Constellation Status, Plans for Future Manfred Bester University of California - Berkeley
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Post-Fall AGU SWT Meeting 1 UCB/SSL – Dec. 20, 2008 THEMIS ARTEMIS Constellation Status, Plans for Future Manfred Bester University of California - Berkeley
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Constellation Status, Plans for Future Manfred Bester University of California - Berkeley. Overview. Overview Prime Mission Constellation Status Science Operations Maneuver Summary Fuel Budget Extended Mission ARTEMIS Concept of Operations Top Level Schedule Network Communications - PowerPoint PPT Presentation
Transcript of Constellation Status, Plans for Future Manfred Bester University of California - Berkeley
Post-Fall AGU SWT Meeting 1 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS
Constellation Status,Plans for Future
Manfred Bester
University of California - Berkeley
Post-Fall AGU SWT Meeting 2 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Overview
Overview• Prime Mission• Constellation Status• Science Operations• Maneuver Summary• Fuel Budget• Extended Mission• ARTEMIS Concept of Operations• Top Level Schedule• Network Communications• Roles and Responsibilities• Navigation Plans• Summary of Future Plans
Post-Fall AGU SWT Meeting 3 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Prime Mission
5 Probes in synchronized Earth orbits with periods of 4, 2 and 1 days
Conjunctions are formed in magnetospheric tail every 4 days
Time History of Events and Macroscale Interactions during Substorms (THEMIS)
NASA Medium-class explorer mission Managed in PI Mode by UCLA/UCBhttp://themis.ssl.berkeley.eduhttp://www.nasa.gov/themis
Post-Fall AGU SWT Meeting 4 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Successful Launch Campaign
Launch:February 17, 2007
Probe Release: L + 70 min
Responsibility for Constellation Operations Transitioned to MOC at UCB
Post-Fall AGU SWT Meeting 5 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Prime Mission Status Summary
• Prime Mission Status• Completed LEOP, coast phase, tail 1 and dayside 1• Upcoming tail 2 and dayside 2 seasons• Answered primary scientific questions already
• Constellation Status• All probes very healthy and collecting science data• Fuel reserves allow for ambitious mission extension
• Ground Systems & Operations Status• All ground systems processing nominally• Executed 248 individual thrust operations to date• Completed 10,000 passes on December 3, 2008• All routine passes supported in lights-out mode
Post-Fall AGU SWT Meeting 6 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Constellation Status Page
Post-Fall AGU SWT Meeting 7 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Science Operations
• Science Instrument Commanding• Configuration changes discussed in ops meetings• All instruments command sequences typically tested
on FlatSat prior to upload• Ops team implemented 75 ICCRs to date
• Science Data Recovery Metrics• Data dumps near perigee at 512K or 1024K• Outer probes get two passes whenever possible• Recovered / acquired data volume: 98 - 99% • Recovered / required data volume: 111 - 147%• Tohban monitors data quality and completeness
Post-Fall AGU SWT Meeting 8 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Flight Systems Status
Flight Systems StatusSystem Subsystem Probe Status Comments
Spacecraft Bus
Bus Subsystems A - E Nominal
BAU FSW A - E Occasional glitches in on-board spin rate calculation
New BAU FSW version 0x3500 currently tested on FlatSat, upload scheduled for early 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
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
Thermistor on Solar Array 3 has open circuit in shadow
Thermistors on SA 1,2,4 provide redundant information
Instruments Instrument Suite A - E Nominal
IDPU FSW A - E Nominal All probes run IDPU FSW version 0x50
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 Small degradation of sensitivity
Increased sensor bias once to restore nominal sensitivity
Post-Fall AGU SWT Meeting 9 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Anomaly Tracking
• Anomaly Tracking & Resolution• Tiger Team assigned for each flight system or major
ground system anomaly• Investigate and determine cause of anomaly• Recommend solutions, work-arounds and/or
mitigations• Provide final report
• Anomaly Tracking List• Items closed out when anomaly report released and
recommended actions were performed• Currently tracking 29 items (20 closed)
Post-Fall AGU SWT Meeting 10 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS THEMIS Orbit Determination
• Orbit determination (OD) for the THEMIS constellation is based on two-way Doppler tracking data and the Goddard Trajectory Determination System (GTDS).
• Tests are underway to characterize the THEMIS ranging capabilities for use during ARTEMIS.
