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Defense Science Board 

Task Force Report on 

Science and Technology Issues of Early 

Intercept Ballistic Missile Defense

Feasibility

September 2011

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This report is a product of the Defense Science Board (DSB). The DSB is a Federal Advisory 

Committee established to provide independent advice to the Secretary of Defense. Statements, 

opinions, conclusions, and recommendations in this report do not necessarily represent the 

official position of the Department of Defense. 

The DSB Task Force on Science and Technology Issues of Early Intercept Ballistic Missile 

Defense Feasibility completed its information gathering in May 2011.

This report is UNCLASSIFIED and is releasable to the public.
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Table of Contents

Introduction and Summary............................................................................................................................ 7

Chapter 1: The Value of Early Intercept and the Ability to Achieve It........................................................... 9

Chapter 2: Key Attributes of Regional Ballistic Missile Defense................................................................. 24

Chapter 3: Critical Enablers for the Regional Defense Mission..................................................................26

Chapter 4: Costs and Cost Effectiveness ...................................................................................................29

Chapter 5: Findings and Recommendations...............................................................................................33

Appendix A: Terms of Reference................................................................................................................35

Appendix B: Task Force Membership.........................................................................................................37

Appendix C: List of Briefings.......................................................................................................................38

Appendix D: Briefers ...................................................................................................................................39

Appendix E: Acronyms................................................................................................................................40

List of Figures

Figure RMS-1: Ballistic Missile Dispense Times in Seconds.....................................................................10

Figure RMS-2: Kill Assessment Errors Must be Very Low to Provide Payoff............................................11

Figure RMS-3: EPAA Kinematic Coverage with Slower Missile................................................................. 13

Figure RMS-4: EPAA Kinematic Coverage with Faster Missile..................................................................14

Figure RMS-5: Pre-100-second Intercepts with Overly Optimistic Assumptions........................................15

Figure RMS-6: Coverage Achievable with Slow Missile and Netted Local Surveillance and Tracking......16

Figure RMS-7: Coverage Achievable with Fast Missile and Netted Local Surveillance and Tracking.......17

Figure RMS-8: Impact of Organic-only Operation .....................................................................................18

Figure RMS-9: Defense Coverage over Israel with Slower Missile ...........................................................19

Figure RMS-10: Defense Coverage over Japan with Slower Missile .........................................................19

Figure RMS-11: Potential Value of Regional Defenses in Contributing to Homeland Defense .................20

Figure RMS-12: Regional System Participation in Defense of CONUS with Nominal Fast Missile ..........21

Figure RMS-13: Full Regional S-A-S Coverage over CONUS with 40% Faster Missile in Land-Based 

Sites Only....................................................................................................................................................22

Figure RMS-14: Full S-A-S Coverage over CONUS with 20% Faster Missile in Both Sea-based and Landbased Sites..................................................................................................................................................23

Figure RMS-15: Traditional Ballistic Missile Defense Objectives ...............................................................24
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Introduction and Summary

The Defense Science Board Task Force on Science and Technology Issues of Early Intercept (EI)

Ballistic Missile Defense Feasibility was convened in December 2009 and concluded its deliberations in 

May 2011.

The Terms of Reference (TOR) for the Task Force focused on defense against regional-level adversary 

ballistic missiles. It directed the Task Force to consider both technology issues and architectural 

constructs to accomplish “Early Intercept” (defined in the TOR as that interval in a ballistic missile’s flight 

between thrust termination and final deployment of warhead(s) and/or countermeasures).

The complete terms of Reference are in Appendix A, and the Task Force membership is in Appendix B. 

A list of briefings to the Task Force is in Appendix C.

In February 2010, the Department of Defense issued a key document that comprehensively outlined the 

objective of the Nation’s ballistic missile defense program (Ballistic Missile Defense Review Report, 

February 2010). This document clearly spelled out the top priority role of regional ballistic missile defense 

wherein the U.S. committed itself to defend not only our military assets overseas, but also to provide 

missile defense assistance to our “allies and partners.” The U.S. has many allies and partners worldwide, 

so there is a wide range in the difficulty of achieving defensive coverage of their territories. The collection 

of allies in Europe represents the largest land mass to cover, and the Task Force devoted much of its 

analytics to this European theater. However, in examining the issues related to EI in the context of the 

Phased Adaptive Approach (PAA) in Europe (EPAA), the Task Force additionally considered a different 

kind of “EI” from that spelled out in the TOR, namely the issues related to using regional forward-based 

defenses to get an “early” shot at intercontinental ballistic missiles (ICBMs) heading to the U.S.

Chapter 1 of this report analyzes the benefits and shortfalls of the EI proposition. As a result of the 

analyses presented in Chapter 1, certain key attributes of effective Regional Defense became evident, as 

did some key enablers required to achieve an effective defense. Chapters 2 and 3 review those key 

attributes and technological enablers, respectively. The Task Force’s principal findings and 

recommendations are in Chapter 4.

Overall, we conclude that EI per se is not a particularly useful goal or protocol for design of a regional 

BMD system. There is often confusion as to what EI means; moreover, it is not fundamental as an 

attribute of effective ballistic missile defense. Far more useful are the more traditional objectives: 

• Large battlespace – to enable flexible firing doctrines such as shoot-assess-shoot (S-A-S)

and to reduce the defense sensitivities to varying offense tactics and threat details;

• Large defended areas – to obtain the economic benefit of having to deploy only a few sites 

instead of many, thereby reducing the number of defense assets, required interceptor missile 

inventories, and basing requirements

• High single-shot probability of kill – to minimize the number of interceptor firings required 

to achieve high probability of low leakage and also to guard against correlated errors 

minimizing the effectiveness of multi-shot firing doctrines. 

Each of these traditional objectives contributes to the robustness, quality, and affordability of regional 

defense, and they are fundamental to cost-effective ballistic missile defense. 

The critical enablers to achieve the objectives mentioned above are:
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• High missile velocity — fundamental to almost everything else. 

• The ability to launch defense interceptors early in the trajectory of enemy missiles. Radars of 

much more substantial operating range than the current radar on the Aegis ships will be 

necessary for the full realization of a robust regional defense. Modest improvements to current 

land-based radars also improve the defense capability against long-range regional threats. Newtechnology airborne and space sensors, capable of establishing high-accuracy tracks on 

offensive missiles early in flight, are promising.

• The efficient networking of sensor platforms and weapons is clearly mandated for the demanding 

European role. We show in Chapter 1 the serious consequence of relying solely on organic 

operation. 

• Although not analyzed in detail during the course of the study, it is clear that the successful 

operations of these components is predicated on an ability to discriminate (in the exo 

atmosphere) the missile warhead(s) from other pieces of the offensive missile complex, such as 

rocket bodies, miscellaneous hardware, and intentional countermeasures. The importance of 

achieving reliable midcourse discrimination cannot be overemphasized.

In our examination of the potential for forward-based regional assets to contribute to the defense of the 

U.S. against ICBMs, we find that such an intercept capability, early in the trajectory of incoming missiles, 

has the potential to both reduce the cost and increase the effectiveness of homeland defense. This 

potential, however, is highly dependent on the regional defense enablers discussed above, and in 

particular on achieving high velocity in our regional interceptors as well as on the ability to do effective kill 

assessment for the forward based intercepts. We also note that this potential is much less dependent on 

earlier interceptor launch (including even prior to enemy missile booster burnout) than from the other 

enablers such as high interceptor velocity.

Overall, the basic components in inventory now, namely Aegis ships with radars and long-range 

interceptor missiles, are well suited as the foundation of the regional defense mission, including the 

defense of Europe. The Task Force also finds that current efforts to place assets on land, where suitable 

geography and regional political relationships enable this option have the potential to contribute to and 

enhance a flexible and effective ballistic missile defense.
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Chapter 1:

The Value of Early Intercept and the Ability to Achieve It

Possible Value of EI

After much discussion and a number of briefings by MDA and others, the Task Force identified three 

potential areas in which EI, if achievable, might have considerable value.

• The ability to deny an adversary the use of penetration aids or early release of 

submunitions: While boost-phase intercept (currently not feasible) is a fundamental counter to 

either of these offense tactics, there could be some value in a post-boost intercept, provided it 

wasearly enough.

