41D-3186 (4 Sept 1984) --- Astronaut Robert L. Crippen, 41-G crew commander, prepares to join his six fellow crewmembers for some training in the mockup and integration laboratory at the Johnson Space Center. Astronaut David C. Leestma, 41-G mission specialist, left, will participate in a scheduled extravehicular activity (EVA) on the Challenger's next mission. Today's training is for launch phase procedures.