Washington,
DC, May 5, 2006 - Many U.S. government
officials and scientists disagreed with the findings of a presidential
panel that the double flash signal picked up by a U.S. nuclear
detonation detection satellite (Vela 6911) in late September 1979
was possibly not a nuclear test, according to a number of studies
posted today by the National Security Archive.
The signal appeared to come from a 3,000 mile area that included
the South Atlantic, Indian Ocean, tip of Africa, and part of Antarctica.
A presidential panel concluded in May 1980 that the signal was
more likely an artifact of a meteoroid hitting the satellite and
sunlight reflecting off particles ejected as a result of the collision.
In addition to the report of the presidential panel, the posting
includes reports produced by the DCI's Nuclear Intelligence Panel
(completely redacted), and scientists and analysts at Los Alamos,
SRI International, Sandia, the Intelligence Community, the Defense
Intelligence Agency, Mission Research Corporation, and the Aerospace
Corporation. Included are several reports which concluded that
a nuclear test was the most probable explanation of the Vela detection
and/or specifically questioned the presidential panel's explanation.
Many of the reports were obtained under the Freedom of Information
Act by Archive Senior Fellow Jeffrey T. Richelson, while conducting
research for his new book Spying
on the Bomb: American Nuclear Intelligence from Nazi Germany to
Iran and North Korea (W. W. Norton).
The
Vela Incident: Nuclear
Test or Meteoroid?
National
Security Archive Electronic Briefing Book No. 190
Edited
by Jeffrey Richelson
Late in the evening of September 21, 1979 at Patrick Air Force
Base, Florida, technicians from the Air Force Technical Applications
Center (AFTAC), the organization responsible for running the U.S.
Atomic Energy Detection System, conducted a routine readout of
a Vela satellite, designated Vela 6911, which had been launched
on May 23, 1969.
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The Vela-5A/B satellite
(Credit: NASA)
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The first two Velas had been launched in 1963. Vela 6911, which
orbited the earth at an altitude of 67,000 miles, carried a variety
of equipment to detect the numerous signatures associated with
atmospheric nuclear detonations. In addition to sensors to detect
gamma rays, x-rays, and neutrons, the Vela satellite also carried
two bhangmeters - sensors which could detect the light flashes
associated with a detonation, which included an initial brief
but intense flash, and a subsequent, longer lasting flash. (Note
1)
In conducting their readout the AFTAC technicians saw a double
humped signal that corresponded to the double flash associated
with a nuclear explosion. In the 41 previous occurrences when
a Vela satellite detected such a double flash (including the 12
Vela 6911 detections), subsequent data confirmed that a nuclear
detonation had actually occurred. The signal Vela 6911 had apparently
detected came from a remote region of the world, for the territory
in view of its bhangmeters encompassed 3,000 miles in diameter
- the southern tip of Africa, the Indian Ocean, the South Atlantic,
and a bit of Antarctica. The detection took place at about 3:00
a.m. local time, September 22.
The detection raised the possibility that some nation, particularly
South Africa or Israel, or the two in collaboration, had conducted
a covert test. South Africa was believed to have been preparing
for a nuclear test in August 1977 before Soviet and U.S. satellites
detected the preparations, and diplomatic pressure caused the
South Africans to deny any such plan. Israeli-South African cooperation
had been reported in a variety of media sources, although the
specifics were often obscure. (Note 2)
There was a discrepancy in the bhangmeter readings with regard
to the second flash. Because the bhangmeters were not equally
sensitive it was not expected they would produce identical numerical
values. But it was expected that the ratio between the two would
be the same from one detonation to the next. In the case of the
September 22 detection the ratio was not what was expected from
previous experience.
Given the importance of determining if a test had taken place,
and who had conducted a test if it had occurred, the U.S. government
devoted a considerable effort to trying to gather and evaluate
evidence in order to produce definitive conclusions. One component
of this effort involved searching the data already collected by
a variety of U.S. data collection systems at the time of the incident.
