It’s one giant explosion for mankind.

At the end of the 1950s — a decade shy of Apollo 11’s successful lunar landing — the US military had the radical idea of detonating a nuclear bomb on the surface of the moon, Air Force documents from 1959 show.

“Nuclear detonations in the vicinity of the moon are considered in this report with scientific information which might be obtained from such explosions … The detonation of a nuclear weapon on or near the moon’s surface has often been suggested,” according to the now unclassified report.

“The military aspect is aided by investigation of space environment, detection of nuclear device testing, and capability of weapons in space.”

It was only initially made public after famed physicist Carl Sagan — who had worked on the project and came up with the nuclear concept — revealed details of its existence when applying for a fellowship at Berkeley’s Miller Institute in 1959.

The discovery had been made by Sagan’s biographer, Keay Davidson, after the late science icon passed in 1996, according to the Guardian.

“In my opinion Sagan breached security in March, 1959,” leading physicist on the project and Sagan’s boss, Leonard Reiffel, wrote in a dated entry for the journal Nature in 2000.

Sagan had been tasked with “mathematically modelling the expansion of an exploding gas/dust cloud rarifying into the space around the Moon,” but had been having “difficulty with the problem,” Reiffel wrote.

“Sagan soon suggested that he should try to see how a nuclear explosion might be used to detect organic molecules on the Moon. I agreed to a brief effort in that direction.”

This “exhaustive” and covert plan out of the Air Force Special Weapons Center at Kirtland Air Force Base, New Mexico — codenamed Project A119 — was in many ways meant to one-up the Soviet Union, which had just sent the world’s first satellite Sputnik into orbit in 1957.

As the US was tailing big time in the space race heading into the 1960s, A119 was meant to be “an exciting response to Sputnik,” historian and nuclear technology expert Alex Wellerstein told the BBC.

“[Other ideas] included shooting down Sputnik, which feels very spiteful. They refer to them as stunts… designed to impress people.”

Such an inspiration was even listed in the many pages of A119 — one which had scientists like Sagan uncover circumstances for the hydrogen bomb’s detonation to be visible on Earth. (They found it doable by manipulating the light and dark sides of the moon on its so-called “terminator” line.)

“The motivation for such a detonation is clearly threefold: scientific, military, and political,” according to the report.

In the Nature article, Reiffel recalled the Air Force’s interest to “fast-track” the feasibility of a detonation — it wouldn’t have had a mushroom cloud because the moon’s lack of atmosphere — prior to May 1958.

“I was told the Air Force was very interested in the possibility of a surprise demonstration explosion, with all its obvious implications for public relations and the Cold War.”

Although NASA ultimately responded to the USSR by launching its own satellite, Explorer 1, in 1958, “they continued this [nuclear] project somewhat seriously, into at least the late 1950s,” added Wellerstein.

“It is a pretty interesting window into the sort of American mindset at that time. This push to compete in a way that creates something very impressive. I think, in this case, impressive and horrifying are a bit too close to each other.”

Eventually, the project had a failure to launch.

“These were serious studies, but they didn’t get any serious funding or attention when they left the space community,” outer space relations expert Bleddyn Bowen told the BBC.

“It was part of the late ’50s, early ’60s space mania before anybody knew exactly what nature the Space Age was going to take.”

Had interested not waned, Reiffel wrote in 2000 that nuking the moon was “certainly technically feasible.”

“Fortunately for the future of lunar science, a one or two horse race to detonate a nuclear explosion never occurred.”