The primary purpose of the Mars Volatiles And Climate Surveyor (MVACS) Robotic Arm is to support the other MVACS science instruments by digging trenches in the Martian soil; acquiring and dumping soil samples into the Thermal Evolved Gas Analyzer; positioning the Soil Temperature Probe in the soil; positioning the Robotic Arm Air Temperature Sensor at various heights above the surface, and positioning the Robotic Arm Camera for taking images of the surface, trench, soil samples, magnetic targets, and other objects of scientific interest within its workspace. In addition to data collected from the Robotic Arm sensors during science support operations, the Robotic Arm will perform experiments along with the other science instruments to yield additional information on Martian soil mechanics in the vicinity of the lander. The experiments include periodic imaging of dumped soil piles, surface scraping and soil chopping experiments, compaction tests, insertion of the various end-effector tools into the soil, and trench cave-in tests. Data from the soil mechanics experiments will yield information on Martian soil properties such as angle of repose, cohesion, bearing strength, and grain size distribution. ¿ 2001 The American Geophysical Union.