PDS_VERSION_ID        = PDS3
RECORD_TYPE           = STREAM
OBJECT                = TEXT
 PUBLICATION_DATE     = 1999-03-23
 NOTE                 = " E-mail and other messages
                          concerning MGS Radio Science on
                          or about 1997/133."
END_OBJECT            = TEXT
END


From trish@rodan.jpl.nasa.gov Tue May 13 16:35:20 1997
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Date: 13 May 97 16:41:59 -0700
From: Trish Priest <trish@rodan.jpl.nasa.gov>
Subject: More on MGS safing
To: John Armstrong <john@oberon.jpl.nasa.gov>,
        Georges Balmino <balmino@pontos.cnes.fr>,
        David Hinson <hinson@nimbus.stanford.edu>,
        Richard Simpson <rsimpson@magellan.stanford.edu>,
        Bill Sjogren <William.L.Sjogren@jpl.nasa.gov>,
        David Smith <dsmith@ltpsun.gsfc.nasa.gov>,
        Len Tyler <len@nova.stanford.edu>,
        Richard Woo <richard@oberon.jpl.nasa.gov>,
        Maria Zuber <zuber@tharsis.gsfc.nasa.gov>
Cc: Sami Asmar <Sami.W.Asmar@ccmail.jpl.nasa.gov>,
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Status: RO

Hello,

More news from the hallway:

The safing has been duplicated in the TDL lab.  Apparently contingency mode
sent the spacecraft flight software into a loop.  They do not know the
exact scenario yet.  The result was that neither CPU sent the "I'm okay"
status, so MGS went into safing.

The spacecraft is now communicating at 10 bps.  The link margin is not
sufficient to support 250 bps, especially since the spacecraft is tilted
down with respect to the Sun for temperature reasons.  At this rate the
telemetry stream only indicates that the USO is on, there is no USO
temperature information.

The Project wants a slow and careful recovery.  The projected recovery
time is the middle of next week.

Gyro 2 had anomolously high current, so it had to be shut off.

I will continue to send updates as I receive information.

-Trish