UPDATE 2-US carries out successful missile defense test

(Adds statement from former weapons tester, paragraph 12)

By Jim Wolf

WASHINGTON, Sept 28 (Reuters) - A U.S. interceptor missile on Friday shot down a dummy warhead replicating an incoming North Korean missile in the seventh successful test of Boeing Co's (BA.N) long-range missile shield, the Pentagon said.

The Missile Defense Agency said in a statement it completed a test "involving a successful intercept by a ground-based interceptor missile designed to protect the United States against a limited long-range ballistic missile attack."

The interceptor missile was launched from Vandenberg Air Force Base on California's central coast, and its target was fired from Alaska's Kodiak Island.

"We got it," said test witness Riki Ellison, president of the private Missile Defense Advocacy Alliance, a group funded in part by missile shield contractors. "It was a success."

The $85 million test was a rerun of one that was supposed to have taken place in May but was scrubbed when the target misfired.

The test marked the sixth successful downing of a target in 10 full-fledged intercept tests since October 1999 in which knocking down the target was the primary objective, said Richard Lehner, a spokesman for the Missile Defense Agency.

On Sept. 1, 2006, the same missile system shot down a target. But the Pentagon said that test had been designed chiefly to collect flight data, not stop a target warhead. As a result, it was not included in the latest tally as reported by Lehner.

The Bush administration is building a layered shield to thwart ballistic missiles from countries like North Korea and Iran that could be tipped with chemical, germ or nuclear warheads.

Other components of the emerging anti-missile shield are based at sea, in the air and in space.

The United States want to install 10 ground-based interceptor missiles in Poland and a tracking radar station in the Czech Republic as a defense against a potential missile attack from Iran. Russia opposes the plan, saying it would upset a delicate strategic balance between major powers and threaten its own security.

U.S. critics say the missile defense tests prove little because they are highly scripted. An attacker would use decoys that would likely foil U.S. defenses, they say.

"Once again, there were no countermeasures or decoys used, making this test one of the simplest, easiest, flight intercept tests they've ever tried," Philip Coyle, the Pentagon's chief weapons tester under former President Bill Clinton, said in a statement e-mailed to Reuters.