S95-08375 (August 1995) --- Astronaut Kathryn C. Thornton, payload commander for the U.S. Microgravity Laboratory (USML-2) mission, prepares to go underwater in the Johnson Space Center?s (JSC) Weightless Environment Training Facility (WET-F) pool. Thornton was about to rehearse contingency space walk tasks; there is no Extravehicular Activity (EVA) planned for the STS-73 mission.