microscope mission overview - oca
TRANSCRIPT
1 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
MICROSCOPE mission overview
Pierre Touboul , on behalf of the MICROSCOPE team
ONERA, The French Aerospace Lab, BP 80100, F- 91123 Palaiseau
Cnes Courtesy
2 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
UFF TEST RATIONALE
• UFF violation one of the invariance of the EEP (UFF, LPI, LLI) violated!
• MICROSCOPE Objective : 10-15 accuracy
• See T. Damour, P. Fayet, E. Fishbach, E. Adelberger, C. Lämmerzahl, L. Blanchet, S. Reynaud, Ph. Brax, B. Julia...
• Physics is not completely understood new Physics New experiments New type of results
• MICROSCOPE is the first accurate UFF test in space
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3 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Test of Universality of Free Fall : from initial experiments...
Galilée (1590)
•Initial conditions ?•Gravity gradients ?•Environment effects ?•Relative position measurement ?
•Initial conditions ?•Gravity gradients ?•Environment effects ?
No atmospheric drag•Relative position measurement ?
hammer and feather
Apollo 15 (1971)
David Scott, A. Worden, J. Irwin
4 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Torsion Balance Experiments: A Low-energy Frontier of Particle Physics, E. G. Adelberger et al., Prog. Part. Nucl. Phys 62, 102 (2009)
aN(Be) − aN(Ti) = ( +0.6 ± 3.1) × 10−15 m/s2
aW(Be) − aW(Ti) = (−2.5 ± 3.5) × 10−15 m/s2
η (Be,Ti) = ( +0.3 ± 1.8) × 10−13 in 75 days of dataaN(Be) − aN(Al) = (−2.6 ± 2.5) × 10−15 m/s2
aW(Be) − aW(Al) = ( +0.7 ± 2.5) × 10−15 m/s2
η (Be,Al) = (−1.5 ± 1.5) × 10−13 in 96 days of data
Fixed relative motion of the test masses & Measurement of the Torques
Laboratory tests : Eötwash group
Test of Universality of Free Fall : to present tests...see presentations by Eric Adelberger and François Mignard
E
M
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Lunar laser ranging• laser impulse 100ps & 1 photon detected back, for every 1020 emitted at every 100 pulses• relative motion of Earth and Moon in orbit around the Sun
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MoonI
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EarthI
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MM
MM
J. G. Williams, X. X. Newhall, and J. O. Dickey, Phys.Rev. D 53, 6730 (1996).
Earth gravity @ 700km ~ 8 ms-2
Sun gravity @ Earh ~ 1000 less
5 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Permanent pico-meter control of the 2 masses No fluctuations of the mass environment due to relative motion Centring initial and permanent conditions : 20 µm known at 0.1 µm in orbital plane (X,Z) Measurement = Necessary forces to control the same orbital motion Satellite impose the common motion : reduced instrument better operation
Galileo Galilei « Free fall » in space Microscope
TEST OF UNIVERSALITY OF FREE FALL and MICROSCOPE space experiment...
•Measurement = relative motion of the two masses in geodetic motion• satellite as a shield to the mass --> drag free null or weak stiffness between masses and satellite displacement of the satellite & instrument apparatus wrt masses fluctuations of the mass motion environment
2 test masses made of different composition Gravitational Source : the Earth Kinematic Acceleration : Orbital motion Identical initial conditions of motion
6 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
2 accurate test masses Dedicated space instrument = differential accelerometer One Differential accelerometer comprises 2 inertial electrostatic sensors 2 pairs of masses Pt-Pt & Pt-Ti 2 diff. accelero. double difference
Satellite with drag compensation & fine attitude control Fine passive thermal control and soft EM environment
Mission duration : 18 months – 2 years Heliosynchronous orbit, 700 km altitude; e < 5 10-3
MICROSCOPE space experiment
Pt
Ti
B/ Z/ (N-Z)/
1.008911 0.46309 0.082731.008009 0.40296 0.20208
Mass material : Pt and Ti alloys Nuclear properties
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EP test Axis
Material 1 (Pt)
Material 2 (Ti)
gravity field
kIk
Gk
mm
1
• centering• shape : spherical inertia, multipoles• material density homogeneity
• Angular acceleration & centrifugal acceleration : to be controlled• Coriolis stability of velocities • Cinematic relative acceleration stability of the configuration and control
