BACKGROUND PAPER

Counterforce Issues for the

U.S. Strategic Nuclear Forces

January 1978

Congress of the United States

Congressional Budget Office

COUNTERFORCE ISSUES FOR THE

U.S. STRATEGIC NUCLEAR FORCES

The Congress of the United States

Congressional Budget Office

For sale by the Superintendent of Documents, U.S. Government Printing OfBce

Washington, D.C. 2M02

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PREFACE

In recent years, concern has grown that one element of

the TRIAD of U.S. strategic nuclear forces, land-based ICBMs,

might become vulnerable to a first strike by an improving Soviet

ICBM force. The fiscal year 1979 budget will present to the

Congress several programs that respond to this growing threat.

This background paper, prepared at the request of the Senate

Budget Committee, discusses the significance of the Soviet counterforce threat against Minuteman and the arguments for and

against the development of a similar U.S. capability. Together

with the forthcoming companion paper on retaliatory issues,

it supports a forthcoming Budget Issue Paper for fiscal year 1979

on strategic nuclear forces.

This paper was prepared by Robert R. Soule of the National

Security and International Affairs Division of the Congressional

Budget Office, under the supervision of John E. Koehler. The

author wishes to acknowledge the assistance of Virginia G. France,

David R. Martin, John Shewmaker, Carl R. Neu, Linda S. Moll, Nancy

J. Swope, and Patricia J. Minton. Cost estimates were provided by

Edward Swoboda of the Budget Analysis Division of the Congressional Budget Office. Editorial assistance was provided by

Patricia Johnston. In accordance with CBO's mandate to provide

objective analysis, this paper offers no recommendations.

Alice M. Rivlin

Director

January 1978

111

IT I MIT

CONTENTS

PREFACE iii

SUMMARY xi

CHAPTER I. INTRODUCTION 1

CHAPTER II. COUNTERFORCE STRATEGIES 5

CHAPTER III. U.S. STRATEGIC VULNERABILITY 9

U.S. ICBM Vulnerability 9

U.S. Bomber Vulnerability 22

The Submarine-Based Force 24

The Vulnerability of the TRIAD 27

CHAPTER IV. U.S. COUNTERFORCE CAPABILITY 31

Deterrence and Strategic Stability 31

Silo-Based Counterforce Capability 35

Mobile-Based Counterforce Capability 38

CHAPTER V. U.S. OPTIONS 45

Finite Deterrence 45

Slow Counterforce 46

Prompt Counterforce ... 50

APPENDIX A. THE SNAPPER FORCE EXCHANGE MODEL 57

APPENDIX B. U.S. ICBM VULNERABILITY IN THE MID-1980S ... 59

APPENDIX C. U.S. ICBM VULNERABILITY IN THE

MID-TO-LATE 1980s 67

APPENDIX D. GLOSSARY 75

HI
.JUBIlilL
TABLES

TABLE 1. ESTIMATED SOVIET STRATEGIC NUCLEAR FORCES, 1985 . 16

TABLE 2. ESTIMATED U.S. STRATEGIC NUCLEAR FORCES 18

TABLE 3. U.S. STRATEGIC FORCES SURVIVING A FIRST STRIKE . 30

TABLE 4. SOVIET ICBMs SURVIVING A U.S. FIRST STRIKE ... 34

TABLE 5. TOTAL SURVIVING SOVIET AND U.S. ICBMs AFTER

SOVIET FIRST STRIKE AND U.S. SECOND STRIKE ... 37

TABLE 6. COSTS OF FORCES FOR FINITE DETERRENCE 47

TABLE 7. COSTS OF FORCES FOR SLOW COUNTERFORCE 49

TABLE 8. COSTS OF FORCES FOR PROMPT COUNTERFORCE 52

TABLE 9. SUMMARY OF COSTS OF THREE OPTIONS 54

APPENDIX TABLES

TABLE B-l. ATTACK 1: ONE GRDUNDBURST 60

TABLE B-2. ATTACK 2: ONE AIRBURST, ONE GROUNDBURST .... 62

TABLE B-3. ATTACK 3: ONE AIRBURST, ONE GROUNDBURST

AND REPROGRAMMING FOR RELIABILITY 64

TABLE C-l. ATTACK 1: ONE GROUNDBURST 68

TABLE C-2. ATTACK 2: ONE AIRBURST, ONE GROUNDBURST .... 70

TABLE C-3. ATTACK 3: ONE AIRBURST, ONE GROUNDBURST

AND REPROGRAMMING FOR RELIABILITY 72

VI l

I II If ! 1
ill!
FIGURES

FIGURE B-l. SURVIVING U.S. MINUTEMAN FORCE: 90 PERCENT

CONFIDENCE INTERVALS FOR ATTACK 1 61

FIGURE B-2. SURVIVING U.S. MINUTEMAN FORCE: 90 PERCENT

CONFIDENCE INTERVALS FOR ATTACK 2 63

FIGURE B-3. SURVIVING U.S. MINUTEMAN FORCE: 90 PERCENT

CONFIDENCE INTERVALS FOR ATTACK 3 65

FIGURE C-l. SURVIVING U.S. MINUTEMAN FORCE: 90 PERCENT

CONFIDENCE INTERVALS FOR ATTACK 1 69

FIGURE C-2. SURVIVING U.S. MINUTEMAN FORCE: 90 PERCENT

CONFIDENCE INTERVALS FOR ATTACK 2 71

FIGURE C-3. SURVIVING U.S. MINUTEMAN FORCE: 90 PERCENT

CONFIDENCE INTERVALS FOR ATTACK 3 73

IX

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SUMMARY

U.S. strategic nuclear forces consist of three parts: landbased intercontinental ballistic missiles (ICBMs), long-range

bombers, and submarine-launched ballistic missiles (SLBMs).

Together these three parts are known as the TRIAD.

These forces are an important part of perceived U.S. military

power, and as such serve a variety of political and military

functions; chief among these functions is that of deterring a

Soviet nuclear attack. To deter such an attack, U.S. forces must

be capable of surviving a Soviet nuclear attack against them

(usually referred to as a "counterforce" attack) in sufficient

numbers to threaten retaliation that would be unacceptable to the

Soviet Union.

In recent years, concern has grown that one element of the

U.S. TRIAD, land-based ICBMs, might become vulnerable to a first

strike by a Soviet ICBM force consisting of increasingly accurate

missiles armed with Multiple Independently Targetable Reentry

Vehicles (MIRVs). Although current and programmed U.S. forces

will continue to provide a capability to destroy Soviet urban

industrial centers in a second strike, additional nuclear weapons

might be required for deterrence of a Soviet counterforce strike,

since a U.S. threat to destroy Soviet cities might not be credible

as long as U.S. cities remained intact and the Soviet Union

retained forces capable of destroying them. Some analysts

argue that unless U.S. strategic forces were capable of retaliating against the Soviet ICBMs remaining after a first strike

against the United States, the Soviet Union might be able to gain

an advantage by destroying the U.S. land-based missile force.

The need for several programs to modernize and augment U.S.

strategic forces will depend upon judgments made about the desirability of developing a second-strike counterforce capability.

These judgments will affect decisions about such weapon programs

as the following:

o Development and procurement of the MX missile, a more

powerful, more accurate, and potentially mobile ICBM;

o Development and procurement of the Trident II missile, a

more powerful, more accurate submarine-launched missile;

XI
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o The ultimate size of the Trident submarine fleet and the

pace of submarine construction; and

o The number of bomber-launched cruise missiles and cruise

missile carriers.

U.S. Strategic Vulnerability

A successful counterforce attack on land-based ICBMs in

hardened underground silos would require a force of MIRVed missiles with high accuracy and warhead yield. Many observers have

expressed concern that the large-scale deployment of the new

generation of MIRVed Soviet ICBMs (the four-warhead SS-17, the

eight-warhead SS-18, and the six-warhead SS-19) may pose a significant threat to the U.S. ICBM force. This modernization

program will apparently not be significantly constrained by a

SALT II agreement.

The 6,000 to 7,000 independently targetable warheads that may

eventually be in the Soviet ICBM arsenal would not, however, all

be useful in a simultaneous attack on U.S. land-based missiles.

An important attack constraint results from the effects of nuclear

detonations on warheads entering an area where previous explosions

have taken place, a phenomenon known as fratricide. This phenomenon would probably limit an attacker to one or two explosions

per target. As a result, the current generation of Soviet MIFVed

ICBMs, if their accuracy proves to be no better than 1,500 to

1,200 feet, could probably destroy no more than about 40 to 60

percent of the U.S. land-based missile force. Furthermore,

even damage of this magnitude would be a risky prospect for an

attacker, since a great deal of uncertainty surrounds estimates

of missile reliability and accuracy, warhead yield, and silo

resistance to nuclear effects. These uncertainties together raise

the possibility that a Soviet counterforce attack would leave many

more U.S. missiles surviving than anticipated.

If the Soviets are to enhance their counterforce capability,

they must improve the accuracy of their missiles. Reports have

indicated that the Soviets have yet another generation of ICBMs

under development, presumably being designed for improved accuracy. Preventing the development and deployment of more accurate,

multiple-warhead Soviet ICBMs will be an important task for future

arms limitation negotiations. If new missiles capable of accuracies of about 600 feet were developed and deployed, then by the

mid-to-late 1980s, over 90 percent of the U.S. ICBM force might be

vulnerable to a Soviet attack that allocated two warheads to each

silo. A Soviet leadership could not, however, count on damage

of this magnitude, since there would be a 5 percent chance that

XI1
only 75 percent would be destroyed, leaving 250 U.S. ICBMs remaining after a counterforce attack rather than 100.

In any case, ICBMs are only one part of the U.S. nuclear

arsenal. In fact, about half of the equivalent megatonnage in the

U.S. force, a measure of area destructive power, is carried by

long-range bombers, while half of the warheads, a measure of the

ability to attack large numbers of targets, are carried by submarine-launched ballistic missiles. Since alert bombers and submarines at sea will probably maintain their survivability and their

ability to penetrate enemy air defenses into the foreseeable

future, even a successful Soviet attack on U.S. ICBMs would not

compromise the ability of the United States to inflict devastating

retaliation on the Soviet Union.

U.S. Counterforce Capability

The threat to retaliate against Soviet cities might not deter

a Soviet counterforce attack, since the United States would be

reluctant to attack Soviet cities as long as U.S. cities remained

intact and the Soviet Union maintained reserve forces capable of

destroying them. For this reason, the United States might desire

an ability to carry out a counterattack against Soviet ICBMs to

deter a Soviet counterforce strike. If U.S. forces that survived

a Soviet first strike were capable of destroying most of the

Soviet ICBMs held in reserve, then no possible gain would result

from a Soviet attack, and deterrence might be enhanced.

There are several objections to any U.S. attempt to buy

forces designed to fight counterforce wars. First, even with the

complete loss of the ICBM force, the United States would still

have enough weapons for counterattacks on Soviet conventional

military targets or isolated economic assets, in addition to those

needed for attacks on Soviet cities.

Most importantly, a U.S. second-strike counterforce capability might be indistinguishable to the Soviet Union from a

first-strike force. Because of their relatively greater dependence on ICBMs, the Soviets might be particularly sensitive

to a U.S. counterforce threat. As a result, a Soviet leadership

facing a serious international crisis might feel strong incentives

to launch a preemptive strike against U.S. strategic forces before

their own land-based missiles could be destroyed.

A threat to the Soviet ICBM force might compel the Soviet

Union to build new weapons to compensate for the vulnerability of

their silo-based missiles. Thus, a new round of U.S. arms producXlll
tion might reduce, rather than enhance, U.S. security. Proponents

of a U.S. counterforce capability suggest that the Soviet arms

buildup is already threatening strategic stability and that a

threat to the survivability of Soviet ICBMs would force the Soviet

Union either to negotiate an agreement limiting the counterforce

threat or to reduce their reliance on silo-based missiles and

shift to a more survivable basing system. In either case, the

survivability of land-based missiles would be enhanced and incentives to strike first would be reduced.

If a second-strike counterforce capability were desired, the

United States would require additional and more sophisticated

weapons. Silo-based weapons, such as the existing Minuteman

force, are becoming increasingly vulnerable to attack, and, in any

case, could not destroy more than about 40 to 60 percent of the

Soviet ICBM force even in a first strike. Even a U.S. weapon as

formidable as the MX missile, if based in vulnerable Minuteman

silos, would lose its ability to counterattack effectively against

Soviet reserve ICBMs as the Soviets improve the accuracy and

counterforce capability of their own forces. Moreover, silo-based

deployment of a weapon as theatening as the MX missile would

destabilize the nuclear balance, since in a crisis the Soviets

might have a strong incentive to try to knock out a U.S. force

that could destroy over 90 percent of Soviet ICBMs if the United

States were allowed to shoot first.

Mobile weapons would be able to survive a Soviet first strike

against them and could therefore be effective in a second strike.

Mobile counterforce weapons include MX missiles that could move at

random in ten- to twelve-mile long underground trenches or among

several protective above-ground shelters, Trident II submarinelaunched missiles, and bomber-launched cruise missiles. These

weapons have different implications for strategic stability than

do silo-based forces. Since Soviet forces could probably not

destroy them in a preemptive attack, the Soviet Union would have

less incentive to launch a first strike. Thus, crisis stability

might not be jeopardized by deployment of mobile-based U.S.

counterforce weapons.

Arms control might be complicated by the introduction of a

mobile-based counterforce weapon such as MX. Such a weapon would

be more difficult to count than silo-based missiles, and thus

enforcement of arms control agreements might be more difficult.

Proponents of U.S. counterforce capability have argued that even

mobile weapons could be counted at "choke-points" through which

all deployed missiles would have to pass, such as the entrances to

underground tunnels. Moreover, they argue that a U.S. missile

system threatening to Soviet silo-based ICBMs would probably force

the Soviet Union to move to a mobile missile-basing system of

xiv
their own, thus reestablishing a stable situation in which it

would not pay for either side to attack the forces of the other.

Opponents of weapon systems such as MX suggest that it would be

better to avoid such an expensive solution to the ICBM vulnerability problem by reaching arms control agreements that limit the

counterforce threat. For example, strict limits on missile

flight tests or on the number of ICBMs that could be armed with

multiple warheads might prevent both sides from developing an

ability to attack each other's land-based missiles. There is

disagreement, however, over whether or not the prospect of MX

deployment would contribute to the negotiation of such an agreement, since many believe that ongoing U.S. arms programs provide

bargaining leverage, while others argue that U.S. restraint would

better contribute to the negotiating process.

It might be better to develop a new mobile ICBM only to

improve survivability and not to enhance U.S. counterforce capability. Such a course would seek to avoid the potentially destabilizing aspects of counterforce capability, yet it would

respond to the growing vulnerability of silo-based ICBMs. Counterforce proponents argue that the counterforce potential of the

MX missile would be desirable since the United States might want

to be able to retaliate against Soviet ICBMs remaining after an

attack on vulnerable U.S. forces, such as silo-based missiles

and nonalert bombers and in-port submarines.

One way to develop a U.S. second-strike counterforce capability without posing a first-strike threat to the Soviet Union

might be to rely on accurate cruise missiles to counterattack

against Soviet ICBMs. Since these weapons would take several

hours to reach their targets, they would probably not be seen as

first-strike weapons. Because of their accuracy, cruise missiles

would be very effective against hardened Soviet ICBM silos. There

may, however, be a possibility of developing air defenses against

cruise missiles, although the Department of Defense believes that

U.S. cruise missile technology will stay ahead of Soviet defensive

technology. Furthermore, there remains some uncertainty about

cruise missile accuracy and reliability since this weapon is still

in development.

U.S. Options

Finite Deterrence. A policy of finite deterrence would rely

upon a well-hedged threat to retaliate against Soviet cities to

deter nuclear attacks by the Soviet Union, including strikes

against U.S. strategic forces. In practice, the United States

xv

1T1
would have enough weapons for other forms of retaliation, such as

attacks on Soviet conventional military targets. Under a policy

of finite deterrence, the United States could procure Trident I

missiles, about 20 Trident submarines, and about 3,000 cruise

missiles for the B-52 force. New counterforce weapons such as MX

ICBMs, Trident II SLBMs, and large numbers of bomber-launched

cruise missiles would not be required under this policy. A force

for finite deterrence would cost about $111.2 billion (in fiscal

year 1978 dollars) for investment and operating from fiscal years

1979 to 2000.

Slow Counterforce. Under a policy of slow counterforce, the

United States would add to its base force of Trident submarines

and missiles, B-52 bombers, and Minuteman ICBMs enough cruise

missiles and cruise missile carriers for a counterattack against

Soviet ICBMs. Because bombers would take several hours to reach

the Soviet Union, such a force would provide an ability to carry

out a second-strike counterforce attack without posing a firststrike threat to Soviet land-based strategic forces. During the

period between fiscal years 1979 and 2000, a policy of slow

counterforce would add $14.3 billion (in fiscal year 1978 dollars)

to the base force cost of $111.2 billion, for a total cost

of $125.5 billion.

Prompt Counterforce. A policy of prompt counterforce would

call for the procurement of mobile MX ICBMs and/or Trident II

SLBMs. These weapons would provide a capability to retaliate

against Soviet ICBMs within minutes of a Soviet first strike.

Procurement of the MX missile system could also enhance the

survivability of the land-based force and thus maintain a viable

TRIAD. Such a policy would reflect a judgment that a mobile

missile system threatening to the Soviet ICBM force would be

stabilizing rather than destabilizing, because mobile missiles

would be invulnerable to a Soviet preemptive strike and because

they would provide a means to respond to, and thus deter, a Soviet

counterforce attack.

During the period between fiscal years 1979 and 2000, procurement of the MX system would add $25.2 billion (in fiscal year

1978 dollars) to the costs of the strategic forces, for a total

cost of $136.4 billion. A sea-based counterforce capability would

require the procurement of 768 Trident II missiles and 12 extra

Trident submarines at a cost of $28.7 billion (in fiscal year 1978

dollars), for a total cost of $139.9 billion.

