# The 1979 Vela incident > At 00:52:43 UTC on 22 September 1979 the US satellite Vela 6911 recorded the double flash of light that marks an atmospheric nuclear explosion, somewhere… Source: https://mysteriesdept.com/mysteries/vela-incident Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) Updated: 2026-10-27T17:48:30+00:00 --- **MYS** 0CW4WNP04GV8·Mystery · event # The 1979 Vela incident **0** [Follow][Ask a question](https://mysteriesdept.com/questions/key-questions?mystery=vela-incident) The 1979 Vela incident ![The Vela 5A and 5B satellites before launch.](https://mysteriesdept.com/media/folio/vela-incident-lead) Los Alamos National Laboratory · Attribution Detected 22 September 1979, 00:52:43 UTC, by Vela 6911 (Alert 747)⁠[[3]] Sensors Two bhangmeters (YCA and YVA) recording a double flash⁠[[1]] Region South Atlantic or southern Indian Ocean; Prince Edward Islands area favoured from hydroacoustics⁠[[3]] Estimated yield A few kilotons; about 1–2 kt from the timing of the flash⁠[[1]] Official review OSTP Ad Hoc (Ruina) Panel, 23 May 1980: probably not a nuclear explosion⁠[[7]] Leaked Reported by ABC TV on 25 October 1979⁠[[3]] Suspected tester Israel, possibly with South Africa (not acknowledged)⁠[[4]] Status Partly explained Questions 0 of 4 answered People [**Christopher M. Wright** Australian scientist; co-author of the 2017 and 2018 analyses](https://mysteriesdept.com/mysteries/vela-incident/people/FIG0CW4WRKR53JZ/christopher-m-wright)[**Jack Ruina** MIT professor, former ARPA director; chaired the White House panel](https://mysteriesdept.com/mysteries/vela-incident/people/FIG0CW4WQ4W4PFG/jack-ruina)[**Lars-Erik De Geer** Swedish scientist; co-author of the 2017 and 2018 analyses](https://mysteriesdept.com/mysteries/vela-incident/people/FIG0CW4WRBY391S/lars-erik-de-geer)[**Jimmy Carter** US President, 1977–1981](https://mysteriesdept.com/mysteries/vela-incident/people/FIG0CW4WQMG44TY/jimmy-carter)[**Lester VanMiddlesworth** University of Tennessee (Memphis) scientist who measured iodine-131 in sheep thyroids](https://mysteriesdept.com/mysteries/vela-incident/people/FIG0CW4WR4416YG/lester-vanmiddlesworth) All 7 people › [**Richard L. Garwin** IBM physicist; Ruina panel member](https://mysteriesdept.com/mysteries/vela-incident/people/FIG0CW4WQCP28M0/richard-l-garwin)[**Alan Berman** Director of the Naval Research Laboratory in 1979](https://mysteriesdept.com/mysteries/vela-incident/people/FIG0CW4WQWA2DDM/alan-berman) Catalog key**MYS** 0CW4WNP04GV8 From 1963 the United States launched Vela satellites into orbit to watch for nuclear explosions banned by the Partial Test Ban Treaty⁠[[1]]. Each carried bhangmeters, photodiodes that recognise the unique light of an atmospheric nuclear burst: a millisecond flash, a dip as the fireball's shock front hides the core, and a second, longer peak that carries most of the energy⁠[[2]]⁠[[1]]. Just before 1 a.m. UTC on 22 September 1979, both bhangmeters on Vela 6911, a satellite then about ten years old, recorded that double flash from somewhere over the South Atlantic or southern Indian Ocean⁠[[3]]⁠[[4]]. A month later the National Security Council recorded the Intelligence Community's "high confidence" that a low-yield atmospheric nuclear explosion had occurred⁠[[5]]. The finding was politically difficult. The suspects were South Africa, Israel, or both together⁠[[6]], and an Israeli test would have raised hard questions for the Carter administration soon after the Egypt-Israel peace treaty⁠[[4]]. A panel of outside scientists convened by the White House and chaired by Jack Ruina reported in May 1980 that the signal was "probably not from a nuclear explosion", because the two bhangmeters disagreed in part of the second peak, and suggested light reflected from debris knocked off the satellite by a meteoroid⁠[[7]]. The Defense Intelligence Agency, Los Alamos, Sandia and the Naval Research Laboratory disagreed⁠[[8]]⁠[[9]]⁠[[10]]⁠[[4]]. Declassified documents, released through the National Security Archive from 2006 on, and two papers by Lars-Erik De Geer and Christopher Wright in 2017 and 2018 have since rebuilt the case. They argue that the bhangmeter discrepancy has an ordinary explanation in an ageing satellite, that a meteoroid is very unlikely, that hydrophones near Ascension Island recorded an explosion-like signal from the direction of the Prince Edward Islands at the right time, and that iodine-131 in Australian sheep thyroids fits fallout carried east from there⁠[[1]]⁠[[3]]. The official record has not caught up: no government has acknowledged a test, and the NRL hydroacoustic report remains classified⁠[[3]]⁠[[11]]. Of the 4 questions on this site, 0 are answered. The most likely answer to “If it was a test, who conducted it?”, not yet confirmed: israel, possibly with South African help or territory. ### Key questionsset by the editors [**If it was a test, who conducted it?