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@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
On Wed, 25 Jul 2001, Tim May wrote:
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
Explosive ablation sounds like giant pulses, and chemicals lasers (the only ones known to provide lasing output in the ballpark) don't do these very well. So either you have to fire synchonously from many platforms, or have a veritable Death Star out there in LEO. Several of them, in fact, to maintain an umbrella at all times.
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.
During boost phase. Once past that, you need a kinetic kill or a nuke to damage a nuke (largely, by neutron flux, not the momentum due to explosive ablation).
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
One would want to hide the real McCoys in metallized inflatable balloons anyway, to hide them in the decoy cloud.
intervals to foil laser frequencies, etc.) that the "punch" method was developed.
Gold or copper will do well for infrared, but aluminizing the hull will still do for a wide spectral window, and I haven't heard about FELs delivering the output necessary.
For knocking out satellites, particle beam weapons are the way to go.
Do you think one could kill a hardened warhead in transit?
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.
It would be interesting to see whether any of the proposed solar power satellites (which need realtime beamforming via a phased array to track the rectenna target on ground) could double as vehicle killers, if deployed massively.
participants (2)
-
Eugene Leitl -
Tim May