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5
Recommended Path Forward
ORGANIZATION
As previously noted, this chapter provides additional details on the recom-
mended evolution for the Ground-Based Midcourse Defense (GMD) system (i.e.,
the recommended evolution to GMD, called GMD-E in this chapter), as called for
by Major Recommendation 5 in the Summary and Chapter 4 of this report, “as
a means to provide adequate coverage for defense of the U.S. homeland against
likely developments in North Korea and Iran over the next decade or two at an
affordable and efficient 20-yr life cycle cost, the Missile Defense Agency should
implement an evolutionary approach to the GMD system as recommended in
this report.”
Before introducing the details of the GMD-E, the basis for Major Recom-
mendation 5 and the key concepts of operations (CONOPS) for providing an
effective defense of the United States and Canada at lowest cost are discussed.
BASIS FOR MAJOR RECOMMENDATION 5
As part of its congressional tasking, the committee assessed the practicality
of boost-phase defense in comparison to other alternatives, taking into account
realistic CONOPS, force structure, effectiveness, life-cycle cost (LCC), and
resilience to countermeasures, among other things. In doing so, the committee’s
analysis led to the following conclusion: The 30 current ground-based intercep-
tors (GBIs), as part of the GMD system deployed at Fort Greely, Alaska (FGA),
and Vandenberg Air Force Base, California (VAFB), evolved to their current
configuration through a series of decisions and constraints. They provide an
early, but fragile, U.S. homeland defense capability in response primarily to a
130
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RECOMMENDED PATH FORWARD 131
potential North Korean threat. Moreover, the current GBIs are very expensive per
round when compared to missiles of similar complexity at the same point in their
development and has limited ability to defend the eastern United States against
threats from the Middle East.
Consequently, the committee believes that a properly designed midcourse
defense is the most versatile and cost-effective way to provide a resilient limited
defense of the United States. Specifically, the committee finds as follows:
1. The GMD system lacks fundamental features long known to maximize
the effectiveness of a midcourse hit-to-kill defense capability against even limited
threats. They could, however, readily be incorporated as part of the recommended
GMD-E described in this chapter. The cost-effectiveness of various alternatives
shown in Chapter 4 suggests that a substantially lower overall cost could be
achieved through an evolution that is detailed in this chapter.
2. Discriminating between actual warheads and lightweight countermea-
sures has been a contentious issue for midcourse defense for more than 40 years
(see classified Appendix J for greater detail). Based on the information presented
to it by the Missile Defense Agency (MDA), the committee learned very little
that would help resolve the discrimination issue in the presence of sophisticated
countermeasures. In fact, the committee had to seek out people who had put
together experiments like the midcourse space experiment (MSX) and High-
Altitude Observatory 2 (HALO-2) and who had understood and analyzed the
data gathered. Their funding was terminated several years ago, ostensibly for
budget reasons, and their expertise was lost. When the committee asked MDA
to provide real signature data from all flight tests, MDA did not appear to know
where to find them. MDA showed the committee summaries of results without
the data to support them. It appeared to the committee that MDA has given up
trying and has terminated most of the optical signature analysis of flight data
taken over the past 40 years. In the committee’s view, this is a serious mistake.
3. It is clear that advances in technology for both long-wave infrared sen-
sors and X-band radars that can coherently integrate and do Doppler imaging are
impressive and offer new opportunities. The fundamental concept for maximizing
the effectiveness is presented below (see classified Appendix J for greater detail).
4. In addition to its long-term cost and performance advantages, the recom-
mended GMD evolution as provided in the following sections of this chapter, if
adopted, would decouple the defense of North America from decisions and issues
related to the configuration of NATO missile defense, even avoiding altogether
the need for PAA.
In short, the recommended GMD-E involves a smaller, shorter burn intercep-
tor configuration that builds on development work already done by MDA under
the Kinetic Energy Intercept (KEI) program, but with a different front end. The
heavier, more capable kill vehicle (KV) with a larger onboard sensor provides
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132 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
the capabilities absent in the current GMD system but responsive to the recom-
mended CONOPS, which will be discussed. The GBIs would first be deployed
at a new third site in the northeast United States along with five additional
X-band radars using doubled Terminal High-Altitude Area Defense (THAAD)
Army Navy/transportable radar surveillance (AN/TPY-2) capabilities integrated
together at each upgraded early warning radar (UEWR) site and at Grand Forks,
North Dakota. At a later time, the more capable interceptor would be retrofitted
into the silos at Fort Greely, Alaska, with the existing GBIs diverted to the targets
program supporting future operational flight tests.
Much of the basis for the recommended GMD-E has been provided in
Chapters 3 and 4. The committee believes that the recommended GMD-E offers
a much more resilient although limited U.S. homeland defense against any threat
at the lowest 20-yr life cycle cost, and that it can be accomplished within the same
requested cumulative 5-yr total obligation authority (TOA) through FY 2016 as
in the current plan. Before providing additional information on the recommended
GMD-E, it is important to consider the key CONOPS for providing an effective
defense of the United States and Canada.
