The Vela Incident

The Vela Incident (sometimes known as the South Atlantic Flash) was the possible detection of a nuclear weapon test. This detection was made by a United States Vela satellite on September 22, 1979. Much of the information about the event is still classified. The Vela 6911 satellite apparently detected the characteristic double flash of an atmospheric nuclear explosion (first a very fast and very bright flash, and then a less bright and longer-lasting flash) of some two to three kilotons at 47°S 40°E / 47°S 40°E / -47; 40 near to the Prince Edward Islands, a South African dependency lying in the Indian Ocean. The technical evidence is however inconclusive. In a class of its own, the Vela series of highly sophisticated satellites were launched in pairs between 1963 and 1970 to detect nuclear detonations in the Earth’s atmosphere. Being part of an overall system consisting of Vela Uniform, to detect underground detonations, and Vela Sierra, to detect surface detonations (neither of which used satellite technology), the system is also known as Vela Hotel.

The satellites, which were built by TRW, were equipped with detectors to identify X-rays, gamma rays, and neutron emissions which were not only used to detect nuclear detonations, but were also effectively used to gather scientific data on solar flares and other solar radiation. There is much doubt as to whether the satellite's observations were accurate. The Vela Hotel 6911 satellite was one of a pair that had been launched on May 23, 1969, over ten years before the "double-flash" event, and this satellite was already more than two years beyond its so-called "design lifetime". This satellite was known to have a failed electromagnetic pulse (EMP) sensor, and it had developed a fault (in July 1972) in its recording memory, but that fault had cleared itself by March 1978.

On September 22, 1979, Vela 6911 detected two very distinct flashes in the vicinity of the Indian or South Atlantic oceans that supposedly could be only one thing: a nuclear detonation. The Carter administration held an emergency meeting, other satellites were enlisted to see if they saw the detonation, which they did not, and utter pandemonium ensued for a short time as the US government scrambled to see who or what had set off a nuclear weapon that day.

It was a small explosion, estimated at only three kilotons, and the Soviets, Chinese, French and British are unlikely as the originators. If the detection was a nuclear explosion, and not a natural phenomenon or malfunction, the two primary suspects for the sources of an unexplained nuclear blast were Israel and South Africa, both of which had covert nuclear weapons programs at the time. A test by either Israel or South Africa would have been very awkward for the Carter administration.

Israel was a close American ally, while the South African relationship was close but unpopular due to apartheid. Carter had worked hard on nonproliferation issues, and a vigorous response would have been required if it had been proven that either nation had conducted the test. This would have disrupted the negotiations underway over the Camp David Accords.

Technical information and analyses suggest that :
  • An explosion was produced by a nuclear device detonated in the atmosphere near the earth’s surface.
  • It had yield equivalent to less than 3 kilotons.
  • It took place within a broad area, primarily oceans, that was generally cloudy.
If a nuclear explosion did occur, it is uncertain who triggered it. There are difficulties with both the South African and Israeli hypotheses. South Africa did have a nuclear weapons program at the time, and the geographic location of the tests points to their involvement. Since the fall of apartheid, South Africa has disclosed most of the information on its nuclear weapons program, and according to the subsequent International Atomic Energy Agency (IAEA) report, South Africa did not have the capability to construct such a device until November 1979, two months after the incident.

However in September 1979 American signals intelligence detected unusual security measures at South Africa's Walvis Bay facility the week before the event, which led to suspicions that the putative test was staged from there. At that time some special security measures put into effect which indicate that certain elements of the South African Navy were exercising or on alert on 22 September. The harbor and naval base at Simonstown were declared, in a public announcement on 23 August, to be off limits for the period 17-23 September.

The US defense attache gathered from several reliable resources that harbor defense exercises took place there during this period. Although such a closure might not be required for a nuclear test at sea, it could have screened sensitive loading or unloading operations as well as ship movements.

Also, at Saldanha naval facility, which includes a naval search-and-rescue unit, was suddenly placed on alert for the period 21-23 September. The alert was not publicly announced, no explanation for it was given to naval personnel, and no activity was observed in on around the port. Furthermore, at the same time, General Malan, Chief of South Africa’s Defense Force, was reported to be touring South America, when he might have been expected to be in South Africa or at the test observation point during such an important event. Prime Minister Botha has avoided public comment on the issue since the US disclosure of the Vela indications.

Israel did have nuclear weapons in 1979, but it is questioned whether they had the capability to mount a covert test thousands of kilometers away. If it had been an Israeli test, it would almost certainly have been conducted with South African assistance and cooperation.

Problem is, the whole thing made no sense. The first problem was that no other satellites had detected the detonation, even though at least three were capable of it, if not more. It might have ended there, a very scary and potentially dangerous malfunction caused a false alarm. But it didn’t.

Astronomers working at the Arecibo radio telescope in Puerto Rico detected an atmospheric shockwave that could have been linked to a nuclear explosion. The US government’s hydrophone network detected a very clear echo of a large explosion. But the one piece of foolproof evidence was never found: radiation. Dozens of flights were conducted to try to detect fallout, and none was ever found, though extremely low levels of a certain radioactive element might have been detected in Australia, some time later.

Some specialists who examined the data speculated that the double flash, characteristic of a nuclear explosion, may have been the result of a nuclear weapons test: "The conclusions of the Presidential panel (the Ad Hoc Panel) were reassuring, as they suggested that the most likely explanation of the Vela detection was a meteoroid hitting the satellite — in part because of the discrepancy in bhangmeter readings. Others who examined the data, including Defense Intelligence Agency (DIA), the national laboratories, and defense contractors reached a very different conclusion — that the data supported the conclusion that on 22 September 1979, Vela 6911 had detected a nuclear detonation." However, it has never been ruled out that the "double flash" signal might have been a spurious electronic signal that was generated by an aging detector in an old satellite.

No corroboration of an explosion, such as the presence of nuclear wastes in the air, was ever made, although there were numerous passes in the area by U.S. Air Force planes that were specifically designed to detect airborne radioactive dust. It was also noted that some meteoroids as they enter the atmosphere produce explosive bursts measured from several kilotons of TNT (the Eastern Mediterranean Event) to megatons of TNT (the Tunguska Event). However in such cases the physical manifestations are normally distinct from those that were observed, since single meteors do not produce the double flash characteristic of a nuclear detonation.

The blast remains a secret to this day, despite South Africa having given up all nuclear weaponry and testing decades ago. If they did it, they still aren’t saying, even though they have no motivation to keep quiet after all this time. Only if it involved Israel would it be worth keeping secret still. Most likely, Israel tested a nuclear weapon, but how it managed to not produce detected fallout is a mystery.

Sources :
Interagency Intelligence Memorandum : “The 22 September 1979 Event”. National Security Archive. December 1979;
MilsatMagazine January 2009;;;

Pics Sources :
MilsatMagazine January 2009 page 32
The Vela Incident The Vela Incident Reviewed by Tripzibit on 04:48 Rating: 5


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  4. Your writeup is fantastic. I covered this back in September, but you went into so much more detail!

    I have a suggestion for a mystery:

  5. (@Fish Hawk) Thank you very much

    (@Steve Bush) Well, actually i'm just an amateur blogger. Anyway,thanks for the compliment and big thanks to all my sources that provide more details.

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