Mars Global Surveyor Status Report 30 August 2000
Wednesday, August 30, 2000 (DOY 236/19:00:00 to DOY 243/19:00:00
UTC)
Launch / Days since Launch = Nov. 7, 1996 / 1393 days
Start of Mapping / Days since Start of Mapping = April 1, 1999 / 517 days
Total Mapping Orbits = 6,617
Total Orbits = 8,220
Recent Events:
Background Sequences — The spacecraft continues to operate nominally
in performing the beta-supplement daily recording and transmission of science
data. The mm064 sequence executed successfully from 00-237 (8/24/00) through
00-239 (8/26/00). The mm065 sequence has performed well since it started
on 00-240 (8/27/00). It terminates on 00-243 (8/30/00). The mm066 sequence,
successfully uplinked on 00-242 (8/29/00), begins executing on 00-244 (8/31/00).
Other – The mz054 mini-sequence containing the MOLA Polar Scans was uplinked
00-241 (8/28/00). Between 00-243 (8/30/00) and 00-246 (9/2/00) MGS will
specifically target the North and South poles with the laser altimeter during
thirteen orbits covering 360 degrees of latitude.
Spacecraft Health:
All subsystems report nominal health. As MGS approaches aphelion, the
average energy margin per orbit is dropping as expected. Power projections
indicate that the average energy margin per orbit will drop below the 40
Watt-hour threshold between early September 2000 and mid-January 2001.
Though the spacecraft is capable of operating nominally below this threshold,
the project has elected to maintain the average energy margin at or above
40 Watt-hours. The on-board command scripts that control solar array motion
will be modified to provide the desired margin. This change will take effect
00-251 (9/7/00).
Uplinks:
There have been 9 uplinks to the spacecraft during the last week, including
new star catalogs and ephemeris files, instrument command loads, and the
background sequences cited above. There have been 4,813 command files radiated
to the spacecraft since launch.
Upcoming Events:
The mm067 background sequence will be uplinked 00-245 (9/1/00). Radio
Science Occultation Egress Scans, scheduled for 00-252 (9/8/00) through
00-253 (9/09/00), are contained in the mz055 mini-sequence. It will be
uplinked 00-250 (9/6/00). MOC Focus Calibrations are scheduled for 00-262
(9/18/00) through 00-272 (9/28/00).
