Mission Operations Days: 2003/354 to 2003/360
December 20, 2003 00:00:00 GMT to December 26, 2003 00:00:00 GMT
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On December 22, 2003 (DOY 356), Terra spacecraft was returned to nominal status.
On December 24, 2003 (DOY 358), MODIS resumed Science operations.
(See below for details)
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Terra Spacecraft and MODIS Instrument Status:
| AM-1 "Terra" is in Normal Mode PFM MODIS is in A-Side Nominal Science Mode (Cross Strapped with FR B) |
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|---|---|---|
| Component | State(s) | Comment |
| Blackbody | A On (290K); B Off | Nominal Science Mode |
| Calibration Electronics | A On; B Off | Nominal Science Mode |
| Control Processor | A On; B Off | Nominal Science Mode |
| Nadir Door | Unlatched, Open | Nominal Science Mode |
| Space View Door | Unlatched, Open | Nominal Science Mode |
| Solar Diffuser Door | Unlatched, Screened | Permanent Configuration |
| FDDI Formatter | A On; B Off | Nominal Science Mode |
| FDDI Port | A On; B Off | Nominal Science Mode |
| FIFO Memory | #1 & #2 On; #3 & #4 Off | Nominal Science Mode |
| Format Processor | A Off; B On | Nominal Science Mode |
| Power Supplies | #1 On, #2 Off | Nominal Science Mode |
| PV VIS FPA | A On; B Off | Nominal Science Mode |
| PV NIR FPA | A On; B Off | Nominal Science Mode |
| PV SMIR FPA | A On; B Off | Nominal Science Mode |
| PV LWIR FPA | A On; B Off | Nominal Science Mode |
| PC LWIR FPA | A On; B Off | Nominal Science Mode |
| RC Outgas Heaters | All 3 (CS, IS, OS) Off | Nominal Science Mode |
| RC LWIR FPA Heater | On (83K) | Nominal Science Mode |
| RC SMIR FPA Heater | Off | Nominal Science Mode |
| Scan Assembly | A On; B Off | Nominal Science Mode |
| SDSM | Off | Nominal Science Mode |
| SRCA | Off | Nominal Science Mode |
| PS1 Survival Heater | Enabled | Nominal Science Mode |
| PS2 Survival Heater | Enabled | Nominal Science Mode |
| Timing Generator | A On; B Off | Nominal Science Mode |
| Flight Software | Rev BD + 11 sets of patches
|
Nominal Science Mode |
| Inhibit Ids Set | none | Nominal Science Mode |
| TMON 66 | Disabled | Nominal Science Mode |
| TMON 67 | Disabled | Nominal Science Mode |
| TMON 68 | Enabled | Nominal Science Mode |
| TMON 69 | Disabled | Nominal Science Mode |
This Week’s Completed MODIS Activities:
Saturday, December 20, 2003
None
Sunday, December 21, 2003
None
Monday, December 22, 2003
2003/356 21:43:10-21:44:29 Real-Time MOD_STBY_TXTN('A') Transitions MODIS from SAFE mode to STANDBY mode
2003/356 21:44:58-21:45:30 Real-Time MOD_MEM_DUMP('MOTOR_POS_WHEN_HIT',12,0,0,1,1) Dumps door motor position trigger when hit table
2003/356 21:46:10-21:49:07 Real-Time MOD_SVD_TO_OPEN Opens MODIS Space View Door
2003/356 21:49:15-21:49:48 Real-Time MOD_MEM_DUMP('MOTOR_POS_WHEN_HIT',12,0,0,1,1) Dumps door motor position trigger when hit table
2003/356 22:33:57-22:36:20 Real-Time MOD_SCI_TXTN('A') Transitions MODIS from STANDBY mode to SCIENCE mode
Tuesday, December 23, 2003
2003/357 21:45:02-21:18:37 Spacecraft Night
2003/357 22:02:34-22:03:11 Real-Time MOD_FR_MODE('DAY') Formatter Science Packets in Day Mode
2003/357 22:05:05-22:05:40 Real-Time MOD_FR_MODE(‘NIGHT’) Formatter Science Packets in Night Mode
