fThis page left intentionally blank2019 MISSILE DEFENSE REVIEWOFFICE OF THE SECRETARY OF DEFENSE

This page left intentionally blankExecutive Summary
I. Introduction
The 2017 National Security Strategy (NSS) states, “Our fundamental responsibility is to protect
the American people, the homeland, and the American way of life.” Missile defense is an
essential component of U.S. national security and defense strategies. It contributes to thedeterrence of adversary aggression and the assurance of allies and partners. It also strengthens
U.S. diplomacy, protects against missile attacks to limit damage, supports U.S. military
operations if deterrence fails, hedges against future uncertainties and risks, and helps topreserve U.S. and allied freedom of action to meet and defeat regional adversary aggression.
This 2019 Missile Defense Review (MDR) is consistent with the 2017 NSS, the 2018 National
Defense Strategy (NDS), and the 2018 Nuclear Posture Review (NPR). It describes the policies,
strategies, and capabilities that will guide the Department of Defense (DoD) missile defense
programs to counter the expanding missile threats posed by rogue states and revisionist powers
to us, our allies, and partners, including ballistic and cruise missiles, and hypersonic vehicles.
It recognizes and highlights the important changes that have taken place in the security
environment since the previous 2010 Ballistic Missile Defense Review was conducted, as well as
the considerable uncertainties about the future threat environment.
This 2019 MDR is based on recognition that the threat environment is markedly moredangerous than in years past and demands a concerted U.S. effort to improve existing
capabilities for both homeland and regional missile defense. This effort will include a vigorous
science and technology research program in addition to the exploration of innovative concepts
and advanced technologies that have the potential to provide more cost-effective U.S. defenses
against expanding missile threats.
This 2019 MDR also emphasizes that the missile threat environment now calls for acomprehensive approach to missile defense against rogue state and regional missile threats.
This approach integrates offensive and defensive capabilities for deterrence, and includes active
defense to intercept missiles in all phases of flight after launch, passive defense to mitigate theeffects of missile attack, and attack operations during a conflict to neutralize offensive missile
threats prior to launch.

II. The Evolving Threat Environment
The 2018 NDS emphasizes that today’s security environment is “more complex and volatile
than any we have experienced in recent memory.” Potential adversaries are investing
substantially in their missile capabilities. They are expanding their missile capabilities in threeI
MISSILE DEFENSE REVIEWdifferent directions simultaneously: increasing the capabilities of their existing missile
systems; adding new and unprecedented types of missile capabilities to their arsenals; and,integrating offensive missiles ever more thoroughly into their coercive threats, military
exercises, and war planning.
New ballistic missile systems feature multiple independently targetable reentry vehicles(MIRV) and maneuverable reentry vehicles (MaRV), along with decoys and jamming devices.
Russia and China are developing advanced cruise missiles and hypersonic missile capabilities
that can travel at exceptional speeds with unpredictable flight paths that challenge existing
defensive systems. These are challenging realities of the emerging missile threat environmentthat U.S. missile defense policy, strategy, and capabilities must address.

Current and Emerging Missile Threats to the American Homeland
North Korea. While a possible new avenue to peace now exists with North Korea, it continues
to pose an extraordinary threat and the United States must remain vigilant. In the past, North
Korea frequently issued explicit nuclear missile threats against the United States and allies, all
the while working aggressively to field the capability to strike the U.S. homeland with nucleararmed ballistic missiles. Over the past decade, it has invested considerable resources in its
nuclear and ballistic missile programs, and undertaken extensive nuclear and missile testing inorder to realize the capability to threaten the U.S. homeland with missile attack. As a result,North Korea has neared the time when it could credibly do so.
Iran. Iran views U.S. influence in the Middle East as the foremost barrier to its goal of
becoming the dominant power in that region. One of Iran’s primary tools of coercion andforce projection is its missile arsenal, which is characterized by increasing numbers, as well as
increases in accuracy, range, and lethality. Iran has the largest ballistic missile force in the
Middle East and continues the development of technologies applicable to intercontinentalrange missiles capable of threatening the United States. Its desire to have a strategic counterto the United States could drive it to field an ICBM, and progress in its space program could
shorten the pathway to an ICBM.
Russia. Russia considers the United States and the North Atlantic Treaty Organization(NATO) to be the principal threat to its contemporary revisionist geopolitical ambitions androutinely conducts exercises involving simulated nuclear strikes against the U.S. homeland.
Russian strategy and doctrine emphasize the coercive and potential military uses of nuclear
weapons, particularly including nuclear-armed, offensive missiles, and has sought to enable
this strategy through a comprehensive modernization of its strategic and theater missile
arsenals. As counted under the 2010 New START Treaty, Russia is permitted a total of 700
deployed ICBMs, sea-launched ballistic missiles (SLBM), and heavy bombers, and 1,550
deployed strategic nuclear warheads. Russian leaders also claim that Russia possesses a newclass of missile, the hypersonic glide vehicles (HGV), which maneuver and typically travel atvelocities greater than Mach 5 in or just above the atmosphere.
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MISSILE DEFENSE REVIEWChina. China seeks to displace the United States in the Indo-Pacific region and reorder theregion to its advantage. Offensive missiles play an increasingly prominent role in China’s
military modernization, its coercive threats, and efforts to counter U.S. military capabilities
in the Indo-Pacific. It has deployed 75-100 ICBMs, including a new road-mobile system and a
new multi-warhead version of its silo-based ICBM. Beijing also now possesses 4 advanced JINclass ballistic missile submarines (SSBN), each capable of carrying 12 new submarine-launchedballistic missiles (SLBM), the CSS-N-14. Consequently, China can now potentially threaten
the United States with about 125 nuclear missiles, some capable of employing multiple
warheads, and its nuclear forces will increase in the coming years. Beijing also is developing
advanced technologies, such as MaRVs and HGVs.
While the United States relies on deterrence to protect against large and technicallysophisticated Russian and Chinese intercontinental ballistic missile threats to the U.S.
homeland, U.S. active missile defense can and must outpace existing and potential rogue state
offensive missile capabilities. To do so, the United States will pursue advanced missile defense
concepts and technologies for homeland defense.

