Schroter's valley. View of the snake-like Schroter's valley on the western side of the Moon. This photograph was taken from the lunar-orbiting Apollo 15 Command and Service Module (CSM) on 31 July 1971. The rille (or valley) is thought to have been formed by geological forces early in the Moon's history. Apollo 15 was launched on 26th July 1971, and the Lunar Module touched down on the Moon on 30th July.