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Future Navy Submarine to Stick With Nuclear Mission
WASHINGTON -- The U.S. Navy will focus the mission of its future strategic submarine solely on nuclear deterrence, and -- at least initially -- the vessel will carry the same type of ballistic missile as fielded today, a senior officer said last month (see GSN, April 30).
Defense leaders had earlier said that new submarines in the fleet -- which are to begin replacing the service's 14 Ohio-class "SSBN" boats in 2029 -- could carry both nuclear- and conventionally armed missiles (see GSN, April 24, 2008 and Sept. 18, 2007).
However, in recent weeks, military leaders have significantly trimmed back their plans, citing both congressional concerns and financial constraints.
"Right now the mission of the Ohio replacement program is nuclear strategic deterrence," Rear Adm. Terry Benedict, director of the Navy Strategic Systems Planning office, said at a July 22 breakfast event on Capitol Hill. "We've made that clear in our discussions with both the House and the Senate. And we understand that very clearly, the direction that this is a single-mission platform."
Defense Secretary Robert Gates in March warned that the future submarine could be very costly.
"When that program really begins to ramp up, in the latter part of this decade, it will suck all the air out of the Navy's shipbuilding program," he told a House panel. "And so some tough choices are going to have to be made, either in terms of more investment or choices between the size of surface fleets you want and the submarine fleets."
The replacement submarines could cost roughly $7 billion apiece, measured in 2009 dollars, according to one independent estimate.
Expected to remain in service through the 2080s, the strategic boat has not yet been designed in detail. Only when more is known about the submarine's specifications can the service offer a realistic cost estimate, Benedict said at the breakfast forum, co-sponsored by the National Defense University Foundation and the National Defense Industrial Association.
"The size, diameter, of the [missile] tubes ... plays heavily on costs," he said. "The speed at which that submarine is required to not only surge to a patrol area -- [the] flank speed -- but also then patrol speed [affects costs]."
Another potential military requirement for the new boat will be its survivability; a submarine that operates quietly at high or low speeds would be harder to detect, he said.
Though the craft would be designed for the nuclear mission, Benedict would not rule out the idea that it could take on a conventional role sometime in its service, much as the Navy has spun off a conventional "SSGN" version of its Ohio-class vessels.
"We are making no design limitations in this program that would preclude future capabilities, much like we have in [the] Ohio [class]," he said.
During the Bush administration, the Defense Department proposed building a non-nuclear version of the Trident D-5 submarine-launched ballistic missile for "prompt global strike," a mission that would allow Washington to hit a target anywhere around the world within 60 minutes.
However, Congress banned testing or production of the so-called Conventional Trident Modification, citing concerns that Russia or China might misinterpret the launch of such a missile as a nuclear salvo, triggering an international crisis. The emphasis in developing a prompt global strike weapon has since shifted to an Air Force ground-based missile platform, potentially deployable by 2015, that is viewed as less likely to be destabilizing (see GSN, July 1, 2009).
Benedict left open the possibility that Washington might change its mind on the matter.
"We will design the appropriate requirements and cost for the Ohio [class] replacement program as a strategic [nuclear] deterrence platform," the admiral said. "If, at some point in the future, there are other capabilities that the leadership and the administration wants, then we'll look at how we would modify it, much as we did the SSGN. But we are not designing the Ohio replacement program specifically to have any conventional prompt global strike capability."
The Navy currently maintains four Ohio-class boats that have been converted to the SSGN configuration, which allows them to carry conventional cruise missiles and special operations forces. However, to date, no conventional prompt-attack weapons have been fielded.
Under the "New START' nuclear arms control pact, signed by the U.S. and Russian presidents in April, the United States would maintain 240 Trident D-5 submarine-launched ballistic missiles.
That is down from today's 288 deployed Trident missiles, which carry a total of 1,152 warheads, according to nuclear force analysts Robert Norris and Hans Kristensen.
The service could retire two of its SSBN ballistic-missile submarines toward the end of this decade, leaving it with 12 such vessels, according to the Defense Department's Nuclear Posture Review, a soup-to-nuts assessment of strategy and forces completed in April.
A reduction in the Ohio-class boats, though, is not expected to affect the total quantity of 240 nuclear weapons deployed across the strategic submarine fleet.
The future submarine will remain equipped with Trident D-5 ballistic missiles, at least for an initial period, according to Benedict. Retaining the D-5 weapon will help maintain continuity during a 13-year period between 2029 and 2042, when the Ohio-class vessels gradually retire and their replacements transition into the force, he said.
"From a cost standpoint, maintaining one strategic weapons system adds tremendous value," said Benedict, referring to the D-5 missile. "Being able to focus the integration from the [submarine] platform only -- rather than to have two variables, a new [strategic weapon system] as well as a new platform -- reduces risk.
"If you look at this program," he added, "we have always tried to hold one stable and move the other. So [we] either adjust the platform and hold the [nuclear weapon system], or hold the platform and design a new [weapon]."
Some nuclear experts have said the service could save money by basing the design of its Ohio-class replacement on that of the smaller Virginia-class submarine, which potentially could carry shorter missiles without a major redesign.
However, if the D-5 is to fit inside a Virginia-class design, the service would have to modify the submarine with a "humpback" silhouette to make it capable of housing the weapon's long missile tubes, Kristensen noted in an interview yesterday.
In fact, according to some observers, a weapon system as large as the D-5 is no longer necessary in light of a reduced international threat and White House plans to cut the nuclear stockpile.
"Why would you continue to build a D-5 missile that can carry as many as 12 warheads when you're only [planning] to carry four, to remain under the New START caps?" said one former nuclear officer, who requested anonymity. "A smaller, C-4 sized missile seems a lot more appropriate."
The Navy first deployed the Trident C-4 nuclear-armed ballistic missile in 1979, and phased it out beginning in the 1990s as the D-5 entered service. Each C-4 missile could carry no more than eight warheads and fly only two-thirds of the D-5's 7,000-mile range.
The D-5 is "a mighty big missile to commit to carrying for the next 50 years," agreed Kristensen, who directs the Federation of American Scientists' Nuclear Information Project. "You may not need a missile with as long a range as the D-5, because there's no one out there with a capability to hunt these ballistic missile submarines any more."
A diminished threat would suggest the submarines have more freedom of movement, allowing them to steam closer into target areas than might have been the case in the past, he suggested.
Thus far, the Navy has maintained that the D-5 is still a military necessity, but officials might change their minds "if it costs you another $50 billion [to] build a system to house such a big missile," said Kristensen. He noted that several years remain before the submarine design must be finalized.
The Nuclear Posture Review acknowledged that "there appears to be no credible near or midterm threats to the survivability of U.S. SSBNs," but said the Pentagon "aims to anticipate potential threats" in designing the new submarine.
The Navy today is building 108 updated "life-extension" versions of the D-5 missile, which it plans to begin fielding in three years. The modified D-5s will include newly produced rocket motors, remanufactured flight hardware and modern guidance instruments.
"The D-5 has been deployed for more than 20 years and is expected to be deployed for at least another 32, making it operational longer than any other missile system," Benedict said. The life-extension variant will remain viable through 2042, "matching and possibly extending its service life to that of the Ohio-class submarine," the admiral noted.
In the coming years, though, the $25 million per-copy cost of the D-5 missile could grow, Benedict said. As NASA and military service demand for solid-rocket motors declines, the aerospace industrial base will shrink and "the cost to produce and maintain D-5 missiles will significantly increase," he said.
Construction of the first Ohio-class replacement submarine is slated to begin in 2019, Benedict said.
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