Pearl Harbor is getting a fourth Virginia-class submarine next week, adding to the high-tech firepower the Navy has said will accompany the rebalance to the Pacific.

The USS Mississippi, commissioned in 2012, will join the Hawaii, Texas and North Carolina here. Pearl Harbor is the sole Pacific home for Virginia-class subs, which cost an average of $2.7 billion, according to the Congressional Research Service.

The Pacific Fleet Submarine Force will be gaining greater undersea capability in the littorals, or offshore seas, where a lot of quiet foreign diesel electric subs operate.

China is building a modern and regionally powerful navy with a "modest but growing" capability for conducting operations beyond China’s near-seas region, the United States has said.

The newest, most capable U.S. vessels are moving to the Asia-Pacific region, Chief of Naval Operations Adm. Jonathan Greenert said recently.

New Navy P-8 sub-hunting and surveillance aircraft already have deployed to the region three times and the F-35 Joint Strike Fighter will be sent there as well, Greenert said.

Despite problems in the Middle East and Europe, "the long-range interests of (the United States) are in the Asia-Pacific," Greenert said.

The 377-foot Virginia-class submarines are capable of very precise slow-speed control. The Navy’s first major combat ship designed for a post-Cold War environment, the subs have six side-mounted sonar arrays, plus arrays in the bow, sail and nose, improving capabilities for eavesdropping and mapping the seafloor and minefields.

The subs carry Tomahawk missiles, have 12 Vertical Launch System tubes and four torpedo tubes.

They have "fly-by-wire" controls that improve ship-handling in shallow waters, a reconfigurable torpedo room to accommodate 30 special operations forces, and a nine-man lockout chamber for the rapid deployment of commandos from the submarine.

The first women on Virginia-class subs in the Pacific will serve on the Mississippi and Texas starting in fiscal 2016, Navy Secretary Ray Mabus told the Honolulu Star-Advertiser in July.

Hawaii hosts the largest number of attack submarines in the Pacific, with 14 Los Angeles-class subs listed on the Pacific Fleet sub force’s website as being home-ported at Pearl Harbor.

Pearl Harbor will actually see the arrival of two subs in coming days.

The Los Angeles-class submarine USS Jefferson City out of San Diego is heading to Hawaii from Guam for repairs and a two-year home-port change for a major overhaul, the Navy said.

The 360-foot sub, with a crew of about 140, was expected to be shifted to Hawaii in the spring or early summer for the work, said Pacific Fleet Submarine Force spokesman Cmdr. Brook DeWalt.

The sub left San Diego on April 9 on a western Pacific deployment and was expected to return to California six months later.

On the deployment, a "small" water leak was detected in a valve located in the sub’s nuclear propulsion system, DeWalt said.

"It’s coolant water so it’s just trace amounts of radioactivity in the water being collected on board the ship," DeWalt said.

The sub arrived in Guam on June 21. DeWalt said there were no issues with the crew, environment or populace.

It took some time to pinpoint the leak, which was first noticed as excess condensation, DeWalt said. Some specialized equipment had to be brought in to identify the source.

The question then became, "Do we fix it here in Guam? Do we go back and fix it when we get back home in San Diego?" DeWalt said. "The determination was, the expertise is here at Pearl Harbor."

The end result is the sub is being moved to Hawaii early, requiring a move by families as well.

"Being a sailor, it’s a dynamic environment that we live in and operate in," DeWalt said. "These kind of things can happen out there."