This option would more cost-effectively deploy 1,550 New START-accountable warheads by reducing the size of the triad to 10 SSBNs and 300 ICBMs ($40 billion in savings), delaying the GBSD program in favor of extending the life of the Minuteman III and reducing the number of ICBMs ($17.5 billion in savings), eliminating the LRSO ($30 billion in savings), no longer deploying B61 gravity bombs in Europe ($17 billion in savings), pursuing simpler warhead life extension programs ($10 billion in savings), and developing a capability to produce 30 plutonium pits per year ($6 billion in savings) (See figure below). This option would save $120.5 billion relative to the CBO baseline and $149.3 billion when combined with eliminating the Trump additions. Additional savings could be achieved by reducing the triad to eight SSBNs and 150 ICBMs and delaying the B-21 program or purchasing fewer B-21s.
Reduce triad to 10 SSBNs
and 300 ICBMs
Delay GBSD program
Don’t deploy B61 gravity
bombs in Europe
Pursuing simpler warhead
Reduce to 30 pits/year
Eliminate Trump additions
Savings of $149.3 billion would cover nearly the entire additional acquisition cost over the next 30 years relative to current plans to grow the Navy to 355 ships by the late 2030s (estimated by the CBO at $161 billion)142.
Under this option the United States in 2030 would deploy roughly 1,550 New START accountable warheads on 520 strategic delivery systems consisting of 200 SLBMs, 300 ICBMs, and at least 20 nuclear-capable bombers. To achieve this level of warheads with a smaller number of delivery systems, the Navy would deploy an average of six warheads on each SLBM instead of the current loading of four-to-five warheads. By 2046 the United States would deploy about 1,450 warheads on 160 SLBMs, 300 ICBMs, and 100 nuclear-capable bombers. Each SLBM would carry six-to-seven warheads. By 2046 the current fleet of Ohio-class submarines armed with 20 operational SLBM tubes under New START will be replaced by the Columbia-class boats armed with 16 SLBM tubes. In addition, the current fleet of about 40 nuclear-capable B-52 bombers would be removed from the nuclear mission due to the elimination of ALCMs and replaced by a fleet of at least 100 B-21 bombers, some or all of which will be nuclear-capable. The Air Force plans to begin retiring the B-2 bomber in the late 2030s143.
Reducing the triad to eight SSBNs and 150 ICBMs and the number of deployed warheads to 1,000 would save an additional $45 billion through fiscal year 2046, according to the CBO.
Reducing the Number of Submarines
The Navy is planning to purchase 12 new Columbia-class submarines to meet current military requirements but shifting to 10 strategic submarines would still provide a devastating sea-based nuclear deterrent. The CBO projects that purchasing two fewer new boats would save $17 billion through fiscal year 2046. The majority of the savings from reducing to 10 submarines would come during the early 2030s when the last two Columbia-class submarines are scheduled to be purchased. These savings would lessen the burden on the Navy’s shipbuilding budget as it seeks to expand the fleet to roughly 350 ships.
The Navy is seeking 12 new boats rather than 14 because the new submarine will not need a four-year mid-life refueling, but only a two-year overhaul.144 The Navy originally planned to start deploying the replacement boats in 2029, but in 2012 the Pentagon announced a two-year delay to the program, pushing back the fielding of the first new submarine to 2031. As a result, the Navy will field only 10 ballistic missile submarines in the 2030s. Under New START the Navy plans to deploy about 1,000 warheads on 240 SLBMs.
Current military requirements call for 10 strategic submarines to be operational at all times to ensure that five submarines are “on station” within range of their targets so SLBMs can be launched promptly, as quickly as within 15 minutes of an order to do so. For the Navy to operate five submarines on station, it would need 12 submarines in total: five in the Atlantic, with two on station and the rest in transit or in port (such as for maintenance), and seven in the Pacific with three on station and the rest in rotation. Initially, only 10 submarines are needed to meet these goals.145
The need for 12 submarines, then, has as much to do with where the warheads are deployed and how promptly they could reach their targets as it does with the number of warheads. A fleet of 10 Columbia-class submarines can carry nearly 1,300 warheads, but it cannot support five submarines that are deployed close enough to their targets in Russia and China, ready for quick launch. In addition, reducing the number of submarines to 10 and increasing the number of warheads per SLBM would reduce, though not eliminate, the Navy’s flexibility to deploy SLBMs with one or two warheads and to upload nondeployed warheads in the event of a need to significantly increase the deployed arsenal. Reducing to eight boats would further reduce that flexibility. Increasing the number of warheads per SLBM could also reduce the range of the missile.
