“Right after I graduated, I interned with the Arms Control Association. It was terrific.”

– George Stephanopolous
ABC News
January 1, 2005
Modernizing the Triad on a Tight Budget

Amy F. Woolf

In November 2010, as the Senate neared the end of its debate on the New Strategic Arms Reduction Treaty (New START), the Obama administration submitted to Congress an update to its “1251 report,” outlining how it planned to maintain and modernize U.S. strategic nuclear forces under the treaty.[1]

The updated report focused on programs and funding during the next decade, but it confirmed that the United States would invest in facilities, warheads, and delivery systems that would support essentially the same force structure for at least the next 60 years. Although this investment strategy helped win Senate votes for New START, it also has raised questions about the U.S. need for and ability to fund these modernization programs. Deep cuts in the military budget, which the Department of Defense and Congress are considering, could make it difficult for the United States to replace these systems simultaneously. At the same time, the ongoing Pentagon study on how the United States will implement the 2010 “Nuclear Posture Review [NPR] Report” could lead to further reductions in the size of the U.S. nuclear force, mitigating the need for simultaneous modernization programs. However, if the study suggests only modest changes in the planned modernization programs, the pressures of the current budget crisis could lead to greater reductions that might have significant consequences for U.S. nuclear strategy.

The United States deploys its strategic nuclear warheads—those systems limited by New START—on three types of delivery vehicles: long-range, land-based intercontinental ballistic missiles (ICBMs); long-range, submarine-launched ballistic missiles (SLBMs); and long-range heavy bombers based in the United States. Each of the “legs” of this triad is aging, and all may reach the end of their service lives in the next 20 to 25 years.

The U.S. Navy and Air Force plan to pursue programs to modernize and replace each leg of the triad. Yet, as Major General William Chambers, the Air Force assistant chief of staff for strategic deterrence and nuclear integration, has noted, funding for each of these programs will rise sharply later this decade under current plans, creating a “bow wave” of investment in strategic systems.[2] Others have raised similar concerns. In July 2011, shortly before he stepped down as vice chairman of the Joint Chiefs of Staff, General James Cartwright noted that “the challenge here is that we have to recapitalize all three [triad] legs and we don’t have the money to do it.” Later that month, General Robert Kehler, the head of U.S. Strategic Command, raised a similar point when asked whether budget restrictions could affect modernization plans. He noted that “we’re not going to be able to go forward with weapon systems that cost what weapon systems cost today.”

Concerns about the high costs have led to a search for alternatives. Most of these take the form of delaying the current program or reducing the size of the planned force. For example, the Navy has reduced the number of launch tubes planned for each new ballistic missile submarine (SSBN) from 20 to 16. Others have suggested that the Navy also reduce the number of planned submarines, from 12 to 10 or eight.[3] The Air Force has indicated that although it will design the new bomber to deliver nuclear and conventional weapons, it might delay testing of the nuclear capabilities on the new bomber until existing bombers began to retire from the fleet.[4] Others have suggested that the Air Force eliminate bombers from the nuclear force completely and that it delay or even cancel the new ICBM program.

These alternatives could reduce the cost of maintaining and modernizing the U.S. nuclear arsenal, but could also change the future course of U.S. nuclear policy, forcing the United States to alter the roles and missions of its nuclear weapons.

The Current Triad

Each leg of the strategic nuclear triad brought strengths and weaknesses to the U.S. nuclear deterrent during the Cold War. Taken together, the three legs were thought to complicate Soviet attack planning and provide the United States with enough warheads that could survive a Soviet first strike to retaliate with devastating force. Although today’s threats differ from those of the Cold War, the legs of the triad still have complementary capabilities that can contribute to a stable and robust deterrent.

During the Cold War, ICBMs, although vulnerable to a Soviet first strike, had the accuracy and prompt responsiveness needed to attack hardened targets, such as Soviet command posts and nuclear forces. Today, they remain poised to launch promptly, with the accuracy needed to attack the full range of targets. SLBMs, in contrast, could have survived a Soviet first strike, but for many years lacked the accuracy needed to attack the full range of targets as well as the assured communications needed to launch within minutes of an order to do so. With improvements in their guidance and communications, SLBMs may now match ICBMs in these capabilities if they are at sea and within range of their intended targets. Each missile still carries several warheads, however, which may limit the suitability of these missiles for attacks on discrete targets. During the Cold War, heavy bombers could disperse in a crisis to signal U.S. resolve and enhance their survivability, but they would have been slow to reach their targets and were vulnerable to advanced air defenses. These characteristics remain today, but, like ICBMs, heavy bombers can provide the United States with the ability to attack single, discrete targets.

