Mars rover works its way out of crater

Opportunity ascends after a year; Spirit wakes up from winter hibernation

updated 4:01 p.m. PT, Tues., Aug. 26, 2008 NASA's Opportunity rover is slowly but surely hauling itself out of a vast Martian crater after nearly a year plumbing the interior for secrets of the Red Planet's ancient past.

Opportunity will take the same route it used to enter Victoria Crater on Sept. 11, 2007, after a year of scouting from the rim. Engineers want the rover to make a graceful exit after seeing an electric current spike in its left front wheel — a reminder of a similar spike that occurred when its robotic twin Spirit lost use of a front right wheel in 2006.

"If Opportunity were driving with only five wheels, like Spirit, it probably would never get out of Victoria Crater," said Bill Nelson, a rover mission manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We also know from experience with Spirit that if Opportunity were to lose the use of a wheel after it is out on the level ground, mobility should not be a problem."

The rover drove close to the base of a cliff that makes up part of the crater rim, called "Cape Verde," and snapped detailed images of rock layers reaching 20 feet (6 meters) tall.

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