The Vela Incident refers to an event that occurred in late September 1979. The United States, as one of the world's premier nuclear powers, had invested a great deal of effort and resources into obtaining and maintaining the ability to detect nuclear detonations around the world. The satellites of the Defense Support Program, the Defense Meteorological Support Program and the Satellite Data System (all primarily intended for other missions) all carried sensitive instruments which were designed to detect these detonations from space. In addition to these, however, there were dedicated platforms. In 1963, the U.S. had begun a project named Vela in order to monitor the Soviet Union's compliance with the just-signed Partial Test Ban Treaty. Project Vela involved the construction, launch and operation of a number of satellites intended to monitor both local space and the Earth's surface for any sign of nuclear detonations.
Vela 6911 was an Advanced Vela type satellite launched (it is believed) on May 23rd, 1969. It carried X-Ray, EMP and neutron detectors as well as bhangmeters. Although it had an original design lifespan of 18 months, it was still in operation in 1979 - whether as an officially operating satellite or not is unclear - as the Advanced Vela satellites had their expected lifespan ratings increased dramatically after several months of operation and testing. Vela 6911 was operating in a orbit with a perigee of 77,081 km and an apogee of 145,637 km, with an orbital inclination of 61.6 degrees.
On September 22, 1979 technicians at the Air Force Technical Applications Center in Florida downloaded the most recent stored observational data from Vela 6911. Among the data were recordings which showed that at around 0053 GMT on that day, Vela 6911's bhangmeters had recorded the characteristic 'double flash' of what appeared to be a nuclear detonation. The event had occurred approximately 1000-2000 miles southeast of South Africa, in the Indian Ocean. This caused an immediate flurry of activity. Then-President Jimmy Carter had made non-proliferation a cornerstone of his foreign policy, which meant that if this event had been a nuclear detonation, a foreign policy failure had just occurred. A panel of scientists was convened to determine whether this event was, in fact, a nuclear detonation - and, some claim, to offer the Carter administration some cover if doubt could be cast on the detection's accuracy. It was known as the Ruina Panel, after its head, Dr. Jack Ruina. Dr. Ruina had been head of DARPA in the early 1960s during the initial creation of the Vela project, although he arrived after it was underway. He had served as a consultant, after his departure, to the Vela project on seismic affairs.
As the panel worked, data was flowing in from various efforts. The U.S. Air Force dispatched atmospheric sampling aircraft to attempt to find radioactive traces of a detonation. The Central Intelligence Agency apparently sent agents to islands in the predicted wind patterns downwind of the event location to retrieve samples of leaves to see if any residue could be detected. Data from the other NUDETS systems aboard the Defense Support Program satellites was examined, and it was found that those sensors had not recorded anything that looked like nuclear detonation. However, observations taken at the Arecibo Ionospheric Observatory showed a pressure wave traveling in the ionosphere which was not explainable by current weather and solar conditions, and which could have been caused by a blast at the observed location. There were reports of iodine-131 (a short-lived fallout contaminant) being found in the thyroid glands of sheep slaughtered in Australia in November that year. And so on.
Of the 41 times prior to this event where a Vela satellite had recorded a bhangmeter flash, all 41 had subsequently been confirmed by other means - so, as the Cold War catchphrase goes, 'confidence was high.' However, there were discrepancies even in the data from the satellite - discrepancies, or anomalies. The interval between the flashes and the second flash apparently looked different from previously recorded Vela detections. Two of the bhangmeters aboard Vela 6911, expected to show similar ratios of time involving the flash durations and separations, showed different ratios - possibly because they had degraded differently with age. The electromagnetic pulse detectors aboard Vela 6911, usually used to confirm a detonation, were no longer in service as the satellite was a decade old, and by this time three years past even its extended life expectancy.
On October 25, 1979 the issue became more urgent from an American domestic policy standpoint, as an ABC TV reporter (John Scali) broke the story of the possible detonation after receiving briefings on it from contacts he had within the Department of Defense. The Ruina Panel released a report of its findings in July 1980, although it was classified. The report detailed all the various reasons to doubt the contact - but also totted up some impressive corroborating evidence. Once of the most dramatic, which was made public, was the fact that the U.S. Naval Research Laboratory confirmed that there was hydrophone acoustic data showing signals both directly detected from the event area as well as reflected from the Antarctic Ice Shelf whose timing and nature, the NRL stated, was consistent with a small (~3 kiloton TNT equivalent) blast either directly above or just under the surface of the ocean. It should be pointed out that much of the various evidence gathered from various organizations was not innovative - these organizations had been involved in monitoring U.S., allied and opponent nuclear tests since the Trinity test which started the Atomic Age.
