1. University of California - Berkeley
Constellation Status,
Plans for Future
Manfred Bester
University of California - Berkeley

2. 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

3. Prime Mission
Time History of Events and Macroscale Interactions during Substorms (THEMIS)
NASA Medium-class explorer mission Managed in PI Mode by UCLA/UCB
5 Probes in synchronized Earth orbits with periods of
4, 2 and 1 days
Conjunctions are formed in magnetospheric tail every 4 days

4. Successful Launch Campaign
Probe Release: L + 70 min
Responsibility for Constellation Operations Transitioned to MOC at UCB
Launch:
February 17, 2007

5. Prime Mission Status Summary
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

6. Constellation Status Page

7. Science Instrument Commanding
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: %
Recovered / required data volume: %
Tohban monitors data quality and completeness

8. Flight Systems Status Flight Systems Status System Subsystem Probe
Comments
Spacecraft Bus
Bus Subsystems
A - E
Nominal
BAU FSW
Occasional glitches in on-board spin rate calculation
New BAU FSW version 0x3500 currently tested on FlatSat, upload scheduled for early 2009
Telecom
Antennas weaker than expected
Degraded operational link budgets
(B: -3 dB; A,C,D: -4 dB; E: -5 dB)
Power
Power systems allow operation through 4-h shadows
Thermal
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
IDPU FSW
All probes run IDPU FSW version 0x50
ESA
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
Small degradation of sensitivity
Increased sensor bias once to restore nominal sensitivity

9. 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)

10. 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
Number of Passes in Arc 25 40 32
Pass Duration [min]
Typical Achieved Accuracy
< 50 m
< 5 mm/s
Number of Orbit Solutions as of 11/24/2008
328
344
342
326
330

11. Executed Maneuver Summary
Parameter
THEMIS A P5
THEMIS B
P1*
THEMIS C
P2*
THEMIS D P3
THEMIS E P4
Initial Fuel Load [kg]
48.800
48.780
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]
Attitude Precessions 20 21 9 11 10
Spin Rate Changes 16 17
ΔV Maneuvers 23 22 27 19
Total Executed Maneuvers 59 60 52 38 39
* ARTEMIS Probes
Total executed thrust operations: 248

12. P1 Large Plane Change Maneuver
ΔV: m/s
Fuel: 13.2 kg

13. P2 Large Plane Change Maneuver
ΔV: m/s
Fuel: 10.5 kg

14. P1 Planned Maneuvers 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 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 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
M05_T2
2009/062 16:37:09.413
6.428
0.263
Apogee km
M05_T2 Spin Control
Post M05_T2
0.040
0.002
M1A_D2
2009/130 06:43:43.412
2.567
0.105
Apogee km
M1A_D2 Attitude Change
2009/130 10:52:58.172
0.315
0.013
M1A_D2 Spin Control
Post M1A_D2
0.047
M03_D2
2009/158 14:33:14.154
3.444
0.141
Apogee km
M03_D2 Spin Control
Post M03_D2
0.073
0.003
Contingency
10.674
0.5
Total
19.298
1.291
* Spin target is ± rpm

15. P2 Planned Maneuvers 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 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 km
M04_T2 Spin Control
Post M04_T2
0.020
M05_T2
2009/062 19:23:31.781
2.468
0.110
Apogee km
M05_T2 Spin Control
Post M05_T2
M1A_D2
2009/128 07:33:27.684
4.581
0.205
Apogee 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
M03_D2
2009/156 15:24:45.789
4.634
0.207
Apogee km
M03_D2 Spin Control
Post M03_D2
Contingency
10.046
0.500
Total
27.473
1.278
* Spin target is ± rpm

16. P1 & P2 Remaining Fuel 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
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

17. 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

18. ARTEMIS Concept of Operations
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 formation
NOTES: 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.

19. Network Communications
THEMIS
Probes
TDRS
GDSCC DSS-24, 27
CDSCC DSS-34, 45
MDSCC DSS-54, 65
WS1, AGO, MILA, WGS
JPL DSN
BGS
Secure
Intranet
White Sands
Complex
USNHI, USNAU
USN NMC
GSFC NMC
Open IONet T1 Line
Isolated Dial-up ISDN Line
Berkeley Multi-mission Operations Center
THEMIS/ARTEMIS Network Links
HBK

20. Spacecraft Constraints
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

21. Thruster Firing Modes Thruster Firing Modes Maneuver Type
Thrusters Involved
Depiction of
Operational Mode
Purpose 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 T2
pulsed firing
Perigee or apogee change
with deployed EFI booms
Beta Thrust
A1 and A2 continuous firing alternating with
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

22. Roles and Responsibilities
ARTEMIS Navigation Team
Mission Design & Baseline Trajectories
JPL/GNC
Trajectory Verification & Validation
GSFC/FDAB
Navigation Plans & Error Analysis
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

23. Top Level Schedule

24. P1 Impulsive ORM Sequence
THEMIS D2

25. P1 Lunar Approaches

26. Navigation Work Flow Finite Trajectory Design JPL/NAV
Orbit Determination Predictive Ephemeris
GSFC/FDF
Maneuver Operations
UCB
Ephemeris Products
Telemetry Data
Initial Trajectory
Maneuver Planning
GSFC/FDAB
Maneuver Reconstruction
UCB
Trajectory Verification and Correction
GSFC/FDAB
GMAN/GMAT Config
Post Execution State
Validated Trajectory
Maneuver Verification
UCB
Orbit Determination Definitive Ephemeris
GSFC/FDF
Ephemeris Products
Thruster CMD Sheets
Acquisition Data
Planning Products
Maneuver Calibration
GSFC/FDAB & UCB

27. Near Term Plans Mid Term Plans Long Term Plans Summary
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

28. Going Back to the Moon Landing: July 20, 1969 40 Years Later … Launch: