Written by Alan Bellows
On 22 September 1979, sometime around 3:00am local time, a US Atomic Energy Detection System satellite recorded a pattern of intense flashes in a remote portion of the Indian Ocean. Moments later an unusual, fast-moving ionospheric disturbance was detected by the Arecibo Observatory in Puerto Rico, and at about the same time a distant, muffled thud was overheard by the US Navy’s undersea Sound Surveillance System (SOSUS). Evidently something violent and explosive had transpired in the ocean off the southern tip of Africa.
Examination of the data gathered by satellite Vela 6911 strongly suggested that the cause of these disturbances was a nuclear device. The pattern of flashes exactly matched that of prior nuclear detections, and no other phenomenon was known to produce the same millisecond-scale signature. Unfortunately, US intelligence agencies were uncertain who was responsible for the detonation, and the US government was conspicuously reluctant to acknowledge it at all.
The United States established the Vela satellite network in the 1960s for the specific purpose of monitoring compliance with the 1963 Partial Test Ban Treaty. Though each satellite’s intended lifespan was only eighteen months, the units continued to detect detonations for years thereafter. Prior to the mysterious event of September 1979, the orbital surveillance system had successfully recorded forty-one atomic detonations, twelve of which were spotted by satellite Vela 6911.
Though the Vela satellites were bristling with atom-bomb sensing equipment, their most effective apparatus was each unit’s pair of aptly-named bhangmeters. These photodiode arrays were tuned to detect the one-millisecond burst of intense light created by a nuclear fireball, and the subsequent secondary light caused by the hydrodynamic shockwave of ionized air. The sensor’s engineers had been skeptical of its potential— hence their decision to name it after the Indian variation of cannabis called “bhang”— but the predictable pattern of bright flashes proved to be an extremely effective method for detecting atomic explosions from orbit. In over a decade of operation, the network of unblinking electronic eyes had yet to record a single false positive with the atomic-bomb signature.
Due to the satellites’ design and their distant orbit of 70,000 miles, technicians were not furnished with the exact location of nuclear events; the sensors could only narrow the area down to a 3,000 mile radius. Available data suggested that the 1979 Vela incident occurred near Bouvet Island, a frozen scrap of earth famous as the most isolated isle in the world. The tiny island was home to a Norwegian automated weather station, and in 1964 an abandoned lifeboat of unknown origin was found there, filled with supplies. But presumably the island was completely uninhabited at the time of the energetic event, meteorological automatons and enigmatic castaways notwithstanding.
https://www.damninteresting.com/the-vela-incident/
