Vela Incident

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 off Antarctica, which many believe was of nuclear origin. The most widespread theory among those who believe the flash was of nuclear origin is that it resulted from a joint South African-Israeli nuclear test. The topic has been highly disputed. In 2016 researchers from George Washington University's National Security Archive noted that the debate over the South Atlantic flash has shifted over the last few years to the side of a man-made weapon test.

While a "double flash" signal is characteristic of a nuclear weapons test in the atmosphere, the signal could also have been a spurious electronic signal generated by an ageing detector in an old satellite, or a meteoroid hitting the Vela satellite. No corroboration of an explosion, such as the presence of nuclear byproducts in the air, was ever publicly acknowledged, even though there were numerous passes in the area by Boeing WC-135s, planes designed by the U.S. Air Force to detect airborne radioactive dust. Other examiners of the data, including the Defense Intelligence Agency (DIA), the U.S. Naval Research Laboratory (NRL), and defense contractors, have come to the conclusion that the flash was not a result of a nuclear detonation. Portions of the information about the event remain classified.

The "double flash" was detected on 22 September 1979, at 00:53 GMT, by the American Vela satellite 6911, which carried various sensors designed specifically to detect nuclear explosions that contravened the Partial Nuclear Test Ban Treaty. In addition to being able to detect gamma rays, X-rays, and neutrons, the satellite also contained two silicon solid-state bhangmeter sensors that could detect the dual light flashes associated with an atmospheric nuclear explosion: the initial brief, intense flash, followed by a second, longer flash.

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