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am1weekly_2001-244_2001-250

Mission Operations Days: 2001/244 to 2001/250
September 01, 2001 00:00:00 GMT to September 07, 2001 00:00:00 GMT


Terra Spacecraft and MODIS Instrument Status:

Terra (AM-1) is in Normal Ops Mode
MODIS is in Science Mode - A Side
ComponentState(s)Comment
BlackbodyA On (290 K); B OffNominal
Calibration ElectronicsA On; B OffNominal
Control ProcessorA On; B OffNominal
Nadir DoorUnlatched, OpenNominal
Space View DoorUnlatched, OpenNominal
Solar Diffuser DoorUnlatched, ClosedNominal
FDDI FormatterA On; B OffNominal
FDDI PortA On; B OffNominal
FIFO Memory#1 & #2 On; #3 & #4 OffNominal
Format ProcessorA On; B OffNominal
Power Supplies#1 On; #2 OffNominal
PV VIS FPAA On; B OffNominal
PV NIR FPAA On; B OffNominal
PV SMIR FPAA On; B OffNominal
PV LWIR FPAA On; B OffNominal
PC LWIR FPAA On; B OffNominal
RC Outgas HeatersAll Off (CS, IS, OS)Nominal
RC LWIR FPA HeaterOn (83 K)Nominal
RC SMIR FPA HeaterOffNominal
Scan AssemblyA On; B OffNominal
SDSMA Off; B OffNominal
SRCAA Off; B OffNominal
PS1 Survival HeaterEnabledNominal
PS2 Survival HeaterEnabledNominal
Timing GeneratorA Off; B OnNominal
Flight SoftwareRev BD + 2 set of patches
  • FR Error Counting and Statistics (2 patches)
  • FR Band 5 Gain Change (20 commands)
Nominal
Inhibit Ids SetNoneNominal
TMON 66 (SRCA A)DisabledNominal
TMON 67 (SRCA B)DisabledNominal
TMON 68 (FIFO)EnabledNominal
TMON 69 (EPS Current)DisabledNominal

This Week's Completed MODIS Activities:

Saturday, September 1, 2001

None

Sunday, September 2, 2001

None

Monday, September 3, 2001

None

Tuesday, September 4, 2001

2001/247 21:29:48 RT Dump the Formatter (FR) Error Address Buffer MOD_MEM_DUMP(6, 16, 45312, 0, 1, 1)
2001/247 21:40:53 RT Dump the FR Error Address Count Buffer MOD_MEM_DUMP(6, 16, 45568, 0, 1, 1)
2001/247 21:42:30 RT Clear the FR Error Address Buffer MOD_MEM_LOAD(‘AM1_MPR_MODIS_FR_P_C_C_1’, 16, ‘N’, ‘DISABLE’, 1, 1)
2001/247 21:43:32 RT Clear the FR Error Address Count Buffer MOD_MEM_LOAD(‘AM1_MPR_MODIS_FR_P_C_C_2’, 16, ‘N’, ‘DISABLE’, 1, 1)
2001/247 21:44:20 RT Disable the yellow limits on the FR Unique Address Error Counter. Numerous new events expected (yellow limit flag unnecessary). MOD_ALARMS_CP_ST_06(‘DISABLE’)
2001/247 21:48:58 RT Verify the Formatter (FR) Error Address Buffer Cleared MOD_MEM_DUMP(6, 16, 45312, 0, 1, 1)
2001/247 21:50:01 RT Verify the FR Error Address Count Buffer Cleared MOD_MEM_DUMP(6, 16, 45568, 0, 1, 1)

Wednesday, September 5, 2001

(Two orbits with SMIR Itwk/Vdet of 79/110)
2001/248 07:11:50 Set SMIR Itwk/Vdet 79/110
2001/248 11:03:57 Set SMIR Itwk/Vdet 79/190 ("nominal")

Thursday, September 6, 2001

2001/249 21:14:44-21:26:12 ATC OA-16: SD/SDSM Screened
2001/249 22:53:38-23:05:06 ATC OA-15: SD/SDSM Open

