Experts say improvements are needed in US missile defense system

The current US ballistic missile defense system provides “early, but fragile,” homeland protection from a potential missile launch from North Korea, but a more robust capability would guard against a strike from other small clandestine nuclear weapons states, according to a committee of experts convened by the National Research Council.

The NRC report , Making Sense of Ballistic Missile Defense, concludes that boost-phase missile defense should be abandoned and that the ground-based midcourse defense system, which deploys 30 ground-based midcourse interceptors at Fort Greely in Alaska and Vandenberg Air Force Base in California, requires a third interceptor base in the Northeast to be effective. All three bases should have smaller but more capable interceptor missiles, and they should make greater use of the five existing US early-warning radar sites by deploying X-band radar installations at those locations.

The information provided by IR sensors aboard the interceptors and the radars would extend the time available for identifying enemy missiles and allow for a “shoot-look-shoot” strategy, in which multiple successive interceptors can be shot at the target if necessary.

The 260-page report, released during an 11 September press conference, says that the improved system could be built for a cost that is within the $45 billion annual budget of the Missile Defense Agency , assuming that unnecessary programs are scrapped. In particular, the report calls for abandoning the MDA’s precision tracking space system (PTSS) , a proposed constellation of space-based IR sensors, because it is too costly and its purpose is better served by the improved synergies offered by the X-band radars and the interceptor sensors.

The report estimates the cost of the PTSS at $27 billion. But MDA director Patrick O’Reilly has called that estimate “considerably higher” than his agency’s calculations. And in testimony before the Senate Appropriations subcommittee on defense in April, O’Reilly called development of the PTSS satellites “the greatest future enhancement for both homeland and regional defense in the next ten years.”

The NRC committee also recommends that the Pentagon end all development efforts on boost-phase intercept systems because there would be too little time to intercept a missile in that phase of its flight. Although none are currently in development, NRC committee cochair L. David Montague told reporters that boost-phase proposals “keep coming up like a bad penny.” One, an airborne laser, remains in research-only status.

The committee says that any practical system to provide limited protection from ballistic missiles launched by North Korea or Iran against the US and its allies must rely primarily on intercepting a missile during the midcourse phase of flight, the period after the rocket motors have shut down and before reentry into the atmosphere.

But to intercept a missile in midcourse, interceptors will have to discriminate the target missiles from decoys, other countermeasures, and debris. “The hard fact is that no practical missile defense system can avoid the need for midcourse discrimination—that is, the requirement to identify the actual threat objects (warheads) amid the cloud of material accompanying them in the vacuum of space,” says the report.

Effective interception will also require that X-band radar observations be coordinated with data taken from optical sensors aboard interceptors. In the event of a miss by the first interceptor, the data and algorithms will improve the accuracy of successive interceptors.

Montague, a former president of the missiles division of Lockheed Martin Missiles and Space, said that all the components needed to provide the discrimination capability are currently available, but they have not been properly exploited. “We believe that the software requirements, sensor technology, and algorithms are understood quite well, and the phenomenology is understood quite well . . . by the people who need to know.”

However, for budgetary reasons, he said, the effort to develop an integrated system was terminated four or five years ago. The report urges the resumption of an “aggressive, balanced” R&D effort by the MDA that is “focused on the synergy between the X-band radar data and concurrent interceptor observations while closing on the threat.”

To defend deployed US forces, NATO members, and Asian allies from short-, medium-, and intermediate-range ballistic missile threats, the Department of Defense should continue investing in non-boost-phase antimissile systems such as Aegis , Terminal High-Altitude Area Defense , and Patriot Advanced Capability-3 . Those systems and radars are the components of the Obama administration’s NATO defense shield known as the European Phased Adaptive Approach.

The NRC committee largely endorses that program but says that one of its components, an interceptor base in Poland meant to shoot down Iranian long-range missiles headed for the US, would be less effective than the addition of an interceptor base in the Northeast.