The Artisan prop and model shop of Quantum Mechanix, QMx FX Cinema Arts, was asked to illustrate the history of space flight with models for the film. They constructed fourteen models in total. On their website, there was a picture of the Gemini capsule model. According to the site, this capsule carried two passengers into space. This capsule was the first to allow the passengers to do space walks and to perform orbital maneuvers necessary to achieve docking. The success of this program paved the way ahead for the Apollo program and landing Humans on Luna. 
According to the Star Trek Encyclopedia (4th ed., vol. 1, p. 301), NASA used the Gemini spacecraft for testing "orbital rendezvous, navigation, power systems, and extravehicular activity as part of their research effort to send the first Humans to the moon."