Friday, September 7, 2001

Lunar Roll Maneuver (-7.5106 degree roll)
2001/250/18:29 RT FOT Set IRU to high rate for roll maneuver; less pointing accuracy
2001/250/19:33:11 ATC Move Formatter to Night ahead by 3:23 to ensure 50/50 day/night
2001/250/19:59:01 ATC FOT begins spacecraft roll slew to –7.5106 degrees
2001/250/20:03:39 ATC Set Formatter to Day Rate
2001/250/20:03:41 ATC Set SCIABNORM Flag to ABNORM
2001/250/20:03:43 ATC Set PC band DC Restore to OFF
2001/250/20:03:45 ATC Set PV band DC Restore to OFF
2001/250/20:03:47 ATC Set Sector Rotation to –3072 (Earth Aperture to view Space view and OBCs)
2001/250/20:10:17 ATC Set Sector Rotation to Zero (Normal)
2001/250/20:10:19 ATC Set PV band DC Restore to ON
2001/250/20:10:21 ATC Set PC band DC Restore to ON
2001/250/20:10:23 ATC Set SCIABNORM Flag to NORM
2001/250/20:10:25 ATC Set Formatter to Night Rate
2001/250/20:15:08 ATC Spacecraft has returned to nominal attitude
2001/250/20:29:25 ATC Move Formatter to Day later by 3:23 to ensure 50/50 day/night
2001/250/20:22 RT FOT set IRU to low rate after roll maneuver; nominal pointing

This Week's Scheduled MODIS Activities Not Completed:

None

Upcoming MODIS Events:

Friday, September 7, 2001

None

Saturday, September 8, 2001

None

Sunday, September 9, 2001

None

Monday, September 10, 2001

None

Tuesday, September 11, 2001

None

Wednesday, September 12, 2001

SD/SDSM calibrations
SRCA Full Radiometric calibration

Thursday, September 13, 2001

SCRA Full Spatial calibration

Friday, September 14, 2001

None

Maneuvers:

The next Drag Make Up Maneuver will be performed on day 2001/256 at 19:25:00 lasting for 20 seconds.

The next Lunar Calibration roll maneuver is scheduled for day 2001/280 (October 7, 2001) with data collection from 07:10:54 to 07:17:24. The roll angle will be -11.3321 degrees.

MODIS Anomalies:

On DOY 247, the Formatter Error counts were dumped and then cleared to attempt to capture any events that were being missed due to the buffer limit of 15 error codes. At the time of the dump (noted above), the error counts were:

Error Address (HEX)Number of Occurrences (DECIMAL)
1f1a2,710
1f1e1,269
200d7,055
1f32301
1f261,089
20291,806
20252,378
20155,862
202d995
20115,403
201d4,566
20196,066

These total 44,360 of the 82,303 errors reported at the time of the memory dump.

The FR error counter (MOD_SS_CP_STATUS_06) has “rolled over” twice since the A-Side restart following the PS-2 Anomaly. This is a 16-bit signed counter, therefore it “rolls over” every 32,768 counts. At present (250/19:58:33.179), the counter is 19,576, which means that 85,112 errors have been seen since the A-Side restart.

A cyclic, increasing rate of Formatter errors has been detected. The increase in Formatter error rates occur at the same times we see decreases in the MOD_TP_FR_A_ENGINE, MOD_TP_ME_NX_HTSINK, and MOD_TP_ME_CHAS_TOP temperatures. The current trend of these mnemonics is a gradual decrease in temperature.

An MS Excel spreadsheet is available for download from:

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

This file contains the times for each FR error count as well as the three temperatures (from day 240 on) mentioned above. This file will be periodically updated with the most recent telemetry sets available. In this file, you can see a graph of this cyclic, increasing error rate. If you have any special requests, please let us know.

The current sustained maximum of the FR error rate is around 150 errors per hour (with shorter bursts that reach up to 300+ errors per hour). As of yet, no problems with the science data have been reported. If the error rate continues to increase, there is the possibility of brief interruptions in science data as the FR attempts to deal with the large amount of errors. At present we have no indication to what this threshold level for science data loss may be.

We are still in a "wait and see" mode right now. However, everyone should be encouraged to consider options (i.e. B-side) before we have no choices left.

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 were planned to be reduced to once per two weeks. This plan has been revised; SD/SDSM calibrations will continue to be scheduled once each week until the end of November.

MODIS Telemetry Trends:

Trending has resumed with the instrument on the A-side. With the currently decreasing beta angle, the amount of focal plane heater margin is increasing. The intermediate stage cooler temperature is stable.

The increase in formatter error events is also being trended (as described above) to aid in any future operational decisions necessary to maintain the health of the instrument and its science data.

Non-MODIS Significant Events:

None

Limited Life Item Status:

SRCA 10W Lamp #1: 189.1 of 500 hours
SRCA 10W Lamp #2: 144.8 of 500 hours
SRCA 10W Lamp #3: 154.0 of 500 hours
SRCA 10W Lamp #4: 61.5 of 500 hours

SRCA 1W Lamp #1: 558.0 of 4000 hours
SRCA 1W Lamp #2: 276.3 of 4000 hours

Solar Diffuser Door: 1697 of 3022 Movements
Nadir Aperture Door: 532 of 1316 Movements
Space View Door: 437 of 1316 Movements