20-05-2010, 21:30
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מומחה לתעופה, תעופה צבאית, חלל ולווינות. חוקר בכיר במכון פישר
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חבר מתאריך: 02.07.05
הודעות: 11,691
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ותגובה נוספת, חריפה יותר
Theodore Postol and George Lewis are said to rely on Looney Tune physics as they the debate over Standard Missile-3 testing record provoked by the New York Times article continues. The charge comes from Missile Defense Agency that stated physicists are incapable of assessment because the final telemetry information is classified.
Last week, missile-defense critics Theodore Postol and George Lewis touched off a controversy after they questioned the Pentagon’s claims of test success for the Standard Missile-3 (SM-3) interceptor. But in a roundtable yesterday with bloggers, Missile Defense Agency spokesman Rick Lehner suggested, in effect, that the two critics were relying on Looney Tunes physics to go after the program.
MDA claims the SM-3 has a strong track record, hitting 84 percent of incoming targets in 16 different test events between 2002 and 2009. But the question Postol and Lewis raised was simple: Does hitting a target missile’s airframe, as opposed to its warhead, count as a hit? “In eight or nine of the 10 SM-3 intercept tests from 2002 to 2009 … the SM-3 kill vehicle failed to hit the warhead target directly,” they wrote. “This means that, in real combat, the warhead would have not been destroyed but would have continued toward the target and detonated in eight or nine of the 10 SM-3 experimental tests.”
In other words, the SM-3’s kill vehicle would punch right through the thin walls of the rocket body like a bullet zipping through an empty soda can, they argued.
So, is the SM-3’s success rate much lower than the Pentagon claims? Not so, said Lehner. “Contrary to what Doctors Postol and Lewis said, after being hit, the — well, the interceptor does not pass through the body of the — of the target missile,” he said. “That’s akin to, you know, Wile E. Coyote running through a glass or plate glass and leaving the exact outline of his body after he goes through.”
The SM-3’s kill vehicle “hits it so hard and so fast that the energy that comes from that collision is just simply too great and causes a catastrophic failure of the missile,” he added.
Still, it does matter where an interceptor hits. SM-3 is a “hit-to-kill” system: It relies on kinetic energy generated by collision to destroy its target, not an explosive charge. And as Lehner acknowledged, hitting the warhead does matter when you are up against a “separating target” (a medium-range, multistage ballistic missile like Iran’s Shahab-3) versus a “unitary target” like the short-range, single-stage Scud missile.
In tests against separating targets, Lehner said the SM-3 had a record of hitting five out of six. “That wasn’t mentioned in the story [The New York Times write-up of Postol and Lewis' claims] either, although the Times did have that information,” he said.
Either way, this isn’t likely to settle things. Lewis and Postol were trying to make a larger point about who, in the end, weighs the Pentagon’s claims when it comes to the performance of missile-defense systems. The test record, they argued, “is yet another example of why measures need to be taken to provide a truly independent source for the White House and Congress to confirm the veracity of claims being made by the MDA and others in the Defense Department.
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