Missile Threats to U.S. Forces Abroad, Allies, and Partners
Potential adversaries are also fielding an increasingly diverse, expansive, and modern range ofregional offensive missile systems that can threaten U.S. forces abroad, allies, and partners.
These include multiple types of short-, medium-, and intermediate-range missiles intended toprovide coercive political and military advantages in regional crises or conflict. Expanding andmodernizing U.S. regional missile defenses is an imperative to meet these ongoing adversary
advancements in their regional offensive missile systems.
North Korea. Over the past decade, North Korea accelerated its efforts to field missiles capableof threatening deployed U.S. forces, allies, and partners in the region. Since 2015, North
Korea test-launched, from numerous locations throughout North Korea, over two dozen
regional missiles. It has fielded more regional missiles and diversified its already large regionalballistic missile force, including delivery systems with road-mobile and submarine launching
platforms.
These wide-ranging North Korean offensive missile systems have given North Korea thecapability to strike U.S. territories, including Guam, U.S. forces abroad, and allies in the
Pacific Ocean. They are the tools North Korea has used to issue coercive nuclear preemptive
threats, and potentially could use to employ nuclear weapons in the event of conflict in Asia.
Iran. Iran continues to develop more sophisticated missiles with improved accuracy, range,
and lethality. It fields an array of increasingly accurate short- and medium-range ballistic
missile systems capable of threatening deployed U.S. forces, allies, and partners. Iran’s
medium-range systems can threaten targets from Eastern Europe to South Asia, and Iran has
transferred missile systems to terrorist organizations, which in turn have used Iranian-suppliedIII
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missiles against U.S. Middle East allies and partners. It has also flight-tested a short-range
ballistic missile (SRBM) in an anti-ship role that can threaten U.S. and allied naval vessels in
the Arabian Gulf and Strait of Hormuz, and has displayed a land-attack cruise missile (LACM)
that has a claimed range of 2000 kilometers (km).
Russia. Moscow is fielding an increasingly advanced and diverse range of nuclear-capableregional offensive missile systems, including missiles with unprecedented characteristics ofaltitude, speed, propulsion type, and range. These missile systems are a critical enabler ofRussia’s coercive escalation strategy and nuclear threats to U.S. allies and partners. It isdeveloping a new generation of advanced regional ballistic and cruise missiles that support its
anti-access/area denial (A2/AD) strategy intended to defeat U.S. and allied will and capability
in regional crises or conflicts. Since 2015, Russia has demonstrated its advanced cruise missile
capability by repeatedly conducting long-range precision strikes into Syria, and has fielded aground-launched, intermediate-range cruise missile, the SSC-8, in violation of theIntermediate-Range Nuclear Forces (INF) Treaty.
China. China is also developing missile capabilities intended to deny the United States thecapability and freedom of action to protect U.S. allies and partners in Asia. A key componentof China’s military modernization is its conventional ballistic missile arsenal designed toprevent U.S. military access to support regional allies and partners. China is improving its
ability to strike regional targets, such as U.S. bases and naval assets, at greater ranges with theaddition of the growing number of medium- and intermediate-range ballistic missiles. This
includes sophisticated anti-ship ballistic missiles that pose a direct threat to U.S. aircraft
carriers.
China also has ground- and air-launched LACMs, and is developing HGVs and new MaRVs.
These and other wide-ranging developments in China’s expansive offensive missile arsenalpose a potential nuclear and non-nuclear threat to U.S. forces deployed abroad, and are ofacute concern to U.S. allies and partners in the Indo-Pacific region.

