System, 1750, 1855, 1866

NOAL = NOAA Ozone Airborne Lidar, 1755, 1859, 1913

NOSL (Night-time and daytime Optical Survey of Lightning), 60

NPW-A =Natural Plasma Wave Astronomy Mode, 899

NS001 = Thematic Mapper Simulator, 1758, 1877, 1884, 1890, 1894

NSCAT = NASA Scatterometer, 331, 1706, 1903

NSCAT II = NASA Scatterometer II, 227,338

NSX (NRL SGLS Transponder), 1052

NTR (Nose-mounted Doppler Turbulence-detection Radar), 1750

NUSCAT (Airborne Ku-band Scatterometer), 1758, 1915

NVK-ONCH (Low Frequency Wave Analyzer), 196

NVK-ONCH = VLF Analyzer, 866, 876

NVK-ONCH = VLF Electromagnetic Waves Experiment, 927

0 03 Instrument, 1672, 1763, 1913

OAP-230X = Optical Array Cloud Droplet Probe, 1769

OCE = Ocean Color Experiment, 849

OCI (Ocean Color Imager), 500

OCM (Ocean Color Monitor), 424

OCS (Ocean Color Scanner), 410

OCS = Ocean Color Scanner, 849

OCSE (Optical Calibration Sphere Ex-periment), 1153

OCTS = Ocean Color and Temperature Scanner, 330

ODD (Orbiting Debris Device), 1122

ODUS (Ozone Dynamics Ultraviolet Spectrometer), 48, 216

ODW (Omega Dropwind Sonde), 1754

OH/H02 Instrument, 1671, 1763, 1850, 1907

OHIS (Orb View Hyperspectral Imaging System), 17,307

**Empty**, 17,274

OHRIS (Orb View High Resolution Imaging System), 17,305,307

OLEX = Ozone-Aerosol Lidar Experiment, 1518, 1621, 1622, 1625

OLME = Ozone Layer Monitoring Experiment, 47, 540

OLS (Optical Lightning Subsystem), 60, 214

OLS = Oceanographic Lidar System, 1760

OLS = Operational Linescan System (DMSP), 663, 1855, 1888, 1910, 1917

OM-2 (Ozone Meter-2), 1182 OMI (Ozone Monitoring Instrument),

393 OMPS (Ozone Mapping and Profiler

Suite), 718 OPALE (Optical Payload for Intersatel

lite Link Experiment), 58, 523, 1016

OPERA = Onde di Plasma Et Radiazioni Aurorali, 929

OPPEX (Optical Precision Platform Ex-periment), 1095

OPS = Optical Sensor, 429 Optical Beacon System, 569, 570

ORA = Occultation Radiometer Instrument, 827

0rsted-2 (Magnetic Mapping Payload), 506


OS-AP-M (Ozone Sonde Aircraft Platform Mid-altitude), 1573

OSA (Optical Sensor Assembly), 17, 286

OSIRIS = Optical Spectrograph and Infrared Imaging System, 225

OSMI (Ocean Scanning Multispectral Imager), 437

OSS (Open-Source Neutral Mass Spectrometer), 178

OTD = Optical Transient Detector, 299

OVID (Optical Visible and Near-Infrared Detector), 1760, 1857, 1867

OXFLUX (Oxygen Flux), 1142

Ozon-M = Multichannel UV Spectrometer on MIR, 482, 999

Ozone Analyzer, 1571

p

P-3/SAR (ERIM/Navy Sensor), 31, 1646, 1856, 1880, 1900, 1908

P3 = Pulsed Plasma Probe, 202

PALlS (Polarized Airborne Laser Imaging Sensor), 1536

PALSAR (Phased Array L-band Synthetic Aperture Radar), 30, 342

PAN= Panchromatic Camera, 16, 419

PAN-A (Panchromatic Aft-pointing Camera), 17,426

PAN-F (Panchromatic Forward-pointing Camera), 17,426

PANCAM (Panchromatic Camera), 353

PARCS (Primary Atomic Reference Clock in Space), 990

PASM (Power Actuation and Switching Module), 1024

PASS (Payload Autonomous Star Sensor), 1099

PASTEL (PAssager SPOT de Tecommunication Laser), 58, 523, 1015

PBEX (Polymer Battery Experiment), 1094

PBMR = Pushbroom Microwave Radiometer, 1761, 1869, 1877, 1890

PCASP-100X =Passive Cavity Aerosol Spectrometer Probe, 1768

PCD (Potential Control Device), 898

PCS (Parallel Computer System), 1047

PDP (Plasma Diagnostic Package), 210

PDP= Plasma Diagnostics Package, 1297, 1455

PEACE = Plasma Electron and Current Analyzer, 885

PEAS = Electron and Ion Analyzer, 876

PEM = Particle Environment Monitor, 261

PENGUIN (Hard X-ray Polarimeter and Neutron Detector, IFTI and MEPhi), 894

PEPE (Plasma Experiment for Planetary Exploration), 1023

PES (Photoelectron Spectrometer), 177

PEST (Plasma Experiment Satellite Test), 1153

PET (Photovoltatic Engineering Testbed), 990

PET = Proton/Electron Telescope, 946

PGAMS (Portable Ground-based Atmospheric Monitoring System), 1167

PHARAO (Project d'Horloge Atomique a Refroidissement d' Atomes en Orbite ), 986

PHARS - Testbed/Prototype Phase of PHARUS, 1765

PHARUS =PHased ARray Universal SAR, 31, 1764

Photometer, 1148 PI-SAR (Polarimetric and Interferometric

- SAR), 1766 PIC (Panchromatic Imaging Camera), 17,

283,467,1074

PIC-2 (Panchromatic Imaging Camera-2), 17,284

Picosat Launcher and Payload, 1160 PicoSat-1.1 Experiment, 1052 PIP (Plasma In-situ Package), 435

