PDS_VERSION_ID        = PDS3
RECORD_TYPE           = STREAM
OBJECT                = TEXT
 PUBLICATION_DATE     = 2007-07-27
 NOTE                 = " E-mail and other messages
                          concerning MGS Radio Science on
                          or about 1997/271."
END_OBJECT            = TEXT
END


From len@nova.Stanford.EDU Mon Sep 29 10:47:47 1997
Received: from nova.stanford.edu (nova.Stanford.EDU [36.10.0.123]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id KAA16933 for <rsimpson@magellan.Stanford.EDU>; Mon, 29 Sep 1997 10:47:47 -0700 (PDT)
Received: from [36.10.0.171] (exh2.Stanford.EDU [36.10.0.171])
          by nova.stanford.edu (8.8.5/8.8.4) with SMTP
   id KAA08160; Mon, 29 Sep 1997 10:48:02 -0700 (PDT)
Message-Id: <199709291748.KAA08160@nova.stanford.edu>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Date: Mon, 29 Sep 1997 10:47:28 -0700
To: ahmad@nova.Stanford.EDU, rsimpson@nova.Stanford.EDU, joe@nova.Stanford.EDU,
        hinson@nova.Stanford.EDU, len@nova.Stanford.EDU,
        stoumpis@nova.Stanford.EDU
From: len@nova.Stanford.EDU (Len Tyler)
Subject: MGS Status, Saturday 9/27
Content-Length: 3946
Status: RO

>X-Sender: cwhetsel@pop.jpl.nasa.gov
>Mime-Version: 1.0
>Date: Sun, 28 Sep 1997 04:11:36 -0800
>To: msop@mgsw3.jpl.nasa.gov
>X-UIDL: 875539894.002
>From: "Charles W. Whetsel" <charles.w.whetsel@jpl.nasa.gov>
>Subject: MGS Status, Saturday 9/27
>Sender: owner-msop@mgsw3.jpl.nasa.gov
>Precedence: bulk
>Status: RO
>
>Saturday morning, shortly after periapsis 9, the MGS spacecraft was
>commanded into Contingency Mode, in an attempt to correct a perturbation to
>the spacecraft's star processing algorithm which had been introduced
>following aerobraking maneuver 4 on September 23rd.
>
>DSN stations 45 and 43 in Canberra, Australia supported the activity.
>After the stations had locked up on spacecraft telemetry via the low-gain
>antenna at the emergency downlink rate of 10 bits per second, the flight
>team in Denver and Pasadena were able to determine that the spacecraft
>health was excellent and stable following the event.  Command radiations to
>initiate the spacecraft recovery process were issued shortly thereafter.
>In record breaking time, the spacecraft flight software was able to
>re-establish it's inertial reference (with respect to the stars) in the
>Sun-Star Initialization mode, which was commanded following the spacecraft
>Contingency Mode entry.
>
>At 14:30 UTC Saturday, after the inertial reference had been established,
>the flight team commanded the spacecraft to begin spinning about the
>earth-line, rather the sun-line, while still maintaining uplink and
>downlink communications via the low gain antennae.  By now, the handover to
>the Madrid Deep-Space Communications Complex had occured (DSS 63 & 65).
>Support from the 70M subnet was released back to the Galileo Project at
>17:00, and by 19:15 UTC, the previously declared state of spacecraft
>emergency was lifted.  Support from TMOD, both the DSN and MGSO services,
>was outstanding throughout.
>
>Throughout the day, attitude performance remained excellent and the flight
>team continued work sending commands to the spacecraft to cleanup all
>remaining effects of the Contingency Mode entry.  Uplink and downlink
>communications have both been restored to the high gain antenna, and the
>sequence to control the spacecraft through periapsis 10 on Sunday morning
>has been successfully loaded.  The flight team is preparing commands to
>playback data recorded onboard the spacecraft during and after the original
>anomaly, and is also making plans for the reinitialization of those
>spacecraft payload instruments which are supporting the aerobraking efforts
>by making measurements of the Martian atmosphere.
>
>Following periapse 10, an aerobraking maneuver is planned a half orbit
>later at apoapsis which will continue to place the spacecraft periapsis
>lower in the Martian atmosphere (pending the results of periapse 10 and
>other data available on the atmosphere).  The payload data subsystem, which
>was powered off along with the instruments upon Contingency Mode entry,
>will be reinitialize on Sunday, while plans are currently under evaluation
>to repower the instruments, themselves, in a 5-hour window after apoapsis
>#10 on Monday (during, roughly, prime shift PDT).
>
>Overall, spacecraft health and performance continue to be excellent and the
>effects of this minor perturbation on the long-term aerobraking and other
>mission objectives are negligible.  With the re-initialization of the
>payload Monday, the project will have fully returned to normal aerobraking
>operations.
>
>Charles Whetsel
>
>Mars Surveyor Ops
>Phone: (818) 393-7758