Terra Weekly Mission Status Update 10-16 Aug 2001

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

MOPITT continues to operate with one cooler, allowing useful data to be collected for Channels 5-8. However, as a result of the Chopper 3 anomaly which leaves the chopper in the fully open position, data on Channels 5 and 6 are degraded. Via modifications to the processing techniques, it is expected that useful data will ultimately be obtainable from Channels 5 and 6 again, as long as Chopper 3 remains in the fully open position. The cause of the Chopper 3 anomaly is still under investigation. Preliminary analysis indicates a blown fuse. Channels 7-8 are still operating at 100 percent.

Data from the roll calibration maneuver for MODIS were analyzed by the MOPITT team and confirmed that the motion and change in attitude of the spacecraft during this maneuver had not caused Chopper 3 to move from the fully open position.

The MODIS instrument continues to operate in normal science mode on Side A (Command Processor A, Power Supply 1). A summary on the anomaly has been provided. Discussions continue on the potential transition back to B-side components. MODIS calibration roll maneuvers are being planned on a monthly basis.

The CLAMS field campaign involving Terra is completed. MODIS, CERES, and MISR continue to participate in CLAMS. Having successfully completed its Wallops Island deployment as an adjunct to CLAMS, the AirMISR instrument was transported back to JPL on August 10. It will now spend approximately six months undergoing routine maintenance, repairs, and upgrades prior to the start of campaigns next year.

Several MDA2BITE trips (High Gain Antenna Motor Drive Assembly opto-coupler Single Event Upsets) occurred during this reporting period with no resultant non-recoverable data loss. However, one event on August 15 resulted in the loss of a very small amount (3894 CADUs) of science data due to the inability to perform a replay due to the loss of telemetry.