NASA takes Mars rover out for inaugural spin

PASADENA, Calif. -- NASA took the rover Opportunity on its first real drive on Mars, a trip across pebbly soil that appears to be unlike anything else seen on the surface of the Red Planet, scientists said Thursday. Opportunity rolled forward about 11 feet on Thursday, leaving it closer to an outcrop of rocks that scientists want to spend days studying. It was the first time the rover had moved since leaving its lander Saturday. Scientists planned for Opportunity to roll 5 more feet today. That should put the slabs of bedrock within reach of the rover's robotic arm, although a little "scoot" may be needed to move Opportunity even closer, said scientist Larry Soderblom of the U.S. Geological Survey.

Scientists skipped plans for the rover to conduct more soil tests on the way to the outcrop, opting instead to reach as quickly as possible a feature on the rocks they have nicknamed "Snout."

Meanwhile, on the far side of the planet, the Spirit rover was expected to return to work Thursday studying a volcanic rock dubbed Adirondack and then strike out for a crater roughly 250 yards away.

NASA said it had successfully reformatted Spirit's "flash memory" and planned to reboot its computer later Thursday before giving it a clean bill of health.

The software problems have stymied its half of the $820 million double mission to find evidence the planet was once a wetter place. Problems with its flash memory have kept the rover parked for two weeks.

On Wednesday, NASA released color-enhanced photographs taken by Opportunity's microscopic imager that show a postage stamp-size patch of soil. Scattered across what is probably volcanic sand are roughly 30 rounded pebbles that intrigue scientists running the mission at JPL.

The roundness of the pebbles can be caused by a handful of processes, ranging from particles rolling around on a sea floor to a meteor impact that hurls molten material into the atmosphere or volcanic action that puts hot ash into the sky, said scientist Hap McSween of the University of Tennessee.

"If you've gotten a sense that we don't quite know what these things are yet, you've got that right," said Steve Squyres, the mission's main scientist.

Once at the outcrop, Opportunity should spend multiple days looking for higher concentrations of hematite, a mineral that can form in water and has been found scattered in the immediate range of its instruments.

A finding of geologic evidence of water would support the possibility that ancient Mars had life. Opportunity and its twin, Spirit, have found intriguing geological data, but scientists remained cautious.

"With respect to extrapolating from a few grains of sand to a story about water on Mars -- little hard to do at this point," Squyres said.

Spirit landed on Mars on Jan. 3, followed three weeks later by Opportunity. They were launched last June and July.

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On the Net: http://marsrovers.jpl.nasa.gov