KEY CONOPS FOR EFFECTIVE DEFENSE OF
THE UNITED STATES AND CANADA
Defending high-value assets against attack from ballistic missiles requires
minimizing the possibility of leakage through the defense for any reason while
also minimizing the wasting of interceptors. The contributors to leakage and
wastage are discussed in classified Appendix J. In general, these requirements
demand, to the maximum extent possible, a level of robustness that can overcome
or at least minimize the effects of uncertainties in threat knowledge, the failure
of hardware to function as anticipated, or surprises in the adversary’s tactics or
capabilities.
Realistic Approach to Maximizing Midcourse Discrimination Effectiveness
While good intelligence provides knowledge of the adversary’s capabilities,
it is rarely perfect, and surprises are to be expected and accommodated. The com-
mittee believes that the key to maximizing the ability to discriminate lethal war-
heads in the presence of countermeasures is exploiting the concurrent intermittent
viewing by X-band radar and interceptor optics for an extended (>100 sec) time
as the interceptor closes on the target complex. Yet this has been ignored in the
current GMD system architecture.
The reason for this seems to be a reluctance to commit an interceptor before
having high confidence about the threat complex from some source. Yet, in an
attempt to avoid the midcourse discrimination issue, proponents of boost-phase
(or early) intercept are willing to commit interceptors before even knowing where
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RECOMMENDED PATH FORWARD 133
the threat is going. Surely, then, we should be willing to commit interceptors after
the threat has burned out and its throw weight impact point has been determined
by both space-based infrared system (SBIRS) and forward radars so we know
where to look for the threat and where the threat is going.
An interceptor launched with only that knowledge, its own observation abil-
ity, and enough maneuver ability to cover the remaining uncertainty along with a
forward ground-based X-band radar (GBX) observation provides the most valu-
able threat discrimination tool as the interceptor closes on the threat, hunting for
the right target. Has it been wasted? Not unless the adversary expends missiles
with no payloads on them. May more interceptors be required? Perhaps, depend-
ing on what is observed by the first one, which serves as a scout and together with
radar observations provides more data than any other source. But this requires
getting time on the side of the defense. It requires maximizing and making ef-
ficient use of the battle space, i.e., it calls for shoot-look-shoot (SLS).
Figure 5-1 illustrates how the synergy of concurrent observations can be
exploited. The high-resolution X-band radar enables Doppler imaging to measure
SBIRS OPIR TWAA
THREAT • TW trajectory est.
ELEMENTS • Raid size 1
• Typing by location
Boosters and plume signature (t) INTERCEPTOR
X-BAND RADAR
2 • Load and update
Threat • Cued search w/ Search Cue
object state vectors
Complex coherent pulse and Tasking BATTLE MGR • Fly-out toward
integration. 3
assigned threat
• Early acquisition • Attack assess Prelaunch
and track of the • Select threat
complex 6
and Update
threat complex complex to 5 via Radar KILL VEHICLE IR
engage and plan SENSOR/COMPUTER
• Object track files intercept • Acquire and track
state vectors and • Intercept complex and objects
initial TOM assignments in assigned view area
• Doppler imaging • Assess results • Create object files
Threat of threat objects and follow-up
Compare • TOM correlated
Objects 4 shots 11 Radar and 9 with radar metrics
• Dynamics, size, and • Override option Optical Metrics • Send IR scene (t)
scattering centers
• Apply optical 8
• Credibility ranking
discriminants (t)
7 • Dynamics, size, and
• Communicate with
in-band intensity (t)
interceptors
• Credibility ranking
• Kill assessment
Communication Links via Radars
Communication Links via Radars
12 • Designate target 10
FIGURE 5-1 Synergy of concurrent radar and KV optical observations. OPIR, other pro-
-
gram infrared; TWAA, tactical warning and attack assessment; IR, infrared.
FIGURE 5-1
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134 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
the dynamic behavior of each object in the threat and to see unique signatures
from scattering centers as the objects spin, tumble, and nutate in response to
disturbances due to deployment methods. It also provides accurate metrics on
the position and state vector of each object in the complex and provides all that
information through the battle manager to the interceptor to correlate with its op-
tical measurements. The interceptor optics also measure the time-varying thermal
signature, which provides information about thermal mass, object dynamics, and
the movement of objects in the threat; this information is transmitted back to the
battle management command, control, and communications (BMC3) for contin-
ued use. Together, these observations make countermeasures more difficult over
the total viewing and engagement time. Moreover, countermeasures that may be
effective against the first interceptor will in many cases have outlived their ef-
fectiveness against subsequent interceptors.
Exoatmospheric discrimination by definition requires identifying the threat-
ening reentry vehicle (RV) from among the cluster of other nonthreatening
objects that will be visible to the defense’s sensors after the end of powered
flight. Initially the nonthreatening objects may be “unintentional”—for example,
spent upper stages, deployment or attitude-control modules, separation debris,
debris from unburned fuel, insulation, and other components from the booster.
However, as threat sophistication increases, the defense is likely to have to deal
with purposeful countermeasures—decoys and other penetration aids and tactics
to include salvo launches and antisimulation devices—that adversaries will have
deliberately designed to frustrate U.S. defenses.
Evaluating discrimination effectiveness is an uncertain business. One should
avoid overstating the ease with which countermeasures that are theoretically
possible can actually be made to work in practice, especially against advanced
discrimination techniques using multiple phenomenologies from multiple sensors
and exploiting the long observation time that midcourse intercept makes possible.
