Caption:

Astronaut Charles Walker on Space Shuttle Discovery Mission 51-A is conducting the McDonnell Douglas Electrophoresis Operations in Space (EOS) experiment on the flight deck. The EOS experiment was designed to explore ways of processing materials in the weightless conditions of space. The flight deck and the living quarters on the Shuttle are the only pressurised, but still weightless, part of the craft. The Space Shuttle, the world's first partially reusable launch vehicle, first flew on 12th April 1981 and has been used for all America's manned space missions ever since. Mission 51-A was launched on November 8th 1984.