However, relaxing the requirements for prompt launch, especially against counterforce targets, would allow fewer than five submarines to be on station, thereby eliminating the need for 12 new submarines. So too would reducing the required number of deployed warheads. With a smaller arsenal, the United States also would not need such a large upload capability. Carrying extra spaces on SLBMs for warheads is an expensive hedge.
Refurbishing the Minuteman III and Reducing Their Number
The ICBM leg of the triad is the least valuable leg of the triad and plans to sustain it should reflect this reality. Due to a limited range of flight trajectories, the Minuteman III is essentially unusable outside of a nuclear conflict with Russia. The Trident D-5 SLBM is mobile, highly accurate, and capable of prompt launch. In addition, continuing to maintain ICBMs in a “launch under attack” mode is unnecessary and risky. The primary mission of the land-based leg of the triad is to deter an adversary nuclear first strike attack and serve as a backstop to an unforeseen and unlikely future vulnerability in the SLBM force. But these functions can continue to be performed at lower numbers of ICBMs and by deferring the development of a new ICBM.
The CBO projects that $17.5 billion could be saved over the next 30 years by delaying development of a new ICBM by 20 years and instead extending the life of the Minuteman III by buying new engines and new guidance systems for the missiles. Crucially, however, this approach would save $37 billion through fiscal year 2036 when the vast majority of nuclear recapitalization spending is scheduled to take place. The Air Force has to contend with the high cost of several other priorities during this period in addition to GBSD, including the F-35, B-21, and new tanker programs.
The U.S. Air Force currently deploys about 400 single warhead Minuteman III ICBMs located at F.E. Warren Air Force Base, Wyoming; Malmstrom Air Force Base, Montana; and Minot Air Force Base, North Dakota. Under New START, the Air Force maintains 50 extra missile silos in a “warm” reserve status. The Minuteman III was designed in the 1960s and entered service throughout the 1960s and 1970s. Today’s Minuteman weapon system is the product of almost 40 years of continuous enhancement. The Pentagon spent over $7 billion in the early 2000s to keep the ICBMs safe, secure and reliable through 2030146. This modernization program has resulted in an essentially “new” missile, expanded targeting options, and improved accuracy and survivability147.
To reduce the number of ICBMs from 400 to 300, the Air Force would have several options. It could remove 100 missiles from the deployed force and distribute the reductions across the three bases while leaving the silos in a warm status. It could also eliminate a wing of 50 silos from two of the three bases. Yet another option would be to eliminate an entire base of 150 silos, which would save roughly $200 million per year148.
The Defense Department is planning to replace the Minuteman III missile, its supporting launch control facilities, and command-and-control infrastructure. The plan is to purchase 666 new missiles, 400 of which would be operationally deployed through 2070149. The remaining missiles would be used for test flights and as spares. The Pentagon is seeking to make significant capability upgrades as part of the recapitalization program, known as the GBSD. According to the 2018 NPR, the life of the Minuteman III “cannot be extended further” and the missiles “will have increasing difficulty penetrating future adversary defenses.”
The Air Force initially estimated the cost of the GBSD program at $62 billion in then-year dollars. But the Pentagon in August 2016 set the estimated acquisition cost of the program at $85 billion and the total life-cycle cost at $238 billion in then-year dollars. The $85 billion estimate is at the lower end of an independent Pentagon cost estimate that put the acquisition price tag as high as $150 billion.150 Many ICBM proponents argue that they are the cheapest leg of the triad to maintain and modernize, but the independent estimate of approximately $150 billion exceeds the projected cost of $128 billion for the Columbia-class submarine program.