Potential Adversary Missile Defense and Antisatellite (ASAT) Advancements
Despite frequently criticizing the United States and allies for developing and fielding missile
defense systems, potential adversaries have long made substantial investments in their own
missile defense systems. Russia and China are also developing ASAT capabilities that could
threaten U.S. space-based assets.
For example, Russia maintains and modernizes its longstanding strategic missile defense
system deployed around Moscow, including 68 nuclear-armed interceptors, and has fielded
multiple types of shorter-range, mobile missile defense systems throughout Russia. In
addition, Russia is developing a diverse suite of ground-launched and directed-energy ASAT
capabilities, and continues to launch “experimental” satellites that conduct sophisticated onorbit activities to advance Russian counterspace capabilities.
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MISSILE DEFENSE REVIEWChina is aggressively pursuing a wide range of mobile air and missile defense capabilities,
including the purchase of S-400 systems from Russia, each with four interceptor missiles, andis developing additional theater ballistic missile defense systems. China also has announced
that it is testing a new mid-course missile defense system. Further, China is developing a suiteof antisatellite weapons, continues to launch “experimental” satellites that conductsophisticated on-orbit activities to advance counterspace capabilities, and has conducted
multiple ASAT tests using ground-launched missiles.
North Korea has acquired Russian missile defense technology and is developing its own mobile
missile defense capabilities, specifically, a mobile air and missile defense system. While
indigenously produced, its interceptors and radar system share similarities with Russian
systems.
Russia has been instrumental in Iran’s development of a mobile air and missile defense
capability. In 2016 Russia delivered 16 S-300 launch vehicles to Iran, each armed with fourinterceptors. Iran also is developing its own missile defense system, the Bavar 373, to provide
additional missile defense capability.

III. Roles, Policy, and Strategy
Diverse Roles of Missile Defense
The diverse roles of missile defense advance the national strategy and goals articulated in the2017 NSS, 2018 NDS, and 2018 NPR:
The protection of the U.S. homeland, forces abroad, allies, and partners. If potential adversaries
miscalculate and deterrence fails, missile defense limits the number of adversary missile
warheads that strike their targets. This is critical to defending the territorial integrity of theUnited States, saving lives, limiting damage to critical infrastructure, and enabling operational
success in regional conflict. Today’s U.S. missile defenses provide significant protection
against potential North Korean or Iranian ballistic missile strikes against the U.S. homeland,
and will improve as necessary to stay ahead of missile threats from rogue states.
The deterrence of attacks against the United States, allies, and partners. Missile defense contributes
directly to tailored U.S. deterrence strategies for regional missile threats and for rogue state
ICBM threats to the U.S. homeland. Missile defenses can undermine potential adversaries’
confidence in their ability to achieve their intended political or military objectives throughmissile threats or attacks. An adversary’s uncertainty regarding the effectiveness of its attack
plans, combined with the prospect of an effective U.S. response to aggression, provide strong
incentives for adversary restraint if ever contemplating missile attacks. By shaping anadversary’s decision calculus in this way, missile defense diminishes the perceived value of
missiles as tools of coercion and aggression, thus contributing to deterrence. Missile defense
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also provides additional time and options for U.S. leaders when considering their options forresponding to aggression, and thus contribute to the U.S. ability to respond to and stabilize
crises or conflicts.
The assurance of allies. Missile defense plays an increasingly important role in assuring allies andpartners, and reinforcing the indivisibility of U.S. and allied security. It does so by helping toprotect allied territory, strengthening U.S. military operations in support of allies and partners
abroad, and, by helping to counter adversary strategies attempting to coerce the United States,
allies and partners with missile threats. U.S. missile defense deployments and cooperative
missile defense activities strengthen relations with allies and partners and reduce theirvulnerability to coercive threats and attacks. They also provide opportunities for cooperative
allied burden-sharing and defense collaboration.
Strengthening U.S. diplomatic efforts in peacetime and crises. The United States is committed to
diplomatic efforts that advance U.S., allied, and partner security. Missile defenses provide
U.S. leaders a position of strength from which to engage potential adversaries diplomaticallyin peacetime or crises. This was important in the past, and likely will be so in the future.
The United States also is committed to non-proliferation. Rogue states seek to develop missile
delivery systems through illicit procurement pathways for the acquisition of criticaltechnologies and components, often in violation of United Nations Security Council
resolutions. The proliferation challenge posed by potential adversaries may worsen in the
future and lead to diverse unanticipated missile threats to the United States, allies, andpartners.
As U.S. missile defense capabilities improve to stay ahead of missile threats, they may also help
dissuade missile proliferation among potential adversaries by reducing the political and military
value of their missiles. And, by supporting the credibility of U.S. assurance commitments,
missile defense can contribute to U.S. nonproliferation goals by assuring allies and partners of
their security in the absence of their own independent nuclear capabilities.
Missile Defenses are Stabilizing. Missile defense capabilities provide the U.S., allies, and partners
the ability to prevent or limit damage from an adversary offensive missile strike. They provide
an additional option to offensive strikes to prevent damage to the United States, deployed
forces, allies, and partners.
Hedging against future risks. The pace and scale of proliferation and future missile threats is
uncertain. U.S. missile defense capabilities and planning must take into account the potential
for continuing missile proliferation among potential adversaries, including the proliferation ofadvanced missile capabilities. Hedging strategies incorporating missile defense help reducerisk and mitigate offensive missile threats that emerge over time, both geopolitical andtechnical. The U.S. capacity to hedge contributes to deterrence and to the U.S. diplomatic
position of strength by helping to reduce potential adversary confidence of a political or
military advantage via an expansion or even “breakout” of its missile capabilities. This hedging
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against possible future missile threats also contributes to the assurance of allies and partners bystrengthening their confidence that U.S. missile defense capabilities will not be overtaken by
adversary offensive threat developments.
Enabling Regional and Transregional Military Operations. Missile defense supports U.S. andcoalition military operations across multiple regions. It helps preserve U.S. freedom of action
by limiting adversary capabilities to inhibit or disrupt U.S. regional military operations abroad
through missile attacks on U.S. forward deployed forces, allies, or critical in-theater
infrastructure. Indeed, missile defense is an element of the U.S. capability to counter A2/AD
strategies that seek to deter or prevent the United States from supporting allies in contested
regions. This role for missile defense also provides critical support for the deterrence of
attacks and the assurance of allies and partners.

