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Missile Defense

Russian military leaders have expressed concern about US plans for a national missile defense system. Will defense technology be limited by possibilities for a strategic imbalance? Is this just SDI all over again?

rshowalter - 12:15pm Jul 7, 2001 EST (#6733 of 6738)
Robert Showalter showalte@macc.wisc.edu

The reservations on the basis of energy (not energy per unit time -- the total energy it actually takes, concentrated, to do real damage) remain as well -- rshowalter 7/6/01 8:55pm

So do the issues of distortion. Would better mirrors reduce distortion problems? Sure.

But not far enough, for mirrors anyone is anywhere close to getting to a tactically useful stage.

There are also mixing problems on the lasar -- as a repeater -- I wonder how many multiple shot tests there really are.

rshowalter - 12:51pm Jul 7, 2001 EST (#6734 of 6738)
Robert Showalter showalte@macc.wisc.edu

Note that I have agreed that the Garwin proposal for a close in, smart rock, boost phase intercept was feasible, and maybe a good idea, if one thinks the threat is worth the resources, and can't be adressed in other ways.

http://www.fas.org/rlg/20.htm

http://www.armscontrol.org/ACT/sept00/bpisept00.html

MD6676 gisterme 7/6/01 12:16pm ... MD6677 rshowalter 7/6/01 12:19pm
MD6680 rshowalter 7/6/01 12:53pm ... MD6681 gisterme 7/6/01 12:56pm
MD6683 rshowalter 7/6/01 1:03pm ... MD6688 rshowalter 7/6/01 1:16pm

The lasar programs are something else entirely -- and the easiest, and most basic arguments against them depend on understanding what resolution is -- something nicely illustrated in nice links from Dawn on the Hubble Space Telescope http://www.astrophys.org/high_2001.html

MD6690 rshowalter 7/6/01 1:46pm MD6691 rshowalter 7/6/01 1:48pm

gisterme asked a key question, that illustrated a key body of misunderstandings in MD6695 gisterme 7/6/01 3:10pm .. which includes this:

" The rocket plume is like a giant infrared arrowhead pointing directly at the rocket saying "here I am...shoot me!". It's about 3 orders of magnitude larger than the headlight and perhaps 4 orders of magnitude brighter. Why wouldn't that be orders of magnitude easier to detect, track and aim at than the one or two headlights in the example that you've given?

It is a reasonable question, reasonably asked, but a revealing question, too. People in the lasar program should, long since, have been clear about the answer.

In postings since, I've provided answers that I believe are entirely correct so far as they go. One could say

" Yes, Bob, the theory you set out is OK, but we're much farther along than you think --- you can't know that, and we can't tell you exactly why -- because our results are classified."

We can discuss that.

My position is that I trust what I can check , and when direct checking isn't possible -- connections to what can be checked need to be constructed.

On question is not "what has been drawn, and made into a pretty picture?" -- but "what has worked when it has been tested?"

My understanding, as of now, is that not much has been tested. Indeed, considering the money spent, shockingly little. And that little, often, dressed up to be more than it is.

gisterme - 01:58pm Jul 7, 2001 EST (#6735 of 6738)

smartalix wrote: "...Regarding a rotating missile during launch, why would it be impossible?

Few things would seem to be impossible , smartalix but spinning an ICBM that needs to be guided to a very specific trajectory to release its MIRV bus would seem impractical. Remember that the inertial navigaion system for an ICBM controls a vectored thrust rocket. That guidance system needs to give constant feedback to the thrust vectoring system to assure that the booster is on just the right trajectory at the instant of payload release. That would also require the entire rocket and payload to have symmetry of mass along the thrust axis. It would need to be spin-balanced just like a tire.

WRT gyros, they follow the same rules regardless of their scale (MEMS) or implementation method (fiber-optic). You may know something about MEMS technology that I don't, I'm certainly no expert, but I havn't heard of any gyros built at that scale or sensor systems that could usably detect torques from something that small. Please fill me in if you do, I'd be delighted to to know. WRT fiber-optic gyros, they would appear to have some advantages over mechanical gyros but they still have to emulate them to be useful in an inertial navigation system. Tumbling the gyro's "stable plane" on the equivalent axis of rotation would still be a problem. If you are an expert on this then please explain why such tumbling would not cause a problem. How strong are the N. Koreans, Iraqis or Iranians in those technologies? I'll bet they'd be pushing their limits to get scud-like accuracy in an ICBM.

Spinning the rocket body about the gyro-stabilized (not spinning) reference platform, or electronically simulated stable platform used for inertial guidance wouldn't be impossible but even with modern control systems keeping the thrust vectoring accurate would not be a trivial problem. Remember that the entire rocket becomes a gyroscope if you spin it. Great for travelling in a straight line but not so good for steering to a precise vector. It would seem that spinning the rocket would severely compound the guidance problem.

"... I see a second-generation (anti-ABM) booster spinning like a gyrojet slug..."

Where do you see that, smartalix?

"...Why not a rotating missile?..."

See above. Probably not impossible but probably would require a complete re-design of ICBMs and their guidance systems. Not likely affordable for a country like N. Korea and not necessary for countries like Russia or even China that could launch more than a few ICBMs at once.

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