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Post-Fall AGU SWT Meeting 1 Dec. 18, 2010
THEMIS
ARTEMIS
Constellation Status,Plans for Future
Manfred Bester
University of California - Berkeley
Post-Fall AGU SWT Meeting 2 Dec. 18, 2010
THEMIS
ARTEMIS Outline
Outline• Mission Status Summary• Mission Networks• Flight Systems Performance• Anomaly Status• ARTEMIS P1 Dynamics Anomaly• Science Operations Metrics• ARTEMIS Navigation Status• Summary
Post-Fall AGU SWT Meeting 3 Dec. 18, 2010
THEMIS
ARTEMIS Mission Status Summary
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 4 Dec. 18, 2010
THEMIS
ARTEMIS
Berkeley Multi-mission Operations Center
White SandsComplex
GSFC GCC
THEMISProbes
SecureIntranet
TDRS
Open IONet T1 Line
HBK
Isolated Dial-up ISDN Line
AGO, MILA, WGS
USNHI, USNAU
BGSJPL DSN
GDSCC DSS-15, 24, 27CDSCC DSS-34, 45MDSCC DSS-54, 65
USN NMC
Mission Networks
Post-Fall AGU SWT Meeting 5 Dec. 18, 2010
THEMIS
ARTEMIS Spacecraft Bus Systems Status
Flight Systems Status Summary – Spacecraft Bus
System Subsystem Probe Status CommentsSpacecraft Bus
Bus Subsystems A - E Nominal
BAU FSW A - E Nominal All probes are running BAU FSW version 0x3701; upload completed on Nov. 7, 2009
Telecom A - E Antennas weaker than expected
Degraded operational link budgets(B: -3 dB; A,C,D: -4 dB; E: -5 dB)
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
E Thermal leak near Service Valve 2
Analysis shows no risk of freezing fuel lines
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 6 Dec. 18, 2010
THEMIS
ARTEMIS Instrument Status
Flight Systems Status Summary – Instruments
System Subsystem Probe Status CommentsInstruments Instrument Suite A - E Nominal
IDPU FSW A - E Nominal All probes are running IDPU FSW version 0x56; 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 eV 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 7 Dec. 18, 2010
THEMIS
ARTEMIS
Sequence of Events• On October 15, both GSFC/FDF and UCB/SSL observed
an unexplained range and range rate bias in their OD solutions.
THB/P1 Dynamics Anomaly
Note the range rate bias of -5.6 cm/s in the last two tracks (DS45, 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 8 Dec. 18, 2010
THEMIS
ARTEMIS Deployed Instruments
THEMIS Probe with Deployed Instruments
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)
Preamplifier, fine wire and sphere sensor (−X)
Preliminary analysis indicates the EFI −X sphere actually departed from the spacecraft.
Post-Fall AGU SWT Meeting 9 Dec. 18, 2010
THEMIS
ARTEMIS EFI Dimensions
Engineering unit of preamplifier, fine wire, sphere and key reel
3.5 m
X: 24.39 m
Post-Fall AGU SWT Meeting 10 Dec. 18, 2010
THEMIS
ARTEMIS
∆Vsphere = 51.032 m/s
ω = 2 π / 3.0 s
Sun Sensor
Expected ∆V from Sphere Loss
∆Vspacecraft = 0.056 m/s EFI Preamp
−X Sphere
Note: This figure is not to scale.
