Anti-Ballistic Missile Fails

[ELVIS]

I am basically familiar with the previous tests...

Obviously there are people who are interested in making this system work...

I'm personally optimistic about it...

[Nickdfresh]

Good luck. If we are ever attacked by an alien race of large, hostile barn doors, the missiles might be able to hit them. But there are too many limitations to "hitting a bullet with a bullet."

[lucky wilbury]

actually the patriot has a good track record over the past few years sinces it was redesigned

[DEMON CUNT]

Programs like these cost taxpayers, like you and I, billions.

This is about greed and 'no bid contracts.' It's not about keeping us safe. The boards of directors of the corporations with the government contracts don't give a FUCK about any of us common folk.

We are being cheated out of billions and billions of dollars. That money could fix up our schools or help you pay for daycare. But it goes to the likes of Ross Perot, etc.

[Big Train]

So Nick, answer my fuckin question...what do you think WILL work?

[ELVIS]

Complaining...

[Nickdfresh]

Originally posted by lucky wilbury
actually the patriot has a good track record over the past few years sinces it was redesigned

Like shooting down those dastardly British Tornado Jets. It has a serious problem with its "friend or foe" ID system. Maybe they redesigned it again, because everytime they find a new flaw with it.

[Nickdfresh]

Originally posted by Big Train
So Nick, answer my fuckin question...what do you think WILL work?

I think R & D into laser systems and even a missile defense system is fine. But pumping billions into this stuff is silly.

Trying to shield America from all threats is the height of absurdity and will give us the (WWII French) "Maginot Line" mentality that we are invincible. For instance, would this thing, even if it worked, have stopped 9/11? The answer is no.

Also there's a wider issue here, we invade Iraq as you keep insisting that Saddam was such a threat with his phantom WMD's. Was this system being designed with Iraq in mind. No. It is being designed with the NORTH KOREANS and IRANIANS in mind because of the NK missile proliferation. Yet we really do nothing about these emerging threats.

Also if this system is deployed, we will enter into a new arms race with China, a country with relatively few ICBMs, but one that will quickly move to develope countermeasures and to expand their nuclear weapons.

And again, it is against the 1972 ABM Treaty, so I guess we have no more right to judge other nations for violating or throwing out any treaties that they no longer feel like abiding by.

[Big Train]

Originally posted by Nickdfresh



Trying to shield America from all threats is the height of absurdity and will give us the (WWII French) "Maginot Line" mentality that we are invincible. For instance, would this thing, even if it worked, have stopped 9/11? The answer is no.

Also there's a wider issue here, we invade Iraq as you keep insisting that Saddam was such a threat with his phantom WMD's.

Was this system being designed with Iraq in mind. No. It is being designed with the NORTH KOREANS and IRANIANS in mind because of the NK missile proliferation. Yet we really do nothing about these emerging threats.

Also if this system is deployed, we will enter into a new arms race with China, a country with relatively few ICBMs, but one that will quickly move to develope countermeasures and to expand their nuclear weapons.

And again, it is against the 1972 ABM Treaty, so I guess we have no more right to judge other nations for violating or throwing out any treaties that they no longer feel like abiding by.

It takes billions.

It is designed to protect us against other threats (whether it works or not). We will never be invincible, nor do I think anyone is under the impression that we are. Attempting to shield from as much harm as possible is their duty. Not trying would be failing in that duty.

You've obviously never heard what I have to say on Iraq and just attribute to me a general line of reasoning that I "keep insisting on", which is another example of how you hear what you want.

BY your own admission, we can't run over every country that has them (and I agree). Nobody is going to disarm, especially now that India and Pakistan seek them out as well. The point is to have as many deterrents as possible to get people to avoid using them and missle defense is just as important as diplomacy and sanctions in that respect.

With respect to China, that's just speculation. What's to say they won't just develop a missle defense system of their own?

The Treaty needs to be amended. It is a non-nuclear defense system, not an arms system or nuclear based attack system. Other countries should have it to. It's about having a viable option in a nuclear crisis that doesn't involve Mutually Assured Destruction and it's an option I would like to have.

[BigBadBrian]

With Nick's line of thinking, the Air Force would still be flying P-51's.