2003/357 23:57:11-00:05:59 ATC MOD_OA16_SDSM_SCRN_NO_DOOR_A.4 OA-16: SD/SDSM screened side A, no door movement
Wednesday, December 24, 2003
2003/358 06:32:43-06:41:31 ATC MOD_OA16_SDSM_SCRN_NO_DOOR_A.4 OA-16: SD/SDSM screened side A, no door movement
2003/358 11:29:21-11:38:09 ATC MOD_OA16_SDSM_SCRN_NO_DOOR_A.4 OA-16: SD/SDSM screened side A, no door movement
2003/358 15:05:02-15:06:20 MOD_BB_ON(‘A’,’A’) Powers ON the Black Body
2003/358 15:06:39-15:07:10 MOD_SET_BB_TEMP(1284) Sets the Black Body temperature to 290K
2003/358 17:20:57-17:21:47 MOD_DCRESTORE(‘OFF’,’OFF’) Turns OFF DC Restore
2003/358 17:22:05-17:22:40 MOD_FR_DELTA(-3400) Sets the encoder scan delta to –3400 counts
2003/358 18:51:23-18:51:56 MOD_FR_DELTA(0) Returns the encoder scan to nominal position
2003/358 18:52:13-15:53:03 MOD_DCRESTORE(‘ON’,’ON’) Turns ON DC Restore
2003/358 20:20:01-20:24:16 MOD_NAD_TO_OPEN Opens Nadir Aperture Door
Thursday, December 25, 2003
None
Friday, December 26, 2003
None
This Week’s Scheduled MODIS Activities Not Completed:
None
Upcoming MODIS Events:
Tuesday, December 30, 2003
2003/364 20:45:22-20:54:10 ATC MOD_OA16_SDSM_SCRN_NO_DOOR_A.4 OA-16: SD/SDSM screened side A, no door movement
Wednesday, December 31, 2003
2003/365 21:27:59-21:30:30 ATC MOD_OA27_PV_ECAL.3
Maneuvers:
The next Lunar Calibration will occur on DOY 2004/012 (January 12, 2004), with a data collect time from 08:19:02 to 08:25:32. The necessary roll angle is - 0.2827 degrees. This is a small enough angle that the moon may be viewed through the Space View Port (SVP) without needing the spacecraft to perform a roll. Therefore, no roll will be performed for this calibration. However, the MODIS data will be adjusted for Day Rate and Sector Rotation as is standard for a Lunar Calibration.
MODIS Anomalies:
MODIS NAD Door Anomaly:
On Wednesday, December 24, 2003 at 20:20:01 (DOY 2003/358), the MODIS Nadir Aperture Door (NAD) was commanded to OPEN. A situation that was expected from previous NAD movements, the "NAD Open" trigger (MOD_CR_DR_NAD_OPEN) did not register from the door movement (it did not change from "NOT_OPEN" to "OPEN" as one would expect). This was anticipated as a possibility. The "NAD Closed" trigger did perform as expected; several seconds after the CP noted it was moving the NAD, the trigger value changed from "CLOSED" to "NOT_CLOSED". This shows the door did move at least enough to allow that trigger to release. The PS1 input current profile looked nominal while the door driver was powered. The CP generated the expected xx69 "NAD Trigger Not Found" from the command door movement with lack of trigger response. However, the door does appear to be OPEN as seen from the data from the Rapid Response team. Science data also appears to be nominal.
The NAD OPEN trigger may yet “pop” to OPEN due to thermal cycling on the trigger, as was seen on 2002/079.
Terra ACE Anomaly and Safe Mode:
MODIS has recovered from this anomaly and is now back in SCIENCE mode. See the Non-MODIS Significant Events section below for more details.
Terra SSR Anomaly:
Although not directly the result of a MODIS problem, the most recent Printed Wire Assembly (PWA) failures in the Terra Solid State Recorder (SSR) do affect MODIS data. See the Non-MODIS Significant Events section below for more details.
