THEMIS ARTEMIS Constellation Status Plans for Future Manfred

THEMIS ARTEMIS Constellation Status, Plans for Future Manfred Bester University of California - Berkeley Post-Fall AGU SWT Meeting 1 Dec. 18, 2010

THEMIS Outline ARTEMIS Outline • • Mission Status Summary Mission Networks Flight Systems Performance Anomaly Status ARTEMIS P 1 Dynamics Anomaly Science Operations Metrics ARTEMIS Navigation Status Summary Post-Fall AGU SWT Meeting 2 Dec. 18, 2010

THEMIS Mission Status Summary ARTEMIS Constellation Status • All five probes are very healthy in general and continue to collect high quality science data after 3. 75 years of successful on-orbit operations • In general none of the five probes show any sign of degradation in any of the spacecraft subsystems • One spacecraft lost an EFI sensor sphere • Few other minor issues with no impact to mission success • Fuel reserves continue to allow for ambitious mission extensions Ground Systems & Operations Status • • • All ground systems are processing nominally Hardware, software and procedures are kept up to date Executed 430 individual thrust operations to date Completed more than 23, 000 passes to date (DSN: nearly 900) All routine passes supported in lights-out mode Post-Fall AGU SWT Meeting 3 Dec. 18, 2010

THEMIS Mission Networks ARTEMIS THEMIS Probes TDRS GDSCC DSS-15, 24, 27 CDSCC DSS-34, 45 MDSCC DSS-54, 65 BGS Secure Intranet AGO, MILA, WGS JPL DSN White Sands Complex USNHI, USNAU USN NMC GSFC GCC Open IONet T 1 Line Isolated Dial-up ISDN Line Berkeley Multi-mission Operations Center Post-Fall AGU SWT Meeting HBK 4 Dec. 18, 2010

THEMIS Spacecraft Bus Systems Status ARTEMIS Flight Systems Status Summary – Spacecraft Bus System Spacecraft Bus Subsystem Probe Bus Subsystems A-E Nominal BAU FSW A-E Nominal All probes are running BAU FSW version 0 x 3701; upload completed on Nov. 7, 2009 Telecom A-E Antennas weaker than expected Degraded operational link budgets (B: -3 d. B; A, C, D: -4 d. B; E: -5 d. B) Power A-E Nominal Power systems allow operation through 4 -h shadows; longest penumbra ~8 h Thermal A-E Nominal No issues in nominal mission attitude Thermal leak near Service Valve 2 Analysis shows no risk of freezing fuel lines E Status Comments RCS A-E Nominal All RCS thrusters & valves function well, no leaks ACS A-E Nominal All ACS sensors nominal Post-Fall AGU SWT Meeting 5 Dec. 18, 2010

THEMIS Instrument Status ARTEMIS Flight Systems Status Summary – Instruments System Subsystem Probe Status Comments Instrument Suite A-E Nominal IDPU FSW A-E Nominal All probes are running IDPU FSW version 0 x 56; upload completed on Nov. 19, 2010 EFI B Lost -X sensor sphere and part of the fine wire due to melting of the fine wire, likely as a result of micrometeorite impact, possibly from the Orionids (Oct. 14, 2010) Reconfigured instrument to use ±Y sensors to obtain spin-fit DC electric field measurements and to trigger bursts; ±X pair continues to provide wave measurements; no significant science loss ESA A-E Small degradation in sensitivity of electron sensor below 30 e. V in certain angle sectors Localized MCP degradation in angle sectors looking along the spin axis may be caused by emission of photo electrons from axial booms – probes A and B have least amount of degradation, had booms deployed later SST A–E Noticeable degradation of sensitivity in all ion detectors Caused by ion implantation; Increased sensor bias once to restore nominal sensitivity D Attenuator B stuck in closed position due to a failure of the actuator mechanism (April 9, 2010) While attenuator A is still functioning, both attenuators will likely be left in the closed position for the remainder of the mission; no significant science loss Post-Fall AGU SWT Meeting 6 Dec. 18, 2010

THEMIS ARTEMIS THB/P 1 Dynamics Anomaly Sequence of Events • On October 15, both GSFC/FDF and UCB/SSL observed an unexplained range and range rate bias in their OD solutions. Note the range rate bias of -5. 6 cm/s in the last two tracks (DS 45, BRKS)! This bias prevailed during subsequent tracks, i. e. the effect appeared to be real and suggested a ΔV event had occurred. Reference: P. Morinelli, NASA/GSFC/FDF Post-Fall AGU SWT Meeting 7 Dec. 18, 2010