[Nickdfresh]

Originally posted by BigBadBrian
With Nick's line of thinking, the Air Force would still be flying P-51's.

Well, the P-51's did actually work and could shoot down their targets unlike this missile.

[Nickdfresh]

THE BUSH RECORD: Missile Defense
Interceptor System Set, But Doubts Remain
Network Hasn't Undergone Realistic Testing

By Bradley Graham
Washington Post Staff Writer
Wednesday, September 29, 2004; Page A01

At a newly constructed launch site on a tree-shorn plain in central Alaska, a large crane crawls from silo to silo, gently lowering missiles into their holes. The sleek white rockets, each about five stories tall, are designed to soar into space and intercept warheads headed toward the United States.

With five installed so far and one more due by mid-October, Defense Secretary Donald H. Rumsfeld is preparing to activate the site sometime this autumn. President Bush already has begun to claim fulfillment of a 2000 presidential campaign pledge -- and longtime Republican Party goal -- to build a nationwide missile defense.


But what the administration had hoped would be a triumphant achievement is clouded by doubts, even within the Pentagon, about whether a system that is on its way to costing more than $100 billion will work. Several key components have fallen years behind schedule and will not be available until later. Flight tests, plagued by delays, have yet to advance beyond elementary, highly scripted events.

The paucity of realistic test data has caused the Pentagon's chief weapons evaluator to conclude that he cannot offer a confident judgment about the system's viability. He estimated its likely effectiveness to be as low as 20 percent.



"A system is being deployed that doesn't have any credible capability," said retired Gen. Eugene Habiger, who headed the U.S. Strategic Command in the mid-1990s. "I cannot recall any military system being deployed in such a manner."

Senior officials at the Pentagon and the White House insist the system will provide protection, although they use terms such as "rudimentary" and "limited" to describe its initial capabilities. Some missile defense, they say, is better than none, and what is deployed this year will be improved over time.

"Did we have perfection with our first airplane, our first rifle, our first ship?" Rumsfeld said in an interview last month. "I mean, they'd still be testing at Kitty Hawk, for God's sake, if you wanted perfection."

This notion of building first and improving later lies at the heart of the administration's approach, which defense officials have dubbed "evolutionary acquisition" or "spiral development." Bush has scaled back President Ronald Reagan's vision of a vast anti-missile network and pursued a less ambitious system. At the outset, the system will be aimed only at countering a small number of missiles that would be fired by North Korea, which is 6,000 miles from the West Coast of the United States.

But Bush also has funded an expanded array of missile defense projects, including land- and sea-launched interceptors, an airborne laser, and space-based weapons. So far, he has spent $31 billion on missile defense research and development, and his plans call for an additional $9 billion to $10 billion a year for the next five years. Beyond that, the administration has provided no final price tag. In 2005, the cost of missile defense will consume nearly 14 percent of the Pentagon's entire research-and-development budget.

While more money has gone into missile defense under Bush than into any other military R&D project, the Pentagon has exempted the missile defense program from the traditional oversight rules meant to ensure that new weapons serve the needs of military commanders.

Administration officials say the procedural shortcuts and the increased spending have yielded record gains in record time. The urgency, they say, is justified by a growing U.S. vulnerability to attack from hostile states pursuing long-range missiles -- most notably North Korea and Iran.

Critics warn that such haste has made waste -- and is unnecessary. The urgency, they suspect, has been more a reflection of politics than concerns about the missile programs of North Korea and Iran, which still face significant technical hurdles. The deployment is being timed, they contend, to help Bush's reelection campaign.

They also caution that fielding a U.S. anti-missile system before it has undergone realistic testing risks inducing a false sense of security and locking the United States into flawed technology.

"The design gets frozen in order to build something, so development is stopped," said Philip E. Coyle III, the Pentagon's chief weapons evaluator during the Clinton administration. "You can't be building a house and changing the floor plan at the same time."

Out With the Old

Normally, when a weapons system is conceived, the Pentagon sets specific requirements that must be approved by a committee of senior military officers. The project is then assessed periodically by the Defense Acquisition Board, a group of high-ranking defense officials from various offices.

This accountability apparatus has been shunted aside in the case of missile defense. No requirements document was drawn up, and the traditional reviews and assessments have been bypassed. Instead, the Missile Defense Agency (MDA), which is responsible for developing the system, has been allowed to devise its own goals, test schedules and program reviews.

