Vela detection of South Afr

17 Sep 1997 12:47:17 -0800

Robert Fenske recently wrote, in response to the possible observation of the
collision flash over Africa:

"... At one time, the U.S. had several Vela satellites in orbit that were
designed to look for missile launches and/or nuclear detonations.  I don't
have a clue as to whether these satellites are still in operation (or even in
orbit).  Back in the '70s these satellites had detected flashes near S.
leading to controversial speculation that S. Africa had developed the nuclear

About 2 months ago, the South African deputy foreign minister, Aziz Pahad,
confirmed that his nation did indeed detonate an above-ground nuke in
September, 1979, thus finally vindicating the Vela 6911 observation of a flare
of bright light over the Indian Ocean on September 22, 1979.  According to
Aviation Week & Space Technology, July 21, 1997, "It was immediately reported
as a suspected nuclear detonation, but, because optical data were not
corroborated by other information, the Carter White House vigorously
challenged military and nuclear laboratories' analyses.  That position was
based on a general mistrust of aging satellites, and a refusal to accept
supporting data from other sources."  The article goes on to say, "Six pairs
of Vela satellites were orbited between 1963-70, with each vehicle carrying
sensors to detect nuclear explosions in the atmosphere and in space.  Designed
at the Los Alamos and Sandia national laboratories, two optical
sensors--called Bhangmeters--were tailored to detect intense but brief light
pulses characteristic of nuclear detonations (AW&ST Aug. 11, 1980, p. 67). The
satellites also carried electromagnetic pulse detectors."

"Typically, one of the optical sensors detected more light than the other,
which complicated data interpretation.  Vela 6911 also was operating beyond
its seven-year design life--which cast doubt on the optical data--and its EMP
sensor was inoperative, precluding a corroborating electromagnetic signature
from being obtained.  The Carter panel claimed the flash could have been
caused by natural events, such as a micrometeorite impact on the detector
sunshade.  However, intelligence and laboratory officials were not convinced."

I found the history of this story very interesting, particularly all the
effort that the Air Force and the intelligence community went to in order to
find corroborating data.  Aircraft searching for airborne fission product
samples, seismic and hydroacoustic network data searches, and even a traveling
ionospheric disturbance detected at Arecibo.  --Rob