NASA Mars Rover Churns Up Questions With Sulfur-Rich Soil

Some bright Martian soil containing lots of sulfur and a trace of water intrigues researchers who are studying information provided by NASA's Spirit rover.

"This material could have been left behind by water that dissolved these minerals underground, then came to the surface and evaporated, or it could be a volcanic deposit formed around ancient gas vents," said Dr. Ray Arvidson of Washington University, St. Louis. He is the deputy principal investigator for NASA's twin Mars rovers, Spirit and Opportunity.

Determining which of those two hypotheses is correct would strengthen understanding of the environmental history of the Columbia Hills region that Spirit has been exploring since a few months after landing on Mars in January 2004. However, investigating the bright soil presents a challenge for the rover team, because the loose material could entrap the rover.

The bright white and yellow material was hidden under a layer of normal-looking soil until Spirit's wheels churned it up while the rover was struggling to cross a patch of unexpectedly soft soil nearly a year ago. The right front wheel had stopped working a week earlier. Controllers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., were trying to maneuver the rover backwards, dragging that wheel, to the north slope of a hill in order to spend the southern-hemisphere winter with solar panels tilted toward the sun. ...

•	NASA Mars Rover Churns Up Questions With Sulfur-Rich Soil ScienceDaily.com, Thursday, March 15, 2007 Byline: Space Daily staff

•	Did a giant impact create the two faces of Mars? NewScientist.com (UK), Thursday, March 15, 2007 Byline: NO BYLINE

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