The following table summarizes the costs of the three options.

xvi
SUMMARY OF COSTS OF THREE OPTIONS: BY FISCAL YEARS

(In Millions of Current Dollars)

1979 1980 1981 1982 1983

(In Millions of

FY 1978 Dollars)

1979 through 2000

Finite

Deterrence 7,120 8,530 9,110 9,600 10,210 111,200

Slow

Counterforce

Prompt

Counterforce

Trident II

Option

7,120 8,530 9,110 9,600 10,210

MX Option 7,330 9,130 10,340 11,430 11,910

7,230 8,410 9,750 11,790 13,020

125,500

136,400

139,900

NOTE: Costs shown do not include all the costs of maintaining the strategic

forces. Wot included are the costs of such functions as command,

control, and communications; surveillance; and strategic defense; and

the costs of nuclear warheads.

XV11

20-694 0-78- 2
II
CHAPTER I. INTRODUCTION

U.S. strategic nuclear forces are charged with the mission

of deterring a Soviet nuclear attack on the United States. I/

Since defenses against a nuclear attack are both difficult and

limited by the Anti-Ballistic Missile Treaty between the United

States and the Soviet Union, the United States relies upon the

ability of its strategic forces to carry out a devastating retaliatory strike against Soviet cities to deter a Soviet attack. U.S.

forces are designed to be capable of carrying out this "assured

destruction" mission after having absorbed a well-coordinated

surprise Soviet strike against them.

In order to hedge against the failure or destruction of

one part of its nuclear force, the United States maintains a mixed

force of long-range bombers, land-based intercontinental ballistic

missiles (ICBMs), and submarine-launched ballistic missiles

(SLBMs), known collectively as the TRIAD. By diversifying the

force among three parts, each of which has different vulnerabilities, a Soviet nuclear attack on U.S. strategic forces, usually

referred to as a "counterforce" attack, is made more difficult.

In recent years, however, concern has grown that one element

of the U.S. strategic TRIAD, land-based ICBMs, may become vulnerable to a disarming first strike by an increasingly capable

Soviet force. Using a fraction of their ICBM force, the postulated Soviet attack would destroy large portions of U.S.

missiles in their hardened silos. Simultaneous attacks on U.S.

Strategic Air Command (SAC) bases and submarine ports would

destroy bombers not on alert and missile-carrying nuclear submarines (SSBNs) not at sea. At the same time, the existence of a

large Soviet reserve force capable of destroying U.S. cities would

deter a U.S. counterstrike against Soviet cities and thus leave

U.S. leaders with few attractive retaliatory options.

I/ In principle the strategic nuclear forces are also designed to

deter attacks by other countries, but for the foreseeable

future the need to deter attack by other countries will

not significantly increase U.S. force requirements.

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Considerable controversy has surrounded both the issue

of U.S. vulnerability to a Soviet counterforce attack and the

question of what the Soviets might hope to gain from such an

attack. Many observers believe that the United States faces a

significant, and growing, Soviet counterforce threat and that a

deterrence doctrine that relies upon retaliation against Soviet

cities would provide American leaders with few credible responses

to such an attack. They believe that to deter a Soviet counterforce attack U.S. strategic forces must be able to carry out a

counterattack against the Soviet ICBM force, since the threat to

retaliate against Soviet cities might not be credible as long as

U.S. cities remain intact.

On the other side are critics of any U.S. attempt to plan

and build forces for counterforce wars, those confined to each

side's nuclear forces. These critics believe that a Soviet

nuclear attack confined to strikes against U.S. strategic forces

would inflict so much damage on U.S. cities and population that

the United States would be expected to respond with its surviving

SLBMs and alert bombers and that this expectation should deter any

but the most desperate Soviet leadership from attempting such a

strike. Furthermore, many believe that U.S. preparations to fight

counterforce battles only make nuclear war more likely to occur

because U.S. weapons capable of counterattacking against Soviet

ICBMs might appear to pose a first-strike threat to Soviet strategic forces and thus cause a Soviet leadership facing a serious

international crisis to launch a preemptive attack.

Over the next several years the Congress will face a number

of important force procurement issues that depend critically

on judgments about the degree and signficance of U.S. strategic

vulnerability to Soviet counterforce capability and the proper

response to such a development. By the mid-1980s, when U.S.

silo-based missiles will probably become increasingly vulnerable

to Soviet attack, Trident nuclear submarines and Trident I submarine-launched missiles will be entering the force, and cruise

missiles will be deployed on B-52 bombers. Although these systems will probably be sufficient for retaliation against Soviet

industry, leadership targets, and general purpose military

forces, 2/ many analysts have expressed concern about the pos-

_2/ For an examination of the second-strike capabilities of

U.S. forces against Soviet industry and general purpose

military forces, see the forthcoming companion paper on

retaliatory issues.
sibility that improved Soviet ICBMs will enable the Soviet Union

to launch a counterforce strike against U.S. silo-based ICBMs,

while the United States could not respond in kind. If the Congress wishes to maintain strategic forces capable of carrying out

a second-strike counterforce attack against Soviet ICBMs, the procurement of new and more sophisticated weapons would be required.

Judgments about the significance of Soviet counterforce

capability and the need for a similar U.S. capability will, to a

great extent, determine the pace of development and magnitude of

procurement of MX mobile missiles, Trident submarines, Trident II

missiles, cruise missiles, and cruise missile carriers beyond

the existing B-52 force.

The MX missile, a more accurate, more powerful, and potentially mobile ICBM now in the research and development (R&D)

stage and available for deployment by the mid-1980s, will provide

a future option to reduce the vulnerability of land-based missiles, and at the same time substantially upgrade the counterforce

potential of the U.S. nuclear arsenal.

The large missile tubes of the Trident submarines now under

construction will be capable of housing a larger and more accurate

Trident II missile. This missile, which could be developed by the

mid-to-late 1980s, offers an alternative means of developing a

capability to attack Soviet ICBM silos in a second strike.

Since the assignment of submarine-launched missiles to the counterforce role would, however, require the procurement of additional submarines beyond those needed for retaliation against

Soviet cities, the present Trident building rate of three submarines every two years would have to be accelerated in the near

future.

The U.S. cruise missile, guided to its target by a terrainmatching guidance system that is asserted to be extremely accurate, will provide another means to enhance the counterforce

capability of U.S. strategic forces. If the Congress decides to

procure extra cruise missiles for the counterforce task, additional carriers, such as wide-bodied aircraft, would be required.

Decisions about these programs to augment and modernize

U.S. strategic nuclear forces in the mid-to-late 1980s will depend

upon several basic questions:

o Under what circumstances might the Soviets be tempted to

strike one vulnerable element of the U.S. TRIAD, knowing

that a large retaliatory force would survive?
1_JILI1MML

o Should the United States develop the capability to

retaliate against Soviet ICBMs?

o Is the best response to increasing ICBM vulnerability

a shift to more survivable basing systems or the development of a similar threat to Soviet ICBMs?

o How might the Soviet Union react to a threat to their

ICBMs, and would this reaction be desirable or undesirable?

Chapter III of this study examines the projected vulnerability of U.S. strategic forces, especially the ICBM portion of

those forces. Chapter IV deals with the arguments for and against

the development of U.S. counterforce capability.

Before examining the issues of U.S. strategic vulnerability

and counterforce capability, however, it is useful to consider the

question of Soviet motives in launching a counterforce attack.

Only in this context is it possible to develop general criteria

for judging the success or failure of a given Soviet strategy and

what may be required to deter it.
CHAPTER II. COUNTERFORCE STRATEGIES

In any discussion of counterforce exchanges it should always

be remembered that a major nuclear war would be a catastrophe of

unprecedented proportions; starting or risking such a war would be

a desperate act undertaken only under great stress and in the

face of a perceived threat to very important values. Even a war

confined strictly to attacks on nuclear forces would likely cause

millions of deaths and great damage and disruption on both sides.

In addition, neither side could be certain that a limited nuclear

exchange would remain limited and not eventually escalate to

all-out attacks that would cause the deaths of tens of millions.

In fact, it is difficult to imagine the circumstances in which

initiating a nuclear war would be the least miserable option

facing national leaders. Precisely because a nuclear war would be

such a catastrophe, however, prudence demands that the factors

that might contribute to its occurrence be carefully considered.

In general, there are at least three Soviet counterforce

strategies that have been postulated. They are:

o An attack on the U.S. ICBM force designed to reduce

U.S. options in a limited nuclear war.

o An attack on U.S. strategic forces designed to shift

decisively the balance of nuclear power in favor of the

Soviet Union.

o An attack on U.S. strategic forces designed to limit

damage to the Soviet Union in an all-out nuclear war.

In recent years the Department of Defense (DoD) has concentrated on the first of these strategies, expressing concern that a

successful Soviet counterforce strike against land-based missiles

would endanger the ability of the United States to execute flexible options short of all-out retaliation. The superior accuracy

and command and control capability inherent in a land-based

system, capabilities that might be important for strikes against

Soviet military forces involved in a war in Europe or other

1 1
Ill

areas of U.S. treaty commitments, would be lost in such an

event. I/ Leaving aside the controversy surrounding the issue of

limited nuclear options and the desirability of maintaining forces

designed for such contingencies, there are several questions that

can be raised about the scenario postulated by the Defense Department.

For one thing, it is unclear that the United States would

remain interested in the execution of flexible and controlled

responses after having absorbed a large-scale nuclear attack on

U.S. ICBMs that killed millions of Americans. In any case, given

the existence of thousands of nuclear weapons in surviving ICBMs,

bombers, and submarines, as well as tactical missiles and aircraft, the United States would retain many retaliatory options,

since surviving forces would be capable of carrying out strikes

against Soviet conventional forces or important isolated economic

targets. Many analysts believe, however, that U.S. forces should

be capable of carrying out a counterattack against Soviet ICBM

silos. A requirement that U.S. strategic forces be able to

perform such a second-strike counterforce mission might call for

the procurement of additional, and more sophisticated, U.S.

nuclear weapons.

Others have suggested that the Soviet Union might be motivated to strike U.S. strategic forces in order to shift decisively

the balance of power in their favor. A counterforce attack with

this goal in mind would be designed to destroy such a large

portion of U.S. forces with such a small expenditure of Soviet

I/ Defense Secretary Schlesinger summarized this concern:

Since both we and the Soviet Union are investing so

much of our capability for flexible and controlled

responses in our ICBM forces, these forces could

become tempting targets, assuming that one or both

sides acquire much more substantial hard-target kill

capabilities than they currently possess. If one

side could remove the other's capability for flexible and controlled responses, he might find ways of

exercising coercion and extracting concessions

without triggering the final holocaust.

(Annual Defense Department Report, FY 1976 and FY 197T,

page I1-4.)
force that the Soviets would gain strategic superiority so massive

that the extreme asymmetry in the destruction that the two sides

could inflict on one another would deter the United States from

using its inferior force in retaliation. In this case, American

leaders might be left with few response options, and U.S. forces

might fail to deter a Soviet first strike. To deter a Soviet

counterforce attack designed to shift the balance of nuclear

power, many analysts believe that the United States must maintain

survivable forces large enough to prevent a massive Soviet advantage in the ability to inflict damage. Others believe that the

U.S. forces should be capable of counterattacking against Soviet

strategic forces remaining after a counterforce strike against the

United States. In this way, the United States might be able to

redress an imbalance of power resulting from a Soviet first

strike.

A third possible Soviet counterforce strategy would involve

attacks on U.S. nuclear forces for the purpose of limiting the

damage that the United States could inflict on the Soviet Union in

an all-out nuclear war. Obviously, a Soviet leadership considering such an attack would have to be convinced that circumstances

were so desperate that nuclear war was imminent. In this case, by

striking first, the Soviets might be able to destroy a large

percentage of the U.S. nuclear force, thus making the outcome of a

nuclear war less catastrophic for the Soviet Union than it otherwise would have been. Deterrence of a damage-limiting strike

requires that U.S. nuclear forces must be able to survive a

Soviet counterforce attack against them and then carry out a

devastating retaliatory attack against Soviet cities. U.S. forces

capable of retaliating against Soviet nuclear forces would not be

required in this case. The survivability of U.S. forces is

examined in Chapter III of this study.

Those who believe that the Soviet Union might be tempted

to attack U.S. strategic forces for the purpose of reducing

American options or shifting the balance of power suggest that

deterrence requires not only forces capable of destroying Soviet

cities but also weapons designed to counterattack against Soviet

nuclear forces. Opponents of such a second-strike counterforce

policy suggest that there is a dilemma involved in the procurement

of U.S. counterforce weapons. They believe that a U.S. force

large enough to retaliate against Soviet nuclear forces in a

second strike would, by definition, pose a significant firststrike threat to the Soviet Union. Furthermore, this threat might

dangerously destabilize the strategic balance and provide an

incentive for a Soviet first strike. Chapter IV focuses on the

question of U.S. second-strike counterforce capability and the

associated doctrine.
...I
CHAPTER III. U.S. STRATEGIC VULNERABILITY

U.S. ICBM VULNERABILITY

In the 1960s, silo-based Intercontinental Ballistic Missiles

(ICBMs) were thought to be essentially invulnerable to a first

strike. In order to destroy such a target, an attacker would have

to fire a missile of his own at each enemy missile site. Since

many of the attacker's missiles would fail to function properly or

miss their targets, it was inevitable that the attacker would use

more weapons than he could possibly destroy. Thus, given roughly

equal forces, an attack under such circumstances would be a

self-disarming act.

In recent years, however, technological advances have

dramatically altered this picture. The crucial event was the

development of Multiple Independently Targetable Reentry Vehicles,

or MIRVs. With missiles that carry more than one warhead, an

attacker can potentially destroy more than one enemy missile

for each one he uses. If the U.S. and Soviet ICBM forces were

constrained to be of roughly equal size, either by arms control

agreements or by cost considerations, then an attacker using

MIRVed missiles might be able to destroy a large part of the other

side's ICBMs while expending only a fraction of his own force.

The United States developed and deployed the first MIRVed

ICBM, the three-warhead Minuteman III missile. In 1975 the Soviet

Union began deployment of its own MIRVed ICBMs, the SS-17, SS-18,

and SS-19. This coupling of traditionally large Soviet missiles

with MIRV technology has been a particularly disquieting event,

because the power of these missiles makes possible the delivery of

large numbers of warheads. The SS-18, for example, can deliver

eight to ten warheads, thus creating the possibility that each

SS-18 might destroy several U.S. silo-based missiles.

Even with the deployment of MIRVed missiles, the actual

vulnerability of ICBM silos to a counterforce strike is determined

by the interaction of several other factors: the hardness of the

target; the accuracy, explosive power, and reliability of the

attacking missile; and the tactics used in the attack. For example, a one megaton warhead, typical of Soviet weapons, delivered

I III! I ']
...Uffllllli JL_

by a reliable missile with circular error probable (CEP) I/ of

1,200 feet (0.2 run) would have less than a 50 percent chance of

destroying a silo hardened to withstand 2,000 pounds per square

inch (psi). If accuracy could be improved to 600 feet (0.1 nm),

the same one megaton weapon would have almost a 90 percent chance

of destroying the same target. A missile accurate to 600 feet

but with warhead yield of only 20 kilotons (equivalent to the bomb

dropped on Hiroshima), however, would have less than a 20 percent

chance of destroying a target hardened to 2,000 pounds per square

inch. Thus, an appropriate combination of accuracy and warhead

yield is needed for an effective counterforce capability.

U.S. missiles are generally believed to be more accurate than

their Soviet counterparts, but in recent years the Soviet Union

has been making great strides in the field of guidance technology.

Since the warhead yields of the current generation of Soviet ICBMs

are already very large, improvements in missile accuracy will be

the major driving force behind growing Soviet counterforce capability.

Uncertainties of Attack Effectiveness

A very significant consideration for attack planning is the

great uncertainty surrounding the actual accuracy of any given

guidance technology. This uncertainty results in part from the

limited number of tests a missile system undergoes to verify its

accuracy potential. Gaining high confidence in estimates of a

missile CEP would require a large number of tests for each missile

and for each change in its guidance system. Such testing is

constrained, however, by the limited resources that can be devoted

to the very expensive task of missile testing. Moreover, actual

operational performance can be degraded by variable atmospheric

conditions and small perturbations in the earth's gravitational

I/ The measure most commonly used to describe the accuracy of a

ballistic missile is known as circular error probable (CEP).

This is the radius, centered about the intended target,

that forms a circle within which 50 percent of the warheads

will land.

10
field. 2/ As a result, actual CEPs can only be estimated within a

fairly large range of uncertainty, and any assessment of the

damage that an attack can be expected to cause must take into

account the uncertainties surrounding these operational accuracies.

Although missile accuracy is perhaps the most important

source of uncertainty about the actual results of a counterforce

attack, similar uncertainty surrounds estimates of warhead yield,

missile and warhead reliability, and silo hardness. Again, much

of this uncertainty results from the limited amount of test data.

In addition to the expense of missile and warhead tests, other

constraints prevent the gathering of complete knowledge about

the performance of weapon systems. For example, treaty restrictions on atmospheric detonations prevent actual testing of silo

hardness. As a result, no one can know for sure how resistant

these shelters will be to the various effects of nuclear detonations .

Fratricide and Counterforce Tactics

The operational performance of weapons is not the only source

of uncertainty about the results of a counterforce attack. In

recent years analysts have come to recognize an additional

attack constraint resulting from the effects of nuclear detonations on warheads entering an area where previous explosions have

taken place. This phenomenon, known as "fratricide," could cause

the destruction of weapons used in a large-scale attack on missile

fields, and it therefore places severe restrictions on counterforce tactics that involve the targeting of more than one warhead

on each silo. In fact, most analysts believe that no more than

two warheads could be exploded in the neighborhood of each enemy

2/ American missiles are typically fired over the Pacific Ocean

at Kwajalein Island in the Marshall Islands. While such tests

may give weapons designers precise knowledge of the gravitational forces that this portion of the earth exerts on ballistic missile flight, they are not necessarily accurate

indicators of how a missile fired over the Arctic at the

Soviet Union would perform. Presumably the Soviet Union faces

similar uncertainty about possible accuracy degradation

because of unpredictable guidance errors of this sort. As a

consequence, an attacker could never be sure that his missiles

would perform in an actual counterforce attack as test data

would lead him to believe.

