Which NASA mission was the first to photograph the far side of the Moon?

NASA’s Lunar Orbiter 1 was the first NASA mission to photograph the far side of the Moon.

Launched on August 10, 1966, Lunar Orbiter 1 entered lunar orbit and returned images of regions that cannot be seen from Earth. The Soviet Luna 3 spacecraft had already photographed the far side in 1959, so Lunar Orbiter 1 was not the first spacecraft of any nation to do so. Its importance was helping NASA survey possible landing sites for the Apollo program.

The mission also produced an iconic image of Earth appearing above the lunar horizon, often called Earthrise, although the better-known Apollo 8 Earthrise photograph came later. Lunar Orbiter 1 completed its mission after transmitting detailed photographs before being deliberately crashed into the Moon in October 1966.