ملف:SIMULATION (EXTRAVEHICULAR ACTIVITY EVA) - STS-23 (51D) - JSC.jpg

S85-30878 (15 April 1985) --- Astronaut Jerry L. Ross, left, and Astronaut candidate Mark C. Lee rehearse the deployment of two specially designed flyswatter like tools on the end of the orbiter's remote manipulator system (RMS) arm. Their "dry" run of a planned Discovery STS 51-D extravehicular activity (EVA) is actually not so dry, since it is held in a 25 ft. deep pool, part of the Johnson Space Center's (JSC) weightless environment test facility (WET-F). Astronauts Jeffrey A. Hoffman and S. David Griggs, two 51-D mission specialists, have been assigned the task of April 16's EVA. A rendezvous with the troubled Syncom IV (LEASAT) satellite has been scheduled for the day after the EVA, and an attempt will be made by the arm to trip an important lever on the troubled communications satellite.