NASA's Mars rover Opportunity finished a planned "toe-dip" into an ancient martian impact crater and encountered some slick terrain along the way.
The drive is the robotic explorer's most significant foray after weeks-long dust storms threatened to shut it down.
The robot drove in and then backed out of the crater Tuesday at Duck Bay, the most gradual and rover-accessible entry point into the 2,625-foot-wide (800-meter) crater at Meridiani Planum. Mission managers hope to sample exposed layers of rock along the crater rim for the best glimpse ever into Mar's geological past.
Opportunity radioed home information about the adventure, letting mission managers know that it drove far enough in--about 13 feet (four meters)--to get all six wheels past the crater rim for the first time. It then backed uphill for about 10 feet (three meters) to retreat from the scheduled dip.
In spite of Duck Bay's gentle incline, the rover's wheels encountered excessive slippage, according to a NASA statement. Like a car spinning out on a dirt road, Opportunity's front wheels slipped more than the allowable 40 percent at the edge of the crater.
Mission managers are still determining whether the loose ground is serious enough to prevent Opportunity from carrying out its long-delayed task at the crater.
"We will do a full assessment of what we learned from the drive [Tuesday] and use that information to plan Opportunity's descent into the crater," said John Callas, rover project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
- Top 10 Mars Rovers' Most Amazing Discoveries
- VIDEO: Mars Rover Team Ponders Mission's End
- Complete Coverage of the Mars Rovers