Ready or not, it's go for launch
Although missile defense was a high priority of the Reagan White House, it seemed an orphaned concept after the Cold War ended. But in 1998, a commission headed by Donald Rumsfeld before he became defense secretary declared that within a few years, North Korea could build a missile capable of reaching the United States. Less than two months later, as if to underscore Rumsfeld's report, North Korea tested a ballistic missile that streaked over Japan. The third stage failed, and the missile barely had room to carry a warhead. No matter. Missile defense was revitalized. And after the 2000 election, proponents found a strong ally in the White House.
The concept for a ground-based system is elegantly simple, if technologically difficult. If an adversary launched an ICBM toward the United States, advanced satellite sensors would quickly alert the U.S. Northern Command at Cheyenne Mountain in Colorado. A three-stage interceptor rocket topped with a "kill vehicle" would be launched in response. A supersensitive, ship-based X-band radar system--assisted by a Cold War radar in the Aleutian Islands called Cobra Dane and by ship-based Aegis radars--would track the incoming missile, guiding the interceptor. More than 100 miles above the Pacific, the sensor-packed kill vehicle would home in on the warhead and destroy it in a 15,000-mph collision.
So far, the technology has been tested eight times, by launching an interceptor from Vandenberg toward a mock warhead fired from thousands of miles away in the Pacific. Five of the test interceptions succeeded, proving the concept, Norgaard says. "We believe we have demonstrated the capacity to hit to kill."
But many components needed for a working system either are not ready or haven't been fully tested.
Sensors needed for a new satellite system that would improve the military's ability to detect enemy missile launches won't be delivered before July, and possibly not until mid-2005.
The X-band radar is under construction in Texas and won't be in service until December 2005. Air Force Lt. Gen. Ronald Kadish, the head of the Missile Defense Agency, says he is "absolutely confident" that the Aegis radars and the recently upgraded Cobra Dane will suffice in the meantime. Some experts aren't convinced, however, that radars built for other purposes can track an ICBM with enough precision to guide an interceptor.
Delivery of a new three-stage booster rocket is behind schedule. So far, the rocket has not been tested against a mock warhead, though an intercept test is scheduled for this summer.
The sensors on the kill vehicle malfunctioned in the most recent intercept test, in December 2002. It's uncertain if the flaw has been fixed.
Critics also note that the tests so far have all been tightly choreographed. The pace is slower than a real engagement because current interceptors use a more plodding, two-stage booster. A global positioning system aboard the target guides the interceptor. And the sensors are told in advance how to identify the warhead. "It only works if you assume that the other side plays along," says Richard Garwin, a physicist and weapons expert who was a member of the Rumsfeld commission.
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