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Tales from the Silent Service – U.S. Navy’s New SSN(X) Submarine

The United States Navy’s Virginia-class fast-attack submarines currently in service are among the newest in the fleet. They are nuclear powered and are equipped with four torpedo tubes to launch the Mk-48 Advanced Capability (ADCAP) torpedoes. A variant of the American heavyweight submarine-launched torpedoes, the 48s are designed to seek out and destroy deep-diving nuclear-powered submarines and surface vessels. The heavyweight, acoustic-homing torpedo utilizes sophisticated sonar and an all-digital guidance-and-control system, and its digital guidance system permits performance improvements to be made through software upgrades. The Mk-48 torpedo is designed to be launched from standard submarine torpedo tubes and can either be impulse launched or “swim-out” launched. The weapon is deployed on all USN submarines, including the Ohio-class Trident ballistic missile submarines and Seawolf, Los Angeles, and Virginia-class attack submarines. It is also carried by Canadian, Australian, and Dutch submarines. Mk-48 ADCAP torpedoes have the capability to be maneuvered post-launch from a submarine by wires attached to the torpedo guidance system. And they can also employ their own active or passive sonar sensors to execute programmed target search, acquisition, and attack procedures. The torpedo is designed to detonate under the keel of a surface ship rather than contacting its hull, breaking the keel and destroying its structural integrity causing it to break up and sink. In the event of a miss, it can circle back and home in for another attempt.

