From: Jet Propulsion Laboratory
Posted: Monday, February 18, 2002
Wednesday, February 13, 2002 (DOY 037/19:00:00 to DOY 044/19:00:00 UTC)
Launch / Days since Launch = Nov. 7, 1996 / 1925 days
Start of Mapping / Days since Start of Mapping = April 1, 1999 / 1049 days
Total Mapping Orbits = 13,124
Total Orbits = 14,807
Background Sequences - The spacecraft is operating nominally in performing daily recording and transmission of science data. The MM158B sequence has performed nominally since it started on 02-030 (1/30/02). It terminates on 02-058 (2/27/02).
Other - MGS successfully executed three Roll Only Targeting Opportunity (ROTO) imaging scans in the MZ158 and MZ159 mini-sequences. All ROTO events occurred on schedule and gyro biases converged within the hour allocated. We still see significant attitude corrections following each of the ROTOs. On 02-042 (2/11/02), we updated the Y-axis gyro low-rate scale factor to reduce gyro propagation errors during ROTOs. We are pleased to see a corresponding 27% reduction in gyro bias variations. We anticipate that the scale factor update will result in smaller attitude corrections in the next series of ROTOs. MGS has completed 225 ROTOs to date.
All spacecraft subsystems report good health and status. The TES team corrected a couple of TES instrument malfunctions that surfaced recently. The TES is now operating nominally.
There have been 28 uplinks to the spacecraft during the past week, including instrument command loads, new star catalogs and ephemeris files, a gyro scale-factor update, and the ROTO mini-sequences mentioned above. 6,172 command files have been radiated to the spacecraft since launch.
MGS will perform more ROTOs in the MZ161 and MZ162 mini-sequences.
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