New York Times on the Web Forums Science

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?

rshow55 - 05:02pm Jan 15, 2002 EST (#10788 of 10798)

In MD10765 gisterme 1/14/02 7:53pm , gisterme asked for examples of analytical problems, involving high dollars, and MD especially, that deserve the phrase "very disappointing."

Guidance is a central issue. MD6397 rshowalter 7/2/01 7:00am includes this:

" I don't think I'm doing US security any harm, or telling anyone anything very surprising, when I say that in the late 1950's and early 1960's, work at Fort Deitrich on biological warfare also included much work on "animal intelligence" -- especially as it related to guidance. How was it that birds or bats had so much greater ability to intercept moving tartgets than the best missiles? The idea crystalized - and it was an entirely reasonable idea, that there must be a gross mistake in the mathematics being used in our guidance systems -- the disparity between the clumsiness of manmade missiles, and the relatively fantastic grace and accuracy made this idea seem compelling. There were somewhat similar huge disparities involved in language processing and cryptography, as well. We had fast, powerful actuators, and plenty of speed and accelleration on our missiles -- but control was very problematic - and the instabilities encountered when tight control was attempted (a problem that was still central last year in MD experiments) were stunning and embarrassing, beside what animals such as bats could routinely do. It became clear that, if animal level control facility, or anything close to it, were achieved in our air to air missiles (or the Russian missiles) combat balances would shift radically. Then, as now, air to air missiles often missed. With good controls, they wouldn't."

MD1941 rshowalter 4/3/01 11:47am cites a key reference, Graham and McRruer, on problems that still remain central in guidance today, including those of MD. These problems are essentially connected to derivation of differential equations from physical models, and some issues involving the use of those de's.

AI is an example -- more connected to MD than gisterme seemed to appreciate, because the most key difficulties built into PDP are also built into our MD guidance problems (including short range missile problems that recently defeated Navy contractors on an expanded Aegis.

MD6131 rshowalter 6/27/01 9:45am ... MD 6133 rshowalter 6/27/01 11:19am
MD6134 rshowalter 6/27/01 11:20am ... MD6136 rshowalter 6/27/01 11:38am

rshow55 - 05:03pm Jan 15, 2002 EST (#10789 of 10798)

In MD6149 gisterme 6/27/01 2:06pm gisterme asks a key question, and sets out a misconception:

"Why would any very complex level of AI be needed to track a ballistic missile? As dirac says, the "B" in ICBM stands for "sitting duck". ICBM payloads follow a nice parabolic trajectory once the boost stage is over. Given the equation of the parabola and the location of the warhead at a particular point in time one could predict where the warhead would be 5 minutes hence by using a hand-held calculator."

The problems in shooting down planes or missiles "air to air" are much the same. For controlling a moving rocket (in a moving frame of reference) with respect to a target (not conveniently set out in a parabola defined with respect to a convenient origin - - stuff often misses. Especially in the real MD case, where accuracy of knowledge is limited enough that homing on the basis of feedback is needed to actually hit the target.

In MD8565 rshowalter 9/6/01 6:24pm I ask a question, and make a comment, that might interest specialists.

Specialists might also be interested in the material (including the material just at the end) in http://www.wisc.edu/rshowalt , which I wrote with S.J. Kline - - in the appendices of http://xxx.lanl.gov/html/math-ph/9807015 and in http://www.wisc.edu/rshowalt/kirch1 - - which illustrates a error in finite integration that occurs, and can be dangerous, in many control systems.

lchic - 06:24pm Jan 15, 2002 EST (#10790 of 10798)

Generalists : bolded words - might these apply to MD admin&strategy?
..THE SYMPTOM, NOT THE DISEASE
/ Marshall Auerback

Attacking the company and its greedy executives may be easy, but it is a sideshow. It's demise is largely due to the complicity of Washington’s leading political, monetary and financial authorities in subverting proper regulation of our liberal market democracy in a wide range of areas: a persistent refusal to regulate properly the derivatives market, a reluctance to fund the Securities and Exchange Commission adequately so as to increase investor protections against and executive accountability for securities’ fraud, and political cowardice in refusing to tackle the accounting profession’s blatant conflicts of interests which, in recent years, have prevented genuinely independent audits. Enron raises broader questions about the wisdom of industry self-regulation, the current integrity of public company financial reporting, and the overall competence (and judgement) of Washington’s leading policy makers. see

rshow55 - 07:18pm Jan 15, 2002 EST (#10791 of 10798)

see ! ! ! ! .

lchic - 07:46pm Jan 15, 2002 EST (#10792 of 10798)

See_Saw

(6 following messages)

New York Times on the Web Forums Science Missile Defense