English: A researcher at the National Aeronautics and Space Administration (NASA) Lewis Research Center examines a small-scale model of the Gemini capsule in the 10- by 10-Foot Supersonic Wind Tunnel test section. Gemini was added to NASA’s manned space program after its predecessor, Mercury, and its antecedent, Apollo, were already established. Gemini was a transitional mission designed provide the astronauts with practice docking with other spacecraft and withstanding durations in space up to two weeks. The program was officially announced on December 7, 1961, but planning began in mid-1959. It was named Gemini after the zodiac twins because of the spacecraft’s two passenger capacity. The Gemini Program was the first program to start at the new Manned Spacecraft Center in Houston, now the Johnson Space Center. Unlike Mercury and Apollo, Lewis had very little involvement with the Gemini Program. This model was tested in the 10- by 10 tunnel for several weeks in September 1962. Lewis began managing the Agena second-stage rocket program shortly after this photograph was taken. Agenas were used to launch a variety of spacecraft and satellites in the 1960s. They were also used on several Gemini missions to provide targets for the astronauts to practice their rendezvous maneuvers. Gemini had two unmanned and ten manned flights in 1965 and 1966. These yielded the first spacewalks, long-duration space missions, first onboard computer, docking with a second spacecraft, and rendezvous maneuvers.