NASA's Gemini space program of the 1960s conducted 10 manned missions between 1965 and 1966 and helped advance space exploration capabilities in preparation for the Apollo moon landings. Gemini missions worked on spacewalking, orbiting, docking with other spacecraft and re-entry capabilities. The Gemini program helped prove that humans could survive and work in space for extended periods, an important step towards the goal of landing astronauts on the Moon.