Scientists will trek into the Arizona desert near Flagstaff this month to study how robots and humans can best interact using spoken language, and to gather data for comparing human and robotic performance. Humans wearing an advanced Mark III spacesuit working alongside an Extra Vehicular Activity Robotic Assistant (ERA) rover will perform tasks representative of future exploration at two sites in the Arizona desert during the first two weeks of September. Exploration tasks will include geophone instrument deployment and field mapping. These tests are a part of NASA strategy to apply advanced technology and cooperative information to improve scientific productivity at a variety of potential locations.