A Japanese destroyer failed to knock down a drone yesterday off Kauai in the latest test of the Navy's ship-borne Ballistic Missile Defense System.

The $55 million failed intercept test, which took place about 250 miles off Kauai's Barking Sands, was paid for by the Japanese government. Japan's first attempt at an intercept last year was successful. Both targets were medium-range missiles.

Rear Adm. Brad Hicks, the U.S. Missile Defense Agency's Aegis ballistic missile program director, told reporters last night in a conference call from the Pentagon that the failure occurred within the “;final few seconds”; of the test, when the warhead of the interceptor missile lost track of the drone.

“;The weapons system and the crew performed superbly,”; Hicks told reporters.

The destroyer Chokai fired a SM-3 Block 1A interceptor missile at 4:24 p.m. from its forward missile tubes after detecting a drone fired from the Pacific Missile Range Facility at Barking Sands. However, two minutes later the Standard Missile-3 failed to intercept the drone.

Hicks said there was no explosion because the warhead carried no explosives and was supposed to destroy the drone upon impact.

The intercept was supposed to have taken place at an altitude of about 115 miles.

Hicks said a failure review board will be convened to determine why the intercept missile failed to hit its target.

“;I am confident that we will find the root cause,”; Hicks added, but he could not say how long the investigation would take.

The mission called for the Japanese destroyer to detect, track, engage and intercept the drone in its midcourse phase of flight.

The Chokai's SPY-1 radar had to differentiate between the drone's separating booster and simulated warhead.

In the same area on Dec. 17, the Japanese destroyer Kongo shot down a ballistic missile target, marking the first time that an allied naval ship successfully intercepted a target with the sea-based Aegis weapons system.

The Aegis ballistic missile defense system has been successful in 16 of 20 attempts, with the USS Paul Hamilton scoring the latest hit on Nov. 1. Eighteen U.S. cruisers and destroyers are armed with the system.

The Aegis ballistic missile defense ships are capable of intercepting short- to intermediate-range ballistic missiles.