Terra Weekly Mission Status Update

Weekly Update Archive

January 28 - Febrary 3, 2005

Members of the ASTER science team were here this week to report their mission related status to Goddard personnel along with members from JPL and the LP DAAC. FOT members gave presentations on S/C status, SSR status, SWIR set point change status, and discussed the missing commands problem in a recent ATC load. This meeting was highly successful as GSFC came away with a better understanding of needs of the ASTER team as they did us.

A second meeting was held on 2/2/05 to discuss thruster gain changes needed when the propellant tank pressure falls below 150 psi. At present, tank pressure is ~170 psi. At this pressure, thruster efficiency is approximately 57%. As pressure continues to decrease, so does the firing efficiency. To mitigate this decrease, a gain change is needed to restore efficiencies to those found during launch (~90%). The proposed gain change is planned for sometime after the next set of inclination maneuvers (fall 2005). More work is planned on this topic.

WSC believes they has determined the cause for the series of S-band late acquisitions Terra was experiencing over the last month. The CREAM balloon project (flying around the South Pole) was using the S-band Multiple Access (SMA) TDRSS service that he believes Terra was picking up from its nadir pointing OMNI antenna. This theory accounts for most of the late acquisitions. Since the CREAM project ended on 1/27/05, we have not seen another late acquisition occurrence.