[meteorite-list] Alternatives Have Begun in Bid to Hear from Spirit

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 22 Mar 2011 13:43:22 -0700 (PDT)
Message-ID: <201103222043.p2MKhMto021180_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2011-087

Alternatives Have Begun in Bid to Hear from Spirit
Jet Propulsion Laboratory
March 18, 2011

PASADENA, Calif. -- Hopes for reviving NASA's Spirit Mars rover dimmed
further with passage last week of the point at which the rover's locale
received its maximum sunshine for the Martian year.

The rover team has tried to contact Spirit for months with strategies
based on the possibility that increasing energy availability might wake
the rover from hibernation. The team has now switched to communication
strategies designed to address more than one problem on the rover. If no
signal is heard from Spirit in the next month or two, the team at NASA's
Jet Propulsion Laboratory, Pasadena, Calif., will shift to single-rover
operations, continuing to operate Spirit's active twin, Opportunity.

"The commands we are sending starting this week should work in a
multiple-fault scenario where Spirit's main transmitter is no longer
working and the mission clock has lost track of time or drifted
significantly," said JPL's John Callas, project manager for Spirit and
Opportunity.

Spirit landed on Mars Jan. 4, 2004 Universal Time (Jan. 3, Pacific Time)
for a mission designed to last for three months. After accomplishing its
prime-mission goals, Spirit worked for more than five years in
bonus-time extended missions.

Spirit has not communicated since March 22, 2010. Power output from its
solar array had been waning prior to that, and the rover had been
expected to go into a low-power hibernation mode. With drive motors on
two of its six wheels no longer working, Spirit had been unable in
preceding months to maneuver much in its sand-trap location. The rover
could not get to a favorable tilt for its solar panels as Martian winter
approached.

During the Martian winter with most heaters turned off, Spirit
experienced colder internal temperatures than in any of its three
previous winters on Mars. The cold could have damaged any of several
electronic components that, if damaged, would prevent reestablishing
communication with Spirit.

However, attempts to regain contact have continued for more than eight
months in the possibility that the seasonal increase in solar energy
available at Spirit's location would revive the rover. NASA's Deep Space
Network of antennas in California, Spain and Australia has been
listening for Spirit daily. The rover team has also sent commands to
elicit a response from the rover even if the rover has lost track of
time, or if its receiver has degraded in frequency response.

The available solar energy at Spirit's site was estimated to peak on
March 10. Revised commanding began March 15, including instructions for
the rover to be receptive over UHF relay to hailing from the Mars
orbiters for extended periods of time and to use a backup transmitter on
the rover.

Spirit and Opportunity both have made important discoveries about wet
environments on ancient Mars that may have been favorable for supporting
microbial life. Opportunity landed three weeks after Spirit.

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

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Guy.Webster at jpl.nasa.gov

2011-087
Received on Tue 22 Mar 2011 04:43:22 PM PDT