From: Jet Propulsion Laboratory
Posted: Wednesday, September 26, 2001
Mars Global Surveyor Status Report
Wednesday, September 26, 2001 (DOY 262/19:00:00 to DOY 269/19:00:00 UTC)
Launch / Days since Launch = Nov. 7, 1996 / 1785 days
Start of Mapping / Days since Start of Mapping = April 1, 1999 / 909 days
Total Mapping Orbits = 11,412
Total Orbits = 13,095
Background Sequences - The spacecraft is operating nominally in performing daily recording and transmission of science data. The mm153 sequence has performed well since it started 01-256 (9/13/01). It terminates on 01-290 (10/17/01).
Other - Delta-DOR experiments were performed on 01-267 (9/24/01) and 01-269 (9/26/01).
No Roll Only Targeted Observations (ROTOs) were performed this past week. ROTOs were temporarily suspended pending investigation of the C-Mode entry root cause. MGS entered C-Mode on 9/6/01 because the STAREX star processing software could not converge on a good inertial attitude following a ROTO. The ROTO did not cause the C-Mode entry, but STAREX performance following ROTOs may impact how we perform ROTOs in the future. MGS has completed 198 ROTOs to date.
All subsystems report good health and status. The spacecraft team is investigating ways to improve the probability that STAREX will converge on a good inertial attitude following each ROTO. The MOLA instrument team is still investigating the MOLA anomaly of 01-181 (6/30/01) and will be requesting a fifth diagnostic test in the near future.
There have been 16 uplinks to the spacecraft during the past week, including new star catalogs and ephemeris files, instrument command loads, and the MZ136A ROTO mini-sequence. 5,771 command files have been radiated to the spacecraft since launch.
On 01-270 (9/27/01), MGS will perform a ROTO during a communications orbit for the first time. Previously, MGS had been restricted to performing ROTOs only during non-communications orbits. Two more ROTOs during communications orbits are scheduled for the MZ037 mini-sequence.
A Solar Array (SA) and High Gain Antenna (HGA) flexible modes baseline diagnostic test will be performed on 01-278 (10/05/01). It is designated MZ139. Performing this test periodically should give us insight into any additional SA hinge or HGA gimbal degradation, if it occurs.
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