This lapel pin belonged to Space Shuttle astronaut David M. Brown. He flew on Shuttle mission STS-107 (2003) and died when Columbia disintegrated during reentry. Before he joined NASA, Brown earned a medical degree, served in the US Navy, and became flight surgeon and naval aviator. He collected pins such as this during his career as an astronaut, which took him on frequent trips to Russia.
After the shuttle mission ended in tragedy, his family gave this and other personal items to the Museum, which he had enjoyed visiting in his youth.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.