Global Security Newswire
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Pentagon Said Likely to Back New Design for Ballistic Missile Submarine
WASHINGTON -- The U.S. Defense Department is likely to pursue a brand new design for its next nuclear-armed submarine, following a Navy recommendation during a key program review earlier this month, according to experts and observers (see GSN, Sept. 27).
The Pentagon's Defense Acquisition Board on December 9 completed an initial design review meeting on the so-called "SSBN(X)" effort, spokeswoman Cheryl Irwin confirmed last week. However, she indicated the department was not ready to release the review's results.
If approved by defense acquisitions czar Ashton Carter, the replacement submarine for today's Ohio-class ballistic missile vessels would enter its first major acquisition program phase, called "Milestone A."
A recent Congressional Research Service report estimated it would cost roughly $70 billion to replace the 12 ballistic missile submarines expected to populate the U.S. fleet by the end of this decade. The nation currently fields 14 Ohio-class boats.
The Navy has not released total cost projections for the new underwater craft, but has estimated it would spend $29.4 billion on the effort between fiscal 2011 and 2020. That figure, though, excludes costs for roughly two subsequent decades during which the 12 new submarines would be built and delivered.
The next-generation submarine is to initially carry today's Trident D-5 nuclear-armed ballistic missiles, but later could be fitted with new-design nuclear missiles and possibly conventional weaponry (see GSN, Aug. 10).
The first Ohio-class submarine to be replaced reaches the end of its 42-year service life in 2027. One subsequent vessel is slated to retire each year after that, with the last submarine expected to age out in 2040. The SSBN(X) submarines are to enter the fleet between 2029 and 2042.
One pivotal decision believed likely to come out of the Defense Acquisition Board review pertains to the approach the Navy will take in developing and building the replacement submarine. In an official "analysis of alternatives" that also has not been released, the Navy considered three possible design concepts for the Ohio-class follow-on, according to a recent Energy Department report.
First, the Navy could base its design on the Ohio-class vessel. This would have the potential benefit of saving much of the cost involved in designing a new submarine, which one 2008 estimate pegged at roughly $7 billion. However, service officials have said this approach would have the disadvantage of locking in older technologies that fail to meet the Navy's needs.
For example, it could be difficult to include in an Ohio-class design the silencing technologies the Navy believes are needed to combat modern detection equipment that future adversaries might field, among other features, according to naval sources.
Second, the service could alter the Virginia-class attack submarine design so that it could carry ballistic missiles. This approach could also offer cost-cutting advantages and transition the service to a smaller ballistic-missile vessel at a time when traditional Cold War nuclear threats are receding, according to analysts.
On the downside, modifying the more diminutive Virginia-class vessels would give the submarines a "humpback" appearance -- thanks to the insertion of a compartment for the large D-5 missiles -- and that could result in reduced capability in such areas as speed, maneuverability and stealth, the Navy has argued.
"A Virginia Insert SSBN would require redesign of the Virginia and would have technical and operational shortcomings and risks," the CRS report quoted the Navy as stating in March.
That leaves the Navy endorsing a new-design approach, the third option considered for the SSBN(X) in the service's analysis of alternatives, according to program experts. Though a new-design submarine involves additional cost, the Navy recently tailored back its size and speed requirements for the boat, defense leaders said this fall.
An "emphasis on affordability is already being applied to the next-generation ballistic missile submarine, where we are trimming [design] requirements without compromising critical capability," said Defense Secretary Robert Gates, appearing with Carter at a September 14 press briefing.
Pentagon-watchers said this month's Milestone A meeting was likely to have resulted in a schedule for the new submarine's development and testing, as well as possible cost-reduction goals for the program.
"The big problem is going to be money, because no one knows what they're going to cost," Norman Polmar, a longtime Defense Department consultant on naval issues, told Global Security Newswire yesterday.
There is little debate, though, over the basic necessity of replacing today's aging submarines.
"To maintain an at-sea presence for the long-term, the United States must continue development of a follow-on to the Ohio-class submarine," stated the Pentagon's Nuclear Posture Review, an assessment of strategic forces and strategy completed in April. "Since the lead times associated with designing, building, testing, and deploying new submarines are particularly long, the secretary of defense has directed the Navy to begin technology development of an SSBN replacement."
In February the Navy said that "owing to the unique demands of strategic relevance, [the new submarines] must be fitted with the most up-to-date capabilities and stealth to ensure they are survivable throughout their full 40-year life span," according to the Congressional Research Service.
