1 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Agenda ðSystem progress report §Scenario of observations §Satellite engineering Confirmation of the flight domain §System engineering Satellite-to-ground link Telemetry budget §Launch of COROT Picture of SOYUZ in Kourou

2 COROT Science Week, Marseille, 3-6 June 2003 Instrument progress report COROTCASE COROTEL COROTLOG COROTCAM PROTEUS

3 COROT Science Week, Marseille, 3-6 June 2003 System progress report Satellite engineering overview ðMany activities §Spacecraft mathematical model for coupled load analysis with the launcher §SED-16 star tracker accommodation §AOCS specific command & control §Mechanical and electrical interfaces ðAOCS performances §To be estimated after coupled simulation with payload ecartometry §Results available for the next Corotweek (Marseille, spring 2003) ðSpacecraft roll domain §Power budget improved by Li-Ion battery §Beginning of life : simulations show that the ± 20° requirement will be met §End of Life (low electrical efficiency, broken cells) : performance TBC ðLast step of the contract negotiation with Alcatel §Contract to be signed in the first quarter of 2003

4 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Orbit parameters ðThe orbit will not be kept phased after commissioning §risk of sun glare in case of semi-major axis correction maneuver §semi-major axis drift over 5 years : - 7 km (atmospheric drag) §orbit period stability over 6 months : better than 1 s Eclipse Xs+ Thruster along Xs Sun direction

5 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Orientation of the satellite - flight domain Sun

6 COROT Science Week, Marseille, 3-6 June 2003 COROT mission The sky observed by COROT

7 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Satellite design / axes Zs+ Xs+ Ys+ Equipment bay Upper compartment with sensitive equipment Fine thermal regulation subsystem

8 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Platform design ð“PROTEUS Evolution” family §series of 5 platforms §upgraded electrical and AOCS chains ðLi-Ion battery §higher capacity (80 A h) no more problem of power supply in Safe Hold Mode §lower thermal dissipation the battery sidewall can withstand any solar incidence no need to rotate on the boresight axis after 5 months ðNew Magneto Torquer Bars §higher capacity (180 A m 2 ) better convergence of the Safe Hold Mode §equipment driven by a proportional control law no more pointing disturbances due to MTB activations ðOther features : new star trackers (SODERN), 2-antenna GPS

9 COROT Science Week, Marseille, 3-6 June 2003 COROT mission New mission schedule ðThermal constraints shrunk to payload constraints §the Ys+ satellite wall (focal unit radiator) must be in the shade as much as possible ðNo more 180° rotation on Xs between CP and EP ðNo more EP2 critical thermal configuration for payload design ðSeveral possibilities for the scheduling §Exploratory Programs can be carried out either at the beginning or at the end of a 6-month period §an alternate schedule CP1, EP1, CP2, EP2 is operationally recommended ðFocal unit radiator temperature worst cases in 1b and 2b §1b and 2b zones crossed by the Line of Equinoxes §temperature depending on direction of observation and roll angle

10 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Straylight Thermal constraints ðpolar caps ðlightened under small angles ðsee the Corotweek n°3 (Liège) - presentation by Annie Baglin « scattered light from Earth » §the maximum is reached when the satellite flies over the day part of the Earth

11 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Eclipses (over the year) ðmax : 0.34 T orb

12 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Previous schedule “Peace and Love” Line of nodes Summer Winter Autumn Solar declination up to +23° Ys+ Solar declination down to –23° Central Program 2 Exploratory Programs 1 & 2 180° rotation on Zs 180° rotation on Xs 180° rotation on Zs Satellite axes in a fixed orbital reference frame R OF X J2000 Y J2000 X OF Z OF Equatorial plane 12.5° Earth orbit Central Program 1 Line of Equinoxes Spring S Xs+ Zs- Xs+ Zs- Ys+ Xs+ Zs- Ys+ Zs- Xs+ Ys+ Anticenter (6h50)Center (18h50)

13 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Updated schedule “Piece of cake” Line of nodes Summer Winter Autumn Solar declination up to +23° Solar declination down to –23° Central Program 2 Exploratory Programs 1 & 2 180° rotation on Zs Satellite axes in a fixed orbital reference frame R OF X J2000 Y J2000 X OF Z OF Equatorial plane 12.5° Earth orbit Central Program 1 Line of Equinoxes Spring S Xs+ Zs- Ys+ Zs- Xs+ Ys+ 1b 1a2b 2a Center (18h50)Anticenter (6h50)

14 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Line of nodes Summer Autumn Solar declination up to +23° EP 1 180° rotation on Zs Satellite axes in a fixed orbital reference frame R OF X J2000 Y J2000 Equatorial plane 12.5° Earth orbit CP 1 Line of Equinoxes Spring Zs- Xs+ Ys+ 1b 1a 18h50 Favorable direction in the observation cone RA + S

15 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Line of nodes Winter Autumn Solar declination down to –23° CP 2 EP 2 180° rotation on Zs Satellite axes in a fixed orbital reference frame R OF X J2000 Y J2000 Equatorial plane 12.5° Earth orbit Line of Equinoxes Spring Xs+ Zs- Ys+ 2b 2a 6h50 Favorable direction in the observation cone RA + S

16 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Straylight ðmaximum level (on the orbit) as a function of time §case of winter -12° RA +12° RA -12° dec +12° dec

