Mars Global Surveyor Status Report 13 Feb 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

Recent Events:

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.

Spacecraft Health:

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.

Uplinks:

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.

Upcoming Events:

MGS will perform more ROTOs in the MZ161 and MZ162 mini-sequences.