It was September 26, 1983. Stanislav Petrov, a lieutenant colonel in the Soviet Air Defence Forces, was on duty at Serpukhov-15, a secret bunker outside Moscow. His job: to monitor Oko, the Soviet Union’s early-warning system for nuclear attack. And then to pass along any alerts to his superiors. It was just after midnight when the alarm bells began sounding. One of the system’s satellites had detected that the United States had launched five ballistic missiles. And they were heading toward the USSR. Electronic maps flashed; bells screamed; reports streamed in. A back-lit red screen flashed the word ‘LAUNCH.’”
That the U.S. would be lobbing missiles toward its Soviet counterpart would not, of course, have been out of the question at that particular point in human history. Three weeks earlier, Russians had shot down a South Korean airliner that had wandered into Soviet air space. NATO had responded with a show of military exercises. The Cold War, even in the early ’80s, continued apace; the threat of nuclear engagement still hovered over the stretch of land and sea that fell between Washington and Moscow.
Petrov, however, had a hunch—“a funny feeling in my gut," he would later recall—that the alarm ringing through the bunker was a false one. It was an intuition that was based on common sense: The alarm indicated that only five missiles were headed toward the USSR. Had the U.S. actually been launching a nuclear attack, however, Petrov figured, it would be extensive—much more, certainly, than five. Soviet ground radar, meanwhile, had failed to pick up corroborative evidence of incoming missiles—even after several minutes had elapsed. The larger matter, however, was that Petrov didn’t fully trust the accuracy of the Soviet technology when it came to bomb-detection. He would later describe the alert system as “raw.”