DSP observation of aircraft collision - was Mid-air collision

Philip Chien (kc4yer@amsat.org)
Sun, 21 Sep 1997 00:10:28 -0400

catching up on the mail ...

Bruno Tilgner <Bruno_Tilgner@compuserve.com> said:

>According to the news, a South-African satellite has recorded a flash
>which might have been caused by the mid-air collision between an American
>and a German military aircraft off the coast of Namibia a few days ago.

The only South-African satellite is SunSat, an amateur radio satellite
which is still on the ground.  It's scheduled for launch as a piggyback
with ARGOS some time next year.

My guess is this is a garbled report about a satellite which observed the
collision off the coast of Africa.

Bruno Tilgner <Bruno_Tilgner@compuserve.com>

>It was an American satellite which observed the flash last
>Saturday. It would still be interesting which satellite it was.
>Presumably one of those designed to detect missile launches and nuclear

Based on the description it was almost certainly one of the DSP-647
(Defense Support Program) satellites.  These satellites are infrared
telescopes with a line of mercury-cadnium telluride detectors.  The
satellite spins creating radar-like images.  While they were originally
intended to monitor strategic missile launches (e.g. Soviet ICBMs) they've
also been used to monitor tactical short-range missiles (e.g. Iraqi Scuds)
and even satellite reentries.

An artist's rendition of DSP is featured on the cover of the July-August
issue of "Satellite Times".  The DSP satellites are featured in part 2 of a
three part series on the USA series of military satellites. Modesty
prevents me from mentioning the name of the author of that series.

Robert G Fenske Jr <fenske@rgfpc.electro.swri.edu> said:

>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).

The Vela (Spanish for 'Watchman') satellites are still in orbit, but no
longer in operation.  The GPS satellites have nuclear detectors.  The GPS
II-R satellites have crossed-Yagi log periodic antennas which are rather
distinctive in the illustrations.  And the obvious advantage to GPS is
you've got several satellites over the horizon at any given moment over
every portion of the Earth, which pretty much ensures that no nuclear event
could occur without it being detected.

>  Back in the
>'70s these satellites had detected flashes near S. Africa, leading to
>controversial speculation that S. Africa had developed the nuclear bomb.

The South African government recently admited that they actually did test
the BOMB which was detected by the VELAs, there was a pretty good story in
Aviation Week.

However, I can understand why the data was suspect at the time.  It was a
pretty good coincidence that a VELA was in orbit at the right place when
the test took place, its sensors had aged, and there were no pieces of
other evidence which would indicate that the test took place.  For me it
was rather shocking to find out that the test had actually taken place.

Philip Chien [M1959.05.31/31.145//KC4YER@amsat.org]