Please click the icon to follow us on Facebook.the correct identification of an American First Strike by a Soviet orbital Missile Early Warning System was transmitted to the Serpukhov-15 bunker near Moscow where it was dismissed as a computer error by duty officer Lieutenant Colonel Stanislav Petrov.

NATO had been set to launch a ten-day command post exercise known as "Able Archer 83" which was to incorporate a new, unique format of coded communication, radio silences, participation by heads of state, and a simulated DEFCON 1 nuclear alert.

On the eve of the exercise, the Soviet Union committed an unmistakeable act of war by shooting down South Korean civilian airliner Korean Air Lines Flight 007 over the Sea of Japan, killing all 269 passengers and crew aboard including Lawrence McDonald, a sitting member of the United States Congress.

As a result, President Reagan decided to use the exercise to obscure preparations for a genuine nuclear first strike. Ironically, KGB director Yuri Andropov had anticipated this move by creating Operation RYAN, a Soviet intelligence operation that monitored the likelihood of an American-led nuclear first strike against the Soviet Union. However the Ryan Planners had failed to anticipate that a duty officer would disregard two early warnings and compound the error by failing to report the matter to his superiors.