[meteorite-list] Mars Rovers Get New Manager During Challenging Period

[Ron Baalke]

March 17, 2006

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

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

RELEASE: 06-101

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.

John Callas, newly named project manager for NASA's Mars Exploration 
Rover missions, is coordinating the work to meet these challenges. He 
is a scientist at NASA's Jet Propulsion Laboratory (JPL) 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 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 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 its 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 toward the hill. It has approximately 120 
meters (about 390 feet) to go. Expected progress is approximately 12 
meters (40 feet) per day. 

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' operation since 2000 and five 
other Martian 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/mars  

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

http://www.nasa.gov/home 

	
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