Ships, Sensors, and Weapons
Undersea Warfare Programs 
Target an Expeditionary Future

Ships, Sensors, and Weapons

As the armed services re-orient themselves toward a greater emphasis on expeditionary warfare, the Navy continues to refine its ability to gain and sustain access, conduct network-centric operations, and project power “…From the Sea” in the 21st century. Accordingly, the focus of the Submarine Force research, development, and acquisition programs is also moving in that same direction. While still maintaining their ability to prevail in sustained “blue water” conflicts against world-class adversaries, America’s submarines are moving increasingly into the littorals of the world to face new challenges. Recent national tasking for increased intelligence, surveillance, and reconnaissance (ISR) missions in these areas are already outstripping their ability to address the current mission at hand. Moreover, within future joint force or coalition contingencies, U.S. submarines will be relied upon to be the first in, establishing clandestine – or deliberately overt – presence, well before the outbreak of hostilities. Their first mission will be to deter our potential adversaries, and if deterrence fails, they reserve the ability to launch a first strike from remarkably close range.

New Platforms for New Missions

While designed primarily for Cold War-era anti-submarine warfare (ASW) and to provide direct support to aircraft carrier battle groups (CVBGs), our present force of 51 USS Los Angeles (SSN-688) and Improved 688-class submarines is well equipped for both ISR and strike missions. Their inherent acoustic stealth, new and improved sensors, and vertical-launch missile tubes for Tomahawk land-attack missiles have prepared these increasingly venerable, yet still powerful, submarines for a wide range of contingency and wartime missions. Two new attack submarine classes currently under construction are especially well prepared to serve in expeditionary roles – the USS Seawolf (SSN-21) and USS Virginia (SSN-774) classes. 

Seawolf herself was commissioned in July 1997 and USS Connecticut (SSN-22) in December 1998. The third of the class, USS Jimmy Carter (SSN-23), is now under construction and will deliver in 2004. The Seawolf class was intended originally to be the successor to the 688 class and was designed to achieve higher submerged speeds, deeper diving capabilities, and a new order of machinery quieting. With new combat and sensor systems and an increased payload capacity, Seawolf has demonstrated superior warfighting capabilities for both deep-ocean and littoral missions. Jimmy Carter will be a unique multi-mission platform, with additional volume and an innovative ocean interface module for accommodating new capabilities in Naval Special Warfare (NSW), tactical surveillance, and mine warfare. In this regard, Jimmy Carter will embody many of the recommendations of the 1998 Defense Science Board study that called for novel payload capabilities and a more flexible interface with the undersea environment. 

USS VIrginia, caption follows
Combat Ready. USS Virginia (SSN-774) will expand on the ability of submarines to operate inside an enemy’s defenses not only for surveillance, but to deliver powerful precision weapons to targets on land or sea.

The 30-ship Virginia class will incorporate similar advanced acoustic technology, but with increased use of commercial off-the-shelf (COTS) components and modular construction techniques, it will be less expensive to build. Modularity allows for construction, assembly, and testing of systems prior to installation in the ship’s hull. This reduces costs, minimizes rework, and simplifies system integration. The modular design also facilitates technology insertion in both the new construction of future ships and back-fit into existing ships throughout their 30-year service lives.

Diagram of the USS Jimmy Carter (SSN-23)
USS Jimmy Carter (SSN-23) incorporates new innovations in submarine design

While the Virginia SSNs will perform traditional open-ocean anti-submarine and anti-surface missions, they are specifically designed for multi-mission littoral and regional operations. These advanced submarines will be fully configured to conduct mining and mine reconnaissance, Special Operations Forces insertion and extraction, battle group support, intelligence-collection and surveillance missions, sea control, and land attack. Furthermore, they have been specifically designed with an open architecture and system/component modularity to allow easy reconfiguration for special missions and emerging requirements. 

While the Virginia SSNs will perform traditional open-ocean anti-submarine and anti-surface missions, they are specifically designed for multi-mission littoral and regional operations

Takes you to article explaining Contruction Teaming Plan
Team Effort. The Virginia-class submarines are being built at both Electric Boat and Newport News Shipbuilding. Each shipyard constructs about one half of each ship, and for the most part builds the same sections each time. The shipyard designated as the "delivery yard" completes the final construction.