It is perhaps noteworthy that U.S. (and U.K.) experience with the development
of high-confidence penetration aids during the Cold War was of mixed success.
It would be difficult for an adversary to have confidence in countermeasures
without extensive testing, which the United States might be able to observe and
gather data on that would permit defeating the countermeasures.
The art of midcourse discrimination, developed over many decades, does not
provide perfect selection of RVs, but the committee believes that by designing a
ballistic missile defense (BMD) architecture based on the capabilities described
below, an adequate level of discrimination performance can be achieved in the
near term, and that this approach has a reasonable chance of keeping the United
States generally ahead in the contest between countermeasures and counter-
countermeasures. This having been said, the reader should understand that there
is no static answer to the question of whether a missile defense can work against
countermeasures. It depends on the resources expended by the offense and the
defense and the knowledge each has of the other’s systems.
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RECOMMENDED PATH FORWARD 135
While the current GMD may be effective against the near-term threat from
North Korea, the committee disagrees with the statement in the BMDR report
concluding that this capability can be maintained “for the foreseeable future.” 1
The committee understands this to mean the next decade or so. If the threat is to
be countered for the foreseeable future, the United States needs to take the steps
outlined below to maintain discrimination capability.
The BMD system capabilities that provide reasonable discrimination pros-
pects are mostly supported by the available hardware and techniques, but they
have yet to be included in the existing or planned GMD architecture. The system
capabilities include the following:
1. The threat complex must be observed at frequent intervals by instru-
ments capable of obtaining discrimination data from the time of booster burnout
until intercept occurs (see Figure 5-1).
2. Observation of the threat is possible and necessary in both microwave
and optical bands, and the resulting data must be fused into a target object map
(TOM) to be used by the interceptors.
3. While other observations can be useful, it is the high-resolution data
from X-band radar and IR seekers such as those on the KV that contribute most
of the discrimination capability. Those instruments must be located, tasked, and
equipped to provide these data as soon as practical after booster burnout on-
ward, with minimal distractions for housekeeping and other duties. Investment
in low- esolution measurements should have lower priority than investments in
r
high-resolution measurements.
4. The ability to form and interpret TOMs over a time that is typically
many hundreds of seconds for midcourse intercept increases the likelihood of
successful discrimination. The TOMs must therefore be exchanged frequently
with the interceptor KVs during fly-out.
5. Data from the KV’s onboard seeker can be used to improve the dis-
crimination effectiveness of subsequent intercept attempts and should therefore
be downlinked from the interceptor during flight.
6. To take full advantage of combined radar and KV observations, the
BMD system architectures and firing doctrine should enforce and exploit the
maximum battle space for SLS capabilities.
More generally, the committee believes that a long-term approach to mid-
course countermeasures involves the following:
1. Recognizing that discrimination is not separate from the overall BMD
system architecture and that synergies should be exploited where possible, spe-
cifically through layered defenses such as postboost intercept and SLS tactics.
1
Department of Defense. 2010. Ballistic Missile Defense Review Report, Washington, D.C., Febru-
ary, pp. 9, 15, and 47.
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136 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
2. Understanding that the countermeasure threat is not constant and that
there is no permanent solution. A continuing program of test and analysis is nec-
essary to maintain the technical capacity that will support an adequate level of
discrimination as new countermeasures are developed and deployed.
3. Implementing a more realistic and robust program to gather data from
flight tests and experiments (including on flights of U.S. missiles) from the full
range of sensors and making full use of the extensive data collected from past
experiments to continue developing the applied science from which robust dis-
crimination techniques and algorithms can be developed.
4. Maintaining an active R&D program on discrimination techniques.
Radar Discrimination
Opponents of BMD systems correctly point out that the system is defective
if it lacks the ability to select threatening targets among the many objects that
accompany them. This ability can be enhanced by observation over the longest
possible time by X-band radars. Classified Appendix J discusses issues of radar
discrimination, with the conclusion that an adequate solution of the problem is
possible. A generalized summary of those considerations is as follows.
• Bandwidth. X-band radars are used in defense systems to perform preci-
sion tracking and target classification functions. The choice of this band by both
U.S. and foreign radar engineers is based partly on the broad system bandwidth
inherent in X-band operation, which allows transmission of wideband waveforms
that resolve and measure individual objects without interference from others in
a target cluster. Wideband waveforms permit direct measurement of the radial
extent of each object (called range profiling, a standard approach to radar target
classification in air and missile warfare). The radial extent of objects that change
their aspect angle by a significant amount over the observation time—for ex-
ample, rotating objects or stable objects viewed from a position outside the plane
of the trajectory—provides measurement in two dimensions.
• Cross-section. For objects that are resolvable with wideband waveforms,
tracking radars can collect and measure the radar cross-section (RCS) of each
object within the target cluster. The absolute RCS is sensitive to details of the
object’s size, shape, surface roughness, and material.