Principles Governing U.S. Missile Defense
U.S. Homeland Missile Defense Will Stay Ahead of Rogue States’ Missile Threats. It is imperative that
U.S. missile defense capabilities provide effective, continuing protection against rogue state
missile threats to the homeland, now and into the future. The United States is technicallycapable of doing so, and has adopted an active missile defense force-sizing measure forprotection of the homeland. DoD will develop, acquire, and maintain the U.S. homeland
missile defense capabilities necessary to effectively protect against possible missile attacks on
the homeland posed by the long-range missile arsenals of rogue states, defined today as North
Korea and Iran, and to support the other missile defense roles identified in this 2019 MDR.
This force-sizing measure for active U.S. missile defense will require the examination andpossible fielding of advanced technologies to provide greater efficiencies for U.S. active missile
defense capabilities, including space-based sensors and boost-phase defense capabilities. It calls
for a missile defense architecture that can adapt to emerging and unanticipated threats,
including by adding capacity and the capability to surge missile defense as necessary in timesof crisis or conflict.
Consequently, the United States will not accept any limitation or constraint on thedevelopment or deployment of missile defense capabilities needed to protect the homelandagainst rogue missile threats. Accepting limits now could constrain or preclude missile defense
technologies and options necessary in the future to effectively protect the American people.
U.S. missile defense capabilities will be sized to provide continuing effective protection of the
U.S. homeland against rogue states’ offensive missile threats. The United States relies on
nuclear deterrence to address the large and more sophisticated Russian and Chineseintercontinental ballistic missile capabilities, as well as to deter attacks from any source
consistent with long-standing U.S. declaratory policy as re-affirmed in the 2018 NPR.

VIIMISSILE DEFENSE REVIEWMissile Defense Will Defend U.S. Forces Deployed Abroad and Support the Security of Allies and Partners.
Defending U.S. forces abroad, allies, and partners, and helping them better defend themselves
against the full range of regional missile threats is a vital element of U.S. regional security
strategy in Europe, Asia, and the Middle East. The United States will strengthen regional
missile defense capabilities and cooperative relationships with allies and partners on a broad
range of missile defense activities, and encourage additional allied investments in missile
defense, including co-development and co-production efforts to better share the burden ofcommon defense. The United States will not accept any limitations on the development or
deployment of missile defense capabilities.
The United States Will Pursue New Concepts and Technologies. Modernization and innovation are
critical to ensure the continuing effectiveness of missile defenses. The United States will invest
in advanced technologies to meet the increasingly complex threats posed by larger missile
inventories and improved countermeasures. Successful science and technology initiatives maylead to operational prototypes that will be evaluated outside the standard acquisition process
in order to develop successful technologies more quickly, while also ensuring that unsuccessful
efforts are avoided before consuming scarce funding.