• The ability to achieve a S-A-S firing doctrine: If the first shot by the defense could be made 

early enough in the ballistic missile trajectory, sufficient time might remain to assess the lethality

of the first shot before firing an additional interceptor missile(s).As will be shown, a S-A-S firing 

doctrine offers the potential for cost savings by reducing required interceptors per enemy ballistic 

missile.

• The ability to achieve a large defensive footprint or area of protection: By a suitable 

combination of interceptor location and interceptor velocity, an intercept early in the offensive 

trajectory can cast a large defensive “shadow” – i.e., the azimuth and elevation spread of 

outgoing ballistic missiles heading to different targets will not have propagated very broadly, and 

thus a single defensive firing battery can protect a large ensemble of potential target areas.

In the sub-sections below we examine the requirements and caveats associated with each of these three 

possibilities, after which, using the EPAA as a representative situation, we examine the feasibility of 

realistic ballistic missile regional capabilities to achieve them.

Deny the Use of Penetration Aids or Early Release of Submunitions

One of the primary motivations for boost-phase intercept, despite our current inability to achieve it, is that 

the offense cannot either (a) confound the defense by releasing penetration aids or (b) create too many 

lethal targets for the defense to shoot at by releasing submunitions, until after the booster has burned out. 

This is fundamental, and no “trick” of the offense can violate this principle. Clearly the advantage to the 

defense of doing this does not disappear the instant burnout occurs, because it takes the offense some 

period of time to dispense whatever penaids or submunitions are to be released. So the question is, 

“What is this period of time?” In order to get a first-order estimate of this, i.e., is it seconds, tens of 

seconds, or hundreds of seconds, the Task Force reviewed dispense times for a variety of U.S. and 

foreign ballistic missiles, including both test articles and operational missiles. The results of this review 

are displayed in Figure RMS-1.

Four sets of data are presented. Above the line are data for foreign vehicles, and below the line for U.S. 

vehicles. In each set of data, the red figures represent the time at which the first objects were released 

and the red figures indicate the last release of objects. The blue shaded area depicts the first release of 

the various objects considered. 
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Figure RMS-1: Ballistic Missile Dispense Times in Seconds

If the benefit of the defense’s EI in countering release of ballistic missile penaids or submunitions is to be 

realized, then the defense must achieve its intercept, at the latest, within the time after burnout 

highlighted in blue. Based on the above, we have used a canonical time of 100 seconds post-boost as 

the measure of whether an intercept is early enough to provide this defense benefit. We note that, as 

stressing as this may be on the defense, it is the longest time that is available, and in many cases will be 

too long, as indicated by the fact that most of the first releases occurred well inside this time. In the 

footprint analysis below, we will examine the conditions under which intercepts can be achieved within 

100 seconds after enemy missile burnout.

Save defense missile assets with a S-A-S firing doctrine

In general, for realistic values of single-shot kill probability (Pssk), if the ballistic missile defense is to 

achieve low leakage, multiple shots will be required against each incoming enemy ballistic missile. For 

example, if the defense system can achieve a Pssk of 0.85 for each missile it shoots, and this statistic is 

independent shot-to-shot, achieving a 50% probability of no leakers against a raid of 30 tactical ballistic 

missiles (TBMs) will require the defense to shoot three missiles at each incoming TBM. In order to 

achieve a 90% probability of no leakers, four defense missiles must be devoted to each incoming offense 

missile. This obviously can become a very expensive requirement for the defense. If, as an alternative to 

simply firing salvos of defense missiles at each incoming missile, time is available to fire one missile, 

observe what happens from that engagement, and then fire the remaining missile(s) only if the 

assessment is made that the first shot was not successful, then the potential exists to save significant 

defense resources. For the Pssk of 0.85 that we used above, the probability that the first missile will not 

be successful is 0.15 (1-0.85) and thus only 15% of the time will the other missiles have to be fired. For 

the 0.5 probability of no leakage against the example of 30 TBMs, this would mean that instead of firing 3 

missiles on average, the defense would have to fire only 1.3 missiles (the first one and then another two 

15% of the time). This would represent a potential missile savings of 56%. For the 90% no leakage case 

above, the potential savings would be 64% (1.45 missiles instead of 4).
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But none of these potential savings can be achieved unless two criteria are satisfied:

1. The ability to make the first shot early enough (or alternatively, to make the last shot late enough) 

to leave sufficient time to observe the results of the initial shot before launching the subsequent 

missile(s). We note that it is the time available before the first possible and the last possible shot 

that is important – not necessarily the ability to shoot “early,” although this will certainly help. We 

call this time interval “battlespace,” and it is the all-important attribute in having the time available 

to do S-A-S.

2. The ability to keep the errors we make in the assessment of whether or not the first shot was 

successful sufficiently low. There are two types of errors that are possible – the error that 

although the first shot was unsuccessful the target is assessed as dead (false positive), and the 

opposite error that although the first shot was successful, the target is assessed as still alive 

(false negative). We note that while the false negative wastes defense missile resources (we 

shoot when we don’t have to), the false positive is far more critical – a live RV is still coming at us, 

and we let it come without further action. For this reason we generally set our decision criteria to 

minimize the false positive at the expense of the false negative (the two are linked by the physics

and statistics of the phenomenology). Figure RMS 2 provides one example of how well we must 

be able to assess whether or not we killed the target with the first missile if we are to save 

significant missile inventory. It is evident that an error of only a few percent in the probability of 

false positive makes the effort to achieve sufficient battlespace to enable S-A-S, whether through 

EI or not, not worth doing. Unfortunately, the ability to make kill assessments with such small 

probabilities of false positive has yet to be demonstrated.

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0

10

20

30

40

50

60

70

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08

Probability of false positive (calling a live target dead)

Interceptor Savings (%) over Equivalent Salvo Fire

Not worth 

doing

Worth 

doing

Pssk = .85

# tgts = 30

False Neg = 10X False Pos

Figure RMS-2: Kill Assessment Errors Must be Very Low to Provide Payoff
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Protect large defended areas by making intercepts early in the ballistic missile trajectory

This is sometimes called casting a large defended “shadow.” It comes about from the fact that early in 

their trajectories RVs from the same launcher heading to widely separated targets will not have spread 

far, since the time over which their different velocity vectors have propagated is short. Thus, a single 

interceptor launch position – given that it is close enough to the offense launch position and contains 

defense missiles of sufficient velocity – can protect a large area behind it. This has a defended coverage 

benefit in and of itself. However, to also get the efficiency benefit of S-A-S discussed above, once again 

the real issue is battlespace – i.e., the ability to make intercepts both early and late. 

In the remaining sections of this chapter we examine the ability to protect the large areas implied under 

the latter phases (Phases 3 and 4) of the EPAA. This will provide a means of examining both the 

difficulty of achieving EI in a regional context, as well as the value of achieving it in each of the three 

potential payoff areas discussed above.

Assessing the feasibility and actual payoff of EI in achieving penaid denial, S-A-S, and large 

defended areas in EPAA

The Task Force examined the area of protection that could be achieved in the latter phases of EPAA as a 

function of four different EI conditions, listed in order of decreasing difficulty:

1. Early enough to achieve denial of early release of submunitions or penaids – this was defined as 

intercepting no more than 100 seconds after threat burnout.

2. Early enough to provide sufficient battlespace to enable an S-A-S firing doctrine. We assumed 

that the assessment phase could be accomplished within 20 seconds after intercept

3. Early enough that a salvo firing doctrine (i.e., firing two or more missiles in close succession) 

could provide at least one intercept opportunity within the pre-apogee flight regime.

4. No EI constraint – ability to provide salvo intercepts unconstrained by the criterion of #3 above.

Surveillance Unconstrained, Kinematic Coverage in Europe

Figure RMS 3 represents one such examination. The map shows the defended area in five different 

colors (the fifth being “uncovered” or no defense coverage possible) as a function of each of the EI

definitions above. The colors are ordered in terms of potential benefit to the defense.1

 

1 We include whether before or after apogee as a criterion as a matter of interest. However, we note that there is no identified 

specific advantage or disadvantage of intercepting before or after apogee respectively. It’s an arbitrary measure.

