US Navy plans SSN(X) nuclear attack submarine as underwater drone mothership to extend seabed warfare.

The U.S. Navy announced at the Naval Submarine League conference in Arlington, Virginia, that its next-generation SSN(X) nuclear-powered attack submarine will be built as a mothership capable of launching, recovering, and controlling multiple unmanned underwater vehicles (UUVs). According to Rear Adm. Andrew Miller, Director of the Undersea Warfare Division, the Virginia-class successor will integrate dedicated autonomous vehicle handling, recharging, and command-and-control infrastructure directly into a wider hull combining Seawolf-class speed and weapons capacity, Virginia-class acoustic stealth, and Columbia-class operational availability.

Unlike the Virginia-class, which has to retrofit existing torpedo tubes and missile launchers to handle unmanned underwater vehicles, the SSN(X) will feature a wider hull with built-in infrastructure specifically designed to launch, recover, recharge, and control underwater drones without sacrificing its weapons capacity. (Picture source: US Navy)

On November 12, 2026, USNI News reported that the U.S. Navy outlined plans for its SSN(X) nuclear-powered attack submarine to operate as a mothership capable of deploying, recovering, and controlling multiple unmanned underwater vehicles (UUVs), making autonomous underwater operations a central requirement of the Virginia-class successor. Unlike the Virginia-class, the SSN(X) would therefore incorporate autonomous vehicles into its basic architecture, rather than adapting existing torpedo rooms and missile launchers to accommodate equipment for which they were not originally designed.

At the Naval Submarine League conference in Arlington, Virginia, Rear Adm. Andrew Miller identified five priorities for the SSN(X): higher flank and tactical control speeds, improved operational availability, increased lethality, superior stealth and survivability, and integrated command and control for robotic underwater vehicles. The U.S. Navy completed its analysis of alternatives in November 2025, secured requirements approval in March 2026, and is seeking Milestone A authorization before the end of 2026. The first SSN(X) is planned for procurement in the early 2040s, with Congressional Budget Office (CBO) calculations assuming 10,100 tons of submerged displacement and $8.7 billion per submarine in FY2024 dollars, against the U.S. Navy's $7.1 billion estimate.

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The SSN(X) is intended to combine the submerged speed and weapons capacity of the Seawolf-class, the acoustic characteristics and sensors of the Virginia-class, and the operational availability of the future Columbia-class, while addressing limitations in weapons stowage, electrical capacity, and maintenance accessibility. The original Seawolf design displaces 9,138 tons submerged, measures 107.6 meters, and carries eight 660 mm torpedo tubes with capacity for 50 weapons, compared with the Virginia's four 533 mm tubes, 10.4-meter beam, and original 7,800-ton displacement. Increasing the hull diameter to approach the Columbia-class's 13.1-meter beam would therefore provide more room for UUV handling, additional weapons, electrical equipment, and internal servicing.

At 10,100 tons, the SSN(X) would also displace 29.5% more than an original Virginia-class submarine, although its final dimensions, speed, and weapons capacity remain subject to design decisions. Greater hydrodynamic and electrical margins would support future equipment without extensive hull modifications, while reduced repair duration would increase fleet availability. For comparison, raising operational availability from 60% to 70% across 50 U.S. submarines would increase the number available at any given time from 30 to 35, illustrating the fleet-level value of maintenance improvements. The U.S. Navy's current transition toward submarine-hosted UUVs began with medium autonomous vehicles whose launch arrangements were substantially simpler than their recovery procedures.

How the U.S. Navy is developing underwater drones that can return to submarines

By November 2022, the Unmanned Underwater Vehicle Squadron 1 had tested nine Razorback drones derived from Huntington Ingalls Industries' Remus 600 family, each weighing 600 pounds and initially requiring a dry-deck shelter and divers for recovery, limiting the submarine's ability to conduct repeated autonomous missions. A $358 million effort involving Leidos and L3Harris also addressed related medium-UUV requirements for submarine reconnaissance and explosive ordnance disposal. For instance, in July 2026, L3Harris received a Defense Innovation Unit contract for a Torpedo Tube Launch and Recovery system using a removable sleeve inside a standard 533 mm tube, allowing an Iver4 900 to depart and return underwater.

In 2026, USS Delaware (SSN-791) became the first U.S. nuclear attack submarine to achieve operational capability with Remus 620 launch-and-recovery equipment incorporating Yellow Moray docking technology, following a related British demonstration aboard HMS Astute in 2025. However, recovery remains the main difficulty, as the submarine must guide the returning UUV into a narrow tube while controlling its relative position, approach speed, and alignment without surfacing. The Remus 620 and Iver4 900 established different operating envelopes for submarine-supported reconnaissance and seabed surveys. Huntington Ingalls Industries' Remus 620 offers 110 hours of endurance and 275 nautical miles of range, equivalent to an average 2.5 knots over its stated maximum range and endurance. At that average speed, a 100-nautical-mile outbound transit and return would consume 80 hours, leaving a theoretical 30 hours for surveying before accounting for reserves and sensor power consumption.