The United States continued to maintain the triad as it reduced its levels of nuclear weapons in the 1990s. The Pentagon cited the deterrent value of the synergy among the three legs, but it also emphasized that this force structure provided a hedge against unexpected problems in any single delivery system. This characteristic grew in importance as the United States reduced redundancy across the force by retiring many of the different types of warheads and missiles it had deployed over the years.

The Obama administration cited both points in support of the triad in the 2010 NPR Report, noting that SSBNs and the missiles they carry “represent the most survivable leg of the U.S. nuclear Triad…. Single-warhead ICBMs contribute to stability, and like SLBMs are not vulnerable to air defenses. Unlike ICBMs and SLBMs, bombers can be visibly deployed forward, as a signal in crisis to strengthen deterrence of potential adversaries and assurance of allies and partners.” The NPR Report also emphasized that the retention of “sufficient force structure in each leg” would allow the United States “the ability to hedge effectively by shifting weight from one Triad leg to another if necessary due to unexpected technological problems or operational vulnerabilities.”[5]

The Obama administration pledged to retain the triad; the limits in New START accommodate this pledge. Yet, there is little analysis to show whether the United States still will need a triad or each leg’s unique capabilities in 15 to 20 years, after New START has expired and the existing systems begin to retire, or over the next 60 years, while the new systems remain in the force.

Minuteman III ICBMs

The Air Force first deployed Minuteman III ICBMs in 1970. It initially deployed up to 550 missiles, with each carrying three warheads. According to the most recent New START data released by the Department of State, the Air Force now deploys 448 Minuteman IIIs in Montana, North Dakota, and Wyoming, with up to 150 missiles per base.[6] It plans to retain up to 420 ICBMs under New START; each of these remaining missiles will carry a single warhead.

The Air Force has recently extended the service lives of the Minuteman IIIs, investing $7.7 billion (in 2010 dollars) between fiscal years 2001 and 2010.[7] The Air Force has poured new fuel into the first and second stages and replaced the third-stage rocket motors of all the missiles. To reduce the life-cycle costs of the ICBMs and maintain their reliability, it is rebuilding and replacing engine components that were produced in the 1970s. It has replaced aging parts in the guidance systems to improve their maintainability and reliability. The Air Force also is upgrading the targeting systems in the Minuteman launch control centers and is deploying newer warheads removed from retired Peacekeeper ICBMs on the Minuteman IIIs.

These programs were supposed to extend the life of the Minuteman IIIs through 2020. In 2006, however, the Air Force decided to continue to modernize the components of the existing missiles rather than to develop and produce new missiles to replace them. This approach could extend the service life of Minuteman IIIs through 2030. The Air Force recently has started to study its options for a missile that could be available after that time and plans to spend $26 million on this study between fiscal years 2012 and 2014. Because it has not yet selected a way forward, however, the Air Force cannot offer any estimate of the eventual cost of a new ICBM program.

If the Air Force acquires a new ICBM, procurement would likely begin in fiscal year 2025 and would overlap with the Navy’s new SSBN program and the Air Force’s new heavy bomber program. As an alternative, the Air Force could delay the acquisition of a new ICBM, while continuing to invest in programs that would sustain and maintain the existing Minuteman IIIs. This alternative could reduce procurement costs for the nuclear triad in the next 10 to 15 years. Yet, it may only delay, not reduce, the long-term cost of a new ICBM. In addition, the Air Force would still have to fund the programs designed to further lengthen the life of the Minuteman IIIs, which would reduce the savings from the delay in the new program. Moreover, even with extensive maintenance programs, the reliability of Minuteman IIIs could degrade over time, possibly forcing their retirement before the eventual acquisition of a new system.

If the Air Force wanted to ensure that it had a new missile available in the 2030 time frame, it could proceed with the program now, but procure perhaps only 200 to 300 ICBMs in the long run. Although this would not reduce the near-term design, research, and development costs, it could reduce procurement costs and the cost to operate and maintain the force over its life. The potential for savings in the cost of operations would depend on how the Air Force deployed the new missiles. If it continued to operate three ICBM bases, as it does today, operating costs would not decline in proportion to the decline in the number of missiles and warheads. If the Air Force deployed the smaller force at fewer bases, it could reduce the costs associated with base operations. With fewer bases and a smaller role for the missiles, however, the Air Force could find it difficult to recruit and retain launch crews and officers with nuclear weapons expertise. The ICBM force could become more of a “niche” capability, and, if SLBMs have the accuracy and responsiveness to take on most of the missions of the land-based leg, the costs of the ICBM force may seem high, relative to the force’s contribution to the country’s nuclear deterrent.

