Hi Andy,
I don't quite know where EMP crept into
the discussion.
Dick's original E-mail to this reflector
was about a paper on Radiation Belt Remediation.
http://www.physics.otago.ac.nz/research/space/ag-24-2025.pdf
This was suggesting using large amounts
of VLF to "drain" the artifical radiation belts produced by a High
Altitude Nuclear Explosion.
The paper was suggesting that the
radiation belts would damage low earth orbit satelites - based on the
observations of such damage found in the 1960s. I quote ...
"The effect of the Starfish Prime HANE on the radiation belts was
observed by multiple spacecraft. However, the intense artificial belts injected
by the HANE damaged 3 of the 5 satellites operating at the time. Within a small
number of days, data transmissions from the Ariel, Transit IVB and TRAAC
satellites became intermittent or ceased altogether (Massey, 1964), primarily
due to degrading solar cells. Other effects were also noted even in this early
case; the transistors flown in the first active communications satellite,
Telstar, failed due to radiation exposure, even though the satellite was
launched after the Starfish Prime HANE."
I was suggesting that modern
semiconductor devices and circuit design might be more immune to this kind of
radiation damage, so the need for "remediation" might not be as great as was
suggested in the paper.
73
Hugh M0WYE
----- Original Message -----
Sent: Wednesday, August 23, 2006 10:14
AM
Subject: RE: LF: Re: Alarming
message
My understanding of EMP Nuclear bombs - gained from
documentation from the 1960s/70s, was that these were exo-atmospheric bursts
designed to generate huge impulses at the ground due to Compton scattering of
electrons blasted down from the upper atmosphere.
Tests ( on BikiniAtol ?) caused severe disruption
to electronic equipment hundreds to thousands of km away, and are even reputed
to have knocked out streetlights at those sorts of
distances.
I don't see how satellites well above the atmosphere
could be disrupted by such an event. Direct satelite damage was very
difficult to produce then due to the difficulties of getting close enough -
even a 1MT bomb probably has to be within less than a kilometre of a satellite
for its direct radiation to be high enough to damage the electronics (no blast
damage in space !) Satellites are designed to withstand high radiation
levels from the sun. Rember the huge programme of Star Wars
started in the '80's. Nowadays such close positioning would be
easier, of course.
So it looks as if satcoms would survive, whereas HF and
ground based electronics would not. SRI, fellow amateurs hoping
for a return to HF!
All info gained from open literature
;-)
Andy G4JNT
Hugh_m0wye wrote:
3. The
supposed disruption to satelites caused by a HANE seems to be based on what
happened to Telstar and similar vintage space-craft. Surely satelite design
has progressed since then, with better shielding and "radiation hardened"
devices being used. If satelites are more robust then much of the reason for
using RBR evaporates.
It could be
that the concerns may be over the possibility of a North Korean missile sent
in space to create an EMP and wiping out satellite communications
There is
a difference between space equipment being "radiation-hardened" against the
radiations normally found in space, and the neutrons. etc, that could be
created by a nuclear device exploded in space.
73
André
N4ICK
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