11

I Illl I
I Illl

missile silo. Even a two-on-one attack would be difficult,

since first-wave warheads would have to be exploded several

hundred feet above the target in order to avoid throwing lethal

ground debris into the air, while second-^wave warheads (targeted

to explode on the ground) would have to enter the area with

split-second timing in order to avoid destruction by the nuclear

effects of first-wave warhead detonations.

It is possible that no more than one warhead could be

successfully exploded over each target. Other nuclear effects,

such as intense heat and dust clouds, could be lethal to subsequent warheads even if first-round weapons were burst above the

surface in order to avoid the throwing of ground debris into the

air. 3/ An attacker who accepted this view would fire two warheads (both programme^ to detonate on ground contact) at each

enemy silo only to insure against the possibility that the first

one proved to be unreliable and either failed to reach the area of

the target or to explode. 4/ If no more than one nuclear warhead

could be exploded in the neighborhood of each target, an attacker

would be better off not to try for two detonations, since such an

attempt requires that less accurate, less destructive airbursts be

used in the attack. 5/

3/ For an unclassified discussion of fratricide, see Joseph J.

McGlinchey and Jakob W. Seelig, "Why ICBMs Can Survive A

Nuclear Attack," Air Force Magazine, September 1974.

4/ More than two warheads could be fired at each silo, but the

small additional probability that at least one warhead would

reach each target would probably not be worth the cost in

terms of expended attacker weapons.

5/ The penalty for an unsuccessful attempt to explode two warheads over each silo can be quantified by examining the case

in which fratricide proves to be unavoidable and first-wave

airburst warheads destroy second-wave groundburst warheads.

Expected damage to the ICBM force in this case would be 44

percent for an attack with SS-18 missiles accurate to 1,200

feet (assuming 20 percent height of burst error for airburst

warheads, and assuming that second-wave groundburst warheads

reach 25 percent of the silos due to first^wave failures).

This 44 percent damage expectancy compares with 54 percent for

the case of two groundbursts (one explosion). The potential

loss of 10 percent damage expectancy compares with a potential

gain of 8 percent if an attempt to explode two warheads over

each silo were successful (see Appendix B).

12
Uncertainties about fratricide will probably never be

settled. For one thing the prohibition on atmospheric testing

prevents real world evaluation of a modern warhead's ability to

withstand the various effects of a nuclear explosion. In light of

the penalties that would be paid for an unsuccessful attempt to

avoid fratricide, an attacker would probably have to make the

conservative assumption that insuring against missile and warhead

unreliability is the best tactic available. On the other hand,

consideration of more ambitious attacks that successfully detonate

two warheads in the area of each target does serve to provide an

upper bound for the damage that a Soviet counterforce strike might

cause. 6/

A third counterforce tactic attempts to program two warheads

to detonate in the neighborhood of each target while at the same

time reprogramming spare missiles to replace those that fail in

the early portions of flight. In a two-on-one attack that attempts to explode two warheads in the area of each target, reprogramming for reliability would be a particularly demanding task,

since the warheads from replacement missiles would have to arrive

on target at the same time as those of the failed missiles in

order to avoid fratricide. For this reason, an attack that could

get two successful explosions in the neighborhood of each target

and reprogram failed missiles is probably the worst scenario that

U.S. missiles could possibly face.

U.S. ICBM Vulnerability in the Mid-1980s

As we have seen, a successful counterforce attack requires a

force of MIRVed ICBMs that combines high accuracy and warhead

yield. Until recently, the Soviet Union did not possess such a

force. The bulk of the Soviet ICBM force consisted of singlewarhead SS-9s and SS-lls that are reportedly capable of accuracies

no better than about one to one-half of a nautical mile. 7/

6/ More than two warheads might be exploded in the area of each

silo if the attacker waited for an hour or more for dust

clouds to dissipate. A delay of this length would, however,

greatly increase the opportunity for the victim to launch his

surviving missiles.

7/ See Thomas J. Downey, "How to Avoid Monad and Disaster,"

Foreign Policy, Fall 1976.

13
I ill •••in: in

By the mid-1980s, the Soviets should complete deployment of a

new generation of MIRVed ICBMs, the SS-17, SS-18, and SS-19 with

four, eight, and six warheads respectively. This modernization

program will apparently not be significantly constrained by a SALT

II treaty, since the Soviets will probably be allowed to replace

all their large SS-9 ICBMs with MIRVed SS-18 missiles and since

very high limits on MIRVed ICBMs will be allowed. 8/ One unclassified estimate of what Soviet strategic forces might look

like by 1985 is presented in Table 1. For comparison, estimates

of the size and structure of U.S. forces are presented in Table 2

for both 1977 and the mid-1980s.

Many observers have expressed concern that a Soviet ICBM

force consisting of thousands of multiple warheads, with the

combination of high yield and improved accuracy shown in Table

1, would pose a significant threat to the U.S. ICBM force. With

the aid of computer missile exchange simulations based on the

estimates presented in Tables 1 and 2, it is possible to examine

in more detail the exact nature of this threat. 9/

An attacker planning a counterforce strike would have an

incentive to program both warheads fired at each enemy missile

silo to detonate on ground contact. Although such a tactic would

probably eliminate any chance to get two detonations in the

neighborhood of each target, it would greatly increase the odds

that every enemy silo would suffer the effects of a nuclear

explosion, and it would avoid the use of less accurate, less

destructive airbursts. A Soviet attack that exploded no more

than one warhead on each target (but fired two), using 264 eightwarhead SS-18s, all accurate to 1,500 feet, against 1,054 U.S.

ICBM silos, 10/ would be expected to destroy about 40 percent

8/ See "Major Concessions By U.S. and Soviet on Arms Reported,"

New York Times, October 11, 1977, p. 1.

9/ The SNAPPER Force Exchange Model developed for the Air Force

by the Rand Corporation has been used to calculate attack

results. For a detailed description of this model see

Appendix A.

10/ Assuming Minuteman silo hardness of 2,000 pounds per square

inch and Titan hardness of 550 pounds per square inch.

See "MX Deployment Urged for Parity," Aviation Week and

Space Technology, December 5, 1977, p. 13.

14
of the land-based missile force. This would leave intact 60

percent of the U.S. ICBM force, consisting of over 600 missiles,

1,200 warheads, and 600 equivalent megatons, ll/ Even if Soviet

missile accuracies could be improved to 1,200 feet, only about 55

percent of U.S. ICBMs would probably be destroyed, leaving 45

percent of the land-based force, or over 450 missiles, 950 warheads, and 450 equivalent megatons. 12/

These results indicate the number of U.S. missiles that can

be expected to survive a Soviet attack, given specific assumptions

about the performance of the weapon systems involved in the

attack. As discussed in previous sections, a great deal of

uncertainty surrounds estimates of these parameters. Therefore,

an attacker would have to consider the degree of confidence that

he could have in the results of an attack, as well as the best

guess about those results. If the values of CEP, warhead yield,

reliability, and target hardness are all allowed to vary within

reasonable limits, the range of results that would bound the

actual, unknown result with 90 percent confidence can be determined. For an attacker concerned about the catastrophic

consequences of failure, a reasonably narrow confidence interval

would obviously be an important consideration in the decision to

attack or not. In the attacks described above, the number of

surviving U.S. ICBMs can vary, with 90 percent confidence, from 70

percent to 45 percent after an attack by Soviet missiles theoretically capable of 1,500-foot accuracies. In other words, there is

a 5 percent chance that 70 percent of the U.S. ICBMs, rather

than 60 percent, would survive the Soviet attack, and a 5 percent

ll/ Equivalent megatonnage is a commonly used measure of the

urban area destructive power of a nuclear weapon that accounts for the fact that area destructive power does not

increase proportionately with increases in yield* It is expressed by the relationship EMT = N multiplied by Y to the

2/3 power, where N is the number of weapons of yield Y.

12/ If the Soviets could succeed in exploding two warheads over

each silo, they could destroy about 50 percent of the U.S.

ICBM force, assuming a 1,500 ft. Soviet CEP. A Soviet

two-on-one attack with missiles accurate to 1,200 feet would

be expected to destroy about 60 percent of U.S. ICBMs. If

two warheads could be exploded over each U.S. silo and early

missile failures could be reprogrammed, damage to the U.S.

ICBM force would be expected to be; 55 percent, assuming a

1,500 ft. Soviet CEP, or slightly less than 70 percent, assuming 1,200 ft. CEP. For detailed results, see Appendix B.

15

20-694 O - 78 - 3

111
TABLE 1. ESTIMATED SOVIET STRATEGIC NUCLEAR FORCES, 1985

Launcher

SS-11

SS-17

SS-18

SS-19

SS-16

Total '

ICBMs

SS-N-6 )

SS-N-8 J

SS-N-17)

SS-N-18J

Total

SLBMs

Bear

Bison

(Backfire)

Total

Bombers

Grand

Total

Warheads Per

Number a/ Launcher b/

330 1

200 4

308 8

500 6

60 1

1,398

600 1

300 3

900

100 1

40 1

(250) (2)

140

(390)

2,438

(2,688)

Total

Warheads

330

800

2,464

3,000

60

6,654

600

900

1,500

100

40

(500)

140

(640)

8,294

(8,794)

Yield in

Megatons

1.5

0.6

1.5

0.8

1.0

1.0

0.2

20

5

(0.2)

Total

c/ Megatons

495

480

3,696

2,400

60

7,131

600

180

780

2,000

200

(100)

2,200

(2,300)

10,111

(10,211)

Circular

Equivalent Error

Megatons Reliability d/ Probable e/

432 0.70 3,000 ft.

560 0.75 1,500 ft.

3,228 0.75 to

2,580 0.75 1,200 ft.

60 0.75

6,860

600 0.70 6,000 ft.

306 0.70 3,000 ft.

906

740

116

(170)

856

(1,026)

8,622

(8,792)

(continued)
a

TABLE l. (Continued)

SOURCES:

a. Number of SS-18s and total number of SS-17s and SS-19s from testimony of General Alton Slay, in Military Posture

and H.R. 11500, Hearings before the House Armed Services Committee, 94:2 (1976), Part 5, p. 288. Ratio of SS-19s to

SS-17s assumed same as at present. Number of MIRVed SLBMs assumes 1,320 MIRVed ballistic missile limit. Numbers

of Bears and Bison from General George S. Brown, United States Military Posture for FY 1978, p. 18. Number of

Backfire assumes annual production of 25 (see International Institute for Strategic Studies (IISS), The Military

Balance, 1977-78 (London: 1977), p. 4.).

Total number of Soviet delivery vehicles shown exceeds any likely SALT II agreement. Given a limit of 2,200 strategic delivery vehicles, the Soviets would have to retire about 200 launchers, probably older SS-11 ICBMs and Bear

and Bison bombers. With a MIRVed ICBM ceiling of 800, 200 fewer SS-17s and SS-19s would probably be deployed.

SS-18 deployment would not necessarily be affected.

b. Number of ICBM warheads from Donald H. Rumsfeld, Annual Defense Department Report, Fiscal Year 1978, p. 62. SLBM

warhead figures from General George S. Brown, United States Military Posture for FY 1978, p. 16. Bomber figures from

Projected Strategic Offensive Weapons Inventories of the U.S. and U.S.S.R., Congressional Research Service, March

24, 1977, p. 85.

c. Warhead yields from "MX Deployment Urged for Parity," Aviation Week and Space Technology, December 5, 1977, pp.

14-15, and Jane's Weapon Systems, 1977, pp. 10-12. Bomb yields from Projected Strategic Offensive Weapons Inventories of the U.S. and USSR, p. 95.

d. Obtaining missile reliability greater than 80 percent is believed to be a very difficult task (see Albert C. Hall,

"The Case for an Improved ICBM," Astronautics and Aeronautics, February 1977, p. 29). Soviet missiles are generally

considered to be less reliable than their U.S. counterparts.

e. Although official estimates of Soviet missile accuracies are classified, various public sources provide an unclassified consensus estimate of 1,500 ft. (0.25 nm) CEP for the new generation of Soviet ICBMs. See "U.S. Missiles Seen

Vulnerable by Early 1980s," Washington Post, September 18, 1977, p. A6. In addition, one official statement adds

credence to this estimate. In an appearance before the Senate Foreign Relations Committee in 1974, Secretary of

Defense James Schlesinger testified: "We have some information that the Soviets have achieved, or will soon achieve,

accuracies of 500 to 700 meters with their ICBMs. These figures may be a little optimistic, but that would represent

about a fourth to a third of a nautical mile." (Briefing on Counterforce Attacks, Hearing before the Subcommittee on

Arms Control, International Organizations and Security Agreements of the Senate Foreign Relations Committee, 94:1

(September 11, 1974), p. 10.) In addition, defense officials have alluded to the possibility of further improvements

in accuracy with continued testing of the current generation of missiles. (See Department of Defense Authorization,

Fiscal Year 1978, Hearings before the Senate Armed Services Conroittee, 95:1 (April 1977), Part 10, p. 6869.) Therefore, accuracy upgrade to 1,200 ft. (0.2 nm) is also considered. See "MX Deployment Urged for Parity," Aviation Week

and Space Technology, December 5, 1977, pp. 14-15.
TABLE 2. ESTIMATED U.S. STRATEGIC NUCLEAR FORCES

Minuteman II

Minuteman III

Titan II

Total ICBMs

(Present Force)

Launcher

Warheads

Number per Launcher

Total

Warheads

Yield in

Megatons

Total

Megatons

Equivalent

Megatons Reliability

Circular

Error

Probable

450

550

54

1,054

450

1,650

54

2,154

1.0

0.17

9.0

450.0

280.5

486.0

1,216.5

450

512

232

1,194

0.80

0.80

0.75

1,800 ft.

700 ft.

3,000 ft.

Polaris

Poseidon

Total SLBMs

B-52 G/H

B-52D

FB-111

Total Bombers

Grand Total

160

496

656

255

75

60

390

2,100

1

10

(4 SRAM

(4 Bombs

4 Bombs

(2 SRAM

(2 Bombs

160

4,960

5,120

1,020

1,020

300

120

120

2,580

9,854

0.6

0.04

0.2

1.0

1.0

0.2

1.0

96

198

294

204

1,020

300

24

120

1,668

3,178.5

163 0.80 3,000 ft.

595 0.80 1,500 ft.

758

347

1,020

300

41

120

1,828

3,780

SOURCES: There is fairly wide agreement among various unclassified estimates of U.S. nuclear forces. For ICBM and SLBM

figures, see Thomas J. Downey, "How to Avoid Monad and Disaster," Foreign Policy, Fall 1976; Statement of

the Honorable Robert L. Leggett, Vladivostok Accord; Implications to U.S. Security, Arms Control, and World

Peace, Hearings before the Subcommittee on International Security of the House Committee on International

Relations, 94:1 (June-July 1975), pp. 8-14; and Kosta Tsipis, "The Accuracy of Strategic Missiles," Scientific

American, July 1975, p. 190. Minuteman III CEP of 700 ft. (see "U.S. Plans 'Cold-Launch1 ICBMs," Aviation Week

and Space Technology, February 4, 1974, p. 14) assumes the more accurate MK-12A warhead not yet deployed. For

bomber estimates, see Archie L. Wood, "Modernizing the Strategic Bomber Force Without Really Trying—A Case

Against the B-l," International Security, Fall 1976, and Alton H. Quanbeck and Archie L. Wood, Modernizing the

Strategic Bomber Force (The Brookings Institution, 1976), p. 36.

(continued)
TABLE 2. (Continued)

(Mid-1980s Force)

—1

E

Launcher

Minuteman II

Minuteman III

(with MK-12A)

Titan II

Total ICBMs

Poseidon

Poseidon C-4

Trident I

Total SLBMs

B-52 G/H

B-52CM

FB-111

Total Bombers

Grand Total

Number

450

550

(550)

54

1,054

336

160

240

736

165

165

60

390

2,180

Warheads Total

per Launcher Warheads

(6

' 4

20

(2

(2

1

3

(3)

1

10

8

8

SRAM

Bombs

ALCM

SRAM

Bombs

1

(1

2

3

1

1

6

3

5

13

450

,650

,650)

54

,154

,360

,280

,920

,560

990

660

,300

120

120

,190

,904

Yield in

Megatons

1.

0.

(0.

9.

0.

0.

0.

0.

T

_L •

0.

0.

1.

0

17

35)

0

04

10

10

2

f~\

\J

2

2

0

Total

Megatons

450.0

280.5

(572.5)

486.0

1,216.5

(1,508.5)

134

128

192

454

198

660

660

24

120

1,662

3,332.5

(3,629.5)

Circular

Equivalent Error

Megatons Reliability Probable

450 0.80 1,800 ft.

512 0.80 700 ft.

(825) (0.80) (600 ft.)

232 0.75 3,000 ft.

1,194

(1,507)

403 0.80 1,500 ft.

282 0.80 1,500 ft.

422 0.80 1,500 ft.

1,107

337

660

1,122 300 ft.

41

120

2,280

4,581

(4,894)

SOURCES: MK-12A yield from "Cruise Missile Halt Considered," Aviation Week and Space Technology, May 23, 1977, p. 19.