Parameter THEMIS A/P5
THEMIS B/P1 THEMIS C/P2 THEMIS D/P3
THEMIS E/P4
Arc Length [d] 7 12 9 7 7
Number of Passes in Arc
25 40 32 25 25
Pass Duration [min] 20 - 30 20 - 30 20 - 30 20 - 30 20 - 30
Typical Achieved Accuracy
< 50 m
< 5 mm/s
< 50 m
< 5 mm/s
< 50 m
< 5 mm/s
< 50 m
< 5 mm/s
< 50 m
< 5 mm/s
Number of Orbit Solutions as of 11/24/2008
328 344 342 326 330
Post-Fall AGU SWT Meeting 11 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Executed Maneuver Summary
* ARTEMIS Probes
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] 23.412 33.508 27.029 20.208 19.944
Remaining Fuel [kg] 25.388 15.272 21.781 28.602 28.876
Total Expended ΔV [m/s]
452.600 694.618 537.979 390.927 377.661
Attitude Precessions 20 21 9 11 10
Spin Rate Changes 16 17 16 10 10
ΔV Maneuvers 23 22 27 17 19
Total Executed Maneuvers
59 60 52 38 39
Total executed thrust operations: 248
Post-Fall AGU SWT Meeting 12 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS P1 Large Plane Change Maneuver
ΔV: 296.5 m/sFuel: 13.2 kg
Post-Fall AGU SWT Meeting 13 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS P2 Large Plane Change Maneuver
ΔV: 227.7 m/sFuel: 10.5 kg
Post-Fall AGU SWT Meeting 14 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS P1 Planned Maneuvers
* Spin target is 20.2105 ± 0.0130 rpm
THEMIS B/P1 Time (UTC) ΔV [m/s] Fuel Used [kg] Purpose
M03_T2 2008/347 23:58:04.658 1.417 0.058 Apogee - 1463 km
M03_T2 Spin Control Post M03_T2 0.020 0.001 Spin Control*
M04_T2 2009/017 05:50:00.028 4.581 0.188 Apogee - 4721 km
M04_T2 Attitude Change 2009/017 10:06:26.055 0.333 0.014 Attitude Change to Nominal
M04_T2 Spin Control Post M04_T2 0.033 0.001 Spin Control*
M05_T2 2009/062 16:37:09.413 6.428 0.263 Apogee + 6388 km
M05_T2 Spin Control Post M05_T2 0.040 0.002 Spin Control*
M1A_D2 2009/130 06:43:43.412 2.567 0.105 Apogee + 2494 km
M1A_D2 Attitude Change 2009/130 10:52:58.172 0.315 0.013 Attitude Change to Nominal
M1A_D2 Spin Control Post M1A_D2 0.047 0.002 Spin Control*
M03_D2 2009/158 14:33:14.154 3.444 0.141 Apogee - 3392 km
M03_D2 Spin Control Post M03_D2 0.073 0.003 Spin Control*
Contingency 10.674 0.5
Total 19.298 1.291
Post-Fall AGU SWT Meeting 15 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS P2 Planned Maneuvers
* Spin target is 20.2105 ± 0.0130 rpm
THEMIS C/P2 Time (UTC) ΔV [m/s] Fuel Used [kg] Purpose
M03_T2 2008/346 01:30:27.968 3.664 0.164 Apogee +1384 km
M03_T2 Spin Control Post M03_T2 0.033 0.001 Spin Control*
M04_T2 2009/015 16:05:40.741 1.641 0.074 Apogee - 644 km
M04_T2 Spin Control Post M04_T2 0.020 0.001 Spin Control*
M05_T2 2009/062 19:23:31.781 2.468 0.110 Apogee + 957 km
M05_T2 Spin Control Post M05_T2 0.033 0.001 Spin Control*
M1A_D2 2009/128 07:33:27.684 4.581 0.205 Apogee + 1730 km
M1A_D2 Attitude Change 2009/128 11:43:39.382 0.247 0.011 Attitude Change to Nominal
M1A_D2 Spin Control Post M1A_D2 0.053 0.002 Spin Control*
M03_D2 2009/156 15:24:45.789 4.634 0.207 Apogee - 1761 km
M03_D2 Spin Control Post M03_D2 0.053 0.002 Spin Control*
Contingency 10.046 0.500
Total 27.473 1.278
Post-Fall AGU SWT Meeting 16 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS P1 & P2 Remaining Fuel
THEMIS C/P2 Remaining ΔV [m/s] Remaining Fuel [kg]
End of THEMIS D2 468.1 20.5
ARTEMIS ACS / Contingency 20.2 1.0
Net Remaining 447.9 19.5
THEMIS B/P1 Remaining ΔV [m/s] Remaining Fuel [kg]
End of THEMIS D2 326.0 14.0
ARTEMIS ACS / Contingency 21.5 1.0
Net Remaining 304.5 13.0
Post-Fall AGU SWT Meeting 17 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Extended Mission
Time History of Events and Macroscale Interactions during Substorms (THEMIS)3 Probes (A/P5, D/P3, E/P4) in synchronized Earth orbits with 1-day periods
Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun (ARTEMIS)2 Probes (B/P1, C/P2) in lunar orbits
Post-Fall AGU SWT Meeting 18 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS ARTEMIS ConOps
• ARTEMIS Concept of Operations• Transfer of outer two probes (B/P1 and C/P2) into
lunar orbits via Weak Stability Boundary trajectory using Earth and lunar gravity assist
• Communications with these two probes via DSN• Data recovery from lunar distances up to 128K• Attitude determination with sun sensor data only• No required flight software changes
• THEMIS Concept of Operations• THEMIS mission continues with inner three probes
(A/P5, D/P3, E/P4) in tighter formationNOTES: For all operational purposes all five probes shall continue to be referred to as THEMIS A-E.