17 COROT Science Week, Marseille, 3-6 June 2003 COROT mission Performance management ðPerformance management consists in choosing the most favorable edge for each observing run §a slight drop in periodic performances (compatible with the requirements) can be tolerated for the EP observing runs §white noise b phot = f(1/  T obs ) in Fourier space  spectrum analysis less sensitive to periodic perturbations (hidden lines) in EP runs  i 2 Ai / (  b phot (T)) 1 / Qi < 100  Hz ðTo define a scenario, the users shall have a series of criteria §direction of observation §roll angle to optimize the projection of the targets onto the CCD §criticity of the thermal regulation (level, variability) function of the roll angle §criticity of the straylight intensity if any

18 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft overview Spacecraft overview (-Z s sidewall ) Antenne patch GPS -X s Antenne patch GPS -Zs ProteusCorotcase Corotel

19 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft overview Spacecraft overview (+Z s sidewall) Corotel Corotcase Proteus

20 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft overview Spacecraft overview (+Z s sidewall)

21 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft overview Ys+ Xs+ Zs+ S RSF cover dec < 0 Sidewall in the shade WINTER - Sun in the back of the satellite

22 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft overview Ys+ Xs+ Zs+ S RSF cover dec < 0 Sidewall lightened if roll < 0 WINTER - First days roll < 0

23 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft overview Ys+ Xs+ Zs+ S RSF cover dec > 0 Sidewall lightened even if roll = 0 increasing flux when roll > 0 WINTER - Last days (round J91) roll > 0

24 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft overview Spacecraft overview (+Z s sidewall)

25 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft overview ðEquipment bay (COROTCASE) §scientific data processing electronics BCC camera control BEX extraction units DPU processor §instrument housekeeping electronics BCV power distribution BS1 analogical payload telemetry BS2 synchronization and thermal regulation ðOn-board software (COROTLOG) §aperture photometry algorithms §angle error measurements for AOCS §satellite-to-ground link : 900 Mbits/jour

26 COROT Science Week, Marseille, 3-6 June 2003 System progress report Spacecraft roll domainwinter Ys+ Zs+ S E CP and EP n°2 Objective : ± 20° angle for optimum power budget :  = arctan (-tan  sin  ) = 5.25° Confirmed for Beginning of Life

27 COROT Science Week, Marseille, 3-6 June 2003 Spacecraft roll domain summer Ys+ Zs+ CP and EP n°1 E S Objective : ± 20° angle for optimum power budget :  = arctan (-tan  sin  ) = 5.25° System progress report Confirmed for Beginning of Life

28 COROT Science Week, Marseille, 3-6 June 2003 System progress report System engineering overview ðSystem engineering activity currently focused on §instrument modes and in-flight operations §all command & control interfaces §ground segment architecture §use of ground stations §system tools for Corotsky §light curve corrections §level 0/1 products CCC PLTM HKTM Network CMC TC TTCET CDC

29 COROT Science Week, Marseille, 3-6 June 2003 System progress report Instrument modes VEILLE SAFE OFF VALIDATION ECARTOMETRIE GROSSIERE VALIDATION ECARTOMETRIE FINE VALIDATION IMAGE EXOPLANETES VALIDATION IMAGE ASTERO VALIDATION PLAN DE MASQUES  OBSERVATION      Phase de Mise en station CALIBRATION PERIODIQUE Modes dédiés aux CALIBRATIONS DEBUT DE VIE

30 COROT Science Week, Marseille, 3-6 June 2003 System progress report Satellite-to-ground link capacity ðStation Acquisition Phase Preparation of an observing run (7 days) §VFA + NTL + KRN for many TC/TM operations §useful scientific telemetry up to 2.2 Gbits / day

31 COROT Science Week, Marseille, 3-6 June 2003 System progress report Satellite-to-ground link capacity ðObservation Phase Observing run (20, 150 days) §VFA + NTL §useful scientific telemetry up to 1.4 Gbits / day

32 COROT Science Week, Marseille, 3-6 June 2003 Satellite-to-ground link capacity ðThe nominal scientific mission is performed with VFA station §Seismology 12 windows by CCD –5 star windows, with 2 mask images (over 32 s) –5 background windows –2 offset windows §Exoplanets 6000 windows by CCD –4 964 chromatic star windows –36 oversampled chromatic star windows –949 monochromatic star windows –42 oversampled monochromatic windows (including offset) –9 imagettes §Total for 2 photometric chains : kbits / day System progress report

33 COROT Science Week, Marseille, 3-6 June 2003 System progress report Satellite-to-ground link capacity ðHow the additional telemetry with NTL station can be used ? §More seismology mask images 1 mask image over 32 s --> 45.6 Mbits / day 1 mask image over 16 s --> 91.6 Mbits / day 1 mask image over 8 s -->182.4 Mbits / day (mask size = 25 x 25) §More exoplanet imagettes 1 imagette over 32 s --> 6.5 Mbits / day ðExamples of scenario §Spreadsheet program §5 seismology mask images (over 32 s) + 25 exoplanet imagettes x 2 §3 seismology mask images (over 16 s) + 15 exoplanet imagettes x 2 §2 seimology mask images (over 8 s) + 20 exoplanet imagettes + 2 seismology mask images (over 32 s) + 20 exoplanet imagettes §Total for 2 photometric chains : < kbits / day

34 COROT Science Week, Marseille, 3-6 June 2003 Project status Launch of COROT in June 2006 ðLaunch of COROT by SOYUZ/ST from the Guiana Space Center §Choice made by CNES headquarters in July 2002 §Maiden flight from Kourou §Contract to be signed with Arianespace before end of 2003, after next ESA Council §Civil engineering in Malmanury River expected before July 2003 §If any inacceptable delay on the launch pad work, back-up by ROCKOT from Plesetsk

35 COROT Science Week, Marseille, 3-6 June 2003 System progress report