In the face of increasing North Korean ballistic missile threats, the Pentagon is studying beefing up Hawaii’s defenses by switching an “Aegis Ashore” missile system and launcher on Kauai from testing to operational mode and adding radars to track incoming missiles, a missile defense expert said.

Riki Ellison, chairman of the nonprofit Missile Defense Advocacy Alliance, said the study is due out by August. But in the meantime, he said, Hawaii lags in ballistic missile defense while the United States pours billions into the defense of Alaska and the mainland, Guam, Japan and South Korea.

“(Hawaii) is the military command of all of the Pacific. It is targeted, let’s not fool ourselves,” Ellison said.

Ellison said there is no reason not to “operationalize” the Aegis Ashore facility on Kauai for the ballistic missile defense of Hawaii. The facility, which tracks incoming missiles and fires interceptors, was put in place at the Pacific Missile Range Facility to test defensive Aegis Ashore sites for Romania and Poland.

“We’re sitting here with this capability that we’ve already paid for as taxpayers,” Ellison said. “Why would you not do this? I thought we would learn from Pearl Harbor. You’ve got to be able to protect Hawaii.”

Ellison and Navy Capt. Bruce Hay, commander of the PMRF, spoke Tuesday at a Chamber of Commerce Hawaii briefing titled “Only One Shot: Hawaii Missile Defense” in reference to the one-shot chance Hawaii has from ground-based missile interceptors in Alaska and California that protect the United States.

The military has no opportunity for a second shot with a ground-based interceptor due to the distance to Hawaii, the Missile Defense Advocacy Alliance said previously.

The Chamber event at the Pacific Club was not open to the media, but Ellison spoke to the Honolulu Star-Advertiser afterward.

The “Aegis Ashore” site on Kauai uses a land-based SPY-1 radar and SM-3 missiles like those on at least 33 U.S. Navy Aegis ships with ballistic missile shoot-down capability. On Kauai the radar and vertical launch system are separated, rather than in close proximity.

The U.S. Missile Defense Agency said in 2013 when the Kauai site was first powered up that the “Aegis Ashore facility is a test facility, and is not planned as an operational site.”

But advances in North Korean warhead miniaturization and rocket technology have lawmakers and the Pentagon reconsidering Aegis Ashore use.

U.S. Rep. Tulsi Gabbard, a Hawaii Democrat, noted at a March 22 House Armed Services Committee hearing that North Korea had test-fired five short-range missiles just the day before.

“In Hawaii we have a site for the Aegis Ashore at the Pacific Missile Range Facility, and I and others on the committee are pushing towards operationalizing that to increase that protection,” Gabbard said.

At a March 10 Senate Armed Services Committee hearing, meanwhile, one senator noted that North Korea threatened a pre-emptive nuclear strike that would reduce Seoul into a sea of fire and ashes.

Adm. Bill Gortney, head of U.S. Northern Command, charged with homeland defense, said he assessed a North Korean attack on the United States to be “unlikely” — unless leader Kim Jong Un perceived an imminent threat to his regime’s survival.

Gortney said North Korea could hit Hawaii, Alaska and the mainland with an intercontinental ballistic missile. He also said it was prudent to assume North Korea has the ability to miniaturize a nuclear weapon and put it on an ICBM.

Ellison said Aegis Ashore would be part of a layered defense that is needed to provide more than one shot at an incoming missile and with the ground-based missiles having multiple failures in tests.

An operational Aegis Ashore site in Hawaii could provide at least two more shot opportunities in the terminal phase of an incoming North Korean ballistic missile, according to the Missile Defense Advocacy Alliance.

Pearl Harbor has a handful of destroyers and cruisers with ballistic missile shoot-down capability, but they have “other missions than to sit there on a picket line and defend (Hawaii),” Ellison said.

He said the Pentagon is spending many millions on a long-range discrimination radar in Alaska.

“We just spent all that money on that to give the United States a much better probability of a kill” using the 30 ground-based interceptors, Ellison said. The military spent many more millions on a Terminal High Altitude Area Defense to protect Guam, he said.

“We spent much more than that in Japan helping the Japanese defend Japan,” he said. “We’re doing that in the Republic of Korea.”

But in Hawaii there’s a missile defense gap, he asserts.

Ellison said it’s also important to get a missile-discriminating radar in Hawaii, and part of the Pentagon study is examining that need.

The Sea-Based X-Band Radar can be used more, he maintains, but it’s “not persistent. You have to tow it all the way out to Midway.”

The long-range radar in Alaska isn’t useful for Hawaii because of Earth’s curvature, he said.

The Navy said the Air and Missile Defense radar suite being developed for multiple ship classes is to be tested at the Pacific Missile Range Facility in the spring. Ellison said the radar is modular and can be built up “and you’ve got capability there … without having to wait four years to bring something in.”

Ellison said the Aegis Ashore site could be switched between operational use and testing.

Kauai Mayor Bernard Carvalho Jr., who also attended Tuesday’s meeting, said, “We’re testing the site right now, and so now (it) is moving it up a step to make it more operational.”

Carvalho supports operational use, which he said also would bring some jobs, although no specific numbers were discussed Tuesday.

“It’s a positive thing,” he said. “We could go back and forth from training and testing.”