What’s in a name? For nineteen planned US nuclear-powered submarines (SSNs), the US Navy’s August 3 decision to reclassify them as guided missile submarines (SSGNs) is more than a bureaucratic change. The new label reflects their growing role in spreading strike power across the fleet. But here is also a broader lesson: Innovation can mean giving familiar technology a new mission.
We asked Joshua VerGow, senior fellow with our Forward Defense program, and Abigail Rudolph, the program’s assistant director, what the change means for the future of undersea warfare.
1. What does the reclassification change?
When most people hear that the Navy is redesignating nineteen submarines, it might sound like the kind of bureaucratic change that only matters to people inside the Pentagon. It’s much more significant than that. What the Navy is really doing is signaling that it’s changing how it intends to fight.
To understand why, it helps to know how the Navy classifies submarines. An SSN is a nuclear-powered attack submarine. Traditionally, these boats are designed to hunt enemy submarines and surface ships, gather intelligence, support special operations forces, and strike targets on shore using a relatively limited number of cruise missiles. An SSGN, by contrast, has historically referred to a nuclear-powered guided missile submarine built around delivering a much larger volume of long-range precision strikes. While both types can launch missiles, the distinction has generally reflected the submarine’s primary mission rather than simply the hardware onboard.
What’s interesting is that these submarines themselves are not fundamentally changing. The hull is the same. The reactor is the same. The crews are essentially the same. What has changed is how the Navy intends to employ them. Beginning with the Block V Virginia class, the Navy is adding what’s called the Virginia Payload Module, which inserts four additional payload tubes into each submarine. Each tube can carry seven Tomahawk cruise missiles, which means that each boat will go from carrying twelve Tomahawks to as many as forty. That amounts to more than tripling its long-range strike capability without requiring an entirely new submarine design.
In addition, the redesignation tells commanders, allies, industry, and potential adversaries that the Navy increasingly views distributed, survivable strike capability as a central mission for its undersea fleet.
2. How does this decision fit in with the US Navy’s Distributed Maritime Operations concept?
At its core, Distributed Maritime Operations (DMO) is the Navy’s recognition that warfare has changed. It has become much harder to hide large military formations than it was twenty or thirty years ago. Between satellites, drones, artificial intelligence, long-range sensors, and precision weapons, concentrating your combat power in one place has become increasingly risky.
DMO seeks to solve that problem by distributing combat power across many platforms operating over much larger distances while still allowing them to fight as a coordinated force. Many different platforms (surface ships, submarines, aircraft, and unmanned systems) can each contribute to sensing, decision-making, and striking targets. The objective is to create a force that is more resilient, more difficult to track, and much harder to defeat.
With the DMO as a starting point, the submarine redesignation becomes even more significant. Increasing the strike capacity of Virginia-class submarines allows offensive capability to be spread across more platforms, and it does so without building an entirely new class of ships. It gives commanders more options while making it considerably harder for an adversary to eliminate the Navy’s ability to conduct long-range precision strikes.
3. What does this reveal about how the US military plans for its future force?
Perhaps the most important lesson from this decision has little to do with submarines specifically. For us, it illustrates that innovation in the military is not always about inventing a new technology. Sometimes the greatest competitive advantage comes from employing existing technology in new and creative ways.
The Virginia Payload Module is neither a new nor revolutionary invention. None of the underlying components suddenly became more advanced overnight. What changed was the Navy’s recognition that combining these existing capabilities in a different operational concept creates a significantly different military effect and a much bigger problem for a potential adversary.
There is currently a big debate taking place among US military planners and policymakers. One side of this debate argues for prioritizing smaller amounts of highly capable, technologically advanced, and very expensive capabilities—what the Pentagon calls “exquisite” systems. The other side insists that mass quantities of attritable systems, such as drones, are more important. Limited resources—time, workforce, foundries, government contracts—mean that not everything can be built at once.
In reality, it’s not just one or the other. Both exquisite and attritable systems are needed for operational effectiveness. Repurposing existing platforms offers some relief: It fulfills a need at a lower cost, requires less manufacturing capacity, and involves shorter lead times than an entirely new capability.
The submarine upgrade should be a model going forward. In future capability planning, the US military should treat fielded and in-development capabilities as bases to build from. It should prioritize adaptability and modification-friendliness as a design requirement in new platforms. And it should make building from scratch the exception rather than the default.