When Rumsfeld authorized this extraordinary autonomy in January 2002, he said that technological challenges and urgent national security concerns justified it. As a former executive in the pharmaceutical industry, Rumsfeld by his own account was influenced by the vigorous trial-and-error competition that often precedes the creation of new drugs.

Other historical models also inspired Pentagon authorities. One was the National Reconnaissance Office, established in great secrecy in the 1960s to develop and operate spy satellites. The other was Israel's decision, in 2000, to declare its Arrow anti-missile system operational after just one successful intercept test.

"Since we have urgent needs, we sometimes cut corners in developing systems, meaning we field them before we've developed everything," said Arieh Herzog, director of the Israeli Missile Defense Organization. He said he held "many talks" about Israel's approach with Lt. Gen. Ronald T. Kadish, MDA director at the time.

Opponents in Congress and elsewhere say this approach has been taken too far in the case of the U.S. system. They warn that the lack of established baselines for the missile defense program has made it difficult to hold the Pentagon accountable for performance and cost.

"We're in this hugely expensive race to build something, but we don't know how much it'll cost in the end or what it'll do," said Sen. Jack Reed (D-R.I.), a member of the Armed Services Committee.

An audit by the Government Accountability Office, released in April, cited an absence of reliable, complete baseline estimates of system performance and cost. Without this information, the GAO said, policymakers in the Pentagon and Congress "do not have a full understanding" of the system's overall cost and actual capabilities. The audit concluded that the system being fielded this year remains "largely unproven."

Supporting Cast

Pentagon officials say the program remains subject to extensive internal supervision, even with the departure from traditional procedures. Michael W. Wynne, the Pentagon's acting head of acquisitions, told a Senate committee in March that he meets weekly with the MDA's director. In contrast with other programs he oversees from a distance, Wynne described his contacts with top MDA officials -- and with Rumsfeld -- as "more direct and generally carried out in face-to-face discussions."

Wynne said other senior Pentagon officials also have had a say in shaping and scrutinizing the program. He pointed to the Missile Defense Support Group, which consists of mid-level representatives from Rumseld's office, the Joint Staff and each of the military services. The group has met 47 times since its creation in March 2002.

"No program in the department receives more scrutiny -- either in level or frequency -- than the Missile Defense Program," Wynne testified to the Senate Armed Services Committee.

But interviews with support group members revealed they have played only an advisory role. Several said the group often learned of some important decisions after the fact.

"We're not a critical-decision review group," said Glenn F. Lamartin, a senior Pentagon acquisition official who chairs the group. "We're a support group. We provide advice. Our engagement is different than if we were operating under the old system of review and oversight."

Lately, some senior military commanders have signaled an interest in shifting back toward some sort of formal requirement process. The Strategic Command, which will oversee operation of the missile defense system, has proposed a "warfighter involvement program" to give commanders a greater voice in the system's development.

Another important source of internal review is supposed to be Thomas P. Christie, the Pentagon's chief weapons evaluator. But he is in an awkward position.

By law, his Operational Test and Evaluation office is mandated by Congress to judge the readiness of major weapons systems before they are deployed, which it does by comparing the results of "operational" tests with the requirements for the system. In the case of missile defense, however, no formal requirements exist, and the test data so far come from early "developmental" flights, not more realistic operational ones.

Christie's estimate that the system may be only 20 percent effective contrasts with a prediction from the MDA of more than 80 percent effectiveness. The difference reflects disagreement over which test data to include in computing the estimates.

Christie wants to count all flight results, including earlier test failures. The MDA argues that causes of those failures have been fixed, so the data can be discarded. Its estimates are based largely on computer simulations and testing of individual components.

The MDA's director, Air Force Lt. Gen. Henry A. "Trey" Obering III, said in an interview earlier this month that both sides were trying to settle on a common set of data. Two other senior defense officials said this week that an agreement had been reached on "selection criteria" for the data and that the gap between the disparate estimates had begun to narrow.

The numbers, which are classified, carry considerable importance because a future U.S. president would rely on them in a crisis.

"He will want to know what his options are and will turn to his commanders and ask how sure they are that the system will work," said a senior Pentagon official involved in the assessment.

