Vela Incident:

The Vela Incident (sometimes referred to as the South Atlantic Flash) was an as-yet unidentified double flash of light detected by a United States Vela satellite on September 22, 1979. It has been speculated that the double flash, characteristic of a nuclear explosion, was the result of a nuclear weapons test; however, recently declassified information about the event concludes that it "was probably not from a nuclear explosion, although [it cannot be ruled] out that this signal was of nuclear origin."^[1]

Detection

The flash was detected on 22 September 1979, at 00:53 GMT, by US Vela satellite 6911, which carried various sensors designed specifically to detect nuclear explosions. In addition to being able to detect gamma rays, x-rays and neutrons, the satellite also contained two bhangmeter sensors which were able to detect the dual light flashes associated with a nuclear explosion, specifically the initial brief, intense flash as well as the second longer flash that followed.^[2]

There is much doubt^[4] as to whether the satellite's observations were accurate. Vela 6911 was one of a pair launched on 23 May 1969, more than ten years prior to the event, and the satellite was already two years past its design lifespan. It was known to have a failed electromagnetic pulse (EMP) sensor and had developed a fault (in July 1972) in its recording memory, but the fault had cleared itself by March 1978.

Initial assessment by the U.S. National Security Council in October 1979^[5] was that the intelligence community had "high confidence" that the event was a low-yield nuclear explosion, although no radioactive debris was detected, and there was "no corroborating seismic or hydro-acoustic data."^[5] A later NSC report revised this to "a position of agnosticism" about whether a test had occurred.^[6] They concluded that responsibility should be ascribed to South Africa.^[5]^[6]. Later, the Carter administration asked the Office of Science and Technology Policy (OSTP) to convene a panel of instrumentation experts to examine the Vela 6911 data and determine whether the optical flash detected was from a nuclear test.

Office of Science and Technology Evaluation

An independent panel of experts was commissioned by Frank Press, who was the Science Advisor to the President and chair of the OSTP, to evaluate the evidence and determine the likelihood that the event was a nuclear detonation. This panel was chaired by Professor Jack Ruina of MIT, the former director of the Department of Defense Advanced Research Projects Agency. Reporting in the summer of 1980, the panel noted that there were some key differences in the detected optical signature from an actual nuclear explosion, particularly in the ratio of intensities measured by the two detectors on the satellite and that, although the brightness of the flash was explainable only if the flash had occurred in a cloud-free region, the lack of any nuclear debris found by 25 aircraft overflights could be explained only by a detonation in a heavily overcast site. "Based on our experience in related scientific assessments," it was their collective judgement that the signal was spurious. The panel's conclusion was that the signal "was probably not from a nuclear explosion, although we cannot rule out that this signal was of nuclear origin." The now-declassified report^[1] contains details of the measurements made by the Vela satellite. The panel was not able to conclude definitively what the event actually was. The best analysis that they could do of the data suggested that, if the sensors were properly calibrated, the event was about 30 meters away from the satellite (and hence was a small event close up, not a big event far away). This was consistent with the hypothesis that a micrometeoroid had impacted the satellite, ejecting a small cloud of debris into space, which reflected sunlight into the sensors.

The fact that the explosion was picked up by only one of the two Vela satellites seems to support the panel's assertion. The Vela satellites had previously detected 41 atmospheric tests, each of which was subsequently confirmed by other means. The absence of corroboration of a nuclear origin for the Vela Incident also suggests that the signal was spurious.

Some, however, cast doubt on the panel's findings, arguing that they were politically motivated.^[7] Evidence to corroborate the nuclear hypothesis has been gathered. There was some data that seemed to confirm that a nuclear explosion was the source for the signal. The radio telescope at Arecibo, Puerto Rico, also detected an anomalous traveling ionospheric disturbance at the same time.^[7] A test in Western Australia conducted a few months later found increased radiation levels.^[8] However a detailed study done by the New Zealand National Radiation Laboratory found no such evidence as did a U.S. government laboratory.^[9] The Los Alamos scientists who worked on the Vela program remain convinced that their satellite worked properly.^[7]

Likely responsibility

If a nuclear explosion did occur, it occurred within the 3,000 miles (4,800 km) wide circle covering the Indian Ocean, South Atlantic, southern tip of Africa, and a small part of Antarctica.^[10]

South Africa

South Africa did have a nuclear weapons program at the time, and it falls within that geographic location. Nevertheless, 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 report, South Africa could not have constructed such a device until November 1979, two months after the incident. Furthermore the IAEA reported that all South African nuclear devices had been accounted for. A report dated 21 January 1980 prepared by the Central Intelligence Agency for the U.S. Arms Control and Disarmament Agency concluded in paragraph 41 that:^[11]

Israel

Israel had nuclear weapons in 1979, but it is questioned^{[by whom?]} whether they had the capability to mount a covert test thousands of kilometres away. If it had been an Israeli test, it was almost certainly done with South African cooperation.^{[citation needed]}

India

India had carried out a nuclear test in 1974 (see Smiling Buddha). The possibility that India would test a weapon was considered, since it would be normal for the Indian Navy to operate in those waters, but dismissed as impracticable and unnecessary.^[12] India was not considered as a potential partner of South Africa's nuclear program as it was one of the most vocal critics of the racist apartheid regime in Pretoria and maintained diplomatic and military sanctions on South Africa.

Other

U.S. analysts also considered the possibility that it could have been a covert test by a known nuclear state. They concluded that there would be little motivation for the USSR or China in particular to test a nuclear weapon in such a way, unless they were attempting to make it look like South Africa or Israel were covertly testing weapons. As the flash could have occurred in the vicinity of the Kerguelen Islands, it is possible that France was testing a neutron bomb.^[10]

It is unlikely any other declared nuclear powers would have conducted such a test. They had little reason to conduct an atmospheric test, and the small size of the blast might reflect a less advanced weapon – though there are many "advanced" reasons for small tests as well, including tactical nuclear weapons (such as neutron bombs) and testing the primary devices for thermonuclear weapons.^{[citation needed]}

Sometimes also mentioned as another potential partner for South Africa in such a test is Taiwan.^{[citation needed]}

United Nations Security Council Resolution 418 of November 4, 1977 introduced a mandatory arms embargo against South Africa, also requiring all States to refrain from "any co-operation with South Africa in the manufacture and development of nuclear weapons".^[13] This prohibition could explain why other countries are so reluctant to admit involvement with South Africa's nuclear weapons program.^{[original research?]}

Subsequent developments

Since 1980 some new information has emerged. However, most questions remain unanswered:

Some related U.S. information has recently been declassified in the form of heavily redacted reports and memoranda following applications made under Freedom of Information Act. On May 5, 2006, many of these declassified documents were made available through the National Security Archive.

Vela Incident

Contents

Detection

Office of Science and Technology Evaluation

Likely responsibility

South Africa

Israel

India

Other

Subsequent developments

See also

Fiction

References

External links