The robotic arm on NASA's Phoenix Mars Lander enlarged a trench beside a rock called "Headless" during the mission's 115th Martian day (Sept. 20, 2008) in preparation for sliding the rock into the trench. The lander's Surface Stereo Imager took this image later that afternoon, showing the enlarged trench and the rock.

The robotic arm successfully moved the rock two days later.

The Phoenix science team sought to move the rock in order to study the soil and the depth to subsurface ice underneath where the rock had been.

Headless is about the size and shape of a VHS videotape. The trench, called "Neverland," was excavated to about 3 centimeters (1.2 inches) deep near the rock. The ground surface between the rock and the lip of the trench slopes downward about 3 degrees toward the trench.

The left-eye and right-eye images combined into this stereo view were taken at about 4:35 p.m., local solar time on Mars. The scene appears three-dimensional when seen through blue-red glasses. The view is to the north northeast of the lander.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

Photojournal Note: As planned, the Phoenix lander, which landed May 25, 2008 23:53 UTC, ended communications in November 2008, about six months after landing, when its solar panels ceased operating in the dark Martian winter.