Stanislav Petrov incident

On September 26, 1983, Stanislav Petrov, an Air Defence lieutenant colonel, was the officer on duty at the Serpukhov-15 bunker near Moscow which housed the command center of the Soviet early warning system, code-named Oko[5]. Petrov's responsibilities included observing the satellite early warning network and notifying his superiors of any impending nuclear missile attack against the Soviet Union. If notification was received from the early warning systems that inbound missiles had been detected, the Soviet Union's strategy was an immediate nuclear counter-attack against the United States (launch on warning), specified in the doctrine of mutual assured destruction.[1]

Shortly after midnight, the bunker's computers reported that an intercontinental ballistic missile was heading toward the Soviet Union from the US.[6] Petrov considered the detection a computer error, since a United States first-strike nuclear attack would be likely to involve hundreds of simultaneous missile launches, in order to disable any Soviet means for a counterattack. Furthermore, the satellite system's reliability had been questioned in the past.[7] Petrov dismissed the warning as a false alarm, though accounts of the event differ as to whether he notified his superiors[1] or not[6] after he concluded that the computer detections were false and that no missile had been launched. Later, the computers identified four additional missiles in the air, all directed towards the Soviet Union. Petrov again suspected that the computer system was malfunctioning, despite having no other source of information to confirm his suspicions. The Soviet Union's land radar was incapable of detecting missiles beyond the horizon[7], and waiting for it to positively identify the threat would limit the Soviet Union's response time to minutes.

Had Petrov reported incoming American missiles, his superiors might have launched an assault against the United States, precipitating a corresponding nuclear response from the United States. Petrov declared the system's indications a false alarm. Later, it was apparent that he was right: no missiles were approaching and the computer detection system was malfunctioning. It was subsequently determined that the false alarms had been created by a rare alignment of sunlight on high-altitude clouds and the satellites' Molniya orbits, an error later corrected with cross-reference to a geostationary satellite.[8]

Petrov later indicated the influences in this decision included: that he had been told a US strike would be all-out, so that five missiles seemed an illogical start;[1] that the launch detection system was new and, in his view, not yet wholly trustworthy; and that ground radars were still failing to pick up any corroborative evidence, even after minutes of delay.[7]