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Missile Defense

Technology has always found its greatest consumer in a nation's war and defense efforts. Since the last attempts at a "Star Wars" defense system, has technology changed considerably enough to make the latest Missile Defense initiatives more successful? Can such an application of science be successful? Is a militarized space inevitable, necessary or impossible?

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rshow55 - 06:56am Feb 11, 2002 EST (#11477 of 11481)

Just got up and had some coffee. This thread can't converge, left to itself, but it does have some of the characteristics of pre-trial discovery, where salient arguments and fact do get set out -- for later validation. And sometimes, key arguments converge. We've been talking a good deal about the airborne laser http://airbornelaser.com/special/abl/description/ , a very expensive system for which a lot is being claimed.

Some key assumptions were set out by gisterme in MD11199 gisterme 2/3/02 12:36am

"The fallacy of your argument is the assumption is that the beam is perfectly parallel or that it diverges. Using adaptive optics of the type described for the ABL means that the beam can be focused to converge to a point at any arbitrary distance. That's why they'd need to know the exact range to the target. So the beam that starts out 24" in diameter can be focused to a much smaller point at the target.

"If the beam is focused to say a 10cm diameter at the target, and you've lost half the transmitted energy due to absorption, you've still got 1 magawatt applied to an area of about 79 cm^2. That's 12.7 kW/cm^2 for 100% absorption, 254 W/cm^2 for 2% absorption and 25.4 W/cm^2 for .2% absorption. Oh, by the way, there's no reason that the beam couldn't be focused into an even smaller area, say about the size of your fingernail.

The numbers and assumptions behind them matter.

In MD11420 mazza9 2/10/02 5:05pm . . . the claim's made that " A laser has absolutely perfect optical characteristics. "

Perfect to do the job a laser pointer has to do, or a laser printer laser has to do, or an optical fiber laser has to do - - - maybe - - maybe perfect in the sense of "perfect for the job."

But

Lasers work because light organizes itself, by reflections between mirror surfaces, coherently -- not perfectly in the mathematical sense, but with the waves close to perfect phase. If the cosine of the angle by which the mirrors depart from parallel is approximately 1, the lasing works.

The angular accuracy lasing needs is much less than the level of angular accuracy needed so that optical imperfections in the laser can be ignored for the purposes of ABL. MD11439 rshow55 2/10/02 7:05pm

Could the people proposing and working on ABL have missed this? If they have, perhaps they are acting in good faith -- perhaps they feel that the mirror adjustment job, alone, may be sufficient for ABL, after billions of dollars of work not yet done. But they have made a fatal mistake.

Are they assuming that they can make, and maintain under tactical conditions, a chemical laser, with a high power output, that has optical parallelism of not very many nanoradians, without adaptive optics adjustment of the laser assembly itself? And assuming that they can have this working on a vibrating airplane, subject to the shocks and vibrations (usually moderate, but real) airplane passengers riding Boeing 747s experience?

Even if this were possible -- and it doesn't seem to be, and if it is, it takes a feat -- a technical miracle - - how many b other "just barely possible" things do these MD programs have to do all together, at the same time? MD11424 rshow55 2/10/02 5:23pm

This isn't an effort to defend America -- - not a realistic one. It is, at best, workfare for contractors - - contractors who could, and should, be doing something useful --- not wasting taxpayers money, and misinforming military decision makers who need weapons that work.

rshow55 - 06:59am Feb 11, 2002 EST (#11478 of 11481)

This is no "rational investment for America." It is a sucker bet - which weakens the United States. If this sort of project is "hard to kill" -- then we have the national equivalent of a cancer - - with "cells" growing out of control, soaking up resources, and crowding out healthy growth.

Not all cancers kill -- not for a long time. But they weaken. And they are very dangerous.

Military decision making as irresponsible as this is very dangerous, too. To say that the people making these decisions are "loyal Americans" -- would that be reasonable? I can only think so, if I think they are making mistakes - - and mistakes that they are willing to correct.

It is enronation - - but soaking up resources from the federal revenue, rather than from the private sector. So it is enronation without the natural limits of the free market. - - Enronation still, presenting bad bets, for the profit of insiders, on the basis of grossly false information - - incorectly and ornately presented -- again and again, in many ways, with the intention to deceive.

rshow55 - 11:06am Feb 11, 2002 EST (#11479 of 11481)

I trust we're agreed on what adaptive optics is? MD11369 rshow55 2/8/02 6:12pm

I fee that this schematic diagram of the process involved in adaptive optics is very good, and I hope people look at it carefully. I hope we can agree that this schematic, and language connected to it, are well grounded references helping to define what adaptive optics is http://cfao.ucolick.org/images/aos_small.gif

( To get a bigger, clearer image of http://cfao.ucolick.org/images/aoscheme.gif . ... )

lchic - 12:53pm Feb 11, 2002 EST (#11480 of 11481)

Within amorphous organisations some projects
start-up and then take on a life of their own.
The history, rational, and reasoning are lost
as the initiators move on
abandoning these ever-funded,
now orphaned projects.

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