• Range Doppler Imaging. Wide-bandwidth echoes from an object, col-
lected over an extended train of coherent pulses, can be processed to provide a
two-dimensional image of the object, as illustrated in Figure 5-2.2 Such images
can be collected simultaneously on objects in a target cluster while they remain
within the beamwidth of the radar. Some fraction of the objects can be expected
2
JosephM. Usoff, MIT Lincoln Laboratory. 2007. “Haystack Ultra-wideband Satellite Imaging
Radar (HUSIR),” 2007 IEEE Radar Conf., Boston, Mass., April 17-20, Plenary Session, pp. 17-22,
©IEEE.
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RECOMMENDED PATH FORWARD 137
FIGURE 5-2 Example of ISAR satellite imaging from the Haystack radar complex.
to rotate at rates that permit rapid classification of small or irregular nonthreaten-
ing debris. Decoys too small to present a threat can also be discriminated over
periods of several seconds. The coherent process used in imaging also improves
the sensitivity of a radar so that objects with cross-sections smaller than required
for acquisition of the track can be located and their relative positions measured.
• Position measurement. With adequate signal-to-noise ratio, a monopulse
tracking radar can limit measurement error to less than 1 percent of its beam-
width. Over extended track periods, the relative positions can be refined by a
further order of magnitude. Along with measurement of relative range to within
fractions of a meter, using wideband waveforms, these position data provide a
three-dimensional target object map that can be converted to the angular coordi-
nates of a homing seeker, ensuring proper registration of each object in the target
cluster.
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138 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
• Precession and nutation. The range-Doppler image of each object is
sensitive to small angular motions of the object, representing precession and
nutation of its axes.3 Observation of these parameters over an extended period
provides additional discriminants that are not available by other means.
• Object mass. Objects having insufficient mass to constitute threats can
be excluded as targets for defensive action. To the extent that forward-based
X-band radar siting permits viewing the threat before booster burnout, tracking
of the booster through burnout and deployment of the RV can be useful in this
regard.
• Capabilities of other radars. It has been suggested that the Aegis AN/
SPY-1 and the upgraded UHF early warning radars can provide discrimination,
or at least classification, of target objects. These radars have only limited range
resolution capability, far below that of the X-band radars.
The signal bandwidth of the UHF radars is limited to a few megahertz, both
by equipment design and by ionospheric propagation effects. The resulting range
resolution is measured in tens of meters. The beamwidths of the UHF radars are
approximately 2 degrees. The lack of resolution increases the probability that two
or more objects will lie in the same resolution cell, precluding accurate measure-
ments of any sort on the individual objects that would be useful for discrimina-
tion or classification. Widely spaced targets might permit classification, but the
contribution to discrimination and target selection is negligible.
In summary, it is concluded that observation over the longest possible time
by X-band radars is a prerequisite for midcourse discrimination. These radars
were designed to perform this function, and it is essential that they be assigned
to perform tracking and discrimination functions using all their resources, leaving
search and warning to the low-resolution radar systems and overhead sensors that
were designed for that purpose. The failure to exploit fully the ability to extend
the synergy between the two sensor classes, which permits extending the range
of the X-band radar tracking and discrimination, has unnecessarily compromised
the performance of the present BMD system.
Finally, although much of the early work on decoy discrimination involved
optical techniques, it appears that with the advent of very capable X-band ra-
dars, MDA has shifted away from this approach over the past decade. While
the committee largely agrees with this shift in emphasis, work on sensors and
optical discrimination should be continued because optical techniques have not
been exploited to their fullest as the committee recommends. Classified Ap-
pendix J provides additional discussion and analysis related to classical optical
discrimination.
3
V.V.Chen and H. Ling, Naval Research Laboratory. 2002. Time-Frequency Transforms for Radar
Imaging and Signal Analysis, Artech House, Norwood, Mass.
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RECOMMENDED PATH FORWARD 139
Fundamental Precepts of a Cost-Effective Ballistic Missile Defense
The following principles should be respected:
1. Understand the threat variables and the adversary’s objectives and de-
sign to deny them;
2. Provide margin and options for unanticipated events or behavior;
3. Make time an ally not an enemy;
4. Keep it as simple as possible;
5. Delegate responsibility for real-time decisions to the proper level rather
than centralize them; and
6. Make the best use of the nature of the assets available and minimize the
need for new ones.
The committee finds the current GMD system deficient with respect to all of
these principles.
Functional Delegation
Table 5-1 displays the functions that must be performed in defending against
a ballistic missile attack independent of where it is launched from or where it is
going. It indicates what sensors are needed and what they do and do not provide
in the way of information that the defense can use. In effect, the information in
the table helps define the CONOPS and the architecture. The following discus-
sion amplifies Table 5-1 vis-à-vis the four missile defense missions discussed
throughout this report.
Threat Characterization
The characteristics of threats in the scenarios delineated by the congressional
task are discussed generally in Chapter 1 and in detail in classified Appendix F.
In addition, Chapter 2 presented the challenges of the timelines for boost-phase
defense. Here, some timelines are recapped as the committee considers CONOPS
for the various missions.
• An intercontinental ballistic missile (ICBM) launched from central Iran
to the U.S. East Coast would have a maximum range total flight time of about 40
minutes. If it were liquid propelled, the boosted portion of that flight time would
last about 250 sec, and if solid propelled, it would last about 180 sec. Similar
flight durations would apply to threats from North Korea. At least some if not
all solid-propelled missiles and all liquid-propelled missiles would have thrust
termination capability and could also use excess energy to loft or depress their
trajectory at less than maximum range.