Either alternative could lead to the eventual elimination of the ICBM force, because the Air Force did not invest in a replacement missile or because it invested in the missile but could not convince the Defense Department or Congress to support funding for the acquisition and operations of a smaller force. Without ICBMs, the bomber leg of the triad would increase in value as the only way to attack discrete, single targets, and the SLBM leg would take over as the sole system that could provide a prompt response to threats around the world.

Ohio-Class SSBNs

The Ohio-class (Trident) SSBNs first entered the Navy’s fleet in 1981, with the last of 18 submarines beginning service in 1997. The Navy has converted four submarines to carry cruise missiles, leaving 14 equipped with nuclear-armed ballistic missiles. With two in overhaul, the Navy operates a fleet of 12 submarines; seven are based in Bangor, Washington, and five in Kings Bay, Georgia. The Navy initially planned to keep Trident submarines in service for 30 years, but has extended that time period to 42 years, so the submarines will begin to retire in 2027.

Each Ohio-class submarine has 24 launch tubes for Trident II (D-5) missiles. Under New START, the Navy will eliminate four launch tubes on each submarine, leaving 240 total deployed launchers across the fleet of 12 submarines. The Navy purchased 425 of the original D-5 missiles and is currently buying an additional 108 missiles through a life extension program that will allow the missiles to remain reliable throughout the life of the Trident submarines. The extra missiles, beyond the 240 needed for deployment, support the test program and operational fleet throughout the life cycle of the missiles.

The Navy is designing a new class of SSBNs that would begin to enter service by 2029, as the Ohio-class submarines begin to retire and before the number of operational submarines falls below 12. The Navy would have to begin construction of its new submarine by 2019 to meet this schedule. With an expected 40-year life span, these submarines would remain in the U.S. fleet until 2075. The Navy initially estimated that each new submarine could cost $6 billion to $7 billion in fiscal year 2010 dollars. It has redesigned the submarine to reduce the costs. While the lead ship may cost more than $11 billion, because it will include over $4.5 billion in nonrecurring design and engineering costs, the Navy now expects later ships to average around $5.6 billion per ship. It hopes to reduce that figure to around $4.9 billion per ship. The total procurement cost for the program will reflect the Navy’s success in reducing this average cost. As a result, total estimates vary, ranging from just under $50 billion to nearly $90 billion. As a part of this effort, the Navy is designing the new submarines with only 16 ballistic missile launch tubes. In addition, the Navy will use a new reactor design that will not require a refueling overhaul, allowing the reactor life to match the 40-year life of the submarine.

The Navy says it expects to request a total of $29.4 billion for the new submarine from 2011 to 2020, with $11.6 billion for research and development and $17.8 billion for design and procurement. The total life-cycle costs of the submarine, including research, development, procurement, and operations for a fleet of 12 submarines, will reach nearly $350 billion through 2075.

The Navy could reduce the near-term costs of the new SSBN program if it delayed the start of construction. Although such a delay could mean that several Ohio-class submarines would retire before new submarines entered the fleet, analysts argue that the United States could meet its deterrent requirements with fewer than the current number of 12 operational submarines. They argue that the United States could deploy existing submarines with 24 missiles instead of 20 or existing missiles with eight warheads, rather than three or four, to retain the number of warheads permitted under New START and needed to meet targeting requirements.

The same calculations would support an alternative that started the program now but reduced the number of submarines in the new fleet, with the Navy acquiring only eight or 10 instead of 12. This would not reduce the near-term costs of research and development, but it would reduce the long-term procurement costs for the submarine program and the long-term operating costs of the fleet. A fleet of 12 submarines, with 16 missiles on each submarine and four warheads on each missile, would carry 768 warheads. A smaller fleet of eight submarines could carry 768 warheads if each missile carried six warheads instead of four.

However, the total number of warheads at sea is not the sole measure of the fleet’s capabilities. The Obama administration has stated that the goal for the U.S. submarine fleet is to “maintain continuous at-sea deployments of SSBNs in the Atlantic and Pacific Oceans, as well as the ability to surge additional submarines in crisis.”[8] The current deployment pattern meets this requirement. With five submarines in the Atlantic and seven in the Pacific, the Navy can maintain two submarines on station, patrolling within range of their intended targets, in the Atlantic and three on station in the Pacific. The remainder support the at-sea deterrent, with submarines in port or in transit to their patrol areas. Some of those in transit could surge and reach patrol areas during a crisis.