The first four Virginias are being constructed under an innovative teaming arrangement between General Dynamics’ Electric Boat Corporation (EB) and Newport News Shipbuilding (NNS), in which the two companies are constructing different portions of each ship. EB will assemble and deliver the first and third ship; NNS the second and fourth. Construction of Virginia began in 1998, and the second submarine of the class, Texas (SSN-775), began construction in FY 1999. Hawaii (SSN-776) will be laid down in 2001. Virginia-class acquisition will continue over the FYDP at a rate of one ship per year. Under Program Objective Memorandum (POM) 2002, production will increase to two ships per year beginning in FY 2007.

Building New Capabilities for Intelligence, 
Surveillance, and Reconnaissance

For close-in, non-provocative surveillance and reconnaissance in hostile coastal areas or in support of allied maritime forces, no other platform offers the vantage point or the endurance of a nuclear-powered attack submarine. But satisfying the increasing demand for submarine ISR services requires not only a sufficient number of platforms, but also state-of-the-art sensor systems capable of gathering a growing variety of signals, threat intelligence, and environmental data. Submarines in ISR roles also need robust communication pathways, both to receive tasking and to disseminate the vital intelligence information they collect. A number of new sensors and systems address this growing need.

Photo of the USS Emory S. Land, caption follows
The USS Emory S. Land (AS-39) keeps submarines ready while deployed to the Mediterranean Sea.

Acoustic Sensors, Processing Systems, 
and Fire Control 

In the area of underwater surveillance, for example, several new acoustic sensor, signal processing, and fire control systems are coming on line. These systems will build on our robust deep-ocean capabilities to provide even greater sensitivity to slow, quiet targets in shallow, coastal waters. Additionally, mine detection and avoidance have become key requirements for achieving and maintaining access to the littorals, placing additional demands on new sensors and systems.

For use as its primary long-range acoustic sensor, the submarine community is developing the TB-29A Submarine Thin-line Towed Array as a COTS version of the legacy TB-29 towed array. These arrays will be used to back-fit the Los Angeles-class submarines (both 688 and 688Is) and forward-fit the Virginia-class ships. They will provide greater capability than the current TB-23 Thin-Line towed arrays and will be more supportable because of commonality throughout the fleet. Coupled with the submarine A-RCI Phase II system, TB-29A arrays are expected to provide the same 400-500 percent increase in detection capability against submerged platforms as the current TB-29 has demonstrated. Technical Evaluation is scheduled for the TB-29A in FY 2001, and Operational Evaluation will follow in FY 2002 after the first three arrays are delivered to the fleet. 

These new sonar sensors with such superior detection capabilities must be coupled with more sophisticated – and more flexible – signal processing. The Acoustic Rapid COTS Insertion (A-RCI) Program is a multi-phase development that is supplanting existing legacy submarine sonar systems with a common, more capable and flexible COTS-based Open Systems Architecture (OSA) on SSN-688-, SSN-688I-, SSN-21-, and SSBN-726-class submarines. The powerful A-RCI Multi-Purpose Processor (MPP) allows development and use of complex algorithms that were previously well beyond the capability of legacy processors. More importantly, COTS-based processors and OSA technology and systems allow onboard computer power to grow at nearly the same rate as commercial industry’s, and will enable regular updates to both software and hardware with little or no impact on submarine scheduling. 

A key facet of the A-RCI program (designated AN/BQQ-10) is the Submarine Precision Underwater Mapping and Navigation (PUMA) upgrade. These software-processing improvements will provide submarines with the capability to map the sea bottom and register geographic and mine-like features. This ability to map the ocean floor and display the results in three dimensions will allow submarines to conduct covert battlespace preparation of the sea floor, as well as minefield surveillance and avoidance, with impunity.

A-RCI Phase II (FY 1999) provided substantial towed and hull array software and hardware processing improvements that significantly improved low-frequency detection capability. Phase III (FY 2001) augments the current Digital Multi-Beam Steering (DIMUS) processing on the Spherical Array with a linear beamformer and enhanced processing that improves medium frequency detection capability. Phase IV (FY 2001) will upgrade the high frequency sonar on late-generation SSN-688I-class ships. Each upgrade installs improved processing and workstation interfaces and built-in training software. Recent, real-world encounters have consistently demonstrated the overwhelming success of this program in restoring and maintaining U.S. acoustic superiority against likely adversaries. 