Those systems included satellites such as the Defense Support
Program (DSP), Satellite Data System (SDS), and Defense Meteorological
Satellite Program (DMSP) satellites - all of which carried sensors
that could detect some of the signals of a nuclear explosion.
DSP satellites operated in geosynchronous orbit, 22,300 miles
above the earth, and carried sensors that could detect the infrared
(heat) signature of a nuclear detonation, bhangmeters, an x-ray
locator, and an atmospheric fluorescence detector.
Other sensors with the potential to have collected relevant data
included two underwater acoustic arrays - the Sound Surveillance
System (SOSUS) and Missile Impact Location System (MILS), whose
primary missions, respectively, were to monitor Soviet submarines
and to determine where missile test warheads splashed down.
In addition to searching for data that might have been collected
by such sensors, an effort was made to gather data that could
not be collected passively - such as the debris associated with
a very low-yield detonation. While AFTAC sent specially-configured
aircraft to try to gather debris from the region of the apparent
blast, the CIA sent some of its personnel into various nations
in the region to gather the leaves from trees - leaves that might
contain the radioactive residue of an explosion. Such efforts
apparently were futile (although in September 1980 a professor
who had been studying sheep thyroids around the world reported
that iodine-131 [a fission product] had been detected in the thyroids
of sheep slaughtered in Melbourne, Australia in November 1979,
but not subsequently).
Various elements of the government, particularly the Naval Research
Laboratory, also sought out, or were presented with, data that
had been collected as the part of scientific, non-military research.
Included were data from the Arecibo Ionospheric Observatory, as
well as from civilian weather satellites such as Nimbus and Tiros.
Two scientists working at Arecibo detected a traveling ionospheric
disturbance moving in an unusual northward direction at the time
of the Vela detection.
The data accumulated by U.S. and allied intelligence, military,
and civilian agencies, as well as scientific institutions, were
examined by a variety of analysts and organizations - an ad hoc
presidential panel, a DCI panel, the Central Intelligence Agency,
Defense Intelligence Agency, national laboratories such as Los
Alamos and Sandia, as well as organizations under contract to
the Department of Energy and AFTAC.
The conclusions of the presidential panel (the Ad Hoc Panel) were
reassuring, as they suggested that the most likely explanation
of the Vela detection was a meteoroid hitting the satellite -
in part because of the discrepancy in bhangmeter readings. Others
who examined the data, including DIA, the national laboratories,
and contractors reached a very different conclusion - that the
data supported the conclusion that on September 22, 1979 Vela
6911 had detected a nuclear detonation. (Note 3)
Documents
Note:
The following documents are in PDF format.
You will need to download and install the free Adobe
Acrobat Reader to view.
Document
1: Christine Dodson, Staff Secretary, National Security Council,
Memorandum
for: The Secretary of State [and others], Subject: South Atlantic
Nuclear Event, w/att: untitled discussion paper, October
22, 1979. Secret
Source:
Freedom of Information Act Request
This paper was prepared at a time when it was assumed that Vela
6911 had detected a nuclear event - and the limitations of U.S.
knowledge about the South African program permitted the belief
that South Africa was the most likely culprit. The paper explores
the nonproliferation stakes involved, the impact public disclosure
would have on foreign policy efforts in Africa, the pros and cons
of approaching the South African government, the effect on various
nuclear negotiations with South Africa, informing the Soviet Union,
possible U.N. sanctions, and the implications for public perceptions
of the ability to verify a comprehensive test ban treaty.
Document
2: Guy E. Barasch, Los Alamos Scientific Laboratory, Light
Flash Produced by an Atmospheric Nuclear Explosion, November
1979. Unclassified
Source:
Freedom of Information Act Request
In this analysis Barasch examined the possibility that the flashes
detected by the Vela satellite had been the result of a natural
phenomenon. Vela bhangmeters had been triggered hundreds of thousands
of times by lightning, cosmic particles, and direct sunlight.