However, those on the panel were not convinced. The failure to detect fallout via atmospheric sampling weighed heavily, as did an examination of the total sensor logs of the Vela 6911 satellite. Those sensors which failed to detect the event, claimed Luis Alvarez (a Nobel prize-winning physicist on the panel) nevertheless did not show evidence of inaccuracy either before or after the event. As a result, the panel seems to have decided that the event could not be determined to be a nuclear detonation (Los Alamos National Laboratory, it should be noted, did not concur that the other sensors failed to show the blast). Alternative explanations were offered - that the satellite itself had suffered an event, namely a micrometeoroid impact, which caused some of the sensors to record readings that appeared to be a detonation on the surface, while those sensors not directly affected showed nothing. Or perhaps the detonation had been that of a meteoroid striking the atmosphere and exploding. Or even that the flashes had been super-powerful lighting bolts.
It's difficult to say, more than thirty years later, what happened. Some scientists and nuclear historians are convinced that there was, in fact, a detonation detected by Vela 6911. Some point to the report and say that the minimum acceptable level of proof was not reached.
The real question, of course, was simple: if this had been a nuclear detonation, who did it? The primary suspect was in fact an ally of the United States - Israel was widely known to have been pursuing an atomic weapons capability, and in addition had been known to have close arms industry ties with South Africa, very near to where the event was recorded. Among those who believed that the event was, in fact, a real detonation, there was very little doubt that it was an Israeli test - possibly with South African assistance - which had produced the blast. This point of view received support over a decade later, when in 1993 President de Klerk revealed in a speech that South Africa had in fact constructed seven atomic weapons as a deterrent, with the first being completed in the early 1980s - but had decided unilaterally (and secretly) to dismantle them and give up the capability in 1990. In addition, it came out, the Soviet Union had detected South Africa preparing for underground atomic tests on land in 1977 via satellite observations, and reported this fact to the United States, resulting in the US, USSR and France all pressuring South Africa into canceling those tests. Given that, an offshore, more-deniable test (which might have served both South Africa and their putative ally Israel) a mere two years later looks very plausible.
As time has passed, the evidence seems to have accrued that shows there was, in fact, a nuclear detonation off South Africa in 1979. The Vela program's prior perfect record of detection, coupled with the increase in available information about the nuclear ambitions of regional powers, all (in the writer's opinion) point to this being an actual test, detected by systems designed to do just that. The confusion and dispute over the detection are, in fact, easily explained both by the age of the satellite and hence the less-than-ideal record, as well as by the political climate of the time - specifically that a close ally of the United States might have been involved during a period when the U.S. was officially pursuing a non-proliferation foreign policy.
(IN 5 25/30)
- The Nuclear Weapon Archive - The Vela Incident
- Los Alamos Bulletin: Blast from the Past - scientists receive vindication
- Hersh, Seymour. "The Samson Option: Israel's Nuclear Arsenal and American Foreign Policy." New York: Random House, 1991
- George Washington University National Security Briefing Book - The Vela Incident: Nuclear Test or Meteoroid?
- Nonproliferation Policy and Education Center: Israel’s 1979 Nuclear Test and the U.S. Government’s Attempt to Cover It Up
- Pabian, Frank. "Reviwing the Evidence on South Africa and the Bomb," in The Bulletin of the Atomic Scientists, April 1988 (pp. 47-88)
- Central Intelligence Agency 'interagency memorandum' titled 'The 22 September 1979 Event', prepared for the U.S. Arms Control and Disarmament agency (Classified SECRET, declassified in June 2004) - CIA MORI Document ID 1108245
- Babbage, Maria. "Why South Africa Gave Up the Bomb and the Implications for Nuclear Nonproliferation Policy," in The Journal of Public and International Affairs, Vol. 15. Princeton NJ: Princeton University Press, 2004.
- Federation of American Scientists guide entry on South African nuclear weapons program.
- Notes from interview with Dr. J.P. Ruina for the American Institute of Physics Oral History archive - Kai-Henrik Barth, interview taken at MIT in 1998.
- Personal conversations with Jack Ruina (the author studied at MIT where Dr. Ruina was a Professor Emeritus in his department)