1. Another U-2 Spy Plane Incident

On October 27, 1962, just as the Cuban Missile Crisis was reaching its boiling point, an American U-2 spy plane took off from Alaska en route to a routine reconnaissance mission near the North Pole. Pilot Charles Maultsby was supposed to use celestial navigation to find his way, but halfway through the trip his view of the night sky became hopelessly obscured by the glow of the aurora borealis, or “northern lights.” With no visual markers to guide him, Maultsby soon drifted far off course and inadvertently crossed the border into the Soviet Union.

Because the situation in Cuba still rested on a knife-edge, Maultsby’s accidental detour carried possibly catastrophic consequences. Worried the U-2 could be a nuclear bomber, the Soviets scrambled several MiG fighter jets and sent them on a course to destroy the intruding aircraft. The Air Force responded by dispatching two F-102 fighters armed with nuclear-tipped missiles to shepherd Maultsby back to Alaska. Any confrontation between the two groups of aircraft could have potentially ended in all-out war, but Maultsby managed to glide his U-2—which had long since run out of fuel—out of Soviet airspace before he could be intercepted. Having averted disaster on two fronts, President John F. Kennedy and Soviet leader Nikita Khrushchev would find a peaceful resolution to the Cuban Missile Crisis the following day.

2. The B-59 Submarine Incident

That same day, a minor incident aboard a Soviet submarine might stand as the closest the world has ever come to nuclear war. On October 27, 1962, at the height of the Cuban Missile Crisis, the American destroyer USS Beale began dropping depth charges on the nuclear-armed Soviet submarine B-59, which was lurking near the U.S. blockade line around Cuba. The charges were non-lethal warning shots intended to force B-59 to the surface, but the submarine’s captain mistook them for live explosives. Convinced he was witnessing the opening salvo of World War III, the captain angrily ordered his men to arm the sub’s lone nuclear-tipped torpedo and prepare for attack.

The misunderstanding could have resulted in disaster if not for a contingency measure that required all three of the submarine’s senior officers to sign off on a nuclear launch. The Soviet captain was in favor, but Vasili Arkhipov, B-59’s second in command, refused to give his consent. After calming the captain down, Arkhipov coolly convinced his fellow officers to bring B-59 to the surface and request new orders from Moscow. The submarine eventually returned to Russia without incident, but it was over 40 years before a full account of Arkhipov’s life-saving decision finally came to light.

3. The 1979 NORAD Computer Glitch

The NORAD entrance at Cheyenne Mountain.
Lyn Alweis/The Denver Post via Getty Images
The entrance to NORAD at Cheyenne Mountain in Colorado, circa early 1980s.

By the late 1970s, both the United States and the Soviets relied on computer systems to detect possible nuclear attacks. But while the new technology was more sophisticated, it also came with a fresh set of risks in the form of false alarms and glitches. Perhaps the most famous of these errors occurred at Colorado’s North American Aerospace Defense Command, or NORAD. On the morning of November 9, 1979, technicians at the site received an urgent alert that the Soviets had launched a barrage of missiles at North America. Convinced a nuclear attack was imminent, the U.S. air defense program scrambled 10 interceptor fighter planes, ordered the president’s “doomsday plane” to take off, and warned launch control to prepare its missiles for a retaliatory attack.

The panic soon subsided after NORAD consulted its satellite data and realized the nuclear warning was little more than a false alarm. Upon further inspection, they discovered that a technician had accidentally run a training program simulating a Soviet attack on the United States. The incident sent shock waves through the international community—Soviet leader Leonid Brezhnev even wrote President Jimmy Carter a letter noting the “tremendous danger” caused by the error—but it was not the last time a computer issue led to a nuclear scare. Computer chip failures would later lead to three more false alarms at NORAD in the following year.

4. The 1983 Nuclear False Alarm

On September 26, 1983, Lt. Colonel Stanislav Petrov was in command at Serpukhov-15, a bunker where the Soviets monitored their satellite-based detection systems. Shortly after midnight, panic broke out when an alarm sounded signaling that the United States had fired five Intercontinental Ballistic Missiles, or ICBMs, toward Russia. The warning was a false alarm—one of the satellites had misinterpreted the glint of sunlight off clouds near Montana as a missile launch—but to the Soviets, it appeared the United States had started a nuclear war.

Protocol demanded that Serpukhov-15 report any signs of a missile launch to the Soviet high command, but Petrov had a hunch the warning was an error. He knew the new satellite system was mistake-prone, and he also reasoned that any nuclear strike by the Americans would come in the form of hundreds of missiles, not just five. With only minutes to make a decision, Petrov chose to ignore the blaring warning alarms and reported the launch as a false alarm—a move that may have averted a nuclear holocaust. The incident remained classified until after the Cold War ended, but Petrov later received several humanitarian awards for his extraordinary actions, and was even honored by the United Nations.

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5. The Able Archer 83 Exercise

Although it was not widely known at the time, declassified government documents have since revealed that a November 1983 NATO war game nearly saw the United States and the Soviet Union come to blows. The source of the misunderstanding was an exercise known as Able Archer 83, which was supposed to simulate how a conventional attack on Europe by the Soviet Union could eventually be met by a U.S. nuclear strike. Such simulations were not uncommon during the Cold War, but the Able Archer mission differed from the usual protocol in both its scope and realism. In preparation for the war game, the United States airlifted 19,000 troops to Europe, changed its alert status to DEFCON 1 and moved certain commands to alternate locations—all steps that typically would only be taken in times of war.

For the Soviets, these maneuvers perfectly matched their own predictions for how the Americans would set the table for a nuclear offensive. While they knew a war game was taking place, they were also wary that it could be a ruse to cover up preparations for a real world attack. Unbeknownst to the Americans, the Soviets had soon gone into high alert and readied their nuclear arsenal, with some units in East Germany and Poland even preparing their fighter jets for takeoff. They remained poised for a counterstrike until November 11, when the Able Archer exercise ended without incident. Only later did NATO and the United States realize that their realistic simulation of World War III had very nearly led to the real thing.