Photo of the sonar team aboard USS San Juan, caption follows
The sonar team aboard USS San Juan (SSN-751) conducts Acoustic Rapid COTS Insertion training.

Submarine combat control – or fire control – systems are also being upgraded and improved. Older legacy systems will have a more common, capable, and flexible open architecture under the Submarine Combat Control System Open System Enhancement Program. This program will be implemented in three phases. Phase I (FY 2000) introduces automated strike planning capabilities of the Tomahawk Weapons Control System (ATWCS), currently employed on strike capable surface ships, and an upgrade to Virginia-class-like data distribution and services. Phase II (FY 2002) further upgrades the processing capability and introduces advanced weapons improvement. This upgrade supports the Tactical Tomahawk (TACTOM) Weapon Control System (TTWCS) and the improved anti-diesel littoral torpedo (ADCAP CBASS). Later, Phase III (FY 2007) installs Virginia-class weapons-launch improvements and provides an at-sea, end-to-end launcher testing capability. The first Mk 2 Block 1C installation on a Los Angeles-class submarine has already been completed, with developmental and operational testing to support IOC scheduled for FY 2001. 

The BSY-2 Submarine Combat System was designed to meet the expanded operational requirements of the Seawolf (SSN-21)-class attack submarines. The system is fully integrated for sonar tracking, monitoring, and launch of all on-board weapons, including Mk 48 ADCAP/ADCAP MOD torpedoes, Tomahawk missiles, and mines. Significant advancements include the hull-mounted Wide Aperture Array (WAA) for rapid localization of targets, a 92-processor node flexible architecture (“FLEXNET”), and a fully integrated Interactive Electronic Technical Manual (IETM) supporting on-board and shore-based maintenance, operations, and training. Three systems have been procured, with the first delivered to the Seawolf in February 1995, the second to Connecticut in October 1997, and the third intended for Jimmy Carter.

The Navy’s first priority in its current UUV plan is the 
rapid development and deployment of a covert 
mine reconnaissance capability.

Non-acoustic Sensors 
The increasing demands on submarines for near-land ISR has raised electro-magnetic sensors to new levels of importance. The AN/BLQ-10 Electronic Support Measures (ESM) Suite, formerly known as Advanced Submarine Tactical ESM Combat System (ASTECS), will be deployed on the Los Angeles, Seawolf, and Virginia classes and will support operations in both the open ocean and in the complex littoral signals environment. The system consists of periscope-mounted antennas, broadband receivers, signal detectors, displays, and advanced processing and analysis equipment. The BLQ-10 will detect, analyze, and identify radar and communication signals from ships, aircraft, submarines, and land-based transmitters. Additionally, it includes a powerful radio direction-finding subsystem and will provide our ships an enhanced littoral intelligence-gathering capability, particularly when augmented with special carry-on signals intelligence (SIGINT) equipment. The AN/BLQ-10 ESM System entered development in October 1994, and successfully passed OPEVAL in June 2000.

Image of the Long-term Mine Reconnaissance system, caption follows
LMRS will Offer New Mine Ops Capabilities. The Long-Term Mine Reconnaissance System will enable submarines to conduct clandestine minefield reconnaissance by launching and recovering a vehicle able to operate autonomously for more than 40 hours.

Another exciting new technology for information gathering in coastal regions is that of Unmanned Undersea Vehicles (UUVs) — particularly those that can be launched and retrieved by submarines standing farther out to sea. The Navy’s first priority in its current UUV plan is the rapid development and deployment of a covert mine reconnaissance capability. The Long-Term Mine Reconnaissance System (LMRS) is in development to enter service in FY 2003 and will enable submarines to conduct clandestine minefield reconnaissance by launching and recovering a vehicle able to operate autonomously for more than 40 hours. Potential preplanned product improvement (P3I) enhancements are being reviewed to expand LMRS capabilities with Precision Underwater Mapping and Navigation and more cost-effective rechargeable energy sources. The Multi-Mission UUV Program, an outgrowth of LMRS, scheduled to start in FY 2004. This initiative is envisioned as building on the LMRS design by adding “plug and play” sensor packages for potential missions in electro-magnetic and electro-optical ISR, Indications and Warning, tactical oceanography, and remote ASW tracking. 

