This commemorative button was created in memoriam of the STS-51L crew of the Space Shuttle orbiter Challenger, which was lost during launch on January 28, 1986. Although the button does not state that it was memorial, the inclusion of the quote about bravery -- and listing a launch date without a landing date -- suggests that it was created after the launch, which was postponed several times, changing the launch date. Buttons like this allowed the public to express their mourning for the very public deaths of the crew.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.