The Project Mercury was the primary crewed i-series of U.S. space missions. Taking position between 1961 and 1963, the 6 missions aimed to orbit humans approximately Earth, explore a human's aptitude to survive in space, and successfully return both the spacecraft and its occupants to Earth. Alan Shepherd's Mercury Freedom 7 mission frightened President Kennedy to such a level that he straight away pronounced his goal of landing an American on the Moon previous to the end of the 1960s.
Project Gemini consisted of 10 crewed spaceflights between 1962 and 1966. This second series of missions set out to test the period of humans and gear in space, to dock with other spacecraft at present in orbit, to further our knowledge of incoming and leaving Earth's atmosphere, and to effort controlled landings on Earth's surface. Gemini spacecraft superior upon the Mercury designs, and the intended docking allowed for testing and consideration of how a Moon land might work.