PIPPI = Prelude in Planetary Particle Imaging, 879

PIXIE= Polar Ionospheric X-ray Imaging Experiment, 940

PLASMA = 3-D Plasma and Energetic Particles Experiment, 982

Plasma Wave Spectrometer (CCE), 875


Plasma Wave Spectrometer (UKS), 875

PlasMag (Plasma Magnetometer), 253

PLASTIC (PLAsma and Supra Thermal Ion and Composition), 970

PLP (Planar Langmuir Probe), 559

PM (Proton Monitor), 1118

PM06-V (Physikalisch-Meteorologisches Observatorium, 6th radiometer - VIRGO), 959

PMR (Pressure Modulated Radiometer), 1085

PMR = Pressure Modulated Radiometer, 737

PMS = Portable Multichannel Spectrometer, 1769

PMS LAS-X (Laser Aerosol Spectrometer with Passive Cavity), 1518

PMS LPC 550 (Laser Particle Counter), 1518

POAM-II = Polar Ozone and Aerosol Measurement), 47, 519

POAM-III (Polar Ozone and Aerosol Measurement), 47, 524

POLAS-128 (Polarization-sensitive Acousto-optic Spectrometer), 474

POLDER = Airborne Instrument, 1771, 1850, 1867, 1877, 1884

POLDER =Polarization and Directionality of the Earth's Reflectances, 332, 339, 1069

POLRAD =Polish Radiometer, 927

PORTOS, 1773, 1877

Poseidon-2 (Solid-State Radar Altimeter), 591

PPC (Pointed Proportional Counter), 422

PPS-1350 (Propulseur Plasmique Stationaire- or Stationary Plasma Thruster-1350), 1106

PPT (Pulsed Plasma Thruster), 1031

PR = Precipitation Radar, 255, 1564, 1633, 1903

PR41/53 (UHF Receivers), 196

PRAM = Adaptive Processing of Wave Information, 930

PRARE = Precise Range and Range Rate Equipment, 403

further considerations, 405, 407, 699, 700

Precipitating Electron Detector, 571

PREMOS (Precision Monitoring of Solar variability), 120, 1071

Pressure Gauge, 174, 175

Priroda-5 = KFA-1000 Camera System, 998, 1000

PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping), 17, 341

PROMICS-3 = Ion Composition Experiment, 927

PROMICS-3 =3-D Ion Composition Spectrometer, 928

PRS = Plasma Wave Spectrometer, 867

PRS-2-C = Radiowave Spectrometer, 869,878

PSA (Pressure Sensor A), 181

PSB (Pressure Sensor B), 181

PVP = Generator of Electric Oscillations, 866

PWI = Plasma Wave Instrument, 203, 936

PWI = Plasma Wave Instrumentation (IRM), 874

PWI = Plasma Waves Investigation, 915

PWS = Plasma Wave Detectors and Sounder, 903

a QC40 (Quad-TMS320C40 processor),

1052 QIMS = Quadrupole Ion Mass

Spectrometer, 202

QOMAC (Quarter-Orbit Magnetic Attitude Control), 726

QWIP (Quantum Well Infrared Photodetector ), 1119

R R-400 = MW Radiometer (CIS), 479, 486

R-225 = Passive Microwave Radiometer, 476


R-600 = Passive Microwave Radiometer, 476

R-SLAR (RRL-SLAR), 1786

R-TARAC (Real-Time Airborne Radionuclide Analyzer and Collector), 1543

RlOM = Radiation Measurement Com-plex, 695

RA = Radar Altimeter, 574

RA-1 =Radar Altimeter, 402, 1892

RA-2 = Radar Altimeter-2 (ESA), 366

RACE (Rubidium Atomic Clock Experi-ment), 991

RACS (Rotating Antenna C-band Scatterometer), 1777, 1897

Radar Altimeter, 407, 510, 571, 573

Radar Altimeter (active devices) ALT (Topex/Poseidon), 602 Altimeter (Seasat), 510 GEOS-3, 571 GEOSAT,573 GF0-1, 574 RA-1 (ERS-1,-2), 402,407 RA-2 (Envisat), 366 RA-2 (POEM), 358 SSALT (Topex/Poseidon), 603

Radar Scatterometer AMI-SCATT (ERS-1,-2), 401,407 NSCAT (ADEOS), 331 SASS (Seasat), 511 Sea Winds (NASA/JPL), 227, 338

Radio Doppler System, 569, 570

Radio Range/Rate System, 570

Radius = Microwave Radiometer, 1778

RAL-Sensor, 1817

RAMS = RAdiation Measurement System, 1779, 1847, 1850, 1856, 1870, 1901, 1902, 1917

