NASA announced December 7, 1961, a plan to create a new manned space flight program by development of a two-man spacecraft. The program was officially designated Gemini on January 3, 1962. It was named after the third constellation in the zodiac. The program had 11 flights starting with Gemini 3 and only one mission failure.

The spacecraft was an enlargement of its predecessor, the Mercury capsule--5.8m (19 ft) long, 3m (10 ft) in diameter, and about 3810 kilograms (8400 pounds) in weight. Many new engineering changes simplified maintenance and made it more maneuverable. The Titan II rocket, more powerful than the Redstone, rocketed the larger spacecraft into orbit.

Sometimes referred to as Gemini-Titan referring to the craft and its launch vehicle, each flight was distinguished by a Roman numeral. Only the first capsule was nicknamed. Command Pilot Virgil Grissom called it the “Molly Brown” in reference to his Mercury spacecraft that sank.