 The zones are 

constructed to be defense enforceable, i.e., we assume that the adversary can attack from any place 

within his country and an area is considered “defended” if and only if all of the attack trajectories can be 

intercepted prior to getting to their intended target area. Four defense sites contribute to the defense --

three on ships as shown and one on land in Eastern Romania. Each site contains generic advanced SM3 missiles with a burnout velocity that we will characterize here as “slow.” The assumption is made that 

the defense can launch missiles 100 seconds after threat booster burnout – this being a representative 

time to establish the threat state vectors with sufficient accuracy such that the initial missile heading 

errors can be taken out within the divert capability of the later stages of the interceptor. Using this 

definition regarding when the defense can launch, no surveillance sensor detection or tracking constraints 

are included- i.e., we assume a defense interceptor launch at enemy booster burnout plus 100 seconds 

without any regard to whether or not this is possible with realizable surveillance sensors -- we will 

examine the impact of real surveillance in association with figs RMS 6, 7 and 8 below... 

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Figure RMS-3: EPAA Kinematic Coverage with Slower Missile

We see in RMS-3 that good coverage of most of Europe is achievable, and even some small pockets of 

S-A-S just behind each of the firing batteries is possible, although none of the three “EI” benefits is widely 

achievable. In particular, it is not surprising that the penaid benefit (intercept less than 100 seconds after 

burnout) cannot be achieved, since the defensive missiles are not launched until this time.

Fig RMS-4 shows the same case but with a significantly faster missile in the land-based site. The faster 

missile, even in the single land-based site, buys enough time to now enable S-A-S over nearly the entire 

region. Note that we also see a small area of pre-apogee salvo west of the UK, where there is not 

sufficient battlespace to achieve S-A-S, even though at least some of the salvo shots are sufficiently early 

to achieve intercepts prior to apogee2

 

2 See Footnote 1.

. This is the only case we saw in which pre-apogee salvos had a 

zone somewhat larger than the S-A-S zone. Thus, in general, achieving a pre-apogee intercept shrinks 

the coverage zone beyond the more beneficial S-A-S zone. This also underscores the fact that S-A-S is 

more a function of available battlespace than EI per se. 
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Figure RMS-4: EPAA Kinematic Coverage with Faster Missile

The difficulty in achieving intercepts within 100 seconds of burnout

We noted above our assumption that not launching the interceptor until 100 seconds after enemy booster 

burnout fundamentally eliminated any possibility of achieving intercepts inside this timeline. The Task 

Force explored the degree to which a more optimistic set of defense conditions might lead to at least 

some pre-100-second intercepts over the coverage region. Fig RMS-5 below is one example of what it 

might take to get even minor coverage in the region.

To achieve even the very limited pre-100-second coverage in the figure, a number of extremely optimistic 

defense assumptions were made – both on what could realistically be assumed with greatly advanced 

missile technology and with dramatic changes in the political environment in the region to allow the 

defense deployment to essentially surround the launch areas. These assumptions included:

• Deploying two sea-based (one in a land-locked body of water) and two land-based firing batteries 

sitting immediately outside the adversary’s territory. All contain the very high velocity missiles 

described below.

• The ability to launch the defense interceptor immediately at enemy booster burnout. If possible at 

all, this would take significant effort, both in sensor technology and in deployment, as well as in 

the divert capability of the missile.

• Intercept burnout velocity nearly 70% greater than the “fast” interceptor used in RMS-4 above, 

together with an interceptor burn time about 1/3 that of the fast missile – again, taken together 

these are near-impossible conditions.
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Figure RMS-5: Pre-100-second Intercepts with Overly Optimistic Assumptions 

From these analyses, the Task Force concluded that achieving a useful area of protection over which 

intercepts could be made within 100 seconds after enemy booster burnout was essentially impossible. 

Again, from the missile data we reviewed, in most cases 100 seconds is too late – to effectively negate 

early release of penaids or submunitions, intercepts would have to be achieved well inside this timeline.

Surveillance Considerations in EPAA

The Task Force next investigated the required sensor capability to support the kinematic coverages 

achieved with the slower and faster missiles shown in Figures RMS-3 and RMS-4, respectively. Figure

RMS-6 shows the defense coverage for the slower missile, including sensor limitations, for the sensor 

suites discussed below. The objective was to provide a “balanced” capability that matched the kinematiconly coverage in Fig RMS-3 – e.g., a construct in which the required sensor capabilities just support the 

kinematics of the missile.
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Figure RMS-6: Coverage Achievable with Slow Missile

and Netted Local Surveillance and Tracking

With advanced local sensors at all four firing batteries, as well as a larger sensor forward based in 

Eastern Turkey, the kinematic coverage depicted in RMS-3 can be fully supported – i.e., the coverage 

shown in figure RMS-6, in which interceptor launch is dependent upon sensor detection and track, is 

essentially the same as that in RMS-3. 

The shipboard radars were assumed to be of the type and size for which the Navy is currently conducting 

competitive concept formulation and risk reduction studies to support advanced Aegis surveillance and 

fire control. The radar supporting the land-based firing battery is identical to the existing Army fire control 

radar for THAAD. The larger forward-based early warning, detection, and tracking radar is similar to the 

land-based fire control radar, but is larger in the product of gain, aperture, and power by a factor of 3 (5 

dB). This measure of radar capability is appropriate, since it is assumed that because satellite cueing is 

available to aid in detection, track rather than search is the dominant requirement. This 3X factor could 

be achieved with an array size about 40% greater in area than the current configuration. Whether this is 

feasible or not was not investigated by the Task Force, although it certainly seemed that an array that 

was about 20% greater in both dimensions was within the realm of feasibility. It is important to note the 

assumption that all of these radars were fully netted, including their connectivity to satellite surveillance 

for cueing purposes. This presumption that high-quality track data were available wherever and 

whenever it was useful enabled the employment of both launch-on-remote and engage-on-remote fire 

control. We will see in a subsequent discussion the significant sensitivity of these results to that 

oversimplifying assumption.

The Task Force further investigated whether these same sensor capabilities had the ability to support the 

kinematic coverage achieved with the faster missile depicted in Figure RMS 4. Figure RMS-7 below 

depicts the coverage obtained with the same local sensors as discussed above in relation to RMS-6, but 

with the addition of a second land-based firing battery in Poland. This additional firing battery was 
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required to preserve the large kinematic S-A-S coverage area shown in RMS-4.. With interceptor launch 

at booster burnout plus 100 seconds, (the condition in RMS-4) the faster missile in the single land-based 

site in Romania was adequate to provide battlespace over the entire region sufficient to allow subsequent 

shots after the “assess” period from both that same site, as well as from the sea-based sites, with the 

slower missiles. But under the condition of launching 100 seconds after ballistic missile detection by the 

sea-based or land-based sensors in situations in which detection occurred after booster burnout, (i.e., 

interceptor launch could not occur until more than a hundred seconds after booster burnout), the single 

land-based site with the faster missile could not project enough battlespace for S-A-S over the entire 

region, even with the large forward radar in Turkey. For some adversary launch sites the Poland battery 

offered protection of the northern areas of Europe, unachievable without it. 

Figure RMS-7: Coverage Achievable with Fast Missile and

Netted Local Surveillance and Tracking

The Criticality of the Robust Netting That Has Been Assumed

Throughout all of the above, the assumption has been made that the data collected by any sensor can be 

available with low latency and high quality to any other sensor, fire control function, or missile, whether on 

launch or in flight -- in other words, a perfectly netted regional BMDS system. It is therefore important to 

ask how critical this regional sharing of data is to obtaining the large defended areas shown in the 

preceding figures. The answer is “extremely.” Fig RMS-8 shows the results of the same defense 

laydown as in Fig RMS-7 (three sea-based sites with the slower missile, two land-based sites with the 

faster missile, and a forward-based large radar in eastern Turkey). All of the individual radar and missile 

capabilities are the same as in the robust S-A-S coverage of RMS-7, but all networking has been disabled 

and each site is working organically – i.e., it cannot launch a missile or send updates to it in flight except 

based on data it collects with its organic radar. The result is startling – not only has all of the S-A-S 

coverage disappeared, but most of the salvo coverage has disappeared as well. The only areas of 

protection left are small defended areas behind each of the land-based firing batteries – i.e., those with 

the fast missiles. The slower ship-based missiles cannot provide any area of protection, because without 
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cueing from some source, their on-board radars do not provide enough time to get to the RV either before 

the ship is overflown or before the RV gets to the ground. This is remedied to a degree with cueing, but 

without some kind of dependable real-time connectivity even timely cueing is not possible. Note this result 

occurs even assuming the organic radar upgrades previously described are implemented.