RAMSES = Radar Aeroporte MultiSpectral d'Etude des Signatures, 31, 1780

RAPID =Research with Adaptive Particle Imaging Detectors, 886

RBV =Return Beam Vidicon, 16,443

RDRS (Radiation Dose Rate Sensor), 1114

RedEye (Regional Environmental Dynamics Active-aperture Infrared Imager), 55

REFLEX (Return Flux Experiment), 845 REIS (Complex for the Measurement of

Electromagnetic Fields), 895 REIS (RapidEye Earth Imaging System),

17,309 REM (Radiation Environment Monitor),

1115 REME (Radiation Effect on Micro-Elec

tronics), 433 RENE, 1781 RES-C =Solar X-Ray Spectral Polarime

ter, 890, 893 RESSAC (Radar pour l'Etude du Spectre

des Surfaces par Analyse Circulaire ), 1782, 1915

REX (Radiation Experiment), 228 RF (Radio Frequency) System, 214 RF Ion Mass Spectrometer, 175 RF-15 = Solar X-Ray Experiment, 929 RFA (High Frequency Wave Analyzer),

196 RFUV (Raman, Fluorescent and UV-

DIAL Lidar), 1811 RGA3 (Reduction Gas Analyzer), 1573 RGR (Relative GPS Receiver), 91 RIMS = Retarding Ion Mass Spectrome

ter, 203 RIS = Retroreflector in Space, 334 RIT-10 (Radio-frequency Ionization

Thruster), 1286 RITA (Radio-Frequency Ion Thruster As

sembly), 580, 827 RITA (Radio-frequency Ion Thruster As

sembly), 1016, 1286 RLG (Ring Laser Gyro), 133 RLSBO =Side-Looking Real Aperture

Radar, 470, 473 RM -08 = Passive Microwave Scanning

Radiometer, 470 RMK = ReihenmeBkammer - Metric

Camera, 1783, 1865, 1880 RMK A = ReihenmeBkammer (Metric

Camera), 1784 RMK-2 = Radiation Measurement Com

plex, 498, 695, 697, 700


RMK-M (Radiation Measurement Control), 498

RMS (Radiation Measurement System), 608,632

RMT (Radiofrequency with Magnetic field ion Thruster), 1285

Rolleiflex 6008 = Shuttle EO film camera, 855

RON = Ion Emitter Experiment, 928

ROSIS = Reflective Optics System Imaging Spectrometer, 24, 1774, 1784

ROWS = Radar Ocean Wave Spectrometer, 1785, 1915

RPA (Retarding Potential Analyzer/Drift Meter), 177

RPA =Retarding Potential Analyzer, 204

RPI (Radio Plasma Imaging), 923

RPM-0.8 WA (Radiometer/Polarimeter/ Multipolarization, 0.8 em wavelength, Waveguide, Airborne), 1690

RPM-1.5 WA (Radiometer/Polarimeter/ Multipolarization, 1.5 em wavelength, Waveguide, Airborne), 1690

RRA (Retro-Reflector Array), 532

RRA (RetroReflector Array), 693

RSI (Remote Sensing Instrument), 17, 503

RSIS (Radio Science Investigation Series), 1107

RT-2 (X-ray Telescope), 894

RTVK-M (Radio and TV Complex), 473

s S 192 = Multispectral Opto-mechanical

Scanner, 1003

S 300 = Search Coil Magnetometer, 567

S 302 = Electrostatic Analyzers, 568

S 303 = Combined Electrostatic and Magnetic Analyzer, 568

S 310 = Electrostatic Analyzers, 568

S 321 = Magnetic Deflection System, 568

S 329 = Tracing of Electron Beam over one or more Gyrations, 568

S 331 = Fluxgate Magnetometer, 568

S&FE (Store & Forward Experiment), 347

S&R =Search & Rescue, 737

S&R =Search and Rescue (System), 626, 681, 738, 747

S&RSAT (Search&Rescue Satellite Aided Tracking System), 688

S&RSAT=Search and Rescue Satellite Payload, 811

S-VISSR (Stretched - Visible and Infrared Spin-Scan Radiometer), 610

S-193 =Passive Microwave Radiometer/ Active Scatterometer and Radar Altimeter, 12, 572, 1003

S-194 = Passive Microwave Radiometer, 1004

S190A = Multispectral Photographic Camera (Sky lab), 1002

S190B =Earth Terrain Camera (Skylab), 1003

S191 =Infrared Spectrometer (Skylab), 1003

S193 =Passive MW Radiometer/Active Scatterometer (Skylab ), 1246

S194 =Passive Microwave Radiometer (Skylab ), 1246

SABER = Sounding of the Atmosphere using Broadband Emission Radiometry, 244

SABL = Scanning Aerosol Backscatter Lidar, 1786

SAFI (Solar Array Flexible Interconnect), 1052

SAFIRE (Submillimeter And Far InfraRed Experiment), 1806

SAFIRE-A (Spectroscopy of the Atmosphere w. FIR Emission- Airborne), 53, 1547

SAGE III (Stratospheric Aerosol and Gas Experiment III), 704

SAGE-I = Stratospheric Aerosol and Gas Experiment, 183

SAGE-II =Stratospheric Aerosol and Gas Experiment II, 207

SAl = Spin-Scan Auroral Imager, 204

SAM II = Stratospheric Aerosol Measurement II, 1088


SAMIR (Satellite Microwave Radiometer), 349, 1246

SAMMES (Space Active Modular Materials Experiment System), 1136

SAMS = Stratospheric and Mesospheric Sounder, 260, 1088


Sandia SAR, 31, 1540

SAPHIR (Sondeur Atmospherique du Profil d'Humidite Intertropicale par Radiometrie ), 222

