S92-49812 (11 Nov 1992) --- Astronauts Gregory J. Harbaugh and Susan J. Helms, mission specialists assigned to fly aboard the Space Shuttle Endeavour for the STS-54 mission, rehearse for the upcoming flight. The two are in the airlock of a trainer at the Johnson Space Center's crew systems laboratory. Harbaugh and Mario Runco Jr., also a mission specialist, have been assigned to perform a four-hour-plus extravehicular activity (EVA). Helms is to assist the pair of spacewalkers during the mission as well as in this training exercise.