A US navy missile over the Pacific intercepted a target missile, which the military on Thursday said was the fifth successful test of a system to shield North America.
The navy said the Standard Missile 3 interceptor is designed to destroy medium- to long-range missiles on the fly.
The navy launched the target missile from the Hawaiian island of Kauai and launched the Standard Missile 3 from the USS Lake Erie about 160 kilometers (100 miles) away, according to a statement.
The Aegis missiles collided, using the same technology as a ground-based system designed to destroy long-range missiles and used by army’s Patriot system.
Also Thursday, Canada announced that it would not participate in the US system because of broad domestic opposition.
Ottawa had been mulling its stand on the US missile defense program for more than a year, and political analysts expected the decision.
The Pentagon is seeking a 20 percent boost in funding for the program, from 7.7 billion dollars this year to 9.2 billion dollars in 2005.
Plans calls for deploying 20 ground-based interceptor missiles and up to 10 sea-based missiles by the end of fiscal 2005.