Enhanced Communications 
A key requirement for expanding the role of attack submarines in both intelligence gathering and joint operations is achieving an order of magnitude increase in communications connectivity. The High Data-Rate (HDR) Antenna will provide the Submarine Force with world-wide, high data-rate satellite communications for accessing the secure, survivable Joint MILSTAR Satellite Program in the Extremely High Frequency (EHF) band, as well as the Defense Satellite Communications System (DSCS) in the Super High Frequency (SHF) frequency band.

Photo of the High Data Rate Antenna, caption follows
HDR Offers New Connectivity. The first operational installation of the Navy’s new High Data Rate (HDR) Antenna was completed on USS Providence (SSN-719) in August 2000 and has already demonstrated a significant improvement in submarine connectivity.

The HDR antenna can also copy targeting information from the Global Broadcast Service (GBS). The first Rapid Prototype HDR Antenna was delivered to the Navy in June 1998 and has successfully completed testing. The first operational installation was completed on USS Providence (SSN-719) in August 2000 and has already demonstrated a significant improvement in submarine connectivity. Operational Evaluation is currently ongoing.

If Deterrence Fails – and Conflict Escalates…

Submarines already on scene for the ISR stages of a contingency are both well-positioned and well-prepared to support U.S. interests if the tactical situation escalates toward armed conflict. The first overt military action required of nearby submarines might be the insertion of Special Operations Forces (SOF) for covert missions in hostile territory. The new Advanced SEAL Delivery System (ASDS) is particularly designed for assignments of this type. This dry mini-submarine is 65 feet long and is operated by a two-man crew. It can carry a Navy Sea-Air-Land (SEAL) squad or similar teams from the other services for long-range clandestine insertions and extractions in support of special operations missions. ASDS will be launched either from a host submarine, much like the Deep Submergence Rescue Vehicle (DSRV), or from the well decks of amphibious ships.

Photo of ASDS, caption follows

ASDS diagram, caption follows
Advanced SEAL Delivery System (above); the diagram below illustrates various elements of ASDS, including the Thruster, Anchor, Transport Compartment, Battery, LIO Compartment, Operator Compartment, and Forward Looking Sonar.

Essentially, a “dry,” battery-powered mini-submarine, it will eliminate the extended cold-water exposure inherent with in-service, “wet,” submersible Swimmer Delivery Vehicles (SDVs) and will bring SOF team members into action with much less physical and mental fatigue. The U.S. Special Operations Command has funded all the ASDSs now planned for procurement. The first is home-ported with SEAL Delivery Team One (SDVT ONE) in Pearl Harbor, Hawaii, and is currently undergoing at-sea operational testing. Follow-on ASDSs are scheduled to be homeported in Hawaii and in Little Creek, Virginia (with SDVT TWO), and modifications to allow in-service submarines to host the vehicles are underway.

Image of swimmer operations from an SSGN.
Artist’s conception of swimmer operations from an SSGN.

New Torpedo Developments
If a shooting war breaks out at sea, the primary underwater offensive weapon of the Submarine Force is the Mark 48 Heavyweight Torpedo, effective against both surface ships and hostile submarines. This 21-inch diameter weapon has been in production since February 1972, and is carried by both attack and ballistic missile submarines. 

An improved Mark 48 Advanced Capability (ADCAP) Torpedo is now fielded on the Seawolf-, Los Angeles-, Sturgeon (SSN-637)-class, and Ohio (SSBN-726)-class submarines; it will also arm the Virginia-class attack submarines. A modification to the ADCAP (ADCAP MOD) will increase guidance/control speed and memory, and significantly reduce radiated noise. Both versions will combat fast, deep-diving nuclear submarines and high-performance surface ships and can operate with or without wire guidance using active and/or passive homing and preprogrammed search and attack procedures. A follow-on hardware upgrade, known as the Common Broadband Advanced Sonar System (CBASS), began development in FY 1998 and will further enhance the torpedo’s performance against modern SSNs and SSKs employing advanced countermeasures. ADCAP MOD upgrade production began in FY 1995, and between FY 2000 and FY 2004, a total of 522 will be completed. CBASS MODs are scheduled for implementation on 675 torpedoes between FY 2003 and 2007.