** ](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WYQ270JZ/if-it-was-a-test-who-conducted-it)Most likely: israel, possibly with South African help or territory [**Was the signal of 22 September 1979 a nuclear explosion?** ](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WXZM2TV0/was-the-signal-of-22-september-1979-a-nuclear-explosion)Most likely: a low-yield atmospheric nuclear test of a few kilotons, near the ocean surface [All 4 questions ](https://mysteriesdept.com/questions/key-questions?mystery=vela-incident) ## What happened At 00:52:43 UTC on 22 September 1979 Vela 6911 recorded the signal designated Alert 747. The Air Force Technical Applications Center, which runs US nuclear-detection systems, began an extensive search for corroboration, including air sampling over the Southern Hemisphere⁠[[3]]⁠[[12]]. At 02:43 UTC hydrophones near Ascension Island recorded an impulsive signal that, traced back along the ocean's sound channel, implied an origin close to the time of the flash⁠[[3]]. On 22 October the NSC reported high confidence in a nuclear explosion⁠[[5]]; on 25 October ABC Television broke the story⁠[[3]]. [![First page of NSC memorandum of 22 October 1979 with the discussion paper on the South Atlantic event](https://mysteriesdept.com/files/v/51be4696376cf1e13ecd739b654e2da6f8c4284f809237c4eee8f955a9f9aceb/p1)12 pages](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XEB20ZJQ/nsc-memorandum-of-22-october-1979-with-the-discussion-paper) NSC memorandum of 22 October 1979 with the discussion paper on the South Atlantic eventNational Security Council, 1979. Public domain[Artifact ](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XEB20ZJQ/nsc-memorandum-of-22-october-1979-with-the-discussion-paper) The government studies divided. A CIA-sponsored panel in October 1979 found the signals consistent with a nuclear explosion⁠[[4]]. Richard Garwin, soon to sit on the White House panel, wrote on 19 October that he would bet 2 to 1 on a nuclear explosion; he later changed his view⁠[[4]]. An SRI evaluation of January 1980 found two-meteoroid scenarios would produce such a signal about once in a billion years⁠[[13]]. The Ruina panel's report of 23 May 1980 concluded the signal was probably not nuclear⁠[[7]]. The CIA's Nuclear Intelligence Panel reviewed the data in February 1980; its judgments were released fully redacted⁠[[14]]. Los Alamos, Sandia, the DIA and an AFTAC contractor concluded that it probably was⁠[[9]]⁠[[10]]⁠[[8]]⁠[[15]]. A DIA official called the White House report a "whitewash" influenced by "political considerations"⁠[[4]]. **Map of the world** [Open the full map](https://mysteriesdept.com/mysteries/vela-incident/map) [+][−] 1 **Syowa Station, Antarctica** Research station Within 1 km 2 **Prince Edward Islands (Marion and Prince Edward), South Africa** Sub-Antarctic islands Within 10 km 3 **Melbourne, Victoria (abattoir supplying the thyroid samples)** City Within 10 km 4 **Ascension Island hydrophone array** Hydroacoustic station Within 10 km 5 **Argentia, Newfoundland (SOSUS station)** Hydroacoustic station Within 10 km 6 **Wilson Center, Washington DC** Research centre Within 100 m 7 **The White House, Washington DC** Government office Within 100 m MappedWithin 1 kmA regionNatural Earth ### Timeline **Timeline** Squeezed where little happened. Each mark is a published claim, by how it stands:AcceptedMost likelyStill possibleDisputedRuled out ## The accounts President Carter wrote in his diary on 22 September 1979 that there was an indication of a nuclear explosion in the region of South Africa, by South Africa, by Israel using a ship at sea, "or nothing"; on 27 February 1980 that "we have a growing belief among our scientists that the Israelis did indeed conduct a nuclear test explosion in the ocean near the southern end of South Africa"⁠[[4]]⁠[[11]]. Zbigniew Brzezinski expressed a similar view to a biographer in 2016⁠[[11]]. In November 2019 the Wilson Center, the Middlebury Institute and the National Security Archive held a critical oral history conference with surviving participants: Ruina panel members Garwin and Richard Muller, NSC staff, State Department, CIA and Energy officials, Senate staffer Leonard Weiss, the CBS correspondent who reported Israeli involvement in 1980, and the analysts De Geer and Wright. Alan Berman, director of the NRL in 1979, sent a statement explaining why the hydroacoustic data persuaded him a nuclear detonation had occurred near the Prince Edward Islands⁠[[11]]. The organisers note that some participants were constrained by continuing classification⁠[[11]]. ## What was recorded The optical record is two bhangmeter traces. They agree closely through the first pulse and the minimum, and diverge in the second pulse; the Ruina panel took the divergence as evidence against a nuclear source⁠[[7]]. Wright and De Geer show that Vela 6911's memory fault had cut off the second half of its bhangmeter records for every test it