Elements of Missile Defense Strategy
Comprehensive Missile Defense Capabilities. Effective deterrence is the preferred strategy toprevent missile attack. However, a broader approach is required to address the increasingly
complex missile threat environment. The United States will field, maintain, and integrate
three different means of missile defense to identify and exploit every practical opportunity todetect, disrupt, and destroy a threatening missile prior to and after its launch. These include:
first, active missile defense to intercept adversary missiles in all phases of flight; second, passive
defense to mitigate the potential effects of offensive missiles; and third, if deterrence fails,
attack operations to defeat offensive missiles prior to launch.
This multi-layered approach to preventing and defeating missile attacks will move the UnitedStates towards a more flexible and balanced overall defense posture that provides the broadest
set of options in a crisis or conflict and improves the overall likelihood of countering offensive
missile attacks successfully. To do so, the United States will integrate active missile defenses
with intelligence, surveillance, and reconnaissance (ISR) and strike capabilities to counterregional offensive missile threats and rogue missile threats to the homeland.
Flexibility and Adaptability. With more than 20 states possessing offensive missile technology,
and many expanding and modernizing their capabilities, it is clear that future adversary
offensive missile threats and U.S. defensive goals will be diverse and dynamic. Flexibility andadaptability will enable the United States to tailor its missile defense strategy to potential
adversaries to deny them the benefits they seek from offensive missile threats or employment.
Consistent with an emphasis of the 2018 NDS, this MDR emphasizes the need for flexibility
and adaptability in U.S. missile defense design, research, and acquisition programs. Because
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MISSILE DEFENSE REVIEWthe U.S. missile defense posture must be capable of being flexibly deployable and adaptable tomeet future threats as they emerge, DoD will continue to seek ways to shorten the timerequired to develop and field responsive missile defense systems.
Tighter Offense-Defense Integration and Interoperability. The United States must maintain theability to deploy rapidly and sustain its operational plans in an A2/AD environment in which
adversaries seek to use ballistic and cruise missiles to coerce both in peacetime and crisis, andto overwhelm U.S. forces in the event of conflict. Integrated missile defense plans, force
management, and operations support will emphasize global coordination and enableengagement from the best interceptor using the best sensor data. Toward that end, it isnecessary to pursue more integrated approaches to the missile defense mission that leverage
the full range of assets available.
The United States will pursue greater integration of attack operations with active and passive
missile defenses, and homeland and regional missile defense assets. In addition, as allied andpartner missile defense capabilities grow in size and sophistication, a strong commitment tointeroperability will maximize their contribution to the missile defense mission and enable amore effective collective response to missile attacks.
Importance of Space. The exploitation of space provides a missile defense posture that is more
effective, resilient and adaptable to known and unanticipated threats. Space-based sensors, forexample, can monitor, detect and track missile launches from locations almost anywhere on
the globe – they enjoy a measure of flexibility of movement that is unimpeded by theconstraints that geographic limitations impose on terrestrial sensors, and can provide “birth todeath” tracking that is extremely advantageous.
As rogue state missile arsenals develop, the space-basing of interceptors may provide theopportunity to engage offensive missiles in their most vulnerable initial boost phase of flight,
before they can deploy various countermeasures. Space-basing may increase the overall
likelihood of successfully intercepting offensive missiles, reduce the number of U.S. defensive
interceptors required to do so, and potentially destroy offensive missiles over the attacker’s
territory rather than the targeted state. DoD will undertake a new and near-term examinationof the concepts and technology for space-based defenses to assess the technological andoperational potential of space-basing in the evolving security environment.

IV. U.S. Missile Defense Programs and Capabilities
The Ballistic Missile Defense System (BMDS) provides active defense of the U.S. homelandand deployed forces, allies, and partners. The BMDS is an integrated, layered ballistic missile
defense architecture that provides multiple opportunities to destroy missiles and theirwarheads before they can reach their targets. The architecture includes land-, sea-, and spacebased elements to track, target, and destroy offensive ballistic missiles of different ranges,
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MISSILE DEFENSE REVIEWspeeds, and sizes after their launch. Some elements of the BMDS also have capabilities todefend against cruise missiles.
The United States will develop innovative approaches and new technologies that stay ahead of
the rapid advances in rogue states’ offensive missile threats to the U.S. homeland and provide
the needed defense against regional missile threats. To do so, DoD will increase investments
in and deploy new technologies and concepts, and adapt existing weapons systems to field newcapabilities rapidly at lower cost. In addition, DoD will leverage investments in existing
defensive systems and the knowledge gained from prior missile defense research anddevelopment to expand U.S. defensive capabilities to new domains, achieve greater
integration, and strengthen U.S. capabilities for attack operations to destroy offensive missiles
prior to their launch.

U.S. Homeland Defense
Defending the U.S. homeland against missile attack helps to deter adversaries, assure allies andpartners, and provide U.S. leaders with a position of strength to engage adversaries and project
power in support of national objectives. The United States is protected against a limited ICBM
attack as a result of investments made in the Ground-Based, Mid-Course Defense (GMD)
system. The GMD system is designed to defend against the existing and potential ICBM threat
from rogue states such as North Korea and Iran, but in the event of conflict, it would defend,
to the extent feasible, against a ballistic missile attack upon the U.S. homeland from any
source.
The GMD system engages adversary long-range ballistic missiles in the mid-course phase offlight using Ground-Based Interceptors (GBI). GBIs destroy attacking missiles by striking
them at high speeds with a kinetic kill vehicle. Forty GBIs are deployed at Ft. Greely, Alaska,
and four at Vandenberg Air Force Base, California.
DoD is investing in the expansion and modernization of current U.S. homeland missile defense
capabilities to help counter advanced offensive missile threats for the next decade. Thisdecision is in line with Congressional intent as expressed in the 2017 National Defense
Authorization Act that we will “maintain and improve an effective, robust layered missile
defense system capable of defending the territory of the United States, allies, deployed forces,
and capabilities against the developing and increasingly complex ballistic missile threat.” We
are now improving the reliability and lethality of current missile defense forces and enhancing
the ability of U.S. active missile defenses to track, target, and destroy adversary offensive
missiles with greater precision. These efforts and priorities are reflected in the
Administration’s recent budget requests and actions. For example, Congress appropriatedapproximately $15.3 billion in FY18 for homeland and regional missile defense, including an
emergency appropriation of $4 billion to further expand and enhance U.S. missile defense
capabilities against North Korean missile threats to the U.S. homeland, forces abroad, allies,
and partners.
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MISSILE DEFENSE REVIEWDoD programs to improve the capability and reliability of the GMD system include equipping
recently-deployed GBIs with an advanced booster and a more capable Exoatmospheric Kill
Vehicle (EKV). DoD is also building a new GBI interceptor field in Ft. Greely, Alaska, andwill increase the number of deployed GBIs from 44 to 64 beginning as early as 2023, and isstrengthening the performance of existing missile defense sensors and fielding new sensors foreven greater discrimination capability. Taken together, these enhancements will result in
improved performance, reliability, and lethality against offensive ballistic missile threats to the
U.S. homeland.
More complex offensive missile threats to the homeland, such as HGV and advanced cruise
missiles, are on the horizon. DoD is enhancing ways to collect and process information fromexisting space-based and terrestrial sensors to track current and emerging cruise missile and
HGV threats. Enhancing our ability to track these emerging threats will make defending
against cruise missile and HGV threats possible.
The North American Aerospace Defense Command (NORAD) is a combined Command of
the United States and Canada that provides aerospace warning and protection for North
America. It is pursuing a three-phase plan to improve the defense against cruise missiles for
the United States and Canada. In addition, NORAD and the U.S. Air Force are upgrading
aircraft that monitor the U.S. airspace with new sensors capable of tracking and targeting
challenging offensive air threats like advanced cruise missiles.

