Contribution of Alcatel Alenia Space Italia to fundamental physics space missions Workshop FUNDAMENTAL PHYSICS IN SPACE WITH SMALL PAYLOADS INFN LNF Frascati, 21-23 March 2006. FUNDAMENTAL PHYSICS PROJECTS. AAS-I projects/activities relative to fundamental physics space missions - PowerPoint PPT Presentation
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Satellite Test of Equivalence Principle (STEP) Phase A studies (1993, 1996)
Mission objective: Verification of the EP within 1 part in 1018
AAS Role: Prime Contractor (customer ESA)
AAS Specific Tasks:
System requirements and spacecraft design Spacecraft-instrument interface design Modelling and analysis of the enviromental disturbance (air drag, magnetic field, self-gravity,..) impacts on the EP measurements
Cryogenic environment necessary to operate the differential accelerometers liquid helium cryostat, limited lifetime (6 months)
Low Earth Orbit (400 km) required to get a large driving accelerations on the proof masses “drag-free” control system operated with proportional thrusters fed by the helium evaporated from the cryostat
Ultra sensitive accelerometers minimization of any coupling with the spacecraft generated disturbances (self-gravity, tides of the helium in the cryostat)
Key issues of the LISA optical bench design Ultra-high dimensional stability required by the laser interferometer the
bench was designed in glass material (ULE) with very low coefficient of thermal expansion; a novel technique (hydroxy-catalysis bonding) was taken into account to be used for “gluing” the optical elements on the bench surface; the mechanical interfaces should minimize the stress on the glass.
The optical elements must be designed and realized to minimize the laser beam wavefront distortions and the straylight on the detectors (at the level of few picoW).
High Stability Laser for Space interferometry (2001)Objective: Development of the LISA laser source stabilized in power, frequencyAAS Role: Sub-Contractor (customer Astrium)AAS Specific Tasks: Fiber delivery system (laser source to optical bench) design, procurement, test
LISA Pathfinder is a technology demonstration mission for LISA, with a single Spacecraft hosting the LISA Test Package (LTP); LTP is the squeezing of one LISA interferometer arm from 5x106Km to few tens cm, within a single S/C and is constituted mainly by 2 Inertial Sensors and the Optical Metrology S/S.
Within the Inertial Sensor, in the frame of LPF Implementation Phase, AAS-I is presently in charge of design and development of: •the EH: Electrodes Housing•the TM: Test Masses as subcontractor of the Inertial Sensor Prime
the CMA (Caging Mechanism Assembly), i.e. the Caging Mechanism and Caging Control Unit (ESA Customer)
under the scientific lead of S. Vitale (TN Univ.), the LTP architect.
Caging MechanismTwo (+Z and –Z) mechanisms shall provide the capability to:
• constrain the TM, which resides in the Electrode Housing (EH) in a defined position during launch. • move the TM into a precise position from where it shall be separated from the CM by retracting the CM device from the TM surface with minimum forces (and consequently minimum residual velocity) on the TM; • capture the free falling TM within the electrode housing once released from stowed position and to store the TM in its stowed position again.
To accomplish the above tasks, the CMA is implemented by two sub-mechanisms:
• the CMSS (Caging Mechanism Subsystem), to hold the TM in place during launch and until the beginning of the flight operations
• the GPRM (Grabbing, Positioning and Release Mechanism), to precisely grab, position and release the TM for scientific operations during flight
Galileo Galilei (GG) Phase A study (1998)Mission objective: Verification of the EP within 1 part in 1017
AAS Role: Main industrial contractor (customer ASI); instrument feasibility study under the scientific leading of P.I. A. Nobili (Pisa Univ.) AAS Specific Tasks:
System requirements and spacecraft design
Spacecraft-instrument interface design Attitude control system design and
analysis Drag-free control design and analysis Dynamic simulator of spacecraft and of the
payload (spinning differential accelerometer)
Instrument thermal, mechanical and electronics architectural design
Precise measurement of the rotation status of the satellite spinning at 2 Hz: 0.1% - 0.01%, to be performed by Earth and Sun sensors (star sensors not appropriate for such a high spin rate)
Drag-free control with FEEP micro-thrusters on a spinning satellite modulated mode operation required synchronized with the spin
Thermal decoupling between the satellite and the payload (operating at room temperature)
Satellite “miniaturisation” (mass limit = 300 kg for a launch with Pegasus)
A Galileo Galilei experimental prototype (GGG) has been implemented inside a vacuum chamber for a first on ground evaluation of the GG baseline hardware in view of the in-flight test on GG satellite
AAS-I/LABEN- Proel has provided a significant contribution the the GGG experiment both in terms of hw manufacturing and support for test set-up preparation and test running
GGG apparatus set-up, operated at the AAS-I Laben/Proel thermal-vacuum facilities in the years 2002 and 2003
AAS-I experience applicable to fundamental physics
Other projects/activities of AAS-I with technology developments applicable to fundamental physics missions in space GOCE (Gravity field and Ocean Circulation Explorer)
Drag free control; ultra-stable structure and thermal control for ultra-sensitive accelerometers; measurement model and error analysis/budget; end-to-end performance simulator.