saw from July 1972 to March 1978, so there was no like-for-like comparison, and that a similar second-pulse effect, background modulation, appears in all confirmed tests⁠[[1]]. The timing of the minimum (5 ms) and second maximum (53 ms) gives yields of about 1 to 2 kilotons by the empirical scaling laws⁠[[1]]. The traces and the comparison signals remain with AFTAC; the published copies are plots in declassified reports and in the 2017 paper⁠[[7]]⁠[[1]]. [![First page of Vela 6911 bhangmeter records of Alert 747 (YCA and YVA traces)](https://mysteriesdept.com/files/v/2c25bfa96f15f37c0a36e171590f7a046c770de7223bb9dc9f0e1d8d1d252322/p1)20 pages](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XAE2734B/vela-6911-bhangmeter-records-of-alert-747-yca-and-yva-traces) Vela 6911 bhangmeter records of Alert 747 (YCA and YVA traces)Office of Science and Technology Policy Ad Hoc Panel, 1979. Public domain[Artifact ](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XAE2734B/vela-6911-bhangmeter-records-of-alert-747-yca-and-yva-traces) The hydroacoustic record is held by the US Navy. A team of up to 75 NRL staff analysed it in a report of several hundred pages sent to the White House on 30 June 1980. According to that study as summarised in a declassified letter of 11 December 1980 from the NRL's research director, three hydrophones near Ascension Island recorded at 02:43 UTC a signal more than 300 times the noise, on a bearing of 198 ± 10 degrees and with dispersion implying a path of about 10,000 km; a second station at Argentia, Newfoundland, also recorded it after a reflection from Antarctica⁠[[3]]. The NRL report itself remains classified⁠[[3]]. The radionuclide record is a set of sheep thyroids. Since 1956, thyroids from sheep slaughtered in Melbourne had been sent monthly to Lester VanMiddlesworth at the University of Tennessee for iodine-131 measurement. Samples slaughtered in late October and early November 1979 showed iodine-131, for example about 1.9 ± 0.6 pCi/g corrected to slaughter for one sample. VanMiddlesworth's notebooks are at the Nuclear Testing Archive in Las Vegas and some documents at the National Security Archive; De Geer and Wright published three of his gamma spectra⁠[[3]]. Other possible correlates, an electron-precipitation event seen by TIROS-N and a patch of aurora seen from Syowa Station in Antarctica seconds after the flash, are suggestive but not unique⁠[[16]]. Defense Support Program satellites with overlapping coverage did not trigger⁠[[9]]. ## The explanations A low-yield nuclear test is the explanation most of the technical studies reached. The double flash is the signature for which the system was built, and the bhangmeters' first pulses agree with each other and with earlier tests⁠[[1]]. Los Alamos and Sandia analysts in 1980 judged the signal consistent with a low-yield atmospheric burst, and a 1982 Los Alamos model fitted it as one while accounting for the absence of collected debris⁠[[9]]⁠[[10]]⁠[[17]]. De Geer and Wright add the hydroacoustic signal at the right time and bearing and the iodine-131 carried to south-eastern Australia by a plume that met rain there on 26 September, and estimate a yield of a few kilotons near the ocean surface, with most debris rained out locally by a passing storm⁠[[3]]. Who tested is a separate question. The CIA's December 1979 assessment, assuming a test, weighed South Africa, Israel, and both together⁠[[6]]. The 2016 documents show that US officials had sought and received Israeli denials of nuclear-weapons cooperation with South Africa in 1977, and that a later State Department report recounted the NRL finding of a source near the South African-held Prince Edward Islands⁠[[4]]. The editors of the 2016 posting conclude that a test, most likely Israeli and possibly with South African help, is the stronger reading⁠[[4]]. [![First page of The OSTP Ad Hoc Panel report on the September 22 event (Ruina panel)](https://mysteriesdept.com/files/v/2c25bfa96f15f37c0a36e171590f7a046c770de7223bb9dc9f0e1d8d1d252322/p1)20 pages](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XDBT7TZF/the-ostp-ad-hoc-panel-report-on-the-september-22-event-ruina) The OSTP Ad Hoc Panel report on the September 22 event (Ruina panel)Office of Science and Technology Policy, 1980. Public domain[Artifact ](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XDBT7TZF/the-ostp-ad-hoc-panel-report-on-the-september-22-event-ruina) [![First page of "The South Atlantic Mystery Flash: Nuclear or Not?" (DIA paper)](https://mysteriesdept.com/files/v/e73ec49d4a4cd51b439b7d09f04cdef67a99cb005fea7b0d2faf109130d1f723/p1)54 pages](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XDVE25J6/the-south-atlantic-mystery-flash-nuclear-or-not-dia-paper) "The South Atlantic Mystery Flash: Nuclear or Not?" (DIA paper)Defense Intelligence Agency, 1980. Public domain[Artifact ](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XDVE25J6/the-south-atlantic-mystery-flash-nuclear-or-not-dia-paper) A