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140 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
TABLE 5-1 Recommended Missile Defense CONOPS and Function Delegation
Phase of Command
Threat Function Level Intelligence Surveillance Sensors
Peacetime Surveillance Approve Monitor Broad area surveillance
doctrine developments and
and ROE assess capabilities,
for lower order of battle,
levels and intentions
Heightened Alert Increase Estimate Respond to DEFCON
tensions DEFCON intentions status with focus on
level and tactics of adversary AOR
adversary
Threat TWAA Delegate Determine Determine raid size,
launch and defense adversary’s throw weight, impact
powered authority to remaining assets, prediction, missile typing.
flight appropriate locations, and Cue defense acquisition
COCOM capabilities and tracking sensors
Threat Defense acquisition, Monitor Support NCA/ Maintain surveillance for
midcourse tracking, and COCOM response follow-on attacks from
flight engagement planning and contingency same or other sources
planning
Engage and plan 2nd Monitor
shot
Target designation Implement
contingency
plan
Postdesignation Response
assessment plan
Intercept Monitor
Reentry Follow-on Monitor
engagements
Terminal engagement
within atmosphere
NOTE: AOR, area of responsibility; ROE, rules of engagement; NCA, National Command Authority;
COCOM, combatant commander; TWAA, tactical warning and attack assessment; DEFCON, Defense
Readiness Condition.
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164 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
TABLE 5-3 Typical Mission Timeline
Mission
Timeline
(sec) Mission Event Sequence
0 Threat launch
30 Initial DSP report
125 Begin track Azerbaijan XBR (R = 872 km; elev = 2.2 deg)
180 Threat booster burnout
190 First shot interceptor launched from Poland site (commit on track from Azerbaijan
XBR)
260 Interceptor burnout
339 KV sensor acquires threat complex (R2Tgt = 1,994 km; T2Go = 177 sec; R2Int =
1,061 km)
349 Initial course correction divert (R2Tgt = 1,883 km; T2Go = 167 sec; R2Int = 999 km)
516 First shot intercept opportunity (Alt = 836 km; R = 1,462 km; ITOF = 326 sec; closing
vel 11.3 km/sec; Xang = 36 deg)
Second shot (SLS) interceptor launched from Poland site (commit on Fylingdales GBX
track + TOM from previous KV sensor)
Interceptor burnout
KV sensor acquires threat complex (R2Tgt = 1,000 km; T2Go = 116 sec; R2Int =
692 km)
Initial optional course correction divert (R2Tgt = 915 km; T2Go = 106 sec; R2Int =
636 km)
Second shot intercept opportunity (Alt = 1,111 km; FO R = 302 km; ITOF = 196 sec;
closing vel = 8.6 km/sec; Xang = deg)
Kill (hit) assessment by Fylingdales GBX (R = 2,780 km; elev = 6.3 deg)
526 Second shot (SLS) interceptor launched from Poland site (commit on Fylingdales GBX
track + TOM from previous KV sensor)
616 Interceptor burnout
626 KV sensor acquires threat complex (R2Tgt = 1,000 km; T2Go = 116 sec; R2Int =
692 km)
636 Initial optional course correction divert (R2Tgt = 915 km; T2Go = 106 sec; R2Int =
636 km)
742 Second shot intercept opportunity (Alt = 1,111 km; FO R = 302 km; ITOF = 196 sec;
closing vel = 8.6 km/sec; Xang = deg)
752 Kill (hit) assessment by Fylingdales GBX (R = 2,780 km; elev = 6.3 deg)
772 Third shot (SLS) interceptor launched from Caribou (commit on Fylingdales GBX track
+ TOM from previous KV sensor)
842 Interceptor burnout
1,081 Threat reaches its trajectory apogee
1,201 KV sensor acquires threat complex (R2Tgt = 1,992 km; T2Go = 180 sec; R2Int =
985 km)
1,211 Initial optional course correction divert (R2Tgt = 882 km; T2Go = 170 sec; R2Int =
929 km)
1,381 Third shot intercept opportunity (Alt = 1,144 km; R = 2,770 km; ITOF = 609 sec;
closing vel = 11.1 km/sec; Xang = 8.4 deg)
1,391 Kill (hit) assessment by Fylingdales (R = 2,382 km; elev = nm19/4 deg)
1,411 Fourth shot (SLS) interceptor launched from Caribou (commit on Fylingdales GBX
track + TOM from previous KV sensor)
1,481 Intercept burnout
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RECOMMENDED PATH FORWARD 165
TABLE 5-3 Continued
1,515 KV sensor acquires threat complex (R2Tgt = 1,998 km; T2Go = 167 sec; R2Int =
1,031 km)
1,525 Initial optional course correct divert (R2Tgt = 1,879; T2Go = 157 sec; R2Int = 967 km)
1,682 Fourth shot intercept opportunity (Alt = 780 km; FO R = 1,174 km; ITOF = 271 sec;
closing vel = 12 km/sec; Xang = 16 deg)
1,692 Kill (hit) assessment by Cape Cod GBX (R = 1,870 km; elev = 16.6 deg)
Battle space remaining = 319 sec
2,021 Threat reaches minimum intercept altitude if not intercepted
2,050 Threat reaches target if not intercepted
NOTE: Hypothetical Middle East to East Coast CONUS four-shot SLS scenario. R, range; FO,
fly-out.