Figure RMS-8: Impact of Organic-only Operation

Capabilities in Mid-East and South East Asia Theaters

Figures RMS 9 and 10 indicate the defense coverage that can be obtained over Israel and Japan for 

attacks from potentially hostile neighboring countries. As is evident from the figures, country-wide 

coverage is much easier to obtain than in Europe, given the much smaller expanse of either of these 

countries as compared to all of Europe, and the relatively shorter range (lower velocity) of the attacking 

missiles. In both cases, complete coverage can be obtained with the slower advanced SM-3 family 

missile. In Israel, the single ship is aided by a sensor on land, about the size of the existing U.S. landbased radar supporting THAAD. Together they provide the salvo coverage shown. Because there is no 

opportunity to provide sensor basing closer to the shooter, a larger sensor (about +5 dB) is required to 

project S-A-S over the entire country. 
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Figure RMS-9: Defense Coverage over Israel with Slower Missile

In Japan, two ships between the shooter and the area to be protected provide complete coverage, with 

S-A-S over the most populated area. If increased S-A-S coverage were desired over most of the country, 

a third ship would be required, with the two shown in the figure redeployed somewhat.

Figure RMS-10: Defense Coverage over Japan with Slower Missile
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Potential Benefit of Forward-Based Regional Defenses in Supporting U.S. Homeland Defense

The Task Force also examined a somewhat different kind of “EI” than described in the Terms of 

Reference – the ability of forward-based regional defenses, as in Phase 4 of EPAA, to aid in the defense 

of the United States. The incentive for doing so is clear – not only does this present an opportunity for 

additional engagements beyond those possible with U.S.-based Ground-Based Interceptors (GBIs), but if 

the regional intercepts were early enough, there could be an opportunity to assess the results of the 

regional intercepts prior to committing the far-more-expensive GBIs. With a significant cost ratio between 

the GBI and the regional missile, this could provide a huge economic advantage. Fig RMS 11 quantifies 

this potential for the representative situation indicated in the figure.

At the assumed 0.8 Pssk effectiveness of the homeland defense GBI-like interceptor, three shots in salvo 

provide about a 90% probability of no leakers against a 10-missile attack3

1. Some fraction of the time the forward missiles kill the target and, given time to assess the results, 

only they are fired. The GBI missiles are not fired, thereby reducing the number of GBIs required; 

. If we now introduce a regional 

missile system, forward of the GBI, that takes two early shots against each ICBM heading toward the 

U.S., two things happen:

2. For the remaining cases, the regional missiles do not kill the target and the homeland defense 

missiles are fired.

4

Figure RMS-11: Potential Value of Regional Defenses in Contributing to Homeland Defense

 

3 We assume that a regional adversary has fewer ICBM class missiles than the shorter range ones useful in regional conflicts. 

Thus, although in the earlier part of this section we analyzed 30 missile regional attacks, here we believe 10 missile attacks are 

more representative of the ICBM situation.

4 The specific number of homeland defense missiles fired is a function of the Pssk of the forward based regional missile. In the 

curves, the number is chosen to maintain a fixed 0.9 probability of no leakers.
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This results in an overall savings of missile expenditures, the specifics of which depend upon two 

variables – the single shot kill probability of the regional missile and the ratio of unit cost between the 

rearward GBI missile and the forward regional missile (the blue, red and green curves in the figure). 

What is significant is that even the combination of a relatively low regional defense effectiveness 

(e.g., 0.4) against ICBMs and a relatively low cost ratio between the two kinds of missiles (e.g., 3:1) has 

the potential to cut the missile expenditure cost in approximately half. Two questions, of course, remain: 

can we achieve the very low kill assessment errors required to enable these kinds of cost savings? And 

can the regional defense system, and in particular the missile, provide this early shot capability? Figures 

RMS-12, 13 and 14 provide some insight into this latter question.

Each of the figures color-codes CONUS with five different defense capabilities: pink - no forward (i.e., 

EPAA) or rear (i.e., GBI) intercepts are possible; blue - only the forward regional intercepts can be made; 

yellow - only rear GBI intercepts can be made; light green - both forward and rear intercepts can be 

made, but only in a salvo (this situation did not occur in any of the three charts below); and dark green - 

the most favorable situation in which the forward regional missile can intercept with sufficient time to allow 

an assessment before launching the GBIs. We are interested, of course, in obtaining as much dark green 

as possible. As can be seen in Figure RMS-12, regional intercepts can take place only for those missiles 

heading into a small area in the northeastern U.S. This occurs because those trajectories travel closest 

to the regional defense land-based launch sites in Eastern Europe. As the target areas move 

southwesterly across the U.S., their corresponding trajectories over Europe move more northerly – 

trajectories from Iran into southern California go almost due north over the interior parts of Russia. 

These are too far from the regional land-based fast-interceptor launch locations to be intercepted. We 

also notice that the small bit of joint coverage over Maine that does occur provides sufficient time for the 

GBI launches to wait until after the regional missile intercepts have occurred – i.e., there is no significant 

light green area outside of the dark green Thus, at least in this limited case, if the forward intercepts can 

occur at all, they occur with sufficient time to enable S-A-S. We shall see below what is required to get 

joint coverage over the entire CONUS land mass and whether or not the conclusion holds up that 

wherever the regional missiles can get a shot at all, they can provide S-A-S capability.

Figure RMS-12: Regional System Participation in Defense of CONUS with Nominal Fast Missile
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Figure RMS-13 shows the S-A-S joint coverage that can be obtained with a slightly greater than 40% 

increase in the Vbo of the regional land-based missiles in Romania and Poland. As the Vbo of the landbased missiles increases from the nominal “fast” missile to the 40% increase discussed here, the S-A-S 

coverage over CONUS increases from that depicted in Figure RMS-12 to that shown in Figure RMS -13. 

The southwestern edge of the green area moves linearly with velocity in a southwest direction across the 

country until, at a 40% increase, all of CONUS is covered. We also examined the sensitivity of the 

required velocity to assumptions about when a defensive launch could take place (i.e. sensor 

effectiveness). The required velocity turned out to be relatively insensitive to launch timing. Over the 

range of 50 seconds before enemy missile burnout to 100 seconds after burnout, the interceptor velocity 

required varied only by about 0.3 km/sec, for a sensitivity of 0.1 km/sec per 50 seconds of launch timing. 

Thus, advanced search-and-track sensor technology, although useful for other purposes, cannot 

significantly ease the regional interceptor kinematics required to participate in this homeland defense 

mission.

Figure RMS-13: Full Regional S-A-S Coverage over CONUS with 40% Faster Missile in Land-Based 

Sites Only

If, instead of restricting the faster missile to land-basing only, the faster missile is based on both sea and 

land (all of the five locations shown in Figure RMS-7: Baltic, northern Mediterranean, eastern 

Mediterranean, Romania, and Poland) the required increase in Vbo over the nominal fast regional missile 

can be cut in half to about a 20% increase in Vbo, a more realistic option.5

 

5 In fact, the required missile velocity is quite sensitive to basing. For instance, if instead of a 3rd site on a ship in the Baltic, the 

basis for figure RMS-14, the 3rd site were on land further north and west in Europe, such as in Vardo, Norway, the 20% additional 

velocity could be reduced to about 14%.

 The S-A-S coverage provided 

with this missile in all European locations is shown in Figure RMS-14, almost duplicating that shown in 

Figure RMS-13 with the 40% faster missile. Note that in both cases, no forward and rear salvo-only 

coverage is provided – in other words, the general condition holds that if the forward regional missile can 

get a shot at all, the shot is early enough to provide sufficient time for an S-A-S doctrine, potentially 

saving considerable missile resources, provided that robust kill assessment is feasible. In addition, we 
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found the same interceptor velocity sensitivity to launch timing as in the land-based-only situation – 

namely about 0.1 km/sec Vbo per every 50 seconds of pre- or post-boost launch timing.

