EVA Astronaut Bruce McCandless II, is using a special power tool to conduct an experiment. His feet are anchored in the mobile foot restraints, which are connected to the Remote Manipulator System's (RMS) End Effector. The Shuttle pallet satellite (SPAS-01A) serves as a test subject for McCandless's experiment. The SPAS-01A is located in the center of the open cargo bay. Behind him is the protective cradle for the Westar VI satellite.