MODIS IOT Terra Weekly Report

Mission Operations Days: 2002/243 to 2002/249
August 30, 2002 20:00:00 GMT to September 6, 2002 20:00:00 GMT

Terra Spacecraft and MODIS Instrument Status:

This Week's Completed MODIS Activities:

None

None

None

None

None

2002/247-18:10 Real-time FOT commands Terra Spacecraft to Low Fidelity pointing
2002/247-19:08 ATC Terra begins 15 second Drag Make-up maneuver
2002/247-20:37 Real-time FOT commands Terra Spacecraft to High Fidelity pointing

None

None

This Week's Scheduled MODIS Activities Not Completed:

None

Upcoming MODIS Events:

During the month of September, bi-weekly SD/SDSM calibrations, an SRCA Full Radiometric calibration, and an SRCA Full Spatial calibration are planned. In addition, a lunar calibration (via roll maneuver) is planned for September 26th, 2002 (2002/269).

Maneuvers:

The next MODIS lunar calibration maneuver is planned for September 26th, 2002 (2002/269). Data collection will be from 15:08:10 to 15:14:40 GMT and the roll angle will be -9.8585 degrees.

The sixth Terra inclination adjust maneuver is currently planned for September 25th, 2002 at approximately 15:54 GMT. There will be no change to the MODIS operations schedule for this event (although the SD/SDSM calibrations may shift by one day), but contingency Nadir Door and Space View door closing activities will be scheduled in case the return yaw slew is not successful.

The Terra Deep Space Calibration Maneuver is still postponed. The next possible maneuver date is currently being planned for December of 2002.

MODIS Anomalies:

The current patches loaded into the MODIS Formatter record the number of formatter error events, but not the address where they occurred. The error rate is approaching 60 million errors per day.

Intermittent bad frame count formatter event messages (xx1B) are still being received. An increase in xx17 and xx18 formatter event messages has also been observed. These messages indicate that one of the First-In-First-Out (FIFO) memory blocks has been swapped from the FDDI port before it was completely emptied. Any data still in the FIFO at the time of the error was lost. The last data written to the FIFO are the two frames of Engineering Data. Just prior to that are the Earth View Sector data.

If this problem truly does indicate that the MODIS science data are being lost, the Formatter may be switched from the A-side to the B-side. This may occur as soon as the week of September 18th. Updates regarding this configuration change will be distributed in e-mail notifications.

The most recent error tracking spreadsheets can be retrieved from:

An MS Excel spreadsheet in a WinZip compressed archive called, AM1_FR_error_rollovers_current.zip contains the data for the times each error count "roll over" occurs.

EDOS has reported that MODIS produced repeated data at several instances between days 2002/245 and 2002/249. In one case, 120 packets were repeated twelve times. There is not yet much information about this anomaly, and an investigation is underway.

General Instrument Comments:

MODIS is in A-side Science Mode with the blackbody maintained at 290K.

MODIS Telemetry Trends:

Tracking of the Formatter Error Rate is continuing.

Non-MODIS Significant Events:

Science Data Loss Reports can be viewed at:

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

Then press the big SUBMIT button.

Limited Life Item Status:

SRCA 10W Lamp #1: 201.0 of 500 hours
SRCA 10W Lamp #2: 152.8 of 500 hours
SRCA 10W Lamp #3: 162.0 of 500 hours
SRCA 10W Lamp #4: 61.5 of 500 hours

SRCA 1W Lamp #1: 559.8 of 4000 hours
SRCA 1W Lamp #2: 276.3 of 4000 hours

Solar Diffuser Door: 1907 of 3022 Movements
Nadir Aperture Door: 536 of 1316 Movements
Space View Door: 439 of 1316 Movements

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Last Update: Thursday, 04-Sep-2003 18:14:23 EDT