The 22 September 1979 Vela Incident—Part II: Radionu- Clide and Hydroacoustic Evidence for a Nuclear Explosion”
SCIENCE & GLOBAL SECURITY ,VOL.,NO.,– https://doi.org/./.. The September Vela Incident: The Detected Double-Flash Christopher M. Wrighta and Lars-Erik De Geer b aUNSW Canberra, School of Physical, Environmental and Mathematical Sciences, Research Group on Science & Security, The Australian Defence Force Academy, Canberra BC, Australia; b(Retired) FOI, Swedish Defense Research Agency, and the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organisation, Flädervägen , Upplands Väsby, Sweden ABSTRACT ARTICLE HISTORY On 22 September 1979 two optical sensors on U.S. satellite Vela Received March 6911 detected a double-flash of light that appeared characteristic Accepted October of an atmospheric nuclear explosion conducted over the south- ern Atlantic or Indian Ocean. It became known as the Vela Inci- dent, Event 747, or Alert 747. An anomaly between the amplitude of the two signals during the second pulse led a U.S. govern- ment expert panel established to assess the event to conclude in mid-1980 that a more likely explanation was the impact of a small meteoroid on the satellite, the debris from which reflected sunlight into the sensors’ field of view. No model was presented to support the contention, and a similar anomaly—known as background modulation—was a given for the second pulse of all confirmed explosions detected by Vela, though beginning later. Nonetheless, this event has remained the subject of intense debate. This article reviews the evidence and presents an updated analysis of the original Vela signal based on recently declassi- fied literature and on modern knowledge of interplanetary dust and hyper velocity impact. Given the geometry of the satellite, and that the bulk of the surface comprised solar panels, much of the debris from any collision would be carried away from the sensors’ field of view.
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