A prototype interceptor rocket blew up a dummy warhead high over the Pacific in an explosive rendezvous marking the most complex test of missile defense technology so far, the Pentagon said.
The missile test, 225km above the Earth on Friday night, was the sixth for a ground-based missile defense system and the fourth success. The military is also developing other types of anti-missile systems; a ship-based interceptor rocket successfully hit a dummy warhead in a test earlier this year.
The interceptor in Friday's test, launched from Meck Island in Kwajalein Atoll in the Pacific near the equator, destroyed the dummy warhead at 9:41pm, Pentagon spokeswoman Cheryl Irwin said.
The test warhead was carried on a modified Minuteman II missile launched 7,700km away at Vandenberg Air Force Base in California.
Although complex, the exercise was still a developmental test and not an operational one, which would be more demanding. The dummy missile jettisoned three balloons to try to fool the interceptor. The previous test included only one decoy balloon.
The interceptor used its own sensors to pick out the warhead, track it and move in to collide with it, a Pentagon statement said.
Skeptics stressed that the missile defense system is still in its early stages.
"We have a long way to go before the final exam," said Chris Madison of the Center for Arms Control and Non-Proliferation. "I'm concerned that people have the impression, based on these tests, that we're almost to missile defense. Until we have operational testing, we'll have no idea whether we can get there."
The US government is pressing ahead with development of the anti-missile systems, saying the US needs a defense if a rogue country like North Korea develops and fires long-range missiles at US shores.
The full set of tests won't be finished until 2006 or 2007.