S90-48372 (29-31 July 1990) --- Mission specialist astronaut candidate Susan J. Helms simulates a parachute jump during a survival training course at Vance Air Force Base. She is one of 23 astronaut candidates from the Johnson Space Center who have joined military personnel for the special three-day training course. The course is designed to prepare the trainees for proper survival measures to take in the event of an emergency aboard the T-38 jet trainer aircraft they will frequently use once they become full-fledged astronauts.