This analysis represents a reasonably thorough conceptual analysis of hypo-
thetical threats and is by no means optimized to achieve a good balance among
the sensor and interceptor elements. Such a balance would require a much more
rigorous and broader-ranging assessment of parametric technical requirements
and an evaluation of system design. However, the committee believes the analysis
presented below can point the way to a layered missile defense concept that will
be very effective and highly responsive to the changing strategic environment and
to the uncertainties surrounding who our adversary might one day be.
Middle East Threat to CONUS East Coast
Figures 5-16 and 5-17 show two different views (a ground track view and a
three-dimensional view) of a hypothetical East Coast engagement with at least
two SLS opportunities from CONUS-based interceptors, with the first engage-
ment just after apogee. If the same interceptor type were also based in Poland,
two additional ascent shots would be possible. Table 5-3 displays an event time-
line for this case.
Figure 5-16 displays the intercept event times for each shot in the four-shot
SLS sequence and the apogee point looking down along the ground track of the
threat trajectory. In this example the first two shots are taken from the Poland
interceptor site prior to apogee. The first shot, if it misses or sees more than one
credible object, can be considered as a pathfinder for the second shot in the SLS
firing doctrine. Likewise, this discrimination data stream cascades downward to
each succeeding shot in the SLS sequence. The continuous ground-based radar
(GBR) track and hit/kill assessment data along with data from the earlier inter-
ceptor sensor TOM are fused by the BMC2 and provided to each interceptor in
the SLS succession until a kill is assessed as complete or until the battle space
is exhausted. The last two shots, if needed, come from a CONUS East Coast
interceptor site, in this example at Caribou, Maine.
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166 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
Figure 5-17 displays the same engagement using a three-dimensional pro-
jection to give an altitude perspective along with additional data indicating the
geometry between the line-of-sight (LOS) at the KV sensor acquisition of the
target complex and the time to go (T2Go) to intercept of the target. The intercep-
tor total time of flight (ITOF) from launch to intercept of the target is also shown.
The divergent blue line is the LOS to the target, and the red line is the path of
the interceptor KV to the target. The angle at which the KV trajectory (red) ap-
proaches the target trajectory (yellow) gives an indication of the crossing angle
between the KV and target. Crossing angles of less than 90 degrees result in
head-on intercepts, and crossing angles greater than 90 degrees are referred to as
tail-chase intercepts. Head-on intercepts are preferred due to their higher closing
velocity, which results in much greater energy exchange between the colliding
bodies and therefore a much more lethal engagement.
Table 5-3 presents a more detailed timeline and provides metrics for an en-
gagement such as this. It can be seen from an examination of the event timeline
that a significant battle space is left after the fourth shot in the SLS engagement
sequence. This provides a lot of flexibility in the timing of the actual shots
and allows more time for certain functions that might be impacted by natural
backgrounds and unexpected events during the course of the engagement. For
example, when the first interceptor first acquires the threat complex at 339 sec
and tracks long enough to determine that there is more than one credible object
in the threat, this TOM information can be transmitted back to the BMC2 and an
additional interceptor(s) can be launched before the first interceptor to make its
intercept. This strategy is referred to as shoot-engage-shoot (SES) and can make
use of the approximately 150-160 sec of battle space available before the first
interceptor reaches its intercept point. Likewise, if the first interceptor should
fail at any point in its flight, and this information is available to the BMC2, it
can be replaced immediately by another interceptor using a strategy referred to
as shoot-fail-shoot (SFS).
Effect of Time Delays Between Planned SLS Engagements
If the second shot is taken at its normal planned time, based on SLS, it would
be launched at 546 sec and would intercept at 742 sec in the mission timeline.
This assumes a 30-sec time delay for XBR tracking and kill assessment between
the first intercept and launch of the second interceptor. Kill assessment is based
on real-time analysis of X-band radar track and debris data to determine if a
credible threat on a continuing ballistic path survived and should be engaged. It
is noted that the closing velocity for the second intercept is about 8.6 km/sec and
the crossing angle is about 81 degrees, with a total time of flight from launch to
intercept of 196 sec at a fly-out ground range of only 302 km. Additional analysis
shows the second interceptor launch could be delayed by as much as 2 min (120
sec), at 666 sec in the timeline, and still engage the target with a closing velocity
of about 4.8 km/sec and a crossing angle of 127 degrees (a tail-chase geometry) at
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RECOMMENDED PATH FORWARD 167
931 sec in the mission timeline compared to the 742 sec in the normal sequence.
When analysis is taken to the kinematic limit of being able to engage with the
second shot, it shows the maximum additional delay between the first intercept
and launch of the second interceptor is 3 min (180 sec), resulting in a second
interceptor launch at 726 sec and an intercept at 1,353 sec. This results in a clos-
ing velocity of only 1.7 km/sec and a crossing angle of 165 degrees (a severe
tail chase) and may not have enough closing velocity to effect a lethal collision
with the target.
