U.S. Reinforces Undersea Warfare as USS Massachusetts SSN-798 Nuclear Submarine Nears Commissioning.

The U.S. Navy is set to reinforce its undersea warfare edge with the commissioning of USS Massachusetts (SSN 798), a Virginia-class Block IV nuclear-powered attack submarine entering service on March 28, 2026, in Boston. The addition delivers immediate gains in stealth, strike reach, and intelligence collection in contested maritime environments.

As undersea competition intensifies, USS Massachusetts expands the Navy’s capacity to track adversaries, hold targets at risk, and sustain covert operations across critical regions. The platform strengthens the U.S. ability to project power below the surface, where strategic advantage is increasingly decided.

Read also: U.S. Navy Sends USS New Mexico Virginia-class Submarine for Major Overhaul to Sustain Undersea Strike Edge

U.S. Navy USS Massachusetts (SSN 798), a Virginia-class Block IV nuclear-powered attack submarine, is pictured ahead of its March 28, 2026, commissioning in Boston, where it will formally enter active U.S. Navy service and expand the fleet’s operational undersea warfare capability. (Picture source: HII)

The Virginia-class program is central to replacing aging Los Angeles-class submarines while maintaining a technologically superior force against near-peer competitors. Designed for versatility, these submarines conduct anti-submarine warfare, intelligence collection, special operations support, and precision strike missions. With around two dozen units now operational, the class has reached a critical mass, enabling continuous global deployment cycles and persistent surveillance in contested waters.

USS Massachusetts belongs to the Block IV variant, which focuses on maximizing operational availability rather than introducing major structural changes. By reducing the number of major maintenance periods from 4 to 3 over their lifecycles, Block IV submarines can achieve up to 15 deployments. This improvement significantly increases time at sea and mission readiness without requiring additional hulls, a key factor as the Navy faces a projected shortfall in attack submarine numbers in the coming decade.

Technically, the submarine integrates advanced stealth features, including pump-jet propulsion, vibration-isolated machinery, and acoustic-damping coatings, that reduce detectability. Its AN/BQQ-10 sonar suite combines multiple sensor arrays to deliver enhanced detection and tracking performance, allowing the platform to operate as a forward intelligence node within joint force networks. These capabilities are essential for operating undetected in both deep ocean and littoral environments.

In terms of firepower, SSN 798 is equipped with 12 vertical launch system (VLS) tubes for Tomahawk cruise missiles and four 533 mm torpedo tubes for Mk 48 ADCAP torpedoes. This configuration enables precision land-attack strikes, anti-ship engagements, and anti-submarine warfare within a single platform. While newer Block V submarines introduce the Virginia Payload Module (VPM) to significantly expand missile capacity, Block IV boats prioritize sustained operational tempo and deployment efficiency.

Beyond Block IV and Block V, the U.S. Navy is now advancing the next evolution of the class through the Block VI program, signaling a significant increase in undersea strike capability. In Fiscal Year 2025, the Navy announced the procurement of three Block VI submarines as part of a planned total of nine to ten units. General Dynamics Electric Boat has already received a $1.3 billion contract for long lead materials, with a future multi-year procurement contract expected to formalize production.

Block VI submarines will further expand the Virginia Payload Module concept, incorporating six large Multiple All-up-round Canisters (MACs), four in the mid-body and two forward, each capable of carrying seven Tomahawk Land Attack Missiles. This configuration will give each submarine a strike capacity exceeding 40 cruise missiles, directly compensating for the planned retirement of four Ohio-class guided-missile submarines by 2030. The Navy estimates it will require at least 20 VPM-equipped submarines to fully offset this loss in undersea strike volume.

In addition to conventional strike capabilities, Block VI submarines are expected to integrate the Conventional Prompt Strike (CPS) hypersonic missile system starting around 2028. This will introduce a new dimension of prompt, long-range strike from the undersea domain, significantly enhancing the Navy’s ability to engage time-sensitive or heavily defended targets.

The Block VI design also incorporates improvements in stealth, propulsion efficiency, and sensor integration, along with new technologies that enable interaction across the full water column, from the surface to the seabed. This supports expanded mission sets including seabed warfare, intelligence operations, and infrastructure surveillance. A notable innovation is the planned deployment of tethered unmanned systems connected via fiber-optic cables, allowing submarines to relay real-time acoustic and sensor data to joint force networks across air, surface, and land domains.

At least one Block VI submarine is expected to be configured for specialized seabed warfare missions, potentially replacing the USS Jimmy Carter (SSN 23) 's unique capabilities. These missions include undersea espionage, cable operations, and deployment of special operations forces in denied environments, reflecting a growing strategic focus on the seabed as a contested domain.

The first Block VI submarines have already been named USS Potomac, USS Norfolk, and USS Brooklyn, with construction of the lead boat expected to begin under a FY2026 contract and delivery projected around 2034 to 2035. This timeline highlights the long-term nature of U.S. submarine force planning and the urgency of sustaining industrial capacity.

The commissioning of USS Massachusetts, therefore, illustrates a broader transformation of U.S. naval power. As commissioning directly marks the submarine’s entry into active service, SSN 798 immediately contributes to operational force levels. While Block IV submarines maximize deployment efficiency today, and Block V increases strike capacity, the future Block VI introduces a new level of undersea lethality, connectivity, and mission specialization, ensuring the U.S. Navy maintains a scalable, survivable, and increasingly networked submarine force capable of dominating future high-intensity maritime conflicts.

Written by Alain Servaes – Chief Editor, Army Recognition Group
Alain Servaes is a former infantry non-commissioned officer and the founder of Army Recognition. With over 20 years in defense journalism, he provides expert analysis on military equipment, NATO operations, and the global defense industry.