S73-32854 (10 Sept. 1973) --- Astronaut William R. Pogue, Skylab 4 pilot, uses the Skylab Viewfinder Tracking System (S191 experiment) during a training exercise in the Multiple Docking Adapter (MDA) one-G trainer at Johnson Space Center. In the background is astronaut Gerald P. Carr, seated at the control panel for the Earth Resources Experiments Package (EREP). Carr is Skylab 4 crew commander, and Gibson is science pilot. Photo credit: NASA