Tomahawks for Land Attack
If the developing scenario ashore demands a precision strike against critical targets early in the conflict, U.S. submarines are equipped to fire the A/N BGM-109 Tomahawk Land-Attack Missile (TLAM) from either torpedo tubes or vertical launchers. From their unique vantage point close to hostile coasts, submarines can often launch in complete surprise from under the enemy’s air-defense umbrella and depend on a short time of flight to increase the overall accuracy and effectiveness. TLAM is the Navy’s premier, all-weather, long-range, subsonic land-attack cruise missile, and it is deployed on surface warships as well. The TLAM/C variant is armed with a unitary conventional warhead, while the TLAM/D variant is armed with submunitions. TLAM is guided by an on-board Inertial Navigation System (INS) and Terrain Contour Matching (TERCOM) system, which correlates observed terrain contours with a map stored onboard to determine where the missile is. Additional accuracy is attained through multiple Digital Scene Matching Area Correlation (DSMAC) updates, which take digital pictures of the terrain and compare them with stored digital maps. The TLAM Block III upgrade improves accuracy and global strike capability with the addition of Global Positioning System (GPS) guidance capability and improved DSMAC IIA.

Photo of the TACTOM, caption follows
TACTOM will improve submarine covert precision strike capability.

Tactical Tomahawk (TACTOM), the Block IV upgrade to TLAM, will preserve Tomahawk’s long-range precision-strike capability while significantly increasing responsiveness and flexibility at significantly lower cost. The follow-on TACTOM improvements include in-flight retargeting, the ability to loiter over the battlefield to respond to emergent targets, satellite “backlinking” for battle damage assessment (BDA), and a new family of alternative payloads. The TACTOM program was initiated in FY 1998 and will reach IOC in FY 2003. Current plans call for the Navy to procure 1,353 TACTOM variants.

Photo of submarine launched Mark 48 ADCAP Torpedo, caption follows
The awesome power of the submarine-launched Mark 48 ADCAP Torpedo is clearly illustrated as it tears through a former destroyer escort during a combat systems test conducted by the Australian Navy.







Undersea Warfare and the MRC

In the event of a Major Regional Contingency (MRC) – either without warning or as the result of the failure of deterrence and the escalation of conflict – the attack submarine force will quickly become heavily tasked within the context of either joint or combined operations. In addition to continuing ISR missions now expanded to include Battle Damage Assessment (BDA), U.S. submarines will take the predominant part in “sanitizing” the undersea battlespace in preparation for the arrival of follow-on joint forces by sea. Similarly, their close-in precision strike capability will be called on frequently to neutralize enemy command and control nodes, time-critical targets, and hostile air defenses, thus preparing the way for manned aircraft strikes from aircraft carriers or forward bases. A major new initiative in this area is the proposal to convert four older Ohio-class SSBNs – excess to the impending START treaty limits – to SSGNs capable of carrying up to 154 TLAMs or TACTOMs in their reconfigured vertical-launch tubes, more than any other warship in the Navy. This would provide the U.S. with an unmatched combat power that is covert, survivable, forward deployed, and has a nearly unlimited endurance.

Image of the Advanced Deployable System caption follows ADS – Valuable to Littoral Surveillance. The Advanced Deployable System (ADS) is a passive acoustic undersea surveillance system designed for rapid deployment in littoral areas for the detection, classification, localization, and tracking of both underwater and surface targets.

Undersea Surveillance 
Securing and maintaining control of the sea, both in an MRC’s operational area and along the sea lines of communication (SLOCs) that support joint forces, requires effective means of detecting and interdicting enemy threats, surface and subsurface. The sine qua non of this capability is pervasive surveillance – of both large ocean areas and specified regions of particular importance. Largely as an outgrowth of the enormous effort expended on ASW during the Cold War, a number of new sensor and surveillance systems are coming on line. 

