[meteorite-list] Now a Stationary Research Platform, NASA's Mars Rover Spirit Starts a New Chapter in Red Planet Scientific Studies

[Ron Baalke]

Jan. 26, 2010

Dwayne Brown 
Headquarters, Washington 
202-358-1726 
dwayne.c.brown at nasa.gov 

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

RELEASE: 10-024

NOW A STATIONARY RESEARCH PLATFORM, NASA'S MARS ROVER SPIRIT STARTS A 
NEW CHAPTER IN RED PLANET SCIENTIFIC STUDIES

WASHINGTON -- After six years of unprecedented exploration of the Red 
Planet, NASA's Mars Exploration Rover Spirit no longer will be a 
fully mobile robot. NASA has designated the once-roving scientific 
explorer a stationary science platform after efforts during the past 
several months to free it from a sand trap have been unsuccessful. 

The venerable robot's primary task in the next few weeks will be to 
position itself to combat the severe Martian winter. If Spirit 
survives, it will continue conducting significant new science from 
its final location. The rover's mission could continue for several 
months to years. 

"Spirit is not dead; it has just entered another phase of its long 
life," said Doug McCuistion, director of the Mars Exploration Program 
at NASA Headquarters in Washington. "We told the world last year that 
attempts to set the beloved robot free may not be successful. It 
looks like Spirit's current location on Mars will be its final 
resting place." 

Ten months ago, as Spirit was driving south beside the western edge of 
a low plateau called Home Plate, its wheels broke through a crusty 
surface and churned into soft sand hidden underneath. 

After Spirit became embedded, the rover team crafted plans for trying 
to get the six-wheeled vehicle free using its five functioning wheels 
-the sixth wheel quit working in 2006, limiting Spirit's mobility. 
The planning included experiments with a test rover in a sandbox at 
NASA's Jet Propulsion Laboratory in Pasadena, Calif., plus analysis, 
modeling and reviews. In November, another wheel quit working, making 
a difficult situation even worse. 

Recent drives have yielded the best results since Spirit became 
embedded. However, the coming winter mandates a change in strategy. 
It is mid-autumn at the solar-powered robot's home on Mars. Winter 
will begin in May. Solar energy is declining and expected to become 
insufficient to power further driving by mid-February. The rover team 
plans to use those remaining potential drives for improving the 
rover's tilt. Spirit currently tilts slightly toward the south. The 
winter sun stays in the northern sky, so decreasing the southward 
tilt would boost the amount of sunshine on the rover's solar panels. 

"We need to lift the rear of the rover, or the left side of the rover, 
or both," said Ashley Stroupe, a rover driver at JPL. "Lifting the 
rear wheels out of their ruts by driving backward and slightly uphill 
will help. If necessary, we can try to lower the front right of the 
rover by attempting to drop the right-front wheel into a rut or dig 
it into a hole." 

At its current angle, Spirit probably would not have enough power to 
keep communicating with Earth through the Martian winter. Even a few 
degrees of improvement in tilt might make enough difference to enable 
communication every few days. 

"Getting through the winter will all come down to temperature and how 
cold the rover electronics will get," said John Callas, project 
manager at JPL for Spirit and its twin rover, Opportunity. "Every bit 
of energy produced by Spirit's solar arrays will go into keeping the 
rover's critical electronics warm, either by having the electronics 
on or by turning on essential heaters." 

Even in a stationary state, Spirit continues scientific research. 

"There's a class of science we can do only with a stationary vehicle 
that we had put off during the years of driving," said Steve Squyres, 
a researcher at Cornell University and principal investigator for 
Spirit and Opportunity. "Degraded mobility does not mean the mission 
ends abruptly. Instead, it lets us transition to stationary science." 


One stationary experiment Spirit has begun studies tiny wobbles in the 
rotation of Mars to gain insight about the planet's core. This 
requires months of radio-tracking the motion of a point on the 
surface of Mars to calculate long-term motion with an accuracy of a 
few inches. 

"If the final scientific feather in Spirit's cap is determining 
whether the core of Mars is liquid or solid, that would be wonderful 
-- it's so different from the other knowledge we've gained from 
Spirit," said Squyres. 

Tools on Spirit's robotic arm can study variations in the composition 
of nearby soil, which has been affected by water. Stationary science 
also includes watching how wind moves soil particles and monitoring 
the Martian atmosphere. 

Spirit and Opportunity landed on Mars in January 2004. They have been 
exploring for six years, far surpassing their original 90-day 
mission. Opportunity currently is driving toward a large crater 
called Endeavor and continues to make scientific discoveries. It has 
driven approximately 12 miles and returned more than 133,000 images. 

JPL manages the rovers for NASA's Science Mission Directorate in 
Washington. For more information about Spirit and Opportunity, visit: 

http://www.nasa.gov/rovers 
	
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