MODIS IOT Terra Weekly Report

Mission Operations Days: 2001/342 to 2001/348
December 7, 2001 20:00:00 GMT to December 14, 2001 20:00:00 GMT

Terra Spacecraft and MODIS Instrument Status:

This Week's Completed MODIS Activities:

None

None

None

2001/345 19:46:12 Real-Time MOD_ALARMS_CP_ST_06(‘enabled’) procedure executed to clear the yellow alarm.
2001/345 22:25:50 – 22:26:34 Real-Time MOD_MEM_DUMP(6,16,45312,0,1,1) dumped formatter error addresses
2001/345 22:26:50 – 22:27:37 Real-Time MOD_MEM_DUMP(6,16,45568,0,1,1) dumped formatter error counts
2001/345 22:28:06 – 22:28:28 Real-Time Cleared the formatter error address buffer MOD_MEM_LOAD('AM1_MPR_MODIS_FR_P_C_C_1', 16, 'N', 'DISABLE', 1, 1)
2001/345 22:28:50 – 22:29:14 Real-Time Cleared the formatter error address count buffer MOD_MEM_LOAD('AM1_MPR_MODIS_FR_P_C_C_2', 16, 'N', 'DISABLE', 1, 1)
2001/345 22:29:29 – 22:29:34 Real-Time MOD_ALARMS_CP_ST_06(‘enabled’) procedure executed to clear the yellow alarm.
2001/345 22:29:56 – 22:30:38 Real-Time MOD_MEM_DUMP(6,16,45312,0,1,1) dumped formatter error addresses
2001/345 22:31:05 – 22:31:52 Real-Time MOD_MEM_DUMP(6,16,45568,0,1,1) dumped formatter error counts
2001/345 22:32:29 – 22:33:07 Real-Time Door inhibit ID 34 set
2001/345 22:33:01 – 22:33:20 Real-Time Door inhibit ID 58 set

Bi-Monthly PC and PV ECALs 2001/346 15:33:22-15:35:52 ATC OA-27: PV ECAL
2001/346 17:11:15-17:15:46 ATC OA-28: PC ECAL

Inclination Adjust Maneuver
2001/347 12:08:09 – 12:33:09 First TDRS contact
2001/347 12:56:29 – 13:15:50 Second TDRS contact
2001/347 13:44:56 – 14:15:30 Third TDRS contact
2001/347 14:33:43 – 14:58:43 Fourth TDRS contact
2001/347 14:45:00 – 14:47:18 Real-Time NADIR door commanded closed MOD_NAD_TO_CLOSED
2001/347 14:47:52 – 14:48:41 Real-Time Dump NADIR door table using MOD_MEM_DUMP(144,12,0,0,1,1)
2001/347 15:21:00 – 16:12:00 Fifth TDRS contact
2001/347 15:23:15 Real-Time Door inhibit ID 58 cleared
2001/347 15:23:41 Real-Time Door inhibit ID 34 cleared
2001/347 15:34:30 Begin –90 degree yaw
2001/347 15:36:20 Enter spacecraft night
2001/347 15:42:00 Complete –90 degree yaw
2001/347 15:44:30 Begin delta-i burn
2001/347 15:49:50 End delta-i burn
2001/347 15:58:00 – 16:05:30 ATC return slew commanding
2001/347 16:04:40 Real-Time Door inhibit ID 34 set
2001/347 16:04:54 Real-Time Door inhibit ID 58 set
2001/347 16:10:09 Enter Spacecraft Day
2001/347 16:20:30 – 16:45:50 Sixth TDRS contact
2001/347 16:26:23 – 16:29:00 Real-Time Stepped NADIR door open using MOD_STEP_DOOR(‘NAD’,3622,’OUT’)
2001/347 16:38:41 – 16:39:56 Real-Time Dump NADIR door table using MOD_MEM_DUMP(144,12,0,0,1,1)
2001/347 17:16:00 – 17:36:00 Seventh TDRS contact
2001/347 17:32:15 Real-Time Door inhibit ID 58 set
2001/347 17:32:52 Real-Time Door inhibit ID 34 set

None

This Week's Scheduled MODIS Activities Not Completed:

None

Upcoming MODIS Events:

None

None

None

None

None

None

None

None

SD/SDSM calibrations and the monthly SRCA Full Radiometric will be scheduled during the upcoming week. The rate of SDSM Calibrations has been reduced to one set (OA15 and OA16) every two weeks (half the previous rate). This planned reduced usage is done to extend the lifetime of the SD.

Maneuvers:

On December 13, TERRA performed the first of six burns for it's inclination adjust maneuver. The plan was to close the MODIS nadir aperature door, yaw the spacecraft 90 degrees, perform a 320 second inclination burn, yaw the spacecraft back 90 degrees, and open the NAD. If the burn was not nominal, and the yaw back was not completed, the SVD was going to be commanded closed via the ATC load. As it turns out, the adjust was successful, so the SVD was not commanded close.

