Mars Global Surveyor Status Report 9 May 2001
Mars Global Surveyor Status Report
Wednesday, May 9, 2001 (DOY 122/19:00:00 to DOY 129/19:00:00 UTC)
Launch / Days since Launch = Nov. 7, 1996 / 1645 days
Start of Mapping / Days since Start of Mapping = April 1, 1999 / 769 days
Total Mapping Orbits = 9,701
Total Orbits = 11,384
Recent Events:
Background Sequences – There have been no background sequences operating
since MGS entered C-Mode a week ago on 01-122 (5/02/01). Last week, the
mm135 sequence terminated approximately fourteen hours earlier than expected
due to C-Mode entry. The mm136 sequence, though uplinked, was prevented from
starting on 01-123 (5/3/01) by C-Mode. The mm137 sequence was never
uplinked. Recovery efforts have gone well the past two days and we expect to
start normal background sequencing with mm138. It will start today, 01-129
(5/9/01), at 23:57:00 UTC Spacecraft Event Time. mm139 is scheduled for
uplink on 01-131 (5/11/01). It will commence on 01-133 (5/13/01).
Other – No ROTOs or other special science scans were conducted this week.
The mz095 mini-sequence was used to return MGS to its normal NADIR pointing
attitude. It also triggered an on-board command script to control movement
of the HGA and operate the downlink transmitter during the transition from
C-Mode to nominal mapping. The mz096 mini-sequence was prepared in the
optimistic hope that we might recover in time to conduct a ROTO. It was
never uplinked due to the intense effort required to prepare and uplink the
C-Mode recovery command files. The mz098 mini-sequence was uplinked today to
terminate the HGA command script shortly before the mm138 background
sequence goes active.
Spacecraft Health:
All subsystems report good health and status. All science instruments have
been powered-on except the TES. The TES was powered-on, then off when it did
not respond correctly to the NIPC commands prepared by the TES Team. The TES
team suspects that the problem may be with the NIPC file itself and not the
with the TES instrument.
The Sun Monitor Ephemeris fault detection and response have been disabled to
prevent another C-Mode entry while the Spacecraft Team investigates the root
cause of the failure. Other fault protection routines will continue to
protect MGS from losing its attitude knowledge.
Uplinks:
There have been 66 C-Mode recovery uplinks to the spacecraft during the past
week. There have been 5,352 command files radiated to the spacecraft since
launch.
Upcoming Events:
The Radio Science Occultation Egress Scans contained in the mz097
mini-sequence should take place as scheduled on 01-133 (5/13/01) and 01-134
(5/14/01). An MGS Mars Relay On-orbit UHF Test, initiated by the Mars
Exploration Rover project, will be conducted with Stanford University on
01-135 (5/15/01) and 01-136 (5/16/01).