Delays Persist

After Bush took office, Pentagon officials outlined a plan of stepped-up flight intercept tests. The plan held, more or less, through the end of 2002 and several successful intercepts. But unexpected difficulty in producing a new booster rocket has stalled intercept tests since December 2002.

The booster's job is to carry a "kill vehicle," a 120-pound package of sensors, computers and thrusters. Once in space, the kill vehicle separates from the booster and closes in on an enemy warhead, destroying it in a high-speed collision.

Earlier flight tests used a surrogate booster that flew at only half the speed of the booster that is being produced for the system. MDA officials said they have not wanted to try more intercepts until that new booster can be incorporated into the tests.

By spring of this year, the new booster was ready, but the discovery of a faulty circuit board in the kill vehicle prompted Pentagon officials to order a lengthy bottom-up review of all components. In mid-August, the missile interceptor was again set to go when technicians found a glitch in the booster's flight computer. Replacing the computer created another delay.

Earlier this month, Obering, the MDA's director, announced a further postponement after discovering modifications that had been made to the interceptor without thorough ground testing.

This leaves the administration proceeding with deployment after only eight intercept tests -- the most recent conducted 21 months ago. Five tests resulted in hits, but all used the same limited test range in the Pacific and employed surrogates for tracking radars as well as for the booster.

A key X-band radar -- a towering structure being built to float at sea on two motorized pontoons the size of Trident submarines -- will not be ready for another year at least. Also still in development is a satellite network to replace a three-decade-old constellation of early-warning satellites. Both the X-band and the new satellites are critical in assisting the kill vehicle to distinguish the warhead from decoys and debris.

Physicists and defense experts, including some affiliated with the Union of Concerned Scientists, continue to dispute the MDA's claims that the system will be able to identify a warhead in a field of decoys -- a process known as "discrimination." Tests so far, using only relatively simple targets, have done little to resolve the issue.

Pentagon officials say the system has been subjected to an extensive array of ground tests and computer simulations. The failures on intercept attempts, they note, resulted from problems with the quality of individual parts, not from basic design flaws.

"If you really look at where we've encountered problems, they have not been things that required technological breakthrough. They have been in attention to detail and quality," said Maj. Gen. John Holly, the MDA's manager for what is formally known as the Ground-based Midcourse Defense system.

But both Christie and the Defense Science Board, a Pentagon advisory board, have cited limits to the computer models. And the persistent quality control problems have led a number of scientists, defense specialists and Democratic lawmakers to argue that the system's sheer complexity makes it highly vulnerable to the malfunction of a single part.

'We Needed a Date'

The Pentagon has aimed at having the Alaska site ready by Sept. 30. Kadish, the former MDA director, said that date was chosen by his agency in early 2002 for "internal management purposes," not by political appointees with an eye toward the Nov. 2 presidential election.

"We needed a date for people to work to," he told the strategic forces subcommittee of the House Armed Services Committee in March.

At the time the date was picked, the Alaska site was being conceived primarily as a "test bed" that would allow for more realistic flight testing and cold-weather ground operations. It could be used in an emergency to thwart a real attack, defense officials figured, but that would not be its main purpose.

In the summer of 2002, the plan began to change. Pentagon officials proposed turning the site into a fully operational anti-missile facility and deploying more interceptors there while still using it as a test area. Bush approved the plan a few months later, ordering deployment in 2004.

Despite the slippage in the test program, the administration has held fast to that deadline. In recent weeks, Bush and Rumsfeld have reiterated their intention to activate the system by year's end.

This will not be the first time Pentagon officials have pushed a new weapon system into service while it is still in its experimental phase. The Joint Surveillance Target Attack Radar System (JSTARS), a ground surveillance aircraft, was rushed into action in the 1991 Persian Gulf War, and Predator and other unmanned reconnaissance aircraft were hurriedly deployed in the Balkans and Afghanistan.

But JSTARS and the drone aircraft were far simpler to develop than missile defense. Coyle, the former Pentagon weapons evaluator, compared the idea of deploying while testing the missile defense system to building a picket fence, one picket at a time, over several years. Until the whole thing is complete, such a fence is not much use, he said.

