Colonel Petrov was at a pivotal point in the decision-making chain. His superiors at the warning-system headquarters reported to the general staff of the Soviet military, which would consult with Mr. Andropov on launching a retaliatory attack.
After five nerve-racking minutes — electronic maps and screens were flashing as he held a phone in one hand and an intercom in the other, trying to absorb streams of incoming information — Colonel Petrov decided that the launch reports were probably a false alarm.
As he later explained, it was a gut decision, at best a “50-50” guess, based on his distrust of the early-warning system and the relative paucity of missiles that were launched.
Colonel Petrov died on May 19 in Fryazino, a Moscow suburb where he lived alone on a pension, but was not widely reported until now. He was 77.
The death was confirmed by his son, Dmitri, according to Karl Schumacher, a political activist who after learning in 1998 of Colonel Petrov’s Cold War role traveled to Russia to meet him and remained a friend. A cause was not announced.
Stanislav Yevgrafovich Petrov was born on Sept. 9, 1939, in Vladivostok, Russia. His father had been a fighter pilot during World War II. He studied at the Kiev Higher Engineering Radio-Technical College of the Soviet Air Force.
After joining the Air Defense Forces, he rose quickly through the ranks; he was assigned to the early-warning system at its inception in the early 1970s.
Historians who have analyzed the episode say that Colonel Petrov’s calm analysis helped to avert catastrophe.
As the computer systems in front of him changed their alert from “launch” to “missile strike,” and insisted that the reliability of the information was at the “highest” level, Colonel Petrov had to figure out what to do.
The estimate was that only 25 minutes would elapse between launch and detonation.
“There was no rule about how long we were allowed to think before we reported a strike,” he later told the BBC. “But we knew that every second of procrastination took away valuable time, that the Soviet Union’s military and political leadership needed to be informed without delay. All I had to do was to reach for the phone; to raise the direct line to our top commanders — but I couldn’t move. I felt like I was sitting on a hot frying pan.”
As the tension in the command center rose — as many as 200 pairs of eyes were trained on Colonel Petrov — he made the decision to report the alert as a system malfunction.
“I had a funny feeling in my gut,” he later told The Washington Post. “I didn’t want to make a mistake. I made a decision, and that was it.”
Colonel Petrov attributed his judgment to both his training and his intuition.
He had been told that a nuclear first strike by the Americans would come in the form of an overwhelming onslaught.
“When people start a war, they don’t start it with only five missiles,” he told The Post. “You can do little damage with just five missiles.”
Moreover, Soviet ground-based radar installations — which search for missiles rising above the horizon — did not detect an attack, although they would not have done so for several minutes after launch.
Colonel Petrov was at first praised for his calm, but in an investigation that followed, he was asked why he had failed to record everything in his logbook. “Because I had a phone in one hand and the intercom in the other, and I don’t have a third hand,” he replied.
He received a reprimand for making mistakes in his logbook.
The false alarm was apparently triggered when the satellite mistook the sun’s reflection off the tops of clouds for a missile launch. The computer program that was supposed to filter out such information had to be rewritten.
Colonel Petrov said the system had been rushed into service in response to the United States’ introduction of a similar system. He said he knew it was not 100 percent reliable.
“We are wiser than the computers,” he said in a 2010 interview with the German magazine Der Spiegel. “We created them.”
The Cold War tensions persisted. In November 1983, NATO carried out Able Archer 83, a big military exercise simulating a coordinated nuclear attack. The exercise, alongside the arrival in Europe of Pershing II nuclear missiles, led some in the Soviet leadership to believe that the United States was using a cover for war; the Soviets placed air units in East Germany and Poland on alert. (Able Archer is the subject of the recent television series “Deutschland ’83.”)
Colonel Petrov retired from the military in 1984. He got a job as a senior engineer at the research institute that had created the early-warning system, but had to retire to care for his wife, Raisa, who had cancer. She died in 1997. In addition to his son, Dmitri, Colonel Petrov is survived by a daughter, Yelena.
Colonel Petrov had largely faded into obscurity — at one point he had been reduced to growing potatoes to feed himself — when the publication in 1998 of the memoir of Gen. Yuriy V. Votintsev, the retired commander of Soviet missile defense, brought to light Colonel Petrov’s role in averting nuclear Armageddon.
The book brought Colonel Petrov a measure of prominence. In 2006, he traveled to the United States to receive an award from the Association of World Citizens, and in 2013 he was awarded the Dresden Peace Prize. He was the subject of a 2014 hybrid documentary-drama, “The Man Who Saved the World.”
Jakob Staberg, the producer of the film, said in a phone interview on Monday he had tried to contact Colonel Petrov by phone and email for the last several weeks, hoping to discuss the film’s Russia release, scheduled for February. He said he did not think much of the delay because Colonel Petrov often traveled.
Colonel Petrov’s role in the film brought him in contact with American celebrities like the journalist Walter Cronkite and the actors Kevin Costner and Robert De Niro, but he did not embrace the spotlight. “I was just at the right place at the right time,” he says in the film.