[meteorite-list] Team Continues Analyzing Spirit Computer Reboots and Amnesia Events

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 21 Apr 2009 09:15:36 -0700 (PDT)
Message-ID: <200904211615.JAA27355_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2009-071

Team Continues Analyzing Spirit Computer Reboots and Amnesia Events
Jet Propulsion Laboratory
April 20, 2009

After three days of completing Earth-commanded activities without
incident last week, NASA's Mars Exploration Rover Spirit had a bout of
temporary amnesia Friday, April 17, and rebooted its computer Saturday,
April 18, behavior similar to events about a week earlier.

Engineers operating Spirit are investigating the reboots and the
possibly unrelated amnesia events, in which Spirit unexpectedly fails to
record data into the type of memory, called flash, where information is
preserved even when power is off. Spirit has had three of these amnesia
events in the past 10 days, plus one on Jan. 25. No causal link has been
determined between the amnesia events and the reboots.

The most recent reboot put Spirit back into an autonomous operations
mode in which the rover keeps itself healthy. Spirit experienced no
problems in this autonomous mode on Sunday. The rover team at NASA's Jet
Propulsion Laboratory, Pasadena, Calif., revised plans today for
regaining Earth control of Spirit's operations and resuming diagnostic
and recovery activities by the rover.

"We are proceeding cautiously, but we are encouraged by knowing that
Spirit is stable in terms of power and thermal conditions and has been
responding to all communication sessions for more than a week now," said
JPL's Sharon Laubach, chief of the rover sequencing team, which develops
and checks each day's set of commands.

During the past week of diagnostic activities, the rover has
successfully moved its high-gain dish antenna and its camera mast, part
of checking whether any mechanical issues with those components may be
related to the reboots, the amnesia events, or the failure to wake up
for three consecutive communication sessions two weeks ago.

Spirit and its twin rover, Opportunity, completed their original
three-month prime missions on Mars in April 2004 and have continued
their scientific investigations on opposite sides of the planet through
multiple mission extensions. Engineers have found ways to cope with
various symptoms of aging on both rovers. The current diagnostic efforts
with Spirit are aimed at either recovering undiminished use of the rover
or, if some capabilities have been diminished, to determine the best way
to keep using the rover.

Laubach said, "For example, if we do determine that we can no longer use
the flash memory reliably, we could design operations around using the
random-access memory." Spirit has 128 megabytes of random-access memory,
or RAM, which can store data as long as the rover is kept awake before
its next downlink communications session.

JPL, a division of the California Institute of Technology in Pasadena,
manages the Mars Exploration Rover project for NASA's Science Mission
Directorate, Washington.

Media contact: Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster at jpl.nasa.gov

2009-071
Received on Tue 21 Apr 2009 12:15:36 PM PDT