Among the new capabilities the service is seeking in the new submarines is a nuclear fuel core that would last as long as the vessel, an improvement on the Ohio-class reactors that required midlife refueling, the October 28 CRS report states.
Whether Carter and his defense buying panel have fully backed all of the Navy's requests for SSBN(X) remains unclear, but it is "almost 100 percent certain" that the Pentagon will opt for a new design, one congressional source said last week.
Critics say, though, that the Navy analysis of alternatives failed to seriously assess the prospects for viable alternatives to a new design, effectively setting up the idea of designing a boat from scratch as the only acceptable option.
"That's the beauty of the Goldilocks approach, is that two options will always be unacceptable and then you land on the one you prefer anyway," Hans Kristensen, who directs the Federation of American Scientists' Nuclear Information Project, said in an interview yesterday.
The recent design review was also expected to decide whether the submarine will feature 16 or 20 missile tubes, according to the Capitol Hill aide and others who asked not to be identified in discussing the sensitive matter.
Each tube would be capable of launching a single D-5 ballistic missile or a future ballistic missile of up to the same size, but also might be able to fire multiple smaller weapons, according to experts.
To cut costs, the Navy is believed to be pressing for 16 missile tubes in the new submarine, though that does not mean that a new-design vessel would be smaller than the Ohio-class boat, which has 24 missile tubes, according to the CRS report.
In a recent briefing, "the Navy stated that an SSBN(X) would probably be about the same size and have roughly the same displacement as an Ohio-class submarine, even though it might have only 16 or 20 missile tubes," according to the congressional report. "Over time, technological advancements tend to add weight to a submarine design (compared with the same submarine produced 30 years earlier)."
In part because of technologies the Navy has long embraced to insulate the submarine's nuclear-reactor propulsion system, "there are real physical limits to how small you can make it," Kristensen said of the next ballistic missile submarine.
Polmar argued, though, that the Navy should consider using newer and smaller quieting technologies, such as "active" silencing approaches that cancel out reactor noise with other noise. Both of the analysts also said that if the Pentagon could accept a more limited patrol range for its next ballistic-missile submarine, the reactor and the overall size of the craft could be smaller.
"We don't have to stay as far at sea as we did during the Cold War," Polmar said.
On Capitol Hill earlier this year, lawmakers urged the Navy to consider buying a submarine smaller than the Ohio class -- such as a variant of the Virginia class -- that would be limited to launching a less-sizable missile like the Trident C-4, the weapon that the D-5 replaced.
"I think you ought to ask the engineers about a missile that might fit in the smaller submarine rather than the multibillion dollars you might have to sink into a replacement for the Ohio-class submarine," House Armed Services Committee Chairman Ike Skelton (D-Mo.) told Navy Undersecretary Robert Work at a July hearing.
Work responded that the Navy had considered using the C-4, but opted instead to go with the D-5, even if that effectively ruled out using a Virginia-class design.
Rear Adm. Terry Benedict explained to a Capitol Hill breakfast audience the same month that retaining D-5 missile capability in the new submarine would help maintain continuity during a 13-year period between 2029 and 2042, as the Ohio-class boats gradually retire and their replacements transition into the fleet. Benedict directs the Navy Strategic Systems Planning office.
Though the decision would allow the Navy to avoid the cost and developmental risk of undertaking both a missile- and submarine-development program at the same time, it also would mean the Ohio-class replacement must be large enough to fit the D-5, which has a range of roughly 4,000 nautical miles.
"At the outset, we have a predecisional notion that we're going to keep the D-5, making other [submarine] options straw men," Kristensen said.
Polmar agreed that the Navy should seriously consider using the C-4 or a new-design missile that is roughly 35 feet in length, as it could still offer the service some 3,000 nautical miles in range.
Under the New START nuclear arms control agreement -- a U.S.-Russian pact currently on the Senate floor for a ratification vote -- the Pentagon anticipates capping its Trident D-5 missile force at 240.
Today the fleet carries 288 deployed D-5s, armed with a total 1,152 nuclear warheads.
The reduction in two vessels by the end of this decade is not, in itself, expected to affect the number of D-5 warheads fielded at that time, according to nuclear force analysts Kristensen and Robert Norris of the Natural Resources Defense Council. The numbers would allow for a slightly higher average warhead loading on each missile, if the Pentagon desired.
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