A major asset in this context is our fleet of T-AGOS Ocean Surveillance Ships – small, civilian-manned auxiliary towed-array vessels that play a prominent role in augmenting the Navy’s overall anti-submarine warfare capability. There are eight total ships in three classes: a three-ship monohull Stalwart (T-AGOS-1) class, a four-ship twin-hull Victorious (T-AGOS-19) class, and a single leased vessel, the R/V Cory Chouest. The Victorious class is a Small Waterplane Area Twin-Hull (SWATH) design that allows the ships to operate in relatively high seas. 

T-AGOS ships provide the platform for the Surveillance Towed Array Sensor System (AN/UQQ-2 SURTASS). The SURTASS ships provide passive detection of quiet nuclear and diesel submarines and real-time reporting of surveillance information to theater commanders. For passive sensors, they employ either a long-line passive sonar acoustic array or a shorter twin-line passive acoustic array. The twin-line system is our best operational shallow-water towed array and the only multi-line towed array in the Navy. It consists of a pair of arrays towed side-by-side from a SURTASS ship and offers significant advantages for undersea surveillance operations in the littoral zone. It can be towed in water as shallow as 180 feet, provides significant directional noise rejection, resolves bearing ambiguities without turning, and allows the ship to tow at higher speed. The twin-line Engineering Development Model is currently installed on the USNS Assertive (T-AGOS-9), and the first production model has been installed on the USNS Bold (T-AGOS-12). 

U.S. submarines will take the predominant part in “sanitizing” 
the undersea battlespace in preparation for the 
arrival of follow-on joint forces by sea.

With a Low Frequency Active (LFA) add-on to SURTASS, the system is capable of making long-range detections of both submarines and surface ships using a low frequency active sonar transmitter suspended beneath the T-AGOS ship. As a mobile system, SURTASS/LFA can be employed as a force-protection sensor wherever the force commander directs, including forward operating areas or in support of battle group activities. Only one LFA system exists, currently installed on board the R/V Cory Chouest. LFA will be transitioned to USNS Impeccable (T-AGOS-23), a single large (5,500-ton) SWATH ship designed specifically as a platform for the SURTASS towed array and its LFA adjunct, when it becomes operational in FY 2002. Efforts to develop smaller and lighter LFA-type active systems are ongoing.

Fixed Acoustic Surveillance 
For conducting acoustic surveillance and monitoring in delimited geographical areas of interest, two innovative new systems are under development. The Advanced Deployable System (ADS) is a rapidly deployable, short-term, large-area undersea surveillance asset, designed to detect, locate, and report quiet conventional and nuclear submarines in shallow-water littoral environments. ADS will consist of a Processing and Analysis Segment (PAS) contained in reusable, transportable vans and connected to the ADS sensor field by a shore cable. The Underwater Segment (UWS) is an expendable, battery-powered, wide-area field of passive undersea arrays. ADS will provide threat location information directly to tactical forces and contribute to the joint force commander’s real-time maritime picture in areas where timely surveillance is needed to maintain undersea battlespace dominance. 

ADS is in the Engineering and Manufacturing Development phase following a highly successful May 1999 Fleet Exercise Test that demonstrated the capability to detect and track a quiet diesel-electric submarine and provide real-time cueing information to tactical platforms. Incremental capability builds will provide a Trip Wire in FY 2003, a Small Field in FY 2004, and Large Field in FY 2006. 

Photo of T-AGOS Ocean Surveillance Ships, caption follows T-AGOS Ocean Surveillance Ships like USNS Loyal (T-AGOS-22) are small, civilian-manned auxiliary towed-array vessels that play a prominent role in augmenting the Navy’s overall anti-submarine warfare capability.

On a somewhat larger scale is the Fixed Distributed System (FDS), intended as a fixed, long term, passive-acoustic, ocean-bottom surveillance system. Currently under development is a more modern variant of FDS, called FDS-COTS, which will make maximum use of COTS components to upgrade the existing capability. Both versions consist of a series of arrays deployed on the ocean floor in deep-ocean areas, across straits and other chokepoints, or in strategic shallow-water littoral areas. Both also include two components: the Shore Signal and Information Processing Segment (SSIPS) that handles the processing, display, and communication functions; and the Underwater Segment consisting of a large area distributed field of acoustic arrays. The initial FDS program was suspended in 1993 following the deployment of the first system, designated FDS-1. Additional planned systems were cancelled due to high costs relative to the perceived threat after the breakup of the Soviet Union, and FDS-COTS was developed as a less-expensive follow-on version. Development of an all-fiber-optic hydrophone passive array will increase system reliability and performance, and may also reduce costs. System testing and evaluation are complete, and a contract is in place for the production of the next generation of underwater systems.

