Flown screw removed from a Manned Maneuvering Unit (MMU) used by either Pinky Nelson or Ox van Hoften on the Challenger STS-41-C mission in April 1984. The white-capped screw measures approximately .75″ long and is sealed with a certificate of authenticity from Martin Marietta Aerospace stating that it was removed from an MMU used on the mission to capture and repair the ‘Solar Max’ satellite, which was the first time man had repaired a satellite in space. In fine condition. Accompanied by an official Martin Marietta photo of Nelson flying in an MMU as he prepares to dock with the malfunctioning satellite. From the collection of aerospace memorabilia specialist Ken Havekotte.