8. Project Gemini put America into a clear lead in space exploration
Project Gemini began in 1961 and continued through 1966, a program in which capsules manned by two astronauts developed the techniques and skills required to fly to the moon. These include rendezvousing with other spacecraft, docking, flying in tandem, and extravehicular activities. The ability to function on flights of longer duration required adapting to the demands of working, eating, and sleeping in zero gravity. Gemini was used to train astronauts in on-the-job circumstances while the Apollo Program worked on the lunar missions. At one point there were discussions about using modified Gemini spacecraft for the lunar mission, but NASA discarded those ideas and went ahead with Apollo.
The expansion of the spacecraft and the need to fly at least two spacecraft at once had led to the expansion of the astronaut corps while Mercury was underway, and though some of the original seven astronauts flew in Gemini, others did not. John Glenn would not return to space until he was in his seventies. The Gemini capsule was designed by a Canadian, with input from the Mercury astronauts, especially Gus Grissom, whose involvement was so heavy that his fellow astronauts began to call the capsule the Gusmobile. During Gemini, Mission Control in Houston became the focus for NASA, and most of the astronauts began living in Houston rather than in Cocoa Beach, near Cape Canaveral.