When it comes to the Sea-Based X-Band Radar, Alaska’s loss is Hawaii’s $59 million gain.

Since the towering ballistic missile defense radar, topped by what looks like a giant golf ball, first arrived here in January 2006, it has become a loyal return visitor, shunning its foul-weather Aleutian Island home port so completely that it has never even moored there.

The 280-foot-tall SBX, as it is called, has "loitered" in the vicinity of Adak several times, the U.S. Missile Defense Agency said, but it has returned to Pearl Harbor 11 times and spent a combined total of more than a year and a half in port in Hawaii — becoming an instant tourist attraction every time.

Some airline pilots even point it out to passengers on their approach. The radar tied up at Ford Island on Dec. 22 for replenishment.

The Missile Defense Agency said it has spent about $59 million for repairs and maintenance at Pearl Harbor on the one-of-a-kind $1 billion missile tracking radar.

"When there has been a need to come into port, Pearl Harbor has offered the correct mix of labor and supplies to accomplish needed maintenance and repairs," the agency said in August.

The phased array radar inside the inflatable dome tracks U.S. and foreign missile tests with 45,000 transmission and receiving elements, and is so powerful it can see a baseball 2,500 miles away, according to the agency.

So far, it hasn’t docked anywhere but Hawaii, and after years of announcements and expectations that the SBX would become a fixture in remote Adak, the Missile Defense Agency now has taken a new tack: The agency said testing has shown that the SBX operates best in a "nomadic" mode.

"This means it is available for both operations and testing by having the ability to move around the ocean as necessary rather than moored at a fixed location," the Missile Defense Agency said in an e-mail.

Unused is a $26 million, eight-point mooring chain system installed in 2007 in Adak’s Kuluk Bay, according to the Alaska Dispatch newspaper.

Because of shore personnel and infrastructure requirements, "operating from the mooring is not currently as cost-effective as operating at sea with resupply," the missile agency said. "SBX will resupply from whatever port is best in the area where the mission has SBX operating."

Between 2009 and 2010, the SBX spent 396 continuous days at sea, officials said.

When it does head in, Hawaii has become the SBX’s home port by default. Ironically, in 2003, military officials considered but rejected permanently basing the SBX here. A spot three miles south of Kalaeloa was examined along with five other locations before Adak was selected.

Adak got the nod because it is between the "threat ballistic missiles" — presumably in North Korea — and the interceptor missiles in California and Alaska, Lt. Gen. Henry Obering III, then-head of the missile agency, said in a 2006 memo.

The island, with a population of about 165 in 2009, also has "outstanding facilities" — a protected ice-free harbor with pier space, fuel storage, housing and a large airport, Obering said. Adak was home to a naval air station until 1997.

RETURN VISITOR Like a loyal tourist, the massive $1 billion Sea-Based X-Band Radar platform keeps returning to Hawaii, becoming an instant focus of public interest every time it moors at Pearl Harbor. » Size: 240 feet wide and 390 feet long » Height: 280 feet from keel to top of radar dome » Displacement: Nearly 50,000 tons

The Missile Defense Agency is tight-lipped about the reasons for never mooring the SBX in Adak as planned in 2006, but the Coast Guard raised concern over operating a 280-foot-tall oil rig ship in the unforgiving Bering Sea, where waves routinely exceed 30 feet and winds top 130 mph.

Rear Adm. J.C. Olson, then the commander of Coast Guard District 17, which includes Alaska, said in a 2006 letter to the Missile Defense Agency that the SBX was not capable of "maintaining station" under such conditions, which posed a safety threat to the platform, crew and environment.

But Steve Stangl, a Boeing employee and site manager on the SBX, said there have been no weather-related operations problems.

In January 2007, on the SBX’s first trip up to Adak, the vessel ran into hurricane-force, 100 mph winds and 50-foot seas about 250 miles south of the Aleutian chain.

"I was impressed," Stangl said. "Even in the hurricane, I’m sitting in my office doing regular work, and I couldn’t tell (there was a storm outside). She’s built for stability."

The 120-foot tall radome is inflatable and made of materials similar to Teflon and Kevlar, officials said. Inside, it’s tan, and penetrating sunlight casts a gold glow over the 85-foot octagonal radar face.

Overpressure keeps the 18,000-pound dome inflated, and when the air lock door is opened, the pressure change feels like a descent in a jetliner.

Even in the 2007 hurricane-force winds, "the bag (radome) was just fine," said Ken Dube, the deputy X-band radar department head.

THE PIVOTING RADAR and its rotating carriage weigh 2,500 tons. The radar itself is studded with 45,000 geometrically placed radiating elements that are each about a foot tall.

"It provides us the power and the range that we need to execute our mission," Dube said.

About 85 crew members operate the SBX, which is run by Boeing, officials said. The Missile Defense Agency plans to transfer operations and sustainment responsibility to the Navy late this year.

The agency said fiscal 2010 sustainment costs — including repairs and maintenance at Pearl Harbor — were $167.1 million.

The SBX is piloted from a bridge that’s 133 feet off the water.

"We do look down on aircraft carriers when we come in," said Nathan Currier, the third mate.

The SBX is the principal sensor for ballistic missile defense while a rocket is in the midcourse of flight outside the Earth’s atmosphere, but can engage ballistic missile threats in all phases of flight, the missile agency said.

The radar has participated in multiple tests and the successful Feb. 21, 2008, shoot-down of a dying U.S. spy satellite, an undertaking code-named "Operation Burnt Frost." In June 2009, Defense Secretary Robert Gates ordered the SBX — which was in Pearl Harbor at the time — to sea as North Korea prepared a space launch across the Pacific.

The X-band radar is so powerful that officials said during an early planning meeting on Oahu that it could cause car airbags and fighter plane ejection seats to deploy.

The SBX also has been accused of causing garage door malfunctions, affecting pacemakers — even altering the weather, officials said.

Stangl, the SBX site manager, said the radar isn’t turned on within 75 miles of Oahu. Officials also said it is never pointed at land.

"We don’t run the radar close to land. I don’t think people understand that," he said.

There have been lots of upgrades and repairs over the years, and those will continue in the future.

BAE Systems said in 2007 that it had been awarded a contract for work in Pearl Harbor, including fuel oil tank cleaning, antenna installation, catwalk and ladder repairs, crane upgrades and additions, galley and scullery upgrades, and installation of a quick-launch recovery boat.

Another recent change is the decision to do away with the SBX’s 279-foot support vessel, the Dove, and resupply by helicopter, officials said.

The SBX is expected to leave Pearl Harbor by the end of the month, and for the first time since it was transported 15,000 miles to Hawaii on a heavy lift vessel in 2006, upcoming work will be done elsewhere.

About $9.4 million in work on the vessel’s thrusters and other modifications will begin in March at Todd Shipyards in Seattle, the agency said. Pearl Harbor is too shallow for the job.

In the meantime, the SBX seems to have gained acceptance at its informal home off Ford Island among all the Navy vessels that populate the harbor.

By contrast, there was a public outcry in Everett, Wash., when consideration was given to placing the radar vessel there.

"We don’t get complaints or issues (in Hawaii)," said Lt. Col. Rich Jaynes, the Missile Defense Agency’s product manager for the SBX.

He added that when the SBX pulls in, the agency gets numerous requests from local government officials and veterans organizations asking if they can visit the distinctive ship.

The Vidinha family was having lunch recently at waterfront Blaisdell Park in Waimalu, directly across the SBX.

"If it comes to Pearl, it must create jobs. That’s one thing we need — a lot of jobs," said Warren Vidinha, 59.

"I think it’s interesting," added his daughter, Palani, 33. "It’s something different."