The Air Force in 2014 conducted an analysis of alternatives to sustain the ICBM leg of the triad which showed that the price to build a new missile system would be roughly the same as the cost to maintain the Minuteman III151. However, the service arrived at this conclusion by comparing the total lifecycle cost of each option through 2075. This meant that the Minuteman III life extension option included the costs of both refurbishing the existing missiles and the costs of building a new fleet of replacement missiles. The analysis of alternatives also assumed a need to deploy 450 missiles.
In contrast, the CBO evaluated the cost of the two options over a shorter period of time. In addition, a 2014 report by the RAND Corporation on the future of the ICBM force found that “any new ICBM alternative will very likely cost almost two times—and perhaps even three times—more than incremental modernization of the current Minuteman III system.”152 The report said continuing to maintain the Minuteman III through life-extension programs and “gradual upgrades is a relatively inexpensive way to retain current ICBM capabilities.”
The RAND study identified two challenges to this approach. First, the number of Minuteman III missile bodies is declining due to test launches. Based on the current testing pace of roughly 4–5 tests per year, maintaining a force of 400 missiles, as is the plan under New START, would deplete the test inventory by 2035. Second, the report said incremental modernization would be “viable” only if the capability the Minuteman III provides “is not substantially changed.”
But reducing the number of ICBMs to 300 and forgoing capability upgrades, which are unnecessary for the ICBM force to continue to serve its sponge function, would mitigate these challenges. Life-extended Minuteman III missiles can get blown up in their silos by incoming Russian ICBMs less expensively than new GBSD missiles. Moreover, the claim that the Minuteman III may not be able to overcome expected advances in adversary air and missile defenses over the next two decades merits further scrutiny given the repertoire of countermeasures the missile is already believed to contain to overcome such defenses.
Some analysts argue that refurbishment is not viable due to the aging-out of the Minuteman III’s component parts153. Extending the life of the Minuteman III could entail some technical risk. However, neither RAND nor the 2014 analysis of alternatives determined that doing so is infeasible.
Additional savings could potentially be found from keeping Minuteman III missiles past their anticipated expiration in the early 2030s, which would delay, if not obviate, the need to refurbish the missiles. For example, Todd Harrison, the director of the Aerospace Security Project at the Center for Strategic and International Studies, wrote in a 2017 report that keeping the missiles three years longer than planned, would increase the probably of failure at launch from 1.3 to 3.8 percent.154 But as Harrison notes:
“If the primary purpose of the ICBM force is to deter an attack by acting as a missile sponge, then quantity is arguably more important than reliability. At extremely high levels of unreliability, an adversary could begin to disregard the missiles altogether. At the range of failure rates discussed here (up to 3.8 percent), though, that adversary would still need to target all of the ICBMs to neutralize them.”
The Defense Department continues to use even older Minuteman II rocket motors for military space launches, which suggests the department has high confidence in the boosters. Which begs the question: If older Minuteman II motors are still functioning reliably, could the newer Minuteman III boosters reliably last longer than currently planned?155
The Air Force has yet to demonstrate that sustaining the Minuteman III beyond the missiles’ expected retirement in the 2030 timeframe is not a viable or more cost-effective nearer-term option. Former undersecretary of defense for policy Michèle Flournoy stated in 2017 that “the Defense Department should more seriously consider further extending the life of the existing Minuteman III ICBMs as a cheaper near-term alternative to the current plan to build an entirely new ICBM system.”156 Pursuing this approach would carry significant option value as it would defer a decision on whether to build an entirely new system.
Additional Savings from this Option
Eliminating the LRSO and no longer deploying B61 gravity bombs in Europe would save $47 billion through fiscal year 2046. As noted above, these weapons are militarily unnecessary and in the case of the LRSO pose underappreciated risks to stability. Under this option removing tactical nuclear weapons from Europe would not alter the scope of the B61-12 life extension program but would result in foregoing plans to make the F-35 nuclear-capable.
