U.S. Missile Defense Can be Fooled by Decoys, Documents Say

WASHINGTON — Documents published by the U.S. Missile Defense Agency over the past two years appear to confirm what experts have charged is a fundamental flaw of the national missile defense system the Bush administration plans to make operational in Alaska this year (see GSN, Sept. 22).

The documents — technical appeals for innovative ideas from the small business community — say readings from the sensors that would be used by the Ground-based Midcourse Defense (GMD) system are “not adequate” for distinguishing an enemy warhead from a decoy or other nearby objects.

Furthermore, they suggest that the system, if used, might face numerous decoys and other sophisticated countermeasures. That appears to undercut assertions by officials that missile defense would provide a “modest” or “rudimentary” defense against a “limited” threat.

The problems are described in little-noticed solicitations published on the Internet by the Missile Defense Agency’s Small Business Innovation Research (SBIR) program, written in fairly technical language with the intent of attracting innovative technological solutions to problems. Critics say the language appears to confirm a fundamental flaw that they have argued for years would render the system ineffective at defeating even a basic ICBM attack.

“It’s the Achilles heel of this system,” said Ted Postol, an MIT arms control expert. “Given the fact that they have only certain sensors they can use, [the problem is] impossible to solve.”

“Apparently the big defense contractors — Boeing, Raytheon, Northrop Grumman and Lockheed — have not been able to solve this problem, or else the MDA would not be turning now to small businesses for creative ideas,” said Philip Coyle, the Pentagon’s former top weapons testing official, now a senior adviser with the Center for Defense Information.

The system reportedly faces other serious technological challenges that could hamper effective operation, such as significant delays in the flight test program (see GSN, Aug. 18) and in producing a new rocket booster, and insufficient overall development that has delayed the onset of realistic operational testing.

Even if the system could be made to work, said Senator Jack Reed (D-R.I.) in an e-mail to Global Security Newswire, “It will still have virtually no capability to tell the difference between decoys and real warheads, which means it will be essentially useless against any enemy capable of attacking us with a nuclear missile.” 

Distinguishing a warhead from a decoy is “one of the most difficult technical problems they face, and to the degree it cannot be solved, it will prevent the GMD system from being effective, now and in the future,” Coyle said.

While acknowledging that countermeasures pose a challenge, administration and agency officials have asserted that the system could offer an effective defense against “limited” ICBM threats it would face in the near future.

The Missile Defense Agency “will present to our combatant commanders by the end of 2004 an initial missile defense capability to defeat near-term threats of greatest concern,” then-MDA Director Lt. Gen. Ronald Kadish said in congressional testimony in March.

‘Not Adequate’The Ground-based Midcourse Defense system is being developed to intercept enemy warheads in space as they head toward the United States. On the president’s order, the Pentagon plans to install up to 10 interceptors this year in Alaska and California to offer some defense against a projected North Korean ICBM capability. The Missile Defense Agency has reported that it lowered the fifth interceptor into its silo at the Alaska site this week (see GSN, Sept. 24).

An additional 10 are scheduled for emplacement in 2005 and the administration is requesting money this year for at least 10 more beyond that.

Kill vehicles launched from those sites would be required to “discriminate” —using heat sensing, infrared sensors — an enemy warhead from decoys and other objects in a matter of seconds with the hope of striking the warhead.

A key technical difficulty of that challenge, experts have said, is distinguishing a warhead from decoy balloons, chaff or other objects that might resemble the weapon to the kill vehicle’s sensors. To the infrared sensor, the oncoming warhead appears as a very rough blur among other blurs, according to Coyle.

“Even though the EKV [exoatmospheric kill vehicle] has already had to commit to a target, all it sees is a bunch of shapeless blurry pixels.  If there are two objects like that in the field of view, the EKV has no way of knowing which is which,” he said, citing photos published in a report he co-authored in May.

A key passage from two small business solicitations published in late 2002 appears to confirm that that challenge has not been solved.

“Target discrimination (the ability to identify or engage any one target when multiple targets are present) during National Missile Defense (NMD) midcourse engagement is a complex technological hurdle. … Feature differences among decoys, penetration aids, and targets are not adequate for discrimination by current missile passive IR sensors,” it says.

The agency is pursuing advanced X-band radars that could aid the discrimination system by showing the shapes of the warhead and other objects. However, they will not be deployed at least for another year and along with the infrared sensors could be fooled by an “antisimulation” countermeasure of concealing the warhead in a Mylar balloon amid a field of empty, decoy balloons, critics say.

The small business solicitations suggest the system could face in the near term such countermeasures in the event a threat materialized.

“Threats envisioned for the near- and far-term are a challenging mixture of countermeasures that include chaff, jamming, low observable RVs (re-entry vehicles), balloons, coatings, antisimulation, and simulation, among other countermeasures, that will require novel approaches to the discrimination problem,” according to a document published this summer.

Another solicitation posted this summer says that “Ballistic missile threat capabilities continue to proliferate and progressively evolve to fainter targets and the use of more sophisticated decoys conditions that increase the potential limitations of background clutter on surveillance system performance.”

Another said missile interceptors in the future could face up to 200 decoys or objects at one time.

Such passages offer rare insight into what the agency thinks about the limitations of the system, Postol said.

“It looks like an honest engineer who was actually trying to solve a problem wrote this up, rather than a spin doctor,” he said.

