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Re: LF: Re: Alarming message

To: <[email protected]>
Subject: Re: LF: Re: Alarming message
From: "Hugh_m0wye" <[email protected]>
Date: Wed, 23 Aug 2006 12:05:06 +0100
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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

 



From: [email protected] [mailto:[email protected]] On Behalf Of Andre Kesteloot
Sent: 22 August 2006 16:14
To: [email protected]
Subject: Re: LF: Re: Alarming message

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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