Terra Weekly Mission Status Update 9-15 Nov 2001

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

A Drag Make-up Maneuver was successfully executed on Thursday, November 15, 2001. The next Drag Make-up Maneuver is scheduled for early December.

ASTER Direct Downlink (DDL) testing over the Polar Ground Stations was executed successfully on November 1 and November 2. The Alaska Ground Station (AGS) provided spectrum plots of the X-band signal obtained during the passes. Additional testing will be conducted using the MODIS Direct Broadcast receiving dish at Goddard Space Flight Center in order to provide the ASTER team with additional data for use in the development and utilization of their DDL antenna.

A combination of ground system configuration and operations errors resulted in the loss of approximately 2,400,000 CADUs of ASTER data on Tuesday, November 13. An incorrect “buffer size” parameter for estimated data volume on board the Solid State Recorder (SSR) was passed to the on-line science replay procedure, resulting in the wrong command parameters being issued to the SSR. Future occurrences of this problem will be avoided by adding checks and warnings for the buffer size parameter.

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.

Plans

• Leonid meteor shower staff-up for November 18
• Continued certification testing with commercial polar ground station sites
• Continued planning for additional Polar Ground Station Science Data Downlink demonstrations and tests over GSFC