Those were the words of Kennedy White House staffer Arthur Schlesinger, talking about the Cuban Missile Crisis of 1962. Many years later, Robert McNamara said in an interview that, after speaking with his Soviet counterpart, they realized that we were “very, very close to nuclear war.”

Here is the story of just how close we were, and of the man who probably prevented it.

Soviet Naval officer Vasili Arkhipov, 34, was one of the three commanders aboard the B-59 submarine near Cuba on Oct. 27. They had received an order from Soviet leadership to stop in the Caribbean short of the American blockade around Cuba. They then dove deep to conceal their presence after being spotted by the Americans and were thus cut off from communication with the surface.

The Americans began dropping non-lethal depth charges in an attempt to get it to surface. But what the Americans didn’t know was that the sub was carrying a ten kiloton nuclear torpedo, and they had permission to use it if necessary without direct instructions from Moscow.

The crew was at depth and incommunicado; moreover, they were sweltering because the air conditioning had stopped working. They thought that they were witnessing the beginning of WWIII! Here is how one crew member described the situation:

“For the last four days, they didn’t even let us come up to the periscope depth … My head is bursting from the stuffy air. … Today three sailors fainted from overheating again … The regeneration of air works poorly, the carbon dioxide content [is] rising, and the electric power reserves are dropping. Those who are free from their shifts, are sitting immobile, staring at one spot. … Temperature in the sections is above 50 [122ºF].”

Two of the three senior officers, including the captain, wanted to launch the torpedo. “We’re gonna blast them now! We will die, but we will sink them all – we will not become the shame of the fleet” exclaimed Captain Valentin Savitsky.

However, it was required that all three senior officers agree on the decision to launch. Two of them did, but Arkhipov dissented. He surmised what the Americans were doing and calmed the captain down.

Arkhipov turned out to be correct. The submarine surfaced and saw that indeed, war had not begun, so turned around and went on its way. The Americans wouldn’t find out until decades later that the submarine had been carrying a nuclear missile.

Arkhipov remained in the Soviet Navy until the 1980s and eventually died at the age of 72 in 1998. 19 years after his death, Arkhipov was honored with the “Future of Life award” by the Future of Life Institute – a US-based organization whose goal is to tackle threats to humanity and whose advisory board includes such luminaries as Elon Musk, the astronomer royal Prof Martin Rees, and actor Morgan Freeman.

“The Future of Life award is a prize awarded for a heroic act that has greatly benefited humankind, done despite personal risk and without being rewarded at the time,” said Max Tegmark, professor of physics at MIT and leader of the Future of Life Institute.

Speaking to Tegmark, Arkhipov’s daughter Elena Andriukova said the family were grateful for the prize, and its recognition of Arkhipov’s actions.

“He always thought that he did what he had to do and never considered his actions as heroism. He acted like a man who knew what kind of disasters can come from radiation,” she said. “He did his part for the future so that everyone can live on our planet.”