Documents Address Future Challenges, MDA SaysA Missile Defense Agency spokesman acknowledged in an e-mail that countermeasures challenge the system.

“As we have said for years, countermeasures do now, and probably always will, present technical challenges for both current and future missile defense systems,” said spokesman Richard Lehner. 

The agency in a statement released to Global Security Newswire said, though, that the small business solicitations refer to potential challenges from future threats.

“They are not written to advertise limitations in existing systems or near-term block upgrades, but to focus attention on improvements that would add significantly to performance, lower cost, and add robustness against more complicated future threats (including sophisticated countermeasures),” the statement says.

Agency officials have argued that the system would likely face a primitive threat from any near-term ICBM aggressor and that against such a threat the system could be fairly effective.

A Washington Post article this month, for instance, suggested that the Missile Defense Agency estimates an 80 percent rate of effectiveness for the system, though the story indicated little about the assumptions underlying the estimate. It did suggest, however, that the number did not include data from early flight tests, which apparently include the only two tests using a type of decoy that critics said was found to closely resemble the dummy warhead to the infrared sensor.

“My guess is there are no decoys involved [in deriving the threat estimate], that they’re just asking can this thing hit an object in space with a reliability of x,” Postol said.   “If there are decoys there, the numbers very quickly go to zero. They can’t look inside the balloons, period.”

MDA Spokesman Lehner said that estimates and computations of effectiveness behind such numbers are classified, and said Postol “does not have access to highly classified information detailing our technical, scientific and engineering approach to defeating countermeasures.”

He also said the “most important data” used to derive such estimates comes from computer modeling and simulation and ground tests “that can postulate a huge number of likely scenarios and match system performance to determine expected effectiveness.”

Critics have charged that the administration must be assuming very simplistic or no countermeasures to arrive at such estimates, and add that models used for estimates may not be realistic as the agency has excluded advanced countermeasures from its testing regime (see GSN, June 8).

“The MDA has avoided the problem of target discrimination, by defining an ‘unsophisticated threat,’ that is, one or two missiles from a rogue nation involving no effective decoys countermeasures.  If the threat is defined as being nonthreatening, that ‘solves’ the problem,” Coyle said.  

“Since no flight intercept tests have been done with decoys that resemble the target RV, nor have flight intercept tests been done with radar chaff or other countermeasures, the system has no demonstrated capability to deal with the types of decoys or countermeasures a determined enemy would employ,” he said.

“Unfortunately, the MDA makes the artful assumption that North Korea … will not field any countermeasures that could defeat the U.S. interceptors,” writes Richard Garwin in an article due to appear in the November issue of Scientific American. 

“My assessment … is that the present missile defense approach is utterly useless against ICBMs of new or existing nuclear powers because midcourse countermeasures are so effective,” he writes.

Garwin and other experts have insisted that effective countermeasures are simple to build and well within the reach of an ICBM-armed country.

“The fundamental problem is that any country capable of building and successfully launching a nuclear-tipped ICBM can easily make and deploy many Mylar balloons ð— just like the ones you can buy in the supermarket ð— that look just like a nuclear warhead to a far away radar or satellite,” said Senator Reed. “And if there are many decoys and only one target, you have very little chance of hitting the target if you can’t discriminate.”

In that way, “An attacker could overwhelm the system by using antisimulation balloon decoys,” the Union of Concerned Scientists wrote in a critical report in April 2000. The 2000 report concluded, “Any country capable of deploying a long-range missile would also be able to deploy countermeasures that would defeat the planned NMD system.”

Proposed SolutionsTo try to solve the problem, the agency says it is simultaneously pursuing various technological solutions, including advances in radar and infrared sensors, lasers, signal processing, data fusion, and decision-making algorithms. A prominent approach, according to Coyle, is to have the kill vehicle carry different types of sensors, including infrared, radar and visible light, looking for differences between the suspected warhead and other nearby objects.

“Then they hope to fuse all that data together to pick out the target RV [re-entry vehicle] from the accumulated signals that the various sensors collect, and compare those signals with stored data files that have been precoded to predict what the actual target might look like,” he said.

“As indicated in the SBIR solicitation, some of these sensors don’t exist and would have to be invented and developed,” he added.

Postol said that solution offers little promise for solving the problem of a warhead hidden in a balloon, equating it to searching luggage at an airport without being able to open it or subject it to x-rays or sniffing dogs.

“It’s the equivalent to being restricted because of circumstances to only inspecting suitcases by vision,” he said. “You can use binoculars, or microscopes or rose-colored glasses … but you’re still basically looking at the outside of suitcase.”

Garwin argues there are other potential solutions to the midcourse intercept countermeasures challenge: space- or aircraft- based lasers for “popping” balloons or interceptors carrying gas to push the balloons, which would cause the decoys with less mass to move farther than the warhead. He said in an e-mail, though, that the Missile Defense Agency does not appear to be pursuing them and that they would require significant and costly changes to the planned system.

“Anyhow, that would be quite a different system, and we would begin its development only if MDA accepted the fact that they will be impotent if an adversary adopts AS [antisimulation] for the nuclear warheads on its early ICBMs,” he said.

September 29, 2004
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WASHINGTON — Documents published by the U.S. Missile Defense Agency over the past two years appear to confirm what experts have charged is a fundamental flaw of the national missile defense system the Bush administration plans to make operational in Alaska this year (see GSN, Sept. 22). 

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