U.S. Missile Defense Test Successful

The United States and Japan successfully tested an interceptor missile off Hawaii on Wednesday, further advancing their ability to shoot down enemy ballistic missiles in mid-flight.

The test aimed to check how well a Japanese-designed clamshell nose cone separated from a U.S.-designed interceptor missile. It was the first U.S. missile defense flight test to use Japanese parts.

The technology is for missile defense systems the United States and Japanese militaries are adopting amid worries about North Korean weapons development.

The U.S. test took place a day after North Korea test fired two of its own missiles. The short-range missiles never left Korean territory, officials said, but the test underscored the dangers posed by the country's longer-range missiles and professed nuclear weapons program.

The U.S. military is currently installing missile tracking radars and interceptor missiles on 18 U.S. Pacific Fleet ships. It is also equipping underground silos in Alaska and California with interceptor missiles.

During Wednesday's test, the USS Lake Erie guided missile cruiser fired a Standard Missile-3 interceptor into the atmosphere above the Pacific about 60 miles northeast of Kauai, the U.S. Missile Defense Agency said in a news release.

There was no live target for the interceptor missile. Instead, the SM-3 aimed itself at a simulated target inserted into Aegis Ballistic Missile Defense program computers.

Cameras mounted on the missile recorded the Japanese clamshell nose cone separating from the warhead.

The new style of nose cone allows the missile's warhead to spot its target more quickly, shortening the time the interceptor needs to shoot down the enemy missile.

Japan's Prime Minister Junichiro Koizumi praised the outcome.

"The success shows how much our technological capability has been enhanced," Koizumi told a group of reporters in Tokyo. "I hope that Japan and the United States will further advance their research."

The United States and Japan started jointly researching ballistic missile defense technology in 1999, one year after North Korea test-fired a long-range missile over northern Japan.

Pyongyang's surprise test alarmed Tokyo and spurred a strong Japanese interest in missile defense. Analysts say North Korea's ballistic missiles are capable of hitting all of Japan as well as Hawaii, Alaska and perhaps portions of the U.S. West Coast.

In 2003, Japan became the first U.S. ally to buy elements of the U.S.-designed missile defense system when it upgraded Aegis radars already on board its naval destroyers. Japan also bought SM-3 interceptors from the United States.

Japan's Defense Agency is also planning to buy 124 Patriot surface-to-air missiles by 2010.

Wednesday's test follows a successful test off Hawaii in November, when the Missile Defense Agency and the Navy intercepted and destroyed a warhead as it separated from its booster rocket.

That test marked the first time a ship at sea has shot down a multistage missile.

It also marked the Aegis ballistic missile defense system's sixth successful interception in seven attempts since 2001.

A sea-based test failed in 2003 when an interceptor missile missed its target.