Press Release

Mars Global Surveyor Mission Status

By SpaceRef Editor
January 5, 2000
Filed under

Wednesday, January 5, 2000 (DOY 356/19:00:00 to DOY 005/19:00:00 UTC)

Launch / Days since Launch = Nov 7, 1996 / 1155 days

Start of Mapping / Days since Start of Mapping = April 1, 1999 / 279 days

Total Mapping Orbits = 3707

Total Orbits = 5389

Recent Events:

The mm010 sequence continues executing nominally the daily science record and playback events. The
mm010 sequence runs through
January 12.

The initial Mars Polar Lander (MPL) landing site imaging campaign has been completed, with 19 targeted
scans across the predicted
1-sigma MPL landing ellipse having been executed. Unfortunately no obvious signs of the lander or its
parachute has been found at
this time. Note that the definition of the landing ellipse
continues to change as additional atmospheric data from Mars
Global Surveyor (MGS) is factored in. As a result, the current
landing site imaging mosaic may not reflect the latest landing
site knowledge. Additionally there were some gaps in the mosaic
due to lost data at the Deep Space Network (DSN) stations. As a
result, a second set of imaging scans is being planned to fill in the gaps and to expand the coverage area
in response to the latest atmospheric data.

In addition to completing the MPL scans, a special targeted
opportunity to image the Mars Pathfinder (MPF) landing site was
performed Sunday December 26 at 09:18 UTC. Unfortunately due to an error in the coordinate system
used to derive the targeted
attitude, the wrong site was imaged. A second opportunity to image the Pathfinder landing site occurs on
Sunday January 9. The mz034 mini-sequence will be built on January 6 and 7 to perform the MPF and
additional MPL landing site imaging, and will execute through January 12.

The spacecraft has behaved almost flawlessly in performing all of the imaging scans.

High Gain Antenna (HGA) Anomaly:

The HGA inner gimbal angle continues to decrease and is currently at 53.5 degrees. The inner gimbal angle
will continue decreasing, reaching the location of the gimbal obstruction at 41.5 deg in
early February. Spacecraft Test Laboratory (STL) testing begun for validation of the HGA beta
supplement operations plan, which will be used to perform mapping operations for the rest of the nominal
mapping mission.

Spacecraft Health:

All subsystems are reporting nominal health. As reported
previously, battery 2 switched from VT curve 2 to VT curve 1 as a result of performing the MPL scans.
This was expected and resulted in slightly higher battery 2 temperatures. Upon completion of the initial
MPL and MPF scans, the Battery 2 VT curve was switched
back to VT2. Soon after though the flight software autonomously
re-commanded battery 2 back to VT1, which is where we will leave it. The trend indicates that battery 1
will shortly switch to VT1 as well.

Uplinks:

There have been 42 uplinks to the spacecraft during the last two weeks, including new star catalogs and
ephemeris files and
instrument command loads. Total command files radiated to the
spacecraft since launch is 4300.

Upcoming Events:

1) The mm011 sequence is currently in development and is scheduled for uplink Monday January 10, with a
sequence start time of
January 13 00:00 UTC.

2) The mz034 sequence to continue imaging the MPL and MPF landing sites is scheduled for development
on January 6 and 7, to begin
execution on Sunday January 9.

SpaceRef staff editor.