Lasers and ICBMs

[Tim May]

Being older than most of you, I remember doing some of these 
calculations about burn times, laser intensities, etc. more than 20 
years ago. (Although Reagan did not announce SDI until around 1983, 
the topic was widely discussed in the late '70s. "Scientific 
American" published articles by Prof. Kosta Tsipis, Richard Garwin, 
and others about the difficulty of intercepting ICBMs with lasers and 
particle beams. I remember some of these articles from circa 1977-79. 
I even used one of the them as the basis for a presentation I made to 
DARPA in Washington on a kill method for satellites.)

A lot of the calculations being sketched out here, of watts/cm^2, 
dwell times, gold coatings, etc. are slightly off-base. We've known 
for 20+ years that the kill method is to use a short pulse to "push" 
(not from the photons' momentum) in the thin wall of an ICBM's fuel 
system. A very short pulse can produce enough ablative heating, a 
kind of "puff," to trigger buckling of the very thin wall of an ICBM.

So the theory goes. Countermeasures to traditional "heating" are so 
easy to imagine (rapidly spinning the missile, deploying gold-plated 
shrouds once exoatmosheric, changing the missile coating at random 
intervals to foil laser frequencies, etc.) that the "punch" method 
was developed.

I'm still skeptical, for the reasons many have outlined over the 
years. Bill Stewart, most recently, who pointed out that the 
Macedonian Liberation Army will simply smuggle in a bomb and then 
demand that the U.S. and NATO stop arming the Albanian terrorists. 
And so on.

For knocking out satellites, particle beam weapons are the way to go. 
And don't believe Kosta Tsipis' 1978-79 article in Sci Am about how 
50 loads of fuel in the space shuttle would be needed for every 
firing of a particle beam weapon.

--Tim May

-- 
Timothy C. May         tcmay at got.net        Corralitos, California
Political: Co-founder Cypherpunks/crypto anarchy/Cyphernomicon
Technical: physics/soft errors/Smalltalk/Squeak/agents/games/Go
Personal: b.1951/UCSB/Intel '74-'86/retired/investor/motorcycles/guns