Short answers, pulled from the story.
Stanislav Petrov dismissed a computer warning about five incoming intercontinental ballistic missiles as a system error. His decision prevented retaliatory nuclear strikes that would have followed immediately under mutual assured destruction doctrine. The false alarms were caused by sunlight reflecting off high-altitude clouds into Molniya orbit satellites.
Stanislav Petrov served as an officer monitoring the Oko satellite network from the Serpukhov-15 bunker near Moscow. He identified the incoming missile warnings as a malfunction rather than reporting them to superiors. His judgment stopped a potential full-scale nuclear exchange with NATO allies.
Scientists traced the cause to a rare alignment of sunlight reflecting off high-altitude clouds into the satellites' Molniya orbits. This optical illusion triggered sensors to register phantom missile launches by interpreting glare as heat signatures from rocket engines. Ground radar systems failed to detect any corroborative evidence because they could not see beyond the horizon.
Petrov underwent intense questioning by General Yuri Votintsev but received no actual compensation or promotion for saving the country. He was reassigned to a less sensitive post within the military structure and took early retirement following a nervous breakdown. The truth about his actions remained hidden until General Yuri Votintsev revealed the story publicly in 1998.
The truth about the 1983 false alarm remained hidden until 1998 when General Yuri Votintsev became the first person to reveal the story publicly. BBC Moscow correspondent Allan Little conducted an interview with Petrov in October 1998 before he died in 2017. A memorial stone now stands in Warsaw, Poland acknowledging his courage.