This series of six images from the Robotic Arm Camera on NASA's Phoenix Mars Lander records the first time that the four spikes of the lander's thermal and electrical conductivity probe were inserted into Martian soil.

The images were taken on July 8, 2008, during the Phoenix mission's 43rd Martian day, or sol, since landing. The insertion visible from the shadows cast on the ground on that sol was a validation test of the procedure. The spikes on the probe are about 1.5 centimeters or half an inch long.

The science team will use the probe tool to assess how easily heat and electricity move through the soil from one spike to another. Such measurements can provide information about frozen or unfrozen water in the soil. The probe is mounted on the "knuckle" of Phoenix's Robotic Arm. It has already been used for assessing water vapor in the atmosphere when it is held above the ground.

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