Coyle and others also worry that placing the system on alert will distract from further testing and development. They point to the experience in the 1990s of a shorter-range anti-missile system known as Theater High-Altitude Area Defense, or THAAD. The Army required the developer of that system to produce 40 prototype missiles, reliable and rugged enough to use in a combat emergency. The pressure to deploy something early led to compromises in design and testing, which hampered the program and contributed to years of delay.

Pentagon officials are still wrestling with what balance to strike between keeping the system functioning and suspending operations to run tests.

"You could say that if you put it on alert, it might be a distraction to the development and evolution of the system," Rumsfeld said. "But you could say just the opposite -- that by putting it on alert, you force up a whole series of issues that you need to think through, work through."

Rumsfeld has made it clear that in the absence of an international crisis involving a heightened threat of missile attack, he would favor giving priority to continued testing. Nevertheless, the administration does not intend to wait for more proof of performance before expanding the system.

In addition to 16 interceptors already ordered for the Alaska site at Fort Greely -- plus four for an alternate California site at Vandenberg Air Force Base -- the 2005 budget provides money for 10 more interceptors in Alaska. Talks also are underway with several countries about establishing an interceptor site in Europe.

'The Sky Did Not Fall'

In the early months of the Bush administration, congressional Democrats plotted to block White House plans to expand work on missile defense. After the World Trade Center and the Pentagon were struck on Sept. 11, 2001, they tried to argue that the attacks showed that the United States had more to fear from low-tech terrorism than high-tech missiles.

But the attacks, by giving new emphasis to homeland defense, have played to the advantage of missile defense proponents. Amid a general surge in military spending, Bush has received nearly all of the money he has sought for missile defense.

Democratic lawmakers opposed to Bush's program concede the debate has shifted. It is no longer an ideological battle, centered on arms control concerns, over whether to deploy at all. Now, they say, it is a more practical argument over how much to build and how fast.

"The debate is now about whether or not we continue to press ahead at the full speed we're going, with record amounts of money being spent, despite the fact that there's been no realistic testing," said Sen. Carl M. Levin (Mich.), the ranking Democrat on the Armed Services Committee.

Rumsfeld, addressing an audience of government officials and contractors last month, said the upcoming deployment is "somewhat of a disappointment for those who were convinced it would fail." Noting cordial discussions he had held only days earlier with Russian officials about missile defense, he chided arms-control advocates who had forecast that the U.S. initiative would upset relations with Moscow.

"The sky-is-falling group was wrong," he said. "The sky did not fall. It's still up there."


Permission to Republish
© 2004 The Washington Post Company


The first anti-missile interceptor is lowered into a silo in Alaska. (John Hagen -- Fairbanks Daily News-miner Via Ap)

[knuckleboner]

i'm not a big fan of the concept.

it's not the money or the technological hurdles. i'm fine with the apollo decision. and, i'm behind bush if he wants to go to mars.

but, i just don't see the point in a limited anti-missile system. this is not reagan's star wars. it's not intended to stop a massive number of inbounds.

just the 1 rogue missile. well, i'm not sure that's actually a viable threat. terrorists will never have the capacity to actually launch an ICBM. and i highly doubt an actual nation would be foolish enough to take just 1 pot shot against us.

if the system were the theater-based AEGIS system to protect American troops in certain hotspots, great, i'm behind that.

but i think the threat of an ICBM launched at us is far too small to justify the cost.

[Nickdfresh]

December 25, 2004


THE NATION
Little Room for Error in Catching a Missile


By Charles Piller, Times Staff Writer


The first line of defense in America's next antimissile system fails or succeeds in a window of 90 seconds.

That's all the time there is, designers estimate, for a satellite to detect the flash of an enemy launch, determine that it is real and send off a counter-missile from the ground.

It all happens too fast to include a human in the loop.

"Time is of the essence," said Craig van Schilfgaarde, the Northrop Grumman Corp. engineer in charge of the project.

Known as "boost-phase" interception, it is designed to be the first "layer" of defense, firing rockets at enemy missiles just after launch, when they are most vulnerable.

The military has already deployed parts of the two other layers in the missile defense system — one targeting missiles as they cruise through space in midflight and the other aimed at descending warheads when they are just above their targets.

