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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?

Read Debates, a new Web-only feature culled from Readers' Opinions, published every Thursday.

gisterme - 03:14pm Feb 11, 2002 EST (#11482 of 11486)

rshow55 2/11/02 6:56am

"...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..."

You still haven't posted a reference to show the basis for this claim, Robert. You were given the benefit of the doubt and politely asked to provide a reference...just like a referee, umpire or judge might do. What's the holdup?

As you say, numbers and assumptions are important. Assumptions without some supporting documentation are pretty much just feelings. So if your statement is just your feeling then be honest and say so. If not, present some checkable information to support your statment.

Otherwise don't base conclusions on unsupported statements or ask others who may not have enough technical knowledge to judge for themselves to believe your feeling is a fact. By doing so you intentionally mislead.

gisterme - 03:15pm Feb 11, 2002 EST (#11483 of 11486)

Nice poem, lchic. You're talented! Still didn't answer the question though. :-)

gisterme - 03:31pm Feb 11, 2002 EST (#11484 of 11486)

rshow55 2/11/02 6:59am

"This [MD] is no "rational investment for America..."

So you think a one-time expendature of a few hundred billion dollars to save couple of hundred thousand lives and prevent perhaps a trillion dollars damage for each WMD-armed missile destroyed is not a rational investment, Robert?

I notice you didn't bother to answer the earlier post about that after you claimed that MD expenditures offer no prospect of a reasonable return on investment and that defense planners should be looking at that to make their decisions...

gisterme 2/10/02 1:26am

gisterme - 03:43pm Feb 11, 2002 EST (#11485 of 11486)

rshow55 2/11/02 11:06am

"...I trust we're agreed on what adaptive optics is?..."

http://cfao.ucolick.org/ao/index.shtml

The reference is a good example of what adapive optics can do for the astronomical application, Robert. We're agreed on that. The one small detail you "forgot" to mention from the same reference website is the other bit about reference objects:

"Because the isoplanatic patch for the atmosphere is so small, only a tiny fraction of the sky will be near suitably bright stars that can serve as reference beacons. The most promising way to overcome this limitation is the use of powerful lasers to excite sodium atoms high in the atmosphere, producing an artificial star that can be placed near any target of interest."

Ahem. An honest oversight no doubt. But if there's a nice solid object that can be illuminted by a reference laser, like an ICBM body, a better reference object would be hard to imagine.

What say you, Robert?

rshow55 - 04:40pm Feb 11, 2002 EST (#11486 of 11486)

I say I'm working at my pace. You've sometimes taken weeks to get back to me.

You're interested in right answers, gisterme . . but exactly when you order them up? And at exactly your pace?

We're not playing badmitton.

Still, you make a good point about facts - - a point on which we agree.

If I'm right, on the checkable fact - - does it make any difference? Or would you just change the subject?

Perhaps I'm being unfair - have I been mistaking bad faith for misunderstanding? If so, I'm sorry.

The question of "how do we get closure on issues that are not subjective" has been raised, and I'm working on it.

- - -

I haven't gone off to the library to get the references that show that " 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..." though I feel subjectively sure that I'm correct, because of things I've heard, and my understanding of the physics. (Of course, subjectivity, mine or anyone else's, can be wrong.) But my subjective feeling is connected to a nonsubjective fact - the form of the sine and cosine series - - I made a mistake when I wrote down those series in 11439, though it doesn't change the logic of what I said.

The sine series and cos series are both simple -- a hand held calculator calculates them well and easily - to the number of significant figures the display has. For an angle x , in radians, the series are

sin(x) = x - (x^3)/3! +(x^5)/5! - (x^7)/7! + (x^9)/9! . . .

sin(x) = x - (x^3)/6 +(x^5)/120 - (x^7)/5040 + (x^9)/362880 . . .

cos(x)= 1 - (x^2)/2! + (x^4)/4! - (x^6)/6! + (x^8)/8! . . .

cos(x)= 1 - (x^2)/2 + (x^4)/24 - (x^6)/720 + (x^8)/40320 . . .

(where ". . ." means "and so on, with additional terms in the same pattern". For small values of x, the first few terms are very good approximations for the sine and cosine series.)

suppose x is 10e-5 radians - a serious error for the ABL.

sin(10e-5)=.00001000000...
cos(10e-5)=.99999999995...

That sine represents a serious error, for an aimable laser -- a divergence that great would vitiate any ability of ABL to significantly heat up, much less hurt, a missile at tactical range, even without reflective countermeasures.

The cosine would be hard to tell by measurement form exactly 1 -- it differs from 1 by only .05 parts per billion. Do laser mirrors have to be so parallel as that? I don't think so -- but I'll check.

Again, the question of "how do we get closure on issues that are not subjective" has been raised, and I'm working on it.

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