This Apollo command module tie tac is part of a commemorative set that includes a matching set of cufflinks belonging to NASA astronaut Michael Collins. On July 20, 1969, astronauts Neil Armstrong and Edwin "Buzz" Aldrin became the first human beings to walk on the lunar surface while Collins orbited the Moon in the Apollo 11 command module.
When Collins became the director of the National Air and Space Museum, he loaned this tie tac to the Museum for display in the "Apollo to the Moon" gallery. He gave the cufflinks and tie tac to the National Collection as permanent donations in 1984.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.