REPORT OF THE

DEFENSE SCIENCE BOARD

TASK FORCE

ON

SUBMARINE OF THE FUTURE

July 1998

OFFICE OF THE UNDER SECRETARY OF DEFENSE

FOR ACQUISITION & TECHNOLOGY

WASHINGTON, D.C. 20301-3140
This report is a product of the Defense Science Board (DSB). The

DSB is a Federal Advisory Committee established to provide

independent advice to the Secretary of Defense. Statements,

opinions, conclusions, and recommendations in this report do not

necessarily represent the official position of the Department of

Defense.

This report is UNCLASSIFIED.
OFFICE OF THE SECRETARY OF DEFENSE

3140 DEFENSE PENTAGON

WASHINGTON. DC 20301-3140

DEFENSE SCIENCE

BOARD

MEMORANDUM FOR UNDER SECRETARY OF DEFENSE (ACQUISITION &

TECHNOLOGY)

SUBJECT: Final Report of the Defense Science Board Task Force on

Submarine of the Future

I am forwarding the final report of the Defense Science

Board Task Force on Submarine of the Future.

This report examines how nuclear attack submarines (SSNs)

best serve the nation's future defense needs. The Terms of

Reference directed that emphasis be placed on operational utility

of future generations of submarines (beyond the New Attack

Submarine (NSSN)) and the impact of the littoral environment on

submarine design and operation in the context of joint

operations.

The Task Force quickly recognized that near term decisions

concerning submarines will impact their use in our naval forces

over the next 50 years and that a very long view of submarine

technologies and missions is needed. In consequence of this

conclusion the Task Force presents three primary recommendations:

1. The NSSN should continue and evolve leading to a next

generation submarine in about 2020 that is large,

possesses a nuclear propulsion plant similar to the NSSN,

and contains a new, flexible payload interface with the

water. This last item, the payload interface, is an

example of the Task Force central theme of devoting

design effort to the "front end" of the submarine.

2. For existing submarines, the number of submarines

required to maintain one submarine on station (called the

"K" factor), can be improved to meet deployment

requirements, but possibly at the cost of reactor core

lifetime. The Task Force recommends measures to improve

this ratio, although not at the expense of diverting

innovative design efforts from the "front end."

3. Initiate immediately a wide open look at future submarine

and applicable undersea and information technologies with

a concerted DARPA/Navy effort. Additionally, the

improved ability of the government to measure the ship's
performance can be exploited during the operational life

of the ship to incorporate improvements.

The Task Force believes that early implementation of its

recommendations can put in place a set of processes that will

assure the United States of a continuing leadership position in

submarine technology and submarine operational capabilities.

I endorse the Task Force's recommendations and propose you

review the Task Force Chairman's letter and report.

Craig Fields

Chairman
OFFICE OF THE SECRETARY OF DEFENSE

3140 DEFENSE PENTAGON

WASHINGTON, DC 20301-3140

DEFENSE SCIENCE

BOARD

MEMORANDUM FOR CHAIRMAN, DEFENSE SCIENCE BOARD

SUBJECT: Final Report of the Defense Science Board Task Force on

Submarine of the Future

Attached is the report of the Defense Science Board Task

Force on Submarine of the Future. This study was requested by

the Under Secretary of Defense for Acquisition and Technology.

The Terms of Reference directed that emphasis be placed on

operational utility of future generations of submarines (beyond

the New Attack Submarine (NSSN)) and the impact of the littoral

environment on submarine design and operation in the context of

joint operations. The guidance provided in the Terms of

Reference focused attention on the future naval environment, the

role of the submarine, potential new submarine capabilities, and

processes for developing any new technologies that may be needed

by future submarines.

The Task Force quickly recognized that near term decisions

concerning submarines will impact their use in our naval forces

over the next 50 years and that a very long view of submarine

technologies and missions is needed if this study is to b e useful

to DoD and to the Navy. In this long view, the Task Force

concludes that the emerging politico-military environment and the

rapidly changing technology environment are such that the nuclear

attack submarine will remain an essential and enduring element of

our naval force structure. The unique combination of stealth,

mobility, endurance and versatile offensive power have no valid

competitor in the set of missions to which attack submarines

apply today or in the foreseeable future. In consequence of this

conclusion the Task Force presents three primary recommendations

(and has provided the draft implementing memoranda to make clear

the intent of the recommendations):

1. The NSSN should continue and evolve leading to a next

generation submarine in about 2020 with the following

properties:

l A large nuclear submarine

0 Propulsion plant similar to the NSSN plant

l A new flexible weapons interface with the water

2. For existing submarines, the number of submarines

required to maintain one submarine on station (called the

"K" factor), can be improved to meet deployment
requirements, but possibly at the cost of reactor core

lifetime.

l The Task Force endorses such measures but cautions they

should not be allowed to exacerbate an already serious

inventory problem.

l Include in the next generation SSN an improved K factor

with potential extensions of SSN life that are possible

without change to the back end of the boat.

3. Initiate immediately a wide open look at future submarine

and applicable technologies with a concerted DARPA/Navy

effort by:

l Navy executing platform development

l Maximizing industrial inputs

l Using performance measurement techniques to maximum

extent possible to stimulate intellectual competition

of ideas. The improved ability of the government to

measure performance can be exploited during the

operational life of the ship to incorporate

improvements.

The Task Force believes that early implementation of its

recommendations can put in place a set of processes that will

assure the United States of a continuing leadership position in

submarine technology and submarine operational capabilities and

will serve to ensure the best technologies for submarines on an

affordable basis.

The Task Force is especially appreciative of the support

provided by its advisors and of the generous contribution of time

and intellectual input from the many briefers and from senior

Navy leadership knowledgeable of submarine operations and

technologies.

I thank the Task Force members and the talented group of

government advisors for their hard work and valuable insights.

Task Force Chairman
THE UNDER SECRETARY OF DEFENSE

3010 DEFENSE PENTAGON

WASHINGTON, D.C. 20301-3010

ACQUISITION AND

TECHNOLOGY

MEMORANDUM FOR CHAIRMAN, DEFENSE SCIENCE BOARD

APR 23 1997

SUBJECT: Terms of Reference--Defense Science Board Task

Force on Submarine of the Future

You are requested to establish a Defense Science Board (DSB)

Task Force to assess how attack submarines should serve the

nation's defense needs in the 21st century.

The winning of the Cold War-an outcome to which US

submarines contributed significantly-has led to a shift in the

structure and the employment of all our armed forces. In

particular, the Department of Defense has been forced to truncate

the SEAWOLF program in favor of a smaller, more flexible, more

affordable platform. The imminent start of New Attack Submarine

(NSSN) construction marks an appropriate juncture for an

assessment of the operational utility of the subsequent

generations of attack submarines.

The US is no longer confronted by a one-dimensional threat,

but by several actual and potential widely distributed regional

threats; this has brought about a shift in the Navy's focus from

open water to littoral regions, and the Task Force should

concentrate its attention on that circumstance. A submarine's

stealth is especially valuable in that environment, as

sophisticated weapons proliferate and make it increasingly

difficult for surface ships to operate near an adversary's

shoreline.

