US Marines gearing up to defend 'key' terrain near China are about to get a first-of-its-kind ship-hunting missile

• Marines did a first-of-its-kind test of the Navy-Marine Expeditionary Ship Interdiction System in June.
• NMESIS, a ground-based anti-ship missile, is set to be fielded for the first time later this year.
• It's one of many weapons Marines are developing with the goal of controlling "key maritime terrain."

Marines in California tested the Corps' new ground-based anti-ship missile in late June, just a few months before the service plans to field the weapon with a new unit in Hawaii, a milestone that reflects the Marine Corps' renewed focus on fighting alongside the US Navy to control important waterways in the Western Pacific.

The test-firing of the Navy-Marine Expeditionary Ship Interdiction System, known as NMESIS, from June 27 to 29 was announced in mid-July. Marines with the 1st Marine Division "successfully launched and engaged a simulated target off the coast of Southern California," the Corps said.

"NMESIS is the solution for the ground-based anti-ship missile capability," Staff Sgt. Derek Reddy, NMESIS team leader for the unit involved, said a video release. The June exercise was "absolutely imperative" and will help "set forth expectations" for the weapon's future use, Reddy added.

NMESIS is meant to complement the Corps' air-launched anti-ship missiles by allowing Marines to attack ships from areas where aircraft aren't able to operate. It emerged from the force redesign initiated by Gen. David Berger in 2019, shortly after taking over as Marine Corps commandant.

At that time, Berger said the Corps was "woefully behind" in developing ground-based long-range precision weapons.

A ground-launched missile that can track moving ships is central to plans to control what Berger and other Corps leaders call "key maritime terrain" — like the channels connecting the South China Sea to the wider Pacific — and to deny enemies access.

"The future NMESIS medium-range missile batteries are going to be operating in highly contested environments. We're shaping Marine Corps missile artillery and everything going forward" with the force-design plan, Reddy said.

'How do you deter with that?'

Work on NMESIS has moved swiftly, in part by drawing on technology that was already available. It was last tested in 2021 and has been fired three times overall.

The weapon pairs the Naval Strike Missile, which the US Navy already uses, with a launcher called the Remotely Operated Ground Unit for Expeditionary Fires, or ROGUE-Fires, which is a modified Joint Light Tactical Vehicle. The Corps says ROGUE-Fires vehicles can be operated with "a gamelike remote controller" and can autonomously follow a leader vehicle.

Berger, who stepped down as commandant in July, told lawmakers in April that the Corps is transitioning most of its 155mm howitzer batteries to NMESIS-equipped medium-range missile batteries "to conduct anti-surface warfare operations as a component of an integrated naval force."

The Corps has said that NMESIS will be fielded with the Hawaii-based 3rd Marine Littoral Regiment by the end of September, and it "is absolutely on track" for that, Berger said at the Modern Day Marine conference in Washington DC on June 27.

While the Marine Littoral Regiment's design is still being refined, the service says it will be "task organized" around an infantry battalion and an anti-ship missile battery and be able to disperse across islands and coastlines, remaining hard to detect while coordinating with friendly forces.

Marines with the 3rd MLR have already been practicing how they would employ NMESIS. During a major exercise in the Philippines in 2022, the unit conducted coastal-defense training that included passing "real-time targeting data" to HIMARS launchers standing in for NMESIS. During a major exericse in Hawaii months later, the unit simulated using NMESIS against an adversary vessel menacing a US aircraft carrier.

Fielding the weapon will yield further lessons, Berger said at the conference: "What are we going to learn? One, on the offense and the defense, how do you employ that system? How do you make it part of a system of systems? How do you deter with that?"

Berger added that Marines will learn how to use NMESIS on the go and to disperse the weapon — which can be operated remotely — as well as how to camouflage it in the field.

"I think the learning is going to happen really fast in 3rd MLR," Berger said. "NMESIS is going to teach us how do we control key maritime terrain — combined with the Navy, how do we do that? I think the learning begins this fall when we put it in the hands of a Marine unit."

Experts have raised doubts that NMESIS-equipped MLRs will be able to perform as expected in a conflict over Taiwan.

In a series of war games conducted earlier this year by the Center for Strategic and International Studies, a US think tank, participants found that political factors may prevent the unit from getting to Taiwan or the northern Philippines before a conflict and that even if it got to Taiwan, resupplying it during a conflict would likely be impossible.

The war games also showed that MLR forces in Okinawa would have more freedom to operate but that the Naval Strike Missile's 115-mile range would limit their ability to reach Chinese ships near Taiwan. (The Navy is pursuing a Tomahawk missile that could hit maritime targets up to 1,000 miles away, which the Corps could eventually acquire.)

"The problems of operating inside the Chinese defensive zone were insurmountable," the report on the war games said.

Despite that skepticism, Marines have no doubt about NMESIS itself.

"Oh, it hits ships," Gen. Eric Smith, who is now the Corps' acting commandant, said at the conference in June. "We've already tested it repeatedly, and it hits ships, because it's a sea-skimmer," Smith added, referring to the method of approaching a ship from the side near sea level to evade radar and other defenses.