non-nuclear event near the satellite is the official alternative. The Ruina panel judged the meteoroid explanation "reasonable" but did not claim it was correct, and did not compute the probability of a nuclear explosion⁠[[7]]⁠[[3]]. Against it, the SRI study put two-meteoroid scenarios at about once in a billion years, the DIA put a single-meteoroid cause at under one in a hundred billion, and Wright and De Geer found that most debris from an impact on the satellite's solar panels would travel away from the sensors' field of view⁠[[13]]⁠[[8]]⁠[[1]]. A sensor malfunction remains possible in principle for an aged satellite, and the panel noted the absence of "persuasive corroborative evidence"⁠[[3]]. ### Published claims **Published claims and their status** | Year | Who | Claimed | Status | Reason | |---|---|---|---|---| | 1979 | CIA-sponsored scientists' panel⁠[18] | The Vela signals are consistent with a nuclear explosion. | Accepted | Every later re-analysis of the optical data by the weapons laboratories and in the open literature reached the same view⁠[15]⁠[1] | | 1979 | US Intelligence Community, via the National Security Council⁠[5] | There is high confidence that a low-yield atmospheric nuclear explosion took place on 22 September 1979. | Accepted | The double flash, the Ascension hydroacoustic signal and the iodine-131 in Australian sheep thyroids all point to a test, though no fission debris was collected⁠[1]⁠[3]⁠[4] | | 1979 | Director of Central Intelligence⁠[6] | If the event was a nuclear test, South Africa, Israel or the two together are the most likely to have conducted it. | Most likely | Later documents and testimony narrowed the reading towards Israel, possibly with South African help, though neither state has acknowledged a test⁠[4]⁠[11] | | 1980 | George Oetzel and Steven Johnson (SRI International)⁠[13] | A meteoroid strike producing the Vela signal would happen about once in a billion years. | Accepted | The DIA reached a still smaller figure, and the satellite's geometry sends most debris away from its sensors⁠[8]⁠[1] | | 1980 | Office of Science and Technology Policy panel chaired by Jack Ruina⁠[7] | The signal was probably not from a nuclear explosion, and light from meteoroid debris knocked off the satellite is a reasonable alternative. | Disputed | The bhangmeter difference it relied on matches background modulation seen in confirmed tests, and laser calibration found the sensors working⁠[1]⁠[10] | | 1980 | Sandia National Laboratories (G. H. Mauth)⁠[10] | Laser calibration tests show the bhangmeters were working, so their differing readings do not make the signal false. | Accepted | The 2017 re-analysis of the optical record agrees⁠[1] | | 1980 | John Mansfield and Houston Hawkins (Defense Intelligence Agency)⁠[8] | The flash was nuclear; the chance of a single-meteoroid cause is under one in a hundred billion. | Accepted | It agrees with the SRI meteoroid evaluation and with the later optical re-analysis⁠[13]⁠[1] | | 1980 | D. S. Sappenfeld and D. H. Sowle⁠[15] | A nuclear surface burst is much more likely than any non-nuclear trigger of the bhangmeters, and the meteoroid theory has serious flaws. | Accepted | Its conclusion is borne out by the 2017 re-analysis of the double flash⁠[1] | | 1991 | Seymour Hersh⁠[19] | Former Israeli officials say the flash was an Israeli test of a low-yield nuclear artillery shell, one of three such tests. | Most likely | It fits Carter's diary and the 2016 editors' reading, but it rests on unnamed sources and Israel has never acknowledged a test⁠[11]⁠[4] | | 1997 | Aziz Pahad⁠[20] | There was definitely a nuclear test in 1979, and the bomb was South African. | Still possible | He later said he had not made the statement, and the claim has not been substantiated⁠[20] | | 2015 | Leonard Weiss⁠[21] | The flash was most likely an Israeli nuclear test carried out with South African logistical help, and the US government covered it up. | Most likely | It agrees with the declassified record and the 2016 editors' judgement, though key documents remain classified⁠[4] | | 2017 | Christopher Wright and Lars-Erik De Geer⁠[1] | The double flash matches confirmed nuclear tests, and the bhangmeter difference is ordinary background modulation, not a fault. | Accepted | It rests on the full optical record of earlier tests, and no published rebuttal has appeared⁠[1] | | 2018 | Lars-Erik De Geer and Christopher Wright⁠[3] | Iodine-131 in Melbourne sheep thyroids and the hydroacoustic signal at Ascension both trace to a nuclear explosion near the Prince Edward Islands. | Most likely | The trajectory and timing fit, but air sampling in Australia and New Zealand found nothing and the thyroid detector was criticised at the time⁠[3] | ## What would settle it Declassification would settle most of it. The NRL hydroacoustic report and its data, the full bhangmeter