LIHU'E, Kaua'i — The Missile Defense Agency and the Navy yesterday successfully launched an interceptor missile that collided with a separating target missile, in the ninth successful intercept in 11 tests of the Aegis Missile Defense System, said Lt. Gen. Henry "Trey" Obering, Missile Defense Agency director.

"It was a no-notice launch in an operationally realistic environment," said Rear Adm. Brad Hicks, Aegis Ballistic Missile Defense program director. "We've got some happy people out here today."

In this test, a target missile was launched from the Pacific Missile Range Facility at Barking Sands, Kaua'i, at 4:40 p.m. yesterday. It was a separating target, meaning the warhead separated from the booster rocket in flight.

The Navy destroyer USS Decatur, which is equipped with the Aegis Missile Defense System, tracked the target, worked out a solution for intercepting it, and launched a Standard Missile-3 that slammed into the target midway through its flight — 100 miles high outside the earth's atmosphere and several hundred miles from Kaua'i. The impact occurred four minutes into the target's flight.

The Aegis system is the maritime part of the nation's missile defense initiative. It is built to intercept short- to medium-range ballistic missiles in flight. Previous tests have involved Aegis-equipped Navy cruisers. This was the first to test the system on a Navy destroyer.

In a simultaneous exercise, the Missile Defense Agency conducted a virtual anti-ballistic missile launch from another Navy ship, which was linked electronically with an Army missile defense system, THAAD, for Terminal High Altitude Area Defense.

"The THAAD ground-based radar at Barking Sands successfully tracked the launch and cued the USS Port Royal," an Aegis-equipped cruiser that then conducted a simulated launch against the same target. It was not the first time that THAAD and Aegis systems have been tested together, but it was another opportunity to test and improve on their interoperability, which will be of value to U.S. military units in the field, Hicks said.

The Port Royal also used the target launch to collect data on capabilities of the new Aegis Ballistic Missile Defense SPY-1B radar system, which is anticipated to be deployed in the field in 2010, Hicks said.

A key goal of this effort was to test the ability of a range of systems at different locations to track the missiles, and to communicate what they were tracking with each other. Besides the Decatur, the Port Royal and a Spanish Navy frigate, the Aegis-equipped Mendez Nunez participated. The Spanish ship, which conducted long-range surveillance and tracking of the test, was the third foreign vessel to participate in this series of Aegis tests. Previously, Japanese and Dutch navy vessels have been involved.

In the last Aegis test on April 26, the Aegis cruiser USS Lake Erie engaged two targets at once, firing a missile to defend itself from a rocket fired at the ship from an aircraft, while at the same time shooting down a short-range ballistic missile that had been fired from the ground at the Pacific Missile Range Facility.

The Lake Erie was able to track both targets, launch interceptors and successfully stopped them. In that case, the ship used a Standard Missile-2 to attack the aircraft-launched drone, and a Standard Missile-3 to collide with the non-separating target ballistic missile.

The Aegis Ballistic Missile Defense program is run by the Missile Defense Agency and the Navy. Lockheed Martin Maritime Services is the main contractor for the Aegis gear, and Raytheon Missile Systems the prime contractor for the Standard Missile program.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.