Because of the high—potentially budget-busting—costs of the Ohio (SSBN-726) replacement program, alternatives to U.S. sea-based strategic forces have been proposed in several quarters. Beyond further efforts to reduce the costs of the new nuclear-powered ballistic-missile submarine, the most-voiced suggestions have been to (1) build fewer Ohio replacement submarines and (2) build an SSBN based on the Virginia design.
A smaller number than 12 of the new SSBNs—which will carry fewer missiles than the boats they replace—might be too great a risk given the prospect of future antisubmarine systems. The Ohio replacement program accepts a one-third reduction of missile tubes (16 instead of 24) while the same number of missile submarines would be at sea as today. As noted in the last issue (Part One), because the Ohio replacement submarines will not have to be taken out of service for midlife nuclear refuelings, the 12 new SSBNs could keep the same number of boats at sea as the current force of 14 Ohio-class SSBNs. Still, an objective, non-Navy analysis by qualified specialists should be undertaken to justify the numbers of submarines and missiles that the United States should put to sea.
The second alternative being proposed is to build a new SSBN based on the Virginia-class attack submarines, i.e., add ballistic-missile tubes, a fire-control system, and other features. This approach was undertaken in the 1950s when the Skipjack (SSN-585) attack submarine design was lengthened and provided with 16 Polaris missile tubes and related equipment to produce the U.S. Navy’s first ballistic missile submarine, the USS George Washington (SSBN-598). (“Urban myth” has it that a Skipjack-class submarine on the building ways was cut in half and the missile section inserted to produce the George Washington; the only thing that was cut in half were the plans—construction of the submarine had barely begun.) An SSBN design based on the Virginia hull probably would require more than 12 boats to meet operational requirements, require midlife refueling, and increase personnel costs.
However, another aspect of the Virginia SSN design could be considered for the strategic-missile role. The next block of Virginia-class submarines will be lengthened approximately 70 feet to accommodate the Virginia payload module (VPM), an inserted section containing four 87-inch-diameter tubes.1 Each of these four tubes can accommodate seven Tomahawk land-attack missiles (TLAMs) or, in the future, a smaller number of larger missiles. In addition, the Virginia-class submarines have 12 TLAM launch cells fitted in their bow section. Thus, these Block V submarines with VPM will each be able to carry 40 TLAMs. This VPM/Tomahawk concept evolved from the submarine community’s desire to have replacements for the four early Ohio-class submarines that were converted to cruise-missile platforms (SSGN). Those four submarines—SSGN-726 through 729—are planned for retirement about 2026–2028.
Further, if the Virginia/VPM concept is successful, the Navy’s next-generation attack submarine—for which early preparation design work is starting—could be optimized to carry TLAMs.2 Or perhaps two next-generation submarine variants could be produced: one primarily for the SSN role and one primarily for the SSGN role. (The Navy’s current long-range plans, always tenuous at best, call for the first post-Virginia SSN to be authorized in 2034 and to become operational in 2044.)
The Tomahawk conventional land-attack missile that is carried by most U.S. attack submarines as well as the four Ohio-class SSGNs and all cruisers and destroyers, originally was developed as a strategic attack weapon with a nuclear warhead. Its origins are traced to development of the Williams turbofan engine and the early 1970s decision by then–Chief of Naval Operations Admiral Elmo R. Zumwalt to make cruise missiles a high priority, albeit primarily for the antiship role. The Tomahawk initially was known as the sea? or ship-launched cruise missile (SLCM). Zumwalt, a surface warfare officer, demanded that the cruise missiles being developed have a diameter of no greater than 21 inches to permit their firing from submarine torpedo tubes. (This applied to the antiship Harpoon missile as well as the SLCM series.)
By the mid-1970s the SLCM was viewed as primarily a strategic attack missile, with 375 missiles at sea on 25 surface warships being proposed by the Nixon administration as a balance in strategic-arms negotiations to 300 Soviet Tu-22M Backfire bombers.3 The CNO at the time, Admiral James L. Holloway III, an aviator, opposed the SLCM program.4 He believed that aircraft carriers—which then embarked nuclear strike aircraft—could provide the necessary sea-based strategic attack capabilities.
The administration prevailed with the Navy-developed BGM?109A land-attack missile with the W80 nuclear warhead, although deployment was delayed by U.S.-Soviet arms negotiations. The first Tomahawk to go to sea was the antiship variant, in surface ships, in 1982. The nuclear TLAM went to sea in 1987. At the same time, a land-launched nuclear Tomahawk was developed and (briefly) deployed in Western Europe, the Gryphon BGM-109G. Thus TLAM/nuclear technology is readily available, and research-and-development costs would be minimal. Supersonic cruise missiles that could fit the Tomahawk “envelope” are in the offing.
Is there a case for a mix of sea-based strategic weapons—Trident D-5 ballistic missiles and TLAM/nuclear cruise missiles? The now-discarded TLAM/nuclear had a range of some 1,000 miles and a warhead of 5 to 150 kilotons.5 While that was a comparatively small warhead, the inertial and terrain-following guidance provided remarkable accuracy.
While the Tomahawk has a considerably shorter range than the Trident missile, Virginia/VPM submarines could easily operate in the Mediterranean, Indian Ocean, Western Pacific, and Arctic, bringing them within range of many potential strategic targets. Further, because it would be virtually impossible to distinguish these TLAM submarines from “straight” attack submarines, they would blend in with the 40 to 50 SSNs in the Fleet, and would not present the signatures—both acoustic and non-acoustic—of the significantly larger, special-configuration Ohio-replacement submarines. While some would argue that such submarines with nuclear cruise missiles could confound strategic arms talks, it should be recalled that in previous agreements there were provisions for differentiating between nuclear-armed and non-nuclear-armed B-52 Stratofortress bombers.
Thus, as a possible cost-cutting measure (i.e., constructing 8 or 10 SSBNs and not 12), and as a means of confusing a potential enemy’s defenses—both antisubmarine and ballistic missile—the mix of sea-based ballistic and cruise missiles seems to warrant serious analysis and consideration. (In the past the United States had sought a mix of sea-based strategic weapons—carrier-based nuclear-strike aircraft as well as missile submarines, the Regulus II strategic cruise missile as well as Polaris ballistic missiles, and Tomahawk/nuclear cruise missiles as well as Poseidon/Trident ballistic missiles.)
Decisions and program starts must be made in the near term because the Ohio-class submarines are wearing out and other, follow-on strategic programs are in the offing: the Air Force next-generation bomber, a replacement for the Trident D-5 missile in the 2040s, and a successor to the land-based Minuteman intercontinental ballistic missile. The Ohio-class replacement program must be initiated, hopefully incorporating the best acoustic and non-acoustic quieting features now available. The final number of submarines should be addressed in the context of an objective analysis of numbers and the potential for a cruise-missile component.
The sea-based strategic missile force is vital to U.S. interests. However, cost considerations are a major factor in all weapon-procurement decisions. Submarine-launched ballistic missiles and cruise missiles could be the way to provide the most survivable and, in many respects, most effective U.S. nuclear force—at an affordable cost.
1. See Ronald O’Rourke, Navy Virginia (SSN-74) Class Attack Submarine Procurement: Background and Issues for Congress (Washington, DC: Congressional Research Service, 31 July 2014), 5–6.
2. RADM Dave Johnson, USN, presentation to Naval Submarine League, Falls Church, VA, 23 October 2014.
3. Henry Kissinger, Years of Renewal (New York: Simon & Schuster, 1999), 856–58.
4. Ibid., 857.
5. The last TLAM nuclear warheads were dismantled in 2012.