Terra SFE Anomaly:
Although not directly the result of a MODIS problem, the SFE anomaly is causing an unrecoverable loss of all current MODIS Direct Broadcast data. Normal science data recording and playbacks are functioning properly. See the Non-MODIS Significant Events section below for more details.
General Instrument Comments:
MODIS is in Science Mode, using all A-side components, but cross-strapped to Formatter B, with the blackbody maintained at 290K and the Solar Diffuser Door at the Screened position.
MODIS Telemetry Trends:
Nominal telemetry trending is ongoing.
Non-MODIS Significant Events:
Terra Solid State Recorder Anomaly
Overview:
The SSR Anomaly is still under investigation. MODIS currently is operating with 34 Supersets allotted for its buffer. There are plans in the works for possibly power cycling the SSR to get back PWA’s that are in the Bad List, but no date has yet been set. There are no current plans for a change in science data capture rates. For details, see previous reports.
Terra SFE Anomaly
Overview:
The SFE-A on Terra is corrupting every fourth byte of data it produces for the DAS-1 feed to the Direct Broadcast equipment. Terra direct broadcast is currently not operational. For details, see previous reports.
Terra ACE Anomaly and Safe Mode
Overview:
The Terra spacecraft and instruments were commanded to Safe Mode after the FDIR was tripped due to questionable data being received by the GNC subsystems. It has since been brought back to Normal Mode and all instruments are collecting science data. See below for details.
Details:
The Terra FOT has determined that the Safe Hold may have been caused due to problems within the Guidance Navigation and Control (GNC) Bus Data Unit (BDU). The Inertial Reference Unit (IRU) (where the 3 gyros are kept) saw 5 bad data samples (outside of acceptable limits) and the Fault Detection Isolation and Recovery (FDIR) transitioned it into Safe Mode. However, there were 2 good samples seen just prior to going into Safe Mode, but it was too late for the FDIR to stop what it was doing. There is still no word yet on what the cause was for the bad data samples (another SEU?), but the FOT is looking into the serial interface between the BDU and Attitude Control Electronics (ACE).
On Saturday, December 20, 2003 at 14:30 GMT (DOY 2003/354), Terra FOT switched control over from ACE- A Safe Mode to ACE-B Safe Mode. ACE-B was the component that saw the suspicious telemetry in the IRU that the FDIR keyed off of to initiate the Safe Mode transition. No anomalous telemetry was seen and the spacecraft appeared to be nominal. The reactivation of the FIDR and return to SCC controlled fine pointing mode for the spacecraft began at 17:50 GMT and completed at 19:10 GMT.
On Monday, December 22, 2003 at 21:43:10 GMT (DOY 2003/356), MODIS was transitioned to STANDBY mode. The SVD was opened at 21:46:10, and MODIS went into SCIENCE mode at 22:33:57. Cool down of the cold focal planes lasted 2 days, during which time 3 SDSM SCREENED activities were executed via ATC load. On DOY 2003/358 at 15:05:02 GMT, the black body was turned on and heated to 290K. The NAD was commanded to OPEN at 20:20:01 GMT.
The EMOS mission status webpage (which includes instrument data loss records) can be found at the following URL. Note that a password is now required to access the EOS mission links web pages. There are directions at the URL below for how to obtain a username/password.
http://jupiter02.gsfc.nasa.gov/links/links.htm
Limited Life Item Status:
SRCA 10W Lamp #1: 222.7 of 500 hours
SRCA 10W Lamp #2: 163.5 of 500 hours
SRCA 10W Lamp #3: 172.7 of 500 hours
SRCA 10W Lamp #4: 62.2 of 500 hours
SRCA 1W Lamp #1: 564.9 of 4000 hours
SRCA 1W Lamp #2: 276.7 of 4000 hours
Solar Diffuser Door: 2146 of 3022 Movements
Nadir Aperture Door: 538 of 1316 Movements
Space View Door: 441 of 1316 Movements