Astronaut George Nelson (top left) attempting to dock with the U.S. Solar Maximum Mission (SMM) satellite during an in-orbit repair mission by the crew of Space Shuttle "Challenger" in April 1984. The SMM satellite is specially equipped to observe the Sun in white light through the gamma-ray region of the electromagnetic spectrum and to monitor its total energy output. The satellite was launched February 14, 1980.

By courtesy of the National Aeronautics and Space Administration