He concludes that naturally occurring signals would not be confused
with signals from a nuclear detonation, whose light signature
is "unmistakable." In particular, he dismisses the possibility
that the Vela signal came from a lightning "superbolt,"
lightning that is over a hundred times more intense than typical
lightning and usually occurs over water when cold polar air moves
in over warm, moist oceanic air.
Document
3: Director of Central Intelligence, The 22 September
1979 Event, December 1979. Secret
Source:
Freedom of Information Act Request by Natural Resources Defense
Council
This study begins, as was requested by the National Security
Council, with the assumption that the September 22, 1979 Vela
event was a nuclear detonation. It discusses the possibility that
the detonation could have occurred due to an accident, and noted
the Defense Intelligence Agency's suggestion that the Soviet Union
might have had reasons to conduct a covert test in violation of
its treaty commitments. But the majority of the study is concerned
with three possibilities to explain the incident - a secret test
by South Africa, a secret test by Israel, and a secret test by
South Africa and Israel together.
Document
4: Christine Dodson, Staff Secretary, National Security Council,
Memorandum for: The Secretary of State, Subject: Discussion
Paper for Mini-SCC, January 7, 1980, Classification Redacted
Source:
Freedom of Information Act Request
This paper was prepared for a meeting of the "mini"-Special
Coordination Committee. The SCC was established by President Jimmy
Carter's January 20, 1977 Presidential Directive 2, "The
National Security Council System," and was assigned responsibility
for matters such as covert operations, arms control evaluation,
and crisis management. The paper considers the options available
in dealing with three issues: what the United States should say
publicly and privately about the results of its analysis of data
concerning the Vela incident, whether the U.S. should continue
to press for a nuclear agreement with South Africa, and what position
the U.S. should take on nuclear sanctions against South Africa.
Document
5: George N. Oetzel and Steven C. Johnson, SRI International,
Vela Meteoroid Evaluation, January 29, 1980. Secret
Source:
Freedom of Information Act Request
This report resulted from a rush evaluation of the theory that
the Vela double-flash signal was the result of a meteoroid. The
only conclusion they could offer was that proposed scenarios which
involved two meteoroids were likely to produce the Vela signal
only once in one billion years. They also noted that meteoroid
data from the Pioneer space probe suggested other models for meteoroids
producing the signal, but the limited time available for the study
prevented their reaching firm conclusions.
Document
6: Chairman, Joint Atomic Energy Intelligence Committee, Memorandum
for: Director of Central Intelligence, Deputy Director of Central
Intelligence, Subject: Judgments of the DCI's Nuclear Intelligence
Panel on the 22 September 1979 Event, February 14, 1980.
Secret w/att: Judgments of the DCI's Nuclear Intelligence
Panel on the 22 September 1979 Event, n.d. Secret
Source:
Freedom of Information Act Request
Shortly after the Vela incident, Director of Central Intelligence
Stansfield Turner asked his Nuclear Intelligence Panel, chaired
by Donald Kerr, who had served in the Carter administration as
acting director of defense programs at the Energy Department,
to examine the data relating to the incident. According to the
February 14, 1980 memorandum to the DCI, the panel reviewed data
from the event on February 11-13, 1980. The facts and discussion
contained in the attached report were completely redacted from
the report before it was released in response to a Freedom of
Information Act Request. According to Seymour Hersh's The
Samson Option, Kerr stated "We had no doubt it was a
bomb." (Note 4)
Document
7: Henry G. Horak, Los Alamos Scientific Laboratory, Vela
Event Alert 747, May 1980. Secret
Source:
Freedom of Information Act Request
Among the issues addressed by Horak in his paper is why the bhangmeters
on two Defense Support Program (DSP) satellites which could receive
signals from the South Atlantic area - DSP 6 and DSP 7 - did not
trigger. He offers two explanations: the event did not take place
within the satellite's field of view or the signal was weakened
by transmission through clouds and was not strong enough to reach
the necessary brightness threshold for detection. He concluded
that after looking at all the data associated with the signal,
there was "strong evidence that a nuclear explosion actually
produced Vela Alert 747."
