The Missile Defense Agency said the air-launched ballistic missile was developed to replicate trajectories that hostile ballistic missiles could take in a real attack on the United States.

It was dropped by parachute from the rear of a C-17 aircraft about 800 miles northwest of the Pacific Missile Range on Kauai, Hawaii, the agency said.

"The missile's rocket motor then ignited, sending it on a planned trajectory over the Pacific Ocean," the agency said.

Missile defense radars and other sensors tracked the missile and relayed data to a command center at Colorado Springs, Colorado, it said.

Rick Lehner, a Missile Defense Agency spokesman, said ballistic missiles have been air-launched before but this was the first time the agency had launched one from the air as a target.

Critics have pointed to the absence of realistic operational testing has been a major flaw in the development of a system of ground-based interceptors to defend against long-range missiles.

They charge that the Pentagon has rushed to field the system without testing it first under conditions that approximate a real attack.

Rick Lehner, a Missile Defense Agency spokesman, said the new target missile could be used in flight tests of the ground-based missile defense system as early as the end of this year or next.

"What we can do is launch (the test missile) west of the Aleutians in international airspace and it would head in a trajectory that would make it more like a missile coming from North Korea for example," he said.

That would allow the use of a powerful Cobra Dane targeting radar in the Aleutian islands in a flight test for the first time, he said.

The radar was too remote to be of use in previous tests in which target missiles were fired over the Pacific from California and intercepted with missiles fired from the Marshall Islands.

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