Posted by tourdemars to Mars Exploration Rovers at August 27, 2008 10:22 AM

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."