Vela incident

The Vela incident was an atmospheric nuclear explosion that occurred on 22 September 1979, near the South African territory of Prince Edward Islands in the Indian Ocean, roughly midway between Africa and Antarctica. This explosion is widely believed to have been an undeclared test of an Israeli nuclear weapon on the ocean surface, carried out with assistance from South Africa. Initially detected as a double flash of light by an American Vela Hotel satellite, further meteorological satellite, hydroacoustic,

In 1980, US President Jimmy Carter wrote in his diary, "We have a growing belief among our scientists that the Israelis did indeed conduct a nuclear test explosion in the ocean near the southern end of Africa." If conducted by Israel, it was in contravention of Israel's 1964 ratification of the Partial Nuclear Test Ban Treaty.

The previous 41 double flashes detected by the Vela satellites were caused by atmospheric nuclear tests. Some traces of potential nuclear fallout were detected in Australia but not New Zealand. Some information about the event remains classified by the United States government.), which carried various sensors designed to detect nuclear explosions that contravened the Partial Nuclear Test Ban Treaty (assuming that it was done by a signatory).

As well as 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.

The satellite reported a double flash potentially characteristic of an atmospheric nuclear explosion of two to three kilotons, in the Indian Ocean between the Crozet Islands (a sparsely inhabited French possession) and the Prince Edward Islands (which belong to South Africa) at .

Acoustic data of the Sound Surveillance System (SOSUS), established by the United States to detect Soviet submarines, and the Missile Impact Locating System (MILS), designed to detect missile nose cone impact locations of test missiles in the Atlantic and Pacific test ranges, were searched for evidence of a nuclear detonation in the region. These data were found not to have enough substantial evidence of a detonation of a nuclear weapon but a detailed, affirming study regarding MILS data correlating with time and location of the Vela flash was not considered in that finding. United States Air Force (USAF) surveillance aircraft flew 25 sorties over that area of the Indian Ocean from 22 September to 29 October 1979 to carry out atmospheric sampling. Studies of wind patterns confirmed that fallout from an explosion in the southern Indian Ocean could have been carried from there to southwestern Australia. It was reported that low levels of iodine-131 (a short-half-life product of nuclear fission) were detected in sheep in the southeastern Australian states of Victoria and Tasmania soon after the event. Sheep in New Zealand showed no such trace. The Arecibo Observatory, in Puerto Rico, detected an anomalous ionospheric wave during the morning of 22 September 1979, which moved from the southeast to the northwest, an event that had not been observed previously.

thumb|left|upright|[[Bhangmeter light patterns detected by a pair of sensors on Vela satellite 6911 on 22 September 1979]]

After the event was made public, the United States Department of Defense (DOD) clarified that it was either a bomb blast or a combination of natural phenomena, such as lightning, a meteor, or a glint from the sun. The initial assessment by the United States National Security Council (NSC), with technical support from the Naval Research Laboratory, in October 1979 was that the American intelligence community had "high confidence" that the event was a low-yield nuclear explosion, although no radioactive debris had been detected and there were "no corroborating seismic or hydro-acoustic data". A later NSC report revised this position to "inconclusive" about whether a nuclear test had occurred.

Office of Science and Technology evaluation

The Carter administration asked the Office of Science and Technology Policy (OSTP) to convene a panel of instrumentation experts to re-examine the Vela Hotel 6911 data, and to attempt to find whether the optical flash detected came from a nuclear test. The outcome was politically important to Carter, as his presidency and 1980 re-election campaign prominently featured the themes of nuclear nonproliferation and disarmament. The SALT II treaty had been signed three months earlier, and was pending ratification by the United States Senate, and Israel and Egypt had signed the Camp David Accords six months earlier.

In the 2008 book The Nuclear Express: A Political History of the Bomb and its Proliferation, Thomas C. Reed and Danny B. Stillman stated their opinion that the "double flash" was the result of a joint South African–Israeli nuclear bomb test. David Albright stated in his article about the "double flash" event in the Bulletin of the Atomic Scientists that "If the 1979 flash was caused by a test, most experts agree it was probably an Israeli test".

In 2010, it was revealed that, on 27 February 1980, President Jimmy Carter wrote in his diary, "We have a growing belief among our scientists that the Israelis did indeed conduct a nuclear test explosion in the ocean near the southern end of Africa."

Leonard Weiss, of the Center for International Security and Cooperation at Stanford University, writes: "The weight of the evidence that the Vela event was an Israeli nuclear test assisted by South Africa appears overwhelming."