THEMIS ARTEMIS Deployed Instruments THEMIS Probe with Deployed Instruments Preamplifier, fine wire and sphere sensor (−X) Electric Field Instrument (EFI): Spin plane booms (SPBs): X: ± 25 m end-to-end (1 -2) Y: ± 20 m end-to-end (3 -4) Axial booms (AXBs): (5 -6) Preliminary analysis indicates the EFI −X sphere actually departed from the spacecraft. Post-Fall AGU SWT Meeting 8 Dec. 18, 2010

THEMIS EFI Dimensions ARTEMIS 3. 5 m X: 24. 39 m Engineering unit of preamplifier, fine wire, sphere and key reel Post-Fall AGU SWT Meeting 9 Dec. 18, 2010

THEMIS Expected ∆V from Sphere Loss ARTEMIS Sun Sensor ∆Vspacecraft = 0. 056 m/s EFI Preamp −X Sphere ∆Vsphere = 51. 032 m/s ω = 2 π / 3. 0 s Spin plane boom length: 24. 39 m from s/c center to sphere, 21. 39 m from s/c center to preamp Note: This figure is not to scale. Post-Fall AGU SWT Meeting 10 Dec. 18, 2010

THEMIS Observed ∆V ARTEMIS Targeting Method ∆V [m/s] Azimuth [deg] Elevation [deg] Position only 0. 05654 79. 751 -0. 945 Velocity only 0. 06925 78. 338 31. 277 Position and Velocity 0. 05775 77. 379 0. 679 Elevation of the impulse should be near the spin plane, which may indicate the velocity-only targeting is an outlier. Analysis based on post-event orbit solution Reference: D. Folta, NASA/GSFC/NMDB Post-Fall AGU SWT Meeting 11 Dec. 18, 2010

THEMIS Thrust Maneuver Summary ARTEMIS Maneuver and Fuel Budget Summary to Date THEMIS A P 5 THEMIS B P 1* THEMIS C P 2* THEMIS D P 3 THEMIS E P 4 Initial Fuel Load [kg] 48. 800 48. 780 48. 810 48. 820 Expended Fuel [kg] 32. 486 39. 373 40. 240 22. 647 22. 467 Remaining Fuel [kg] 16. 314 9. 407 8. 570 26. 163 26. 353 Remaining Fuel [%] 33. 4 19. 3 17. 6 53. 6 54. 0 Total Expended ΔV [m/s] 654. 536 838. 075 849. 600 442. 761 430. 354 Parameter * ARTEMIS Probes Total executed thrust operations by end of prime mission: 296 Total executed thrust operations to date: 430 Post-Fall AGU SWT Meeting 12 Dec. 18, 2010

THEMIS ARTEMIS THD: Dec. 24 - 30, 2010 Post-Fall AGU SWT Meeting Geostationary Conjunctions THE: Feb. 25 - Mar. 5, 2011 13 THA: Apr. 27 - May 8, 2011 Dec. 18, 2010

THEMIS ARTEMIS Science Operations Metrics Science Instrument Commanding • • • Configuration changes discussed in weekly operations meetings All instruments command sequences typically tested on Flat. Sat prior to upload (Flat. Sat was moved from cleanroom to operations area) Operations team implemented 117 Instrument Configuration Change Requests (ICCRs) to date, based on input from the science team Science Data Recovery Metrics • • Data dumps near perigee typically at 128 K, 512 K or 1024 K Tohban monitors data quality and completeness Required data volumes: 591 -751 Mbits/orbit, varying with compression Actual recovered data volumes (mostly with >99% completeness): 2007: 453 – 486 Mbits/orbit 2008: 664 – 924 Mbits/orbit 2009: 837 – 1050 Mbits/orbit 2010: 907 – 919 Mbits/orbit (THEMIS-Low probes) Post-Fall AGU SWT Meeting 14 Dec. 18, 2010

THEMIS ARTEMIS Data Recovery Metrics Post-Fall AGU SWT Meeting 15 Dec. 18, 2010

THEMIS / ARTEMIS Trajectories on 21 -Sep-2009 ARTEMIS THEMIS B orbit after ORM 5 and first lunar approach: 347, 000 x 19, 300 km THEMIS C orbit after ORM 13 Post-Fall AGU SWT Meeting 16 16 Dec. 18, 2010