There continues to be a strong movement toward "jointness"

among the armed services, as urged by the Goldwater-Nichols

legislation, and exemplified by the call for seamless integration

made by the Chairman of the Joint Chiefs of Staff in Joint Vision

2010. The Task Force should explore the submarine's contribution

to joint operations in the littoral. Significant resources are

being expended to improve that capability: cruise missile attack

against distant inland targets; intelligence collection;

surveillance and reconnaissance; early warning of threat

developments: mine delivery or minefield mapping; and covert

insertion/extraction of special operations forces.

It is expected that there will be a continuing shrinkage of

the resources allocated to US defense. The Task Force should
examine unit cost/capability tradeoffs in considering the design

of a submarine force appropriate to the future environments in

which naval warfare may occur. In exploring all of these issues,

the Task Force should examine the broadest range of alternatives

and be guided by the following questions:

What is the naval environment to be expected for the next 10 -

20 years?

What is the role of the Navy in the next 10 - 20 years?

What is the role of submarines?

What then is the ideal submarine or submarine force mix?

Why do submarines need more capability than they have today?

What new roles might be considered for a radically different

submarine and what might their characteristics be to effect

this paradigm shift?

What are the technology improvement barriers that need to be

overcome for very significant improvement of the ideal

submarine force mix or radically different submarines?

The Task Force should report its findings by the end of - Calendar Year 1997. An interim briefing of major findings should

be provided in September 1997 to allow meaningful input to any

new submarine initiatives in PR99.

The Director, Strategic and Tactical Systems and Director,

Defense Advanced Research Projects Agency will sponsor this Task

Force and provide funding and other support as may be necessary.

Mr. John P. Stenbit will serve as the Task Force Chairman. Dr.

Paris Genalis, Deputy Director, OUSD(A&T) Office of Naval

Warfare, will serve as the Executive Secretary and CDR David

Norris, USN, will serve as the Defense Science Board Secretariat

representative.

The Task Force will be operated in accordance with the

provisions of P.L. 92-463, the "Federal Advisory Committee Act," 

and DoD Directive 5105.4 the "DoD Federal Advisory Committee

Management Program." It is not anticipated that this Task Force

will need to go into any "particular matters" within the meaning

of Section 208 of Title 18, U.S. Code, nor will it cause any

member to be placed in the position of acting as a procurement

official.
Defense Science Board

Task Force on

Submarine of the Future

Mr. John Stenbit, Chairman

Dr. Paris Genalis, Executive Secretary

1
TABLE OF CONTENTS

l Introduction

l Summary

l Observations

l Recommendations

l Other Observations on Attributes

of SSNs

l Appendices

3

4

8

32

33

46

2
INTRODUCTION

This report format is a reproduction of the

final briefing charts with additional short

commentary on each chart.

3
SUMMARY

l SSNs are a key and enduring element of the

current and future naval force - a “crown

jewel” in America’s arsenal

l We need more, not fewer SSNs

l Near term, invest in/evolve the front end

and payload of the sub, not the propulsion.

l DoD needs to widen participation and

reallocate tasks in the research,

development, and acquisition of SSNs

Based on the military and technological forecasts on which it has been briefed,

the Task Force concludes that nuclear attack submarines (SSNs) will remain

an enduring element of the naval force structure.

The SSN force level forecasts based on budget expectations are noted to be

substantially lower than those recommended by the QDR, and the United

States may require more, not fewer SSNs.

The traditional emphasis on advances in SSN propulsion and quieting must

shift to connectivity, sensors, weapons, adjuvant vehicles, and interfaces with

the water.

Because of their uniqueness, the only real testing of these systems will come

from ourselves, not competition with other nations’ programs. To maintain

our lead position, the government must inject dynamic performance

verification to spur the rapid detection of shortcomings.

4
TASK FORCE MEMBERSHIP

Mr. John Stenbit, TRW, Chairman

Dr. Paris Genalis, OSD(A&T)/S&TS/NW, Executive Secretary

Members

Mr. Joe Amato, Private Consultant

Amb. Linton Brooks, Center for Naval Analyses

Mr. Al Ellinthrope, SRI International

Mr. David Heebner, Private Consultant

RADM Frank Lacroix, SAIC

Dr. Reuven Leopold, SYNTEK

Dr. David Mann, Private Consultant

Mr. Mark Silverman, TRW

ADM Bill Smith, Center for Naval Analyses

Dr. David Stanford, SAIC

Government Advisors

CDR Jamie Foggo, OSD(A&T)/S&TS/NW CDR Norman Moore, OSD(A&T)/S&TS/NW

RADM Edmund Giambastiani, OPNAV N87 RADM Thomas Steffens, SOCOM

CAPT Karl Hasslinger, OPNAV N87 CDR Brad Weiner, OSD Net Assessment

Mr. George Leineweber, OSD(A&T)/S&TS/NW Dr. David Whelan, DARPA TTO

Executive Support

CDR Dave Norris, DSB Secretariat

Mr. Christopher Bolkcom, SAIC

Special Advisor to the Chairman

Mr. Jim Woolsey, Shea & Gardner

5
ABSTRACT OF TERMS OF REFERENCE

l What is the naval environment to be expected for the next 10-

20 years?

l What is the role of the Navy in the next 10-20 years?

l What is the role of submarines?

l What then is the ideal submarine or submarine force mix?

l Why do submarines need more capability than they have

today?

l What new roles might be considered for a radically different

submarine and what might their characteristics be to effect

this paradigm shift?

l What are the technology improvement barriers that need to be

overcome for very significant improvement of the ideal

submarine force mix or radically different submarines?

The Task Force’s terms of reference provided the analytical framework which

guided the study and deliberations.

While the terms of reference emphasize the next few decades, the Task Force

has noted that today’s design decisions will impact the next 50 years.

6
BRIEFINGS

Government

Bettis Atomic Power Laboratory

Central Intelligence Agency

COMSUBDEVRON 12

COMSUBLANT

Congressional Research Service

DARPA

Defense Intelligence Agency

Joint Staff, J-8

Knolls Atomic Power Laboratory

NAVSEA OS-Naval Reactors

NAVSEA PMS 404

Naval Surface Warfare Center

Office of Naval Intelligence

Office of Naval Research

OPNAV staff

. N091

. N23

. N6

. N81

. N87

PEO SUB (Seawolf, NSSN, Sub R&D)

USCINCSOC, J-7

Commercial and NonGovernment

Center for Strategic and Budgetary Assessments

Draper Laboratory

Electric Boat company

Newport News Shipbuilding

SAIC

Other

Mr. Anthony Battista

Mr. Gerry Cann

Dr. Johnny Foster

Dr. Andrew Krepinevich, National Defense Panel

ADM William Owens, USN (Ret)

Dr. Michael Pillsbury

Mr. Norman Polmar

CDR Jonathan Powis, RN, British Embassy

Dr. Lowell Wood

In addition to receiving fifty briefings, the Task Force spent a day aboard

Seawolf and visited the Electric Boat facility at Groton, Bettis Atomic Power

Laboratory at Pittsburgh, and Knolls Atomic Power Laboratory at

Schenectady. Verbal and written inputs were also received from CINC Pacific

Command, CINC Central Command, CINC Strategic Command, CINC US

Forces Korea, CINC US Pacific Fleet, and Commander Fifth Fleet.

