On the night of September 26, 1983, a natural phenomenon caused the Soviet Oko satellite system to wrongly detect five missile launches from the United States. Lieutenant Colonel Stanislav Petrov, who was on duty at the Serpukhov-15 strategic alert base, determined that the alert was false. He based this judgment on the lack of confirmation from ground-based radar and the unusually low number of detected missiles. His decision prevented a potential nuclear retaliation, an event later confirmed by declassified Soviet military records. This incident occurred just weeks before the Soviet Union shot down Korean Air Lines Flight 007, a civilian aircraft that strayed into Soviet airspace. The Oko system had recently been deployed to monitor American missile bases from space. Its satellites used infrared sensors to detect the heat from a rocket's launch. However, the system had an unforeseen flaw: under specific atmospheric conditions, sunlight reflecting off high-altitude clouds could create a thermal signal nearly identical to that of a missile launch. On September 26, this exact scenario occurred above North Dakota, where American Minuteman missile silos were located. The reflected sunlight was interpreted by the sensors as five missile launches. The alert triggered alarms in the command center, but ground-based radars, which are meant to confirm missile trajectories, found no evidence of an attack. This lack of confirmation troubled Petrov, who reasoned that a real American attack would involve hundreds of missiles launched at once. He decided to dismiss the alert as a false alarm, relying on his instincts and experience rather than the system's automated warning. Petrov's actions remained secret for fifteen years and were only revealed in 1998. Rather than being praised, he was reprimanded for not properly documenting the event in his logbook. The incident highlighted the dangers of over-reliance on automated systems and emphasized the critical role of human judgment in nuclear decision-making. The story inspired the documentary Cold War: The Man Who Saved the World, released in 2014. Petrov passed away in May 2017 in Fryazino, near Moscow, without seeking public recognition for his actions.