According to Israeli nuclear program defector Mordechai Vanunu, Israel only gained a production-scale highly enriched uranium plant and possible boosted fission or thermonuclear capability after 1980, implying that the weapon was an unboosted implosion device using plutonium from the Dimona reactor.

Reed has written that he believes the Vela incident was an Israeli neutron bomb test. The test would have gone undetected as the Israelis specifically chose a window of opportunity when, according to the published data, no active Vela satellites were observing the area. Although the decade-old Vela satellite that detected the blast was officially listed as "retired" by the US government, it was still able to receive data. Additionally, the Israelis chose to set off the test during a typhoon. By 1984, according to Vanunu, Israel was mass-producing neutron bombs.

South Africa

The Republic of South Africa also had a clandestine nuclear weapons program at the time, and is located in the region of the incident. Later, concurrent with the end of apartheid, South Africa disclosed most but not all of the information on its nuclear weapons programme. Later inspections by the International Atomic Energy Agency (IAEA) in 1993 concluded that South Africa could not have constructed a nuclear bomb until November 1979, two months after the "double flash" incident, as South Africa did not have enough highly enriched uranium in their possession at the time of the incident. Furthermore, the IAEA reported that all possible South African nuclear bombs had been accounted for.

France

Since the "double flash", if one existed, could have occurred not very far to the west of the French-owned Kerguelen Islands, it was a possibility that France was testing a small neutron bomb or other small tactical nuclear bomb.

Subsequent developments

thumb|upright|right|1981 Los Alamos report as cited

Since 1980, some small amounts of new information have emerged but most questions remain unanswered. A Los Alamos Scientific Laboratory report from 1981 notes:

In October 1984, a National Intelligence Estimate on the South African nuclear program noted: A shorter form of this wording was used in a subsequent National Intelligence Council memorandum of September 1985.

In February 1994, Commodore Dieter Gerhardt, a convicted Soviet spy and the commander of South Africa's Simon's Town naval base at the time, talked about the incident upon his release from prison. He said:

Gerhardt further stated that no South African naval vessels had been involved, and that he had no first-hand knowledge of a nuclear test. In 1993, then President F. W. de Klerk admitted that South Africa had indeed possessed six assembled nuclear weapons, with a seventh in production, but that they had been dismantled (before the first all-race elections of April 1994). There was no mention specifically of the Vela incident or of Israeli cooperation in South Africa's nuclear program. On 20 April 1997, the Israeli daily newspaper Haaretz quoted the South African deputy foreign minister, Aziz Pahad, as supposedly confirming that the "double flash" from over the Indian Ocean was indeed from a South African nuclear test. Haaretz also cited past reports that Israel had purchased 550 tons of uranium from South Africa for its own nuclear plant in Dimona. In exchange, Israel allegedly supplied South Africa with nuclear weapons design information and nuclear materials to increase the power of nuclear warheads. Pahad's statement was confirmed by the United States embassy in Pretoria, South Africa, but Pahad's press secretary stated that Pahad had said only that "there was a strong rumour that a test had taken place, and that it should be investigated". In other words, he was merely repeating rumours that had been circulating for years. David Albright, commenting on the stir created by this press report, stated:

In October 1999, a white paper that was published by the United States Senate Republican Policy Committee in opposition to the Comprehensive Test Ban Treaty stated:

In 2003, Stansfield Turner, the Director of Central Intelligence (DCI) during the Carter administration, stated that the Vela detection was of a "man-made phenomenon". In his 2006 book On the Brink, the retired CIA clandestine service officer Tyler Drumheller wrote of his 1983–1988 tour-of-duty in South Africa:

In 2010, Jimmy Carter published his White House Diary. In the entry for 22 September 1979, he wrote "There was indication of a nuclear explosion in the region of South Africa—either South Africa, Israel using a ship at sea, or nothing." For 27 February 1980, he wrote "We have a growing belief among our scientists that the Israelis did indeed conduct a nuclear test explosion in the ocean near the southern end of Africa." In 2018, a new study made the case for the double flash being a nuclear test. A 2022 study examining readings from the NASA satellite Nimbus-7 taken 16 minutes and 44 seconds after the explosion found evidence of a trace left by the blast's shockwave in the ozone layer.

In popular culture

The West Wing episode "The Warfare of Genghis Khan" includes an element based on the Vela incident.
The Vela incident plays into the plot of Jonas Jonasson's novel The Girl Who Saved the King of Sweden.

References

Notes

Footnotes

Citations

Released by FOIA request, Frank Ruina, chair, 23 May 1980.

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