With fewer submarines in the fleet, the Navy would have to reduce the number of submarines on station, reduce the size of the patrol area, or possibly reduce the fleet to only one base in the Atlantic or the Pacific. Moreover, adding warheads to each missile would reduce the range of the missiles and, when combined with the reduction in the number of submarines on station or the size of the patrol area, could reduce the Navy’s ability to reach critical targets around the world on short notice.

As a result, if the Navy reduced the size of the SSBN fleet, it might not be able to rely on submarines to respond promptly to an unanticipated crisis far from the locations of the forward-deployed forces. Instead, the Navy might have to delay its response and rely on its ability to change its patrol areas or increase its patrol rates by surging during a crisis. This could leave the ICBM force as the sole system that could provide a prompt response to threats around the world.

Heavy Bombers

The Air Force currently has 20 B-2 bombers, with 16 “combat coded” for nuclear missions, at Whiteman Air Force Base in Missouri. The B-2 first entered service in 1997; the Air Force expects it to remain active until 2034 or later. The Air Force invested $5.1 billion in life extension programs for the B-2 fleet between fiscal years 2001 and 2010 (in fiscal year 2010 dollars) and plans to spend an additional $3.5 billion between fiscal years 2011 and 2016.

The B-2 can carry B61 and B83 nuclear bombs as well as conventional weapons and has participated in U.S. military campaigns from Bosnia to Iraq. The B61-10 bomb can penetrate some hardened targets. The B83 bomb is a high-yield weapon that is also designed to destroy hardened targets, such as ICBM silos. The B-2 also can carry the B61-Mod 7, which may be modified as a part of the planned life extension program to enhance the safety, security, and use control features on B61s.

The Air Force maintains 76 B-52H aircraft in the active inventory, although only 44 are “combat coded” for nuclear missions. These are located at Barksdale Air Force Base in Louisiana and Minot Air Force Base in North Dakota. The B-52 first entered service in 1961 and is expected to remain in the fleet through 2040. It has undergone many modernization and life extension programs over the years. The Air Force allocated $1.4 billion to these programs between fiscal years 2001 and 2010 and expects to request an additional $1.3 billion between fiscal years 2011 and 2016.

The B-52 can carry nuclear or conventional cruise missiles and several other conventional weapons. The Air Force plans to begin a life extension program for its nuclear-armed air-launched cruise missiles (ALCMs) in fiscal years 2012 and 2013 and to sustain the ALCMs through 2030. The Air Force has begun a study on a new advanced long-range standoff cruise missile that will replace the ALCMs after 2030. This missile, which may eventually cost $1.3 billion, may begin initial production around 2025.

The Air Force also plans to develop a new bomber. This aircraft is needed for conventional long-range strike missions, although the plane would be able to deliver nuclear weapons. In October 2011, Air Force Chief of Staff General Norton Schwartz indicated that the new bomber probably would not have nuclear capabilities initially but that they would be added later as the B-2s and B-52s retired from the fleet. The Air Force plans to procure 80 to 100 new bombers, with the first expected to enter service around 2025, at an estimated procurement cost of $550 million for each bomber.

Because the B-2s and B-52s may remain in the fleet through 2040, the Air Force could delay the acquisition of a new bomber to reduce the near-term costs of this program. As with the ICBM program, a delay in the program would not necessarily reduce its long-term life-cycle costs. In addition, because the Air Force plans to acquire the bombers as part of its conventional long-range strike mission, a delay could undermine the broader program and interfere with the requirements for conventional capabilities. The Air Force could reduce the size of the program, buying fewer than the planned 80 to 100 aircraft, which would reduce the eventual procurement and operating costs for the bomber fleet but could also undermine the Air Force’s ability to meet its conventional-weapon mission requirements in future conflicts. The Air Force might also delay or restructure the life extension and replacement programs for the weapons carried on the bombers, although the bombers would not be a part of the nuclear mission if these weapons are not available.

Finally, the Air Force could, as seems likely, delay introducing the nuclear capability onto the new, long-range strike aircraft by delaying the development and testing of software and other equipment needed for the nuclear mission. This would reduce the training and operating costs for the bomber for a period of time. Yet, if budget constraints eventually limit the size of the bomber program and if the conventional mission remains paramount, it is possible that the Air Force may never introduce nuclear capabilities onto the new bomber.

As a result, efforts to reduce the cost of the bomber modernization program by delaying the bomber or the weapons could eventually result in the removal of the bombers from the nuclear mission. This would eliminate the U.S. ability to signal resolve in a conflict by dispersing nuclear-armed bombers and leave the ICBM fleet as the sole means for the United States to attack individual, discrete targets.

