With superpower nations stacking up arsenals of nuclear weapons, close-call incidents are unfortunately common and imminent if taken lightly. The 1989 Soviet nuclear false alarm is just one of the dozen incidents that have occurred since the invention of these mass destruction bombs.

Tensions were still high between the Soviet Union and the United States in the 1980s amid the Cold War. Like standing on thin ice, any sudden movement could result in an all-out war, especially after the Soviets had just shot down a stray Korean Airlines passenger plane traveling from New York into its airspace, killing all 269 people on board. The September 1983 tragic misunderstanding pushed both nations further on edge, and the false alarm weeks later could have spelled total disaster if it wasn’t precluded.

What Happened on September 26, 1983?

In the fall of 1983, a Soviet early warning satellite showed that the US had apparently launched five land-based missiles and was heading toward the country. Aside from the incident earlier that month, Soviet forces have been on high alert due to the US military buildup since the late 70s to early 80s, in addition to then-President Ronald Reagan’s anti-Soviet rhetoric.

Shortly after midnight of the 26th, 44-year-old lieutenant colonel Stanislav Petrov was the Soviet Air Defense Forces officer on duty when the early warning, code-named Oko, housed in the Serpukhov-15 bunker near Moscow, went off. Since the satellite was routinely checked with no recent malfunctions, the alarm would have led Stanislav to report an incoming attack according to the procedure immediately.

The system warned that the US had launched five Intercontinental ballistic missiles (ICBMs), and as the on-duty officer, Stanislav had only less than half an hour to decide whether the launch was a real or false alarm.

“Naturally, he began to check all the services in case there had been a software failure. He trusted the visual services the most. After all, they could observe the launch of missiles via satellite,” Dmitry Petrov recounted his father’s account via BBC Reel. “But the visual inspection was impossible because the sun was setting at that moment, and there was the terminator line, the line between day and night, and the satellite was exactly on that borderline, so they simply couldn’t see anything.”

Despite the immense tension between America and the Soviets, Stanislav felt in his gut that a computer error could have triggered the warning system. He also believed that the US was “unlikely to fire only five missiles” if they were to initiate an attack.

“My dad was on the fence because the launch of a single missile couldn’t be a declaration of war,” Dmitry added.