On 26 September 1983, during the
Cold War, the Soviet nuclear
early warning system Oko reported the launch of one
intercontinental ballistic missile with four more missiles behind it from the United States. Petrov, suspecting a
false alarm, decided to wait for a confirmation that never came. According to the Permanent Mission of the Russian Federation to the UN, nuclear retaliation requires that multiple sources confirm an attack. precipitating a corresponding nuclear response from the United States. Petrov declared the system's indication 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 alarm had been created by a rare alignment of sunlight on
high-altitude clouds above North Dakota and the
Molniya orbits of the satellites, an error later corrected by cross-referencing a geostationary satellite. Petrov later indicated that the influences on his decision included that he had been told a U.S. strike would be
all-out, so five missiles seemed an illogical start; and that ground radar failed to pick up corroborating evidence, even after minutes of delay. However, in a 2013 interview, Petrov said at the time he was never sure that the alarm was erroneous. He felt that his civilian training helped him make the right decision. He said that his colleagues were all professional soldiers with purely military training and, following instructions, would have reported a missile launch if they had been on his shift. There is some confusion as to precisely what Petrov's military role was in this incident. Petrov, as an individual, was not in a position where he could have single-handedly launched any of the Soviet missile arsenal. His sole duty was to monitor satellite surveillance equipment and report missile attack warnings up the chain of command; top Soviet leadership would have decided whether to launch a retaliatory attack against the West. But Petrov's role was crucial in providing information to make that decision. In contrast, nuclear security scholar Pavel Podvig argues that, while Petrov did the right thing, "there were at least three assessment and decision-making layers above the command center of the army that operated the satellites", so that Petrov's report would not have directly led to a nuclear launch. In addition, he states that, even if the US strike was deemed to be real, the USSR would only have commenced its own strike after actual nuclear explosions on its territory. In 2006, when Petrov was first honored for his actions at the United Nations, the Permanent Mission of the Russian Federation to the United Nations issued a press release contending that a single person could not have started or prevented a nuclear war, stating in part, "Under no circumstances a decision to use nuclear weapons could be made or even considered in the Soviet Union or in the United States on the basis of data from a single source or a system. For this to happen, a confirmation is necessary from several systems: ground-based radars, early warning satellites, intelligence reports, etc." But Blair has said that at that time, the U.S.–Soviet relationship had deteriorated to the point where "the Soviet Union as a system—not just the Kremlin, not just
Andropov, not just the
KGB—but as a system, was geared to expect an attack and to retaliate very quickly to it. It was on hair-trigger alert. It was very nervous and prone to mistakes and accidents. The false alarm that happened on Petrov's watch could not have come at a more dangerous, intense phase in US–Soviet relations."
Aftermath Petrov underwent intense questioning by his superiors about his judgment. Initially, he was praised for his decision. but recalls that he was also reprimanded for improper filing of paperwork because he had not described the incident in the
war diary. Petrov has said that he was neither rewarded nor punished for his actions. According to Petrov, he received no reward because the incident and other bugs found in the missile detection system embarrassed his superiors and the scientists who were responsible for it, so that if he had been officially rewarded, they would have had to be punished. ==Later career==