Spin plane boom length: 24.39 m from s/c center to sphere, 21.39 m from s/c center to preamp
Post-Fall AGU SWT Meeting 11 Dec. 18, 2010
THEMIS
ARTEMIS Observed ∆V
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
Reference: D. Folta, NASA/GSFC/NMDB
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
Post-Fall AGU SWT Meeting 12 Dec. 18, 2010
THEMIS
ARTEMIS Thrust Maneuver Summary
* ARTEMIS Probes
Maneuver and Fuel Budget Summary to Date
ParameterTHEMIS A
P5THEMIS B
P1*THEMIS C
P2*THEMIS D
P3THEMIS E
P4
Initial Fuel Load [kg] 48.800 48.780 48.810 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
Total executed thrust operations by end of prime mission: 296Total executed thrust operations to date: 430
Post-Fall AGU SWT Meeting 13 Dec. 18, 2010
THEMIS
ARTEMIS Geostationary Conjunctions
THD: Dec. 24 - 30, 2010 THE: Feb. 25 - Mar. 5, 2011 THA: Apr. 27 - May 8, 2011
Post-Fall AGU SWT Meeting 14 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 FlatSat prior to
upload (FlatSat 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 128K, 512K or 1024K• 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/orbit2008: 664 – 924 Mbits/orbit2009: 837 – 1050 Mbits/orbit2010: 907 – 919 Mbits/orbit (THEMIS-Low
probes)
Post-Fall AGU SWT Meeting 15 Dec. 18, 2010
THEMIS
ARTEMIS ARTEMIS Data Recovery Metrics
Post-Fall AGU SWT Meeting 16 Dec. 18, 2010
THEMIS
ARTEMIS
THEMIS / ARTEMIS Trajectories on 21-Sep-2009
THEMIS C orbit after ORM 13
THEMIS B orbit after ORM 5 and first lunar approach:347,000 x 19,300 km
16
Post-Fall AGU SWT Meeting 17 Dec. 18, 2010
THEMIS
ARTEMIS
THEMIS B / ARTEMIS P1 – First Lunar Approach
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
17
Post-Fall AGU SWT Meeting 18 Dec. 18, 2010
THEMIS
ARTEMIS
THEMIS B / ARTEMIS P1 – Second Lunar Approach
18
07/08-Dec-2009
Second lunar approach (the knee) within 18,800 km, causing inclination change from 10 to 58 deg
02-Dec-2009
Flyby Targeting Maneuver (FTM 2) near perigee of last equatorial orbit
02-Dec-2009
Contingency options for executing missed FTM 2
Moon
19-Dec-2009
Trajectory Correction Maneuver (TCM 1) near end of first high-inclination orbit
Post-Fall AGU SWT Meeting 19 Dec. 18, 2010
THEMIS
ARTEMIS
THEMIS B / ARTEMIS P1 – First and Second Lunar Flyby
19
13-Feb-2010
Second lunar flyby within 5,000 km, resulting in trans-lunar trajectory
31-Jan-2010
First lunar flyby within 14,300 km, resulting in back flip
Back flip
The kneeMoon
08-Dec-2009 − 31-Jan-2010
5 high-inclination orbits with 11-day periods
Post-Fall AGU SWT Meeting 20 Dec. 18, 2010
THEMIS
ARTEMIS
THEMIS B / ARTEMIS P1 – Largest Range from Earth
20
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 21 Dec. 18, 2010
THEMIS
ARTEMIS
THEMIS B / ARTEMIS P1 – Libration Orbit Insertion
21
23-Aug-2010
Libration orbit insertion (LL2)
Post-Fall AGU SWT Meeting 22 Dec. 18, 2010
THEMIS
ARTEMIS
22
THEMIS B / ARTEMIS P1 Orbit Evolution
Post-Fall AGU SWT Meeting 23 Dec. 18, 2010
THEMIS
ARTEMIS
23
THEMIS C / ARTEMIS P2 – Final Earth Orbits
24-Mar-2010
Flyby targeting maneuver (FTM 1)
22-Mar-2010
Long partial Earth shadow
Lunar orbit
28-Mar-2010
Lunar flyby within10,200 km of center, resulting in trans-lunar trajectory
15-Mar-2010
Shadow deflection maneuver (SDM 2)
27-Feb-2010
Shadow deflection maneuver (SDM 1)
26-Feb-2010
Last orbit raise maneuver (ORM 27)
Moon
26-Mar-2010
Trajectory correction maneuver (TCM 1)
Post-Fall AGU SWT Meeting 24 Dec. 18, 2010
THEMIS
ARTEMIS
24
THEMIS C / ARTEMIS P2 Orbit Evolution
Post-Fall AGU SWT Meeting 25 Dec. 18, 2010
THEMIS
ARTEMIS
THEMIS B & C / ARTEMIS P1 & P2 – Libration Orbits
25
Libration orbit (LL2)
Libration orbit (LL1)
Moon
Post-Fall AGU SWT Meeting 26 Dec. 18, 2010
THEMIS
ARTEMIS
26
THEMIS B / ARTEMIS P1 Libration Orbits – Moon Centered CoordinatesCredit: NASA/GSFC
Post-Fall AGU SWT Meeting 27 Dec. 18, 2010
THEMIS
ARTEMIS
Summary• Overall Mission Status
– 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
• Flight Systems– All bus flight subsystems continued to perform very well– All science instruments are working very well in general
• Ground Systems– 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)– P1 to date: 5 ORMs, 2 FTMs, 8 TCMs, 1 DSM, 13 SKMs– P2 to date: 27 ORMs, 1 FTM, 2 SDMs, 5 TCMs, 3 DSMs, 8 SKMs
Summary
