Astronaut Wally Schirra played a harmonica aboard Gemini 6A in December 1965.
Schirra smuggled the small instrument onto the spacecraft and performed “Jingle Bells” with pilot Tom Stafford, who accompanied him on bells. The brief performance became the first musical performance in space.
The harmonica was suitable because it is compact, lightweight, and requires no external power. It produces sound when air passes through free metal reeds, so it can be played by blowing or drawing breath.
The event is sometimes confused with the first musical instrument in space, but earlier missions had carried recorded music and astronauts had sung. Schirra’s live harmonica performance is the famous milestone associated with Gemini 6A. The spacecraft launched on December 15, 1965, and the musical joke was intended as a playful imitation of Santa Claus’s sleigh bells.