Terra Weekly Mission Status Update 31 Aug – 6 Sep 2001

The Terra spacecraft is in nominal mode. All instruments are in nominal science mode.

The MODIS instrument continues to operate in normal science mode on Side A (Command Processor A, Power Supply 1). MODIS rate of formatter errors has increased recently at a regular cyclic pattern. An investigation is ongoing to try to determine any cause for the 1-day cyclic pattern and estimate how a continuing increase in rate could impact science data. MODIS data continue to be used to help government agencies and other organizations to deal with the effects of the numerous forest fires in the Western United States.

On September 5 there was a planned 4-hour TDRSS outage (between 248/20:30 and 249/00:30z) at the White Sands TDRSS Ground Terminal to perform system upgrades. This affected Terra’s use of TDRS 275 only and therefore had no impact to routine science dumps. Prior to this outage, testing was performed proving that the TDRS 275 Guam SGLT Housekeeping Playback Patch, which eliminated dropouts, is no longer needed since the ERPS system has been installed. The patch was removed during this four hour outage. No impact to operations.

Several MDA2BITE trips (High Gain Antenna Motor Drive Assembly opto-coupler SEU) occurred during this reporting period with no resultant non-recoverable data loss.

Ground testing with the commercial ground terminal at Svalbaard (SKS) is underway. In ground testing with this station via DataLynx, an extra 6 bytes have been appended to each command issued from the EOS Operations Center (EOC). Ground testing will continue until this problem is fully diagnosed prior to any testing involving the issuing of NO-OP commands to Terra via the SKS ground station.

Terra Plans:

• MODIS Calibration Roll Maneuver on September 7th
• Drag Make-up Maneuver on September 13th.