NASA's Mars Exploration Rover Opportunity used its front hazard-avoidance camera to take this picture showing the rover's arm extended toward a light-toned rock, "Tisdale 2," during the 2,695th Martian day, or sol, of the rover's work on Mars (Aug. 23, 2011). Tisdale 2 is about 12 inches (30 centimeters) tall.

The rover used two instruments on the robotic arm, the microscopic imager and the alpha particle X-ray spectrometer, to examine Tisdale 2. In this image, the turret at the end of the arm is positioned so that the microscopic imager is facing the rock.

Tisdale 2 and other rocks on the ground beyond it were apparently ejected by the impact that excavated a 66-foot-wide (20-meter-wide) crater, called "Odyssey," which is nearby to the left (north) of this scene. Odyssey and these rocks are on a low ridge called "Cape York," which is a segment of the western rim of Endeavour crater. Endeavour is about 14 miles (22 kilometers) in diameter. Portions of the interior and eastern rim of Endeavour are visible near the top of this image.