The head of a U.S. missile defense advocacy group is urging the Pentagon to deploy "all available" defensive assets in the Pacific, including the giant Sea-Based X-Band radar docked at Ford Island, ahead of North Korea's planned rocket launch.

The Sea-Based X-Band Radar — more commonly known as the "Giant Golfball" after its white bulbous dome — "is the most powerful and most capable sensor to discriminate the debris, payload and a possible reentry vehicle in detail from a North Korean long-range missile or rocket launch traveling at extreme high speeds across the Pacific," said Riki Ellison, chairman of the Missile Defense Advocacy Alliance.

The alliance is a non-profit organization that supports a missile shield for the U.S.

Ellison today said he sent a letter to U.S. Defense Secretary Robert Gates urging the deployment of all available missile defense assets in the Pacific.

North Korea has said it will launch a communications satellite between Saturday and April 11, but the U.S. is concerned the North may be testing long-range missile technology.

The Pearl Harbor-based destroyer Chafee, which was in a South Korean port, is among U.S. and Japanese ships with missile tracking and/or shoot-down capability said to have been ordered to sea to monitor the North Korean launch.

Ellison said North Korea has declared two "clear zones" on either side of Japan for the first and second stages for debris falling from the rocket launch.

"The North Korea trajectory following that flight path would terminate close to Hawai'i if the rocket failed to achieve orbit or was a long-range ballistic missile launch," Ellison said.

Ellison said the Sea-Based X-Band Radar, or SBX, which he described as "one of the United States' most valuable assets and the best discriminating and tracking sensor for ballistic missile launches," has not been deployed and has been docked for the past several months at Ford Island.

The SBX was the main sensor in a Dec. 5, 2008 ballistic missile intercept test simulating a North Korean long-range missile threat and using current U.S. missile defense deployed assets, Ellison said.

"If deployed, the SBX can begin to emit its sensor 50 or so miles from Hawai'i and can become effective by providing sensoring information to the deployed long-range missile defense system in place today," Ellison said.

The 280-foot-tall radar platform, which is so powerful it could discriminate a baseball-sized object on the West Coast from the East Coast, remains in Pearl Harbor for $34 million in repairs. The SBX has 45,000 radiating elements within its pressurized dome.

The U.S. Missile Defense Agency in late February told The Advertiser the current round of work is scheduled to be done in June. The MDA also said June was when the SBX was next scheduled to leave Pearl Harbor for further testing.

Work proceeding now includes the addition of a second crane on the port side, improvements to the starboard crane, upgrades to the galley and the addition of equipment to facilitate mooring, MDA said.

The SBX, which the Missile Defense Advocacy Alliance's Ellison said cost $950 million to build and costs tens of millions annually to operate, has never pulled into port at its intended home of Adak, Alaska, the MDA said.

The radar known as the "giant golfball" arrived in Hawai'i in 2006 from Corpus Christi, Texas, for what was supposed to be a temporary stay.

In April 2006 the SBX returned to Pearl after a leak in its ballast piping forced it to abort a voyage north to Adak.

It returned to Pearl Harbor again in June 2007 from the waters of the Aleutian Islands for the repairs and upgrades that the MDA said now total $34 million.

In 2003, Pearl Harbor and Kalaeloa were considered home port possibilities, along with anchorages in California, Washington state, the Marshall Islands and two sites in Alaska, before Adak was selected.

The SBX has spent about 340 cumulative days in Pearl Harbor, and 791 days out in the Pacific for testing or operations, according to the MDA.

In March 2006, Coast Guard District 17 commander Rear Adm. James Olson sent a letter to the MDA saying operations in the Bering Sea were inherently dangerous, with winds of 80 knots and gusts of more than 120 knots, and sea states in the SBX operations area exceeding 30 feet.

"I urge you to consider safety as your first priority in this hostile environment," Olson said at the time, adding that he believed the SBX was not capable of "maintaining station" in the area.

While improvements continue to be made on the platform, the MDA said the SBX has "successfully met every operational test requirement to date."