7 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Different experiment conditions : Modulation of the gravity field in instrument frameInertial pointing with 2 directions : to the Earth @ node or normal fEP = forb = 1.68 10-4 HzRotating pointing with 2 frequencies : 73/20 forb & 97/20 forb fEP = forb+ fspin= 7.8 10-4 Hz & 9.8 10-4 Hz
Data Processing and Validation of the levels of the disturbing sourcesTest duration : series of 20 orbits 1.2 105 sSampling period : 0.25 s Signal to be observed at EP test phase & frequency rejection of stochastic and tone disturbing signals
Very accurate instrument calibration sensitivity matching / alignments / quadratic sensitivity corrections of the measurements
MICROSCOPE space experiment
EP test Axis
Material 1 (Pt)
Material 2 (Ti)
gravity field
8 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
The Measure
What do we measure ? Earth’s, satellite, instrument, physics contributions
see for details presentations by Gilles Métris, Agnès Levy, Emilie Hardy
Stochastic and Tone Signals to be considered with a limited observation period and some lacks of data Detailed Specifications for S/C Sub-Systems, Instrument Environment & Instrument Performances Accurate in orbit calibration A posteriori estimation and corrections
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)()(..2 ,,,,0, CouplMOgCorInTMK dndmeasquadcappdsatcddmeas
Measured Acceleration Difference
Bias differencelimited thermal
fluctuations
Common Mode Sensitivity Matrix (Inst. Scale Factor & Attitude,
Coupling)Estimated by calibration
or limited by construction
Earth Gravity gradient tensor
Computed with Model, S/C position & attitude
and Removed
Inertia Tensor (Angular Velocity and Acceleration)
Minimized by AOCSfrom SST & Inst. data
Differential Mode Sensitivity Matrix (Scale Factor
Mismatching & Misalignment)Estimated by calibration
Common mode acceleration
(S/C drag-free Control from Sensor common
data)
Instrumentnoises
&couplings
2 2
2 2
2 2
y z x y z x z y
x y z x z y z x
x z y y z x x y
In
dzdxdxdydy
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Coriolis & relative motion acceleration
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EP violation S
9 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Space Electrostatic accelerometersfor Earth gravity field recovery
CHAMP (CNES-DLR), July 2000- 2009 GRACE (NASA-JPL), March 2002 – 2015 ?
GOCE (ESA), March 2009 – May 2013 ?
• Γn: 3·10-9 ms-2 /Hz1/2
• Γmax: 10-4 ms-2
• [0.2·10-3; 10-1 ] Hz
• Γn: 3·10-9 ms-2 /Hz1/2
• Γmax: 10-4 ms-2
• [0.2·10-3; 10-1 ] Hz
• Γn: 1.0·10-10 ms-2 /Hz1/2
• Γmax: 510-5 ms-2
• [0.1·10-3; 10-1 ] Hz
• Γn: 1.0·10-10 ms-2 /Hz1/2
• Γmax: 510-5 ms-2
• [0.1·10-3; 10-1 ] Hz
• Γn: 2.0·10-12 ms-2 /Hz1/2
• Γmax: 610-6 ms-2
• [5·10-3; 10-1 ] Hz
• Γn: 2.0·10-12 ms-2 /Hz1/2
• Γmax: 610-6 ms-2
• [5·10-3; 10-1 ] Hz
altitude~500kmaltitude~500km
altitude~260km
g
Courtesy TAS-F
In line common acceleration external acceleration at CoG
In line differential acceleration Gravity Gradient measurement
transverse differential acceleration angular acceleration
GOCE Seminar, 10-11 Jan 2013, Onera :Analysis of the obtained performance
Today : 3971 days in orbit
10 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 201310
GOCE performance, Accelerometer performanceSee details presentation by Bruno Christophe
Measured Trace : ~ 24 mE/Hz1/2
Depends on : Accelerometer performance Calibration performance Attitude control performance Linearity
VXX, VYY, VZZ
Accelerometer PSD in 40-100 mHz
ASH3,6 : 6.7 10-12 m/s2/Hz1/2
ASH1,4 : 3.9 10-12 m/s2/Hz1/2
ASH2,5 : 3.1 10-12 m/s2/Hz1/2
Assuming : accelerometers, the only source of the EGG noise
MICROSCOPE Expected Performancesincluding environment stochastic variations:• inertial pointing : 3.74 - 4.9 10-12 ms-2Hz1/2 @ forb=fep
• rotating pointing : 1.55 – 2.03 10-12 ms-2Hz1/2 @ fep
GOCE MICROSCOPE Gold wire : Ø= 5 m Ø=7.5 m PT-Rh Proof mass : m= 320g m=400 - 307 g Gap Y,Z : e = 299 m e= 600 m PM Polarisation : Vp = 7.5 V Vp =5 V Detection : Vd = 7.6 V @ 100 KHz Vd = 7.07 V @ 100 KHz Detector gain 1.7 mV / nano-m 0.3 - 0.26 mV / nano-m Scale factor :
Science data 1. 10-7ms-2/V 1.8 - 2.1 10-7 ms-2/V DFACS data 17. 10-6 ms-2/V 0.7- 1.7 10-6 ms-2/V
Range ± 6.5 10-6 ms-2 ± 4.8 - 4.6 10-7 ms-2
Expected Res. < 2 10-12 ms-2 Hz-1/2 < 2 10-12 ms-2 Hz-1/2
J Geod (2011) 85:759–775DOI 10.1007/s00190-011-0497-4