Jettisoning the LRSO and F-35 nuclear capability would leave B61-12s delivered by the B-2 and later the B-21 as the lone low-yield option in the U.S. nuclear arsenal. Given the enormous investment that is being made in the B-21, there should be no doubt about the bomber’s ability to penetrate even the most advanced adversary air defenses for the foreseeable future. If a second low-yield option is required, then fielding the low-yield SLBM as proposed by the Trump NPR would be a far more cost-effective option, though the risks to stability and the survivability of SSBNs highlighted earlier in this report would still remain.
Building a capability to develop 30 plutonium pits per year instead of 80 and ditching plans to build interoperable warheads would save $14.5 billion through 2046. The estimated $6 billion in fiscal year 2018 dollars in savings from building only 30 plutonium pits, which is based on forgoing the least expensive option studied by NNSA to build an additional 50 pits, is likely an underestimate given that the cost to build the necessary infrastructure to produce the extra pits is at the low end of NNSA’s projected cost range for the option.
As described earlier, the United States does not need to build at least 80 pits per year. Achieving the capability to build even 30 by 2030 would be an enormous achievement given that the Energy Department has not produced pits at such a quantity since the 1980s and had to cease major plutonium operations at Los Alamos’ Plutonium Facility-4 from 2013-2017 due nuclear criticality safety concerns. Once NNSA demonstrates a capability to manufacture 30 pits per year, it can re-evaluate the need for additional pits based on the anticipated aging of existing pits, the size of the total warhead stockpile, and the international security environment.
The need for increased pit production could also be reduced by pursuing less ambitious warhead life extension programs. The model for future life extensions should instead be the Navy’s simpler, $4 billion in then-year dollars W76 SLBM warhead life extension program.157 In addition, instead of rebuilding the W78 warhead, it should be retired. A smaller ICBM force means there is no need to keep two different ICBM warheads. The W87 is newer and has modern safety features. Enough W87 warheads have been produced (more than 500) to arm the entire ICBM fleet. The estimated savings of $10 billion in this option from forgoing the development of interoperable warheads assumes a simpler life extension program for the W78 warhead, not its retirement.
Delaying the B-21 bomber program or purchasing fewer B-21s would result in additional savings. According to the CBO, deferring development of the B-21 would save $34.5 billion through fiscal year 2046. The CBO projects the cost of each B-21 at $690 billion. Reducing the planned buy from 100 to 70 bombers could thus save $20.7 billion, though the actual savings might be less than that amount due to the loss of economies of scale.
The primary mission of the B-21 is to allow the Air Force to continue to provide a conventional long-range penetrating bomber. The B-21 would not be certified to carry nuclear weapons until two years after it is first deployed. According to the Pentagon, only about five percent of the bombers’ acquisition cost would go directly to making the bombers capable of carrying nuclear weapons158. However, if the bomber did not have a nuclear mission, the overall program could be less expensive. For example, the bombers might not need to use pilots, but could be operated remotely.
Even with a 10-year delay, a new bomber would still be ready by about the time current bombers are reaching the end of their service life and the delay would allow the new bomber to incorporate technological advances made during that time. “Taking advantage of future technological developments can be particularly valuable for weapon systems that are expected to be in use for several decades,” the CBO states159. In addition, by moving B-21 funding into the future, the Air Force would free up resources for other priorities, such as buying KC46A tankers and F-35A fighters. Buying fewer bombers would also save money for the “Penetrating Counter Air” aircraft the Air Force is seeking to replace the F-22 and part of the F-15 fleet beginning in 2030.160
The B-2, the last U.S. bomber built, provides a cautionary tale. In the 1980s, plans called for 132 B-2s, and then 75, but the dissolution of the Soviet Union led to growing congressional opposition. In 1992, President George H.W. Bush announced that production would be limited to 20 aircraft. Twenty-one B-2s were ultimately built, at a cost of more than $2 billion each, far above initial estimates. Its predecessor, the B-1, also was never built in the numbers envisioned.161
However, delaying fielding of the B-21 until the late 2030s would limit the Air Force’s inventory of stealthy bombers able to fly in defended airspace to the 20 B-2s in today’s bomber force. While this disadvantage would be less pronounced if the B-21 only had a nuclear mission, the main purpose of the bomber is conventional. Delaying the bomber might also weaken the rationale for forgoing the LRSO in favor of the B61-12.