WASHINGTON — The Pentagon's missile defense system intercepted and destroyed a dummy warhead in space Friday, the first successful comprehensive test of its ability to protect the United States from enemy attack, officials said.
U.S. military officials were elated by the results after seeking to dampen expectations in the days leading up to the test. The system had been maintained on a partially operational basis to provide limited protection from North Korean ballistic missiles. But, as currently configured, it had not passed an important test until Friday.
"I don't want to ask the North Koreans to launch against us -- that would be a realistic end-to-end test. Short of that, this is about as good as it gets," said Air Force Lt. Gen. Henry "Trey" Obering III, director of the Missile Defense Agency.
About $43 billion has been spent in the last five years on the nation's missile defense, an effort that has produced mixed results. Development of a working system has been a top priority of the Bush administration, and in particular Defense Secretary Donald H. Rumsfeld; in the 1990s, Rumsfeld headed a commission on ways to counter nuclear missiles.
The $80-million test began Friday when a target missile was launched from Kodiak Island in Alaska at 10:23 a.m. Pacific time. Sixteen minutes later, an interceptor missile was launched from California's Vandenberg Air Force Base.
Seven minutes after the interceptor launch, the "kill vehicle" -- mounted atop the defensive missile -- collided with the target warhead and destroyed it over the Pacific Ocean, the military said.
The test was the first to use one of the U.S.-based interceptors that are supposed to protect North America. Previous tests have used interceptors in the Marshall Islands. The test also integrated a new radar based in California's Beale Air Force Base, 400 miles north of Vandenberg, that tracks incoming missiles, transmitting information to the interceptors in mid-flight.
Asked after the test how the military would rate the chances of shooting down a North Korean missile, Obering said the precise odds were classified, but he expressed measured confidence.
"I think we'd have a good chance," he said. "I feel a lot safer and sleep a lot better at night."
Obering described the test as "realistic" in terms of the trajectory and target it involved. But critics said the test was flawed because the target missile did not use countermeasures such as decoy projectile or multiple warheads that would confuse or mislead the kill vehicle.
"In reality, you could not rely on this system," said Stephen Young, a senior analyst at the Union of Concerned Scientists. "This is the best thing they have done to date. But it is still far below the standard of a real-world test."
Before the test, Pentagon officials had tried to lower expectations by saying that intercepting the decoy warhead was not an objective of the exercise.
"What we're trying to do is under-promise and over-deliver," Obering said.
Military and defense industry officials said that for this test, they were most concerned about seeing how a redesigned kill vehicle would work. The kill vehicle is supposed to spot the incoming ballistic missile and then differentiate between the missile's booster rocket and warhead. Finally, the vehicle must maneuver in and destroy the nuclear warhead.
Rumsfeld said Sunday that although he had confidence in the Missile Defense Agency, he wanted to see a test of the system, "where we actually put all the pieces together. That just hasn't happened."
In a statement Friday, Rumsfeld said he was pleased with the test but promised the system would be subjected to more rigorous examination.
"While today's test was a success, the test program is by no means complete," Rumsfeld said. "Tests will continue, some of which will be successful and some will not. This was a challenging test, and the tests will become even more challenging in the period ahead."
The next test is scheduled for December. Before Friday's intercept, the December exercise was supposed to be the one in which the military attempted to hit the target missile.
Future tests also will incorporate sea-based radar. And to make the next test more challenging, Obering said, the agency probably would add decoy vehicles to the target missile.
"We will begin to add what we call countermeasures," Obering said. "We will try to lay out different things that will try to confuse the kill vehicle as well the overall system."
Earlier testing of portions of the system involved warheads surrounded by decoys. But outside experts also questioned the validity of those tests.
Young, of the Concerned Scientists group, said any ballistic missile launched at the United States probably would have multiple warheads or a variety of countermeasures that would make the weapon hard to hit. He also said trying to shoot down a target missile at night would be a more difficult and realistic test.