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From: starrfie@hydro.la.asu.edu (Sumner Starrfield)
Subject: Mars Observer Update - 08/27/93
Date: Fri, 27 Aug 93 11:16:23 MST
MARS OBSERVER STATUS REPORT
August 27, 1993
7:30 AM PDT
Beginning at about 3:00 PM Thursday, commands were sent to the spacecraft to
power on its transmitter on the basis that additional autonomous fault
protection activities had begun on the spacecraft. Those activities should have
oriented the spacecraft in a sun-pointed attitude, rotating in a manner in
which each of the two wider-angle-of-reception, low data rate antennas would
sweep the Earth's direction approximately every fifty minutes.
Commands were sent repeatedly over a period of five hours to insure the
greatest chance of being received at the spacecraft, and were sent both to the
point in space the spacecraft would have reached had Mars Orbit Insertion not
taken place as planned, and to the position where the spacecraft would be had
the MOI maneuver executed successfully. No carrier or telemetry has been
received as would be the case if this approach was successful.
After careful consideration, the command to "power on reset" the primary
Standard Control Processor was transmitted at 1:07 AM this morning to the fly
by predicted position, and at 4:30 AM to the on-orbit coordinates. The result
of that command would be to trigger Safe Mode. The decision will be made this
morning whether to send a command to power on the spacecraft transmitter or to
let Safe Mode clock out for its approximately 65 hour waiting period.
With that option exercised, the Flight Team will have utilized all presently
understood recovery approaches. We would then have to remain in a listen-only
mode in the event that on-board fault protection remains able to restore
communication with the ground.
This status will be updated during the day and evening as information becomes
available.
Return to the Powerful Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
