NASA's Mars Exploration Rover Opportunity recorded this view of a crater informally named 'Freedom 7' shortly before the 50th anniversary of the first American in space: astronaut Alan Shepard's flight in the Freedom 7 spacecraft.

NASA's Mars Exploration Rover Opportunity recorded this view of a crater informally named "Freedom 7" shortly before the 50th anniversary of the first American in space: astronaut Alan Shepard's flight in the Freedom 7 spacecraft.

The image combines two frames that Opportunity took with its navigation camera during the 2,585th Martian day, or sol, of the rover's work on Mars (May 2, 2011). Shepard's suborbital flight lasted 15 minutes on May 5, 1961.

The crater is about 25 meters (82 feet) in diameter. It is the largest of a cluster of about eight craters all formed just after an impactor broke apart in the Martian atmosphere.

By taking advantage of seeing many craters of diverse ages during drives between major destinations, the Opportunity mission is documenting how impact craters change with time. The cluster that includes Freedom 7 crater formed after sand ripples in the area last migrated, which is estimated to be about 200,000 years ago.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for the NASA Science Mission Directorate, Washington.

View all Images