Lower Minuteman III CEP assumes that MK-12A warhead is more accurate than older MK-12 warhead. Trident I

missile estimates from "New Propellent Evaluated for Trident Second Stage," Aviation Week and Space Technology, October 13, 1975, p. 15. Cruise missile yield from "ICBM, Guidance Curbs Alarm Planners," Aviation

Week and Space Technology, July 11, 1977, p. 17. Cruise Missile CEP from Kosta Tsipis, "Cruise Missiles,"

Scientific American, February 1977, p. 29. Cruise missiles assumed carried by 75 B-52Ds and 90 B-52Gs.
L

chance that only 45 percent would survive. If Soviet missiles

were theoretically accurate to 1,200 feet, there would be a 5

percent chance that 60 percent of the U.S. ICBM force, rather than

45 percent, would survive, and a 5 percent chance that only 30

percent would survive. 13/

Unless the Soviet Union can make dramatic improvements in its

missile accuracies, it would appear that the generation of MlRVed

ICBMs now being deployed could not deliver a decisive blow to the

U.S. Minuteman force. Even if missile accuracy could be improved

to 1,200 feet, the Soviets could probably destroy no more than 40

to 60 percent of the U.S. ICBM force. In addition, damage of this

magnitude would be a risky prospect, since the operational

performance of weapon systems is subject to many uncertainties.

U.S. ICBM Vulnerability in the Mid-to-Late-1980s

It has been repsrted that the Soviet Union is developing

four new ICBMs. 14/ These missiles are apparently in the preflight phase of development and should be ready for deployment by

the mid-1980s. 15/ Former Chief of Naval Operations, Elmo R.

Zumwalt, has reported that component testing of these missiles has

been observed. 16/ This would place their development at about

the same stage as that of the U.S. MX missile.

Although little information about the characteristics of

these new missiles is available in the public record, it is

believed that improved accuracy is a primary Soviet goal. Therefore, as an approximation of the future threat to U.S. land-based

missiles, it is useful to examine the case of a Soviet attack

13/ See Appendix B for attack outcome variations.

14/ See speech of Secretary of Defense Harold Brown before

the National Security Industrial Association, reported in

"Brown Sees Buildup by Soviets in Missiles," New York Times,

September 16, 1977, p. 9.

15/ Department of Defense Authorization, Fiscal Year 1978,

Hearings before the Senate Armed Services Commitee, 95:1

(1977), Part 10, pp. 6859-60.

16/ Elmo R. Zumwalt, "An Assessment of the Bomber-Cruise Missile

Controversy," International Security, Summer 1977.

20
using a missile similar in payload and yield to the SS-18 but

capable of accuracies of 900 to 600 feet (0.15 to 0.10 nm). IT/

With accuracies as good as those assumed for the next generation of Soviet missiles, the ability to avoid fratricide and

explode two warheads in the area of each target becomes insignificant since single detonations would produce high damage probabilities. With extremely accurate missiles, second warheads would

need to be fired only to improve the odds that each enemy missile

silo would come under attack by at least one weapon. For example,

a Soviet attack using missiles accurate to 600 feet that programs

two groundbursts (one explosion) per target in order to insure

against missile and warhead unreliability would be expected to

destroy over 90 percent of the U.S. ICBM force, leaving a landbased force of less than 100 missiles, 200 warheads, and 100

equivalent megatons. 18/

Although an attack that plans for only one explosion per

target is a much less risky tactic, unpredictable variations in

the performance of weapon systems can still result in a range of

attack outcomes. In fact, for the case of cin attack with missiles

theoretically capable of accuracies of 600 feet, the range of

outcomes can vary, with 90 percent confidence, from 25 percent to

5 percent surviving U.S. ICBMs. Thus, the Soviet leadership would

have to consider the prospect that there would be a 5 percent

chance that 250, rather than 100, U.S. ICBMs would be available

for retaliation.

In short, while an attempt at a disarming strike against

silo-based ICBMs would be clearly a risky and unprofitable strategy with missiles accurate only to 1,2:00 feet or more, an attack

with weapons accurate to 600 feet or less might be able to destroy

over 90 percent of the land-based U.S. strategic deterrent. Even

this latter case is risky, however, because of the range of

uncertainty in the outcomes. In addition, land-based ICBMs are

only one element of the TRIAD, and important retaliatory capabilities would survive in the bomber and submarine forces even

after a highly successful attack on ICBMs. In order to assess

17/ Defense Department officials have stated that the achievement

of "extreme" accuracies must await the next generation of

Soviet ICBMs. See Senate Armed Services Committee, Department of Defense Authorization, Fiscal Year 1978, Part 10, pp.

6860, 6866-67.

18/ For detailed results, see Appendix C.

21

'Finn in
the profitability of a successful counterforce strike against U.S.

ICBMs, it is necessary to examine the vulnerability of the other

two elements of the U.S. TRIAD, submarine-based missiles and

long-range bombers.

U.S. BOMBER VULNERABILITY

Since the United States maintains about half of its equivalent megatonnage in its bomber force, a damage-limiting strike

by the Soviet Union that held out any hope of success would have

to include attacks on U.S. B-52 and FB-111 bombers. An attacker

seeking to minimize the destruction that this force could inflict

would have two separate opportunities to stop U.S. bombers.

First, surprise attacks on Strategic Air Command (SAC) bases might

destroy bombers at or near their bases. Second, air defenses

might try to inflict significant attrition on aircraft before they

could use their weapons.

Prelaunch Vulnerability

There is no doubt that most bombers not on alert at the time

of an SLBM or ICBM attack on their bases could be destroyed.

Although only 30 percent of the U.S. B-52 force is maintained on

ground alert under normal peacetime conditions, in time of crisis

crews could be recalled to their bases and the vast majority of

the force placed on alert. A surprise attack on non-alert bombers

is often used, however, as a conservative assumption in assessing

bomber survivability.

Bombers on alert would be more difficult targets, but many

observers believe there is reason for concern about the survivability of this portion of the force as well. These observers

believe that it might be possible for Soviet submarines to fire

their missiles from positions close to U.S. shores, thereby

destroying a large part of the alert bombers at or near their

bases. Although the survivability of alert bombers is a very

important concern, there are several reasons to question this

scenario.

Most importantly, planning a coordinated attack on U.S.

bomber bases would present an adversary with difficult, perhaps

insurmountable, problems. First, in order to minimize missile

flight time, and th'us warning time, Soviet submarines would have

to station themselves close to U.S. coasts. Such a move would

probably be detected by U.S. antisubmarine warfare (ASW) sensors,

thus providing the United States with warning of an attack. Since

detection of provocative Soviet submarine deployments would enable

22
the United States to put the entire bomber force on alert, an

attempt to launch a surprise attack on alert bombers could be a

counterproductive tactic. Furthermore, since a damage-limiting

strike would probably be considered by the Soviet Union only in a

time of extreme crisis, U.S. forces would almost certainly be in a

high state of readiness at the time of an attack.

Even if U.S. bombers were not in their highest state of

readiness, and even if Soviet submarines could position themselves

for attack without being detected, there are reasons to doubt that

alert aircraft could be destroyed at their bases. Given a bomber

reaction time of about three to six minutes, 19/ alert aircraft

would have more than enough time to escape attacks on their

bases by SLBMs with flight times of ten to fifteen minutes. 2Q/

Missiles flying on fast, depressed trajectories would take about

seven minutes to reach bomber bases, 21/ providing a slim margin

of safety for alert bombers. There is no evidence, however,

that the Soviets have tested SLBMs flown on depressed trajectories. 22/ If such tests were to be carried out at some future

date, there would be greater cause for concern about the prelaunch

survivability of alert bombers, and several corrective measures

to insure the survivability of the bomber force might be called

for. These measures include the dispersal of bombers to a larger

number of bases in the interior of the continental United States

and the maintenance of higher alert rates and a more rapid reaction status for alert aircraft.

19/ See Alton H. Quanbeck and Archie L. Wood, Modernizing

the Strategic Bomber Force (The Brookings Institution,

1976), pp. 46-47; and Francis P. Hoeber, Slow to Take Offense: Bombers, Cruise Missiles, and Prudent Deterrence

(Center for Strategic and International Studies, Georgetown

University, February 1977), pp. 84-85.

20/ Statement of James R. Schlesinger in Briefing on Counterforce

Attacks, Hearings before the Subcommittee on Arms Control,

International Organizations and Security Agreements of the

Senate Committee on Foreign Relations, 94:1 (September 11,

1974), p. 22.

.?1/ Quanbeck and Wood, op. cit., p. 44.

22/ Donald H. Rumsfeld, Annual Defense Department Report, Fiscal

Year 1978, p. 123.

23
LIIIL

Penetration Survivability

Even after bombers have successfully escaped attacks on

their bases, they still face threats to their ability to carry out

their retaliatory mission. The Soviet Union has deployed an

extensive network of air defenses consisting of about 6,500

surveillance radars, 2,540 interceptors, and 10,000 surface-to-air

missile (SAM) launchers. Z3/ Furthermore, it is projected that

these defenses will be further strengthened with the eventual

development of an advanced Soviet air defense system against

low-flying aircraft.

There would be several ways to degrade these defenses in

a nuclear war between the United States and the Soviet Union.

First, surviving U.S. land- and submarine-based missiles might be

used to destroy a large portion of Soviet air defenses before the

arrival of the bomber force. 24/ Second, surviving air defenses

could be attacked by the nuclear-armed Short Range Attack Missiles

(SRAMs) carried by penetrating bombers. Furthermore, even without

these potent nuclear countermeasures, the record of U.S. electronic countermeasures (ECM) used by Americans in Vietnam and

Israelis in the 1973 Middle East war indicates that these measures

can be extremely effective against Soviet air defense systems. 25/

Finally, in the future the U.S. bomber force will include thousands of long-range cruise missiles whose low-level flight and

small size will help them avoid detection and whose large numbers

should be capable of saturating surviving Soviet defenses.

THE SUBMARINE-BASED FORCE

Ballistic missile-launching nuclear-powered submarines

(SSBNs) comprise the third element of the U.S. strategic TRIAD.

Because these submarines carry about half of the warheads in the

U.S arsenal, a measure of the ability to attack large numbers of

targets, their destruction would be an especially important

requirement for a successful Soviet damage-limiting strike.

23/ Ibid., p. 58.

24/ See James R. Schlesinger, Annual Defense Department Report,

FY 1976 and FY 197T, p. 11-20.

Quanbeck and Wood (op. cit.) cite estimates of 3 percent

U.S. attrition in the 1972 bombing raids against North

Vietnam and 1 to 1.5 percent Israeli attrition in the 1973

war. See pp. 64-65.

24
At the present time, U.S. nuclear-powered submarines at

sea are considered essentially invulnerable to Soviet attack.

This belief is based on several factors. First, U.S. submarines

are considered to be extremely quiet, providing little, if any,

chance for Soviet acoustic sensors to detect them in the open

ocean. Second, Soviet antisubmarine warfare capabilities are not

considered particularly sophisticated. Finally, geography is a

distinct disadvantage for the Soviets because they have very

limited access to the open oceans where most U.S. submarines are

expected to operate.

Not only is it likely that current U.S. strategic submarines

will remain highly survivable into the foreseeable future, but

Trident submarines now under construction will be even quieter

than current submarines and will be equipped with the most sophisticated passive sonar equipment available. In fact, Navy

officials have stated that the combination of quieting improvements and advanced sonar equipment will allow Trident submarines

to detect enemy forces before they are themselves detected. 26/

As a result, Soviet antisubmarine warfare forces would have great

difficulty detecting and destroying U.S. submarines.

The key to any effort to attack submarines at sea is largearea ocean surveillance. The Soviets have no such system today.

To hedge against the development of such a system, possibly

satellite-based, the 4,000 nm. range of the new Trident I missile

planned for deployment on Trident submarines as well as ten

Poseidon boats will dramatically expand the ocean area available

for on-station patrol. Moreover, the large Trident submarine

tubes allow for the possibility of a 6,000 nm. range Trident II

missile. Such an expansion of patrol area greatly magnifies the

tasks faced by an enemy seeking to track and destroy a large

number of submarines that are trying to avoid detection.

Trident I will not only double the range of the older

Poseidon missile, but reportedly it will also increase the destructive power carried by each missile from an average of ten

40-kiloton warheads to eight 100-kiloton warheads (see Table 2).

It has also been reported that the Trident II missile, if de26/ Department of Defense Authorization, Fiscal Year 1977,

Hearings before the Senate Armed Services Commi11ee, 94:2

(1976), Part 12, pp. 6548-49.

25

w
.LJIIIIIJUl -1L_

ployed, could carry 14 150-kiloton warheads or seven MK-12A

350-kiloton warheads. 27/

One area of potential submarine vulnerability that does

concern the Navy involves the methods used to receive communications. At the present time, submarines use an antenna close

to or above the surface of the ocean for this purpose. As a

result, a Soviet satellite system that could detect these antennas

might pose a threat to the survivability of all or part of the

submarine force. For this reason, the Navy has proposed construction of an Extremely Low Frequency (ELF) communications

system, called Seafarer, that would allow receipt of messages

without the necessity of bringing either the submarine or its

antenna close to the surface where it is most vulnerable. Therefore, if a threat to submarine concealment should develop, serious

consideration should be given to construction of an ELF-like

communication system.

While submarines at sea are now very survivable and will

likely remain so into the foreseeable future, submarines in

port remain highly vulnerable. The Trident submarine offers

the promise of future improvement in this area as well. About 55

percent of the Polaris and Poseidon submarine force is maintained

at sea during peacetime. 28/ Although Defense Department officials have stated that this percentage can be raised to almost 99

percent of submarines not in overhaul during a crisis, 29/ or

about 80 percent of the total submarine force, this leaves a large

part of the U.S. sea-based deterrent vulnerable to a surprise

attack. With such advances as a longer life reactor core and

improved logistics facilities, however, Trident submarines are

expected to maintain a peacetime at-sea rate of 66 percent. 30/

This represents an increase in potential survivability of 20

percent and is equivalent to the deployment of additional submarines and missiles.

2T/ See "New Propellant Evaluated for Trident Second Stage,"

Aviation Week and Space Technology, October 13, 1975, pp.

16-17.

28/ Senate Armed Services Committee, Department of Defense

Authorization, Fiscal Year 1978, Part 10, p. 6621.

29/ Ibid., p. 6624.

30/ Ibid., p. 6621.

26
In sum/ the U.S. submarine force, which carries approximately

half of all the warheads in the U.S. strategic nuclear arsenal,

appears to be the most survivable part of the TRIAD. Programs now

underway or options available in the future should maintain this

survivability into the foreseeable future.

THE VULNERABILITY OF THE TRIAD

Although it is useful to examine the vulnerability of the

three elements of the strategic TRIAD individually, it is the size

of all surviving U.S. forces that determines whether a dangerous

vulnerability to a Soviet first strike exists. It is likely that

an adversary interested in a counterforce strike against the

United States would attack all three forces together. To do

otherwise would only increase the damage that surviving American

forces could inflict in a nuclear war.

To attack all three elements of the U.S. strategic TRIAD

together, however, would introduce new complications for the

attacker, since each part might contribute to the survivability of

another. For example, simultaneous attacks on bomber bases and

ICBM fields might provide the irrefutable evidence of nuclear war

necessary for a decision to launch ICBMs on warning, a possibility

that would have to give a potential attacker cause for concern.

Furthermore, detection of preparations for an attack, such as the

positioning of a large number of missile-carrying submarines close

to American shores or unusual activity in enemy ICBM fields, might

allow the United States to put a much larger percentage of its own

forces on peak alert, thereby increasing their survivability.

Because of these interactions, certain ambitious enemy attacks,

such as a surprise attack on alert bombers, would probably be

especially risky undertakings.

U.S. Vulnerability in the Mid-1980s

The worst case faced by the United States through the early

1980s would be a comprehensive surprise attack on U.S. nuclear

forces in their day-to-day alert posture. Although it is difficult to find a motive for an unprovoked surprise attack, this

scenario does provide a lower bound for the number of U.S. surviving forces. In such an attack, Soviet submarine-launched

missiles would be targeted against U.S. bomber bases, and 70

percent of the B-52 force would be destroyed. Attacks on U.S.

submarine ports would be expected to destroy the 45 percent of the

Poseidon fleet and the 34 percent of the Trident force not at sea.

The U.S. ICBM force would come under attack by some 260 SS-18

27

I II IB I
LIIIIWI

missiles, each carrying eight 1.5 megaton warheads accurate to

perhaps 1,200 feet. After such a surprise attack, the United

States would probably be left with about 6,400 warheads and 1,800

equivalent megatons. (The Soviets would have a reserve force

consisting of about 6,000 warheads and 6,000 equivalent megatons.)

Since 1,000 Poseidon SLBM warheads could destroy about

75 percent of the Soviet industrial targets (Trident warheads will

be even more destructive), and since the same number of cruise

missiles could destroy over 80 percent of the Soviet industrial

base, the United States would have more than enough weapons in

both the bomber and submarine parts of the TRIAD to destroy the

Soviet Union as a modern industrial society. 31/ Thus, given the

survivability of at-sea submarines and alert bombers, a Soviet

counterforce attack on U.S. ICBM silos, submarine ports, and

bomber bases does not offer the prospect of successful damagelimiting. In addition, since the United States would have more

weapons than those required for attacks on Soviet cities, other

U.S. retaliatory options, such as attacks on Soviet military

targets, would be available after a Soviet first strike. Moreover, the United States could maintain its nuclear force over an

extended period of time;, since most of the surviving U.S. weapons

would be in submarines, which can remain at sea and effective for

weeks or months.

If it is assumed that a nuclear war would not start with a

totally unprovoked surprise attack, but rather after a period

of rising tensions, then U.S. forces would be in a high state of

readiness, often referred to as a generated alert posture, at the

time of the attack. In this case at least 80 percent of the

bomber force 32/ and 75 to 85 percent of the submarine-based

force 33/ would survive; a counterforce attack, leaving the United

States with significantly more warheads and equivalent megatons

than in the surprise attack scenario. An attack on U.S. forces in

a generated alert posture would leave the United States with a

31/ For an examination of the retaliatory damage that U.S. forces

could do, see the forthcoming companion paper on retaliatory

issues.