11 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
GOCE experience returnsee for details presentation by B. Christophe and B. Foulon
• Drag compensation • Attitude control• Alignments & scale factor matching• Non linearities
R. Rummel et al. J Geod (2011) 85:777–790
Björn Frommknecht et al. J Geod (2011) 85:759–775
Björn Frommknecht et al. J Geod (2011) 85:759–775
R. Floberghagen et al. J Geod (2011) 85:749–758
12 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 201312
MICROSCOPE : A dedicated instrument
One differential accelerometer = 2 inertial sensors Each inertial sensors exploits electrostatic Concept & Technology similar to GOCE•6 servo-channels and associated electrode sets sensing and actuations•Very steady and accurate configuration•Cylindrical configurationconcentric massesoverlapping electrodes along X linearity
Spin ElectrodesSpin Electrodes
Radial ElectrodesRadial Electrodes
Axial ElectrodesAxial Electrodes
Digital
Pos Det ADC ControlLaws
DACDVA
Drag Free Control
Science Data
PM
--
DVA (-) DAC
ADC
12
g
13 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Precise test-mass servo positioning thanks to• accurate machining• accurate metrology and integration• low noise electronics• thermal stability
XY
Y1+Y1- Y2
+Y2-
Z1+
Z1-Z2+
Z2-X
Z
Payload 35 kg, 40 Watts : 2 similar instruments, each including one pair of masses : 2 pairs of masses : Pt / Pt & Pt / Ti Double difference of four inertial sensor outputs Scientific data & AOCS data for pointing and continuous drag compensation
Test-Masses
Silica cylinders for electrodes set
Vacuum system
Blocking system
Circuit boards for coax. connections
Hermetic connectors
Base plate assembly for high accurate positioning
24 bars chamber
Electro-valves
MICROSCOPE instrument configuration see for details presentation by Manuel Rodrigues
14 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Geometrical AccuracyThermal Stability and Weak AgingConductivityIntegrationOff gassing- Out gassingVibration Resistance
SENSOR UNITsee for details presentation by Vincent Lebat
15 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
T-SAGE Payload Configurationsee for details presentation by Damien Boulanger
Mecanical sensor core :2 Differential accelerometers
mounted on 1 reference plateeach one contains 2 coaxial inertial sensorsno electronics, only wiring
weak power dissipation
Front End Electronics :•2 FEEU Units, one per accelerometer including:
Low noise analogue electronicsAnalogue to Digital ConversionDigital to Analogue Conversion
Interface Control Units : •1 Unit stacking 2 ICU (1 for each FEEU) with independent electrical functions: Digital control laws & Interfaces with the Satellite buses
OBCPCDU
0.3 K/Hz1/2
1mK @ fep
3.0 K/Hz1/2
5mK @ fep
± 4 °C
16 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
INSTRUMENT QUALIFICATION : achieved in 2012see for details presentation by Hans Selig and Françoise Liorzou
Verification of the operation in free fall tests with dedicated electronics :• mass levitation & servo-loops dynamics• bias levels• electrical interfaces between Sensor & sensitive electronics units• resistance to launch vibrations & thermal cycling• resistance to pyro chocks
Free-Fall in ZARM Bremen Tower
Chocks
Vibrations
Thermal cycling
17 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
MICROSCOPE Satellitesee for details presentation by Alain Robert, Michel Bach
2 differential accelerometers in thermal cocoon
2 differential accelerometers in magnetic cocoon
payload at the center of the satellite :-for thermal stability-for spin mode-for self gravity
X
Z Y
payload and star sensor for attitude control
18 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
MICROSCOPE Satellitesee for details presentation by Michel Bach
2 differential accelerometers in thermal cocoon
2 differential accelerometers in magnetic cocoon
payload at the center of the satellite :-for thermal stability-for spin mode-for self gravity
X
Z Y
payload an star sensor for attitude control
19 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Drag free and Sensor control loops : Principlesee for details presentation by Pascal Prieur
~ a few Hz
ProofMass
Inertial Sensor
SatelliteThrusters
ThrusterActuators
[f1 – f2 Hz]
Capacitive positionsensors
Electrostaticactuators
PID
Estimators & Control Laws
