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.

Detection

The flash was detected by one of the Vela satellites developed to detect nuclear explosions. On 22 September 1979 at 00:53 GMT, 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 near to the Prince Edward Islands, a South African dependency lying in the Indian Ocean.

Vela 6911 was one of the pair launched on 23 May 1969, over ten years before the possible explosion. It was operating two years past its designed lifespan and its electromagnetic pulse (EMP) sensor had failed. It had also developed a fault in July 1972 where around half a second of its recording memory had failed. This had cleared itself in March 1978.

It is still uncertain whether the satellite's observations were accurate. Following the incident, the Carter administration summoned a panel of experts headed by Jack Ruina to consider the reliability of the Vela 6911 data. Reporting in the summer of 1980, the panel concluded that the signal "was probably not from a nuclear explosion. Although we cannot rule out that this signal was of nuclear origin". The panel proposed that the satellite was in error and had perhaps been hit by a small meteorite. The fact that the explosion was only picked up by one of the satellites seems to support the panel's assertion. United States Air Force flights in the area soon after also failed to detect any sign of radiation.

Many doubt the panel's findings, arguing they were politically motivated. A considerable amount of evidence corroborating the nuclear hypothesis has been gathered. The Vela satellites previously detected 41 atmospheric tests, each of which had been subsequently confirmed through other means. There was some other data that seemed to confirm the explosion. Hydrophones operated by the US Navy detected a signal which was consistent with a small nuclear explosion on or slightly under the surface of the water near Prince Edward Islands. The radio telescope at Arecibo, Puerto Rico, also detected an anomalous traveling ionospheric disturbance at the same time. A test in Western Australia conducted a few months later found increased radiation levels.Frank Barnaby. 1989. The Invisible Bomb, I.B. Tauris & Co. Ltd., ISBN 1-85043-078-0 The Los Alamos scientists who worked on the Vela program remain convinced that their satellite worked properly.

It has also been proposed that there was an explosion, but one caused by a comet or other natural cause.

Responsibility

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.

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. However, since the fall of apartheid, South Africa has disclosed most of the information on its nuclear weapons program, and according to the subsequent IAEA report, South Africa did not have the capability to construct such a device until November 1979, two months after the incident.

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

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. The possibility that India would test a weapon was considered, since it would be normal for Indian ships to be in those waters, but dismissed as both impracticable and probably not within their limited nuclear capabilities.See Jeffrey Richelson, Spying on the Bomb: American Nuclear Intelligence from Nazi Germany to Iran and North Korea (New York: W. W. Norton, 2006), chapter seven, "The Double Flash".

It is unlikely any of the then 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 so-called neutron bombs) and testing the primary devices for thermonuclear weapons.

Sometimes also mentioned as another potential partner for South Africa in such a test is Taiwan.

Subsequent developments

Since 1980 some new evidence has emerged; however, most questions remain unanswered.

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

"Although I was not directly involved in planning or carrying out the operation, I learned unofficially that the flash was produced by an Israeli-South African test code-named Operation Phenix. The explosion was clean and was not supposed to be detected. But they were not as smart as they thought, and the weather changed – so the Americans were able to pick it up."David Albright. 1994. South Africa and the Affordable Bomb

On 20 April 1997, the Israeli daily newspaper Ha'aretz, quoted South African Deputy Foreign Minister Aziz Pahad as confirming that the flash over the Indian Ocean was indeed from a South African nuclear test. Soon afterwards Pahad reported that he had been misquoted and that he was merely repeating the rumors that had been circulating for years.

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-released legislation, but nothing that provides conclusive proof over the incident one way or the other. On May 5, 2006 these documents were made available through the National Security Archive.

References

1979 | Nuclear tests | Israeli nuclear development | Nuclear weapons programs | Modern weapons of South Africa

Vela-Zwischenfall

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Detection

Responsibility

Subsequent developments

References