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What was the 1983 Soviet Nuclear False Alarm Incident?

Introduction On 26 September 1983, during the Cold War, the Soviet nuclear early warning system Oko reported the launch of one intercontinental ballistic missile with four more missiles behind it, from the United States. These missile attack warnings were suspected to be false alarms by Stanislav Petrov, an engineer of the Soviet Air Defence Forces… Read More

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What is the Purpose of a Permissive Action Link?

Introduction A permissive action link (PAL) is an access control security device for nuclear weapons. Its purpose is to prevent unauthorised arming or detonation of a nuclear weapon. The United States Department of Defence definition is: A device included in or attached to a nuclear weapon system to preclude arming and/or launching until the insertion… Read More

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What was the Vela Incident (1979)?

Introduction The Vela incident, also known as the South Atlantic Flash, was an unidentified double flash of light detected by an American Vela Hotel satellite on 22 September 1979 near the Prince Edward Islands in the Indian Ocean. The cause of the flash remains officially unknown, and some information about the event remains classified by… Read More

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What is Exercise Spade Fork?

Introduction Federal Emergency Plan D-Minus was a plan developed by the United States of America (US) in the 1950’s to guide the federal government in the immediate aftermath of a catastrophic nuclear attack. Plan D-Minus was part of the National Plan for Emergency Preparedness, which also included Mobilisation Plan C (providing direction for federal planning… Read More