The three layers are the cornerstone of President Bush's plan to defend the country against rogue nations, such as North Korea and Iran, that are gradually developing the ability to produce weapons with global reach.

But the system has already faced serious problems.

The midcourse missile failed a test Dec. 15 when it shut down before leaving its silo at the Ronald Reagan Test Site at Kwajalein Atoll in the central Pacific Ocean. It was the second failure in a major test in two years.

On Dec. 17, the Pentagon announced it was dropping plans to activate the existing pieces of the missile defense system this year because it had not completed full "shakedown" testing.

The boost phase reaches into an even more complex realm of design, in part because of the speed with which it must identify and destroy an enemy missile.

The payoff could be big. Terry Little, executive director of the government's Missile Defense Agency, said the boost-phase interceptors could destroy 80% to 90% of enemy ICBMs, leaving the other layers to take care of the rest.

But a recent Congressional Budget Office technical report suggested that the boost-phase system, scheduled for deployment in 2011, would press the far edge of what was physically possible in an antimissile system.

Philip Coyle, who headed the Pentagon's testing office during the Clinton administration, said the design of the boost-phase system was already buckling under its own complexity.

"The [congressional] analysis confirmed that boost-phase missile defense isn't practicable," Coyle said. "You can't fool mother nature."



Today's missile defense programs were inspired by President Reagan's promise to end "nuclear blackmail" with his Strategic Defense Initiative, a plan to shield the nation against an all-out nuclear attack using satellite-fired interceptors.

Dubbed "Star Wars" by opponents in Congress, Reagan's program fell victim to technical dead-ends, cost overruns and concerns that it would violate the 1972 Anti-Ballistic Missile Treaty, which banned nationwide missile defense systems.

Missile defense languished until 2002, when Bush withdrew from the treaty, which he considered a Cold War-era anachronism.

Instead of trying to defend against all-out nuclear attack by a major power, today's plan targets the less-advanced arsenals of emerging nuclear states.

The entire system is budgeted at about $50 billion over the next five years and is likely to cost several times that amount to build, deploy and maintain.

In July, the Missile Defense Agency began deploying the midcourse interceptors in Alaska. A second battery is scheduled for deployment next year at Vandenberg Air Force Base in Santa Barbara County.

Mobile Patriot antimissile systems, a key part of the descent layer (also known as the terminal layer), have been deployed.

A year ago, Northrop won a $4.5-billion contract to develop the boost-phase interceptors. Congress has approved $348 million for the current fiscal year.

Boost defense "would never be able to handle every situation that anybody could conceive of," said Little of the Missile Defense Agency. "But we could handle enough that we could look at ourselves as an 80% or 90% solution."

The allure of striking enemy missiles in the boost phase is that they are easily identified by their plumes just after launch and, because they are ascending, cannot use their full bag of tricks to dodge and deceive.

So far, the only part of the boost-phase system that has been built is a single camouflaged launcher with dual launch tubes. The 30-foot-long trailer is parked beside a pile of scrap metal outside a Northrop warehouse near Baltimore.

Little said that the system would not need the technical leaps that Star Wars required.

"The technology is in hand," he said. "It does not hinge on any kind of a technology breakthrough."

The trick is getting the pieces to work together — all in the space of a few minutes at most.

To destroy a missile in the boost-phase requires an unprecedented coordination of space-based sensors, signal-analysis computers, interceptor agility and enough sheer thrust to lift a 10-ton object to about 20 times the speed of sound in less than a minute.

Each interceptor consists of a two-stage booster, followed by a liquid-fuel rocket that steers the kill vehicle on the last leg of its journey to the target. It would travel at about 13,400 mph.

After infrared sensors on satellites detect the enemy launch, interceptors would be directed to the target by terrestrial command stations that constantly update the target's flight path. Onboard sensors would take over at close range.

The interceptor's goal is to strike the enemy missile before the warhead separates from its rocket, usually at an altitude below 300 miles.

The interceptors gain speed and agility because they don't have to haul a heavy explosive warhead. Instead, they are designed to destroy their target with the force of collision.

This "kinetic" attack — described as hitting a bullet with a bullet — demands uncanny accuracy.

"What is the precision required? I would characterize it as within less than a meter" over hundreds of miles traveled, he said.