SAR = Synthetic Aperture Radar, 30, 344,346,848

further considerations, 30, 400, 428, 479, 488,491,509,849,850

SAR Travers = Synthetic Aperture Radar, 31, 1773

SAR-10 (Synthetic Aperture Radar-10), 30,265

SAR-2000 (Synthetic Aperture Radar-2000), 30, 272

SAS (Satellite Attitude Sensor), 1119

SAS&R = Satellite Aided Search and Rescue (Indian system), 635

SASAR =South African SAR, 31, 1787

SASS = Seasat-A Scatterometer System), 511

SBUV = Solar Backscatter Ultraviolet, 47,822,861,1089,1298


SBUV/3 = Solar Backscatter Ultraviolet Radiometer, 743, 752

SBV (Space Based Visible) camera, 1063

SCA (Star Camera Assembly), 589

Scalar Magnetometer, 599

Scalar Magnetometer (Magsat), 595

ScaLARS (Scanning Laser Altitude and Reflectance Sensor), 1576

SCAMS (Scanning Microwave Spectrometer), 1085

SCAMS = Scanning Microwave Spectrometer (NOAA), 737, 1246

Scanning Radiometer, 722, 723, 724

ScaRaB (Scanner for Radiation Budget), 119,221,498,698,700

SCARLET-II (Solar Concentrator Array with Refractive Linear Element Technology), 1024

SCDE (Surface Charge Detector Experiment), 1113

SCE = Solar Corona Experiment, 978 SCIAMACHY = Scanning Imaging Ab

sorption Spectrometer for Atmospheric Cartography, 372, 1309

further considerations of, 358 SCL (Spacecraft Command Language),

1120 SCMR (Surface Composition Mapping

Radiometer), 737, 1083 SCPS (Space Communications Protocol

Standards), 1120 SCR (Cosmic Ray Spectrometer), 893 SCR (Selective Chopper Radiometer),

1082, 1083 SCR (Surface Contour Radar), 1709 SCR = Selective Chopper Radiometer,

737 SCTE (Solar Cell Technology Experi

ment), 1115, 1118 SCTE = Solar Cell Technology Experi

ment, 535 SDST (Small Deep Space Transponder),

1023 SEASIS (SEDSAT Earth Atmospheric

and Space Imaging System), 1166 SeaWifs =Sea-viewing Wide-Field Sen

sor, 302 Sea Winds = NASA Scatterometer (old

name NSCAT II), 227, 338 SECOR (Sequential Collation of Range),

569,570 SEDA (Space Environment Data Acquisi

tion), 1046 SEDA-AP (Space Environment Data Ac

quisition equipment-Attached Payload), 991

SEE (Space Environmental Effects), 1115 SEE = Solar EUV Experiment, 244 SELODE (Solar Exposure to Laser Ord-

nance Device), 846 SEM = Space Environment Monitor, 352,

613,619,681,688,737,744 SEM-2 (Space Environment Monitor-2),

752


SEP (Solar Energetic Particles), 969

SEP = Spectrometer for Electron and Protons, 202

SEPAC = Space Experiments with Particle Accelerators, 823

SEPICA = Solar Energetic Particle Ionic Charge Analyzer, 864

SEPT (Solar Electron Proton Telescope), 969

SESAM (Surface Effects Sample Monitor), 816, 819

SESS (Space Environment Sensor Suite), 719

SETS (Shuttle Electrodynamic Tether System), 1132

SEU (Single Event Upset), 433

SEU (Single Event Upset)/RADMON (Radiation Monitor) Experiment, 1115

SEVIRI (Spinning Enhanced Visible and Infrared Imager), 649

SFSI = SWIR Full Spectrographic Imag-er, 24, 1791, 1792

SGR (Space GPS Receiver), 544

SGR-05 (Space GPS Receiver-05), 550

SGR-5 = Fluxgate Magnetometer, 877

SGR-7 = 3-axis Fluxgate Magnetometer, 867,877

SGR6 = 1-component Fluxgate Variometer, 867, 877

SHASH = VLF Spectroanalyzer, 866

SHC (Surrey High-resolution Camera), 543

SHF = Passive MW Radiometer (CIS), 695

SHOALS = Scanning Hydrographic Operational Airborne Lidar Survey, 1792

SHOOT (Superfluid Helium On-Orbit Transfer), 61

SI-GDR =Spectrometer/Interferometer (GDR sensor), 695

SIGI (Space Integrated GPS/INS), 152, 787

SII (Suprathermal Ion Instrument), 1126

SILEX (Semiconductor Intersatellite Link Experiment), 58, 523, 1015

SILVACAM =Real-time False Color CCD Video Camera, 1794

SIM (Spectral Irradiance Monitor), 240 SIMS = Chemical and Isotopic Measure

ments of Micrometeoroids by Secondary Ion Mass Spectrometry, 833

SIR (Scanning Infrared Radiometer), 1822

SIR (SMARTl Infrared Spectrometer), 1108

SIRAL (SAR Interferometer Radar Altimeter), 138, 562

SIRS (Satellite Infrared Spectrometer), 737, 1079, 1081

SIS = Scanning Imaging Spectrometer, 1566

SIS = Solar Isotope Spectrometer, 864 SIS = Star Imaging System, 537 SIT (Suprathermal Ion Telescope), 970 SKA-1 =3-D Ion Distribution Measure-

