All rights reserved © 2005, Alcatel Alenia Space INFN LNF Frascati, 21-22 March 2006 backnext Page 1 Contribution of Alcatel Alenia Space Italia to fundamental

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All rights reserved © 2005, Alcatel Alenia Space

INFN LNF Frascati, 21-22 March 2006

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Contribution of Alcatel Alenia Space Italia

to fundamental physics space missions

Workshop

FUNDAMENTAL PHYSICS IN SPACE WITH SMALL PAYLOADS


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FUNDAMENTAL PHYSICS PROJECTS

AAS-I projects/activities relative to fundamental physics space missions

Lageos II satellite integration STEP (Satellite Test of the Equivalence Principle)

Two Phase A studies performed for ESA as prime contractor LISA (Laser Interferometer Space Antenna) for gravitational waves

detection Participation to the Phase A study with the responsibility of the design of the

optical bench and participation to the technology development of the laser source with the responsibility of the fiber delivery system

LPF (LISA Pathfinder) D&D of the Inertial Sensor Electrode Housing and Test Mass and of the Caging

Mechanism Assembly in the frame of LPF Implementation Phase GG (Galileo Galilei) mission for the test of the EP

Phase A study performed for ASI as main industrial contractor

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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

STEP

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Satellite design drivers of the STEP payload

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)

Mass: 1000 kg (P/L 260 kg)

Power: 450 W maximum

STEP

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LISA Phase A study (1999-2000)

Mission objective: Gravitational waves detection

AAS Role: Sub-Contractor (customer Astrium)AAS Specific Tasks: Optical bench

opto-mechanical design and analysis

P/L opto-electronics design coordination

Ultra-stable oscillator selection

Opticalbench

LISA

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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).

fiberpositioner

proof mass

vacuum wall

q1

qp1

w1w2

ps2 q3

p1

p2

s4m3

m2

l2

l4

l3

fiber 1

fiber 2

to the telescope

from the telescope

to bench 2

from bench 2

fromlaser source

s3

inertial sensor core

collimator

ps1q2

m1s1

bc1

bc2

s2

l1

CCD

l5

m4

p3

fibercoupler

ps3q4

350 mm

LISA

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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

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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.

LISA Pathfinder


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LISA Pathfinder ISS EH, TM, CM & CCU

EH: ELECTRODE HOUSING

CM: CAGING MECHANISM

CCU: CAGING CONTROL UNIT


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LISA Pathfinder EH & TM

ELECTRODES

FRAME

The LISA Electrode Housing provides the control, the sensing and the caging system interface for the inertial sensors (Test Masses)

Main technical challenges in EH• Special materials selection with low LTC,

low outgassing, extreme low magnetic impurity, etc

• Microns dimensional tolerance in machined subassemblies and assembling

Main technical challenges in TM• Very low susceptibility material with

extremely low magnetic impurities• Non standard Alloy Au/Pt casting• Dimensional tolerance in range of

microns• Special Optical Machining of specific Au/Pt

surface areas


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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

and

•one Caging Control Unit (CCU)

LISA Pathfinder - Caging Mechanism Assembly


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LISA Pathfinder CM

The Caging Mechanism shall perform pre-loading to the TM (Test Mass), being able to grab the TM in few tens seconds.

High pre-load: 3000 N

Medium pre-load: 300 N

Low pre-load: 1-20 N

Launch condition

Storage condition

Safe function (Grabbing, positioning and release)

CM +Z

CM -Z

TEST MASSFINGERS


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CMSS fingers

View of one of the two CMs

reservoirs

Piezo-pumpPiezo-valves

GPRM plunger

Hydraulicactuators

LISA Pathfinder CM


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View of GPRMs acting on the TM

With CMSS fingers in “retracted position”, the GPRM plungers act on the TM to perform grabbing and positioning

GPRM plungers

Test Mass (TM)

LISA Pathfinder CM


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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

Galileo Galilei (GG)

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Key issues of the GG satellite 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)


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GG payload is based on a fast rotating, high sensitivity differential accelerometer operating in ambient conditions

AAS contributed to GG Instrument Study for:• Instrument electronics study:EP acquisition chain PGB & Test Masses whirling/axial controlPGB & Test Masses E-static dampers

• Instrument thermal and mechanics study:Pico Gravity Box Test Masses suspension and adjustmentInchworm controlLock/Unlock mechanism

• FEEP electronics study:Emitter HVPS (3 to 5 kV)Accelerator HVPS (-2 to -5kV)Neutraliser PS



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GGG - Galileo Galilei on Ground

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


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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

Radioscience Instrumentation

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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

GOCE

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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


Laser Doppler Interferometry

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Laser metrology for Basic Angle monitoring in GAIA mission Technology study (2004-06), AAS-I Prime Contractor,

Customer ESA

Laser metrology based on Fabry-Perot interferometers with 1e-12 m resolution over 1 m distance).Configuration of the GAIA astrometric

telescope with the network of metrology lines

Breadboard of a single metrology line


Laser metrology

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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

Facility

Intrinsic force

measurement noise of the Nanobalance

NANOBALANCE FACILITY

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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

Application Perspectives: GAIA, Proba 3, LISA, DARWINT

T

GN2T

T

GN2

StorageAssembly

Pressure RegulationAssembly

HP fill & ventvalve

HP Transducers

LP Transducer

Filter

Pressure Regulator(HP PV valve + LPTransducer)

ThrustActuationAssemblyLP PVN

Valves

Filter

ControlElectronics

LP fill & ventvalve

Mass FlowSensors

MassFlowSensors

HP PV valve

LP PVvalves

Relief valve

ControlElectronics

Module 2

ControlElectronics

Module 1

Engineered S-MFS

HP PV Engineering model LP PVN 1st prototype

S-MFS configuration with a heater and two thermopiles

Micro-Propulsion Cold Gas Thruster


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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


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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.

Instrumentation for Radioscience Experiments

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AAS Science Projects Overview

Heritage Present Future

•Meteosat•Spot - Vegetation•ERS1-2•ISO•Lageos•SAX•Huygens•Helios1•Envisat :PDS•Envisat :Meris - ASAR•Topex-Poseidon•Jason1•Clementine•MSG1•Hélios 2•Integral•Rosetta•Venus Express•Mars Express•Newton-XMM

•MSG 2,3,4•Herschel•Planck•Cryosat - Siral•MetOp : IASI•MetOp: EPS•GOCE•Calipso•Pléiades•Corot•SMOS•Jason 2•Microscope•Lisa Patfinder•Agile

•Bepi Colombo•Interplanetary missions•Aurora: Exomars, MSR•Earthcare•Sentinels•Simbol’X-Pegase•Galileo Galilei•Solar Orbiter•MTG•Darwin•Xeus•Space Weather•Pleiades GS•post Hélios2•Export•Hypseo•Sabrina•LISA

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All rights reserved © 2005, Alcatel Alenia Space INFN LNF Frascati, 21-22 March 2006 backnext Page 1 Contribution of Alcatel Alenia Space Italia to fundamental