records with the comparison events used by the Ruina panel, and the AFTAC air-sampling results would allow an independent analysis of each strand; two Carter Library files on the event remained classified in 2016 and had been requested for review⁠[[4]]. Physically, a search of the seabed and island soils near the Prince Edward Islands for long-lived fission products or plutonium with a weapons isotopic signature would test the location. Archival records of naval movements in the area in September 1979 would test the means of delivery. ## Questions 0 of 4 questions are answered. **Key questions** [All 4](https://mysteriesdept.com/questions/key-questions?mystery=vela-incident) **0** [If it was a test, who conducted it?](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WYQ270JZ/if-it-was-a-test-who-conducted-it) 0 of 0 sub-questions answered·0 Most likely: israel, possibly with South African help or territory **0** [Was the signal of 22 September 1979 a nuclear explosion?](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WXZM2TV0/was-the-signal-of-22-september-1979-a-nuclear-explosion) 0 of 2 sub-questions answered·0 Most likely: a low-yield atmospheric nuclear test of a few kilotons, near the ocean surface ## Evidence 28 findings [Was the signal of 22 September 1979 a nuclear explosion?](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WXZM2TV0/was-the-signal-of-22-september-1979-a-nuclear-explosion)15 findings [A low-yield atmospheric nuclear test of a few kilotons, near the ocean surface.](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4WYYW57H0/a-low-yield-atmospheric-nuclear-test-of-a-few-kilotons-near)Most likely +[The first pulses of both bhangmeters agree with each other and with earlier tests; the second-pulse difference resembles background modulation seen in all confirmed tests.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4WZ6P3YE9/the-first-pulses-of-both-bhangmeters-agree-with-each-other)Supported +[Ascension hydrophones recorded an impulsive signal at 02:43 UTC on a bearing and path consistent with an origin near the Prince Edward Islands at the flash time.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4WZEG1TB9/ascension-hydrophones-recorded-an-impulsive-signal-at-02-43)Supported +[Iodine-131 in thyroids of sheep slaughtered in Melbourne in October and November 1979, consistent with a plume meeting rain on 26 September.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4WZPA7CGD/iodine-131-in-thyroids-of-sheep-slaughtered-in-melbourne-in)Suggestive +[Los Alamos and Sandia analysts judged the signal consistent with a low-yield atmospheric burst.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4WZY47GE3/los-alamos-and-sandia-analysts-judged-the-signal-consistent)Supported +[The NSC recorded the Intelligence Community's high confidence in a low-yield explosion on 22 October 1979.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X05Y3KBE/the-nsc-recorded-the-intelligence-communitys-high-confidence)Suggestive −[No fission debris was collected by AFTAC air sampling, and New Zealand rainwater data proved a false alarm.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X0DR74RH/no-fission-debris-was-collected-by-aftac-air-sampling-and)Supported −[Defense Support Program satellites with overlapping coverage did not trigger.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X0NJ0F0D/defense-support-program-satellites-with-overlapping-coverage)Suggestive [A small meteoroid struck the satellite and sunlight reflected from the ejected debris into the bhangmeters.](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X0XC3N6F/a-small-meteoroid-struck-the-satellite-and-sunlight)Disputed +[The bhangmeters disagreed in part of the second pulse, which the panel had not seen in earlier tests.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X1562SC0/the-bhangmeters-disagreed-in-part-of-the-second-pulse-which)Suggestive +[The panel called the debris explanation reasonable but did not claim it was correct.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X1D073DE/the-panel-called-the-debris-explanation-reasonable-but-did)Speculative −[Two-meteoroid scenarios would produce such a signal about once in a billion years.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X1MT26S5/two-meteoroid-scenarios-would-produce-such-a-signal-about)Supported −[The DIA put the chance of a single-meteoroid cause at under one in a hundred billion.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X1WM3DAY/the-dia-put-the-chance-of-a-single-meteoroid-cause-at-under)Suggestive −[Given the satellite's geometry and solar panels, most impact debris would move away from the sensors' field of view.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X24E0K8R/given-the-satellites-geometry-and-solar-panels-most-impact)Supported [A malfunction or unexplained false signal of an aged satellite, unrelated to any explosion.](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X2C84Q4H/a-malfunction-or-unexplained-false-signal-of-an-aged)Disputed +[Vela 6911 had a memory fault from 1972 to 1978 and was beyond its design life.