Interceptor SFS Replacement in Each Layer
The timeline that results if this additional 120-sec interceptor launch delay is
flowed down to each layer of the four-shot SLS sequence can be compared with
the timeline of Table 5-3.
Launch Intercept Closing Velocity Crossing Angle
Sequence (sec) (sec) (km/sec) (deg)
First shot 190 516 11.3 35.7
Second shot 666 931 4.8 127.0
Third shot 1,081 1,525 11.5 10.3
Fourth shot 1,675 1,811 12.2 34.2
Figure 5-18 displays the ground track view of the baseline engagement (same
as Figure 5-16) and compares it with the case of 120-sec additional time delays
between intercept and launch of each remaining interceptor in the four-shot SLS
sequence. In short, if the second interceptor is launched in a normal SLS sequence
and there is a failure during boost phase or even a KV sensor failure at target
acquisition, at 626 sec into the mission timeline, there is still ample time to launch
a replacement interceptor in an SFS mode and not eliminate the downstream op-
portunities for the third and fourth shots in a continuation of the SLS sequence.
In fact, were this same kind of interceptor failure to occur at each layer in the
four-shot sequence there still would be enough battle space in each layer for an
SFS replacement, as shown in the bottom part of Figure 5-18.
Effect of Individual and Multiple Radar Outages on SLS Performance
The issue of radar outage is a likely source of single-point failure in a missile
defense system. However, with proper layering of critical radars, the concept is
very resilient to the loss of one, two, and even three radars. Using an approach
similar to that in the interceptor failure example, the result of losing one, two,
or three of the four X-band radars at play in this scenario—Azerbaijan TPY-2
(XBR); Fylingdales, U.K. (GBX); Thule, Greenland (GBX); and Cape Cod,
Massachusetts (GBX). The Azerbaijan TPY-2 FBX could just as well have been
placed in eastern Turkey for the purposes of this analysis.
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168 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
BASELINE ENGAGEMENT
GBX
GBX
TPY-2
POLAND
Interceptor
Site
Apogee at 1st Shot (SLS)
MAINE 1,081 sec Intercept Point
Interceptor 2nd Shot (SLS) (at 516 sec)
Site Intercept Point
(at 742 sec)
Total Time 3rd Shot (SLS) GBX
(2,050 sec) 4th Shot (SLS) Intercept Point
Intercept Point (at 1,381 sec)
GBX (at 1,682 sec)
ADDITIONAL 120 SECOND SLS LAUNCH DELAY
1st Shot (SLS)
Intercept Point
120 sec additional time delay between (at 516 sec)
intercept and launch of all following SLS shots
2nd Shot (SLS)
Intercept Point
(at 931 sec)
3rd Shot (SLS)
4th Shot (SLS) Intercept Point
Intercept Point (at 1,525 sec)
(at 1,811 sec)
FIGURE 5-18 Example of Middle East to CONUS East Coast four-shot SLS engamement
scenario (ground track view).
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RECOMMENDED PATH FORWARD 169
Single Radar Out
• Case 1, Figure 5-19. Azerbaijan out (earliest first-shot commit): Fyling-
dales GBX fills this role with the following result (can still get four shots, one
from Poland and three from Maine):
Launch Intercept Closing Velocity Crossing Angle
Sequence Site (sec) (sec) (km/sec) (deg)
First shot Poland 474 690 9.5 67.4
Second shot Poland Not enough battle space for second shot Poland site
Second shot Maine 720 1,357 11.1 8.3
Third shot Maine 1,387 1,671 11.9 15.3
Fourth shot Maine 1,701 1,825 12.1 39
• Case 2, Figure 5-20 (two possibilities). Fylingdales out (first-shot kill
assessment and second- and third-shot commit).
—Thule GBX fills the third-shot commit role with the following result:
Launch Intercept Closing Velocity Crossing Angle
Sequence Site (sec) (sec) (km/sec) (deg)
First shot Poland 190 690 9.5 67.4
Second shot Poland No radar for first-shot kill KA (use KV TOM and hit/miss report)
Third shot Maine 1,373 1,664 11.9 14.9
Fourth shot Maine 1,694 1,821 12.1 37.5
NOTE: KA, kill assessment.
FIGURE 5-19 Case 1: Azerbaijan radar out.
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170
FIGURE 5-20 Case 2: Fylingdales radar out.
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—Cape Cod GBX fills the third-shot commit role with the following
result:
Launch Intercept Closing Velocity Crossing Angle
Sequence Site (sec) (sec) (km/sec) (deg)
First shot Poland 190 516 11.3 35.7
Second shot Poland No radar for first shot KA (use KV TOM and hit/miss report)
Third shot Maine 1,481 1,716 12.1 18.5
Fourth shot Maine 1,746 1,849 11.7 50.3
As shown in the engagement map in Figure 5-20, with the Fylingdales radar
out, the second shot comes out of the interceptor site in Maine based on track
data from either Thule (launch at 1,373 sec) or from Cape Cod 108 sec later
(1,481 sec). This second shot is provided the TOM and hit/miss data from the
first interceptor out of Poland even though no radar KA data are available. This
second shot is not a true SLS engagement, but it is given significant new data by
the BMC2 from the first shot KV sensor combined with the new Thule and/or
Cape Cod GBX track data and can be considered an SLS shot. The third shot, if
necessary, is a true SLS engagement.