7
OBSERVATIONS

8
BIG PICTURE MILITARY TRENDS

l Multiple, simultaneous, changing geographic foci

- Regional crises will require wide range of capabilities

l More stealth, agility, and self-defense required

l Commercial technology, available to all, driving information dominance

l Proliferation of technology in sensing, guidance, and targeting significantly

increases weapons effectiveness

l Separation of ID and shooter

- Precision strike

- Much smaller forces

l Diversity of missions - increases potential for dangerous asymmetries

l Availability of technology/info reduces decision cycle time, reduces warning

time, and increases need for rapid response capabilities

First, the US has moved, is moving, and will continue to move away from a single, dominant

geographic threat focus. The United States will be faced with multiple, simultaneous, dynamic,

and dangerous regions of interest.

Second, our deployed forces will be at risk of surprise attack from sources with surprising

capabilities. These forces must be much more self reliant and have robust defenses. Stealth,

agility, and self-defense will be critical.

Third, continued development of information technology will make available to all countries the

capability to find, target, and strike adversaries with precision from long range with destructive

effect. This will put our air, land, and surface sea forces increasingly at risk.

Fourth, these evolutions will separate the detection of targets from the shooter, allowing precision

strikes from great distances with smaller forces. The speed and flexibility of connections between

the shooter and the detector will become the determining factor in the engagement.

Fifth, the Navy’s role in these diverse missions will find it operating close to and across the

enemy’s shoreline. Potential asymmetries, such as those attributed to mines, conventionally

powered submarines, and anti-ship cruise missiles, challenge the Navy’s ability to operate in this

littoral environment.

Finally, the time window for military responses will compress at both the tactical and strategic

level. Future adversaries will not allow the United States months to transport forces, establish a

logistic train prepare, and attack. Similarly, future adversaries will likely emphasize mobility and

deception in battle to increase their survivability, suggesting the need for quick responses to

fleeting intelligence and targeting information.

9
WORLD FROM DOD PERSPECTIVE

in the next 10-20, then 50 years

l l0-20 years in the future l Later - up to 50 years

- No plausible strategic competitor - Plan on at least one strategic

l increasing number and locations of competitor

regional threats l Russian technology nucs &

- Current platforms still exist, but equipment, industry

effective kills per unit have l China uses economic &

increased military muscle to become

- Regional conflicts closing more aggressive

exchange ratio from “1000:1” in - Decisions now will impact on

Gulf capabilities then

l Advanced technology available to - Plan on

all l Technology diffusion

l Higher casualties accelerating

- Weaker alliances l Recurring regional crises

l Shorter lived

l More tenuous

l Fewer overseas bases and more

restriction on use

Current DoD programs appear to match the consensus vision of the environment over

the next 15 to 20 years: no superpower rival, US involvement in multiple locations,

and current platforms will be sufficient because their effectiveness will be increased.

There is also agreement in recognizing that the exchange ratio of 100:1 that we

gained in the Gulf War is unlikely to be repeated due to the diffusion of technology

and the expected strategy of seeking to maximize US casualties in the hope that we

will leave. There will be weaker alliances that will be more temporal in nature and

will have more restrictions on the use of overseas bases.

On the other hand, the Task Force is concerned about extrapolating these programs

and plans into the latter part of the 50 year period. It is obvious that the decisions we

are making now will impact on that time period. We are particularly concerned that

the technology diffusion will accelerate and that the subsequent threat to our forces

will increase significantly. We believe it is prudent to expect a strategic competitor in

the timeframe which will make recurring regional crisis much more dangerous and

unpredictable.

1 0
DOD ISSUES

l DoD must expect in both time frames

- Ability to influence peacetime situation

- Area of action will be closer to “enemy” than to home

- Protect freedom of sea/air commerce

- Vulnerable to casualties from small threats

- Global information collection/dissemination

l Deterrence, presence, and reassurance

requirements will continue

- Need ability to impose will with fewer resources

Despite diminishing resources, DoD will continue to be

expected to maintain deterrence and global presence,

support our allies, and protect our vital interests from

adversaries.

Future challenges to realizing these expectations include

1.) the increased dependence on expeditionary warfare, 2.)

the attendant need to collect and interpret information on a

global scale, and 3.) increased vulnerability to casualties

from small weapons.
NAVY ROLE

l Strategic Deterrence -SSBNs

- Possible fewer warheads/boat

- Re-use extra platforms for off-shore firepower

l Protection of sea lanes and sea lift

l Presence/crisis response

l Global information collection

l Stand off force and defense projection

- Air power

- Conventional missiles (cruise or ballistic)

- Theater missile defense (TMD)/Air Defense

l Littoral sea control and power projection ashore

- Logistics and ground force projection - Self Protection - Air/TMD/ASUW

- Mining and mine countermeasures - Disruption of shore infrastructure

- Anti submarine warfare (ASW)

Ballistic missile submarines (SSBNs) will continue to be a key member of the

strategic triad. (Under various options of treaties still being developed, the number

of warheads per boat may shrink.) SSBNs removed from their nuclear strategic

missions by the same treaties can be converted to deliver conventional missiles, thus

augmenting the land attack/strike capabilities of the Navy.

The traditional Navy role of sea control and defense of commerce will continue. In

the course of peacekeeping, there will remain a requirement for forward presence

and for a manifest ability to take the war to the enemy. The Navy’s ability to collect

information while in these roles remains a high priority.

Although “blue water” missions can’t be ignored, the sea-land (littoral) interface

will become more important. Projecting force to the land and protecting the land

from forces, whether aircraft, missiles, or long range munitions, are both required.

Finally, littoral sea control and self protection must be maintained in the potential

presence of undersea threats (enemy mines and submarines), surface threats, aircraft,

and missiles. Amphibious operations and continuing land strike in support of troops

on the ground will also remain as requirements.

12
WILL THESE NAVY ROLES ENDURE?

l We did not examine Navy-wide force mix

in future scenarios

l We expect the Navy roles to endure

- Inventory, inertia, and tradition

- Operations independent of basing

- Enduring covertness

- Heavy lift will always be by sea

13
GABRIELLI AND VON KARMAN

2000

1000

500

The most celebrated work in the area of lift-to-drag ratios is an article by von

Karman and an ex-student of his named Gabrielli, published in the late fifties.

Their centerpiece is a plot illustrated above. The right-hand bounding line has

since been exceeded slightly by super-tankers and by their aircraft equivalents

like the 747.

This graph shows that sea power (curves 2, 3, 5, 6, and 10) are the most costeffective, in terms of horsepower per ton, of delivering a payload, such as

ordnance or unmanned vehicles, to a distant location. The illustration supports

the Task Force’s assertion that Navy roles will endure.

14
WHAT IS THE NAVY DOING ABOUT THIS?

l On-going force structure trends l Redistribution of missions

- Logistics 8 -TMD - Aegis

-Fire support

- CVN * -De-emphasis on ASW

-Increasing jointness and

- SSN 00 connectivity and synergy

l Reduced R&D

- Surface

combatants + l Planned procurement will not provide

for even the reduced force levels

8

projected

- Amphib.

- Air wing #

- SSBN *

Because of the changing national security environment, there is an

ongoing reduction in the number of platforms in the fleet, a

redistribution of missions, and reductions in R&D and

procurement. For instance, the move away from the Cold War

Soviet threat has caused ASW to be de-emphasized, almost

completely in surface and air activities.

