Gemini spacecraft

The Gemini spacecraft was a two-person Earth-orbital vehicle developed to demonstrate the long-duration flight, extravehicular activity, maneuvering, rendezvous, and docking techniques required for Apollo. Twelve numbered flight spacecraft flew from the uncrewed Gemini 1 structural test in 1964 through Gemini 12 in 1966; spacecraft 2 was later modified as Gemini B and became the first U.S. human-spaceflight capsule to fly twice.