Regional and Transregional Missile Defense
Potential adversaries continue to expand the capability and capacity of their regional offensive
missile inventories. The United States will strengthen its efforts to deter and counter them.
The global offensive missile threat environment represents a sea-change in the operationalsetting that U.S. forces will have to navigate in future regional conflicts. The United States
and allies can no longer assume the capacity to concentrate forces in secure, forward locations
and launch military operations against adversaries from these secure locations. Defending
effectively against offensive missile threats will help deter adversaries, assure allies andpartners, preserve U.S. and allied freedom of action, limit the potential for coercive adversary
missile threats, and reduce the effects of potential adversary regional missile strikes.
Strengthening U.S. regional defenses in this environment is not only an active missile defense
challenge. Given the large inventory of adversary regional missiles relative to our more
limited inventory of active defenses, the United States will leverage investments in platforms,
weapons, and military expertise to develop complementary attack operations. U.S.
Combatant Commanders will plan and conduct active missile defense and attack operations as
an overall joint campaign employing the full range of U.S. capabilities. In addition, the UnitedStates will seek to integrate U.S., allied, and partner capabilities for active missile defense and,as appropriate, attack operations capable of striking the entire range of infrastructure
supporting adversary offensive missile operations.
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Regional Active Defenses
The United States continues to make significant progress in the development, deployment,
and modernization of regional active missile defense capabilities. DoD currently fields a
number of regional active defense systems to intercept potential adversary regional offensive
missiles, including mobile sensors and interceptors that can be surged to zones of crisis orconflict and, if they are interoperable with allied and partner assets, can support combined
defensive operations. The regional missile defense posture is increasingly flexible andadaptable to meet evolving threats and new classes of offensive missiles as they emerge,
including advanced, extended-range cruise missiles and HGVs.
Terminal High Altitude Area Defense (THAAD): The THAAD system engages short-, medium-,and intermediate-range ballistic missiles using hit-to-kill technologies. At this time, theUnited States possesses seven THAAD batteries, including one in Guam and one in the
Republic of Korea (ROK). DoD is continuing to develop software upgrades for THAAD toprovide advanced capability against emerging threats. These activities will enable theexpansion of both THAAD system interoperability with air and missile defense systems and its
defended area against future threats.
Aegis Sea-based Missile Defense: The Aegis Weapon System for active missile defense provides
protection at sea and ashore against regional ballistic missiles. The United States is testing
improved variants of both the Aegis SM-3 and SM-6 missiles, and fielding a new sensor, tosignificantly increase Aegis missile defense capabilities. Multi-mission Aegis BMD-capable
ships are highly maneuverable and survivable, and will be surged as needed during crisis andconflict. The combination of increased ship numbers and capability will result in a more
flexible and resilient Aegis force with significantly greater missile defense capability.
Aegis Ashore: The Aegis Ashore is the land-based version of the Aegis Weapon System and isoperated by the U.S. Navy as part of the European Phased Adaptive Approach (EPAA). An
Aegis Ashore site in Romania is operational, armed with the SM-3 interceptor, and provides
continuous defense of European NATO territory against Middle East missile threats. It iscurrently operating under NATO command and control. An Aegis Ashore site in Poland isunder construction and will become part of NATO ballistic missile defense upon completion.
These Aegis Ashore sites will soon be equipped with the SM-3 Blk IIA, significantly
strengthening their defense of NATO territory.
Patriot Advanced Capability-3 (PAC-3): The Patriot air and missile defense system has a provencombat record. It can launch several interceptor variants, and is now deployed with U.S.,
allied, and partner forces in multiple theaters to defend against SRBMs and cruise missiles.
Since the initial deployment of Patriot in 1982, the United States has continuously improved
the system.

