The Vela Flash: Forty Years Ago

Since its creation during the Kennedy administration, the White House Situation Room has functioned as a communications center and a site for holding sensitive meetings. This record of situation room interactions with various agencies concerning the 22 September event provides an overview of the delayed and unsuccessful efforts to detect the radioactive debris that a nuclear test could have produced. The excised portions are probably a reference to the Air Force Technical Applications Center [AFTAC], which under various names has been monitoring overseas nuclear developments since the late 1940s and which played a role in the search for radioactive samples in the South Pacific after the Vela Incident..

Even though AFTAC found no traces of fallout, analysis of thyroid glands of sheep slaughtered in Australia in October 1979 showed "abnormally high levels" of Iodine 131, a "short-lived isotope that occurs as the result of a nuclear event."

Writing to Ambassador-at-Large Henry Owen, who had overlapping roles at the White House and the State Department, John Deutch sent a report of a “traveling ionospheric disturbance”—a wave in the upper atmosphere—detected by the Arecibo Observatory, a giant radio telescope nestled into the mountains of Puerto Rico. According to Deutch, the data on the ionospheric disturbance “possibly may confirm the signal from the VELA system.”

The Arecibo Observatory (now a National Science Foundation facility) can detect signals in the upper atmosphere that originate in violent events at Earth’s surface—including volcanic eruptions, earthquakes, nuclear explosions, and even rocket launches. Such events can produce strong sound waves of very low frequency (pitch), far below what the human ear can detect (the periods of these waves are measured in minutes or longer, as opposed to thousandths of seconds for humanly audible sound). These waves propagate upward through the atmosphere. When they reach the ionosphere, a layer of electrically charged particles beginning about 80 kilometers (50 miles) above Earth, they may induce so-called traveling ionospheric disturbances (TIDs).

The Arecibo Observatory is one of the best instruments in the world for observing TIDs. It does conventional radio astronomy for studying the cosmos, but it also sends powerful radar beams into the upper atmosphere to probe Earth’s ionosphere. Several hours after the VELA flash detection, Arecibo observed a TID. Initially downplayed in part because of Aricebo’s location thousands of miles from the VELA event, the observation produced a different perspective from DOE, which suggested that the TID was consistent with “an earthquake or explosion source” and that the wave speed was consistent with an event having come from the VELA source—although ambiguities in the exact type (mode) of the wave made a shorter distance also possible. The available declassified information notes that similar observations (although pre-Arecibo) have been associated with nuclear tests in the Soviet arctic in 1961.

The Department of Energy’s Los Alamos Laboratory developed its thinking on the Arecibo signal, treating it as a possible indicator of a nuclear event. Nevertheless, the Ruina panel would discount the Arecibo data on grounds of “mathematical errors,” although the defense and energy departments strongly disagreed. Pending declassification requests may shed more light on the debate over the Arecibo data.

According to national security adviser Zbigniew Brzezinski’s aides, a panel organized by White House science adviser Dr. Frank Press and chaired by MIT professor Jack Ruina was already reviewing data and heading toward a “preliminary finding” that the Vela flash was not a nuclear event. According to the early findings, “it is entirely possible that the September 22 signal could have been caused by a meteroid of somewhat different velocity, size and rotational motion.” Moreover, the Vela signal “itself differs in some important ways from previous nuclear signals.” Without corroborating data, “these facts tended to make the panel somewhat skeptical that a nuclear explosion actually occurred.”

The report also mentioned Deutch’s report on the newly interpreted data from the Arecibo Observatory. While noting that the Arecibo data “has a very different timescale” and that the “relationship between nuclear explosions and ionospheric disturbances is much less well understood than for optical signals recorded by bhangmeters [on VELA satellites],” it “represents the best lead yet in the search for corroborative data.”

On 9 January 1980, a “mini-SCC [Special Coordinating Committee]” meeting discussed the 22 September event. According to participants, “The consensus was that we don't know what happened, and must proceed in policy terms accordingly.” The effort to politicize science is implicit. In a way, that conclusion matched the findings of the Ruina panel. Agnostic semi-official conclusions notwithstanding, important elements of the intelligence community continued to hold that a nuclear event had been detected, as evidenced in a report included in the National Security Archive’s 2016 posting.

This report conveys the approach that senior White House staff took toward dissenting views on the 22 September event. A scheduled presentation by representatives of the Departments of Energy and Defense would provide an opportunity for them to express arguments that a nuclear event had occurred; they would be heard out, according to this memo, “so that we can more safely ignore them.” This can arguably be seen as another possible demonstration of a “whitewash” effort to politicize scientific evidence.

According to Oplinger’s memorandum, the CIA’s "Safeguards-D" report had “assessed the probability of a nuclear test as 90% plus.” The Safeguards-D report was one required by the U.S. Senate when it ratified the Limited Test Ban Treaty in 1963. Consistent with proposals by the Joint Chiefs of Staff that the treaty be ratified on the basis of specific conditions, the Senate required the Kennedy administration to take specific implementing actions, such as recommendation D: “The improvement of our capability, within feasible and practical limits, to monitor the terms of the treaty, to detect violations, and to maintain our knowledge of Sino-Soviet nuclear activity, capabilities, and achievements.”

Having heard rumors that the CIA wanted to rewrite its safeguards report so that it corresponded to the findings of the Ruina panel, Oplinger wanted to make sure that CIA did no such thing because “nothing would suggest a whitewash more effectively.” If the CIA later decided that it wanted to update the earlier report that would be another matter as long as it could “provide solid and objective reasons.”

In this memorandum to Director of Central Intelligence Stansfield Turner, Frank Press, White House science adviser, explained the reasoning behind the Ruina panel’s conclusion that the Vela flash was “probably not from a nuclear explosion” and “more likely … caused by a natural event.” He could not have written to Turner, however, without acknowledging the dissents expressed by “key officials” at the Defense Intelligence Agency, the CIA’s Nuclear Intelligence Panel (NIP), and the DOE weapons laboratories, who believed that the Vela signal detected a nuclear event. According to Press, “this is due primarily to the fact that the signal so closely resembles those from previous nuclear explosions, but the weapons laboratories have been unable to come up with a physical explanation that could explain the discrepancies observed in the signal.”

Press also noted that some of the agencies point to the “few pieces of geophysical data from September 22 that might have been related to a nuclear explosion.” He most likely referred to Arecibo data, and quite possibly also to the acoustic signals as analyzed by the naval Research Laboratory. Nevertheless, Press discounted it all: the data had “been thoroughly analyzed and none can be clearly correlated with the VELA signal.” We do not know if CIA Director Turner responded in writing to this memorandum. In the late 1990s, Turner told one of us (Avner Cohen) that he (and the Agency) had no doubt that it was a test and almost certainly an Israeli test.

Believing that White House scientists were not acting in good faith, by the spring of 1980, DIA experts saw the nuclear interpretation as settled in light of Naval Research Laboratory acoustic data that had not been available to the CIA or the Ruina panel. According to a senior DIA official, the acoustic signals were “unique to nuclear shots in a maritime environment.’”