32/ Military Posture and H.R. 11500, Hearings before the House

Armed Services Committee, 94:2 (1976), Part 5, p. 264.

33/ Senate Armed Services Committee, Department of Defense

Authorization, Fiscal Year 1978, Part 10, p. 6621.

28
substantial force of over 10,000 warheads and 3,000 equivalent

megatons.

U.S. Vulnerability in the Mid-to-Late 1980s

By the mid-to-late 1980s, the vulnerability of U.S. strategic

forces may grow. In particular, if the Soviets develop and deploy

an ICBM accurate to about 600 feet,, the survivability of the

Minuteman force could be seriously threatened. The shrinkage of

the submarine force with the block retirement of the Poseidon

fleet during this same period will also reduce the number of

submarine-based missiles, although the increased payload and

at-sea availability of the Trident force will somewhat offset this

trend. If the Soviets were to attack U.S. forces in their day-today alert posture, and if about 90 percent of the ICBM force were

destroyed, the United States would still have over 4,500 warheads

and 1,400 equivalent megatons.

In the more likely case of a U.S. generated alert posture,

the United States would have over 8,000 warheads and 2,700 equivalent megatons. The expected results of these Soviet counterforce strikes are summarized in Table 3. _34/

All the results presented above are expected value results

based on specific assumptions about £he operational performance of

weapon systems in terms of accuracy, reliability, warhead yield,

silo hardness, and the ability to avoid fratricide. Because

a great deal of uncertainty surrounds estimates of these parameters, the Soviet leadership would have to consider the range

of reasonable attack outcomes as well as point estimates. Given

large variations in the number of U.S. ICBMs that would survive a

Soviet attack against them, a counterforce strike would entail

great risks. 35/

34/ Results for 1990 assume an ICBM force without the addition of

MX or MK-12A warheads on Minuteman III missiles, an SIBM

force based in five Poseidon submarines and 20 Trident boats

(but without Trident II missiles), and a bomber force identical to that of the middle 1980s (see Table 2, second

part).

35/ For details on attack outcome variations, see Appendices B

and C.

29

Illlllil
TABLE 3. U.S. STRATEGIC FORCES SURVIVING A FIRST STRIKE

OJ

o

Day-to-Day Alert

ICBMs a/

SLBMs

Bombers

Total Survivors

(Percent)

Launchers

466

440

120

1,026

(47)

Warheads

968

3,904

1,580

6,452

(46)

(Middle 1980s)

Equivalent

Megatons

479

667

696

1,842

(40)

(1990)

Launchers

466

560

312

1,338

(61)

Day-to-Day Alert

ICBMs a/

SLBMs

Bombers

Total Survivors

(Percent)

Launchers

93

360

120

573

(29)

Warheads

193

2,880

1,580

4,653

(39)

Equivalent

Megatons

96

634

696

1,426

(32)

Launchers

93

472

312

877

(44)

Generated Alert

Warheads

968

4,992

4,152

10,112

(73)

Equivalent

Megatons

479

842

1,824

3,145

(69)

r

B

_

e

*

Generated Alert

Warheads

193

3,776

4,152

8,121

(69)

Equivalent

Megatons

96

831

1,824

2,751

(62)

a/ Number of surviving U.S. ICBMs assumes that Soviets fire two warheads, both programmed for groundburst, at each silo.
CHAPTER IV. U.S. COONTERPORCE CAPABILITY

DETERRENCE AND STRATEGIC STABILITY

It is often suggested that the proper response to the

growing Soviet counterforce threat is the development of a

significant U.S. counterforce capability. The reasoning is

that, even though U.S. forces surviving a Soviet first strike

would probably be large enough to destroy Soviet cities, the

United States would have few credible responses to a counterforce

attack, since retaliation against Soviet cities would surely be

returned in kind. Unless U.S. forces were capable of retaliation

against the Soviet nuclear arsenal, the Soviet Union might be

tempted to attack U.S. strategic forces, and especially the ICBM

part of that force, in order to reduce U.S. options or shift the

balance of strategic power against the United States. Such an

attack might be particularly tempting if the United States

had no way to respond in kind and if the Soviet leadership

could convince themselves that U.S. leeiders would never carry out

the threat to destroy Soviet cities as long as U.S. cities remained intact. On the other hand, if a U.S. counterstrike

against Soviet strategic forces could succeed in drawing down the

Soviet arsenal to a level approximating that of the surviving U.S.

force, then no advantage could be gained from a Soviet first

strike against the United States. Thus, in an era of growing

Soviet counterforce capability, deterrence may depend on U.S.

acquisition of a second-strike counterforce capability. In recent

years official Defense Department statements have hinted at a

growing acceptance of such a second-strike counterforce doctrine.

No opponent should think that he could fire at some of

our Minuteman or SAC bases without being subjected to,

at the very least, a response in kind. No opponent

should believe that he could attack other U.S. targets

of military or economic value without finding similar

or appropriate targets in his own homeland under attack. No opponent should believe that he could blackmail our allies without risking his very capability

for blackmail. I/

I/ James R. Schlesinger, Annual Defense Department Report, FY

1976 and FY 197T, pp. II-4 and II-5.

31

20-694 O - 78 - 4
UJillJUl .11

An even more direct statement of a second-strike counterforce

doctrine was made in 1976 in hearings before the Senate Armed

Services Committee:

In attempting to retaliate for an attempted disarming

first strike/ one possibility, of course, is that of

wiping out the Soviet Union. However, I think that

a better way of responding is to wipe out what forces

he holds back—his remaining blackmail capability—

and, hence leave him in a position where he is worse

off having executed the strike than not having executed

it. If he is worse off doing it, he is not likely to

do it. 2/

Several objections have been raised to the development of

U.S. counterforce capability. Perhaps the most serious problem

with U.S. forces designed for second-strike counterforce stems

from the possibility that they would be seen as first-strike

weapons, and thus be destabilizing. Two types of nuclear stability might be threatened by the development of U.S. counterforce

capability: crisis stability and arms control stability. The

first kind involves the incentives to strike first that each side

would face in an international crisis. There may be an inescapable dilemma involved in the procurement of second-strike counterforce capability: a U.S. arsenal large enough to attack Soviet

ICBMs after having absorbed a Soviet first strike would be large

enough to threaten the Soviet ICBM force in a U.S. first strike.

Moreover, the Soviet Union, looking at capabilities rather than

intentions, might see a U.S. second-strike capability in this

light. Faced with a threat to their ICBM force. Soviet leaders

facing an international crisis might have an incentive to use

their missiles in a preemptive strike before they could be

destroyed by the United States. The Soviets might well be far

more sensitive to a threat to the survivability of their ICBMs

than the United States. The Soviets place far more emphasis on

their ICBM force than does the United States, since the submarine

and bomber segments of their nuclear arsenal are significantly

less capable than those of the United States. Only 11 percent of

2/ Statement of John B. Walsh, Deputy Director, Strategic and

Space Systems, Office of the Director of Defense Research and

Engineering, in Department of Defense Authorization, Fiscal

Year 1977, Hearings before the Senate Armed Services Committee, 94:2 (1976), Part 11, p. 5930.

32
the Soviet submarine force is at sea at any one time, leaving the

rest vulnerable to surprise attack. 3/ Furthermore, in light of

the sophisticated nature of U.S. antisubmarine warfare capabilities and the fact that Soviet submarines are considered to be far

noisier than their U.S. counterparts, even Soviet submarines at

sea may be vulnerable, although longer-range Soviet SLBMs have

reduced this vulnerability. In any event, the destructive power

of at-sea Soviet SIBMs is limited because of the primitive nature

of Soviet sea-based MIRV capability. Soviet bombers are also much

smaller in number and in capability than their American counterparts (see Table 1).

Table 4 presents the expected outcome of three hypothetical

U.S. first strikes against the Soviet ICBM force shown in Table

1. Several important implications can be drawn from these results. First, the counterforce capability of Minuteman III

missiles against Soviet ICBMs seems to be comparable to the threat

posed by the current generation of Soviet missiles to U.S. ICBMs;

both sides would be able to destroy about 40 to 60 percent of the

other's silo-based ICBMs. Specifically, 550 Minuteman III missiles with improved accuracy, each carrying three warheads, would

be expected to destroy about 43 percent of the Soviet ICBM force.

If the more accurate, more powerful MK-12A warhead were deployed

on all 550 Minuteman III missiles, the United States could destroy

about 64 percent of the Soviet land-based missile force in a first

strike.

Second, the U.S. MX missile, with its reported ability to

carry ten MK-12A warheads to within 400 feet of their targets, 4/

potentially could destroy about 92 percent of the Soviet Union's

ICBMs, leaving about 100 missiles, 600 warheads, and 500 equivalent megatons in the Soviet land-based missile force. For comparison, only about 40 percent of Soviet ICBMs could be destroyed

by a force of 550 Minuteman III missiles with improved accuracyThis result, when combined with consideration of the qualitative

inferiority of the Soviet submarine force and the small size of

the bomber force, indicates that deployment of a large number of

MX missiles could pose a significant first-strike threat to the

Soviet Union.

3/ General George S. Brown, United States Military Posture

for FY 1978, p. 14.

4/ See "MX Deployment Urged for Parity," Aviation Week and

Space Technology, December 5, 1977, p. 14.

33

ir in
I

TABLE 4. SOVIET ICBMs SURVIVING A U.S. FIRST STRIKE

U.S. Weapons Used Equivalent

in First Strike Percent Missiles Warheads Megatons

550 Minuteman III 57 791 3,652 2,984

550 Minuteman III

with MK-12A 3$ 508 2,542 2,124

300 MX 8° 108 603 523

NOTE: Assumes U.S. programs two groundbursts per target if

enough warheads are available. See Table 1 for pre-attack

Soviet ICBM force. Soviet modernized silos assumed

to be hardened to 2,000 pounds per square inch; 550 pounds

per square inch for older SS-lls. MX assumed to carry ten

350-kiloton warheads with CEP of 400 feet and reliability

of 0.85. See Table 2 for Minuteman III and MK-12A estimates.

Many opponents of U.S. counterforce capabilities believe

that weapons threatening to the Soviet ICBM force would be extremely dangerous in a crisis. They argue that the Soviets would

then have an incentive to strike first, since allowing the United

States to fire first would result in the loss of a large portion

of the Soviet force. Thus, paradoxically, a U.S. attenpt to match

Soviet counterforce potential might serve to increase, rather than

reduce, the possibility of a Soviet attack. These critics also

maintain that threats to the Soviet strategic deterrent would

compel the Soviet Union to build new weapons to compensate for the

vulnerability of their silo-based ICBMs. This Soviet reaction

might bring with it not only renewed hostility, but also new

weapons threatening to U.S. national security.

Others believe that improved U.S. counterforce capability

is unnecessary. Even without the development of an expensive

capability to destroy Soviet ICBMs, the United States would have

several credible response options short of retaliation against

Soviet cities in the event of a Soviet counterforce attack.

One possibility would be to retaliate against Soviet conventional

military forces. Alternatively, the United States could choose

to attack other Soviet nuclear forces, such as submarine ports,

bomber bases, and command and control facilities.

34
Leaving aside these philosophical issues of deterrence and

stability, several questions about the effectiveness of secondstrike counterforce weapons have been raised. As discussed

above, such a counterforce capability has been justified as a

means of enhancing deterrence of a Soviet nuclear attack by

insuring that the Soviet Union could not gain an advantage by

attacking U.S. strategic forces. Therefore, it is useful to

examine the ability of present and proposed U.S. weapons to

redress an imbalance of nuclear power (measured in terms of

surviving ICBMs) created by a Soviet first strike, and thereby to

deter such an attack. In doing so, U.S. weapons should be separated into those forces that are silo-based and those that are

mobile-based. Silo-based weapons are examined first.

SILO-BASED COUNTERFORCE CAPABILITY

The United States has three possible candidates for silobased counterforce weapons: the present force of 550 accuracyimproved Minuteman III missiles; a Minuteman III force upgraded by

the addition of more accurate,.higher-yield MK-12A warheads; and a

force of more accurate, more powerful MX missiles in Minuteman

silos.

The MX missile, now in the research and development stage

and available for deployment by the middle 1980s, would be an

especially formidable counterforce weapon. As mentioned earlier,

the MX could reportedly carry ten MK-12A warheads to within 400

feet of their targets. Although now planned for deployment in

either hardened underground trenches or above-ground shelters and

justified as necessary for the destruction of a growing number of

industrial and political targets in the Soviet Union, 5/ MX

missiles in silos might be a timely and inexpensive means of

developing a second-strike counterforce capability. The Minuteman

III missile and an upgraded version incorporating the MK-12A

warhead are described in Table 2.

If deployed in silos, all three of these U.S. weapons would

face an increasingly challenging task in their second-strike

counterforce roles as the Soviets continue to deploy their new

generation of more accurate MIRVed ICEMs. This is so because

improved Soviet counterforce capability decreases the number

5/ See Senate Armed Services Committee, Department of Defense

Authorization, Fiscal Year. 1977, Part 11, p. 6520.

35

111
JJM1IL .1.

of U.S. silo-based missiles that can be expected to survive a

first strike, thus reducing the U.S. retaliatory force. Development and deployment of a new generation of Soviet ICBMs accurate

to 600 feet would reduce even further the number of U.S. missiles

expected to survive, making a second-strike attempt to redress the

balance more difficult still. Table 5 shows the results of

U.S.-Soviet counterforce duels both after the Soviet first strike

and after the U.S. second strike.

With respect to the threat posed by full deployment of

current generation Soviet ICBMs, the results in Table 5 indicate

that in order successfully to redress an ICBM imbalance resulting

from a Soviet first strike on silo-based missiles, the United

States would need to deploy more powerful counterforce weapons

than it currently possesses. In fact, even with deployment

of higher-yield MK-12A warheads on all 550 Minuteman III missiles

(not currently planned by the Defense Department), a first-strike

imbalance could not be reversed. Deployment of 300 MX missiles

in Minuteman silos, on the other hand, would enable the United

States to "win" an ICBM exchange with a full force of the current

generation of Soviet missiles. In this case, the United States

would be expected to end up with 329 missiles compared with 211

surviving Soviet ICBMs.

The situation changes dramatically, however, if the Soviets

deploy ICBMs accurate to 600 feet, an option that might be

available to them by the time MX is ready for deployment in the

mid-1980s. In this case the Soviet first strike would destroy

such a large percentage of the U.S. ICBM force that a second

strike by the surviving MX missiles would fall far short of

redressing an imbalance. In fact, after such an exchange the

Soviets would be expected to have 876 ICBMs compared with 79 U.S.

land-based missiles. As a result, it appears that even the most

powerful silo-based weapons might not be able to support a viable

second-strike counterforce posture over the long run, unless the

United States adopts a dangerous launch-on-warning posture.

Most importantly, powerful U.S. counterforce weapons, such

as MX, if deployed in vulnerable missile silos, might be especially tempting targets for a Soviet leadership convinced that war

with the United States was imminent. In this case the Soviets

might strike first against U.S. ICBMs in order to protect their

own nuclear deterrent, since to wait would risk the destruction of

the Soviet land-based missile force. Thus, while it might be

difficult to find rational motives for a Soviet first strike under

present circumstances, the deployment of a weapon as threatening

as the silo-based MX might supply one.

36
TABLE 5. TOTAL SURVIVING SOVIET AND U.S. ICBMs AFTER SOVIET

FIRST STRIKE AND U.S. SECOND STRIKE

U.S. ICBM Forces Involved in

Counterforce Exchange

Force A a/ Force B b/ Force C c/

With 1,200 ft. Soviet CEP

After Soviet First Strike

Soviet 1,135 1,135 1,135

U.S. 466 466 466

After U.S. Second Strike

Soviet

U.S.

800

215

658

215

211

329

With 600 ft. Soviet CEP

After Soviet First Strike

Soviet 1,135 1,135 1,135

U.S. 112 112 112

After U.S. Second Strike

Soviet

U.S.

1,069

52

1,032

52

876

79

NOTE: Results assume that Soviet attack uses 264 SS-18s or SS-18

follow-ons, programming two groundbursts per U.S. silo to

insure against missile and warhead failure. U.S. and

Soviet modernized silos assumed to be 2,000 pounds per

square inch; 550 pounds per square inch for older Titan II

and SS-11 silos.

a/ 550 Minuteman Ills, 450 Minuteman Us, 54 Titan Us. Only

surviving Minuteman Ills used in U.S. second strike.

b/ 550 Minuteman Ills equipped with MK-12A warheads, 450 Minuteman Us, 54 Titan Us. Only surviving Minuteman Ills used in

U.S. second strike.

c/ 300 MXs, 250 Minuteman Ills, 450 Minuteman Us, 54 Titan

Us. Only surviving MXs used in U.S. second strike.

37

Him IT
L

MOBILE-BASED COUNTERFORCE CAPABILITY

The United States has three options for the development

of counterforce weapons in survivable mobile basing systems.

These include: MX missiles in trenches or shelters, 6/ Trident

II missiles in Trident submarines, and bomber-delivered weapons

such as cruise missiles. These weapons have different implications for strategic stability than do silo-based forces.

MX Missiles

Although MX missiles in trenches or shelters would probably

be as threatening to Soviet ICBMs as those in Minuteman silos,

mobile-based missiles would be much less vulnerable to a Soviet

attempt to destroy them. Current plans call for the deployment of

each MX missile in concrete-encased trenches 10 to 12 miles long,

buried beneath five feet of dirt. Since 300 missiles could move

at random in over 3,600 miles of trench, an attacker would have to

launch about 6,000 perfectly placed one-megaton warheads in an

attempt to destroy all 300 mobile-based MXs. 7/ An attack of this

magnitude would approach a self-disarming strike, and thus MX

missiles in trenches would probably not be attacked. Moreover,

improvements in Soviet missile accuracy would not threaten this

survivability, since mobile U.S. missiles, unlike silo-based

missiles, would be impossible to target. Two implications follow

from this invulnerability. First, as second-strike weapons,

6/ Basing in covered trenches is currently the preferred plan for

MX deployment. If this concept proves to be impractical or

too costly, shelter-basing would be used. In the latter

system each MX missile would be moved at random from one

protective above-ground shelter to another. Since the Soviet

Union would not know which shelter the missile was in at any

given time, all the shelters would have to be attacked to

insure that the missile was destroyed.

