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Date: Fri, 17 Mar 2006 16:35:22 -0800
From: NASA Jet Propulsion Laboratory <[EMAIL PROTECTED]>
To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
Subject: Mars Rovers Get New Manager During Challenging Period

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Guy Webster (818) 354-6278
Jet Propulsion Laboratory, Pasadena, Calif.

Dwayne Brown/Erica Hupp         (202) 358-1726/1237
NASA Headquarters, Washington

News Release: 2006-039                                          March 17, 2006

Mars Rovers Get New Manager During Challenging Period

NASA's long-lived Mars rovers demand lots of care as they age and the Martian 
winter approaches.

Dr. John Callas, newly named project manager for NASA's Mars Exploration Rover 
mission, is
coordinating the work to meet these challenges. He is a scientist at NASA's Jet 
Propulsion Laboratory
in Pasadena, Calif. He was named project manager after earlier roles as science 
manager and deputy
project manager for the Spirit and Opportunity rovers.

"It continues to be an exciting adventure with each day like a whole new mission," 
Callas said. "Even
though the rovers are well past their original design life, they still have 
plenty of capability to conduct
outstanding science on Mars. The JPL operations team and the remote science 
team working on the
project are the best in the solar system at what they do. It is a pleasure and 
a privilege to lead such an
outstanding team and great mission."

One of Spirit's six wheels has stopped working. Dragging that wheel, the 
solar-powered rover must
reach a slope where it can catch enough sunshine to continue operating during 
the Martian winter.
The period of minimum sunshine is more than 100 days away, but Spirit gets only 
enough power for
about one hour per day of driving on flat ground. And the supply is dropping 
fast.

Spirit's right-front wheel became a concern once before, when it began drawing 
unusually high
current five months after the January 2004 landing on Mars. Driving Spirit 
backwards redistributed
lubricant and returned the wheel to normal operation. This week, during the 
779th Martian day of
what was originally planned as a 90-Martian-day mission, the motor that rotates 
that wheel stopped
working.

"It is not drawing any current at all," said JPL's Jacob Matijevic, rover 
engineering team chief. One
possibility engineers are considering is that the motor's brushes, contacts 
that deliver power to the
rotating part of the motor, have lost contact. The motors that rotate Spirit's 
wheels have revolved
more than 13 million times, far more than called for in the rovers' design.

Spirit's solar panels have been generating about 350 watt-hours of electricity 
daily for the past week.
That is down about 15 percent since February and less than one-half of their 
output during the
Martian summer.

The best spot for Spirit is the north-facing side of "McCool Hill," where it 
could spend the southern-
hemisphere winter tilted toward the sun. Spirit finished studying a bright feature called 
"Home Plate"
last week and is driving from there toward the hill. It has approximately 120 
meters (about 390 feet)
to go. Driving backwards with the right-front wheel dragging, the rover needs 
to stop and check
frequently that the problem wheel has not snagged on anything and caused other 
wheels to slip
excessively.  Expected progress is around 12 meters (40 feet) per day under 
current conditions.

Opportunity is closer to the equator, so does not need to winter on a slope 
like Spirit. Opportunity
spent most of the past four months at "Erebus Crater."  It examined layered 
outcrops, while the rover
team determined and tested a strategy for dealing with degraded performance by 
a motor in the
shoulder of its robotic arm. Opportunity left Erebus this week and is on a 2 
kilometer (1.2 mile)
journey to a giant crater called "Victoria."

Callas has worked on the Mars rovers' mission since 2000 and five other Mars 
missions since joining
JPL in 1987. He succeeds Jim Erickson, who switched to a leadership role with 
NASA's Mars
Reconnaissance Orbiter. Callas grew up near Boston and graduated from Tufts 
University, Medford,
Mass. He earned his doctorate in physics from Brown University, Providence, R.I.

JPL, a division of the California Institute of Technology, Pasadena, manages 
the Mars Exploration
Rover and Mars Reconnaissance Orbiter projects for NASA's Science Mission 
Directorate.

For images and information about the rovers on the Web, visit:

http://www.nasa.gov/rovers

For information about NASA and agency programs on the Web, visit:

http://www.nasa.gov/home

-end-





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