Astronauts George D. Nelson (nearest camera) and Thomas D. Akers, suited in extravehicular mobility units (EMUs), work with the Gamma Ray Observatory (GRO) mockup in JSC's Weightless Environment Training Facility (WETF) Bldg 29. Having achieved neutral buoyancy in the 25-ft deep pool, Nelson and Akers were verifying changes in handrail and portable foot restraint (PRF) locations made during 1985 training. They also practiced contingency extravehicular activity (EVA) or unplanned GRO solar array (SA) and high gain antenna (HGA) deployment, refueling and module changeouts.