7/ If trenches are hardened to 600 pounds per square inch (see

"Strategic Force 'Options Related to SALT II," Congressional

Research Service, Issue Brief IB77046, May 19, 1977, p. 7),

each one megaton warhead could destroy slightly less than

two-thirds of a nautical mile of trench. It should be noted,

however, that trench h,ardness has yet to be determined. Lower

hardness would require more miles of trench to guarantee the

same survivability, thus increasing program cost.

38
trench- or shelter-based MX missiles would not be sensitive to

improvements in accuracy or to changes in the number and size of

warheads carried on Soviet ICBMs. As a result, unlike the case

for silo-based weapons, a second-strike counterforce doctrine

might be viable over the long run.

Second, crisis incentives would be different for mobile-based

MXs. In this case, the Soviets would not be able to knock out the

weapons that threaten their own ICBMs, and, therefore, little

incentive to attack these weapons would exist. On the other hand,

many argue that the Soviets would still have an incentive to

use their weapons for something, such as attacks on vulnerable

U.S. forces (for example, silo-based U.S. ICBMs, in-port submarines, or non-alert bombers) or even on U.S. cities, since to

wait would risk their loss. Others argue that MX deployment would

enhance, rather than undermine, crisis stability. Because MX

missiles in trenches or shelters would be invulnerable, the

Soviets would have few effective ways to use their weapons. If

the Soviets used part of their ICBMs for attacks on other U.S.

military targets, MX missiles could be used to destroy the rest of

the Soviet ICBM force. Such an exchange would leave the Soviets

worse off than before their attack. Attacks on U.S. cities would

serve little purpose, since they would bring about U.S. retaliation against Soviet cities.

The implications of survivable counterforce weapons for arms

control are also disputed. Many observers contend that mobile

missiles such as the MX would mean the end of arms control agreements, since concealed weapons would be impossible to count.

Others counter that mobile missiles might be counted at "chokepoints" through which all missiles would have to pass, such as the

entrances to underground tunnels or to the missile fields themselves. In any case, it seems clear that the threat to the

survivability of Soviet ICBMs posed by the MX would cause some

Soviet reaction. Some analysts believe that a threat to Soviet

ICBMs is an effective way to force the Soviet Union into mobile

basing systems of their own, and that such a mobile ICBM program

might divert Soviet resources away from weapon programs threatening to the United States. Mobile ICBM systems on both sides might

also serve to reestablish a stable situation similar to the

era of single-warhead missiles when an attacker could never

destroy more of the enemy's missiles than he used in a first

strike. The Department of Defense apparently sees the counterforce potential of the MX in this light.

If the life of the fixed, hard ICBMs cannot be extended,

then stability requires both sides to improve their

land-based forces enough so that they are more diffi39
il

cult to target by the other side. The United States

should not accept a strategic relationship in which we

must bear the heavier costs of alternative basing while

the Soviets are allowed the luxury of retaining their

fixed ICBMs. Since high accuracies can be built into

mobile as well as fixed systems, the Soviet leadership

should be aware that if the United States moves toward

mobility, the Soviets will have strong incentives to go

mobile as well. 8/

Other analysts believe that the Soviet reaction to improved

U.S. counterforce capability might not be so stabilizing. For

example, the Soviet Union might adopt a dangerous launch-onwarning posture, or they might move to a system of mobile ICBMs

that would be more difficult to count than the U.S. MX system.

Some analysts speculate that the Soviets might develop new weapons

capable of posing offsetting threats to the U.S. deterrent. They

believe that U.S. national security interests would be better

served by an arms control agreement that reduced the threat to

silo-based ICBMs and eliminated the need for a mobile missile

system as expensive as the MX. For example, improvements in Soviet

missile accuracy and counterforce capability might be restricted

by placing limits on the missile flight tests needed to develop

new guidance systems. 9/ If verification of measures designed to

restrict guidance improvements proved to be impractical, severe

restrictions on large MIRVed Soviet ICBMs would be the only way to

limit the threat to U.S. silo-based ICBMs. The Soviet Union has

consistently resisted these sorts of restrictions, however.

For this reason, proponents of U.S. counterforce weapons argue

that the only way to force the Soviet Union into an agreement that

limits the threat to U.S. ICBMs is to present that country with a

threat to its own ICBM force, thereby supplying a powerful source

of U.S. bargaining leverage. Because the Soviet Union is so

dependent on its ICBM force, they might be especially interested

in preventing U.S. deployment of a weapon as threatening as MX.

If the counterforce capability of the MX missile is judged to

be on balance destabilizing, but a response to the growing vulner8/ Donald A. Rumsfeld, Annual Defense Department Report, FY

1978, p. 72.

9/ Flight test restrictions would, of course, restrict the

development of new U.S. missiles, such as the MX ICBM and the

Trident II SLBM.

40
ability of silo-based ICBMs is desired, then a less threatening

mobile ICBM might be developed to reestablish the survivability of

the U.S. land-based missile force. Although the trench- or

shelter-basing would constitute most of the cost of a mobile ICBM

system, some money might be saved by reducing the capability of

the missiles. Such a course would reflect a belief that the

United States would not need a counterforce capability for retaliation against Soviet ICBMs remaining after an attack on vulnerable

U.S. forces, such as older silo-based missiles and in-port submarines and non-alert bombers. U.S. restraint in the development

of counterforce capability would also imply a judgment that it

would be better to allow the Soviet Union to remain dependent on

silo-based ICBMs rather than to threaten them and face the uncertainties surrounding predictions about the likely Soviet reaction

to a threat to their land-based missile force.

Trident II Missiles

The Trident II missile, a larger arid more accurate submarinelaunched missile currently in the research and development stage,

will provide an additional option to develop a U.S. counterforce

capability in the mid-to-late 1980s. Because at-sea Trident

submarines will probably be undetectable and thus invulnerable

into the foreseeable future, a submarine-based counterforce

capability would, like mobile MX missiles, be highly survivable

and thus able to support a second-strike counterforce policy over

the long run. Developing SLBMs capable of effective counterforce

attacks may, however, be a challenging task, since it is very

difficult to maintain extreme accuracy in a missile system based

in submarines that do not have precise information on their

position and velocity. External aids, such as Global Positioning

System satellites that will be able to give precise information on

position and velocity by the early 1980s, might be used to supplement Trident II's own inertial guidance. Dependence on external

aids may, however, create new system vulnerabilities—in this case

the possible vulnerability of the Global Positioning System

satellites.

A sea-based counterforce capability would also require the

procurement of additional Trident submarines beyond the twentysome needed for attacks on cities, as well as the development and

procurement of more sophisticated Trident II missiles to replace

the smaller, less accurate first-generation Trident I missiles.

With a force of 32 Trident submarines, armed with 768 more powerful Trident II missiles, the warheads carried by 12 submarines

would provide enough weapons for the destruction of about 80

percent of Soviet industrial capacity and for a survivable

strategic reserve. The remaining twenty submarines would provide

41
liliil

enough warheads for a two-on-one counterattack against the Soviet

reserve ICBM force. Thus, the construction of about twelve extra

Trident submarines and the development and procurement of the

Trident II missile would be: required for a U.S. sea-based counterforce capability.

Cruise Missiles

One way to get around some of the dilemmas involved in the

deployment of second-strike counterforce weapons would be to use

bombers in this role. Because bombers take several hours to reach

their targets and can deliver nuclear weapons with great accuracy,

they might provide a means to strike back against Soviet nuclear

forces remaining after a first strike against the United States

without posing a first-strike threat to the Soviet Union. In this

role, the extreme accuracy promised by the terrain-matching

guidance system of the cruise missile might be particularly

useful. In fact, a two-on-one counterattack against reserve

Soviet ICBMs by 2,800 cruise missiles accurate to 300 feet (see

Table 2), would leave less than 150 surviving Soviet ICBMs,

assuming cruise missile reliability and penetration probability of

85 percent each.

Some observers argue that, despite their accuracy, cruise

missiles would be poor counterforce weapons. For one thing,

these missiles are said to be vulnerable to low-altitude surfaceto-air missiles that might be used to defend ICBM fields from

counterattacks by cruise missiles, although Department of Defense

officials have stated that U.S. cruise missile technology is

expected to remain ahead of Soviet surface-to-air missile technology. lO/ Aircraft carrying cruise missiles might also be

vulnerable to long-range, advanced Soviet interceptors—especially

if SALT II restrictions on the range of cruise missiles force

missile carriers to fly close to Soviet borders before launching

their weapons.

In addition, many analysts argue that the long flight time of

cruise missiles would allow the preemptive launch of Soviet ICBMs

under attack. There are, however, reasons to question the utility

of such a Soviet response. Since the Soviets would have already

attacked the U.S. ICBM force, the number of targets available for

a second-round Soviet strike would be limited. Attacks on U.S.

See "Pentagon Aides Call Cruise Missile Able to Penetrate

Soviet," New York Times, November 2, 1977, p. 6.

42
cities would serve little purpose, since the United States would

then have little incentive to continue to refrain from retaliation

against Soviet cities. Moreover, a Soviet leadership faced with

the prospect that an attack on U.S. strategic forces would put

their own ICBM force in jeopardy might be more reluctant to launch

the initial attack. Thus, deterrence might be enhanced by the

possibility that U.S. cruise missiles could carry out a secondstrike counterforce attack.

Still others believe that there may be no way to circumvent

the dilemmas posed by the acquisition of counterforce capability.

They argue that the few extra hours needed by cruise missiles

to reach their targets would make little difference to a Soviet

leadership faced with the imminent destruction of their ICBM force

and that the cruise missile might also look like a threatening

first-strike weapon to the Soviet Union. In this view, it is the

combination of the existence of stationary targets such as silobased ICBMs and the development of extremely accurate new nuclear

weapons that threatens to destabilize the nuclear balance.

Because no stationary target can withstand the effects of a direct

hit by a nuclear weapon, long-term nuclear stability may require

that all strategic forces be based in mobile systems such as

submarines, bombers, and mobile ICBMs.

43

nn mi in

CHAPTER V. U.S. OPTIONS

Possible U.S. responses to growing Soviet counterforce

capability will depend upon judgments about the significance of

this vulnerability, the amount and kind of hedging against Soviet

threats desired, and the desirability of developing a U.S. counter force capability. I/

Three possible responses to the growing vulnerability of

silo-based missiles are presented here: finite deterrence, slow

counterforce, and prompt counterforce.

FINITE DETERRENCE

A policy of finite deterrence would be based on the belief

that the Soviet Union would have little to gain from a counterforce attack against U.S. ICBMs and that the U.S. threat to

destroy Soviet cities, even if the actual execution of the threat

were uncertain, should be sufficient to deter any Soviet attack,

including an attack confined to isolated military targets such as

ICBM silos. In practice, even a finite deterrence force of about

20 Trident submarines, 300 B-52s armed with long-range cruise

missiles, bombs, and short-range attack missiles, and the present

force of 1,054 ICBMs would provide enough weapons for large-scale

second-strike attacks on Soviet military targets, in addition to

an ability to destroy the Soviet Union as a modern industrial

society. Such a U.S. force would not, however, provide an effective capability to retaliate against Soviet ICBMs.

A policy of finite deterrence would reflect a judgment that

U.S. counterforce weapons would undermine, rather than enhance,

strategic stability. Critics of U.S. counterforce capability

I/ Strategic force requirements also depend upon judgments about

the desired level and kind of retaliatory capability. For a

discussion of these issues, see the forthcoming companion

paper on retaliatory issues. For a more complete discussion

of U.S. options and estimates of their cost, see the forthcoming CBO Budget Issue Paper for fiscal year 1979 on options

for the 1980s.

45
argue that a threat to the survivability of the Soviet ICBM force,

the most important part of the Soviet nuclear arsenal, would

undermine crisis stability by providing an incentive for the

Soviets to use their weapons before they could be destroyed. The

development of U.S. counterforce capability might also complicate

arms control efforts, since the Soviets would feel compelled to

build additional, and possibly more dangerous, weapons to compensate for the vulnerability of their silo-based missiles.

The total number of ICBMs, submarine missiles, and bombers

required for a policy of finite deterrence would be well under a

SALT II limit of 2,200-2,400 delivery vehicles. On the other

hand, a ceiling of 1,200 ballistic missiles that can be equipped

with multiple warheads would require the retirement of about 80

Minuteman III ICBMs or Poseidon submarine missiles as MIRVed

Trident I missiles are deployed with new Trident submarines. If

B-52s or other aircraft armed with cruise missiles are counted

under SALT II as MIRVed delivery vehicles, then the deployment of

more than 120 cruise missile carriers will require further

retirements.

A decision not to procure weapons capable of destroying

Soviet silo-based ICBMs, such as MX ICBMs, Trident II SLBMs, and

large numbers of bomber-launched cruise missiles, would also

reflect a judgment that the additional capabilities provided by

these sophisticated weapon systems would not be worth their cost.

The forces appropriate for a policy of finite deterrence would

cost about $111 billion (in fiscal year 1978 dollars) from fiscal

year 1979 to fiscal year 2000, $91 billion for operating and $20

billion for investment. Operating the bomber force, at a cost

of over $50 billion, is by far the largest part of total operating

costs, while the completion of the Trident submarine program, at a

cost of over $16 billion, accounts for most of the investment

costs. The forces and cost for a policy of finite deterrence are

presented in Table 6.

SLOW COUNTERFORCE

Cruise missiles could provide the United States with a "slow"

counterforce capability, one that could be used in a second-strike

attack against Soviet ICBMs without posing a first-strike threat

to the Soviet Union's land-based missile force. Many analysts

believe that a U.S. ability to carry out a second-strike counterforce attack would enhance deterrence of a Soviet first strike

against vulnerable U.S. strategic forces such as silo-based

missiles. They believe that without such a capability the United

States would have few attractive ways to retaliate for a Soviet

46
TABLE 6. COSTS OF FORCES FOR FINITE DETERRENCE: BY FISCAL YEARS

(In Millions of Current Dollars)

1979 1980 1981 1982 1983

(In Millions of

FY 1978 Dollars)

1979 through 2000

Present Force of

450 Minuteman II,

550 Minuteman III,

54 Titan II

Operating 850 910 960 1,020 1,080 17,600

20 Trident Submarines

with 640 Trident I

Missiles

Investment a/

Operating b/

2,520

1,170

3,550

1,300

3,050

1,370

3,010

1,410

3,240

1,450

16,400

20,200

165 B-52s with 3,300

Cruise Missiles, c/

and 165 B-52s and 60

FB-llls with SRAM and

Bombs

Investment

Operating e/

0

2,580

0

2,770

760

2,970

1,000

3,160

1,060

3,380

4,100 d/

52,900

Total

(Investment)

(Operating)

7,120 8,530 9,110

(2,520) (3,550) (3,810)

(4,600) (4,980) (5,300)

9,600 10,210

(4,010) (4,300)

(5,590) (5,910)

111,200

(20,500)

(90,700)

NOTES: Costs shown do not include all the costs of maintaining the strategic forces.

Not included are the costs of such functions as command, control, and communications; surveillance; and strategic defense; and the costs of nuclear warheads.

Numbers of missiles and aircraft refer to equipment in operating units. Additional procurement is included in the costs to account for spares, training,

and maintenance.

a/ Trident submarine costs are uncertain and could be higher than indicated. Seven

Trident submarines have been authorized through fiscal year 1978. Twenty-boat

Trident force costs assume a building rate of three submarines every two years

through fiscal year 1980, accelerated to two submarines per year in fiscal year

1981. Number of Trident I missiles includes 160 for deployment in ten Poseidon

submarines.

b/ Submarine operating costs include the Polaris/Poseidon fleet,

c/ B-52s armed with cruise missiles include 75 B-52Ds and 90 B-52Gs.

d/ The B-52 and KC-135 tanker forces will probably have to be replaced in the early

1990s. if the B-52 force is replaced with a comparable mix of advanced penetrating bombers and wide-bodied cruise missile carriers and wide-bodied aircraft

replace the present tanker force, then an additional $30-40 billion (in fiscal

year 1978 dollars) would have to be spent in the 1990s to maintain a strategic

bomber force.

e/ Bomber operating costs include tanker support aircraft.

'¥ III
strike that avoided direct attacks on U.S. cities, since U.S.

retaliation against Soviet cities would only guarantee Soviet

attacks on U.S. cities. On the other hand, if U.S. forces that

survived a Soviet first strike were capable of destroying most of

the Soviet ICBMs held in reserve, then no possible gain would

result from a Soviet attack, and deterrence would be enhanced.

The extreme accuracy promised by the cruise missile's

terrain-matching guidance system would make these weapons very

effective against hardened missile silos, while the cruise missile's low-level flight and small size would provide the Soviet

Union with a difficult air defense task. At the same time,

because bomber-launched cruise missiles would take several hours

to reach their targets, thus providing a "slow" counter force

capability, they would probably not pose a first-strike threat to

the Soviet Union's silo-based ICBM force. As a result, the

Soviets would feel little pressure to launch a preemptive strike

if war were believed to be imminent. Similarly, a large U.S.

cruise missile force might not threaten arms control stability,

since steps to compensate for the vulnerability of Soviet silobased ICBMs would not be necessary. Reliance on cruise missiles

for a retaliatory counterforce strike, however, would make permanent SALT restrictions on cruise missile range unacceptable to

the United States. The counting of bombers carrying cruise

missiles as MIRVed delivery vehicles would require that older

MIRVed Minuteman III or Poseidon missiles be retired as new cruise

missile carriers are added to the U.S. force.