ment, 928

SKA-2 = Spectrometric Device Complex, 929

SKA-3 = Electron/Proton Distribution Experiment, 927

SKDR (S/Ka-band Data Relay), 1015

SKL = Solar Cosmic Ray Spectrometer Complex, 891

SLAR (Side-Looking Airborne Radar, NLR), 1795, 1885

SLAR (Side-Looking Airborne Radar), 1733

SLRRE (Satellite Laser Ranging Retroreflector Experiment), 1184

SM =Multichannel Spectrometer, 697, 700

SMAG (Scientific Magnetometer), 433

SMARD (Shape-Memory Actuated Release Device), 1049

SMATTE (Shape Memory Alloy Thermal Tailoring Experiment), 1052

SMEI (Solar Mass Ejection Imager), 199 SMIFTS = Spatially Modulated Imaging

FTS, 24, 53, 1796 SMILES (Superconducting Submillime

ter-wave Limb Emission Sounder), 28, 63,992


SMIRR = Shuttle Multispectral Infrared Reflectance Radiometer, 848

SMMR = Scanning Multichannel Microwave Radiometer, 510, 737, 1089, 1246, 1869, 1888, 1893

further mention, 737 SMR =Sub-Millimeter-wave Radiome

ter, 223

SMS (Submillimeterwave Sensor), 1543, 1817

SMS = Suprathermal Ion Mass Spectrometer, 904

SMS = SWICS + STICS, 982 SMX-1 (Spare Mircoprocessor Experi

ment), 1119 SMX-2 (Spare Microprocessor Experi

ment-2), 1120

SOAR (SIGI Operational Attitude Readiness), 152

SODISM (Solar Diameter Imager and Surface Mapper), 120, 1069

SOFIS (Solar-Occultation FTS for Inclined-orbit Satellite), 48, 216

SOL-ACES (Solar Auto-Calibrating EUV!UV Spectrophotometers), 120, 996

Solar Cell Diagnostic, 898 Solar Image Radiometer (EXOS-C), 901

Solar UV Monitor (SME), 944 Solar Wind Concentrator, 911 Solar-A (Solar Monitoring Observatory),

120,994 SOLCON = Solar Constant Sensor, 822,

827,853,1298 SOLSPEC (Solar Spectral Irradiance

Measurements), 120, 996 SOLSPEC =Solar Spectrum Measure

ment, 822, 853, 1298 SOLSTICE = Solar Stellar Irradiance

Comparison Experiment, 238, 261, 1861

Sony DXC-750 3-CCD Video Camera, 1539

SOR (Starfire Optical Reflectors, 1053 SORS = Solar Radiospectrometer, 891,

893 SOSNA-2 =Dosimeter, 929

SOSP =Solar Spectrum Instrument, 119, 828

SOT (Solar Optical Telescope), 963 SOUP = Solar Optical Universal Polari

meter, 1297, 1464 SOYA= Solar Constant and Variability

Instrument, 119, 827 SOVAP (Solar Constant Variability, Pi

card), 120, 1070 SOVIM (Solar Variability and Irradiance

Monitor), 120, 994 SOXS (Soft X-Ray Spectrometer), 942 SPACE = Spacecraft Particle Correlator

Experiment (UKS), 875 Space Fluid Experiment Device, 1104 SPADUS (Space Dust Experiment), 1009 SPE-1 = High Energy Particles Experi-

ment, 867 SPECK (Spectrophotometer), 1147 SPEDE (Spacecraft Potential, Electron

and Dust Experiment), 1107 SPIM (Spectrographic Imager), 1060 SPIRIT-III (Spatial Infrared Imaging

Telescope), 1058 SPM (Solar Proton Monitor), 731, 732 SPM (Sunphotmeter), 959 SPM = Solar Proton Monitor, 737 SPRE (SPARTAN Packet Radio Experi-

ment), 846

SPRITE (Signal Processing In The Element), 51, 1214

SPS (Space Physics Sensor), 438 SPT (Stationary Plasma Thruster), 1106,

1289 SPW = Stimulated Plasma Wave Experi

ment, 899 SQUID (Superconducting Quantum In-

terference Device), 586 SR (Scanning Radiometer), 731, 732 SR = Scanning Radiometer, 737 SREM (Standard Radiation Environment

Monitor), 580, 1098, 1119 SSALT =Single-Frequency Solid-State

Altimeter, 603, 1917 SSB = Gamma Tracker (DMSP), 673 SSB/A =X-Ray Spectrometer (DMSP),

