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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 - 05:34pm Jul 2, 2001 EST (#6420 of 6423)
Robert Showalter showalte@macc.wisc.edu

MD6407 gisterme 7/2/01 3:25pm

"using a line-of-sight speed-of-light weapon like a powerful laser one doesn't need to know the exact range to the target."

That's right.

But you need angular controls to be exact, at every stage, or you need to be able to tolerate the angular spread that builds up.

For the proposed systems I'm aware of, at the level I understand them, assuming basic technical performance similar to open-literature performance, that build up is far too much for practical operation of the weapon.

And you can get a false sense of system resolution by looking at "lasar signitures" -- which are neat, but which only measure exactly what they happen to measure.

lunarchick - 05:43pm Jul 2, 2001 EST (#6421 of 6423)
lunarchick@www.com

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rshowalter - 05:44pm Jul 2, 2001 EST (#6422 of 6423)
Robert Showalter showalte@macc.wisc.edu

I meant "radar signitures" - not "lasar signitures" -- though there may be analogous effects with light, too.

Back in ancient days, when the speed of light was the same, and radar wavelengths also the same for many systems, people knew that a differently shaped object would have a different echo pulse -- and though you might not know where the object came from, within a milliradian -- you might know details of geometry of the object itself that would, for the range, correspond to nanoradians or less.

That tells you that radar can have wonderful geometrical and angular resolution in a sense - for a "frame of reference about a particular target" but not even remotely that resolution for telling you where the target is.

To hit the target, however it is shaped, you have to know where the target is.

Though you can be interested in how it is shaped, too -- and some fancy decoy discrimination CAN be done for stupidly designed decoy - payload systems.

And maybe all our potential enemies are stupid.

I recall an old ad, circa maybe 1890, that advertised a Whiskey made by "honest North Carolina people -- who wouldn't dilute their whiskey, even if they knew how."

My people, who are from North Carolina, always smiled at that old ad.

If you're worrying about the odds of missile defense, assumptions like the one in that ad aren't so funny.

rshowalter - 05:46pm Jul 2, 2001 EST (#6423 of 6423)
Robert Showalter showalte@macc.wisc.edu

I think the Bush administration is honestly, but incorrectly, putting too much trust in the "magic" of lasar weaponry. And I believe that they are mistaken about how magical these systems can be.

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