[meteorite-list] Spirit Healthy but Computer Reboots Raise Concerns

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 13 Apr 2009 17:32:47 -0700 (PDT)
Message-ID: <200904140032.RAA02155_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2009-066

Spirit Healthy but Computer Reboots Raise Concerns
Jet Propulsion Laboratory
April 13, 2009

Mars Exploration Rover Mission Status Report

The team operating NASA's Mars Exploration Rover Spirit is examining
data received from Spirit in recent days to diagnose why the rover
apparently rebooted its computer at least twice over the April 11-12
weekend.

"While we don't have an explanation yet, we do know that Spirit's
batteries are charged, the solar arrays are producing energy and
temperatures are well within allowable ranges. We have time to respond
carefully and investigate this thoroughly," said John Callas of NASA's
Jet Propulsion Laboratory, Pasadena, Calif., project manager for Spirit
and twin-rover Opportunity. "The rover is in a stable operations state
called automode and taking care of itself. It could stay in this stable
mode for some time if necessary while we diagnose the problem."

Spirit communicated with controllers Friday, Saturday and Sunday, but
some of the communication sessions were irregular. One of the computer
resets apparently coincided in timing with operation of the rover's
high-gain dish antenna.

The rover team has the advantage of multiple communication options.
Spirit can communicate directly with Earth via either the pointable
high-gain antenna or, at a slower data rate, through a low-gain antenna
that does not move. Additionally, communications can be relayed by Mars
orbiters, using the UHF (ultra-high frequency) transceiver, a separate
radio system on the rover.

"To avoid potential problems using the pointable antenna, we might
consider for the time being just communicating by UHF relay or using the
low-gain antenna," Callas said.

Spirit finished its three-month prime mission on Mars five years ago and
has kept operating through multiple mission extensions.

The rover's onboard software has been updated several times to add new
capabilities for the mission, most recently last month. The team is
investigating whether the unexpected behavior in recent days could be
related to the new software, but the same software is operating on
Opportunity without incident.

"We are aware of the reality that we have an aging rover, and there may
be age-related effects here," Callas said.

In the past five weeks, Spirit has made 119 meters (390 feet) of
progress going counterclockwise around a low plateau called "Home Plate"
to get from the place where it spent the past Martian winter on the
northern edge of Home Plate toward destinations of scientific interest
south of the plateau. On March 10, after several attempts to get past
obstacles at the northeastern corner of Home Plate, the rover team
decided to switch from a clockwise route to the counterclockwise one.
Subsequent events have included Spirit's longest one-day drive since the
rover lost use of one of its wheels three years ago, plus detailed
inspection of light-toned soil exposed by the dragging of the inoperable
wheel.

Halfway around Mars, meanwhile, Opportunity has continued progress on a
long-term trek toward Endeavour Crater, a bowl 22 kilometers (14 miles)
in diameter and still about 12 kilometers (12 miles) away. Last week, a
beneficial wind removed some dust from Opportunity's solar array,
resulting in an increase by about 40 percent in the amount of electrical
output from the rover's solar panels. 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

2009-066
Received on Mon 13 Apr 2009 08:32:47 PM PDT