The Task Force notes that the SSN fleet is experiencing

proportionally the greatest reduction in overall strength.

The Task Force believes that force structure priorities must be

reviewed because they are inconsistent with the trends we perceive.
l

l

ATTRIBUTES OF AN SSN

“Unique”

- Stealthy

l Acoustic & non-acoustic

l At all speeds

l Open ocean & littoral

- High endurance

- Mobile

“Pretty Special”

- Cost up front vs. O&M

l Complex integrated system

- Heavy weapons against surface

combatants

- Covert Intelligence

- Covert weapons- surprise

- Reduced number of personnel at

risk vs. other platforms

Matches Navy Roles

- Sea control

- Covert intelligence gathering

- Crisis response

- Covert strike

- Protection of off-shore forces

l ASW

l Anti-mine

l Covert special strike

l ASUW

l Blockade/barrier

- Presence

Our review identified some attributes of attack submarines that are unique to that platform and some others, which,

though not unique, are “pretty special. “ These traits enable SSNs to be key participants in the execution of several

Navy roles.

Stealth is the sine qua non submarine attribute. The US has paid a lot of attention to acoustic stealth over the years,

and we are improving in our ability to reduce non-acoustic signatures as well. While our submarines have become

increasingly more stealthy in all environments and at all speeds, their advantage has eroded due to technological

improvements of our potential adversaries’ systems --particularly in asymmetric threats like diesel submarines

operating at low speeds. Abundant energy available from nuclear reactors enables sustained high speed and

endurance at any speed, with the added benefit of being free from logistics considerations.

There are other attributes that the SSN shares with other platforms, though not all with a single platform, therefore the

combination is unique. The total life-cycle cost of an SSN is dominated by its construction; O&M is relatively small.

This factor inhibits building SSNs in sufficient numbers, but allows them to be used extensively as an integrated

weapon system. Their heavy torpedoes are excellent weapons against surface ships. Because they are stealthy, they

are excellent platforms for intelligence gathering and surprise weapon launch when the enemy is unaware. This

covertness allows detection of more data because the target is not as cautious as when aircraft or satellites are known

to be in view. The effectiveness of surprise weapon strikes can be greater than normal because they attack targets

which are not at heightened alert.

While it is often stated that visual presence is a major attribute of surface combatants, the effect on a potential

adversary of thinking an SSN is in his area can be very important as well by causing him to curtail transport activities

and to change the deployment of his sea forces to more protected locations. Such “presence through uncertainty” is a

valuable attribute.
SSN ATTRIBUTES VS. MILITARY BIG PICTURE

l Stealth, endurance, and mobility are increasingly relevant

- SSN relatively immune to improvements in information

and weapons technology

- Provides “first on scene” capability covertly if required

l Already flexible but needs to be even more so

l Littoral environment requires more flexible payload, defense

and operational modes

l Firing from an initially covert position greatly complements

precision strike

l A large technological edge special for the US

l Available to do missions that others have de-emphasized

Technology advances and proliferation will make the submarine’s stealth, endurance, and mobility

even more important attributes in the future as surface and air forces become more vulnerable. An

SSN’s initially covert position allows surprise strikes, and its stealthy mobility provides the

opportunity to regain a new covert firing point and repeat the process (though without the surprise

factor).

This flexibility is currently limited by the amount and types of weapons carried and the inability to

communicate without giving up stealth. Both can be improved to take better advantage of the

effectiveness of precision weapons for land-attack.

As other platforms, pressed by new missions and new threat technology, have de-emphasized some

missions, the submarine has been available to expand in those mission areas, e.g., ASW.

17
SOME INTERESTING DECISION

DIFFICULTIES

l Fewer SSNs, more places to be, increased tasking,

and less deployed support

l Stealth vs. connectivity and time synchronization

l High tech Russian/ice/blue water vs. littoral

l Shrinking industrial base vs. need for capability to

stay “the best”

l Budget decisions not matched to assumptions leads to

“average,” not minimum regret

l A unique industrial base with no commercial analog

may be forced to live from hand-to-mouth for an

undetermined future

It is recommended that effort be invested in emphasizing to the design

community the centrality of stealth to the submarine and to the fact that stealth

is inevitably placed at some degree of risk by simply being in foreign littoral

waters, especially, by whatever releases of energy are needed to execute the

mission, such as communication transmissions or ordnance launching. It is

also noted that our experience in coastal waters is limited and we need

information about, for instance, acoustic transmission phenomena, bottom

topographies, and current fields.

It is important to note that these dilemmas can cause "budget-driven decisions

to ignore the serious dangers of choosing “average” paths. If, as we believe,

SSNs will not just be useful, but crucial in several future scenarios, not dealing

with these difficulties now will lead to major failures in our national security at

precisely that time when we have limited alternatives. DoD planning must

emphasize getting to the least worst outcome in future scenarios, because

averages do not apply to single events. SSNs are particularly useful in

avoiding the “worst” outcomes.

18
WE ARE BUILDING TOO FEW SSNS

l QDR and Joint Staffreviews of force structure have concluded 50

to 70 SSNs are required

- Without overbuilding inventory we will have at most 40 during critical

periods

- These reviews do not anticipate a strategic competitor in these periods.

l Current threats allow all forces to be effective

l Diffusion of high technology will increase the threat to forces in

different ways

l Sensing and localization at and above the surface and precision

long range weapons will put surface/air forces at risk in the 20-50

year time frame

l Decisions are being made using current threat/force combinations,

not future trends

The decision concerning proper SSN construction rate should be reevaluated.

It is understandable that when current forces are very effective, continuation of

plans to use them into the future is normal. However, the Task Force believes

the threat trends discussed previously will reduce the effectiveness of surface

ships significantly within 30 years, while leaving the SSN relatively immune

to threat escalation. This dynamic change argues that we should have more,

non-vulnerable platforms available in the second quarter of the next century,

and therefore we should accelerate SSN construction to a rate capable of

sustaining current force levels.

19
80

60

POTENTIAL SSN FORCE LEVELS, 1998-2045

Depending on post FYDP procurement rate

35 year life for 640s, 688s, SSN-21s, NSSNs

0 5 10 15 20 25 30 35 40 45 - -

Year

Ronald O'Rourke Congressional Research Service, 24 June 1997

This graph shows projected SSN force levels resulting from various

NSSN build rates and assuming a 35 year ship life. The 35 year life

assumption is optimistic, since its replacement of the current 30

year SSN life is not currently planned by NAVSEA.

However, the graph shows that even under this optimistic scenario,

SSN force level will dip below the QDR level of 50 unless a NSSN

build rate of 2 per year or greater is achieved. At the current ship

life of 30 years, the dip effect is even more pronounced.

Moreover, 35 year ship life may be impractical for all older classes

because of limited reactor core life and need to refuel late in the

ship’s life.

