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 golf ball" after its white bulbous dome — "is the most powerful and most capable sensor to discriminate the debris, payload and a possible re-entry 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 nonprofit organization that supports a missile shield for the United States. Ellison yesterday said he sent a letter to U.S. Defense Secretary Robert Gates urging the deployment of all available missile defense assets in the Pacific.

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.

Gates said on Sunday that if there is "an aberrant missile — one that was headed for Hawai'i," a shoot-down attempt might be made.

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," remains docked at Ford Island.

"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 is undergoing $34 million in repairs here. Officials with the U.S. Missile Defense Agency, which oversees the SBX, yesterday said work is continuing with scheduled shipyard activities. It referred all other questions to the Pentagon.