The Virginias can launch Tomahawk cruise Land Attack Missiles (TLAM) from vertical launch tubes (VLTs). The TLAM is a long-range, all-weather, jet-powered, subsonic cruise missile that is primarily used by the United States Navy and Royal Navy in ship and submarine-based land-attack operations, as well as Harpoon missiles, an all-weather over-the-horizon anti-ship missile that uses active radar homing and flies hugging the water’s surface to evade enemy radar defenses. The Virginias incorporate a number of new technologies and are among the stealthiest submarines currently in operation in the world.
The Navy designed the Virginias from the outset with a number of features not previously perceived in other submarines, such as a fiber optic fly-by-wire control system to replace the mechanical control system employed in previous submarines classes, as well as an innovative propulsion system that features the highly secretive electromagnetic signature reduction system that helps keep the submarine undetectable. Submarines, and all ships, produce their own magnetic signatures that make them vulnerable to detection by enemy weapons systems. Consequently, during submarine warfare, enemy ships and aircraft use increasingly sophisticated magnetic sensors and signal processing systems that measure disturbances in Earth’s magnetic field assisting in target detection.
Too, the long-standing mechanical drive is replaced by electric shaft motors eliminating the noise produced by the meshing of metal gearing. And, much like many electric cars (EVs) that don’t have traditional mechanical drive trains and transmissions, these totally electric drive submarines will be able to utilize the electricity produced by the steam turbines to propel the ship at whatever rate of speed is appropriate. Besides eliminating many noisy parts this revolutionary design also frees up a great deal more of the electric power produced by the onboard nuclear power plant for other shipboard uses.
The drive mimics that depicted in the 1990 submarine suspense film “The Hunt for Red October “where the Soviet Navy fielded a submarine with an innovative “caterpillar drive” that used nuclear-produced electricity to create magnetic fields that pushed water to the rear of the vessel, propelling it forward without any moving parts in the driveline and making it virtually silent and therefore undetectable by sonar. And while China has since claimed to have actually put that theoretical concept into practice on small applications, the U.S. Navy’s Columbia, Virginia and SSN(X) classes of submarines will likely be the closest approximation to that electrically powered “silent drive” in use anywhere in the world.
But, although the Virginia-class is possibly one of the most advanced nuclear-powered submarine designs in existence today, the Navy is already planning for its eventual replacement by the new SSN(X) or improved Virginia-class Attack submarine. And a recently published Congressional Research Service (CRS) document explains that the SSN(X) will be designed to counter the emerging threat posed by “near peer adversary” competition for undersea supremacy. And although the DOD hasn’t any formal definition of near-peer adversary, the term is common organizational jargon for references to the People’s Republic of China (PRC) and Russia.
Unlike the Virginia Class submarine, which was designed for multi-session dominance in the littoral zone, within a certain distance of shore, including surveillance, mine-clearing and support for landing operations and other types of combat shifting from water to ground. The SSN(X) will be designed for faster transit speed under augmented stealth conditions in all ocean environments and will carry an expanded inventory of weapons and diverse payloads. It will also be designed to retain multi-mission capability and sustained combat presence in denied waters, with a renewed priority in the anti-submarine warfare (ASW) mission against sophisticated threats in greater numbers. Too, the SSN(X) could be a “Drone Mothership” as it will play a chief role in utilizing undersea drones and may be able to launch and control multiple drones simultaneously from each submarine. The drones could have their own sonar systems for early warning and targeting enemy vessels. Also, the SSN (X) could be integrated with an unmanned in-flight aircraft that flies out ahead to gather targeting data for the submarine and then precisely guide its torpedoes to their targets. In its anti-submarine role, the SSN(X) will also have a mission to eliminate enemy submarines. And it will thrive in “contested environments” that are target rich in adversarial submarines. It will also have better sensors and sonar than the Virginia-class and be considerably quieter.
And although the Navy designed the Virginia-class for dominating a variety of environments and missions, the “SSN(X) will be designed with an eye on capabilities not yet seen in any other submarine classes. The Improved Virginia-class SSN(X) will retain the original Virginia multi-mission capabilities in contested deep water and littoral environments, though the class will also emphasize antisubmarine warfare in a way the original Virginias did not, namely via close coordination with friendly forces as well as other underwater vehicles.
One of the emerging challenges that modern submarine fleets must increasingly contend with is the threat posed by unmanned underwater vehicles (UUVs). And, like the original Virginia-class, the SSN(X) will remain primarily an anti-ship and antisubmarine warfare platform, and new, extremely long-range munitions could give the SSN(X) a huge advantage. Long-range torpedoes with a range of 200+ miles are one area that the Navy is reportedly exploring. At those extremely long ranges, targeting data would likely need to be supplied by an aerial platform, potentially a submarine-launched Unmanned Aerial Vehicle” (UAV), or perhaps by a maritime patrol plane like the Navy’s P-8 Poseidon. In that scenario, a submarine-launched long-range torpedo could complete its final run phase controlled or be directed not by the submarine it was launched from, but from an aircraft, a first ever in naval warfare.
The P-8 operates in the anti-submarine warfare (ASW), anti-surface warfare (ASUW), and shipping interdiction roles. It is armed with torpedoes, Harpoon anti-ship missiles, and other weapons, can drop and monitor sonobuoys, and can operate in conjunction with other assets, including the Northrop Grumman MQ-4C Triton maritime surveillance unmanned aerial vehicle (UAV).
While concrete and definitive details on the improved Virginia-class (SSN(X) submarine are as of yet scant, it will undoubtedly be one of, if not the most lethal submarines in existence with the potential to revolutionize undersea warfare.
The CRS SSN(X) report stated, “The Navy is examining three broad design options for the SSN(X), a design based on the existing Virginia-class SSN design and Columbia-class SSBN design, and a brand-new design, or a combination of the three.
“An industry official stated that the SSN(X) might have a beam (hull diameter) greater than that of the Virginia-class design of 34 feet, and closer to that of the Navy’s Seawolf-class SSN design and Columbia-class SSBN design of 40 and 43 feet, respectively.
The SSN(X) could also feature new technologies such as:
• Laser weapons
• New Conformal bow sonar
• Quantum technology
• Larger weapons stowage compartment to accommodate more systems such as weapons and UUVs

• More torpedo tubes to deploy the new weapons systems
• Very large flank sonar arrays
• Quieter electric drive propulsion
• X-rudder for better maneuverability
• Vertical Launching System (VLS) for cruise missiles and future hypersonic weapons
In essence, the Navy would like the SSN(X) to combine the best qualities of some of America’s most advanced submarines by blending the speed and munitions capacity of the Seawolf-class, the sensor suite and low acoustic signature of the Virginia-class, and the flexibility and longevity of the forthcoming Columbia-class submarine designs.
Hard to detect and harder to hit submarines are apex predators under the seas and given the increasing importance of the Indo-Pacific region, United States naval power, and by extension, submarine forces are a high priority for the Department of Defense.
Recent news reports raise the alarm bells about China’s naval power and point out that the People’s Liberation Army Navy is the largest in the world in terms of hull numbers. But while it is numerically superior to any navy, it is qualitatively inferior. American naval power would be essential if a conflict were to erupt in the Indo-Pacific, especially submarine capabilities. In the Next Generation Attack Submarine, it seems the United States Navy has found the most capable submarine ever envisioned.