Two Radars Out
• Case 3, Figure 5-21. Azerbaijan and Fylingdales radars out: (1) Azer-
baijan out (earliest first-shot commit) and (2) Fylingdales GBX out (first- and
THULE Azerbaijan
GBX (TPY-2)
OUT
FYL
GBX
OUT
1st Shot
Intercept
2rd Shot (SLS) at 1,664 sec
Intercept
CAPE COD at 1,821 sec
GBX
FIGURE 5-21 Azerbaijan and Fylingdales radar out.
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172 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
second-shot commit, third-shot KA). Thule fills third-shot commit role with the
following result:
Launch Intercept Closing Velocity Crossing Angle
Sequence Site (sec) (sec) (km/sec) (deg)
First shot Poland No radar for interceptor commit out of Poland (satellite)
Second shot Poland No radar for interceptor commit out of Poland (satellite)
Third shot Maine 1,373 1,664 11.9 14.9
Fourth shot Maine 1,694 1,821 12.1 37.5
Figure 5-21 shows the system rollback to a single SLS capability when both
of the forward-based radars are out (Azerbaijan and Fylingdales). In this case the
first-shot commit is provided by the Thule GBX radar.
Three Radars Out
• Case 4. Azerbaijan, Fylingdales, and Thule radars out: (1) Azerbaijan
out (earliest first-shot commit), (2) Fylingdales GBX out (first- and second-shot
commit, third-shot KA, and (3) Thule out (third-shot commit). Cape Cod fills
third shot commit role with the following result:
Launch Intercept Closing Velocity Crossing Angle
Sequence Site (sec) (sec) (km/sec) (deg)
First shot Poland No radar for interceptor commit out of Poland (satellite)
Second shot Poland No radar for interceptor commit out of Poland (satellite)
Third shot Maine 1,481 1,716 12.1 18.5
Fourth shot Maine 1,746 1,849 11.7 50.3
If Azerbaijan, Fylingdales, and Thule are all out, then Cape Cod is left to
provide the tracking data necessary for a two-shot SLS engagement very similar
to the one just discussed.
FINAL COMMENTS
Chapter 5 is intended to recommend the path forward for the United States to
develop the most effective BMD capability—particularly for homeland defense—
taking into account the surrounding operational, technical, and cost issues. This
will take time, money, and careful testing, but unless this is done, the system will
not be able to work against any but the most primitive attacks. The recommended
path forward, GMD-E, involves a smaller, shorter burn interceptor configuration
building on development work already done by MDA under the KEI program but
with a different front end. The heavier, more capable KV with a larger onboard
sensor provides the capabilities absent in the current GMD system but responsive
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RECOMMENDED PATH FORWARD 173
to the recommended CONOPS discussed earlier. This evolved GBI would first
be deployed at a new third site in the northeast United States along with five
additional X-band radars using doubled THAAD AN/TPY-2 radars integrated
together at each early warning system (EWS) site and at Grand Forks, North
Dakota. At a later time, the more capable interceptor would be retrofitted into the
silos at FGA, with the existing GBIs diverted to the targets program supporting
future operational flight tests.
As discussed throughout this report, missile defense is at a critical point. The
title of this report, Making Sense of Ballistic Missile Defense: An Assessment of
Concepts and Systems for U.S. Boost-Phase Missile Defense in Comparison to
Other Alternatives, underscores this critical point and the objectives put forth by
both the current and previous administrations. While the current administration
will need to consider the 20-yr LCCs associated with present and proposed BMD
systems as discussed and assessed throughout this report, it will also need to be
mindful of the funding wedge for the next 5 years. Figure 5-22 displays the MDA
cummulative annual funding wedge for the FY 2012 future years defense plan
(FYDP) submitted by DOD to the Congress. Here, the cumulative total obligation
authority (TOA) from FY 2010 through FY 2016 is about $45 billion. It includes
approximately $1.3 billion for the precision tracking and surveillance system
(PTSS); $1.6 billion for BMC3; and $500 million for advanced technology.
FIGURE 5-22 MDA funding wedge for FYDP submitted to Congress in FY 2011. The
activities with an asterisk include funds for PAA Phases I through III.
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174 MAKING SENSE OF BALLISTIC MISSILE DEFENSE
Based on Figure 5-22 and the results presented in this report, the committee
concludes as follows with respect to the immediate future:
1. The current homeland defense plan, which consists of GMD augmented
by early intercept capabilities from Europe, is very expensive and has limited
effectiveness.
2. PTSS costs four times as much to acquire and four to five times as much
over its 20-yr life cycle as the X-band radar suite recommended and it offers
less value.
3. GMD-E has substantially lower LCC and provides the most effective
capabilities. It can be implemented within the same TOA over the next 5 years
with an initial operational capability of FY 2019 provided some low pay-off
programs are terminated and others are not started.
4. GMD-E’s predicted capability for SLS over most of North America
relieves the requirement, necessitated by current GMD limitations, for early in-
tercepts from Europe against threats from the Middle East toward North America.
This decoupling allows independent decisions for the later phase of European
defense or any other new task.