The long flight time of a slow counterforce weapon such as

the cruise missile might increase the risk that the Soviets would

launch some or all of their reserve ICBMs in a second-round

attack before they could be destroyed by counterattacking U.S.

cruise missiles. The utility of such a response is, however,

debatable. Since the Soviets would have already attacked the

U.S. ICBM force, the number of appropriate targets for a secondround Soviet attack would be limited. Attacks on U.S. cities

would serve little purpose, since the United States would then

have little incentive to continue to refrain from retaliation

against Soviet cities.

A slow counterforce policy would, during the period from

fiscal year 1979 through fiscal year 2000, add about $14 billion

(in fiscal year 1978 dollars) to the $111 billion costs for a

policy of finite deterrence. Procurement of 4,800 extra cruise

missiles and 75 cruise missile carriers for the second-strike

counterforce role would cost about $10 billion, while $4 billion

would be required to operate this force. The forces appropriate

for a slow counterforce policy and their costs are presented in

Table 7.

48
TABLE 7. COSTS OF FORCES FOR SLOW COUNTERFORCE: BY FISCAL YEARS

(In Millions of Current Dollars)

1979 1980 1981 1982 1983

(In Millions of

FY 1978 Dollars)

1979 through 2000

75 Wide-Bodied Cruise

Missile Carriers and

4,800 Cruise Missiles

Investment

Operating

10,400

3,900

Present Force of

450 Minuteman II,

550 Minuteman III,

and 54 Titan II

Operating 850 910 960 1,020 1,080 17,600

20 Trident Submarines

with 640 Trident I

Missiles

Investment a/

Operating b/

2,520

1,170

3,550

1,300

3,050

1,370

3,010

1,410

3,240

1,450

16,400

20,200

165 B-52s with 3,300

Cruise Missiles, c/

and 165 B-52s and 60

FB-llls with SRAM and

Bombs

Investment

Operating e/

0

2,580

0

2,770

760

2,970

1,000

3,160

1,060

3,380

4,100 d/

52,900

Total 7,120 8,530 9,110 9,600 10,210 125,500

(Investment) (2,520) (3,550) (3,810) (4,010) (4,300) (30,900)

(Operating) (4,600) (4,980) (5,300) (5,590) (5,910) (94,600)

NOTES: Costs shown do not include all the costs of maintaining the strategic forces.

Not included are the costs of such functions as command, control, and communications; surveillance; and strategic defense; and the costs of nuclear warheads.

Numbers of missiles and aircraft refer to equipment in operating units. Additional procurement is included in the costs to account for spares, training,

and maintenance.

a/ Trident submarine costs are uncertain arj could be higher than indicated. Seven

Trident submarines have been authorized through fiscal year 1978. Twenty-boat

Trident force costs assume a building rate of three submarines every two years

through fiscal year 1980, accelerated to two submarines per year in fiscal year

1981. Number of Trident I missiles includes 160 for deployment in ten Poseidon

submarines.

b/ Submarine operating costs include the Polaris/Poseidon fleet,

c/ B-52s armed with cruise missiles include 75 B-52Ds and 90 B-52Gs.

d/ The B-52 and KC-135 tanker forces will probably have to be replaced in the early

1990s. If the B-52 force is replaced with a comparable mix of advanced penetrating bombers and wide-bodied cruise missile carriers and wide-bodied aircraft

replace the present tanker force, then an additional $30-40 billion (in fiscal

year 1978 dollars) would have to be spent in the 1990s to maintain a strategic

bomber force.

e/ Bomber operating costs include tanker support aircraft.
UMIIIUL .Jf

PROMPT COUNTERFORCE

The MX ICBM and the Trident II submarine-launched missile,

both highly accurate ballistic missiles planned for future deployment in survivable basing systems, would provide a "prompt"

counterforce capability, one that would provide the means to

retaliate against reserve Soviet ICBMs within minutes of a Soviet

first strike. Such a prompt counterforce capability would give

the Soviets little time to launch a second-round attack before the

arrival of counterattacking U.S. missiles. In addition, because

of both physical difficulties and treaty restrictions, it is

unlikely that defenses against ballistic missiles could be developed.

A prompt counterforce policy would be based on the belief

that such a capability, if deployed in survivable basing systems

such as underground tunnels or Trident submarines, would enhance,

rather than undermine, strategic stability. Because survivable

U.S. counterforce weapons would not be vulnerable to a Soviet

preemptive strike designed to knock out U.S. missiles threatening

to their own silo-based ICBMs, the Soviets would have little to

gain from a first strike. In fact, since U.S. counterforce

weapons would be capable of destroying the Soviet ICBMs remaining

after an attack on the United States, and since other U.S. weapons

would be able to retaliate against Soviet cities, the Soviet Union

would have much to lose from an attack on the United States.

U.S. counterforce weapons threatening to Soviet silo-based

ICBMs might also contribute to arms control efforts for two

reasons. First, the prospect of such a threat might force the

Soviet Union into an agreement that limited the counterforce

threat. Second, if an agreement could not be reached, such a

threat might encourage the: Soviets to abandon their large silobased ICBMs for systems that would be more survivable and less

threatening to the United States. In either of these cases,

both sides would be prevented from gaining an ability to attack

the other's land-based missiles, and stability would be enhanced.

Permanent SALT limitations on missile flight tests designed

to prevent improvements in Soviet counterforce capability would

also restrict U.S. development of MX and Trident II missiles, and

a ban on mobile missiles would eliminate a trench- or shelterbased MX option. Limitations on the number of launchers that can

be equipped with multiple warheads would not significantly affect

either the MX or the Trident II option, since older MIRVed weapons, such as Minuteman III ICBMs or Poseidon SLBMs, could be

retired as new systems are deployed.

50
During the period from fiscal year 1979 through fiscal year

2000, a policy of prompt counterforce would add almost $30 billion

(in fiscal year 1978 dollars) to the $111 billion costs for a

policy of finite deterrence. Procurement of 300 MX mobile missiles would cost about $23 billion for investment and $5.5 billion

for operating during this period. Twelve extra Trident submarines

and 768 Trident II missiles would cost about $25 billion for

investment and $3.5 billion for operating. The forces and costs

for a policy of prompt counterforce are presented in Table 8.

51

20-694 O - 78 - 6

Tl M
TABLE 8. COSTS OF FORCES FOR PROMPT COUNTERFORCE: BY FISCAL YEARS

(In Millions of Current Dollars)

1979 1980 1981 1982 1983

(In Millions of

FY 1978 Dollars)

1979 through 2000

300 MX Missiles

in 3,600 Miles

of Trench

Investment a/

Operating

210

0

600

0

(MX Option)

1,230

0

1,830

0

1,700

0

22,900

5,400

Force of

450 Minuteman II,

250 Minuteman III,

and 54 Titan II

Operating b/ 850 910 960 l,Q.20 1,080 14,500

20 Trident Submarines

with 640 Trident I

Missiles

Investment c/

Operating d/

2,520

1,170

3,550

1,300

3,050

1,370

3,010

1,410

3,240

1,450

16,400

20,200

165 B-52s with 3,300

Cruise Missiles, e/

and 165 B-52s and 60

FB-llls with SRAM and

Bombs

Investment

Operating gy

0

2,580

0

2,770

760

2,970

1,000

3,160

1,060

3,380

4,100 £/

52,900

Total 7,330 9,130 10,340 11,430 11,910 136,400

(Investment) (2,730) (4,150) (5,040) (5,840) (6,000) (43,400)

(Operating) (4,600) (4,980) (5,300) (5,590) (5,910) (93,000)

(continued)

NOTES: Costs shown do not include all the costs of maintaining the strategic forces.

Not included are the costs of such functions as command, control, and communications; surveillance; and strategic defense; and the costs of nuclear warheads.

Numbers of missiles and aircraft refer to equipment in operating units. Additional procurement is included in the costs to account for spares, training,

and maintenance.

a/ MX cost, especially the cost to construct underground trenches, is uncertain at

the present time. Costs shown assume trench cost of $2 million per mile.

b/ Three hundred Minuteman III missiles are assumed to be retired as MX missiles are

deployed.

c/ Trident submarine costs are uncertain and could be higher than indicated. Seven

Trident submarines have teen authorized through fiscal year 1978. Twenty-boat

Trident force costs assume a building rate of three submarines every two years

through fiscal year 1980, accelerated to two submarines per year in fiscal year

1981. Number of Trident I missiles includes 160 for deployment in ten Poseidon

submarines.
TABLE 8. (CONTINUED)

(In Millions of Current Dollars)

1979 1980 1981 1982 1983

(In Millions of

FY 1978 Dollars)

1979 through 2000

32 Trident Submarines

and 768 Trident II

Missiles

Investment h/

Operating d/

2,630

1,170

(Trident II Option)

3,430

1,300

3,690

1,370

5,200

1,410

6,050

1,450

41,500

23,800

Present Force of

450 Minuteman II,

550 Minuteman III,

and 54 Titan II

Operating 850 910 960 1,020 1,080 17,600

165 B-52s with 3,300

Cruise Missiles, e/

and 165 B-52s and 60

FB-llls with SRAM and

Bombs

Investment

Operating g_/

0

2,580

0

2,770

760

2,970

1,000

3,160

1,060

3,380

4,100 f/

52,900

Total 7,230 8,410 9,750 11,790 13,020 139,900

(Investment) (2,630) (3,430) (4,450) (6,200) (7,110) (45,600)

(Operating) (4,600) (4,980) (5,300) (5,590) (5,910) (94,300)

d/ Submarine operating costs include the Polaris/Poseidon fleet.

e/ B-52s armed with cruise missiles include 75 B-52Ds and 90 B-52Gs.

I/ The B-52 and KC-135 tanker forces will probably have to be replaced in the early

1990s. If the B-52 force is replaced with a comparable mix of advanced penetrating

bombers and wide-bodied cruise missile carriers and wide-bodied aircraft replace

the present tanker force, then an additional $30-40 billion (in fiscal year 1978

dollars) would have to be spent in the 1990s to maintain a strategic bomber force.

<j/ Bomber operating costs include tanker support aircraft.

h/ Trident submarine costs are uncertain and could be higher than indicated. Seven

Trident submarines have been authorized through fiscal year 1978. Thirty-two

boat Trident force costs assume a building rate of three submarines every two years

through fiscal year 1980, accelerated to three submarines per year in fiscal year

1982. Costs include the procurement of 500 Trident I missiles during the early

1980s, including 160 for deployment in ten Poseidon submarines.

in i ii
TABLE 9. SUMMARY OF COSTS OF THREE OPTIONS: BY FISCAL YEARS

(In Millions of

(In Millions of Current Dollars) FY 1978 Dollars)

1979 1980 1981 1982 1983 1979 through 2000

Finite

Deterrence 7,120 8,530 9,110 9,600 10,210 111,200

Slow

Counterforce

Prompt

Counterforce

Trident II

Option

7,120 8,530 9,110 9,600 10,210

MX Option 7,330 9,130 10,340 11,430 11,910

7,230 8,410 9,750 11,790 13,020

125,500

136,400

139,900

NOTE: Costs shown do not include all the costs of maintaining the strategic

forces. Not included are the costs of such functions as command,

control, and communications; surveillance; and strategic defense; and

the costs of nuclear warheads.

54
APPENDIXES

Iff

APPENDIX A. THE SNAPPER FORCE EXCHANGE! MODEL

The Strategic Nuclear Attack Program for Planning and Evaluation of Results (SNAPPER), developed for the Air Force by the

Rand Corporation, has been used to calculate the missile exchange

results reported in this study. Using damage effects calculations

derived by the Defense Intelligence Agency, the model does Monte

Carlo analyses, varying both weapons performance and weapons

characteristics.

Model inputs include the number of warheads per target, the

number of launchers and the number of warheads per launcher,

missile reliability and accuracy, warhead yield, height of burst,

and target hardness. The values for missile reliability and

accuracy, warhead yield, and target hardness are all allowed to

vary, and the model gives as output both expected value and Monte

Carlo results. Variations in yield are normally distributed.

Variations in missile reliability and target hardness are both

lognormally distributed and skewed to the left, while variations

in missile accuracy are lognormally distributed and skewed to the

right. All results presented are based on. 25 model simulations.

57

¥"

APPENDIX B. U.S. ICBM VULNERABILITY IN THE MID-1980S

The following tables present the detailed expected results

of hypothetical Soviet attacks on the U.S. ICBM force and the

possible variations in these results for the mid-1980s. Only

SS-18 missiles are used in the attacks. All results were derived

with the use of the SNAPPER Force Exchange Model. All 90 Percent

Confidence Intervals are based on 25 simulations.

59

IT" in mum
1LJIJ [JLIL .111

TABLE B-l. ATTACK 1: ONE GROUNDBURST

Percent

Surviving U.S. ICBMs

Missiles Warheads EMT b/

With 1,500 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

59

59

31

267

326

17

610

267

978

17

1,262

267

300

74

641

With 1,200 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

46

46

19

205

251

10

466

205

753

10

968

205

231

43

479

ASSUMPTIONS:

1. 264 SS-18s with eight 1.5 megaton warheads used in attack.

Two warheads, both programmed to groundburst, fired at each

U.S. silo. At most, one detonation per silo.

2. SS-18 reliability = 0.75; compounded reliability = 0.94.

3. Minuteman silo hardness of 2,000 pounds per square inch; 550

pounds per square inch for Titan.

a/ Circular Error Probable,

b/ Equivalent megatons.

60
Figure B-1.

Surviving U.S. Minuteman Force:

90 Percent Confidence Intervals for Attack 1

Percent

100

90

80

70

60

50

40

30

20

10

Upper 90% Confidence Limit

Expected Value Result (from Table B-1)

Lower 90% Confidence Limit

1,500 feet 1,200 feet

Circular Error Probable of Soviet ICBMs

ASSUMPTIONS:

1. SS-18 Circular Error Probable (CEP) varies from a lower limit of 1,300 ft. to an upper 90

percent confidence level of 1,800 ft. for 1,500 ft. CEP, and from a lower limit of 1,000 ft.

to an upper 90 percent confidence level of 1,500 ft. for 1,200 ft. CEP.

2. For SS-18 yield, one standard deviation equals 300 kilotons.

3. SS-18 compounded reliability varies from an upper limit of 98 percent to a lower 90 percent

confidence level of 85 percent.

4. Minuteman silo hardness varies from an upper limit of 2,500 pounds per square inch to a lower

90 percent confidence level of 1,000 pounds per square inch.

61

fir ir
JUL .Jl

TABLE B-2. ATTACK 2: ONE AIRBURST, ORE GROUNDBURST

Percent

Surviving U.S. ICBMs

Missiles Warheads EMT b/

With 1,500 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

50

50

21

224

274

11

509

224

822

11

1,057 524

With 1,200 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

38

38

14

170

207

7

384

170

621

7

798

170

190.6

30.3

391

ASSUMPTIONS:

1. 264 SS-18s with eight 1.5 megaton warheads used in attack;

cross-targeting of two warheads per silo.

2. SS-18 reliability = 0.75.

3. Height of burst for first-round airbursts is 1,600 ft. (140

scaled ft.).

4. Height of burst error of 20 percent, resulting in overall CEPs

for airburst weapons of 1,650 ft. (for 1,500 ft. missile CEP)

and 1,400 ft. (for 1,200 ft. missile CEP). Note: height

of burst error of zero would result in Minuteman survivability

of 47 percent for 1,500 ft. CEP and 33 percent for 1,200 ft.

CEP.

5. Minuteman silo hardness of 2,000 pounds per square inch; 550

pounds per square inch for Titan.

6. 100 percent fratricide avoidance,

a/ Circular Error Probable.

b/ Equivalent megatons.

62
Figure B-2.

Surviving U.S. Minuteman Force:

90 Percent Confidence Intervals for Attack 2

Percent

100

90

80

70

60

50

40

30

20

10

0

Upper 90% Confidence Limit

Expected Value Flesult (from Table B-2)

Lower 90% Confidence Limit

1,500 feet 1,200 feet

Circular Error Probable of Eioviet ICBMs

ASSUMPTIONS:

1. For groundburst weapons, SS-18 Circular Error Probable (CEP) varies from a lower limit of

1,300 ft. to an upper 90 percent confidence level of 1,800 ft. for 1,500 ft. CEP, and from

a lower limit of 1,000 ft. to an upper 90 percent confidence level of 1,500 ft. for 1,200 ft.

CEP. For airburst weapons, CEP varies from a lower limit of 1,450 ft. to an upper 90 percent confidence level of 1,950 ft. for 1,650 ft. airburst CEP, and from a lower limit of 1,200

ft. to an upper 90 percent confidence level of 1,700 ft. for 1,400 ft. air burst CEP.

2. For SS-18 yield, one standard deviation equals 300 kilotons.

3. SS-18 reliability varies from an upper limit of 85 percent to a lower 90 percent confidence

level of 60 percent.

4. Minuteman silo hardness varies from an upper limit of 2,500 pounds per square inch to a lower

90 percent confidence level of 1,000 pounds per square inch.

63
TABLE B-3. ATTACK 3: ONE AIRBURST, ONE GROUNDBURST, AND REPROGRAMMING FOR RELIABILITY

Surviving U.S. ICBMs

Percent Missiles Warheads EMT b/

With 1,500 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

44

44

14

200

244

452

200

732

8

940

200

225

35

460

With 1,200 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

32

32

8

142

174

4

320

142

522

4

668

142

160

17

319

ASSUMPTIONS:

1. 264 SS-18s with eight: 1.5 megaton warheads used in first wave;

cross-targeting of two warheads per silo.

2. 44 remaining SS-18s used to replace as many early failures as

possible (20 percent of all missiles fail through second-stage

ignition and can potentially be replaced, and 5 percent fail

in latter portions of flight), bringing reprogrammed reliability up to 85 percent.