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X2M27N12/vela-6911-had-a-memory-fault-from-1972-to-1978-and-was)Suggestive −[The first pulse of Alert 747 is inconsistent with the few hundred unexplained signals from which the panel suggested it was drawn.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X2VW424P/the-first-pulse-of-alert-747-is-inconsistent-with-the-few)Suggestive −[Laser calibration tests showed the bhangmeters operating nominally.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X33P2S9R/laser-calibration-tests-showed-the-bhangmeters-operating)Suggestive [Did the hydroacoustic signal come from the same event as the flash?](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WY7E4HGQ/did-the-hydroacoustic-signal-come-from-the-same-event-as-the)4 findings [The Ascension and Argentia signals came from an explosion near the Prince Edward Islands at the flash time.](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X3KA5093/the-ascension-and-argentia-signals-came-from-an-explosion)Most likely +[Signal at SNR over 300, bearing 198 ± 10 degrees, path about 10,000 km, origin time about 00:52 UTC.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X3V438MV/signal-at-snr-over-300-bearing-198-10-degrees-path-about-10)Supported +[Fine structure matched hydroacoustic signals from French atmospheric tests in the Pacific.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X42Y4940/fine-structure-matched-hydroacoustic-signals-from-french)Suggestive +[Alan Berman, NRL director, stated the data persuaded him of a detonation near the Prince Edward Islands.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X4AR1WY4/alan-berman-nrl-director-stated-the-data-persuaded-him-of-a)Suggestive [The signal had another source, natural or man-made, and its timing is coincidental.](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X4JJ2KT7/the-signal-had-another-source-natural-or-man-made-and-its)Still possible +[The Ruina panel judged the hydroacoustic evidence not persuasive.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X4TC0435/the-ruina-panel-judged-the-hydroacoustic-evidence-not)Speculative [Was the iodine-131 in Australian sheep thyroids fallout from the event?](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WYF84TRD/was-the-iodine-131-in-australian-sheep-thyroids-fallout-from)5 findings [The iodine-131 came from a test near the Prince Edward Islands, carried east and rained out over…](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X5A032M1/the-iodine-131-came-from-a-test-near-the-prince-edward)Most likely +[One sample slaughtered 22 October gave about 1.9 ± 0.6 pCi/g corrected to slaughter; three spectra show iodine-131's lines.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X5HT1EE4/one-sample-slaughtered-22-october-gave-about-1-9-0-6-pci-g)Suggestive +[A NOAA and NRL trajectory from near Marion Island passes south-eastern Australia on 26 September, when it rained in the sheep-grazing areas.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X5SM0AVJ/a-noaa-and-nrl-trajectory-from-near-marion-island-passes)Suggestive −[Air-sampling networks in Australia and New Zealand detected nothing.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X61E5Q7X/air-sampling-networks-in-australia-and-new-zealand-detected)Suggestive [The readings were background, contamination or measurement error.](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X69827MZ/the-readings-were-background-contamination-or-measurement)Disputed +[VanMiddlesworth's first reading in November 1979 found no abnormal radioactivity.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X6H25TP6/vanmiddlesworths-first-reading-in-november-1979-found-no)Suggestive +[Ruina panel member Wolfgang Panofsky wrote that the thyroid detector was unshielded and triggered by passers-by.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X6RW4VDY/ruina-panel-member-wolfgang-panofsky-wrote-that-the-thyroid)Speculative [If it was a test, who conducted it?](https://mysteriesdept.com/mysteries/vela-incident/questions/QST0CW4WYQ270JZ/if-it-was-a-test-who-conducted-it)4 findings [Israel, possibly with South African help or territory.](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X78G2VTN/israel-possibly-with-south-african-help-or-territory)Most likely +[Carter recorded in February 1980 a growing belief among US scientists that Israel had tested.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X7GA0HCA/carter-recorded-in-february-1980-a-growing-belief-among-us)Suggestive +[The 2016 editors judge an Israeli test, possibly with South African assistance, the more likely reading.