New capabilities at the MOC shall be considered an upgrade, not a transition.
Post-Fall AGU SWT Meeting 19 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS
Berkeley Multi-mission Operations Center
White SandsComplex
GSFC NMC
THEMISProbes
SecureIntranet
TDRS
Open IONet T1 Line
HBK
Isolated Dial-up ISDN Line
WS1, AGO, MILA, WGS
THEMIS/ARTEMIS Network Links
USNHI, USNAU
BGS JPL DSN
GDSCC DSS-24, 27CDSCC DSS-34, 45MDSCC DSS-54, 65
USN NMC
Network Communications
Post-Fall AGU SWT Meeting 20 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS
Spacecraft Constraints Impacting ARTEMIS Operations
Constraint Operational Impact / Risks Work-around / Mitigation
Thruster locations on spacecraft
Thrust direction only in one hemisphere Insert bias maneuvers into navigation plan
No thrust operations in shadow due to RCS design
Cannot execute maneuvers in Earth or lunar shadows
Shift maneuvers outside of shadows
Survival of long shadows Spacecraft designed for maximum shadow duration of 180 min. Power systems performance allows shadows up to 240 min duration.
Design trajectory to avoid shadows longer than 240 min
EIRP of spacecraft transmitter with omni antenna
Spacecraft telecomm subsystem designed to work with 11-m class ground stations
Utilize DSN 34-m antennas and adjust telemetry rates to close link with positive margin, based on range and spacecraft attitude
Available sensor data for attitude determination
ACS and ADS designed to work with sun sensor and FGM data, requiring Earth’s magnetic field
Implement ADS based only on sun sensor data
Spacecraft Constraints
Post-Fall AGU SWT Meeting 21 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS
Thruster Firing Modes
Maneuver Type
Thrusters InvolvedDepiction of
Operational ModePurpose of Maneuver
Axial Thrust A1 and A2 continuous firing
Perigee or apogee change or combined in-plane and out-of-plane orbit change with stowed EFI booms
Side Thrust T1 and T2pulsed firing
Perigee or apogee changewith deployed EFI booms
Beta Thrust A1 and A2 continuous firing alternating withT1 and T2 pulsed firing
In-plane and out-of-plane orbit change with deployed EFI booms
Attitude Precession
A1 or A2 pulsed firing Attitude change
Spin-up / Spin-down
T1 or T2 continuous or pulsed firing
Spin rate adjustment
Thruster Firing Modes
Post-Fall AGU SWT Meeting 22 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Roles and Responsibilities
• ARTEMIS Navigation Team• Mission Design & Baseline Trajectories
• JPL/GNC
• Trajectory Verification & Validation• GSFC/FDAB
• Navigation Plans & Error Analysis• GSFC/FDAB
• Maneuver Targeting & Operations• GSFC/FDAB & UCB/SSL
• Orbit Determination & Error Analysis• GSFC/FDF & UCB/SSL
• Attitude Determination• UBC/SSL with software provided by GSFC/FDAB and a.i. solutions
Post-Fall AGU SWT Meeting 23 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMISTop Level Schedule
Post-Fall AGU SWT Meeting 24 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS P1 Impulsive ORM Sequence
ORM 1
ORM 8
THEMIS D2
Post-Fall AGU SWT Meeting 25 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS P1 Lunar Approaches
Post-Fall AGU SWT Meeting 26 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS
Thruster CMD SheetsAcquisition Data
Planning Products
Ephemeris Products
Orbit Determination Predictive Ephemeris
GSFC/FDF
Maneuver Verification
UCB
Finite Trajectory Design
JPL/NAV
Initial Trajectory
Trajectory Verification and
Correction
GSFC/FDAB
Validated Trajectory
Maneuver Planning
GSFC/FDAB
GMAN/GMAT Config
Telemetry Data
Maneuver Reconstruction
UCB
Post Execution State
Orbit Determination Definitive Ephemeris
GSFC/FDF
Maneuver Calibration
GSFC/FDAB & UCB
Ephemeris Products
Maneuver Operations
UCB
Navigation Work Flow
Post-Fall AGU SWT Meeting 27 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Summary
• Near Term Plans• Complete second tail season by April 2009• Outer probes maneuvered close to neutral sheet• Finalize ARTEMIS mission design
• Mid Term Plans• Complete second dayside season by July 2009• Start orbit raise maneuver sequence for P1 & P2
• Long Term Plans• Execute translunar trajectory phase for ARTEMIS
(P1 & P2)• Operate THEMIS (P3, P4, P5) in closer formation
Post-Fall AGU SWT Meeting 28 UCB/SSL – Dec. 20, 2008
THEMIS
ARTEMIS Going Back to the Moon
Launch:July 16, 1969
40 Years Later …
Landing:July 20, 1969