Consequences for the Force

If the Navy and Air Force individually decided to delay or cut back their modernization programs, the United States could end up with a strategic nuclear force deployed mostly at sea and limited to a delayed response after an attack from another country. Without nuclear weapons-capable bombers, the Air Force would lose an ability to signal intent by dispersing the aircraft in a nuclear crisis. Although a small ICBM force would allow the United States to retain its ability to launch prompt, discrete attacks against critical targets, this force could prove to be too costly, and the Air Force might give up that mission as well. With fewer submarines at sea, the Navy could not maintain the current SSBN operating patterns, leaving it more reliant on its ability to relocate its forces during a crisis.

A strategic force with fewer submarines and little or no ICBM and bomber capability could limit the United States’ ability to draw on the unique characteristics and synergy of the current nuclear triad. Many have argued, however, that the current size, shape, and operating patterns of the triad reflect Cold War requirements and an outdated role for nuclear weapons.[9] The United States could adopt a posture that is designed more for minimum deterrence than war-fighting—one that seeks to deter attack by maintaining the ability to retaliate only after a nuclear attack by an adversary.

However, the Obama administration indicated in the 2010 NPR Report that the synergy and redundancy of the three legs of the triad were still important, that the United States was not ready to move to a “sole purpose” doctrine for its nuclear weapons, and that the country still required capabilities that allowed for a nuclear response in a wider range of contingencies. The Defense Department’s ongoing NPR implementation study could alter this conclusion and determine that the U.S. deterrent would remain robust with a nuclear force that did not include as large an ICBM force, as many SSBNs on station, or any nuclear capability on bombers. On the other hand, the study could recommend modest changes in the U.S. force structure, but conclude, as did the original NPR, that the United States should retain the existing triad with essentially the same operational capabilities but possibly at somewhat reduced numbers.

Regardless of the outcome of this study, its recommendations are likely to reflect a consideration of potential threats and U.S. nuclear requirements only over the next 10 to 15 years. In contrast, the modernization programs described in this article will provide forces for the next 60 to 70 years. Although it may be too difficult for the Pentagon to assess the security environment that far into the future, it also is not possible for the Pentagon or anyone else to be sure that the United States will need a prompt retaliatory capability, with several submarines on station in two oceans and discrete attack options from land-based and air-delivered weapons, that far into the future. In the absence of such a long-term analysis, it may be prudent to plan to retain the current force structure by beginning the modernization programs now, while holding open the option of later reductions in the size of the programs and the resulting force structure. In other words, current threats and current strategy would make the current force structure appropriate, while future changes in threats and strategy may allow changes in it.

This will do little to address the current budget pressures. If the NPR implementation study does not recommend significant changes in the size and structure of the U.S. nuclear arsenal, budget cuts that delay or scale back the modernization programs could force the same result. Indeed, these budget-driven changes in nuclear strategy and operations could be more extensive than those recommended by the Pentagon study. ACT


Amy F. Woolf is a specialist in nuclear weapons policy at the Congressional Research Service. The views expressed in this article are her own and do not reflect the views of the Congressional Research Service or the Library of Congress.





1. Congress requested the report in the fiscal year 2010 National Defense Authorization Act (section 1251). For the text of the November 2010 update to the May 2010 report, see www.lasg.org/CMRR/Sect1251_update_17Nov2010.pdf (hereinafter Section 1251 Report update).

2. “Chambers: ‘Bow Wave’ of Nuclear Triad Costs Coming After FY-17,” Inside the Air Force, October 28, 2011.

3. See Michael O’Hanlon, “To Save Money, Look to Nukes,” The Los Angeles Times, November 16, 2011.

4. Jen DiMascio, “Air Force Looks to Contain Bomber Costs,” Aviation Week and Space Technology, November 2, 2011.

5. U.S. Department of Defense, “Nuclear Posture Review Report,” April 8, 2010, pp. 21-22, www.defense.gov/npr/docs/2010%20Nuclear%20Posture%20Review%20Report.pdf.

6. Bureau of Arms Control, Verification and Compliance, U.S. State Department, “New START Treaty Aggregate Numbers of Strategic Offensive Arms,” October 25, 2011, www.state.gov/t/avc/rls/176096.htm.

7. The Air Force may request an additional $2.3 billion for research, development, and procurement on Minuteman sustainment programs through fiscal year 2016.

8. See Section 1251 Report update.

9. Kingston Reif, “What the Super Committee’s Failure Means for Nuclear Weapons,” Bulletin of the Atomic Scientists, December 14, 2011.