The United States military once made plans to build a surveillance station on the moon, newly declassified documents reveal.

A 100-page document compiled in 1959 details Project Horizon, a plan to install a moon-to-Earth surveillance system used to "facilitate communications with and observation of the Earth".

The declassified documents also reveal that the military attempted to investigate the effects of detonating a nuclear weapon on and in the vicinity of the moon.

It also detailed a plan to build a moon-based weapons system that would have allowed the military to launch attacks from the moon towards targets on Earth.