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Congress provided funding in FY17 and FY18 to procure additional Patriot, THAAD, and SM3 interceptors. These missile procurements are part of an emergency funding request by the
Administration to take immediate measures to protect the U.S. homeland, forces deployedabroad, allies, and partners. They are additive to the current program, and will increase thegrowing inventory of U.S. missile defense interceptors available in a crisis.

Preparing for Emerging Offensive Missile Threats and Uncertainties
DoD is taking steps consistent with the annual budget process to improve or adapt existing
systems, relocate or surge mobile systems, and, build new systems, including some on arelatively short timeline. These steps advance the goals of staying ahead of rogue state
offensive missile threats to the homeland, meeting the diverse range of regional offensive
missile threats, and hedging against future threats. Developing and fielding the means to
defend against emerging HGVs, for example, will be critical to address concern over theerosion of U.S. regional military advantages expressed in the 2018 NDS.
Improve or adapt existing systems. The SM-3 Blk IIA interceptor is intended as part of the regional
missile defense architecture, but also has the potential to provide an important “underlay” toexisting GBIs for added protection against ICBM threats to the U.S homeland. This
interceptor has the potential to offer an additional defensive capability to ease the burden on
the GBI system and provide continuing protection for the U.S. homeland against rogue states’
long-range missile capabilities. The Missile Defense Agency (MDA) will test the SM-3 Blk IIA
against an ICBM-class target in 2020.
Adapting existing capabilities to perform new missions for homeland and regional missile
defense also will be necessary. For example, DoD’s newest tactical aircraft, the F-35
Lightning II, can track and destroy adversary cruise missiles today, and, in the future, can beequipped with a new or modified interceptor capable of shooting down adversary ballistic
missiles in their boost phase. Another repurposing option is to operationalize, either
temporarily or permanently, the Aegis Ashore Missile Defense Test Center in Kauai, Hawaii,
to strengthen the defense of Hawaii against possible North Korean missile attack.
The Multi-Object Kill Vehicle (MOKV) is a next generation kinetic kill vehicle for the GBI
designed to improve the ability to engage ICBM warheads, decoys, and countermeasures using
a single defensive interceptor. While the number of GBIs is limited, MOKV could improve
the performance of the GMD system by increasing the probability of successfully intercepting
the warhead.
Relocating/surging mobile systems. DoD will surge missile defense capabilities promptly in acrisis or conflict, as needed, and ensure that doing so is featured in operational planning. For
example, Patriot and THAAD systems, and multi-mission Aegis BMD-capable ships armed
with the SM-3 Blk IIA interceptor will be moved into position quickly in a crisis to strengthen
the defense of the homeland against rogue state missile threats. In the future, additional missile
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defense capabilities, such as the F-35 and boost-phase defenses could also contribute to U.S.
mobile capabilities to be surged as necessary in crisis or conflict.
Building new systems. The United States may decide to increase further the capacity of the GMD
force beyond the currently planned force size of 64 GBIs. The missile base in Ft. Greely,
Alaska, has the potential for up to an additional 40 interceptors. In addition, building a new
GBI interceptor site in the continental United States would add interceptor capability against
the potential expansion of missile threats to the homeland, including a future Iranian ICBM
capability. The decision to do so, and site selection, will be informed by pertinent factors at
the time, particularly emerging threat conditions.
Intercepting offensive missiles in their boost-phase would increase the likelihood of
successfully countering missile threats, complicate an aggressor’s attack calculus by reducing
its confidence in its missile attack planning, and reduce the number of midcourse or terminal
active defense interceptors needed to destroy the adversary’s remaining offensive missiles.
Developing scalable, efficient, and compact high energy laser technology holds the potential
to provide a future cost-effective capability to destroy boosting missiles in the early part of the
trajectory. Doing so would leverage earlier technological advances, including for example
advances in beam propagation and beam control. DoD is developing a Low-Power Laser
Demonstrator to evaluate the technologies necessary for mounting a laser on an unmanned
airborne platform to track and destroy missiles in their boost-phase.
Space-basing for sensors provides significant advantages. Such sensors take advantage of thelarge area viewable from space for improved tracking and potentially targeting of advanced
threats, including HGVs and hypersonic cruise missiles.
The space-basing of interceptors also may provide significant advantages, particularly forboost-phase defense. As directed by Congress, DoD will identify the most promisingtechnologies, and estimated schedule, cost, and personnel requirements for a possible spacebased defensive layer that achieves an early operational capability for boost-phase defense.

Attack Operations for Missile Defense
If deterrence fails and conflict with a rogue state or within a region ensues, U.S. attack
operations supporting missile defense will degrade, disrupt, or destroy an adversary’s missiles
before they are launched. Such operations are part of a comprehensive missile defense strategy
and increase the effectiveness of active missile defenses by reducing the number of adversary
missiles to be intercepted. DoD will invest in the capabilities necessary for attack operations,such as improved attack warning intelligence, ISR, time-sensitive targeting, as well as the longrange precision and air-, land-, and sea-strike capabilities necessary for destroying mobile
missiles prior to their launch.