674


SSB/0 = Omnidirectional Gamma Detector (DMSP), 674

SSB/S =Scanning X-Ray Detector (DMSP), 674

SSB/X-2 =Gamma Ray Particle Detector, 670

SSC = Snow Cloud Discriminator (DMSP), 674

SSCC (Spin-Scan Cloudcover Camera), 113,737

SSD = Atmospheric Density Sensor (DMSP), 674

SSDRE = Solid-State Data Recorder Experiment, 540

SSE = Temperature Sounder (DMSP), 673

SSH = Infrared Spectrometer (DMSP), 674

SSH-2 =Infrared Temperature and Moisture Sounder, 674

SSI/E = Topside Ionospheric Plasma Monitor (DMSP), 673

SSI/ES-2 = Special Sensor Ionospheric Plasma Drift/Scintillation Monitor, 669

SSI/ES-3 = Enhanced Ionospheric Plasma Drift/Scintillation Monitor, 670

SSJ = Auroral Electron and Ion Spectrometer, 673

SSJ* = Space Radiation Dosimeter (DMSP), 674

SSJ/4 = Precipitation Electron/Proton Spectrometer, 669

SSJ/5 = Precipitation Electron/Proton Spectrometer, 669

SSL = Lightning Detector (DMSP), 673

SSM = Triaxial Fluxgate Magnetometer, 669

SSM/I = Special Sensor Microwave Imager,665, 716,1246,1853,1855,1869, 1870, 1874, 1877, 1881, 1882, 1891, 1892, 1903, 1906, 1917

