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CG(X)

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CG(X) may use the hull of the Zumwalt class
Class overview
NameCG(X)
Operators United States Navy
Preceded byTiconderoga class cruiser
Cost$3.2 billion (forecast for lead ship)
In commission2017
Planned19
Buildingnone
General characteristics
Tonnage20,000-25,000 tons
Installed powerNuclear
PropulsionElectric
Armament512 VLS

The CG(X) program, also known as the Next Generation Cruiser program, is a US Navy program to replace its 22 Ticonderoga class cruisers after 2017. Original plans were for 18-19 ships, based on the 14,500 ton Zumwalt class destroyer but providing ballistic missile defense and area air defense for a carrier group. A reassessment in 2007 means that the CG(X) program may be split into two classes, fourteen Zumwalt-sized "escort cruisers" and five 23,000 ton ballistic missile defense (BMD) ships. There has been political pressure for some or all of these ships to be nuclear powered, which would give them the hull classification symbol of CGN(X).

The Analysis of Alternatives (AOA) for the CG(X) program was due in Q3 2007, but the Navy is now not expected to announce a preferred design concept until early 2009[needs update]. This has put in doubt the original timetable which called for the procurement of the first ship in 2011 for commissioning in 2017.

Background

In the early 1990s, the US armed forces had to respond to new threats and budgets after the end of the Cold War. The Navy's response was the the Surface Combatant for the 21st Century (SC–21) program. This envisaged a destroyer called DD–21 and a planned cruiser called CG–21. Budget cuts in November 2001 meant that SC–21 became the less ambitious Future Surface Combatant program. The DD-21 was renamed the DD(X), which is about to begin construction as the Zumwalt class destroyer. By April 2002, the DD(X) was to be the "foundation" for a family of surface combatants, including CG(X) as the successor to the CG–21. The Ticonderogas will reach their retirement age of 35 years between 2021 and 2029, although the Navy may use upgrades to extend their lives to 40 years.[1]

Design

Hull

In April 2002, John Young, Assistant Secretary of the Navy for Research, Development and Acquisition, stated that "the DD(X) hull will be the base from which they propose the design changes necessary to evolve this to CG(X). That could include various things from lengthening the hull and changing the size, but it will be, to our view, likely the basic hull form shape, appropriately sized and with the proper features added to accommodate the CG(X) mission".[2] The Chief of Naval Operations claimed in 2005 that "the DD(X) hull and propulsion plant will be spiraled into the CG(X) platform with about 80% design overlap".[3] In the same testimony, he claimed designing a new hull would cost about $4bn.

However, concerns began to grow about the stability of the Zumwalt's hull - naval architect Ken Brower said in April 2007 that "as a ship pitches and heaves at sea, if you have tumblehome instead of flare, you have no righting energy to make the ship come back up. On the [Zumwalt ], with the waves coming at you from behind, when a ship pitches down, it can lose transverse stability as the stern comes out of the water - and basically roll over."[4] There were also doubts whether the Zumwalt hull was big enough to accommodate ballistic defense weapons, and a possible nuclear propulsion system. In July 2007 came the first suggestions that the AOA might recommend a two-class solution, a 14,000 ton "escort cruiser" based on the Zumwalt's stealthy "tumblehome" hull, and a ballistic missile defense ship of 23,000 tons.[5] The latter would use a more conventional shape than the tumblehome, as its use of radars to search for missiles while on station would make a stealthy hull pointless.[5] In July 2008, Roscoe Bartlett of the House Seapower subcommittee stated that it was "unlikely the [Zumwalt ] hull could be used in the CG(X) program".[6]

Propulsion

The CG(X) will use the IPS electric propulsion system of the Zumwalt, as of the FY09 budget estimates in February 2008.[7] The Zumwalt's gas turbines are capable of generating 78 MW,[5] and that was thought barely sufficient for the radar and future weapon systems on the CG(X) - the working assumption is that the entire ship's electric load, including a Theater Ballistic Missile Defense (TBMD) radar will consume 31 MW.[8] In July 2008, Young said that "for the most capable radar suites under consideration, the [Zumwalt] hull cannot support the radar".[9]

Meanwhile members of the House Projection Forces Subcommittee had been pressing the Navy to use nuclear power for major combatants, partly as a response to concerns about the price and availability of oil. They prompted studies in 2005 and 2006, the second of which stated that nuclear power broke even at an oil price of $70–$225/barrel for escort ships of 21-26,000 tonnes with heavy radar use.[8] This led to a requirement in the FY2008 Defense Authorization Act[10] that all major combatant vessels be nuclear powered unless it was not in the national interest.[11]

The Navy has studied nuclear power as a design option for the CG(X), but has not yet announced whether it would prefer to build the CG(X) as a nuclear-powered ship - it would add $600–800m to the initial cost of the ship, but save on running costs.[8] Under normal budgeting practices, long lead-time items for nuclear propulsion would need to be procured in FY2009 if the main ship is to be procured in FY2011. If the two-class solution is pursued, it seems probable that the escort cruiser would use gas turbines like the Zumwalt, and the larger ballistic missile defense ship would be nuclear powered, and hence would be known as the CGN(X).

