MODIS IOT Terra Weekly Report

Mission Operations Days: 2001/335 to 2001/341
November 30, 2001 20:00:00 GMT to December 7, 2001 20:00:00 GMT

Terra Spacecraft and MODIS Instrument Status:

This Week's Completed MODIS Activities:

None

None

None

MODIS Lunar Roll
2001/338 21:10 Real-Time IRU set to High Rate (lower spacecraft attitude precision)

MODIS Lunar Roll (continued)
2001/339 03:04:43 ATC Formatter to Night Rate Set ahead by 03:23 to ensure 50/50 day/night data collection.
2001/339 03:36:58 ATC Formatter to Day Rate
2001/339 03:37:00 ATC SCIABNORM flag set to ABNORM
2001/339 03:37:02 ATC PV DCR computation to OFF
2001/339 03:37:04 ATC PC DCR computation to OFF
2001/339 03:37:06 ATC Sector rotation to 3072
2001/339 03:43:36 ATC Sector rotation to 0
2001/339 03:43:38 ATC PC DCR computation to ON
2001/339 03:43:40 ATC PV DCR computation to ON
2001/339 03:43:42 ATC SCIABNORM flag to NORM
2001/339 03:43:44 ATC Formatter to Night Rate
2001/339 03:59:54 ATC Formatter to Day Rate Set later by 03:23 to ensure 50/50 day/night data collection.
2001/339 04:10 Real-Time IRU set to Low Rate (greater spacecraft attitude precision)

2001/339 20:14:42-20:26:10 OA-15: SDSM Open
2001/339 21:53:35-22:05:03 OA-16: SDSM Screened

None

None

This Week's Scheduled MODIS Activities Not Completed:

None

Upcoming MODIS Events:

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

Inclination Adjust Maneuver

347/12:08:09 - 12:33:09 First TDRS contact

347/12:56:29 - 13:15:50 Second TDRS contact

347/13:44:56 - 14:15:30 Third TDRS contact

347/14:33:43 - 14:58:43 Fourth TDRS contact
Close Nadir Door MOD_NAD_TO_CLOSED

347/15:21:00 - 16:12:00 Fifth TDRS contact ***BURN CONTACT***
15:34:30 Begin -90 degree yaw
15:36:20 Enter spacecraft night
15:42:00 Complete -90 degree yaw
15:44:30 Begin delta-i burn
15:49:50 End delta-i burn
15:54:00 Begin return slew
16:01:30 End return slew
[15:59:00 - 16:06:30] ATC return slew commanding
16:06:30 - 16:09:00 Set inhibit IDs 34 & 58 if return slew is nominal FS1_EXEC_INHIB_ID_SET(34)
FS1_EXEC_INHIB_ID_SET(58) 16:09:09 ATC commanding for SVD to Closed (S/C to Day -00:01:00)
UNLESS Inhibit IDs 34 & 58 are set 16:10:09 Enter spacecraft day

347/16:20:30 - 16:45:50 Sixth TDRS contact

Dump door table MOD_MEM_DUMP(144,12,0,0,1,1)
Open Nadir Door MOD_NAD_TO_OPEN
Dump door table MOD_MEM_DUMP(144,12,0,0,1,1)
Clear inhibit IDs 34 & 58 if set FS1_EXEC_INHIB_ID_RST(34) FS1_EXEC_INHIB_ID_RST(58)

2001/347 17:16:00 - 17:36:00 Seventh TDRS contact

No SD/SDSM calibrations 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.

With the next set of SD/SDSM Activities, the monthly SRCA Full Radiometric will be performed.

Maneuvers:

Due to a sharp decrease in drag, the December 5th drag make-up maneuver has been postponed. The next DMU maneuver is expected to occur after the inclination maneuver (December 13th) but before the holidays.

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.

The current plan for Terra orbit inclination adjustment maneuvers is to perform six burns, one burn each month from December 2001 to May of 2002. The burns are planned to maintain a 10:30 +/- 00:05 mean local equator crossing time. The dates for the burns are:

December 13, 2001 (347/15:34:30 start)

It has been evaluated that the COM link for the previously scheduled maneuver (346/19:48:00) is not favorable due to an unwind condition of the HGA. The new time was evaluated to have a good communication link.

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

Currently, MODIS' planned configuration for the inclination maneuvers will be to close the Nadir Aperture Door and schedule a stored command to close the Space View Door before Terra would re-enter sunlight. The stored command will be inhibited if the return yaw slew goes nominally.

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:

Formatter Error Events:

As of December 6th, 2001, approximately 4.6 million formatter errors have been logged. Approximately 93,000 errors are being recorded each day, which causes the MOD_SS_CP_STATUS_08 counter to “roll over” about every 8-9 hours. Thirteen unique error addresses have been captured since the address buffer was last cleared.

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/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: 532 of 1316 Movements
Space View Door: 437 of 1316 Movements

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Last Update: Wednesday, 26-Feb-2003 16:28:30 EST