Document
8: G.H. Mauth, Sandia National Laboratories, Alert 747,
May 1, 1980. Secret
Source:
Freedom of Information Act Request
In his report Mauth notes that of all the satellites equipped
with bhangmeters, which included the Vela, DSP, and Satellite
Data System spacecraft, only Vela 6911 detected the double flash
associated with a nuclear detonation. He also disputes, based
on laser calibration tests, the hypothesis in the Mission Research
Corporation study (Document 11) that the
different bhangmeter readings could be explained by a malfunction.
However, based on his analysis of all the data available to him
he concluded that the Vela signal was "fully consistent with
those expected from a low-yield atmospheric [nuclear detonation]."
Document
9: Office of Science and Technology Policy, Ad Hoc Panel
Report on the September 22 Event, May 23, 1980. Secret
Source:
Freedom of Information Act Request
Following the Vela detection President Jimmy Carter asked Dr.
Frank Press, his science adviser, to establish a panel of outside
experts. The Ad Hoc Panel that Press formed was chaired by Dr.
Jack Ruina, a former head of the Defense Department's Advanced
Research Projects Agency, and included Richard Garwin, Luis Alvarez,
and Wolfgang Panofsky among its members. The panel was asked to
review classified and unclassified data that could help determine
whether the Vela signals had been the result of a nuclear detonation,
to consider the possibility that the signal was a "false
alarm" resulting from a satellite malfunction, and to investigate
whether the signal was the result of one or more natural phenomena.
After three meetings, which included hearing presentations from
the Defense Intelligence Agency, the Naval Research Laboratory,
and other organizations, the panel completed its work and issued
its report. Based on the discrepancy in bhangmeter readings, and
the construction of what the panel considered a plausible alternative
- which involved a meteoroid colliding with the Vela satellite
and ejecting some particles which reflected sunlight into the
field of view of the bhangmeters - the panel concluded that the
Vela signal was probably not the result of its having detected
a nuclear detonation.
Document 10:
John E. Mansfield and Houston T. Hawkins, Defense Intelligence
Agency, The South Atlantic Mystery Flash: Nuclear or Not?,
June 26, 1980. Secret
Source:
Freedom of Information Act Request
The authors of this paper included a Harvard Ph.D. in physics
(Mansfield) and a lieutenant colonel (Hawkins) who had recently
joined DIA as head of the Nuclear Energy Division's Nuclear Weapons
Branch. The authors noted much of the search for corroborating
evidence of a nuclear detonation on September 22 had failed, and
that while there were a number of signals that might be considered
as corroborating evidence, those signals were weak, embedded in
noise, or represented a phenomenon that was not well understood.
Among the topics they examined were the absence of detected radioactivity,
the traveling ionospheric disturbance, and the possibility that
one or more micrometeoroids caused the Vela signal. They proceeded
to offer an explanation of how radioactivity might not have been
detected despite a detonation, calculated that the probability
of northward ionospheric disturbance occurring at the same as
the Vela event was extremely low (not more than 0.02), and concluded,
based on the calculation of Stanford Research Institute scientists
(see Document 5), that the probability of
a single meteoroid causing the Vela signal was less than one in
one hundred billion.
When news of the study appeared in The New York Times
and The Washington Post, the White House released an
only mildly-redacted copy of the Ad Hoc Panel Report.