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X7R4770W/the-2016-editors-judge-an-israeli-test-possibly-with-south)Speculative −[Israel gave the United States categorical denials of nuclear-weapons cooperation with South Africa in 1977.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X7ZY65BM/israel-gave-the-united-states-categorical-denials-of-nuclear)Speculative [Another state, such as a covert Soviet test.](https://mysteriesdept.com/mysteries/vela-incident/answers/ANS0CW4X8FJ2T8D/another-state-such-as-a-covert-soviet-test)Still possible +[The DCI assessment noted the DIA's suggestion that the Soviet Union might have had reasons for a covert test.](https://mysteriesdept.com/mysteries/vela-incident/evidence/EVD0CW4X8QC157F/the-dci-assessment-noted-the-dias-suggestion-that-the-soviet)Speculative ## Artifacts The films, photos, papers and objects this mystery rests on, each with its own key and its distance from the original. **Artifacts** [See all 13](https://mysteriesdept.com/mysteries/vela-incident/artifacts) Document2 steps from object [Vela 6911 bhangmeter records of Alert 747 (YCA and YVA traces)](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XAE2734B/vela-6911-bhangmeter-records-of-alert-747-yca-and-yva-traces) Office of Science and Technology Policy Ad Hoc Panel · Public domain (US government work) Document2 steps from object [Naval Research Laboratory hydroacoustic report on the 22 September 1979 event](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XB5G4N7C/naval-research-laboratory-hydroacoustic-report-on-the-22) Robert A. Martin, State Department Bureau of Intelligence and Research · Public domain (US government work) Document2 steps from object [Thyroid glands of sheep slaughtered in Melbourne, October–November 1979, and their gamma spectra](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XBDA1RR4/thyroid-glands-of-sheep-slaughtered-in-melbourne) Lars-Erik De Geer and Christopher M. Wright · publisher Photo1 step from object [The OSTP Ad Hoc Panel report on the September 22 event (Ruina panel)](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XDBT7TZF/the-ostp-ad-hoc-panel-report-on-the-september-22-event-ruina) Office of Science and Technology Policy · Public domain (US government work) Photo1 step from object ["The South Atlantic Mystery Flash: Nuclear or Not?" (DIA paper)](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XDVE25J6/the-south-atlantic-mystery-flash-nuclear-or-not-dia-paper) Defense Intelligence Agency · Public domain (US government work) Photo1 step from object [NSC memorandum of 22 October 1979 with the discussion paper on the South Atlantic event](https://mysteriesdept.com/mysteries/vela-incident/artifacts/ART0CW4XEB20ZJQ/nsc-memorandum-of-22-october-1979-with-the-discussion-paper) National Security Council · Public domain (US government work) [See all 13 artifacts](https://mysteriesdept.com/mysteries/vela-incident/artifacts) ## See also [ **Roswell, 1947** Debris found near Roswell, New Mexico, in 1947 and announced as a flying disc. ](https://mysteriesdept.com/mysteries/roswell) [ **1908 Tunguska event** An explosion over the Siberian taiga in 1908 that flattened 2,150 km² of forest. ](https://mysteriesdept.com/mysteries/tunguska-event) [ **Younger Dryas impact hypothesis** A 2007 proposal that a comet exploded over North America and began the Younger Dryas. ](https://mysteriesdept.com/mysteries/younger-dryas-impact) [ **US government UAP disclosures** US government reports, files and testimony on unidentified anomalous phenomena. ](https://mysteriesdept.com/mysteries/uap-us-government) ## References 1. 1.[Wright, C., De Geer, L. 2017. The 22 September 1979 Vela Incident: The Detected Double-Flash. Science & Global Security 25(3), 95–124.](https://mysteriesdept.com/sources/SRC0CW4WMPR4HES/the-22-september-1979-vela-incident-the-detected-double)[doi](https://doi.org/10.1080/08929882.2017.1394047)cited 9 times here**SRC** 0CW4WMPR4HES 1. 2.[Barasch, G. 1979. Light Flash Produced by an Atmospheric Nuclear Explosion. National Security Archive Electronic Briefing Book 190, Document 2.](https://mysteriesdept.com/sources/SRC0CW4WHH64DDQ/light-flash-produced-by-an-atmospheric-nuclear-explosion)cited 1 time here**SRC** 0CW4WHH64DDQ 1. 3.[De Geer, L., Wright, C. 2018. The 22 September 1979 Vela Incident: Radionuclide and Hydroacoustic Evidence for a Nuclear Explosion. Science & Global Security 26(1), 20–54.](https://mysteriesdept.com/sources/SRC0CW4WMYJ4E2N/the-22-september-1979-vela-incident-radionuclide-and)[doi](https://doi.org/10.1080/08929882.2018.1451050)cited 30 times here**SRC** 0CW4WMYJ4E2N 1. 4.[Burr, W., Cohen, A. 2016. Vela Incident: South Atlantic Mystery Flash in September 1979 Raised Questions about Nuclear Test. National Security Archive and Nuclear Proliferation International History Project, posted 8 December 2016.](https://mysteriesdept.com/sources/SRC0CW4WMEY25SX/vela-incident-south-atlantic-mystery-flash-in-september-1979)cited 12 times here**SRC** 0CW4WMEY25SX 1. 5.