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Mars Pathfinder Update #2 - October 1, 1997

MARS PATHFINDER MISSION STATUS
1 October 1997, 4:00 p.m. PDT

The Pathfinder team used today's passes over the 70 meter
Deep Ppace Network stations in Canberra and Madrid, to
attempt to get engineering data from the spacecraft.
Although we were not able to obtain engineering data as
we had hoped, we did learn another important piece of
information that has assisted us in putting more pieces
of our puzzle together. By watching the signal from
Pathfinder's auxiliary transmitter were able to see when
the spacecraft powered on this morning. The power on was
later than expected due to what appears to be extra loads
on the spacecraft. We believe that these loads may be the
result of some hardware failure, or may have been caused
by sequences that run every morning when the spacecraft
wakes up.

Normally execution of our morning sequences is not a
problem. However, since we believe that the spacecraft
battery may no longer be operating ,the spacecraft has
lost track of time. This loss of time causes loads to be
turned on when there may not be enough power to support
them. The initial lack of power is due to the fact that
the Sun has not risen high enough to fully illuminate the
solar panels and provide the required power. The
spacecraft will not power on until it determines that
there is enough power to operate its critical systems.

This will cause the spacecraft to wake up later in the
morning and power off sooner in the afternoon than we
would normally expect. This may explain some of the
behavior we have been seen in the last several days.
Tomorrow we will once again attempt to receive
engineering telemetry data from the spacecraft. We will
also be sending commands to put the spacecraft in the
safest state possible for the current no battery
situation. This will include taking the battery off-line.
We expect to receive signals from the auxiliary
transmitter indicating the completion of certain events
that have been executed to save the spacecraft.

Although the exact causes of our communication problems
have not been identified, we do believe that they are
related to the degradation of the spacecraft battery. We
have over the past two days received good indication that
the spacecraft is commandable and able to communicate
with us via the auxillary transmitter.

This information means that we can continue to operate
the spacecraft. The spacecraft will gradually move
towards using the other antennas and transmitters and
will verify they are operating correctly.

For further information on the Mars Pathfinder Mission,
please call our Mission Status Report line ,at
1-800-391-6654.