2 0
NSSN IS A MAJOR STEP TO THE

SUBMARINE OF THE FUTURE

Uses technology to enhance affordability

- Simpler power plant

- Modularity

l Construction - Design - Plugs

Production work force is down by a factor of ten at Electric

Boat - lower overhead rates

Increased flexibility for introducing/changing electronics

Stealth equal to or better than Seawolf

Advanced Swimmer Delivery System (ASDS) interface

Non-penetrating masts

Re-configurable torpedo room

Larger lock-out/off-loading chamber

We found the New SSN (NSSN) to be a significant enabler for future growth and exploitation

of future technological advances. It uses technology to enhance not just performance, but also

life cycle affordability via major system and component simplifications and a balanced

design/capability approach. For example:

* It incorporates a simple and very efficient nuclear propulsion plant.

*The modular design allows modules to be constructed and tested off-hull, then inserted

as independent units, without requiring special interfaces between them.

*The design also offers the possibility of clean transverse cuts of the hull which permits

the design and installation of mission specific plugs during construction. These

features, plus the reduction of manpower at the ship yards, have allowed technology

insertion to save cost.

*The combat system has been designed using mostly commercial off-the-shelf (COTS)

equipment in an open architecture to accommodate technology insertion (even prior to

delivery) to ensure the ability to track electronics technology growth throughout the life

of the submarine.

*The performance of the NSSN compared to Seawolf is favorable except for maximum

speed. However, NSSN is expected to have a greater tactical speed before either

sensor blinding or self noise become limiting factors. It also has some design features

which make it more flexible in operations near land.
THE NSSN SHOULD CONTINUE AND EVOLVE

l The previously noted prospective inventory

shortfall needs to be corrected

l The NSSN provides an effective basis for further

evolution

- Pay particular attention to the sensors and payload

l We should not stop an effective program until we

have a superior replacement

l We need to get comfortable with the “flexible

interface with the water,” and we need to design

and test it

l The “strategic pause” allows us this option

The Task Force was not asked about the NSSN, but since we make suggestions

for a significant change in future SSNs, we also must note that we do not

suggest the NSSN program to be stopped while waiting for such changes. We

need more SSNs, the NSSN is ready to be built, and it represents a platform

which can evolve significantly toward our goals for future SSNs. NSSN has a

first-rate propulsion system and the ship can be modified using inserted

sections to improve the interface with the water using more flexible techniques

than torpedo tubes and vertical launch systems (VLS). Improvements in the

sensor system can also be evolved quickly.

22
WE PROPOSE THAT THERE BE A TRANSITION

TO THE NEXT SSN AVAILABLE IN THE 2020s

l NSSN continues and evolves until then

l The next generation SSN must be a highly capable warship

with rapid response capability

- It should have flexible payload interfaces with the water,

not torpedo tubes, VLS and other special purpose

interfaces

- It should not constrain the shape and size of weapons,

auxiliary vehicles, and other payloads when they are used

- It is not only a large mother ship

l It will operate in “open ocean,” littoral, and land attack

modes

The Task Force suggests the follow-on to the NSSN be available in the 2020

time frame and that it be very different from the NSSN as currently designed.

In particular, it should not have torpedo tubes, VLS tubes, or other weapon

specific interfaces with the water. It should have a flexible interface which

does not constrain the shape and size of weapons, auxiliary vehicles, and other

payloads when they are used. We suggest using “bomb bay” techniques or

other large aperture openings, coupled with external storage of rapid-response

weapons. 

23
SSN FORCE MIX

l We recommend that the successor to NSSN be “large” nuclear

ship because

- We need to cover the world from the US => high transit speed,

independent logistics, and endurance

- We need to have flexible payloads=> large submarine size (10-12

meters diameter)

l The NSSN and future SSNs must have adjuvant systems

recognized as SSN payload instead of being a substitute or

extra class of ship

l Diesels (and other non-nuclear subs) appear to be best

characterized as local area warships (smart mine fields) with

an enhanced weapons effect range and sensors

l Can’t move much =>stay in critical pathways

- Deliver weapons effectively

The Task Force examined the possibility of providing more effective submarine forces using

smaller or non-nuclear ships, and firmly reaffirmed that “large” nuclear platforms are the

preferred choice. At expected force levels, the concept of a high-low mix is unpersuasive. This

picture is dominated by the requirement to deploy ships far from home bases and in widely

separated areas of the world, making speed and endurance very important. Large size is also

required because independent operations far from bases requires significant payload volume to

support multiple missions.

The Task Force also recognized that operations close to enemy shores will require using

adjuvant vehicles for various missions, especially in shallower water. We foresee significant

missions in surveillance, reconnaissance, mine-removal, people delivery, and others for such

vehicles used as a part of the overall capability of the SSN. While considering use of other

vehicles independent of the SSN, we rejected that path because the coordination requirements

will necessitate very close control by the SSN in any case.

Diesel and other conventional propulsion ships can not move as effectively as nuclear ships.

Staying virtually still, diesel submarines are useful for nations to block critical, near-shore areas,

because their sensors and weapons are effective over a larger range than mines. But the US

requirements involve going to these critical areas, not protecting approaches to the United

States.

24
SSN FORCE MIX (2)

l British compared fewer nucs with more diesels for “200 mile

range” operations and chose nucs

l The rest of the world will note these advantages of diesel subs

for operations near their shores and we will confront

situations which will have these platforms as our opponents.

They will be good at what they do. They may be

supplemented and/or replaced by off-shore deployed sensors

with land-based attack capability.

l Just because we choose not to build diesels, we must learn

from the development of such ships for

- Technology infusion

- Threat understanding

- Operational development

- Training and tactics for close range engagements

The British Navy made the same choice - nuclear propulsion - even when the

mission was assumed to be within 200 miles of home.

Coastal defense is the niche claimed for short-legged conventionally-powered

submarines - the impetus for submarine development resided for a long time

in France where it was hoped to be a cost-effective means of holding the

British fleet at bay. (In the modem era a better alternative for a small country

might be the use of sensor fields on the sea floor and land-based missiles

instead of diesel submarines.) Ships require maintenance, and their crews

require training and practice, and these factors have been found to mandate a

fleet of at least six or so ships, to maintain proficiency for one or two deployed

units.

However, there is an active market for diesel submarines in the world, and we

must expect to contend with them. Therefore, we should recognize that threat

and develop technologies for close-range engagements which will be very

likely when we “stumble” into the vicinity of a “stationary” submarine.

25
ELECTRIC DRIVE

l The US has a significant advantage in SSN performance because we

have overcome the constraints of the current mechanical propulsion

system. However, future progress will be difficult.

- Electric drive potentially allows

- Significant geometric design flexibility, especially with “integrated stern”

- Increased torque for lower RPM

- Better distribution of power to ship and payload and special propulsion

- Sharing of technology of power conditioning, control and distribution

- Use of “direct conversion” reactor

l We expect SSNs in 2040 may use electric drive, but we recommend

NSSN and its immediate successor use evolutions of the current

propulsion and concentrate development on the non-propulsion part of

the ship and its payload.

l However, if electric drive is available from other programs, earlier

insertion could be considered.

At present, our submarines have three kinds of internal energy distribution

systems; mechanical, electrical, and hydraulic. Mechanical is used for and only

for propulsion, hydraulic is being superseded by electrical, and electrical

already does all the rest. It is argued that an all-electric ship would permit a

flexible assignment of energy; the very large quantity now fenced off for

propulsion and unavailable elsewhere could, at low ship speeds, be used, for

instance, in weapons launch, or making fuel for adjuvant submersibles. In

fact, a fully all-electric ship would use a “direct conversion” reactor, removing

the requirements for turbines and other power plant machinery.

