MODIS IOT Terra Weekly Report

Mission Operations Days: 2002/215 to 2002/221
August 2, 2002 20:00:00 GMT to August 9, 2002 20:00:00 GMT

Terra Spacecraft and MODIS Instrument Status:

This Week's Completed MODIS Activities:

None

None

None

None

None

2002/219 20:19:21-20:32:32 ATC OA16: SD/SDSM Screened, SDSM Fixed At Sun - A Side
2002/219 21:10:49-21:44:22 ATC OA19: SRCA Full Radiometric - A Side
2002/219 21:58:14-22:11:25 ATC OA15: SD/SDSM Open, SDSM Fixed At SD - A Side
2002/219 23:52:11-23:54:42 ATC OA27: PV ECAL

None

None

This Week's Scheduled MODIS Activities Not Completed:

None

Upcoming MODIS Events:

The remaining August 2002 calibrations: biweekly SD/SDSM calibrations. A lunar calibration via roll maneuver is also planned for August 27th.

Maneuvers:

A Terra Drag Make Up maneuver was performed on 2002/219 (August 7, 2002) at 18:18:00 with burn duration of 16seconds. The period of Low Fidelity Pointing was 17:40:00 to 19:43:30.

The next Terra MODIS Lunar Calibration Roll is scheduled for 2002/239 (August 27, 2002), with data collection from 21:21:53 to 21:28:23 GMT and a roll angle of -5.9785 degrees.

The sixth Terra inclination adjust maneuver has been pushed back to an unspecified date in September to facilitate Lockheed Martin development at Valley Forge for products to support long term planning of possible future inclination maneuvers.

The Terra Deep Space Calibration Maneuver is still postponed. The maneuver date is not expected until late summer of 2002.

MODIS Anomalies:

At approximately 2002/207-21:19 GMT there was an anomaly identified by several Command and Data Handling (C&DH) TAXI overflow errors. Three distinct time periods of errors were reported:

207/21:19 - 207/23:00
207/23:21 - 208/01:00
208/02:32 - 208/04:00

It appears that the errors were only being received while the MODIS blackbody duty cycle was at FULL (100%) and the blackbody temperature had stabilized at one of the temperature plateaus. At the nominal operating conditions (290K, duty cycle = THIRD) no overflow errors were being reported. EDOS reviewed the data during the time of the anomaly and reported that only MODIS engineering data packets were lost due to this anomaly.

This anomaly is still under investigation, but upcoming blackbody calibrations (performed quarterly) will be conducted without the temperature plateaus. The calibrations will be scheduled to have the blackbody cool to 270K, heat directly to 315K, cool back down to 270K, and then resume the nominal 290K temperature.

Formatter Error Events:

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 48 million errors per day.

Intermittent bad frame count formatter event messages (xx1B) are being observed. This is one of the event messages being used to warn of potential impacts to the science data. The MODIS halt memory transfer command is being sent after each 1B-event message. This command triggers both a CP and FR event message and thus "clears" the current MOD_SS_FR_LAST_EVENT message of the xx1B value.

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.

General Instrument Comments:

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

MODIS Telemetry Trends:

All systems appear to be functioning properly. 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: 1895 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