To catch an ICBM streaking across the sky, interceptors would be placed about 600 miles back from the target's launch site on land or sea.

The military also is developing an airborne laser to shoot down ICBMs as they ascend.

"These guys are very, very immature in their development," said Northrop's Van Schilfgaarde, referring to the missile programs of North Korea and Iran. Even if their technology improves, he said, "we have tremendous flexibility."


--------------------------------------------------------------------------------


Even before it has gotten off the drawing boards, the boost-phase system has drawn criticism from a variety of scientists and engineers, who see it as technological hubris.

It's a needlessly costly and complicated system for a threat that could, for example, be more easily neutralized with preemptive strikes, said Theodore A. Postol, a missile expert at MIT.

The agency's boost-phase plan faces a conundrum that has plagued missile defense since World War II: Technology advances tend to favor offense over defense.

The Missile Defense Agency said that 27 nations, including several with unstable governments, have ballistic missiles. No rogue nation can deliver a nuclear or chemical warhead to the United States, but each is striving to improve its technology. And proliferation is accelerating.

The technical challenges of boost-phase defense are best captured in the problem of Yazd, an ancient city of about 500,000 in the geographic center of Iran.

To down a missile launched from Yazd and other potential Iranian launch sites, up to seven interceptor batteries would be needed in such areas as Iraq, Turkmenistan and the Gulf of Oman — areas that might be hard to reach or secure.

"If you can't get in close, you don't have a boost-phase capability," Van Schilfgaarde acknowledged.

The Congressional Budget Office report said that defending against missiles from large countries might require interceptors that travel up to 22,000 mph — beyond today's technology.

One of the most complex parts of the boost-phase interception is its sensing and targeting system. Launch commands would have to be automated because the launch window would close long before a human being could evaluate sensor data, particularly if several ICBMs were fired at once.

Yet spy satellites that would direct the action are far from foolproof.

"Sensors are subject to huge [signal] noise problems, so you have to be careful not to launch too soon," said David Mosher, an antimissile expert with the Rand Corp. in Arlington, Va.

"Even bonfires are a problem," said Coyle, the Clinton Pentagon official. "If you make them hot enough with chemicals, to our satellites at first glance they look like a rocket going off."

Bigger doubts involve interceptor accuracy.

Midcourse missiles, which use a similar kinetic attack, have a spotty record. They have hit targets in five of nine tests; succeeding only under what Coyle regards as rigged conditions. During the recent test in Alaska, the rocket failed to leave its silo.

Even against slower-moving short- and medium-range rockets, antimissile systems have been troubled. Patriot interceptors failed to hit nearly all of their targets during the 1991 Persian Gulf War, according to a congressional investigation and an analysis by outside scientists. In the Iraq war, Patriots mistakenly downed two coalition aircraft.

For boost phase, a glancing blow could prove worse than a simple miss. If the interceptor hits the missile body — an error of a couple of feet over hundreds of miles traveled to the target — an Iranian weapon aimed at San Francisco, for example, could end up in Russia.

The Missile Defense Agency regards the risk as unfortunate but acceptable.

"Everything else being equal, a warhead not hitting its intended target is a good thing," Little said. As bad as it would be to destroy another populated area, he added, "what's the alternative? It's worse."

The interceptors could also be mistaken as hostile missiles by nearby nations.

"The interceptor trajectories from North Korea are generally to the northwest," noted a critical 2003 report from the American Physical Society, a leading scientific organization. "An interceptor fired in defense runs the risk of triggering retaliatory action by China or Russia."

Little said critics' concerns and a funding cut by Congress prompted his agency to restructure the development program for the boost-phase missiles.

Now a preliminary system will be produced before full development. If Northrop can't demonstrate that the components work within three more years, the agency may rethink or cancel the contract.

But the alternatives are also problematic.

Some advocates of missile defense in Congress insist that only a space-based system — a new Star Wars — could provide sure global coverage.

But an orbital defense would pose even more formidable technical challenges and cost up to $224 billion, the congressional report said.

To mount a credible orbital system against North Korea and Iran, up to 10,909 interceptors, together weighing more than 1,000 metric tons, would be needed, the congressional report said. That would be more than twice the projected weight of the completed International Space Station, the largest space assembly in history.