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Space Solar Power Satellite Alternatives and Architectures.ppt | 1
Analysis, Modeling, Simulation and Experimentation
Space Solar Power SatelliteAlternatives and ArchitecturesSeth Potter, Martin Bayer, Dean Davis, Andrew Born,David McCormick, Louanna Dorazio, Pinal PatelThe Boeing Company, El Segundo and Huntington Beach, CA
AIAA Aerospace Sciences MeetingOrlando, Florida5-8 January 2009
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Historical Background
Deploy large solar arrays in Earth orbit (typicallygeostationary) and beam power to receiver arrays on the
ground – Microwave beams most extensively studied, but there is anincreasing interest in lasers
Concept proposed by Dr. Peter Glaser of Arthur D. LittleCorp. in 1968 and studied by NASA and US Department of
Energy during the 1970s – Contractors included Boeing, Rockwell International, and Spectrolab
NASA and industry have studied the concept intermittentlyduring the 1990s and early 2000s
System sizes are huge (solar arrays several thousand metersacross; power levels of thousands of megawatts) – Due to the divergence of the microwave beam, a large amount of
power must be collected to achieve an economically recoverable
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Model 1: Size of Receiver Array
Array sized to mainbeam lobe collects84% of total power
Normalized BeamIntensity
Distance fromCenter
of Beam Pattern(arbitrary units)
meters.inalle.g.,;units
samein the bemust parameters: Note
orbit) byd(determineantennas betweendistancex
beamof hwavelengtλ
antennareceivingof diameter D
antennaingtransmittof diameter D
where
2.44xλ
DD
r
t
r t
=
=
=
=
=
Vertical scale
expanded to showsidelobes
For a given beam wavelength, transmitting antenna size, and distance to receiver,beam diameter at the receiver is independent of amount of power transmitted.
For a given beam wavelength, transmitting antenna size, and distance to receiver,
beam diameter at the receiver is independent of amount of power transmitted.
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Model 1: Calculation of Beam Intensity
where
I 0
= peak beam intensity
Pt = transmitted power
Dt = diameter of transmitting antenna
λ = wavelength
x = distance between antennas
2
0 4 ⎭⎬
⎫
⎩⎨
⎧=
x
DP I
t t
λ
π
Typically, bean intensity will be a requirement determined by physical andenvironmental constraints, and the transmitting antenna will be sized to focus the
energy to this intensity.
Typically, bean intensity will be a requirement determined by physical andenvironmental constraints, and the transmitting antenna will be sized to focus the
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Military Mission Needs: Recent Developments
From the NSSO Report:
Recommendation: The SBSP Study Group recommends
that the U.S. Government should sponsor a formally funded,follow-on architecture study with industry and international partners that could lead to a competition for an orbital demonstration of the key underlying technologies and
systems needed for an initial 5-50 MWe continuous SBSP system.
Discussions at the NSSO SBSP meeting in 9/07 emphasizedpower levels of 5-15 MW at forward military bases having
available land parcels of ~1000 meters in width to support arectenna array
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Civil Government Installation:Example – Amundsen-Scott South Pole Station
Characteristics (Source:http://www.nsf.gov/od/opp/support/southp.jsp): – Diurnal cycle is annual, i.e., 6 months of daylight, 6 months of darkness
– Elevation: 2,835 meters (9,306 feet) – Temperature range: -13.6°C to -82.8°C. Annual mean is -49°C; monthly means vary
from -28°C in December to -60°C in July. Average wind is 10.7 knots (12.3 miles perhour); peak gust recorded was 48 knots (55 miles per hour) in August 1989.
– Snow accumulation is about 20 centimeters (6-8 centimeters water equivalent) per
year, with very low humidity. Population of Station:
– Summer: 150 people
– Winter: 50 people
Power consumption scaled from military bases at 3 kW/person – Summer: 150 people x 3 kW/person = 450 kW
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
20 40 60 80
20
40
60
80
Beam Angles
deg
S a t e l l i t e E
l e v a t i o n A n g l e
A n
g l e f r o m
Z e n i t h
Latitude (deg)
Is SSP Feasible for a South Pole Base?
GEO satellites are not visible at the poles, and are below the horizon forany latitude poleward of ± 81° – LEO and MEO satellites will not be visible at the poles for low orbital inclinations
Molniya orbits have been used for communications access to high latitudes – Highly elliptical with apogeeover a pole
– Our analysis suggests that accesstimes from a Molniya satellite to a
polar station would be good
Microwave transmitting antennawould be impractically large,for the amount of powerdelivered
Laser power beaming would
have to be used.
The power requirements of a polar research facility can be met by a smallsolar power satellite in a Molniya orbit using laser power transmission.
The power requirements of a polar research facility can be met by a small
solar power satellite in a Molniya orbit using laser power transmission.