Inertial sensor control loop
Drag compensation& attitude control loops
ADC+ PID
DAC
electrostatic loops
Instrument operation and reduction of perturbationsMass Off-Centering & Earth Gravity Gradient
Eccentricity < 5.10-3
+ S/C position tracking (Doppler) & GPS + Pointing, 10-3 rad with variations
Mass Off-Centering & Satellite Attitude Control Angular velocity variations Angular accelerations variations
Sensitivity Matching & linearity Drag-Free Control
Instrument calibration
20 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
EP Test Performance evaluationsee presentation by Ratana Chhun, Gilles Métris
Electronics: Verified on FM - Sensor accuracy and integration verified on QM Drop tower tests Demonstration of control laws operation & automatic acquisition before & after vibrations Expected Performance: better than 10-15
2 operating Satellite Modes :Rotating & Inertial modes fep
different kinetic conditions different thermal conditions Instrument
Performance evaluation from :Instrument error budgetSatellite drag compensation & attitude control performanceCalibration performanceEarth gravity gradient correction accuracy
Budget sub divided into more than 100 contributorsMission : More than 60 contributorsStochastic errors (colored noise) and systematic errors (tone errors at the frequency of the test)
Accuracy of the EP Test Specs of sensor unitelectronicsinstrument environmentmeasurement corrections Specs of satellite sub-systems
attitude & position recoveryin orbit calibration
Sensor Unit : •geometry•electrical & magnetic properties•thermal behavior•vacuumQM model performance
Analog electronics : gain, bandwidth, noise, linearity, thermal sensitivitiesDigital electronics :conversion accuracy, rate, computation accuracyFEEU FM model performanceICU EM model performance
Previous instruments performance & modelsSpecific experimental investigations
Equipment performancesAnalytical computationsSoftware Simulations
P.Touboul, 2009, Space Sci. Rev.
21 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
EP Test Performance validation see for details presentations by Ratana Chhun, Gilles Métris
2 operating Satellite Modes :Rotating & Inertial modes fep
different kinetic conditions different thermal conditions Instrument
DEMONSTRATION of Performance evaluation from :Instrument error budgetSatellite drag compensation & attitude control performanceCalibration performanceEarth gravity gradient correction accuracy
Accuracy of the EP Test Specs of sensor unitVALIDATION electronics
instrument environmentmeasurement corrections
Specs of satellite sub-systemsVALIDATION attitude & position recovery
in orbit calibration
Previous instruments performance & modelsSpecific experimental investigations
Equipment performances VALIDATIONAnalytical computationsSoftware Simulations
Sensor Unit : •geometry•electrical & magnetic properties•thermal behavior•vacuumFM model performance VALIDATION
Analog electronics : gain, bandwidth, noise, linearity, thermal sensitivitiesDigital electronics :conversion accuracy, rate, computation accuracyFEEU FM model performance VALIDATIONICU EM model performance VALIDATION
22 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
SPACE EXPERIMENT CONTROL & VALIDATIONsee for organization presentation by P.Y. GUIDOTTI
SATELLITE CONTROLCENTER
CNES Toulouse
SCIENTIFIC MISSIONCENTER
Onera Palaiseau
Satellite OperationPayload OperationMission Scenario ExecutionTM/TCExpertise
Payload SurveyData Quick-look SurveyMission Scenario Definition & UpdateExpertiseData processing, corrections & validationsData archivingData distributionsExperiment results & Phenomenology
Organization Rules and responsibilitiesInterfacesOperations & Software
23 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Thanks to MICROSCOPE present partners
Physikalisch-Technische
Bundesanstalt
Observatoire de la Côte d’Azur
1 10 4 1 10 3 0.011 10 18
1 10 17
1 10 16
1 10 15
1 10 14
1 10 13
1 10 12
1 10 11
1 10 10
Calibrated centringNon Calibrated1E-15 EP signal @ 730km
Hz
Diff
eren
tial A
ccele
ratio
n (m
/s²)
1 10 4 1 10 3 0.011 10 18
1 10 17
1 10 16
1 10 15
1 10 14
1 10 13
1 10 12
1 10 11
1 10 10
Calibrated centringNon Calibrated1E-15 EP signal @ 730km
Hz
Diff
eren
tial A
ccele
ratio
n (m
/s²)
24 Pierre Touboul, Mission Overview, MICROSCOPE Colloquium II, Palaiseau, 29-30 Jan. 2013
Thank you for your attentionQuestions ?