Declassified documents show the US discussed detonating a nuclear weapon on the Moon, and using it as a listening post.
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 US Air Defence Support Program currently operates multiple satellites around Earth to watch for any warning signs of weapons or spacecraft being launched.
The report was released to mark the 45th anniversary of Neil Armstrong's historic moonwalk.
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.
The documents show the military also attempted to investigate the effects of detonating a nuclear weapon on the Moon.
The potential effects of nuclear radiation on alien life forms were discussed in the document, but a detonation never took place.
