By: Clark Edwards - Writer
Posted 9/12/07 - NASA's Opportunity rover has found that the route down into a half-mile-wide (800-meter-wide) crater could be trickier than expected, mission managers reported.
The rover made its first move into Victoria Crater on Tuesday, driving 13 feet (4 meters) down a test route, NASA's Jet Propulsion Laboratory reported in a mission update. That was far enough in to get all six wheels past the crater rim. Then the rover backed uphill for 10 feet (3 meters), NASA said.
On the last step of the drive, the rover's wheels slipped more than 40 percent, triggering an automatic command to stop moving, NASA said. At the end of the day, Opportunity was still stopped with its front pair of wheels within the crater's rim.
"We will do a full assessment of what we learned from the drive ... and use that information to plan Opportunity's descent into the crater," rover project manager John Callas reported in the update.
Eventually, scientists want the rover Opportunity to travel 40 feet (12 meters) down toward a bright band of rocks in the crater. They believe the rocks represent the ancient surface of Mars, and that studying them could shed clues on the planet’s early climate.
The long-awaited descent into the crater — measuring a half-mile (800 meters) across and about 200 to 230 feet (60 to 70 meters) deep — was put on hold in July when a series of sun-blotting dust storms raged in the southern hemisphere. At the height of the storm, Opportunity and its twin, Spirit, went into sleep mode to conserve energy. Spirit is exploring another area far from Opportunity.
Opportunity reached the lip of the crater last month and scouted for possible entry points. The route scientists eventually chose calls for a straight drive down at a 15-degree incline toward the exposed layer of bright rocks.
During a July teleconference, NASA managers admitted the latest mission was risky, but decided to proceed anyway because of the science that could be learned.
The aging but hardy rovers have been exploring Mars for three and a half years — far outlasting their primary, three-month mission.