Mars Global Surveyor Status Report 3 Oct 2001

Wednesday, October 3, 2001 (DOY 269/19:00:00 to DOY 276/19:00:00 UTC)

Launch / Days since Launch = Nov. 7, 1996 / 1792 days

Start of Mapping / Days since Start of Mapping = April 1, 1999 / 916 days

Total Mapping Orbits = 11,498

Total Orbits = 13,181

Recent Events:

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 – Three Roll Only Targeted Observations (ROTOs) were performed this
past week. All three occurred during scheduled communications orbits.
Previously, MGS had been restricted to performing ROTOs only during
non-communications orbits. This new capability of performing ROTOs during
communications orbits will allow MGS to perform ROTOs during the Odyssey
aerobraking support phase, when MGS has 24 hours of DSN coverage each day.
MGS has completed 201 ROTOs to date.

Spacecraft Health:

All subsystems report good health and status.

The MOLA instrument team has completed their investigation of the MOLA
anomaly of 01-181 (6/30/01). The collective results from the instrument
tests indicate the anomaly was caused by an interruption of the 100-MHz
signal from the precision oscillator in the MOLA altimeter electronics.
Without the oscillator signal, the 10-Hz laser trigger signal cannot occur
and the laser cannot fire. All testing since July, 2001 shows that the
instrument responds properly to commanding and that all other parts of the
MOLA are operating normally. The diagnostic tests also demonstrated that the
MOLA is fully capable of continuing to collect data in passive radiometer
mode.

Uplinks:

There have been 19 uplinks to the spacecraft during the past week, including
new star catalogs and ephemeris files, instrument command loads, and the
MZ137 and MZ138 ROTO mini-sequences. 5,790 command files have been radiated
to the spacecraft since launch.

Upcoming Events:

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.

Five MOC defocus calibrations will be performed between 01-281 (10/8/01) and
01-289 (10/16/01).

A fifth and final MOLA diagnostic test will be conducted on 01-283
(10/10/01) after which the MOLA will be left on to operate in passive
radiometer mode.