The other 5 inclination burns will be spread out between now and May of 2002. The burns are planned to maintain 10:30 +/- 00:05 mean local equator crossing time. The next 5 dates for the burns are:

January 16, 2002
February 13, 2002
March 13, 2002
April 17, 2002
May 15, 2002

Next Drag makeup maneuver is scheduled for December 18.

The next MODIS Lunar Calibration via a spacecraft roll maneuver is scheduled for January 3rd, 2001 (2002/003) with data collection from 11:13:22 to 11:19:52. The roll angle will be -1.9741 degrees.

Preliminary plans have begun for a Deep Space Calibration Maneuver. The execution date is expected to fall in the first week of March 2002.

MODIS Anomalies:

Even though the spacecraft inclination adjust was nominal, closing the MODIS NAD was not. At 14:45:00, a real-time command was sent to close the NAD. When the command went out to close the door, the software indicated that the door was stepping shut, but the telemetry point MOD_CR_DR_NAD_OPEN remained in the OPEN state, rather than the expected NOT_OPEN state. It was not until an anxious few seconds later when the door steps went to zero, and the telemetry point MOD_CR_DR_NAD_CLSD went from NOT_CLOSED to CLOSED, that it was verified that the NAD actually shut. A MODIS memory dump of table #18, MOD_MEM_DUMP(144,12,0,0,1,1), was performed after the door closed, and it indicated that the NAD closed microswitch was tripped with a door step count of 9. The NAD open microswitch still indicated OPEN.

Usually, to open the NAD the procedure MOD_NAD_TO_OPEN is executed. However, since the door was already indicating OPEN, this procedure would not command it to do so. Instead, the procedure MOD_STEP_DOOR(‘NAD',3622,'OUT') was executed to step the NAD door out 3622 steps to where it was originally. The telemetry point MOD_CR_DR_NAD_CLSD changed from CLOSED to NOT_CLOSED, and MOD_CR_DR_NAD_OPEN remained in the OPEN state. A second door table dump was performed and it indicated that the NAD open microswitch was not tripped when the door was stepped open, as expected. Another verification to the door opening was a real-time direct broadcast to Goddard while the door was being moved open. The data confirmed that the door did reopen.

A review of the failed door telemetry anomaly will certainly take place, but a location and time have not yet been identified.

Formatter Error Events:

As of December 14th, 2001, approximately 5.4 million formatter errors have been logged. Approximately 100,000 errors are being recorded each day, which causes the MOD_SS_CP_STATUS_08 counter to “roll over” about every 8 hours. Ten unique error addresses have been captured since the address buffer was last cleared on December 11.

The FR Error Rate roll over period has been fluctuating between eight and nine hours since the middle of November. The period decreases and increases based on cooling or heating (respectively) of the MODIS electronics from internal calibrations (BB, SRCA, and SD/SDSM) activities. However, once an activity has completed, and the MODIS electronic thermal balance returns to “non-activity” levels, the error rate resumes its normal course.

Error tracking spreadsheets have been updated and can be retrieved from:

ftp://www.mcst.ssai.biz/ftp/pub/permanent/IOT/am1/analysis/FR_events/

An MS Excel spreadsheet called, AM1_FR_error_rollovers_MMDDYY.xls contains the data for the times each of the error count “roll over” occurs (with the MMDDYY denoting the date the spreadsheet was made, the more recent date containing the most up-to-date information).

General Instrument Comments:

MODIS is in Science Mode on the A-side with the SVD and NAD open, operating with the Formatter Resolution Flight Software Patches (FRFSP).

Note: SD/SDSM calibrations have been decreased to a single OPEN and SCREENED calibration every two weeks.

MODIS Telemetry Trends:

As of 2001/334, Terra's solar beta angle is approximately 19.3 degrees and on the rise. By year's end, the beta angle will be nearly 24 degrees. With this the space view door temperature is expected to decrease and the focal plane heater power margin may increase slightly. The focal plane temperatures have been steady and no additional outgassing will be required in the near future.

Non-MODIS Significant Events:

Science Data Loss Reports can be viewed at:

http://jupiter02.gsfc.nasa.gov/

Select "Search Data Losses" and choose Data Type: MOD

Then press the big SUBMIT button.

Limited Life Item Status:

SRCA 10W Lamp #1: 192.7 of 500 hours
SRCA 10W Lamp #2: 147.1 of 500 hours
SRCA 10W Lamp #3: 156.3 of 500 hours
SRCA 10W Lamp #4: 61.5 of 500 hours

SRCA 1W Lamp #1: 558.6 of 4000 hours
SRCA 1W Lamp #2: 276.3 of 4000 hours

Solar Diffuser Door: 1775 of 3022 Movements
Nadir Aperture Door: 534 of 1316 Movements
Space View Door: 437 of 1316 Movements

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Last Update: Wednesday, 26-Feb-2003 16:32:31 EST