THEMIS B / ARTEMIS P 1 – First Lunar Approach ARTEMIS 17 -Sep-2009 THEMIS B orbit after ORM 5 and first lunar approach within 46, 000 km, causing orbit to increase to 347, 000 x 19, 300 km Moon Post-Fall AGU SWT Meeting 17 17 Dec. 18, 2010

THEMIS B / ARTEMIS P 1 – Second Lunar Approach ARTEMIS 02 -Dec-2009 Flyby Targeting Maneuver (FTM 2) near perigee of last equatorial orbit Contingency options for executing missed FTM 2 19 -Dec-2009 Trajectory Correction Maneuver (TCM 1) near end of first highinclination orbit 07/08 -Dec-2009 Moon Second lunar approach (the knee) within 18, 800 km, causing inclination change from 10 to 58 deg Post-Fall AGU SWT Meeting 18 18 Dec. 18, 2010

THEMIS B / ARTEMIS P 1 – First and Second Lunar Flyby ARTEMIS 13 -Feb-2010 31 -Jan-2010 Second lunar flyby within 5, 000 km, resulting in trans -lunar trajectory First lunar flyby within 14, 300 km, resulting in back flip Moon The knee 08 -Dec-2009 − 31 -Jan-2010 Back flip 5 high-inclination orbits with 11 -day periods Post-Fall AGU SWT Meeting 19 19 Dec. 18, 2010

THEMIS B / ARTEMIS P 1 – Largest Range from Earth ARTEMIS 13 -Feb-2010 - 23 -Aug-2010 Weak stability boundary trajectory with two large excursions and one Earth flyby in between 06 -Jun-2010 Largest range from Earth: 1, 500, 000 km Post-Fall AGU SWT Meeting 20 20 Dec. 18, 2010

THEMIS B / ARTEMIS P 1 – Libration Orbit Insertion ARTEMIS 23 -Aug-2010 Libration orbit insertion (LL 2) Post-Fall AGU SWT Meeting 21 21 Dec. 18, 2010

THEMIS B / ARTEMIS P 1 Orbit Evolution ARTEMIS Post-Fall AGU SWT Meeting 22 22 Dec. 18, 2010

THEMIS C / ARTEMIS P 2 – Final Earth Orbits THEMIS ARTEMIS Moon Lunar orbit 27 -Feb-2010 26 -Mar-2010 28 -Mar-2010 Shadow deflection Trajectory correction maneuver (SDM 1) maneuver (TCM 1) Lunar flyby within 10, 200 km of center, resulting in translunar trajectory 24 -Mar-2010 Flyby targeting maneuver (FTM 1) 26 -Feb-2010 Last orbit raise maneuver (ORM 27) 15 -Mar-2010 Shadow deflection maneuver (SDM 2) 22 -Mar-2010 Long partial Earth shadow Post-Fall AGU SWT Meeting 23 23 Dec. 18, 2010

THEMIS ARTEMIS THEMIS C / ARTEMIS P 2 Orbit Evolution Post-Fall AGU SWT Meeting 24 24 Dec. 18, 2010

THEMIS B & C / ARTEMIS P 1 & P 2 – Libration Orbits ARTEMIS Libration orbit (LL 1) Moon Libration orbit (LL 2) Post-Fall AGU SWT Meeting 25 25 Dec. 18, 2010

THEMIS B / ARTEMIS P 1 Libration Orbits – Moon Centered Coordinates Credit: NASA/GSFC ARTEMIS Post-Fall AGU SWT Meeting 26 26 Dec. 18, 2010

THEMIS Summary ARTEMIS Summary • Overall Mission Status – – • Flight Systems – – • All bus flight subsystems continued to perform very well All science instruments are working very well in general Ground Systems – – • Completed THEMIS prime mission on November 19, 2009 Encountered 50 anomalies since launch - 39 closed None of the anomalies caused a serious risk to mission success Operations team staffing adequate for THEMIS & ARTEMIS support All ground systems continue to function well Software tools are continually refined and extended as required ARTEMIS Mission Extension – – – Initiated Earth departure on July 20, 2009 Lissajous science phase started on October 22, 2010 Lunar orbit insertion likely delayed until July 2011 (details are TBD) P 1 to date: 5 ORMs, 2 FTMs, 8 TCMs, 1 DSM, 13 SKMs P 2 to date: 27 ORMs, 1 FTM, 2 SDMs, 5 TCMs, 3 DSMs, 8 SKMs Post-Fall AGU SWT Meeting 27 Dec. 18, 2010