SSM/T = Temperature Sounder (DMSP), 1246

SSM/T-1 (Special Sensor Microwave Temperature Sounder), 666

SSM/T-2 (Special Sensor Microwave Water Vapor Profiler-2), 666

SSM/T-2 = Special Sensor Microwave Water Vapor Profiler-2, 1903

SSM-Boom =Triaxial Flux Gate Magnetometer, 670

SSMIS (Special Sensor Microwave Imager Sounder), 44, 667, 716, 1557

SSNI (Data Collection System), 893

SSPSR (Small Satellite Power System Regulator), 492, 1102

SSR (Solid State data Recorder), 1047

SSTI (Satellite to Satellite Tracking Instrument), 130, 578, 580

SSTR = Sea Surface Temperature Radiometer, 1812, 1856, 1917

SSU = Stratospheric Sounding Unit, 735, 743

further consideration, 737

SSULI = Special Sensor Ultraviolet Limb Imager, 670, 1011

SSUSI = Special Sensor Ultraviolet Spectrographic Imager, 672

SSZ = Laser Threat Detector, 670

STAFF= Spatio-Temporal Analysis of Field Fluctuations, 883

STAR (Space Three-axis Accelerometer for Research mission), 557, 1066

STAR = Sea-Ice and Terrain Assessment Radar, 31, 1813

STE (Supra thermal Electron Telescope), 969

STICS = Mass Sensor and Suprathermal Ion Composition Study, 982

STR =Scanning TV Radiometer (GOMS sensor), 632

SUFR-Sp-C = Solar UV Radiometer, 891,893

SULEICA = Suprathermal Energy Ionic Charge Analyzer (IRM), 874

SUMAS (Submillimeter Atmospheric Sounder), 1817, 1863

SUMER = Solar UV Emitted Radiation, 956

SUMO (Superconducting Microwave Oscillator), 996

Sunphotometer, 1818


SuperSTAR (Super Space Three-axis Accelerometer for Research mission), 589, 1066

SUPEX (Superconductivity Experiment), 1183

SUSIM = Solar Ultraviolet Spectral Irradiance Monitor, 1297

SUSIM =Solar Ultraviolet Spectral Irra-diance Monitor, 261, 822

Svetozar-3 Lidar, 1790

SVS (Space Vision System), 144

SWAN = Solar-Wind Anisotropies, 958

SWAVES (STEREO/WAVES), 970

SWE = Solar Wind Experiment, 982

SWEA (Solar Wind Electron Analyzer), 968

SWEPAM = Solar Wind Electron, Proton, and Alpha Monitor, 864

SWICS = Solar Wind Ion Composition Spectrometer, 864

SWICS = Solar Wind Ion Composition Study, 982

SWICS= Solar Wind Ion Composition Spectrometer, 977

SWIFT (Stratospheric Wind Interferometer For Transport studies), 218, 711

SWIMS = Solar Wind Ion Mass Spectrometer, 863

SWOOPS = Solar Wind Observations Over the Poles of the Sun, 977

SXI =Solar X-Ray Imager, 620, 626

SXP (Solar X-ray Photometer), 1172

SXR =Soft X-Ray spectrometer, 1176

SXT =Soft X-Ray Telescope, 951, 960

T T + DRE (Tracking and Data Relay Ex

periment), 737, 1086

TANS Vector (Trimble Advanced Naviga-tion Sensor), 785

TBB (Triband Beacon Transmitter), 232

TCS (Trajectory Control Sensor), 152, 820

TDDR (Total Diffuse Direct Radiome-ter), 1779

TDE (Total Dose Effect), 433

TDE = Total Dose Experiment, 534, 535, 538

TDLHS =Tunable Diode Laser Heterodyne Spectrometer, 1757

TDR (Tail-mounted Doppler Radar), 1751, 1860, 1912

TEAMS= Time-of-Flight Energy Angle Mass Spectrograph, 948

TECHS (Thermal Electron Capped Hemisphere Spectrometer), 1126

TED = Thermal Electron Detectors, 904

TED = Total Energy Detector, 735, 737, 744, 752

Telemetry Experiment, 1166

TEREK-C =Solar X-Ray Telescope/Coronograph (Coronas), 889, 893

TES (Tropospheric Emission Spectrometer), 395

TESS (Tomographic EUV Spectrograph System), 1173

TEXAS (Technology Experiment Augmenting Spartan), 845

TGRS = Transient Gamma Ray Spectrometer, 982

THD (Tunneling Horizon Detector), 1165

THERMO = Thermal Radiometer, 1734

THIR (Temperature-Humidity Infrared Radiometer), 737, 1081, 1084, 1086, 1090

THOMAS (THz OH Measurement Airborne Sounder), 28, 40, 1817, 1819, 1861

Three-Axis Fluxgate Magnetometer, 1019

TICCE = Timeband Capture Cell Experiment, 827

TIDE/PSI = Thermal Ion Dynamics Experiment/Plasma Source Investigation, 937

TIDI = TIMED Doppler Interferometer, 244

TIM (Total Irradiance Monitor), 238, 719

TIMAS = Toroidal Imaging Mass-Angle Spectrograph, 937

TIMS = Thermal Imaging Multispectral Scanner, 1597


TIMS = Thermal Infrared Multispectral Scanner, 1609, 1615, 1869, 1877, 1880, 1890, 1894

TIP (Tiny Ionosphere Photometer), 232

TM =Thematic Mapper, 444, 1310 further mention, 383, 1864, 1869, 1870,

1877, 1890, 1901

TMI = TRMM Microwave Imager, 257, 716, 1903

TMR= Topex Microwave Radiometer, 602, 1246, 1917

TMS = Thematic Mapper Simulator (NS001), 1707, 1758, 1864, 1869, 1894

TOMS = Total Ozone Mapping Spectrometer, 245, 246, 332, 696, 821, 1076

further considerations, 47, 697, 700, 737, 1089, 1840, 1863, 1879, 1905, 1910

TOMS-5 (Total Ozone Mapping Spectrometer), 248

TOPOSYS (Scanning Laser System), 1819

TOPSAR =Interferometric Radar Topographic Mapping Instrument, 31, 1527, 1908

Topside Ionospheric Plasma Sounder (EXOS-C), 901

TOYS = TIROS Operational Vertical Sounder, 734, 737, 1840, 1846, 1851, 1855, 1863, 1870, 1879, 1892, 1917

TPS (Total Pressure Sensor), 1064

TQCM (Temperature-controlled Quartz Crystal Microbalance), 1064

TQMS (Triple Quadrupole Mass Spectrometer), 1515

TRACE (Transition Region and Coronal Explorer), 950

Trasser-0 (Polarization Spectroradiometer), 473

TRAVERS = Sideview Radar System, 30, 479, 1000

TRSR (TurboRogue Space Receiver), 46, 556,590,600,1180

TRWIS = TRW Imaging Spectrometer, 1820

TSC (Terrestrial Solar Cells), 1046

TSCC (Tilt Scan CCD Camera), 1821, 1850, 1870, 1901, 1902, 1917

TSIS (Total Solar Irradiance Sensor), 120, 719

TTS = Target Tracking System, 1542 TV = TV instrument (framing tech

nique), 695, 700 TV = TV optical instrument (MR-600A),

693 TV Camera = Priroda optical instrument,

482 TV-MA (Television-Medium Angle), 723 TV-NA (Television-Narrow Angle), 721 TV-WA (Television-Wide Angle), 721

TVS (TV System), 19 TWERLE (Tropical Wind Energy conver

sion and Reference Level Experiment), 80, 1086

u UAV-AERI (UAV Atmospheric Emitted

Radiance Interferometer), 53, 1628, 1764

UCB =Extreme Ultraviolet Cosmic Background Explorer, 454

UEM-2 =Electron Accelerator, 876

UF-3K = Photometer, 876 UFSIPS = Radiation Emission Experi

ment, 928 UHCRE =Ultra High Cosmic Ray Ex

periment, 833 UHF Radiometer, 346 UK-10 (Electron Bombardment Ioniza

tion Thruster), 1288 ULEIS = Ultra-low Energy Isotope

Spectrometer, 864 UMMCI (University of Michigan Multi

channel Chemiluminescence Instrument), 1824

UPM = Neutral Plasma Accelerator, 876

URAP = Unified Radio and PlasmaWave Experiment, 977

USA (Unconventional Stellar Aspect), 1008

UV Auroral TV Camera (EXOS-A), 898 UV Glow Spectrophotometer (Exos-A),

899


UV Ozone Experiment (SME), 943 UV Spectrometer (EXOS-C), 901

UV-DIAL, 1755, 1859 UVAI = UV Auroral Imager, 928

UVCS (Ultraviolet Coronal Spectrome-ter), 844

UVCS = UV Coronograph Spectrometer, 957

UVI = Ultraviolet Imager, 939

UVISI (UltravioletNisible Imaging and Spectrographic Imaging), 1060

UVISI Imagers, 1062

UVNO (Ultraviolet Nitric-Oxide Experiment), 180

UVS (Ultraviolet Spectrometer), 1171 UVSP = Ultraviolet Spectrometer and

Polarimeter, 954

v V1 = Electric Field Experiment (Viking),

978

V2 = Magnetic Field Experiment (Viking), 979

V3 = Hot Plasma/Energetic Particle Experiment (Viking), 979

V4H =High-Frequency Wave Experiment (Viking), 980

V4L =Low-Frequency Wave Experiment (Viking), 980

V5 =Auroral Imaging Experiment (Viking), 980

VAE (Visible Airglow Experiment), 180 V APS (Vertical Air Profiling System),

1754 VAS= VISSR Atmospheric Sounder,

616, 737, 1869 VDP = 3-D Ion Faraday Cups, 928

Vector Magnetometer, 599 Vector Magnetometer (Magsat), 595 VEFI = Vector Electric Field Instrument,

