After the end of World War II and the fall of Nazi Germany, two major global powers emerged: Russia in the east, and the United States (along with its NATO allies) in the west.

More than anything, the Cold War was an arms race. Both sides had built up their nuclear arsenals during the war, and both were fearful of having less firepower than the other. Many people thought that an all-out nuclear war was imminent.

During this period, the U.S. military came up with the idea of dropping a nuclear bomb on the moon as a show of force.

Leonard Reiffel was the physicist who headed the project at the U.S. military-backed Armour Research Foundation in the late 1950s.

In 2000, he sat down for an interview with The Observer to tell the story:

“It was clear the main aim of the proposed detonation was a PR exercise and a show of one-upmanship. The Air Force wanted a mushroom cloud so large it would be visible on earth… The explosion would obviously be best on the dark side of the moon and the theory was that if the bomb exploded on the edge of the moon, the mushroom cloud would be illuminated by the sun.”

Reiffel also pointed out that a big influence on the idea was the fact that we were lagging behind in the “Space Race”.

In July of 1955, during the height of the Cold War, the United States announced that it would be launching satellites into space. Not to be outdone, Russia announced their own satellite project four days later. The U.S. lost that leg of the race when Russia launched Sputnik in October of 1957.

Reiffel voiced his concerns as a scientist about the idea of nuking the moon, but they seemed to fall upon deaf ears:

“I made it clear at the time there would be a huge cost to science of destroying a pristine lunar environment, but the US Air Force were mainly concerned about how the nuclear explosion would play on earth.”

In 1958, officers from the Air Force had asked Reiffel to ‘fast-track’ a project to investigate what a nuclear explosion on the moon would look like, and what it’s effects would be.

So he hired none other than a young Carl Sagan to do the calculation of how a nuclear mushroom cloud would expand in the low gravity environment on the moon (Sagan was working on a PhD in astronomy and astrophysics at the time – he completed it in 1960).

Sagan, who pioneered for the study of potential life on other planets, would later become famous for popularizing science in mainstream culture with his show “The Cosmos” (the show was ressurected recently by Seth MacFarlane and Neil DeGrasse Tyson).

Despite the highly classified nature of the project, it was later revealed to his biographer that Sagan actually discussed parts of the project in his application for the prestigious Miller Institute graduate fellowship at Berkley (he got in, of course).

Either way, top-secret project A119: ‘A Study of Lunar Research Flights’, never came to fruition. Reiffel ended his story by saying,

“Thankfully, the thinking changed. I am horrified that such a gesture to sway public opinion was ever considered.”

A spokesman from the Pentagon would neither confirm nor deny the reports. Read the full story from the Guardian here.