Even though the Task Force recognized the positive aspects of this argument,

we recommend that the next generation SSN not include electric drive. We

believe the resources required for such a change should be used to deploy a

much more effective “front-half’ of the ship and that there are not sufficient

resources within the submarine community to do both effectively.

26
USE OF A LIMITED NUMBER OF

PLATFORMS MUST BE IMPROVED

l Ratio of fleet to “on-station” positions (K factor) is -5

l Decreasing (i.e., improving) this ratio increases the margin the

country has in use of these assets for global presence

l The next generation SSN design requirements should include

actions to improve this factor

l To improve this ratio, we should consider

- A longer life platform

- Less maintenance down time

- Off-platform training efficiency - simulation

- Automation

- Connectivity to allow remote expertise for special tasks

- Logistics improvements

- Innovative manning/crew rotation

- Forward staging of critical support

- Ability to rearm/resupply forward

If, as we expect will be the case, the demands placed on submarines are going to increase

because of the increased need for their stealthiness, then the US will run into a numbers

problem no matter how many SSNs we produce. Increasing the time on station of each

ship will be important, not so much to reduce budget pressure by reducing the numbers of

SSNs, but rather to increase global presence of the submarine force in emergencies with

so few total platforms. We believe that improvements can lead to nearly continuous

deployment of the hulls, with crew rotations taking place in forward areas. That

eventuality has to be incorporated in today’s design practices - reduced maintenance

needs, reduced crew size, novel logistics support, automation/simulation, and especially a

flexible ordnance loadout to adapt easily to a variety of missions. For instance, more

automated shipboard equipment with effective shore-based simulators, may reduce the

need for extensive at-sea time between deployments in order to maintain crew

proficiency, thereby possibly improving the K factor.

Existing personnel policy regarding personnel operating tempo also drive K factor.

Improvements in this area, perhaps through innovative crew rotation, coupled with an

SSN designed from the start with these improvements in mind, would result in increasing

the availability of SSN assets. The Task Force is aware that any increased use of current

SSNs, designed for a single crew under current personnel, training, and operational

policies leading to a 30 year ship and propulsion plant life, will result in faster fuel

consumption and shorter life and exacerbate inventory shortfalls.

27
THE CURRENT DOD PROCESS IS NOT

LIKELY TO MEET THE CHALLENGES

l Non - integrated decisions

- Point solutions

l Too many small “pet ideas,” too little integrated

implementation

l Everybody “works” on “the program”

l Insufficient outreach to all of industry

l DoD should concentrate on defining requirements

and measuring performance

- Contractors concentrate on solutions and delivery

The DoD process in general, and the SSN acquisition decision process in

particular, is unlikely to meet the challenges our recommendations will

present. Within a closed community, even if vigorous debate precedes a

consensus, there cannot be sufficient dynamics over the long run. Such a

systems relies on the personal capability, maturity, and judgement of

individuals to accept criticism of their ideas. It is a tribute to the quality of the

leadership of the “silent service" that the system produces such fine equipment

and people, but the Task Force believes that the requirements for change imply

that the process must become more open, more dynamic.

28
CONCENTRATION ON THE NEXT SSN SHOULD

BE ON THE FRONT END OF THE SHIP

l The Navy should concentrate near-term efforts to develop

concepts for the platform and weapon delivery designs

l A program should be developed to define innovative payloads

- Sensors

- Torpedoes

- Missiles

- Mines

- Adjuvant vehicles

- ... and the defense against such weapons

l DARPA must collaborate with the Navy on this innovative

effort--potentially via ACTDs/ATDs.

The submarine will have to shoulder a wider responsibility than that of a torpedo boat, and to

enable that, our key recommendation is that the torpedo room be exorcised and the ship’s frontend be rearranged to create an open (free-flooding) space patterned after a cargo hold or, more

aptly, a bomb bay. That will remove the design constraints of 25 inch hatches and 21 inch

ejection tubes and, thus, widen the availability to the submarine community of the innovative

abilities of US industry, whose help will be needed in developing ordnance to handle, for

instance, land attack

We believe that this “bomb bay” innovation should be part of a redesign of the entire front end

that should include considering:

l eliminating the sail (and thus gaining speed and agility at shallow depth at high sea state and

reducing radiated- and self-noise)

l replacing the sonar sensors with an integrated system having much improved performance.

The Task Force is not unmindful of the difficulties that lie in the path of such an endeavor and

urge that DARPA and the Navy collaborate on it in order to best marshal a wide participation by

US industry. It is specifically suggested that DARPA take on the development of novel payloads

- low-cost, artillery-size precision guided munitions (PGM), adjuvant vehicles to extend mission

performance in inshore waters, stealthy means of launch, sensors, and other creative ways to use

the increased flexibility of the new platform design led by the Navy.

29
l Since the SSN represents a case of significant technological

superiority in favor of the US, care must be taken to prevent

that superiority eroding because of too “collegial” a process

versus one with constructive adversarial relationships.

l We must greatly strengthen the competition of ideas integrated

into the SSN program.

l We believe that government internal resources should shift

their focus from telling industry how to build things towards

developing techniques to measure performance in realistic

ways.

Since the SSN represents a unique “crown jewel” for the US, we are the only

ones who can challenge whether they are the best they can be. If we are the

best, then only we can measure performance well enough to see where

improvements can be made. Because even for SSNs the diffusion of

technology to other nations will cause our advantage to shrink in time,

particularly against non-air breathing conventional submarines and emplaced

sensors; we need to measure overall performance and detect the flaws and

elements in order to fix them. We can no longer rely on measuring average

performance every so often.

Building a constructive adversarial relationship between the contractors and

the government would increase the competition of ideas in the program. The

government should focus on measuring the performance of what is delivered

by industry, while industry should creatively develop alternative methods of

meeting requirements. Such increased competition of ideas will improve the

performance of both the products and the acquisition process. These same

measurement techniques can be used later in the SSN life to detect erosion in

performance.

30
MAINTAINING SUPERIORITY (2)

Progress in this area will be measured by more

innovation in the acquired SSNs and better

measurements of their performance before

acceptance.

The technologies developed to measure

performance more realistically will allow “selftest” and correction to be much more effective.

31
RECOMMENDATIONS

l The NSSN should continue and evolve, leading to a next generation submarine

in year 2020:

- Large nuclear submarine

- About same propulsion plant as NSSN

- Flexible weapon interface with the water

l For existing submarines, K factor improvement will help global presence

requirements during inventory shortfalls but will limit life

- Improve operational techniques to improve K factor for use during periods requiring

increased global presence with existing SSNs. Use of these techniques will

exacerbate the inventory problem in the long term.

- Include in the next generation SSN an improved K factor with potential extensions

of SSN life that are possible without change to the back end.

l Wide open look at future submarine by DARPA/Navy

- Navy execute on development of platform

- Maximum industrial input

- Maximize performance measurement techniques by government creates intellectual

competition of ideas

The Task Force offers three recommendations. First, the NSSN appears to be

a successful program and should be allowed to continue and evolve. The next

generation SSN after NSSN should reflect improvements in the “front end,”

e.g., flexible interface with the water, and feature about the same propulsion

plant as NSSN. Second, the Navy should examine ways to get more use out of

SSNs, through K factor improvement. Such improvements should be

consistent with the Task Force’s emphasis on the “front end” of the ship.