Figure RMS-14: Full S-A-S Coverage over CONUS with 20% Faster Missile

in Both Sea-based and Land-based Sites

Conclusions Regarding the EI Value Proposition

Based on the analyses reviewed in this chapter, some summary conclusions emerge:

1. In a regional context there is little measurable value in achieving EI per se.

a. A determined adversary can deny the potential benefit of intercepting missiles before 

they can dispense their lethal munitions or penaids.

b. Although there is potential value in enforcing a S-A-S firing doctrine, the ability to do so is 

dependent on large battlespace, not EI. Further, the value is dependent on performing 

robust kill assessment, and the ability to do so has yet to be established.

c. There is value in achieving large defended areas, but doing so is a function of scenario 

geometry, fast missiles, capable sensors, and robust networking. The imposition of an 

“EI” on top of these actually reduces the area of protection over the non-constrained case

(see discussion of pre-apogee salvo zone in association with Figure RMS 4). 

2. In a homeland defense context, there is a significant potential cost and effectiveness advantage of 

achieving an intercept by forward-based regional assets prior to having to commit rearward 

homeland protection assets such as GBIs. However, just as in the regional case, robust kill 

assessment is a crucial enabler. In addition, the feasibility of achieving the very high regional 

missile burnout velocity, depending upon siting, far in excess of what has currently been 

achieved, to provide this benefit over a large portion of the U.S. is uncertain. Finally, the 

performance benefit of earlier forward based intercept launch of the interceptor (e.g. even prior to 

booster burnout) in this scenario was minimal compared with the benefit of achieving a very high 

regional missile burnout velocity. 

3. Aside from these negative or qualifying comments on EI as a fundamental performance goal, it 

would appear that the feasibility of achieving the basic objectives of the PAA has been well 

established by the current and planned MDA program – no fundamental roadblocks or major 

technical barriers to success were uncovered by the Task Force.
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Chapter 2:

Key Attributes of Regional Ballistic Missile Defense

Certain characteristics of BMD systems have long been held as very important measures of overall 

effectiveness. Among these are large defended areas, high single-shot probability of kill (Pssk), and 

large battlespace (that is, a long time over which target complexes can be observed and evaluated and 

during which successive engagements can be made). The analyses performed by the Task Force – 

summarized in Chapter 1 and based on European regional defense and the potential regional contribution 

to U.S. homeland defense, with basic analyses of the defense of Israel and defense of Japan – confirm 

these beliefs.

Figure RMS-15 illustrates the benefits of these characteristics for the EPAA scenario discussed in 

Chapter 1. This analysis computes the number of defensive interceptor missiles required to enforce a 0.9 

probability of no leakers against a raid of 30 offensive missiles. We assume perfect exo-atmospheric 

discrimination of warheads from other objects, and, in the case of a S-A-S firing doctrine, an S-A-S error 

probability of false positive of 1% and false negative of 10%.

Three Traditional Objectives Provide 

Meaningful Value and Cost Avoidance

0

100

200

300

400

500

600

700

800

Number of Defense Missiles Required

6 Sites

0.75 Pssk

Salvo Only

4 Sites

0.75 Pssk

Salvo Only

4 Sites

0.85 Pssk

S-A-S Enabled

4 Sites

0.85 Pssk

Salvo Only

Larger Footprint

Permits Fewer Sites

Higher Pssk

Reduces Salvo Size

Bigger Battlespace

Enables S-A-S Doctrine

Prob No Leakers = 0.9

Raid Size = 30

S-A-S Error = 1%

Note: Perfect Exo Discrimination Assumed

75%

Savings

Figure RMS-15: Traditional Ballistic Missile Defense Objectives

Four hypothetical cases are considered. In the first case we assume the defense consists of six sites, 

each containing interceptor missiles with a 0.75 Pssk and with insufficient battlespace to enable an S-A-S 

firing doctrine. In order to achieve a 90% probability of no leakers with a 0.75 Pssk interceptor, 

statistically 4.1 interceptors must be salvo’d against each incoming missile. Since the defense must be 

able to withstand a 30-missile attack on whatever targets or critical areas the offense chooses to shoot at, 
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the total number of interceptors required at each interceptor location is slightly over 120 (30 potential 

incoming missiles times 4.1 interceptors per missile). Because we don’t know how the adversary may 

distribute his attack (spread over 30 different targets, all allocated to one high-value target, or anything in 

between), we must stock this number of missiles at all 6 launch locations, for a total of 738 interceptor 

missiles as shown in the bar.

In the second case we assume that each site can defend a 50% larger area on the ground. Other 

assumptions remain unchanged from Case 1. In Case 2 only four sites are necessary, and, although the 

number of interceptors required at each launch location remains the same (slightly over 120), they are 

required at only four locations instead of six, for a total of only about 492 interceptor missiles.

In the third case we assume that each interceptor missile is of a higher quality and is characterized by a 

Pssk of 0.85. Other assumptions remain unchanged from Case 2. The higher Pssk reduces the size of 

the salvo required to enforce the 0.9 probability of no leakers from 4.1 interceptors per incoming missile to 

3. Thus, only 90 interceptors are required at each launch location for a total of only 360.

In the fourth case we assume that the defense systems have both the kinematics and the long-range 

sensing to provide a significantly larger battlespace, which in turn enables the defense to employ an 

S-A-S firing doctrine. Other assumptions remain unchanged from Case 3. On average, only 1.6 

interceptors are required for each incoming missile, instead of the 3 required in the salvo case, and the 

larger battlespace and associated S-A-S firing doctrine reduces the number of interceptor missiles almost 

in half, to about 190.

Thus, the combination of these three fundamental factors or measures of effectiveness – larger defended 

area per site, higher Pssk, and battlespace sufficient to permit an S-A-S firing doctrine – combine to 

provide a 75% reduction in the number of missiles that are required in the defense laydown. 

What is important here is not necessarily the particular numbers and assumptions used in this section, 

but rather the fact that these three traditional measures of defense “goodness” provide a powerful impact 

on one of the most important affordability factors in missile defense – the number of interceptor missiles 

that must be procured for a given level of effectiveness. Thus, they provide meaningful and measurable 

objectives and should remain high in the focus of missile defense requirements vice the broad goal of 

achieving “EI”.
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Chapter 3: 

Critical Enablers for the Regional Defense Mission

The performance results described in Chapter 1 are predicated on four main defense system attributes:

• Fast missiles

• Long-range radars with precision tracking

• Reliable defense discrimination of threat objects

• Effective networking of defense assets across wide areas.

1. Fast Missiles

The planned progression in development of the SM-3 family interceptor missiles involves higher 

speed as a continuing improvement over subsequent generations of the missile. The value of 

higher speed in terms of regional defense area coverage and the ability to achieve the large 

battlespace required for S-A-S is illustrated in Figure RMS-7 (in comparison with Figure RMS-6) of 

Chapter 1. This evolution toward faster missiles is a key element of the European regional defense 

mission. In addition, the ability for regional defenses to participate in the defense of the U.S. 

homeland by forward engagement of adversary ICBMs is also critically dependent on high speed 

interceptors. This is illustrated in Figures RMS-12 and RMS-13. Importantly, the requirement for 

fast interceptor speed is not significantly reduced by Herculean efforts to launch close to, or even 

prior to, ballistic missile burnout; as discussed in Chapter 1, there is minimal performance gain in 

earlier regional interceptor launch for the S-A-S U.S. homeland scenario.

2. Long-Range Sensors

The current Aegis shipboard radar is inadequate to support the objective needs of the EPAA 

mission. For this reason, the TPY-2 land-based radars and the future Navy ship-based Air and 

Missile Defense Radar (AMDR) upgrade become critical components of the European defense 

scenarios (Section 1 Figure RMS-6 and associated discussion). In some situations, even the 

TPY-2’s superior tracking range is not adequate for a robust defense, and a moderate increase in 

sensitivity would be very useful (Chapter 1, Figure RMS-7, and associated discussion).

Radar technology has progressed significantly since the design of the Aegis radar in the 1960’s. 

The current development of a replacement for the Cobra Judy ship-based radar is clear evidence 

that shipboard radars of much longer range capability are feasible. The challenge for an advanced 

missile defense shipboard radar will be to accommodate the long-range detection and tracking 

needs to support a robust PAA, wherever it may be required in the world, while fitting within the 

volume, weight, and power constraints of both back-fit and new Navy combatant platforms. The 

Navy’s AMDR program is the only program solely focused on that challenge. Continued effort must 

be made in the years ahead to continue to develop advanced missile defense shipboard radar. 