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Time-Averaged Global Electric Power Generation Capacity
1,291.71,440.3
1,667.7
1,978.4
2,395.4
2,784.9
3,134.2
3,467.9
3,794.6
0
1 , 0
0 0
2 , 0
0 0
3 , 0
0 0
4 , 0
0 0
1990 1995 2000 2005 2010 2015 2020 2025 2030
Year
T i m e - A v e r a g e
d P o w e r G e n e r a t i o
n C a p a c i t y
( G W )
History Projections
To meet 10% of future global electricity requirements, 20 GW of SSP capacity must bedeployed per year. Our model computes mass launch requirements from this.
To meet 10% of future global electricity requirements, 20 GW of SSP capacity must be
deployed per year. Our model computes mass launch requirements from this.
Data Source: U.S. Energy Information Administration, Report #:DOE/EIA-0484(2008), September 2008.
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Low Earth Orbit (LEO) Power Beaming
Example orbit: 350 km circular, 51.6°inclination – ISS-like, so results traceable toISS or Shuttle-to-ground demos
Illustration shows access to Goldstone
Satellite accesses ground station for 5 to 10 minutes at a time during 8 of the ~16daily orbits if no minimum elevation angle constraint is set
For 10°minimum elevation angle,then the accesses are 6 minuteseach with two accesses per day
For 30°minimum elevation angle,there are still two satellite accessesper day, lasting only 2½ minuteseach
A low Earth orbit at ISS altitude may provide sufficient ground station access time for demos, butmany would have to be deployed to beam power continuously to customers.
A low Earth orbit at ISS altitude may provide sufficient ground station access time for demos, but
many would have to be deployed to beam power continuously to customers.
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Medium Earth Orbit (MEO) – Coverage of aSingle Satellite
An equatorial MEO SPS in a 12,000-km circular orbit (6-hour 53-minute orbital period)may be able to serve tropical and lower temperate latitudes
Satellite would be in sunlight continuously around the solstices
Around the equinoxes, the satellites are in eclipse for 46 minutes during each orbit
From the lower left figure, the satellite would appear to cover middle latitudes such asthe continental US. However, the elevation angle contours shown are an instantaneoussnapshot of a non-geostationary satellite, so access times could be relatively short.
Instantaneous elevation angle contours for an SPS in a 12,000 kmequatorial orbit. Note: the 3-D contours do not represent the beam.
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Geostationary Orbits
Geostationary orbits (GEO) have an altitude of 35,786 km and arecircular (or nearly so) and have an inclination of 0°(or nearly so),that is they are equatorial
Minimizes scanning losses of satellites in lower orbits that mustcontinuously slew their beam to maintain power transmission tothe ground site
Launch to geostationary orbit from Earth is more costly than low
orbits, but may actually be less costly than some medium Earthorbits because the latter may have higher inclinations
The main disadvantage of GEO is that the divergence of the beamover such a long distance drives SSP system sizes up
– GEO orbits have usually been considered the default orbits for solar powersatellites, though more recent studies have considered lower orbits toachieve smaller system sizes and lower costs to first power
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Notional Mass of Geostationary Solar Power Satellites
A single solar power satellite in geostationary orbit can supply several thousand MW of power tothe Earth. Many such satellites can supply a significant portion of the world’s electricity needs.
A single solar power satellite in geostationary orbit can supply several thousand MW of power to
the Earth. Many such satellites can supply a significant portion of the world’s electricity needs.
0
5K
10K
15K
20K
25K
30K
35K
40K
45K
50K
55K
60K
65K
70K
0 2500 5000 7500 10000
M a s s_
S S P S_
t o n s ,
t
Transmitted_Power, MW
M a s s ,
t h o u s a n
d s o f m e t r i c t o n n e s
Transmitted Power, MW
Minimum feasible powerlevel decreases with
increasing frequency
High power levels: massand cost driven by solararray
Low power levels: massand cost driven bytransmitting antenna
Frequency2.455.810
20.235
Frequencies are in GHz
For a 5 GW GEO SPS, theinstallation cost (includinglaunch) is about $240 perwatt
Still too high to becompetitive with otherenergy sources for baseload
commercial power
System size too large forsmall niche markets, sizecould be reduced with laser
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Advanced Systems | Analysis, Modeling, Simulation and Experimentation
Space Solar Power Advantages
Lower environmental footprint compared to fossil fuels
Lower land use per unit power compared to other renewables
Synergy with other energy sources
– Space solar power microwave rectennas can be designed to let light passthrough, so the same land area can be used for conventional solar power – or possibly agriculture
– Solar power satellites using laser power transmission may be able tosupply extra illumination to already-existing conventional solar power plants
Synergy with space exploration and development
– SSP can use resources from space, particularly the Moon
– Near-term space missions can test and demonstrate SSP technology andprospect for non-terrestrial resources to be used for SSP in a mannerconsistent with the current plans for Project Constellation
SSP may be an economic driver for commercial spacedevelopment