Unlike the Mercury and Apollo spacecraft, which had rocket-powered "escape towers" to pull the capsule away from the booster in an emergency, the two-man Gemini used ejection seats to allow the astronauts to escape. These ejections seats had to function from zero velocity, during an ejection from the spacecraft while sitting on the launch pad, up to 100,000 ft. and a velocity of many times the speed of sound. A rocket motor made by Rocket Power, Inc., of Mesa, Arizona, powered the ejection seat, which was made by Weber Aircraft of Burbank, California.

This ejection seat is a spare that has been installed in the Gemini 3 spacecraft. Gemini 3 carried astronauts Virgil "Gus" Grissom and John Young on the first manned flight of Project Gemini on March 23, 1965. The Gemini spacecraft manufacturer, McDonnell, gave this seat to the Smithsonian in 1970.