The early NASA missions included the Apollo program, which was a series of spaceflight missions that took place between 1961 and 1972. The Apollo program was the third human spaceflight program carried out by the United States and it achieved the first manned lunar landing in 1969. The Apollo missions were designed to explore the Moon's surface, collect samples, and conduct scientific experiments. The Apollo program also included several unmanned missions that tested the spacecraft and its systems before the first manned mission.