The monolithic radar that is key to the nation’s comprehensive missile defense shield and that has been sitting in Hawaii the past several months for repairs is now on its way through the North Pacific, heading toward its homeport of Adak at the end of the Aleutian Chain.

The sea-based X-band radar (SBX) is part of the Missile Defense Agency’s $43 billion program and is used to track missile launches. It looks like a giant golf ball sitting atop a 27-story, partially submersible oilrig.

The SBX was on course to Adak more than 10 months ago, but turned back to Hawaii after discovering ballast problems. It has never been to its homeport.

It is intended to detect the launch of missiles from hostile nations, like North Korea, and then guide U.S. missiles to intercept them.

The sophisticated system can pinpoint a ping-pong ball 3,000 miles away with its powerful, high-frequency radar, making detailed, long-range imagery possible at the North American Aerospace Defense Command (NORAD) on Peterson Air Force Base in Colorado Springs, Colo.

Rick Lehner, spokesman for the Missile Defense Agency in Washington, D.C., confirmed that the SBX left Honolulu Saturday.

He said the floating radar travels at about 5-6 knots, 24 hours a day.

Lehner said the SBX may not actually arrive in Adak for weeks, but it is moving toward the area.

He said mooring work is still to be finished on the island before the SBX can actually dock.

Before the SBX arrives in Adak, it is slated to be used in at least three test missile launches.

The first test is in March and will be launched from Vandenberg Air Force Base in California. Vandenberg is midway between San Francisco and Los Angeles on the California coast.

“The SBX will be out in the Pacific somewhere to track that launch,” Lehner said. “That test will not be part of the Kodiak system.”

But Lehner said that in April or May an actual intercept test from the Kodiak Launch Complex will take place.

“The SBX will track those missiles.”

Lehner said the forthcoming Kodiak test will be the first time the SBX will be “integrated in the fire control or shadow mode,” meaning the missile system still relies on radar in California but is being more fully used in the overall system.

However, another test planned for the fall of 2007 will use the SBX as the primary source radar, moving closer to complete reliance on it in the entire missile defense system.

The last missile test occurred in September when an interceptor fired from Vandenberg knocked out a target missile fired from the Kodiak Launch Complex that traveled 1,800 miles south some 200 miles above the earth’s surface before the hit.

The test was the first use of an early warning radar at Beale Air Force Base, about 40 miles north of Sacramento, Calif.

The California interceptor missiles are controlled remotely from the Joint National Integration Center in Colorado Springs, Colo., and travel at 18,000 mph.

The primary objective of the next Kodiak launch will also be to knock out the target missile.

The September intercept was the sixth hit for the overall program out of 11 attempts.

“The SBX is being developed in stages, one step at a time. It is a slow process,” Lehner said.

Lehner said the SBX is reaching a goal of full integration into the entire system.

“But it still may be a while before the SBX reaches its port,” Lehner said.

Mirror writer Bryan Martin can be reached via e-mail at bmartin@kodiakdailymirror.com.