Currently, the MDA is engaged in development of the Airborne Infrared (ABIR) sensor for ballistic 

missile threat detection, tracking, and possibly discrimination. This concept, although potentially 

promising as a component that would fit in well with a variety of missile defense architectures and 

regional situations, is in early development and not ready for inclusion in near-term plans for PAA 

architectures. At the time of this writing, the technical challenges include achieving highly accurate 
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angular accuracy for the sensor as well as the packaging (e.g. form factor) to employ on an 

operational (unmanned) air platform. The Task Force notes the great potential of this capability. 

Space also plays an important role in the process of detecting and tracking adversary missiles prior 

to launching an interceptor. While ground-, air-, and sea-based sensors provide the current tracking 

capability, their performance is often limited by geography and political constraints. Overhead 

Persistent Infra Red (OPIR) sensors can provide the initial detection capability when connected to a 

robust Command and Control, Battle Management and Communication (C2BMC) infrastructure. 

These sensors support and enable the BMDS to initiate the engagement process early and to cue 

downstream sensors to the missiles’ position and velocity. The sensors on the Space Tracking and 

Surveillance System (STSS) demonstration satellites have demonstrated fire-control quality 

tracking data for engagement of threat reentry vehicles and when combined with radar data, will 

provide improved threat object discrimination. Once fielded, the Precision Tracking Space System 

(PTSS) should provide a persistent, near-global tracking capability. 

In order to take full advantage of the OPIR cueing capability, additional elements of the space 

architecture must be completed. The highest precision cues can be accomplished by fusing Space 

Based Infrared System (SBIRS), other OPIR sensor data and radar data together; though this has 

been demonstrated in test environments, the BMDS Overhead Architecture ground system needs 

to be implemented in order to provide this capability in the operational system. Also, the Joint 

OPIR Ground architecture initiatives are needed in order to fully collect, process and integrate the 

data provided by the OPIR sensors. Finally, OPIR supports missions other than missile defense to 

include missile warning, battlespace awareness, and tactical intelligence; a community-wide OPIR 

concept of operations needs to be developed that addresses all stakeholders’ needs. 

3. Threat Discrimination Capability

The analysis of European regional defense in Chapter 1 and the missile resources analysis in 

Figure RMS-15 in Chapter 2 were both predicated on a robust ability for the U.S. defender to 

identify the offensive warhead in a background of missile booster bodies, separation hardware, and 

possible countermeasure objects such as decoys. These analyses accounted for defense 

interceptor reliability failures and the statistical probability of an interceptor miss; they did not 

account for interceptors launched at non-warhead bodies. If the defense should find itself in a 

situation where it is shooting at missile junk or decoys, the impact on the regional interceptor

inventory would be dramatic and devastating!

In the previous chapter we discussed the fact that large protected area and large battlespace were 

important attributes of robust missile defense. Unfortunately, those two attributes require intercepts 

outside the atmosphere, and if high single-shot probability of kill (the third important attribute in 

section 2) is going to be realized, then exo-atmospheric discrimination is necessary. Yet

discrimination in the exo-atmosphere is still not a completely solved problem. Robust research and 

testing of discrimination techniques must remain a high priority. 

4. Effective Networking

All of the Task Force analysis of future regional missile defenses was predicated on the effective 

networking and low-latency transfer of information among the various components of the defense – 

components that are deployed on land, on sea, in the air, and in space and spread over a 

continent-size, and in some cases, multi-continent-size, and piece of the earth’s surface.
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Without low-latency networking, the defense capability would be sorely restricted, and the large 

areas of protection depicted in Chapter 1 in Figures RMS 6 and 7 would be reduced to the small 

local areas of protection shown in Figure RMS 8. Lacking effective networking, the only way the 

defense could compensate would be to increase the range of sensors and the speed of missiles, as 

well as their associated inventory on both land and sea, to unrealistic and impossible-to-afford 

levels. 

Thus, robust networking is the only realistic protocol to achieve operationally useful, large-area 

defense coverage, effectiveness, and fire power for regional missile defense. In terms of future 

technology needs, adversary efforts to defeat, disrupt, and/or deny such networking need to be 

anticipated, mitigated, and protected against. 
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Chapter 4

Costs and Cost Effectiveness

While the Task Force did not conduct a comprehensive review of BMDS costs, our analyses nevertheless 

reveal the potential for EI to provide more cost-effective BMD insofar as it can contribute to reducing the 

number of interceptors needed/expended in both regional and homeland defense scenarios.

We will use these two defense scenarios—regional and homeland defense--to illustrate the potential cost 

savings that could be achieved. In Chapters 1 and 2, we identified opportunities for relative cost savings 

measured in reduced numbers of interceptors which might be achieved through enabling effective 

opportunities for S-A-S6

Focusing on differences in interceptor costs is appropriate because, to counter multiple missile raids with 

a high probability of no leakers, large numbers of interceptors will need to be expended. We anticipate 

that differences in interceptor costs will dominate differences in the costs of other components of the total 

BMD system.

in the context of EPAA. In particular, in Figure RMS-2 we analyzed the results for 

using a higher VBO, land-based missile for the first shot(s) with the potential of saving missiles for 

subsequent shots. The cost advantage of this approach will depend on a number of parameters, as 

shown in Figure RMS-2. Key among these parameters, is the relative cost of high VBO missiles employed 

in a S-A-S firing doctrine (figure RMS-4) compared to slower missiles, that could cover the same 

defended area, employed in a salvo firing doctrine (figure RMS-3). In Figure RMS-11, we analyzed the 

potential value of using regional missiles against threats to CONUS prior to committing the more 

expensive homeland defense missiles in cases in which the regional missiles failed to kill their targets. 

The savings result from a comparison of the “Shoot Regional – Assess – Shoot Homeland Defense” firing 

doctrine to a salvo engagement with homeland defense missiles alone. As seen in Figure RMS-11, the 

savings are a function of the PSSK of the regional missile and the cost ratio of the homeland defense to the 

regional missile. 

In order to develop estimates of absolute savings (versus the relative cost savings in figures RMS-2 and 

RMS-11), we need to convert differences in numbers of missiles fired into dollars saved (or costs 

avoided). This is difficult for two reasons, especially in the context of later phases of the EPAA. First, 

significantly higher VBO missiles are in the initial stages of competitive development, and only very rough 

cost estimates for them are available. Second, missiles such as the GBI 3.0 were developed in the 

context of an integrated Ground-based Mid-course BMD system, and it has been difficult to estimate the 

cost of individual interceptors, which comprise one part of the system. MDA has, however, provided an 

approximate estimate of $70 million per GBI. 

Using these rough cost estimates in conjunction with estimates for the cost of other interceptors in the 

Standard missile family, we are able to develop estimates of potential cost savings from effective 

employment of S-A-S in the context of EPAA. 

 

6 Some clarification of the two firing doctrines, S-A-S and salvo, that we discuss may be useful. A salvo firing doctrine is one in 

which all of the missiles fired against a target are launched in relatively rapid sequence, normally before the first one reaches the 

target. A S-A-S firing doctrine is one in which a single shot or initial salvo is fired but further shots are not made until the results of 

the initial shot or salvo are assessed – i.e., further shots are launched only if it is determined that the first engagement did not kill the 

target. As indicated, that first engagement could be a single shot or it could be a salvo, depending upon the Pssk of the missile, the 

desired probability of no leakage, etc.
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To structure this cost information, we used the current plans for the four phases of the EPAA. These are 

outlined in table 4.1 below.

