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Gemini I and II, the two unmanned missions, which tested the spacecraft's systems and compatibility with the Titan II launch vehicle.What happened in the Gemini project, and why were docking maneuvers so important? Keep reading to find out. A NASA employee came up with the name Gemini, named after the twin constellation. Engineers based their design on the Mercury capsule, but made it larger so that two astronauts could travel together. The new capsule also needed to have more maneuverability than the Mercury spacecraft. The spacecraft would have to be able to dock with another object in space. They had to test how humans handle prolonged space travel. NASA scientists decided they needed to create a project to span between Mercury and Apollo. That way, part of the craft could detach from the rest, land on the moon, launch from the moon into a lunar orbit, and rendezvous and dock with the rest of the spacecraft. After performing some calculations, NASA engineers determined that it made more sense to find a way to enable the craft to dock with other structures in space. The Apollo spacecraft would need to be much larger than the Mercury vehicle. On top of that, the complex trip to the moon and back would require more than one pilot.