Stuart A. Roosa, backup crew command module pilot for Apollo 17, participates in extra vehicular activity simulation training aboard a U.S. Air Force KC-135 aircraft. A mock-up of the Scientific Instrument Module (SIM) bay of the Apollo 17 service module is used in the exercise. Here, Roosa simulates retrieving the film cassette of the mapping camera from the SIM bay. The KC-135 "Vomit Comet" can simulate zero- gravity or partial- gravity conditions by diving and climbing in a series of parabolic arcs in the sky.