Ongoing, incremental design improvements in the existing NSSN propulsion

plant, combined with “front end” improvements suggested for the next

generation SSN, may result in an improved K factor without detriment to the

planned 30 year ship and propulsion plant lifetime. Lastly, DARPA and Navy

must engage in a cooperative effort to develop new payloads, encourage wider

industry participation, and create new performance measurement techniques.

32
OTHER OBSERVATIONS ON

ATTRIBUTES OF SSNs

33
ELECTRIC DRIVE

l Current propulsion train constrains SSNs

- Very long dimensions

- Extreme tolerance constraint

l 10-3 inches @ 100 feet of propulsion train

- Quieting of multiple sources coupled via this

train

- Torque limits minimum RPM

- Constrains volume usage

- Progress requires breakthroughs in

mechanical/thermal areas => special technology

Electric drive propulsion systems have already become common in large

cruise ships because they permit better arrangements within the ship, leading

to more revenue-producing space. Counterpart rearrangement advantages

exist for warships generally, including, of course, submarines. For the

submarine there is the additional great concern about stealth, the energy that is

radiated acoustically comes dominantly from the propulsion system, at least at

high speeds, and strenuous efforts are made to minimize it. Those efforts have

been extraordinarily successful, but their realization requires machinery

parameters (size, weight, and precision) that are at or near the limits of what

can be achieved. It is argued that electric motors will permit a substantial

advance in radiated noise control, circumventing the present-day mechanical

limitations.

34
DIRECT CONVERSION

Direct conversion of heat to electricity removes the turbines and

steam from the propulsion plant and allows greatly increased

internal design flexibility with quieter operations

The Panel is impressed with the youth, competence, approach

and enthusiasm of the teams working on the problem of direct

conversion from the reactor heat to electricity

Practical application of this technology may require decades, so

do not lose faith - keep it going

The goal of this program should be to enter the SSN fleet at the

earliest in the generation after the follow-on to the NSSN.

Heroic efforts should not be used to try to achieve this goal.

35
EFFECTIVE CONNECTIVITY NEEDS TO BE

EMPHASIZED

l SSN stealth is of paramount importance

l A bell-ringer to alert an SSN to decrease stealth for

connectivity on demand is vital.

- For constrained cases, e.g. task forces, can we provide more

effective bell-ringers using acoustics or other means

l An intemet-like protocol-based “asynchronous”

information transfer system (l06

 bits per second (BPS))

will allow SSNs to support their missions -- while

maintaining stealth

- Assumes SSN decides time delay between transfers

- Requires others to be “tolerant”

The Task Force concurs that the new missions anticipated for SSNs will

require much more connectivity with other forces. However, because stealth is

so important, we believe sufficient connectivity should be the goal, not

connectivity as good as other ships. In particular, exposing antennas to be a

part of a “morning” video teleconference should not be considered. The ship

should adapt its connectivity posture to complete assigned missions with

minimum compromise of its stealth. Therefore, in cases where an external

authority requires change in connectivity status, that authority must have a

bell-ringer capability available to tell the ships to change its posture.

Alternative solutions to the existing ELF system should be explored, including

localized systems for use within a task force, such as acoustic systems.

The use of “asynchronous” internet based systems for delivering targeting

coordinates and battle plans are perfect for SSN operations. These systems are

evolving for everybody, and they allow any subscriber to ask for data when it

wants to, not when a sender wants to transmit. Some missions, such as realtime adaptive air/missile defense, don’t work in this environment, but the SSN

does not contribute well in such cases anyway.

36
EFFECTIVE CONNECTIVITY NEEDS TO BE

EMPHASIZED (2)

l We believe that developments described to us to

provide stealthy - larger aperture, multi-band

antennas which provide 106 order of data rate BPS

need to succeed, and are much more important

than working on 107 - 109

 order data rate systems.

l We believe acoustic link R&D for very long range

(106 m) or network applications, should accelerate

The Task Force believes that successful completion of the deployment of

present programs to provide about a MBPS are required, but we question the

utility of pushing to greater bandwidths soon.

37
Improved acoustic quieting alone is not sufficient for

dominance, parity should be the expected case

- Detection ranges will be very short - however improving

sensors is important

- We currently are among the best at reducing radiated acoustic

noise

- Technology of both sensing and quieting is being deployed by

others

l We must assure that we are not “less than the best”

- Measure ship performance more often in more realistic ways

- Closed-loop detection-correction should become the norm

- Know how well sensors operate

ACTIVE VS PASSIVE ACOUSTICS

Historically US Navy submarines have been able to rely on an edge in acoustic

quieting. This advantage is declining and we must plan for parity in acoustic

quieting - not continued superiority.

Passive detection ranges are becoming ever shorter, but this dictates that we

must not flag in efforts to improve sensors and strive for some level of

advantage. Although we continue to be among the best, if not the best in

acoustic quieting, others are deploying the required technology and are closing

the gap, particularly in asymmetric situations, such as diesel versus nuclear

SSNs.

We must assure that we never become less than the best. In order to maintain

that level of performance, it is imperative that we measure our submarine

acoustic performance in the most realistic ways possible. Techniques need to

be developed that enable us to carry out closed loop detection and correction in

the course of normal operations so that we can continually tweak our own

submarine performance. This “tweaking” must include onboard assessment of

how well our sensors are performing versus the expected performance.

38
ACTIVE VS PASSIVE ACOUSTICS(2)

l Others have always planned that they will

be detected first

- We need to plan for this to happen to us

sometimes

l Fast reaction, short range response

l Countermeasures

l Use of active by us and confusing them

. Weapons

- Point defense

- Short range

- Shallow water

In the past our adversaries have had to plan for being detected first.

Consequently they have been forced to consider and develop strategy and

tactics to respond to this occurrence.

We must confront the same possibility and this situation dictates that we

develop the capability for fast reaction and short range response including the

use of countermeasures and active techniques to confuse the enemy.

Weapons, too, need reconsideration: It would be most desirable to have a

point defense capability that could operate effectively at short range and in

shallow water. Other techniques adapted to short range and shallow water

operations should also be considered and developed.

39
NON-ACOUSTIC SIGNATURE CONTROL

l Shallow depth operations will provide

significant non-acoustic signatures to enemies:

- Masts out of water

- LIDAR detection

- Low search rate sensors are effective in confined

areas

- Magnetics

- Hydrodynamic effects

- Biological

- Electromagnetic

The confined operating space of the littoral enhances the threat that relatively

unsophisticated detection devices coupled with elementary sensor-tocommand-to-prosecutor systems could exploit the SSN’s signatures and

relative inability to maneuver as freely as it might otherwise in open waters.

Consideration therefore should be given to the development of signature

control measures other than acoustics.

Continuing emphasis by the Submarine security program to determine

potential signatures that could compromise the submarine is also very

important to maintain our capability against sophisticated enemies. Moving to

more closed loop signature control will be enhanced as the government

develops better capability to measure performance.

If the SSN’s role includes “vanguard” operations as a prelude to a naval

operational maneuver from the sea or strike operations to support the joint

force commander, requirements may dictate near-surface tactical

maneuvering. To provide for the most effective survivability, such approaches

as reduced IR/RF masts, reduced wake, and LPI communications could loom

important.

