At the height of the Cold War, the Soviets designed an early-warning radar system meant to track fast-moving threats to increase the chance of reprisal. On September 26, 1983, however, the system, code-named Oko, malfunctioned. At around midnight, Oko’s alarms rang out, alerting the base of one incoming nuclear missile. The screen read, “LAUNCH,” which was not a warning, but an automatic order to prepare for retaliation.
Believing that a U.S. intercontinental ballistic missile (ICBM) was incoming, the base went into a panic. However, some officers on duty were skeptical that the United States would choose to send only one ICBM, knowing that it could not affect the Soviets’ counter-strike capability. Stanislov Petrov, an officer that helped create the code for the early-warning software, also knew that Oko was prone to error. He reset the system, but the alarms persisted.
Rather than following protocol, which entailed alerting superiors up the chain of command, Petrov awaited corroborating evidence. No evidence came, and the alarms soon stopped. Petrov’s actions, or inaction, almost certainly averted a nuclear disaster.
Just 11 days later, NATO forces in Brussels took part in a joint military exercise that simulated a response to a hypothetical Soviet nuclear attack. The exercise was code-named Able Archer 83.
The primary purpose of the exercise was to test the command-and-control procedures for NATO’s nuclear forces in the event of a global crisis. Unlike previous wargames, however, Able Archer 83 featured new elements specifically meant to confuse and disorient the Soviets.
KGB observers alerted Moscow of the unusual activity, and paranoia set in. Working off dubious intelligence that a NATO offensive against the U.S.S.R. could be cloaked under the guise of a military exercise, the Soviets began preparations for a large-scale retaliation. Then Soviet leader Yuri Andropov mobilized entire military divisions, transported nuclear weapons to their launch sites, and scrambled a fleet of bombers carrying nuclear warheads. Military command handed Andropov the nuclear briefcase, known in Russia as the “cheget.”
Lenoard Perroots, a high-ranking intelligence officer for the U.S. Air Force stationed in Europe, observed that the Soviets were responding as though the exercise was real. In what the Foreign Intelligence Advisory Board has called a “fortuitous, if ill informed” decision, Perroots did not reciprocate by raising western asset alert levels. Instead, he waited. The Soviets eventually realized that the exercise was not a surprise attack and aborted their planned response.