[meteorite-list] Mars Exploration Rover Update - May 20, 2004

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu May 20 20:08:01 2004
Message-ID: <200405210007.RAA21703_at_zagami.jpl.nasa.gov>


SPIRIT UPDATE: Spirit Gets an Unexpected Break. - sol 131-133,
May 20, 2004

Spirit continued its trek to the "Columbia Hills" over the past
four sols, but took an unplanned break on Sols 131 and 132 due
to a software fault on sol 131. That fault left rover planners
with some uncertainty about Spirit's final position and attitude,
so Sol 132 was spent re-establishing that knowledge with panoramic,
navigation and hazard avoidance camera imaging of the rover's
surroundings. The unplanned break did have a silver lining though;
it resulted in fully charged batteries, paving the way for a long
drive on Sol 133. Spirit roved 113 meters (370.7 feet) on Sol 133,
with a record 78-meter (256 feet) autonomous navigation segment.
The previous record for an autonomous navigation drive was 62
meters (203.4 feet) on sol 125. Spirit's odometer now reads 2473
meters (1.53 miles) and it is roughly 780 meters (.5 miles) from the
Columbia Hills and in excellent health.

So what went wrong on sol 131? The flight software team is
uncovering the details, but it appears that the error occurred
within a 3-microsecond window of vulnerability when a "write"
command was attempted to a "write-protected" area of RAM. The
flight software team believes this is an extremely low probability
event, and has not adjusted the planning process to avoid the
miniscule period of vulnerability. Opportunity has the same
vulnerability to the fault.
Received on Thu 20 May 2004 08:07:49 PM PDT

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