Apollo 8 was the first crewed spacecraft to orbit the Moon, in December 1968.
Launched on December 21, 1968, Apollo 8 carried Frank Borman, James Lovell, and William Anders. The crew entered lunar orbit on December 24 and completed ten orbits before returning safely to Earth.
The mission was originally planned as a lower-Earth-orbit test, but NASA changed its objectives after rapid progress in the space race and concerns about the Soviet Union reaching the Moon first. Apollo 8 tested the Saturn V rocket, navigation, communications, and lunar-orbit operations.
It did not land astronauts on the Moon; that achievement came with Apollo 11 in July 1969. Apollo 8 is also remembered for the famous Earthrise photograph, taken by Anders while orbiting the Moon.