3. Height of burst for first-round airbursts is 1,600 ft. (140

scaled ft.).

4. Height of burst error of 20 percent, resulting in overall CEPs

for airburst weapons of 1,650 ft. (for 1,500 ft. missile CEP)

and 1,400 ft. (for 1,200 ft. missile CEP). Note: height of

burst error of zero would result in Minuteman survivability

of 41 percent for 1,500 ft. CEP and 27 percent for 1,200 ft.

CEP.

5. Minuteman silo hardness of 2,000 pounds per square inch; 550

pounds per square inch for Titan.

a/ Circular Error Probable,

b/ Equivalent megatons.
Figure B-3.

Surviving U.S. Minuteman Force:

90 Percent Confidence Intervals for Attack 3

Percent

100

90

80

70

60

50

40

30

20

10

0

Upper 90% Confidence Limit

Expected Value Hesult (from Table B-3)

Lower 90% Confidence Limit

1,500 feet 1,200 feet

Circular Error Probable of Soviet ICBMs

ASSUMPTIONS:

1. For groundburst weapons, SS-18 Circular Error Probable (CEP) varies from a lower limit of

1,300 ft. to an upper 90 percent confidence level of 1,800 ft. for 1,500 ft. CEP, and from

a lower limit of 1,000 ft. to an upper 90 percent confidence level of 1,500 ft. for 1,200 ft.

CEP. For airburst weapons, CEP varies from a lower limit of 1,450 ft. to an upper 90 percent confidence level of 1,950 ft. for 1,650 ft. airburst CEP, and from a lower limit of 1,200

ft. to an upper 90 percent confidence level of 1,700 ft. for 1,400 ft. airburst CEP.

2. For SS-18 yield, one standard deviation equals 300 kilotons.

3. SS-18 reprogrammed reliability varies from an upper limit of 90 percent to a lower 90 percent confidence level of 80 percent.

4 Minuteman silo hardness varies from an upper limit of 2,500 pounds per square inch to a lower

90 percent confidence level of 1,000 pounds per square inch.

65

II II

APPENDIX C. U.S. ICBM VULNERABILITY IN THE MlD-TO-LATE-1980s

In the latter half of the 1980s, the vulnerability of the

U.S. silo-based ICBMs may grow if the Soviets develop missiles

similar in payload and yield to the SS-18 but capable of accuracies of 900 to 600 feet. The following tables present the

results of hypothetical Soviet attacks using new generation, large

ICBMs, referred to here as "SS-18 follow-ons."

67

20-G94 O - 78 - '

mil
JLMJ IJJL 1L __.

TABLE C-l. ATTACK 1: ONE GROUNDBURST

Percent

Surviving U.S. ICBMs

Missiles Warheads EMT b/

With 900 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

26

26

8

118

144

4

266

118

432

4

554

118

132.6

17.3

268

With 600 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

9

9

4

41

50

2

93

41

150

2

193

41

46

8.7

96

ASSUMPTIONS:

1. 264 SS-18 follow-ons with eight 1.5 megaton warheads used in

attack. Two warheads, both programmed to groundburst, fired

at each U.S. silo. At most, one detonation per silo.

2. Reliability = 0.80; compounded reliability = 0.96.

3. Minuteman silo hardness of 2,000 pounds per square inch;

550 pounds per square inch for Titan.

a/ Circular Error Probable,

b/ Equivalent megatons.

68
Figure C-1.

Surviving U.S. Minuteman Force:

90 Percent Confidence Intervals for Attack 1

Percent

100

90

80

70

60

50

40

30

20

10

Upper 90% Confidence Limit

Expected Value Result (from Table C-1)

Lower 90% Confidence Limit

ASSUMPTIONS:

900 feet 600 feet

Circular Error Probable of Soviet ICBMs

1. SS-18 follow-on Circular Error Probable (CEP) varies -from a lower limit of 800 ft. to an upper 90 percent confidence level of 1,200 ft. for 900 ft. CEP, and from a lower limit of 500

ft. to an upper 90 percent confidence level of 900 ft. for 600 ft. CEP.

2. For SS-18 follow-on yield, one standard deviation equals 300 kilotons.

3. SS-18 follow-on compounded reliability varies from an upper limit of 99 percent to a lower

90 percent confidence level of 88 percent.

4. Minuteman silo hardness varies from an upper limit of 2,500 pounds per square inch to a lower

90 percent confidence level of 1,000 pounds per square inch.

69
.JUJ 111L

TABLE C-2. ATTACK 2: ONE AIRBURST, ONE GROUNDBURST

Percent

Surviving U.S. ICBMs

Missiles Warheads EMT b/

With 900 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

21

21

6

94

114

3

211

94

342

3

439

94

105

13

212

With 600 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

10

10

4

45

54

2

101

45

162

2

209

45

50

9

104

ASSUMPTIONS:

1. 264 SS-18 follow-ons with eight 1.5 megaton warheads used in

attack; cross-targeting of two warheads per silo.

2. Reliability = 0.80.

3. Height of burst for first-round airbursts is 1,600 ft.

4. Height of burst error of 20 percent, resulting in overall

CEPs for airburst weapons of 1,150 ft. (for 900 ft. missile

CEP) and 900 ft. (for 600 ft. missile CEP). Note: height of

burst error of 10 percent would result in Minuteman survivability of 17 percent for 900 ft. CEP and 7 percent for 600

ft. CEP.

5. Minuteman silo hardness of 2,000 pounds per square inch;

550 pounds per square inch for Titan.

6. 100 percent fratricide avoidance,

a/ Circular Error Probable.

b/ Equivalent megatons.

70
Figure C-2.

Surviving U.S. Minuteman Force:

90 Percent Confidence Intervals for Attack 2

Percent

100

90

80

70

60

50

40

30

20

10

0

Upper 90% Confidence Limit

Expected Value Result (from Table C-2)

Lower 90% Confidence Limit

900 feet 600 feet

Circular Error Probable of Soviet ICBMs

ASSUMPTIONS:

1. For groundburst weapons, SS-18 follow-on Circular Error Probable (CEP) varies from a lower

limit of 800 ft. to an upper 90 percent confidence level of 1,200 ft. for 900 ft. CEP, and from

a lower limit of 500 ft. to an upper 90 percent confidence level of 900 ft. for 600 ft. CEP.

For airburst weapons, CEP varies from a lower limit of 950 ft. to an upper 90 percent confidence level of 1,450 ft. for 1,150 ft. airburst CEP, and from a lower limit of 700 ft. to an

upper 90 percent confidence level of 1,200 ft. for 900ft. airburst CEP.

2. For SS-18 follow-on yield, one standard deviation equals 300 kilotons.

3. SS-18 follow-on reliability varies from an upper limit of 90 percent to a lower 90 percent

confidence level of 65 percent.

4. Minuteman silo hardness varies from an upper limit of 2,S>00 pounds per square inch to a lower

90 percent confidence level of 1,000 pounds per square inch.

71

Ml iirr
TABLE C-3. ATTACK 3: ONE AIRBURST, ONE GROUNDBURST, AND REPROGRAMMING FOR RELIABILITY

Percent

Surviving U.S. ICBMs

Missiles Warheads EMT b/

With 900 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

15

15

4

67

82

2

151

67

246

2

315

67

75.5

8.7

151

With 600 ft.

Soviet CEP a/

Minuteman II

Minuteman III

Titan

Total

5

5

3

22

27

50

22

81

1

104

22

24.9

4.3

51

ASSUMPTIONS:

1. 264 SS-18 follow-ons with eight 1.5 megaton warheads used in

first wave; cross-tairgeting of two warheads per silo.

2. 44 remaining follow-ons used to replace as many early failures

as possible (15 percent of all missiles fail through secondstage ignition and can potentially be replaced, and 5 percent

fail in latter portions of flight), bringing reprogrammed

reliability up to 90 percent.

3. Height of burst for first-round airbursts is 1,600 ft.

4. Height of burst error of 20 percent, resulting in overall

CEPs for airburst weapons of 1,150 ft. (for 900 ft. missile

CEP) and 900 ft. (for 600 ft. missile CEP).

5. Minuteman silo hardness of 2,000 pounds per square inch; 550

pounds per square inch for Titan.

6. 100 percent fratricide avoidance,

a/ Circular Error Probable.

b/ Equivalent megatons.

72
Figure C-3.

Surviving U.S. Minuteman Force:

90 Percent Confidence Intervals for Attack 3

Percent

100

90

80

70

60

50

40

30

20

10

Upper 90% Confidence Limit

Expected Value Rasult (from Table C-3)

Lower 90% Confidence Limit

900 feet 600 feet

Circular Error Probable of Soviet ICBMs

ASSUMPTIONS:

1. For groundburst weapons, SS-18 follow-on Circular Error Probable (CEP) varies from a lower

limit of 800 ft. to an upper 90 percent confidence level of 1,200 ft. for 900 ft. CEP, and

from a lower limit of 500 ft. to an upper 90 percent confidence level of 900 ft. for 600 ft.

CEP. For airburst weapons, CEP varies from a lower limit of 950 ft. to an upper 90 confidence level of 1,450 ft. for 1,150 ft. airburst CEP, and from a lower limit of 700 ft. to an

upper 90 percent confidence level of 1,200 ft. for 900 ft. airburst CEP.

2. For SS-18 follow-on yield, one standard deviation equals 300 kilotons.

3. SS-18 follow-on reprogrammed reliability varies from an upper limit of 95 percent to a lower 90

percent confidence level of 85 percent.

4. Minuteman silo hardness varies from an upper limit of 2,500 pounds per square inch to a lower

90 percent confidence level of 1,000 pounds per square inch.

73

I1T
_.J L
APPENDIX D. GLOSSARY I/

Antiballistic Missile (ABM) System; A system to counter strategic

ballistic missiles or their elements in flight trajectory.

Antisubmarine Warfare (ASW); Measures to detect, locate, track,

and destroy submarines, currently primarily dependent upon acoustic sensors.

B-52; The mainstay of the U.S. strategic bomber force since the

1950s. About 250 late model G and H aircraft and 75 rewinged D

bombers are expected to remain in the inventory until the early

1990s. Many of these will be equipped with cruise missiles in the

early 1980s, while others will continue to carry gravity bombs and

short-range attack missiles.

Ballistic Missile; Any missile which does not rely upon aerodynamic surfaces to produce lift and consequently follows a ballistic trajectory (that is, one resulting when the body is acted

upon only by gravity and aerodynamic drag) when thrust is terminated.

Circular Error Probable (CEP); A measure of the delivery accuracy of a weapon system used as a factor in determining probable damage to targets. It is the radius of a circle around

the target at which a missile is aimed within which the warhead

has a 0.5 probability of falling.

Counterforce Strike; An attack aimed at an adversary's military

capability, especially his strategic nuclear military capability.

Cruise Missile; A guided missile which uses aerodynamic lift

to offset gravity arid propulsion to counteract drag. The major

portion of a cruise missile's flight path remains within the

earth's atmosphere.

I/ Definitions are from SALT Lexicon, U.S. Arms Control and

Disarmament Agency, 1974; and from Projected Strategic Offensive Weapons Inventories of the U.S. and USSR, Congressional

Research Service, March 24, 1977.

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.ILMI

Cruise Missile Carrier (CMC); An aircraft capable of delivering

cruise missiles to within range of their targets. Current plans

call for the use of B-52 bombers in this role. In the mid-1980s,

wide-bodied commercial aircraft may be procured to supplement,

and eventually replace, the B-52 force.

Depressed Trajectory; The trajectory of a ballistic missile

fired at an angle to the ground significantly lower than the

angle of minimum energy trajectory. A method of reducing missile flight time.

Electronic Countermeasures (ECM); Measures used by bombers or

other aircraft to negate the effectiveness of enemy air defense

radars, surface-to-air missiles, and interceptor aircraft.

Equivalent Megatons (EMT); A commonly used measure of the urban

area destructive power of a. nuclear weapon that accounts for the

fact that area destructive power does not increase proportionately with increases in yield. It is expressed by the relationship EMT = N multiplied by Y to the 2/3 power, where N is the

number of weapons of yield Y.

FB-111; Medium bombers procured in small numbers in the late

1960s to supplement the B-52 force. Although capable of supersonic low-level flight, the aircraft's small range and payload

limits its effectiveness. Modified stretched FB-111H bombers

may be added to the bomber force in the 1980s.

First Strike (nuclear); The launching of an initial strategic

nuclear attack before the opponent has used any strategic weapons

himself.

Fratricide; The destruction of warheads entering an area where

previous nuclear explosions have recently taken place, especially

during a large-scale attack on a small area.

Generated Alert: A condition when forces are placed in a high

state of readiness, with the vast majority of the bomber force

on ground alert ready for rapid take-off and the vast majority

of the submarine force at sea.

Global Positioning Satellites (GPS); A system of orbiting satellites that will be able, to give ships, aircraft, missiles, and

other vehicles precise information on their position and velocity by the early 1980s.

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Hardness; The amount of protection afforded by structural shielding against blast, heat, and radiation effects of nuclear explosions, usually measured in pounds per square inch (PSI).

Inertial Guidance; A system that measures acceleration by means

of gyros and relates it to distances traveled in certain directions. Designed to steer ballistic missiles over predetermined

courses, using data generated solely by devices in the missiles.

Intercontinental Ballistic Missile (ICBM); A land-based, rocketpropelled vehicle capable of delivering a warhead to intercontinental ranges (ranges in excess of about 3,000 nautical miles).

Kiloton (KT); The yield of a nuclear weapon equivalent to 1,000

tons of TNT.

Megaton (MT); The yield of a nuclear weapon equivalent to

,000 tons of TNT.

Megato

1,000,(

Minuteman; The mainstay of the U.S. ICBM force since the early

1960s.At the present time, the United States maintains a force

of 450 single-warhead Minuteman II missiles and 550 three-warhead

Minuteman III missiles.

MK-12A; A higher yield, more accurate warhead designed to replace

the MK-12 warhead presently deployed on Minuteman III missiles.

MK-12A warheads may also be deployed on MX ICBMs and Trident II

SLBMs.

Multiple Independently Targetable Reentry Vehicle (MIRV); Two

or more reentry vehicles carried by a single missile and capable

of being independently targeted.

MX; A more powerful, more accurate ICBM now in the research and

development stage that may supplement the Minuteman force in the

mid-1980s. Current plans call for mobile basing for MX missiles.

Missiles would be moved either within underground protective

trenches or among protective above-ground shelters.

Payload; The weapon and/or cargo capacity of any aircraft or

missile system, expressed variously in pounds, in number of weapons, and in terms of missile warhead yields.

Polaris; U.S. submarines that carry the first generation of

submarine-launched Polaris missiles. Each submarine can carry 16

missiles. Expected to begin leaving the force in the early 1980s.

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Poseidon: U.S. submarines that carry the first generation of

multiple-warhead, submarine-launched Poseidon missiles. Each

submarine can carry 16 missiles. The thousands of warheads carried by these 31 submarines comprise the most survivable element

of the U.S. nuclear retaliatory capability. Expected to be replaced by Trident submarines during the late 1980s and early

1990s.

Reentry Vehicle (RV); That portion of a ballistic missile designed

to carry a nuclear warhead and to reenter the earth's atmosphere

in the terminal portion of the missile trajectory.

Seafarer; An Extremely Low Frequency (ELF) U.S. Navy communications system for submarines that would allow receipt of messages

without the necessity of bringing submarines close to the surface,

where they are most vulnerable. Presently in the research and

development stage, Seafarer could be constructed in the early

1980s.

Second Strike; A term usually used to refer to a retaliatory

attack in response to a first strike.

Silo; Underground facilities for a hard-site ballistic missile

and/or crew, designed to provide prelaunch protection against

nuclear effects.

Short-Range Attack Missile^ (SRAM); An air-to-surface missile

carried by U.S. FB-111 and B-52 bombers.

SS-18; A large Soviet surface-to-surface missile. The largest

ICBM in the world, the SS-18 can carry eight to ten megaton-range

warheads. Now being deployed, about 300 SS-18s may eventually

replace older, single-warhead SS-9s. Smaller SS-19s and SS-17s,

both multiple-warhead missiles, are currently replacing older,

single-warhead SS-lls.

SSBN; Nuclear-powered ballistic missile submarine.

Strategic Stability; Strategic stability encompasses both crisis

stability and arms stability, and refers to a relationship in

which neither side has an incentive to initiate the use of strategic nuclear forces in a crisis or perceives the necessity to

undertake major new arms programs to avoid being placed at a

strategic disadvantage.

Submarine-Launched Ballistic Missile (SLBM); A ballistic missile

carried in and launched from a submarine.

78
Surface-to-Air Missile (SAM); A surface-launched missile employed

to counter airborne threats.

Throw-Weight; Ballistic missile throw-weight is the maximum useful weight which has been flight tested on the boost stages of the

missile. The useful weight includes weight of the reentry vehicles, penetration aids, dispensing arid release mechanisms, guidance devices, reentry shrouds, covers, buses, and propulsion devices with their propellants (but not the final stages) that are

present at the end of the boost phase.

TRIAD; The term used in referring to the basic structure of the

U.S. strategic deterrent force. It is comprised of land-based

ICBMs, the strategic bomber force, and the Polaris/Poseidon submarine fleet. (Trident submarines will join the force in the

early 1980s.)

Trident; U.S submarines now under construction that are expected

to replace the Polaris/Poseidon fleet. Each submarine will be

able to carry 24 Trident I or Trident II missiles. The Trident II

missile, now entering research and development, will ptovide an

option to improve the accuracy and increase the destructive power

of the sea-based nuclear force in the mid-to-late 1980s.

Warheads; That part of a missile, projectile, or torpedo that

contains the explosive intended to inflict damage.

Yield; The force of a nuclear explosion expressed in terms of

the number of tons of TNT that would have to be exploded to produce the same energy.

79

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