For its part, L3Harris' Iver4 900 uses titanium and carbon-fiber construction, operates to 300 meters, and accepts interchangeable sonar, mine detection, seabed mapping, and electronic intelligence payloads. Its nickel-metal hydride batteries provide 20 hours and 40 nautical miles, increasing to 40 hours and 80 nautical miles with lithium-ion batteries. Consequently, larger autonomous submarines are being pursued for missions that exceed the payload and endurance limits of these tube-launched vehicles, including Boeing's Orca extra-large UUV, the Navy's Snakehead effort, and Anduril's Dive-XL. Anduril was also selected in March 2026 for the Combat Autonomous Maritime Platform project, although these larger vehicles require deployment and recovery arrangements separate from standard submarine torpedo tubes. The U.S. Navy is also examining dedicated submarine payload launchers that can repeatedly deploy and recover autonomous vehicles without relying exclusively on existing torpedo rooms.

How the SSN(X) could launch, recover and support multiple underwater drones

On July 29, 2026, it initiated industry engagement involving General Dynamics Electric Boat and Newport News Shipbuilding, with concepts expected to address vehicle handling, maintenance, recharging, and secure data transfer. The existing Virginia Payload Module adds a 25.6-meter hull section containing four large-diameter tubes, each accommodating seven Tomahawk missile cells, increasing total vertical-launch capacity from 12 to 40 missiles. However, unlike missile launchers, recoverable UUV compartments require docking interfaces, internal handling machinery, electrical connections, and access for servicing vehicles between missions. A horizontal recovery arrangement would favor torpedo-tube-sized drones, while larger vertical compartments could accommodate different vehicle dimensions at the expense of additional structural and handling requirements.

Underwater acoustic communications also impose bandwidth and latency restrictions, making onboard navigation and autonomous mission execution necessary when vehicles operate beyond reliable contact with their submarine. Consequently, the SSN(X)'s UUV capacity will depend on available internal volume, charging infrastructure, recovery arrangements, and the number of vehicles that can be serviced without displacing conventional weapons. The resulting operational capability is particularly relevant to conduct reconnaissance and seabed surveys beyond the submarine's immediate sensor coverage, particularly in confined waters such as the Miyako Strait, Bashi Channel, and South China Sea approaches. UUVs equipped with side-scan sonar, synthetic aperture sonar, or hydrographic sensors can survey mine-like objects, map seabed features, and collect temperature, salinity, and depth information relevant to acoustic propagation.

They can also inspect underwater cables, pipelines, and fixed acoustic installations without requiring the nuclear submarine to approach each location. The Remus 620's range permits substantially longer survey missions than the Iver4 900's configurations, but the usable operating radius must include outbound transit, survey activity, return, and battery reserves. Deploying several underwater vehicles would permit simultaneous collection from different positions, although limited underwater communication bandwidth prevents this from automatically becoming continuous real-time surveillance. Sustained operations would subsequently require enough UUVs to rotate between missions, recovery, maintenance, and recharging. The number carried also creates a weapons-stowage trade-off, making dedicated UUV compartments potentially important for the SSN(X)'s final design.

How China's expanding underwater drone fleet is shaping the SSN(X) program 

For its part, China is developing its autonomous underwater capabilities at both substantially larger and smaller scales than the current American submarine-launched medium-UUV programs. Beijing displayed the HSU100 and AJX002 extra-large vehicles on September 3, 2025, while separate 35- and 45-meter autonomous submarine designs, estimated at 400 to 700 tons, have undergone testing near Hainan. In September 2026, a 205-meter auxiliary vessel also appeared at Hudong-Zhonghua in Shanghai with 12 lifting masts and a stern cradle potentially accommodating 50-meter underwater vehicles. A second suspected UUV mothership appeared near Guangzhou in October, measuring 150 meters and incorporating six lifting masts, a stern opening, and an enclosed hangar.

These arrangements could transport and service large autonomous submarines without requiring them to expend their propulsion endurance during long transits, although the ships' exact operational roles remain unconfirmed. China also tested 116 TH-618 underwater drones in August 2026 inside a 164-by-65-foot pool. Each 11-pound vehicle measures 2 feet long, offers eight hours of endurance and more than 18 miles of range, and participated in 34 minutes of coordinated maneuvers covering more than 1,600 feet. The trial demonstrated that China can now coordinate more than 100 underwater drones, but under controlled conditions rather than sustained open-ocean operations. The SSN(X) program must therefore address both the increasing undersea competition with China and the industrial cost of maintaining a nuclear submarine force equipped with autonomous vehicles.

Rear Adm. Chris Cavanaugh warned that China could potentially construct another 20 to 40 comparable nuclear attack submarines over the following decade while improving their individual capabilities, alongside expanding seabed mapping and the proposed Transparent Ocean surveillance architecture in the Western Pacific. Russia's Poseidon nuclear-powered, nuclear-armed underwater weapon, for its part, represents more of a long-range strategic strike capability rather than a recoverable reconnaissance system. For the U.S. Navy, Electric Boat and Newport News Shipbuilding must now balance Virginia-class production, Columbia-class construction, maintenance demands, and SSN(X) development within a specialized industrial base.

The difference between the Navy's $7.1 billion estimate and CBO's $8.7 billion calculation also equals $1.6 billion per submarine, or $32 billion across 20 vessels in constant FY2024 dollars, excluding their UUV inventories and supporting infrastructure. Delaying SSN(X) from FY2035 into the early 2040s also extended the reliance on Virginia-class submarines while creating a longer interval between major submarine design programs. Ultimately, the operational return on SSN(X) investment will depend on deployable submarine numbers, embarked UUV inventories, vehicle endurance, recovery reliability, mission turnaround, and the amount of surveillance information generated per deployment, rather than the submarine's launch capacity alone.

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Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, South Korea, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.