Document
11: D.S. Sappenfeld, D.H. Sowle, and T.H. McCartor, Mission
Research Corporation, Possible Origins of Event 747 Optical Data,
August 1980. Secret
Source:
Freedom of Information Act Request
This paper, prepared under contract to the Air Force Technical
Applications Center, was an expanded version of an earlier paper
of the same title that had been completed in December 1979. The
authors reached the same conclusion that they had nine months
earlier - that the likelihood that Vela had detected a nuclear
detonation was much higher than the probability of any nonnuclear
explanation for the triggering of the bhangmeters. They also concluded
that the data indicated a surface detonation and that there were
serious flaws in the Ad Hoc Panel's meteoroid theory.
Document
12: E.W. Hones Jr., D.N. Baker, and W.C. Feldman, Los
Alamos Scientific Laboratory, Evaluation of Some Geophysical Events
on 22 September 1979, April 1981. Unclassified
Source: Freedom of Information Act Request
The authors report on their analysis of data obtained by the
TIROS-N weather satellite on September 22, 1979. They had sought
to determine whether an electron precipitation event detected
by the satellite could have been related to a surface nuclear
burst (SNB). They concluded that the event was "unusually
large" but not unique. On the other hand, they found no data
that were inconsistent with the occurrence of a SNB. In addition,
the authors note that "a patch of auroral light that suddenly
appeared in the sky near Syowa Base, Antarctica a few seconds
after the Vela event can be interpreted (though not uniquely)
as a consequence of the electromagnetic pulse of an SNB."
Document
13: C.J. Rice, Aerospace Corporation, Search for Correlative
Data, January 15, 1982. Secret
Source:
Freedom of Information Act Request
This study was performed by the Aerospace Corporation, whose
mission was to provide technical support and analysis to NRO and
the Air Force, for the Air Force Systems Command. The author focused
on the infrared data obtained by two DSP satellites (Flights 6
and 7) whose footprints overlapped that of Vela 6911. Ultimately,
no confirmation of a test could be found. While at least one signal
merited special attention, it was insufficiently intense and was
considered very unlikely to represent a nuclear event.
Document
14: E.M. Jones, R.W. Whitaker, H.G. Horak, and J.W. Kodis,
Los Alamos National Laboratory, Low-Yield Nuclear Explosion
Calculations: The 9/22/79 VELA Signal, May 1982
Source:
Freedom of Information Act Request
In their study, the four Los Alamos scientists discounted a variety
of explanations for the discrepancies in the bhangmeter readings,
including atmospheric absorption of the signal or cloud cover.
They went on to present their own model for the September 22 event,
a model that remains largely classified but may have relied on
the effect of surface bursts on bhangmeter readings. It does seem
likely that the authors shared the belief of many of their colleagues
at Los Alamos and Sandia that the September 22 event was a nuclear
test. They wrote that "our model is consistent with the apparent
absence of nuclear debris, the collection of which is required
by some analysts for absolute confirmation of an atmospheric detonation."
Document
15: Gerald S. Wright, Air Force Technical Applications Center,
History of the Air Force Technical Applications Center, 1
January 1979 - 31 December 1980, Volume I, Narrative (Excerpt),
May 17, 1982. Secret
Source:
Freedom of Information Act Request
This extract from an AFTAC history describes some of the collection
effort that followed the Vela detection. According to AFTAC historian
Gerald Wright the detection "set off one of the most extensive
air sampling operations in recent years."
Notes
1. This section is based on Jeffrey T. Richelson, Spying
on the Bomb: American Nuclear Intelligence from Nazi Germany to
Iran and North Korea (New York: W.W. Norton, 2006), pp.
283-316.
2. For example, see James Adams, The Unnatural Alliance
(London: Quartet, 1984).
3. The Naval Research Laboratory also conducted a study, which
has never been declassified. The study concluded that the Vela
6911 signal most probably resulted from a nuclear detonation.See
Richelson, Spying
on the Bomb, pp. 306-310.
4. Seymour Hersh, The Samson Option: Israel's Nuclear Arsenal
and American Foreign Policy (New York: Random House, 1991),
pp. 280-281.