The AOA apparently looked at two options, using two of the Seawolf class submarines' 34 MW reactors, and halving the 209 MW double reactor used in aircraft carriers.[5] The first option would not even match the Zumwalt for power, while the second option probably wouldn't fit into the Zumwalt hull. On the other hand it would give plenty of headroom for future weapon systems such as directed-energy weapons and railguns, hence the proposal for the BMD ship of a larger hull with nuclear propulsion.[5]

Sensors

The CG(X) radar system is likely to be a development of the AN/SPY-3 dual-band radar of the Zumwalt class. It will also be influenced by the replacement for the AN/SPQ-11 Cobra Judy missile-tracking radar on USNS Observation Island. As mentioned above, a future Theater Ballistic Missile Defense (TBMD) radar is being modelled as consuming 31 MW of electrical power, compared to 5 MW for the AEGIS system on an Arleigh Burke-class destroyer.[8]

Weapons

A CG(X) based on the Zumwalt hull would lose one or both of its guns, and replace them with more VLS launchers for SM-2, SM-3 and SM-6 SAMs. However, the Zumwalt's lack of capability in air defense and BMD was cited as a major reason for the near-cancellation of the class in July 2008.[12] Recent intelligence that China is developing targetable anti-ship ballistic missiles based on the DF-21[13] appears to be shaping the Navy's thinking on the CG(X)'s capabilities, when previously the Zumwalt's air defense was believed to be good enough to justify delaying the introduction of the CG(X).[14]

The Kinetic Energy Interceptor (KEI) program is developing new weapons against ballistic missiles, but the KEI missiles take up six times more space than SM-3's and a Zumwalt-sized hull could not carry a meaningful number.[5] The KEI may be dropped from the CG(X) program.[5]

History

The CG(X) program was announced on November 1 2001. An initial requirement for 18 CG(X) was raised to 19 under the plan for a 313-ship Navy in 2005.

The Maritime Air and Missile Defense of Joint Forces (MAMDJF) AOA lasted from mid-2006 and continued until the end of 2007, but a public decision is not now expected until early 2009. The FY2009 budget calls for procurement of the first CG(X) in 2011, and the second in 2013, but these may be deferred.

See also

Notes and references

  1. ^ O'Rourke, Ronald (2007-02-01), Navy Aegis Cruiser and Destroyer Modernization: Background and Issues for Congress (PDF), Congressional Research Service, RS22595
  2. ^ "News Transcript 29 April 2002". Department of Defense. 2002-04-29.
  3. ^ Statement Of Admiral Vern Clark, U.S. Navy Chief Of Naval Operations Before The House Armed Services Committee Projection Forces Subcommittee (PDF), House Armed Services Committee Projection Forces Subcommittee, 2005-07-19, p. 11
  4. ^ Will DDG-1000 Destroyers Be Unstable?, Defense Industry Daily, 2007-04-12, quoting Cavas, Christopher P (2007-04-02), "Is New U.S. Destroyer Unstable?", DefenseNews
  5. ^ a b c d e f g Cavas, Christopher P (2007-07-26), "25,000-ton cruiser under consideration", Navy Times
  6. ^ Opening Statement of Ranking Member Roscoe Bartlett on Navy Destroyer Acquisition Programs, Committee on Armed Services, 2008-07-31
  7. ^ Fiscal Year (FY) 2009 Budget Estimates Justification Of Estimates February 2008 Research, Development, Test & Evaluation, Navy Budget Activity 4 (PDF), Department of The Navy, February 2008, p. 250
  8. ^ a b c d Webster; et al., Alternative Propulsion Methods for Surface Combatants and Amphibious Warfare Ships (PDF), Naval Sea Systems Command {{citation}}: Explicit use of et al. in: |last= (help) Version presented at 2007 SNAME Maritime Technology Conference & Expo November 14-16, 2007, a year after the data were presented to the Navy as requested by Section 130 of Public Law 109-163.
  9. ^ Fein, Geoff (2008-07-11), "DDG-1000 Hull Can't Support Most Capable Radar Planned For CG(X), Pentagon Official Says", Defense Daily Quotes letter of 2008-07-02 from John Young to Rep. Gene Taylor.
  10. ^ H.R. 4986, originally H.R. 1585, passed on January 28 2008 as P.L. 110-181
  11. ^ O'Rourke, Ronald (2008-05-22), Navy Nuclear-Powered Surface Ships: Background, Issues, and Options for Congress (PDF), Congressional Research Service, RL33946 is a broad discussion of the issues relating to nuclear propulsion
  12. ^ Cavas, Christopher P (2008-08-04), "Missile Threat Helped Drive DDG Cut", DefenseNews
  13. ^ Military Power of the People’s Republic of China 2008 (PDF), Office of the Secretary of Defense, p. 2 (p12 of PDF)
  14. ^ "John Young - Assistant Secretary Of The US Navy For Research, Development And Acquisition", Jane's Defense Weekly, 2005-01-12

Further reading

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