Laser Doppler Interferometry Mission for Earth Gravity Field Design of laser interferometer for satellite-satellite distance measurement (~1 nm
over 10 km) referred to proof-masses of ultra-sensitive accelerometers; measurement model and error analysis/budget.
GAIA laser metrology Development of high stability optical bench Development of laser metrology for optics stability monitoring at pm level
Nanobalance Facility Test at sub-microN level of micro-thrusters for LISA Pathfinder, LISA, Microscope
Cold Gas Micropropulsion Thrusters, Neutralizers for FEEPs and EPDP Development of technologies for micropropulsion/electric propulsion
AAS-I experience applicable to fundamental physics
GOCE (Gravity field and Ocean Circulation Explorer) Project in Phase C/D, AAS-I Prime Contractor, Customer ESA Gravimetric mission with ultra-sensitive accelerometers (1e-12
m/s2) Drag-free control with ion thruster compensating the resual air drag
at 250 km
Main P/L instrument:
3-axis gradiometer made by six 3-axis accelerometers
Laser Doppler Interferometry Mission for Earth Gravity Field Feasibility study (2005), AAS-I Prime Contractor, Customer ESA
Gravimetric mission based on satellite-satellite tracking with a laser interferometer.
Drag-free control with ion thruster, laser metrology (1e-9 m resolution over 10 km), ultra-sensitive accelerometers on each satellite for non-gravitational acceleration measurement
10 km
The optical bench with the accelerometer and the laser interferometer
AAS-I experience applicable to fundamental physics
AAS-I experience applicable to fundamental physics
Nanobalance Facility Facility realized by AAS-I with Metrological Institute “G. Colonnetti”
and Polytechnic of Torino under ESA contract for the characterization of micro-thrusters, to be used for future space missions of fundamental physics (LISA Pathfinder, Microscope, LISA, GG) with a measurement res. < 0.1 microN
The Nanobalance Facility makes use of a Fabry-Perot laser interferometer. Nanobalance
Cold Gas Micro Propulsion Thruster (few uN to 1 mN) based on the Proportional Proportional Valve (PV)Valve (PV) and on Mass Flow SensorMass Flow Sensor (MFS)(MFS) under development
Neutralizers, utilized in the FEEP Micro Propulsion Subsystem of Microscope and Lisa Pathfinder, for neutralizing the produced ion beam and avoiding spacecraft charging;
Electric Propulsion Diagnostic Package (EPDP) already implemented on SMART1, candidate for LPF and potentially for Microscope
Neutralizers and EPDP for the FEEP Micropropulsion
Sketch of the Neutralizer operation in conjunction with a FEEP thruster
EM of the Neutralizer for the FEEP on Microscope/Lisa PFElectron Current up to 6 mA
3D Layout of Neutralizer for the FEEP on Microscope/Lisa PF
AAS-I experience applicable to fundamental physics
AAS-I experience applicable to fundamental physics
RF Subsystem in Ka-band for the Radio Science experiment in the Cassini–Huygens mission to Saturn (operative)
Future (on board MPO of Bepi Colombo Mission to Mercury): MORE (Mercury Orbiter Radio-science Experiment), P.I.: L. Iess Uni-
Roma1) a system level experiment for the study of the main geodetic and gravitational characteristics of Mercury and in addition the test of gravity theory.
The key instrument will be the Ka-band Transponder (KaT) and WBRS for precision ranging in the Ka/Ka channel link.
ISA (Italian Spring Accelerometer, P.I.: V.Iafolla(INAF-IFSI) a tri-axis accelerometer with accuracy of 10-9ms-2/√Hz in the band 3x10-5 to 10-
1 Hz
The data measured by ISA will be used to correct the MORE data from the non gravitational perturbations in the Mercury orbit, in particular to subtract the effects of the inertial accelerations.