[Dodson, C. 1979. South Atlantic Nuclear Event (memorandum with untitled discussion paper). National Security Archive Electronic Briefing Book 190, Document 1.](https://mysteriesdept.com/sources/SRC0CW4WH9C1ECW/south-atlantic-nuclear-event-memorandum-with-untitled)cited 6 times here**SRC** 0CW4WH9C1ECW 1. 6.[Director of Central Intelligence 1979. The 22 September 1979 Event. National Security Archive Electronic Briefing Book 190, Document 3.](https://mysteriesdept.com/sources/SRC0CW4WHS01J09/the-22-september-1979-event)[doi](https://doi.org/10.1515/9783112557167)cited 6 times here**SRC** 0CW4WHS01J09 1. 7.[Office of Science and Technology Policy (panel chaired by Jack Ruina) 1980. Ad Hoc Panel Report on the September 22 Event. National Security Archive Electronic Briefing Book 190, Document 9.](https://mysteriesdept.com/sources/SRC0CW4WK021RSG/ad-hoc-panel-report-on-the-september-22-event)cited 13 times here**SRC** 0CW4WK021RSG 1. 8.[Mansfield, J., Hawkins, H. 1980. The South Atlantic Mystery Flash: Nuclear or Not?. National Security Archive Electronic Briefing Book 190, Document 10.](https://mysteriesdept.com/sources/SRC0CW4WK7W0YTX/the-south-atlantic-mystery-flash-nuclear-or-not)cited 6 times here**SRC** 0CW4WK7W0YTX 1. 9.[Horak, H. 1980. Vela Event Alert 747. National Security Archive Electronic Briefing Book 190, Document 7.](https://mysteriesdept.com/sources/SRC0CW4WJGE03ET/vela-event-alert-747)cited 2 times here**SRC** 0CW4WJGE03ET 1. 10.[Mauth, G. 1980. Alert 747. National Security Archive Electronic Briefing Book 190, Document 8.](https://mysteriesdept.com/sources/SRC0CW4WJR805GV/alert-747)cited 2 times here**SRC** 0CW4WJR805GV 1. 11.[Cohen, A., Burr, W. 2020. Revisiting the 1979 VELA Mystery: A Report on a Critical Oral History Conference. Wilson Center, Sources and Methods blog, posted 31 August 2020.](https://mysteriesdept.com/sources/SRC0CW4WN6C7XSV/revisiting-the-1979-vela-mystery-a-report-on-a-critical-oral)cited 11 times here**SRC** 0CW4WN6C7XSV 1. 12.[Richelson, J. 2006. The Vela Incident: Nuclear Test or Meteoroid?. National Security Archive Electronic Briefing Book No. 190, posted 5 May 2006.](https://mysteriesdept.com/sources/SRC0CW4WM74286K/the-vela-incident-nuclear-test-or-meteoroid)cited 3 times here**SRC** 0CW4WM74286K 1. 13.[Oetzel, G., Johnson, S. 1980. Vela Meteoroid Evaluation. National Security Archive Electronic Briefing Book 190, Document 5.](https://mysteriesdept.com/sources/SRC0CW4WJ0T4Q9A/vela-meteoroid-evaluation)cited 2 times here**SRC** 0CW4WJ0T4Q9A 1. 14.[Chairman, J. 1980. Judgments of the DCI's Nuclear Intelligence Panel on the 22 September 1979 Event. National Security Archive Electronic Briefing Book 190, Document 6.](https://mysteriesdept.com/sources/SRC0CW4WJ8M0ATR/judgments-of-the-dcis-nuclear-intelligence-panel-on-the-22)cited 1 time here**SRC** 0CW4WJ8M0ATR 1. 15.[Sappenfeld, D., Sowle, D., McCartor, T. 1980. Possible Origins of Event 747 Optical Data. National Security Archive Electronic Briefing Book 190, Document 11.](https://mysteriesdept.com/sources/SRC0CW4WKFP6R03/possible-origins-of-event-747-optical-data)cited 1 time here**SRC** 0CW4WKFP6R03 1. 16.[Hones, E., Baker, D., Feldman, W. 1981. Evaluation of Some Geophysical Events on 22 September 1979. National Security Archive Electronic Briefing Book 190, Document 12.](https://mysteriesdept.com/sources/SRC0CW4WKQG5BPK/evaluation-of-some-geophysical-events-on-22-september-1979)[doi](https://doi.org/10.2172/6419744)cited 1 time here**SRC** 0CW4WKQG5BPK 1. 17.[Jones, E., Whitaker, R., Horak, H. et al. 1982. Low-Yield Nuclear Explosion Calculations: The 9/22/79 VELA Signal. National Security Archive Electronic Briefing Book 190, Document 14.](https://mysteriesdept.com/sources/SRC0CW4WKZA3JS8/low-yield-nuclear-explosion-calculations-the-9-22-79-vela)cited 1 time here**SRC** 0CW4WKZA3JS8 1. 18.[Cowey, R. 1979. Memorandum for the Files (synopsis of the CIA scientists' panel on the South Atlantic event). National Security Archive, Nuclear Vault, 8 December 2016 posting, Document 10.](https://mysteriesdept.com/sources/SRC0CW4WPDE63W6/memorandum-for-the-files-synopsis-of-the-cia-scientists)cited 1 time here**SRC** 0CW4WPDE63W6 1. 19.[Hersh, S. 1991. The Samson Option: Israel's Nuclear Arsenal and American Foreign Policy. Random House, New York.](https://mysteriesdept.com/sources/SRC0CW4WQ4W3PHP/the-samson-option-israels-nuclear-arsenal-and-american)cited 1 time here**SRC** 0CW4WQ4W3PHP 1. 20.[Venter, A. 1997. Re-examine nuke test. Mail & Guardian, 23 October 1997.](https://mysteriesdept.com/sources/SRC0CW4WQCP1B6K/re-examine-nuke-test)cited 1 time here**SRC** 0CW4WQCP1B6K 1. 21.[Weiss, L. 2015. Flash from the past: Why an apparent Israeli nuclear test in 1979 matters today. Bulletin of the Atomic Scientists, 8 September 2015.](https://mysteriesdept.com/sources/SRC0CW4WQMG7XPC/flash-from-the-past-why-an-apparent-israeli-nuclear-test-in)cited 1 time here**SRC** 0CW4WQMG7XPC Last edited 27 Oct 2026