The giant Sea-Based X-Band Radar has come and gone from Hawaii again as it embarks on another lengthy defense-of-the-homeland and missile defense testing mission.

But while here the “golf ball” resulted in over $47 million in repair and upgrade contracts benefiting Hawaii’s economy.

The more than $2 billion floating radar continues to perform tracking duty for the possibility of North Korean threats — as well as missile defense testing assignments — as the $1.9 billion Homeland Defense Radar-Hawaii struggles to find a home, either above the Kahuku Motocross Park on Oahu or at the Pacific Missile Range Facility on Kauai.

The one-of-a-kind “SBX” radar, built on a former oil rig, measures more than 280 feet from its keel to the top of the radar dome, is 240 feet wide and 390 feet long, and displaces nearly 50,000 tons when ballasted.

Inside its Kevlar-like inflated dome are more than 45,000 transmit/ receive radiating elements that make up a rotating radar array.

The SBX is capable of looking great distances, but with a small radar face, it has a relatively narrow field of view that makes it less than ideal for tracking incoming missiles.

The Missile Defense Agency said the unique radar platform returned to Ford Island on Sept. 10 after 350 days at sea.

Navy Cmdr. Scott McGowen, assistant to the agency director at U.S. Indo-­Pacific Command on Oahu, said in January that the mission was the third-longest time spent underway. The record was 582 days, with the radar returning to Hawaii on May 31, 2019.

While in port after that deployment, $24 million in repairs and upgrades were made, the Missile Defense Agency said. The three biggest jobs under the more than $47 million in recent work at Pearl Harbor were a radar cooling system upgrade, the upgrade of two variable-speed thruster drives, and hull coatings, said agency spokeswoman Heather Cavaliere.

Direct contracts with Oahu companies are estimated at $27.9 million, with the largest contractors being Pacific Shipyards International, Dorvin D. Leis Inc., American Electric Co. and Safway Services, Cavaliere said.

McGowen, speaking at a Chamber of Commerce Hawaii program, noted that a good portion of those contracts kept “the money within the community itself and (showed) that even during hard times like COVID, money is still able to come into our area to try to help during these times.”

Cavaliere said over 600 workers, mostly from Oahu, came aboard SBX for the work, with about 200 flying in and staying at hotels for the jobs.

About 72 crew operate the SBX at sea, with personnel rotated in and out as the radar continues to perform missions.

The Pentagon zeroed out its 2021 budget request for the Hawaii radar and another proposed for the Pacific, with the ground-based trackers seen as less of a priority in a wider review of sensor needs and increasing demand in particular for space-based sensors. The rapidly changing threat environment includes maneuvering hypersonic and cruise missiles.

McGowen noted that “due to a shift in priorities,” the Pentagon had postponed the development and fielding of the Hawaii radar for fiscal 2021.

Vice Adm. Jon Hill, director of the Missile Defense Agency, was asked in February 2020 about covering a Pacific radar “gap” without the two powerful ground-based radars.

“Today in that region you have forward-deployed AN/TPY-2 radars that handle that load,” Hill said, referencing a less capable radar. “We have a deployable SBX radar that handles that load. You’ve got (Navy warships) with their radars that are mobile and can be repositioned as appropriate.”

Despite the Hawaii radar uncertainty — at least for the Pentagon — Congress included $133 million in funding for the project in 2021.

McGowen said the Missile Defense Agency is “continuing advance planning studies and the environmental impact statement preparation to establish a preferred site, should the (Defense Department) and Congress support the project in future budget decisions.”

Two sites are still being considered for the Hawaii radar: one on Oahu at the Army’s Kahuku Training Area above the Kahuku Motocross Park, and the other in the southern portion of the Navy’s Pacific Missile Range Facility on Kauai.

The Kahuku site already has been the subject of community opposition. The Koolau Waialua Alliance, a grassroots group, recently said it is “concerned about the harmful effects” that the powerful radar could have on people, the environment, protected species and historic and sacred cultural sites.

Ship- and shore-based capability to defend against North Korean intercontinental ballistic missiles also is emerging with the development of the SM-3 Block IIA missile, which intercepted an ICBM-representative target for the first time in a November test.

Riki Ellison, chairman of the nonprofit Missile Defense Advocacy Alliance, expects Hawaii to get protection from such missiles that are either shore- or ship-based.

The 2021 National Defense Authorization Act requires the secretary of defense to report no later than March 1 on a “layered homeland defense” architecture that considers the use of SM-3 IIA missiles and the Terminal High Altitude Area Defense, or THAAD, in that plan.

Also required is an ex- planation of “how the cancellation or indefinite postponement of the discrimination radar for homeland defense planned to be located in Hawaii will impact the ability of such architecture to defend against current and future threats to Hawaii.”