204 VEGETATION = Spot-4 sensor, 16, 522

VGS (Video Guidance Sensor), 845 VHRR (Very High Resolution Radiome-

ter), 732

VHRR = Very High-Resolution Radiometer (INSAT sensor), 634

VHRR/2 (Very High Resolution Radiom-eter), 637

Video (Video Camera System), 1734 Vidicon TV Camera, 349

VIFIS = Variable Interference Filter Imaging Spectrometer, 24, 1825

VIIRS (Visible/Infrared Imager and Radiometer Suite), 82, 710, 713

VIRGO = Variability of Solar Irradiance and Gravity Oscillations, 119, 959

VIRL = Visible and near Infrared Lidar, 1827, 1917

VIRR = Visible and Infrared Radiome-ter, 511

VIRS = Visible Infrared Scanner, 256 VIS = Video Imaging System, 1828 VIS = Visible Imaging System, 940 Visible Nitrogen Experiment (SME), 944 VISS (Vibration, Isolation, Suppression

and Steering System), 1136 VISSR = Visible Infrared Spin Scan Ra

diometer, 612, 616, 643 further mention, 737

Visual Light Spectrometer, 1192 VLF = Very Low Frequency Wave Detec

tors, 899, 902 VLF = Very-Low Frequency Generator,

865 VLF-2 = Very-Low Frequency Generator

2,867 VMAG (three-axis fluxgate magnetome

ter), 261 VMC (Visual Monitoring Camera), 1100 VMI (Vegetation Monitoring Instrument),

522 VNIRI (Visible Near Infrared Imager),

236 VTIR = Visible and Thermal Infrared

Radiometer, 459 VTPR (Vertical Temperature Profile Ra

diometer), 732 VTPR =Vertical Temperature Profile Ra

diometer, 737 VTS (Visual Telemetry System), 20, 145,

1100, 1122


VUSS = Vacuum UV Solar Spectrometer, 891, 893

w WAAC (Wide-Angle Airborne Camera),

1830

WAC (Wide Angle Camera), 543

WAOSS (Wide-Angle Optoelectronic Stereo Scanner), 1829

WAOSS-B (Wide-Angle Optoelectronic Stereo Scanner), 801

WARP (Wideband Advanced Recorder Processor), 1031

WAS (Whole Air Sampler), 1574

WASS (Wide Angle Star Sensor), 1099

Water Vapor I Temperature Sensor, 1571

WATI = Wind and Temperature Spectrometer, 234

WATS =Wind and Temperature Spectrometer, 204

WAVES= Radio Plasma Wave Experi-ment, 981

WBD = Wide Band Data, 885

WBS =Wide-Band Spectrometer, 961

WEFAX = Weather Facsimile (a widely used retransmission service), 617, 646, 737

WFC (Wide-Field Camera), 209

WFI (Wide Field Imager), 1800, 1801

WFI = Wide-Field Imager, 17, 352, 353, 529

WHiRL = Wide-angle High-Resolution Line-imager, 1830

WHISPER = Waves of High Frequency and Sounder for Probing of Density by Relaxation, 884

Widefield Radiometer, 722, 723

WiFS = Wide Field Sensor, 16, 420, 421

Wild RC10, 1598, 1702, 1750

Wild RC10A, 1598, 1702

Wild RC20, 1702, 1750

WINDI = Wind Doppler Imaging Interferometer, 262, 1861

WINDRAD =Wind Radiometer, 1831

WindSat (Wind Microwave Radiometer), 197

WIS = Wedge Imaging Spectrometer, 24, 1381, 1832

WLC (White-light Coronagraph), 845

WOX (Water Ozone Experiment), 1671, 1856

WTE (Whale Tracker Experiment), 508

WVR = Water Vapor Radiometer, 575

X X-MIR Inspector, 145

X-RADAR (X-band Radar Instrument), 30,861

X-SAR (SAR for X-band Measurement, 851

XBT (Expendable Bathy-Thermograph), 1868, 1917

XDEX (X-Ray Detector Experiment), 1184

XF (Xenon Flashlamp), 1064

XIPS (Xenon Ion Propulsion System), 1286

XPAA (X-band Phased Array Antenna), 83, 1030

XPS (XUV Photometer System), 241

XRP =X-Ray Polychromator (=BCS+FCS), 954

XRS (X-Ray Spectrometer), 457

XRS = Solar X-Ray Sensor, 620

XRT (X-Ray Telescope), 1297, 1476

XSAR (X-band SAR instrument), 30, 293

XSM (X-ray Solar Monitor), 1107

XSM (X-ray Sky Monitor), 422

y YES (Young Engineers' Satellite), 1122

z ZL-A = Langmuir Probe Experiment,

867

ZL-A-S = Langmuir Probe, 868, 877

Appendix A Glossary

Documents