WASHINGTON ― The Nuclear Posture Review, formally unveiled Friday, recommends adding a low-yield warhead for submarine-launched ballistic missiles, as well as the addition of a nuclear-capable submarine-launched cruise missile to America’s arsenal.
The question now becomes when these capabilities will come online ― and how much they will cost at a time when the Pentagon is restrained by congressionally mandated budget caps.
Before the addition of these new capabilities, the U.S. was preparing to spend $1.2 trillion over the next 30 years to modernize the nuclear arsenal, including the delivery systems, warhead, and command and control network. And the now-retired head of the National Nuclear Security Administration told Defense News weeks ago that his agency is “at capacity” with the work it has already been assigned to do.
Robert Soofer, deputy assistant secretary of defense for nuclear and missile defense policy, said the question of logistics and funding was “squarely in our thinking” when looking at the new capabilities. But Greg Weaver, deputy director for strategic stability on the Joint Staff J5, said the reality is that details for acquiring the new systems still need to be worked out.
“The NPR doesn’t get into system engineering, so the department has a very well-laid out process for identifying the specific operational military requirements for additional capabilities,” Weaver said. “We don’t know what that would cost because we don’t know how we’re going to do it yet. Specifically you can’t cost it out until you know the approach you’re taking technically and the cost of operations, etc. And that’s all going to go through our normal process. “
Here’s what we know about the two new systems:
Low-yield warhead for sub-launched ballistic missile
The NPR calls for a “near-term” solution, in which the National Nuclear Security Administration would modify a small number of existing submarine-launched ballistic missile (SLBM) warheads to turn them into low-yield weapons. The agency is already in the process of doing a life-extension on the W76 warheads for those weapons, something Soofer noted should help keep the cost and schedule down.
“All this would require us to reserve the last X number, tens of warheads, and instead of doing a full [life extension], do the primary only. It doesn’t require additional capacity,” Soofer said of developing the capability. On the Navy side, the service would “just take that warhead and make sure they can qualify” and SLBM on a sub.
By “low-yield,” Soofer said he means smaller than the weapon detonated at Hiroshima, which instantly vaporized an estimated 60,000-80,000 people.
While noting it was a rough guess on cost, Soofer said he thought the Defense Department’s portion of the cost would perhaps be $50 million over five years. The question then becomes one of how many low-yield warheads would be desired, and Soofer stressed that the number they are envisioning is quite low.
“This is, again, a very limited, niche capability,” he said. “This is not a major war-fighting capability. If we’re talking about firing tens of these, you’re in a different realm. The idea is to have one or two or just a few to address” the potential threat from Russia.
But the idea of mixing strategic and tactical nuclear warheads on one ballistic missile submarine creates the potential for a “discrimination problem,” said Vipin Narang, an associate professor of political science at the Massachusetts Institute of Technology who focuses on nuclear proliferation.
“Very simply, how is an adversary supposed to know if the [ballistic] missile headed its way has a single low-yield nuclear weapon or a full complement of eight 475-kiloton strategic nuclear warheads? These things are not color-coded,” he said. “They would have no way of being able to detect or discriminate what was on even a single SLBM launch, let alone several.”
“Even if we were using just a single low-yield warhead on a single SLBM, the adversary literally cannot know that and has to assume we have escalated to the strategic level,” Narang added. “Especially if that adversary worries about the survivability of its own forces, its only rational move is to launch everything it has.”
Submarine-launched, nuclear-capable cruise missile
The NPR calls for a new sea-launched cruise missile, something the Navy had in its inventory until just a few years ago. The review orders an analysis of alternatives to look at the options, though Soofter noted this weapon will be “more labor- and cost-intensive” than the ballistic missile warhead.
The NPR calls for the design to leverage existing capabilities to keep cost and schedule down. Soofer jumped on that idea, noting the Air Force is in the process of designing its new nuclear cruise missile, the Long Range Standoff Weapon, or LRSO, and speculating that provides a base with which to work.
‘“We’re already doing a warhead for the Long Range Standoff Weapon. It’s going to be a version of the W80 warhead. So you [could potentially] just increase that production run and do more of those and put them into this new sea-launched cruise missile,” Soofer said. “Maybe the LRSO is actually the airframe and you can adjust that for cruise missile surface ship launch, maybe you can do some version of the Tomahawk.”
Part of the analysis will look at whether the weapons could be placed on surface ships, submarines or both, Soofer added, before noting: “This thing is seven to 10 years out.”
Notably, Weaver broached the idea that the SLCM could be used as a carrot to Russia to move back underneath the Intermediate-Range Nuclear Forces Treaty.
“Were Russia to agree to return to verifiable arms control measures to address that imbalance in nonstrategic nuclear forces, the U.S. might agree to limit or forgo [acquiring] a nuclear SLCM,” he said. “This is a response to Russian expansion of their capability and the nature of their strategy and doctrine. The United States is not arms racing. We are responding to Russian initiative.”
Aaron Mehta was deputy editor and senior Pentagon correspondent for Defense News, covering policy, strategy and acquisition at the highest levels of the Defense Department and its international partners.