Marathon Valley slices downhill from west to east for about 300 yards or meters through the western rim of Endeavour Crater. Opportunity has been investigating rock targets in the western portion of the valley since late July, working its way eastward in a thorough reconnaissance of the area.
The rover's panoramic camera has captured a scene dominated by a summit called "Hinners Point," forming part of the valley's northern edge. The image also shows a portion of the valley floor with swirling reddish zones that have been a target for study. It is online at:
"Our expectation is that Opportunity will be able to remain mobile through the winter," said Mars Exploration Rover Project Manager John Callas of NASA's Jet Propulsion Laboratory, Pasadena, California.
The walkabout is identifying investigation targets in and near the valley floor. Rocks in reddish zones there contain more silica and less iron than most rocks in the area.
"We have detective work to do in Marathon Valley for many months ahead," said Opportunity Deputy Principal Investigator Ray Arvidson, of Washington University in St. Louis. "During the Martian late fall and winter seasons Opportunity will conduct its measurements and traverses on the southern side of the valley. When spring arrives the rover will return to the valley floor for detailed measurements of outcrops that may host the clay minerals."
Endeavour Crater spans about 14 miles (22 kilometers) in diameter. Opportunity has been studying its western rim since 2011. Marathon Valley became a high priority destination after a concentration of clay minerals called smectites was mapped there based on observations by the Compact Reconnaissance Imaging Spectrometer for Mars aboard NASA's Mars Reconnaissance Orbiter. Smectites form under wetter, milder conditions than most rocks at the Opportunity site. Opportunity is investigating relationships among clay-bearing and neighboring deposits for clues about the history of environmental changes.
NASA's Mars Exploration Rover Project landed twin rovers Spirit and Opportunity on Mars in 2004 to begin missions planned to last three months. Both rovers far exceeded those plans. Spirit worked for six years, and Opportunity is still active. Findings about ancient wet environments on Mars have come from both rovers. The project is one element of NASA's ongoing and future Mars missions preparing for a human mission to the planet in the 2030s. JPL, a division of the California Institute of Technology, manages the project for NASA's Science Mission Directorate in Washington.
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Jet Propulsion Laboratory, Pasadena, Calif.