Deep submergence rescue vehicles, like Mystic (DSRV-1) pictured above aboard USS Dallas (SSN-700), continue to provide the U.S. and its allies a worldwide, quick-response submarine rescue capability unmatched by any other nation. Photo of the Deep submergence rescue vehicle, caption follows

Strategic Deterrence

While the Navy’s attack submarines prepare for participation in a wide range of potential littoral and expeditionary contingencies, the nation’s ballistic missile submarines – the SSBNs – continue their quiet strategic deterrence patrols – day in and day out – with little publicity or fanfare. The ultimate guarantors of the international security of the United States, they have performed this mission with proud dedication and near-perfect proficiency since 1960. The future of our seaborne nuclear deterrent rests on two key elements: the SSBN force and the TRIDENT missile system. 

The TRIDENT II (D5) missile.
The TRIDENT II (D5) missile.

The USS Ohio (SSBN-726)-class TRIDENT Fleet Ballistic Missile Submarines (SSBN) comprise the Navy segment of the nation’s strategic triad, which also includes long-range manned bombers and land-based intercontinental ballistic missiles. The SSBN is the most survivable and enduring leg of the triad, and thus remains one of the Navy’s highest policy, program, and operational priorities. All 18 of the Ohio-class SSBNs have been commissioned; the final ship of the class, the USS Louisiana (SSBN-743), joined the fleet in FY 1997. The Ohio-class submarines each carry 24 TRIDENT missiles – TRIDENT I/C4s on the first eight ships stationed in Bangor, Washington, and TRIDENT II/D5s on the ten ships stationed in Kings Bay, Georgia. Conversion of four of the C4 ships to carry the TRIDENT II/D5 missile began in FY 2000 and will be completed in FY 2008, with USS Alaska’s (SSBN-732) and USS Nevada’s (SSBN-733) conversions currently in progress. The first four Ohio-class submarines are scheduled for inactivation starting in 2003 to comply with the 1994 Nuclear Posture Review target of 14 SSBNs. USS Pennsylvania (SSBN-735) and USS Kentucky (SSBN-737) will shift homeport from Kings Bay to Bangor in 2003 to balance the strategic force. 

The UGM-133A TRIDENT II/D5 Submarine-Launched Ballistic Missile is the sixth generation of the U.S. Navy’s Fleet Ballistic Missile (FBM) program, which started in 1955. The D5 is a three-stage, solid-propellant, inertially-guided, submarine-launched ballistic missile (SLBM) with a range greater than 4,000 nautical miles and accuracy measured in hundreds of feet. TRIDENT II missiles are capable of carrying W76 or W88 Multiple Independently Targeted Reentry Vehicles (MIRVs). In operation, these missiles have been declared at eight MIRV warheads under the Strategic Arms Reduction Treaty (START). As the Navy continues to address future deterrence requirements against weapons of mass destruction, the TRIDENT II/D5 will ensure that the United States has a modern, survivable strategic deterrent. 
TRIDENT II/D5 missile construction continues with an inventory objective of 425 missiles for 14 TRIDENT II/D5 SSBNs in two oceans. Planned procurement through FY 2005 is 5 to 12 missiles per year.

The SSBN is the most survivable and enduring leg of the triad, and thus remains one of the Navy’s highest policy, 
program, and operational priorities.


The USS Alexandria (SSN-757) underway.
The USS Alexandria (SSN-757) underway.

Despite a dramatic downsizing in the decade since the Cold War, today’s Submarine Force is responding to the volatile demands of the 21st century by designing-in flexibility, both in computer and sensor systems and in hull and mechanical systems. Exciting new programs for ships, sensors, and weapons are already in place both to revitalize our existing force structure, and to bring on- line an entirely new generation of submarines specifically suited for the expeditionary missions of the new millennium.