NASA's Mars Exploration Rover Opportunity will spend the next few months during the coldest part of Martian winter at Greeley Haven, an outcrop of rock at the rim of its next target: The 22km wide Endeavour crater

Opportunity, which landed on Mars eight years ago January 24, has driven a total of 34km. In August, Opportunity arrived at the rim of Endeavour Crater, an ancient 22km wide impact crater. Eroded sections of the crater's rim poke above the flat-lying sediments that Opportunity has driven on since it landed.

Located just south of Mars' equator, the rover has worked through four Martian southern hemisphere winters. Being closer to the equator than its twin rover, Spirit, Opportunity has not needed to stay on a Sun-facing slope during previous winters. Now, however, its solar panels carry a thicker coating of dust than before.

The dust makes it necessary for Opportunity to spend the winter at a Sun-facing site where the rover can tilt its power panels northward about 15° for maximum solar exposure. Greeley Haven provides just the right tilt.

In addition, while Opportunity remains on the slope over winter, it still has some mobility and can investigate Greeley Haven's multiple targets of scientific interest using with the tools on the rover's robotic arm.

Windows into the past

Although they are much eroded, the uplifted segments of Endeavour's rim contain rocks that date back much farther into Martian history than any Opportunity has yet examined.

"Endeavour Crater has given us a whole new mission," remarked Steven Squyres, chief scientist for the Mars Exploration Rover project, describing the prospects for science after Opportunity reached the rim.

Plans for research over the winter at Greeley Haven include a radio-science investigation of the interior of Mars, inspections of mineral compositions and textures on the outcrop, and recording a full-circle, color panorama.

"Greeley Haven provides the proper tilt, as well as a rich variety of potential targets for imaging and compositional and mineralogic studies," says Bell. "We've already found hints of gypsum in the bedrock in this formation, and we know from orbital data that there are clays nearby, too."

Greeley Haven, he says, "looks to be a safe and special place that could yield exciting new discoveries about the watery past of Mars."

Source: Arizona State University