Moon by the Soviet Union's Luna 2, an unmanned spacecraft. The United States' NASA Apollo program achieved the only manned lunar missions to date, beginning with the first manned orbital mission by Apollo 8 in 1968, and six manned landings between 1969 and 1972, with the first being Apollo 11. These missions returned lunar rocks which have been used to develop a geological understanding of the Moon's origin, internal structure, and the Moon's later history. Since the Apollo 17 mission in 1972, the Moon has been visited only by unmanned spacecraft. Both the Moon's natural prominence in the earthly sky and
Colonization of the Moon about four months only but covered a third more distance. 1974 saw the end of the Soviet Moonshot, two years after the last American manned landing. Besides the manned landings, an abandoned Soviet moon program included building the moonbase "Zvezda", which was the first detailed project with developed mockups of expedition vehicles and surface modules. In the decades following, interest in exploring the Moon faded considerably, and only a few dedicated enthusiasts supported a return. However, evidence of lunar ice at the poles gathered by NASA's Clementine (1994) and Lunar Prospector (1998) missions rekindled some discussion, as did the potential