Table 4.1 General Description of EPAA7

Phase Time frame Planned (cumulative) capabilities

1 2011

Deploy existing missile defenses to defend against short- and medium-range 

ballistic missiles. Planned BMD assets include the deployment of:

• An existing sensor (the AN/TPY-2 radar)

• BMD-capable Aegis ships (Aegis BMD) and the currently fielded 

Standard Missile-3 interceptor (SM-3 Block IA)

2 2015

Field enhanced capability to defend against short- and medium-range ballistic 

missiles. Planned BMD assets to include:

• One Aegis Ashore – a land-based version of the Aegis BMD weapon 

system – in Romania and the more advanced SM-3 Block IB 

interceptor

3 2018

Field enhanced capability to defend against medium- and intermediate-range 

ballistic missiles. Planned BMD assets to include:

• One additional Aegis Ashore in Poland and the upgraded SM-3 Block 

IIA interceptor

4 2020

Field enhanced capability to defend against potentially longer-range threats, 

including intercontinental ballistic missiles. Planned BMD assets include:

• Further upgraded SM-3 Block IIB interceptors

Table 4.2 displays cost estimates provided by MDA of the standard missile family and GBI 3.0. Only a 

rough cost estimate is available for the SM-3 Block IIB interceptor because it is still in the concept phase.

The estimates show increases in unit interceptor cost as seeker systems and VBO improve. 

 

7 Source: GAO Report 11-220, Ballistic Missile Defense: DoD Needs to Address Planning and Implementation Challenges for Future 

Capabilities in Europe, Jan 2011
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Table 4.2. Cost estimates for selected EPAA interceptors8

Interceptor Unit cost estimate

(BY10 $ millions) Characteristics

SM-3 Block IA 9.6 Engage SRBM and MRBM midcourse.

SM-3 Block IB 9.4 Improved seeker and optics 

compared to IA.

SM-3 Block IIA 15.7 Increased VBO to engage IRBMs. 

Limited capability against ICBMs

SM-3 Block IIB 15 (+/- 5) Increased VBO for improved 

capability against ICBMs

GBI 3.0 70 Land-based, CONUS defense 

against ICBMs

In chapter 1, we noted that employing an effective S-A-S doctrine with a PSSK of 0.85 per missile against a 

raid of 30 missiles, a BMD system would need to fire 1.3 interceptors per threat missile for a 50% 

likelihood of no leakage compared to three on average without S-A-S; or 1.45 missiles compared to four

on average for a 90% likelihood of no leakage. We can use these ratios to estimate absolute savings 

provided we know the unit cost of individual interceptors. For these cases, the potential cost savings per 

intercepted missile would be the difference between the cost of 3 salvo missiles and 1.3 S-A-S missiles

for the 50% no leakage case or 4 salvo missiles and 1.45 S-A-S missiles for the 90% no leakage case.

Using information from table 4.2 for a regional case, where the salvo missile is an SM-3 Block IIA ($15.7 

million per missile) and the S-A-S missile employed is an SM-3 Block IIB (upper end cost is about $20M), 

the potential savings by employing effective S-A-S against a 30-missile raid amount to between $630 

million and $1 billion depending on the desired probability of no leakers.9

For the homeland defense case, in which the salvo-only missile is the GBI (~$70 million per missile) and 

the S-A-S missiles are regional (initial shots at $20M per missile) and homeland defense (later shots at 

$70 million per missile), the savings will reflect this greater disparity between the two types of missiles – 

i.e., homeland defense interceptor is 3.5 times greater than the forward-based regional interceptor. For 

this case, the potential savings against a 10 ICBM-class missile raid against CONUS, for a probability of 

no leakers of 0.8, is between $0.8 and $1.2 billion depending on the Pssk of the SM-3 Block IIB missile 

 It should be further noted that 

these savings represent savings in missiles fired against the 30 missile raid. In actuality, the savings 

would be significantly greater, because, not knowing a priori the area in which the attack would be 

directed, missile stockage at all interceptor locations would have to reflect this potential difference in 

required defense missile expenditure. 

 

8 Cost estimates provided by MDA. For SM-3 Block IA, IB, and IIA estimates reflect buy sizes of 128, 371, and 78, respectively. 

Because of learning curve effects, the relatively higher quantity of Block IIB missiles somewhat lowers the apparent cost of these 

missiles in comparison to the others. A cost estimate range is provided for SM-3 Block IIB, which is still in development.

9 The calculation is straightforward. For a 50% likelihood of no leakers, the cost of successfully engaging a missile employing S-A-S 

would be 1.3 times the cost of an SM-3 Block IIB missile or $26 million. The cost of defeating the same missile employing an SM-3 

Block IIA using salvo fire would be 3 times the cost of the SM-3 Block IIA or $47 million. The implied cost savings employing S-A-S 

is therefore about $21 million per attacking missile or $630 million for a 30-missile raid. A similar approach holds for a 90% 

likelihood of no leakers comparing the cost of 1.45 S-A-S interceptors with 4 salvo interceptors.
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against ICBMs (here we assume the range of 0.4 to 0.7 as in figure RMS 11). If the PSSK for this missile 

is higher, e.g., 0.8, and the objective of no leakers is a more aggressive 0.95 probability, the potential 

savings are significantly greater, in the order of $2 billion. As in the regional defense case, all of these 

potential savings would have to be multiplied up by a factor of two or three, to account for the number of 

widely separated regional missile firing locations, i.e., those that are required to protect different areas of 

CONUS against attack to ensure that the necessary numbers of first shot regional missiles are available 

for firing, regardless of where the attack is directed. 

Thus, although the specific details of defense objectives, regional missile Pssk, and relative costs 

between the homeland defense and regional missiles are somewhat uncertain at this point in time, this 

analysis indicates that there are substantial opportunities for savings in defense of CONUS through 

employing an early intercept against ICBMs from EPAA forward based regional missiles enabling a S-A-S 

firing doctrine in conjunction with more costly rearward based homeland defense missiles. 
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Chapter 5: 

Findings and Recommendations

Findings

EI in and of itself is not a useful objective for missile defense in general or for any particular missile 

defense system. Intercept prior to the potential deployment of multiple warheads or penetration aids – 

the principal reason often cited for EI – requires Herculean effort and is not realistically achievable, even 

under the most optimistic set of deployment, sensor capability, and missile technology assumptions.

Nor does EI itself provide the capability to defend a large area. Rather, it is the forward basing of 

interceptor assets and high interceptor speeds that facilitate large defended areas. In fact, requiring even 

a modestly EI, e.g., before apogee, can often take away much of the benefit that forward deployment of 

interceptors can provide. 

EI can facilitate a S-A-S firing doctrine, which, if successful, has the potential to make the defense much 

more cost-effective. But it is not EI itself that makes this possible; rather it is large battlespace, however 

obtained, that enables it. Key contributors to battlespace are forward-based, long-range sensors; 

properly placed interceptors; interceptor velocity; and low-latency command and control, battle 

management, and communications, with robust networking of sensor-to-sensor and sensor-to–shooter 

communications. The other necessary component of S-A-S is very-high-quality kill assessment, without 

which there can be no effective S-A-S. The Task Force saw no analysis that indicated whether or not 

such very low error rates are achievable. We believe that such analyses, if not already available, need to 

be performed, given the potential of S-A-S to achieve large savings in missile inventory and cost.

We found that, kinematically, S-A-S is feasible for regional defenses within the currently planned 

capabilities of interceptor velocities and advanced sensors. A different application of “EI,” namely the use

of forward-deployed regional missile defense assets to contribute to the homeland defense of the U.S. 

against rogue states, appeared to have large potential benefit. The geometry of European regional 

defense and potential adversaries in the Mid-East are such that if any intercept by regional defense 

assets of an ICBM targeted against the U.S. homeland from a regional adversary were possible, that 

intercept would occur before rearward-based GBIs had to be fired. Given the anticipated large cost 

difference between GBIs and regional defense interceptors, this would enable a firing doctrine of: (1) 

shoot a salvo of regionally based interceptors, (2) assess the result, and (3) shoot GBIs only at the 

surviving warheads. However, the Task Force also found that this forward-based intercept of ICBMs from 

regional defense deployments would require a significant increase of velocity beyond that currently 

planned for advanced regional interceptors. There could be some reduction in this additional requirement 

if advanced missiles could be deployed both on land and at sea. More optimistic assumptions on 

launching soon after or even before enemy missile burnout do not have a significant impact on required 

missile velocity.

Other indispensible characteristics of an effective missile defense system are the ability to dependably 

discriminate reentry vehicles from penetration aids and other objects, and interceptors with high singleshot kill probability. These both are fundamental attributes of cost-effective missile defense. 