4 0
MANEUVERABILITY/HYDRODYNAMIC

CONTROL AUTHORITY

l Shallow and constrained water operations requires

that greater emphasis be placed on maneuverability

and control authority, especially at low speeds

l Auxiliary active maneuvering devices and

innovative control surface design will be required

l Increased adaptability to environment, e.g.

bottoming, use of terrain masking

Operations in the littoral demand that the SSN be able to operate effectively

close to the land mass or in bodies of water that are enclosed and shallow.

With the SSN close to the bottom there is a greater need for control to prevent

groundings or damage from obstructions (such as wrecks or other hazards to

navigation). Also the event could cause a transient noise signature which

could possible be detected by either shore based sensors or diesel submarines

in the vicinity. Therefore, the ability to maneuver both in depth and heading is

needed to ensure that the position of submarine is accurately maintained.

At very low speeds the present day control surfaces would be only minimally

effective. The need, therefore, exists for some form of active auxiliary system

for low speed maneuvering and/or new designed control devices or surfaces.

In the future the SSN might not be able to avoid detection simply by its stealth

but must also take advantage of the environmental conditions such as bottom

terrain. This fact could require the SSN to replicate its surroundings if

ensonified by an active sensor.

41
HYDRODYNAMICS

l NSSN hull penetration with fiber is a good start

towards modifying sail height or “removing” it.

This is consistent with a goal of symmetric flow.

l We believe more volume will be required, therefore

length/diameter relationship allows fatter hulls with

slight performance improvement relative to NSSN.

l Shallow operations require more attention be paid

to hydrodynamic signature control

l Propulsor evolution needs to continue.

The sail is a major contributor to the sonar self-noise, to the radiated noise

acoustic signature, and adds greatly to the overall drag of the submarine hull.

The new fiber optic periscope is a good start by allowing for a reduced size

sail. Going the next step to a very small or no sail at all should be the goal of

any future design.

If additional volume is required for future designs then a submarine shape that

is larger in diameter (fatter) could be used with only a slight increase in drag.

The operations of the submarine in shallow water puts even more pressure on

the requirement for improved stealth including the hydrodynamic components.

Therefore, research needs to continue in hydrodynamic flow and signature

control.

Tied to the hydrodynamic signature control is a continuing effort in evolving

the SSN propulsor. This could go in several directions and would be tied to

the development of electric drive.

42
TACTICAL SPEED IS IMPORTANT

l Maximum tactical speed is limited by radiated

noise and sensor performance and determines

mission efficiency

- NSSN improved over Seawolf

l Transit time, and therefore maximum speed, is

important less than 25% of a mission

l Escaping from weapons is helped by acceleration

and maneuverability more than by speed

l Increases in tactical speed have more mission ’

leverage than increases in flank speed.

Speed is also an important factor in submarine performance. Due to the

relatively long transit times for US submarines to normal areas of operations,

high maximum speed is an essential attribute in increasing time on station

and/or getting to an emerging trouble spot.

Although the technological challenge associated with conducting evasive

maneuvers with au object having the size and mass of a submarines is

enormous, speed and acceleration will make a positive contribution to the

ability of the submarine to escape weapons.

Radiated noise and sensor performance are the governing factors in

establishing the maximum tactical speed. This parameter is a true

discriminator among submarines and efforts to increase tactical speed deserve

considerable attention. In fact, successful efforts to increase tactical speed will

provide more mission leverage than efforts to increase flank speed.
SSN LAND ATTACK INCREASINGLY

IMPORTANT

l Significantly improved target location and weapons

effectiveness allows land attack to become an

important SSN mission

l SSN based shore attack with the limited number of

weapons carried will pivotal to an integrated

campaign as the opening salvo

- Geometry

- Surprise

- Flight time

- Certainty of execution

l Large scale shore attack capability could be from

converted Tridents

In addition to the traditional and historical missions accomplished by submarines, land attack has

become a realistic and potent capability. As demonstrated during the Gulf War, attack

submarines can make a valuable and significant contribution to destroying critical land targets.

In the future there is potential for land attack missions where it may be too risky to sail surface

ships within range of the targets or there is a strong reason to retain the advantage of complete

surprise. In these scenarios the SSN becomes the perfect launch platform. Its ability to sail

within relatively close range of the target undetected furnishes it with unique ability to gain the

element of surprise. Surprise is compounded by the potential for reduced flight time of the

missiles due to the ability to covertly close the range to the minimum possible for sea based

platforms. Finally the ability to stealthily penetrate to such advantageous launch positions,

including favorable geometry to avoid terrain constraints, provides near certainty of successfully

executing the mission. Despite the limited magazine capacity of the SSN, the foregoing

attributes make the SSN a formidable vehicle for land attack as long as accurate targeting is

available and precision munitions are used.

In the event increased magazine capacity is desired for submarine launched missile attacks, it is

technically possible to convert Trident submarine missile silos to launch large numbers of

missiles in the land attack mission.

44
LAND ATTACK(2)

l In a real campaign across sea/land interfaces this

type of opening salvo is truly vital

0 These factors imply land-attack payloads that

should

- Be precision, high confidence, preferably to designated

aim-points.

- Have multiple “front-end possibilities”

l Integrated warhead

l Cluster of smaller, single shot to kill “warheadlets”

l Re-loadable, perhaps re-configurable selectable in-board

l Special purpose payloads

The element of surprise in an opening salvo from an SSN allows targets to be

attacked when their defenses are unprepared.

Depending on the specific circumstances there are a number of implications

for land attack payloads. First they should be capable of precision targeting at

designated aim-points with high confidence in their ability to perform the

intended mission. Second, given the variety of circumstances that may be

encountered, it would be highly desirable to provide a range of “front-end

possibilities” on the missiles. For example, one might consider an integrated

warhead, a cluster of single shoot to kill “warheadlets,” or other special

purpose warheads. Finally, it would be advantageous if the missiles could be

reloadable or re-configurable on-board the submarine. This would provide the

ability to revise the mission after the submarine was in theater, a very valuable

attribute in a changing scenario.

45
APPENDICES

46
APPENDIX A: ACRONYMS AND

ABBREVIATIONS

ACTD

ASDS

Asuw

ATD

BPS

CINC

COMSUBDEVRON 12

COMSUBLANT

DARPA

DoD

ELF

FYDP

ID

LIDAR

NAVSEA

NSSN

O&M

PEO SUB

QDR

R&D

SSBN

SSN

TMD

12

Advanced Concept Technology Demonstration

Anti submarine warfare

Anti surface warfare

Advanced Technology Demonstration

Bits per second

Commander-in-Chief

Commander, Submarine Development Squadron

Commander Submarine Force, US Atlantic Fleet

Defense Advanced Research Projects Agency

Department of Defense

Extremely Low Frequency

Future year defense plan

Identification

Laser RADAR

Naval Sea Systems Command

New attack submarine

Operations and maintenance

Program Executive Officer, Submarines

Quadrennial Defense Review

Research and development

Submarine, nuclear ballistic missile

Submarine, nuclear attack

Theater missile defense

U.S. Special Operations Command

Advanced Swimmer Delivery System

Vertical Launch System

47