Significant events in 1979: the Shah left Iran, the Three Mile Islandreactor suffered a partial core meltdown, and a clandestine nuclear testoff the tip of South Africa was detected by an aging satellite, Vela 6911.This is an article excerpted from the LASL Daily Newsbulletin of Friday, July 11, 1997.
To the Daily News Bulletin at Los Alamos
Friday, July 11, 1997
Blast from the past: Lab scientists receive vindication
Significant events in 1979: the Shah left Iran, the Three Mile Islandreactor suffered a partial core meltdown, and a clandestine nuclear testoff the tip of South Africa was detected by an aging satellite, Vela 6911.
Two of those world events made headlines, one remained both a partialmystery and an ongoing controversy until this year.
In an April 20 article that appeared in the Israeli Ha'aretz Daily Newspaper,South African Deputy Foreign Minister Aziz Pahad confirmed for the firsttime that a flare over the Indian Ocean detected by an American satellitein September 1979 was from a nuclear test. This statement was confirmedby the American Embassy in Pretoria, South Africa, as an accurate accountof what Pahad officially acknowledged. The article said that Israel helpedSouth Africa develop its bomb designs in return for 550 tons of raw uraniumand other assistance.
Eighteen years have passed since the flash was picked up by the Velasatellite. With Pahad's revelation, Laboratory scientists say, this controversycan at last reach closure. Original analyses conducted by Lab scientistsand others in the U.S. intelligence community said the flash could onlybe from a nuclear test. Now, their studies have been vindicated.
In 1979, the same analyses had been vigorously challenged by the Carteradministration. The challenge was driven by a general mistrust in agingsatellites and an unwillingness to accept the efficacy of other evidence.Instead, the Carter administration assembled a panel of scientists fromacademia to review the data. After their review, the panel concluded that,lacking independent collaborative data to support a nuclear origin of thesignals, the original interpretation of the satellite data could not bejustified.
The panel said the flash could have been caused by a combination of naturalevents, specifically a micrometeorite impact on the detector sunshade, followedby small particles ejected as a result of the impact. But Los Alamos scientistswere not dissuaded.
"The whole federal laboratory community came to the conclusion thatthe data indicated a bomb," said Dave Simons of Nonproliferation andArms Control Research and Development (NIS-RD). "But in the administration'sview, because the evidence was weak, they took exception to the informationand our analysis."
"It was unsettling because we were quite thoroughly convinced ofour interpretation," Simons said.
The Vela satellites were deployed in support of the Limited Test BanTreaty of 1963 and carried sensors designed at the Lab and Sandia NationalLaboratories to detect nuclear explosions in the atmosphere and in space.The satellites were launched in pairs beginning in 1963. The last and sixthpair was launched in 1970. Each satellite carried two optical sensors, calledbhangmeters, to view Earth and detect atmospheric nuclear explosions associatedwith unique, telltale signatures of brief, intense light pulses. The satellitesalso carried an electromagnetic pulse sensor.
One of the problems with the Vela's optical data was that one sensordetected more light than did another, more sensitive one. The discrepancysuggested to the White House-assembled panel that the bhangmeters saw anevent close at hand, perhaps sunlight glinting off a bit of meteor debristhat had bounced against the satellite. The panel maintained their conclusionseven though similar discrepancies had been observed in Vela signals fromprevious confirmed atmospheric nuclear tests.
In addition to the very bright optical signals, an atomic explosion alsounleashes a pulse of radiation at radio wave frequencies which can be detectedby EMP sensors. This electromagnetic pulse covers much of the radio wavespectrum.
Other radiation emitted by the blast includes gamma and beta rays andneutrons, which, in the case of a sea level or low-altitude explosion, areabsorbed by the atmosphere giving rise to electromagnetic radiation at frequenciesextending over the entire range from radio waves to the ultraviolet. Detectorson satellites are capable of sensing at least some of these instantaneoussignals, but if the radiation is missed in the first instant, then theyare gone forever, traveling away from Earth at the speed of light.
Although its optical sensors were still functioning, the Vela satellitethat detected the 1979 blast was operating beyond its seven-year life span.Because of the satellite's age, the EMP sensor was not operating.
After the detection of the September 1979 event, the United States governmentquickly launched a major effort to collect corroborating evidence that focusedon finding radioactive bomb fission products in the environment. But thesampling attempts never entered the low pressure air mass that had beenover the location of the time of the explosion. While low levels of iodine-131,a short-lived radioactive fission product, were detected in sheep thyroidsin western Australia, these results were also questioned.
In addition to detection satellites, the United States maintains a globalnetwork for detecting other atomic explosion phenomena, including soundwaves, seismic shock waves traveling through Earth, and hydroacoustic pulsestraversing Earth's oceans. Of these, the best data were from the hydroacousticsignals collected on devices called hydrophones. The hydrophone data indicatedsignals both from a direct path and from a reflection of the Antarctic'sScotia Ridge. Analyses of these signals conducted by the Naval ResearchLaboratory confirmed that they had been generated at a time and locationconsistent with the Vela 6911 detection and that their intensity was consistentwith a small nuclear explosion on, or slightly under, the ocean's surface.
More evidence came from a Lab researcher using a radio telescope foran unrelated project in Arecibo, Puerto Rico, detected a traveling ionosphericdisturbance - a ripple in Earth's upper atmosphere - moving south to northduring the early morning hours of Sept. 22, 1979, something researchershad never before witnessed.
But such evidence was discounted by the White House panel.
In 1979, the South African government adamantly denied the test. FormerForeign Minister Roelof Botha said he knew nothing of the blast and suggestedthe American government question the Chinese or Russians. But Botha stoppedshort of saying that South Africa had not detonated a bomb or that the countryhad no intention of acquiring nuclear weapons.
The flurry over the issue exemplified American nervousness in world affairs,Botha added.
However, Lab scientists remained convinced that the flash was a nucleardetonation and invested substantial effort in analyzing the signal. Subsequently,Lab researchers published an unclassified paper describing the characteristicsof optical signals caused by nuclear explosions.
In February 1980, CBS News was the first to suggest that Israel helpedSouth Africa conduct a nuclear test. CBS received information from "informedsources," but until now, no South African government official was willingto lend the report any credibility.
Today, Lab scientists are worried that current satellites may have similarcredibility problems in detecting atmospheric tests because of their ages.And for the next generation of satellites, the Pentagon has not decidedwhether budget cuts may affect decisions to place EMP sensors on detectionsatellites to be launched after the year 2000.
The Laboratory and the Department of Energy have spent nearly $50 millionto develop the next generation of sensors and officials are hopeful theywill be included in the payload of future satellites.
Researchers say that because the detection ability for underground andundersea tests is so good, today's rogue nations may choose to conduct clandestineatmospheric nuclear tests which is a good reason to include the EMP sensorson future satellites.
For the 1979 South African test, Los Alamos scientists are convincedthat a functioning EMP detection system on the Vela satellite would haveprovided an unambiguous corroboration of their conclusion: the mystery opticalflash of Sept. 22, 1979, was a nuclear explosion.
Ironically, researchers say, one of the most compelling recommendationsof the 1979 White House panel is, today, in jeopardy of being overlooked.The panel said that because of the ramifications and possible consequencesof nuclear explosions, it is imperative that systems be developed and deployedto provide prompt, reliable corroboration of the evidence.
--Kathy DeLucas