In summary, pursuit of the current plans for regional ballistic missile defense, such as envisioned in the 

PAA, if pursued to completion, will provide an effective regional defense capability – those plans are 
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technically feasible, are making good progress, and enjoy broad political support. The fact that the Task 

Force does not believe EI, as defined in its TOR, is either a realistic or useful missile defense objective 

does not detract from the beneficial position that regional missile defense now occupies. We endorse 

current efforts within MDA to bring this to fruition.

Recommendations

The Task Force finds that the Missile Defense Agency is on a path to achieve effective regional defense. 

We recommend that MDA:

• Reduce the emphasis on EI per se.

• Increase the emphasis on system and element advances that contribute to expanded 

battlespace, larger defended area, and improved single-shot kill probability. These objectives are 

fundamental, are easily measureable, and have high payoff.

• Increase emphasis on research and development to:

o Understand the fundamental contributors to non-kills, understand the ability and timing for 

assessing non-kills, and improve kill assessment methods and techniques, key to a 

useful S-A-S firing doctrine;

o Provide robust networked operations of sensors, shooters, and command and control, 

ensuring robust connectivity, high quality of service, and low latency. Ensure that 

potential adversary techniques to deny such capabilities can be defeated or mitigated, 

should the need arise; and

o Improve capabilities for the exo-atmospheric discrimination of warheads from penetration 

aids, debris, and other objects. Ensure that the use of all observables from the ensemble 

of sensors available to missile defense are used to the extent possible.

• Develop future plans and capabilities, both within MDA and in coordination with current service 

efforts, for:

o Growth of shipboard and land-based RF sensors beyond the currently planned 

capabilities;

o More advanced technology for regional missiles with the proper balance between higher 

velocity, lateral movement capability, payload weight and shorter burn time and with the 

potential to be deployed both on land and at sea.

• Continue the development of an airborne infrared sensor, and conduct systems analyses to better 

understand its potential benefits and limitations as part of the BMD architecture.

• Continue development of space based infrared sensors as part of the BMD architecture for both 

regional and homeland missions. 
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Appendix A: Terms of Reference 
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Appendix B: Task Force Membership

CO-CHAIRMEN

ADM WILLIAM J. FALLON, USN (RET) NEURALIQ

GEN LESTER L. LYLES, USAF (RET) PRIVATE CONSULTANT

EXECUTIVE SECRETARIAT

COL STANLEY STAFIRA, JR., USAF MISSILE DEFENSE AGENCY

MEMBERS

DR. WANDA AUSTIN AEROSPACE CORPORATION

GEN PAUL KERN, USA (RET) PRIVATE CONSULTANT

DR. WILLIAM LAPLANTE MITRE CORPORATION

DR. MARK LEWELLYN JOHN HOPKINS UNIVERSITY APPLIED PHYSICS 

LABORATORY

VADM RODNEY REMPT, USN (RET) PRIVATE CONSULTANT

DR. GEORGE SCHNEITER PRIVATE CONSULTANT

MR. ROBERT STEIN PRIVATE CONSULTANT

RADM BRAD HICKS, USN (RET) PRIVATE CONSULTANT

BRIG GEN MARK OWEN, USA(RET) NORTHROP GRUMMAN CORPORATION

SENIOR REVIEWER

MR. WILLIAM DELANEY MIT LINCOLN LABORATORY

GOVERNMENT ADVISOR

DR. SPIRO LEKOUDIS OSD, AT&L

DEFENSE SCIENCE BOARD

Mr. Brian Hughes DEFENSE SCIENCE BOARD

LTC Karen Walters, USA DEFENSE SCIENCE BOARD

CDR Doug Reinbold, USN DEFENSE SCIENCE BOARD

SUPPORT

MR. CHRIS GRISAFE SAIC

MS. TAMMY-JEAN BEATTY SAIC
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Appendix C: List of Briefings

ABIR MDA

ADVANCE LASER RESEARCH PROGRAM MDA

ADVANCED DIRECTED ENERGY TECHNOLOGY LAWRENCE LIVERMORE NATIONAL LABORATORY

AEGIS AND AEGIS ASHORE MDA

AEROSPACE CORPORATION AEROSPACE CORPORATION

AIR LAUNCH HIT-TO-KILL MDA

APPLIED PHYSICS LABORATORY JOHNS HOPKINS/APL

ARCHITECTURAL NEEDS AND POTENTIAL 

AIRBORNE LASER SYSTEM CONCEPTS MDA

ARROW WEAPON SYSTEM MDA

BMDS ARCHITECTURE MDA

C2BMC AND EARLY INTERCEPT MDA

COUNTERMEASURES LINCOLN LAB

DIRECTED ENERGY: ALTB MDA

EARLY INTERCEPT OVERVIEW MDA

GROUND SENSORS MDA

HIGH FRAME RATE IR STARING SENSOR SYSTEMS USAF

JOINT INTEGRATED AIR AND MISSILE DEFENSE 

ORGANIZATION

JOINT INTEGRATED AIR AND MISSILE DEFENSE 

ORGANIZATION

LB SM-3 STUDY MDA

LOCKHEED MARTIN COMPANY LOCKHEED MARTIN COMPANY

NORTHROP GRUMMAN NORTHROP GRUMMAN

POLICY BRIEFING OSD-POLICY

RAYTHEON RAYTHEON

SANDIA NATIONAL LABORATORY SANDIA NATIONAL LABORATORY

SM-3 BLOCK IIB MDA

SPACE ARCHITECTURE MDA

THE BOEING COMPANY THE BOEING COMPANY

THREAT BRIEF MSIC/NASIC

UHF RADAR LINCOLN LAB
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Appendix D: Briefers 

MS. KARI ANDERSON MR. SCOTT PERRY 

MR. BILL DELANEY MR. STEVE POST 

MR. NEIL DOAR MR. RICHARD RITTER 

COL LAURENCE DOBROT DR. BRAD ROBERTS

MR. ERIC FORREST MR. KEVIN ROBINSON

MS. ALISON FORTIER DR. WILL ROPER 

MR. CONRAD GRANT DR. WILL ROPER

DR. GREG HYSLOP MR. JOHN ROWE

MR. MICHAEL JACOBS MS. LAUREE SHAMPINE

MR. LARRY JONES MR. KIRK SHAWHAN

MR. MICHAEL KELLY MR. BENNY SHEEKS

MR. JOHN KIRK DR. CRAIG SIDERS

DR. MARK LEWELLYN MR. BOB STEIN

RADM ARCHER MACY MR. EDWARD TAYLOR 

MR. RICHARD MATLOCK MR. STAN THOMAS

CAPT DENNIS MURPHY MR. GABE WATSON

MR. KEVIN O’BRIEN DR. LOU WEINER

DR. DANIEL O’CONNOR MS. LORA WIRTH 

MR. JOHN O’PRAY MR. KEVIN ZONDERVAN
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Appendix E: Acronyms

ABIR AIRBORNE INFRARED PROGRAM

AMDR AIR AND MISSILE DEFENSE RADAR

AN/TPY-2 ARMY-NAVY TRANSPORTABLE RADAR SURVEILLANCE

BMD BALLISTIC MISSILE DEFENSE 

BMDR BALLISTIC MISSILE DEFENSE REVIEW

BMDS BALLISTIC MISSILE DEFENSE SYSTEM

BOA BMDS OVERHEAD ARCHITECTURE

CONUS CONTINENTAL UNITED STATES

C2BMC COMMAND, CONTROL, BATTLE MANAGEMENT & COMMUNICATIONS

EI EARLY INTERCEPT

EPAA EUROPEAN PHASED ADAPTIVE APPROACH

GBI GROUND-BASED INTERCEPTOR

ICBM INTERCONTINENTAL BALLISTIC MISSILE

IR INFRARED

JOG JOINT OPIR GROUND

MDA MISSILE DEFENSE AGENCY

MRBM MEDIUM RANGE BALLISTIC MISSILE

PAA PHASED ADAPTIVE APPROACH

PSSK SINGLE-SHOT KILL PROBABILITY

PTSS PRECISION TRACKING SPACE SYSTEM

RF RADIO FREQUENCY

RV REENTRY VEHICLE

S-A-S SHOOT-ASSESS-SHOOT

SM STANDARD MISSILE

SRBM SHORT RANGE BALLISTIC MISSILE
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Defense Science Board

The Pentagon

OUSD (AT&L) Room 3B888A

Washington, DC 20310

(703) 695-4157