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V. Missile Defense Management and Testing
In 2002, DoD directed MDA to use flexible acquisition approaches to develop capabilities
quickly and directed the Services to field missile defense elements as soon as practicable. Thisdecision to pursue missile defense systems on an accelerated timeline enabled the United States
to field an initial operational homeland missile defense system by the fall of 2004, prior to
North Korea’s Taepodong-2 ICBM/SLV test in 2006.
Given the worsening missile threat environment, DoD must prioritize speed of delivery,
continuous adaptation, and deliver enhanced performance at the speed of relevance. To doso, DoD must adopt processes and cultures that enable MDA and the Services to streamline
and refine acquisition processes, ensure flexibility in the development, testing, and fielding of
missile defense, and swiftly adapt systems once fielded. Services and Combatant Commanders
should be involved early in the missile defense capability development process to identify
needed system performance requirements and to establish the conditions and timeline fortransferring the program from MDA to a Service. In addition, as transregional missile threats
increase, missile defense planning will be global in nature and coordinated across geographic
combatant commands.
DoD and MDA will pursue a rigorous test program that enables us to counter evolving
offensive missile threats, to include increasing the frequency of test events given the speed ofadversary innovation. Ground and flight tests provide data needed for highly advanced
modeling and simulation activities that allows DoD to measure and predict the performanceof all missile defense technologies. They provide learning opportunities to characterize andpotentially optimize the performance of each element. Even tests that are not fully successful
may be useful by providing valuable information to assess the performance of the system. We
must not fear test failure, but learn from it and rapidly adjust.

VI. Working with Allies and Partners
The 2017 NSS emphasizes that strengthening our alliances and long-term security partnerships
is a top U.S. priority. As offensive missile capabilities continue to proliferate, missile defense
cooperation with allies and partners has gained increasing importance to advance missile
defense architectures for our common protection, deterrence and assurance. This cooperation
will leverage our joint contributions and focus on expanding opportunities for collaboration
on missile defense programs; deepening interoperability in missile defense systems andoperations; expanding burden sharing among the United States and its allies and partners; andlimiting the proliferation of advanced offensive missile technologies and components.

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The United States will pursue enhanced missile defense cooperation with allies and partners,
place a renewed emphasis on interoperability, and seek to integrate capabilities as appropriate.
Successfully operating in today’s complex missile threat environment demands that we detectlaunches as soon as possible, track them, and intercept them as early in flight as feasible. Thisrequires interoperability among various missile defense capabilities to include command andcontrol networks, sensors, and Integrated Air and Missile Defense (IAMD) systems. Moving
towards networks of interoperable IAMD systems can take advantage of cost-sharing and help
distribute the burden of common defense to better address adversary A2/AD strategies.
For our common defense, DoD will encourage allies and partners to invest in their own air
and missile defense capabilities that are interoperable with U.S. capabilities. DoD will alsoprioritize requests for U.S. military equipment sales, accelerating foreign partner
modernization and the ability to integrate with U.S. forces. The United States has alreadytaken steps to streamline procedures for our allies and partners to acquire U.S. defense
capabilities.

Indo-Pacific
The cornerstone of our security and diplomacy in the Indo-Pacific region is our strong bilateralalliances with Japan, South Korea, and Australia, and emerging security relationships withothers such as India. Japan and South Korea are each working with the United States to build
missile defense systems that are increasingly interoperable with U.S. defenses and increasingly
capable against regional offensive missile threats and coercion. This cooperation includes
bilateral missile defense training exercises with the United States. Australia participates in atrilateral discussion on missile defense with the United States and Japan. The United Statesand Australia meet annually to discuss bilateral missile defense cooperation. New areas offocus include joint examination of the challenges posed by advanced missile threats.

Europe and NATO
Missile defense plays a critical role in the NATO Alliance’s defense of Europe from coercion
and aggression. Interoperable NATO active missile defense systems will improve theAlliance’s collective defense capabilities. The United States is committed to completing the
deployment of EPAA, which is the U.S. contribution to NATO ballistic missile defense andwill expand defensive coverage against medium- and intermediate-range ballistic missile
threats from the Middle East.
In addition to these EPAA capabilities against medium- and intermediate-range threats,
individual NATO Allies are also fielding national air and missile defense systems designed todefend against shorter-range ballistic and cruise missiles. These allied active defenses will playa crucial role in countering missile strikes that underpin potential adversaries’ A2/ADXVIMISSILE DEFENSE REVIEW

operations. The Alliance is also making progress towards enhanced missile defense
interoperability among national systems and integration of missile warning to support
combined missile defense operations. A “deepening of interoperability” will enable theAlliance’s forces to act together more coherently and effectively to counter missile strikes.

The Middle East – Gulf Cooperation Council
The United States is working closely with Gulf Cooperation Council (GCC) partners toencourage them to acquire and deploy missile defense capabilities that, when integrated overtime, would provide the basis for a networked, layered defense across the region. U.S.
Central Command maintains a series of regular engagements with GCC air and missile defense
forces. These important exchanges are establishing the foundation for joint missile defense
planning and operational cooperation.

The Middle East – Israel
The United States will sustain its strong missile defense partnership with Israel, underpinned
by a new U.S.-Israel Memorandum of Understanding (MOU) that includes a commitment of$500 million for Israeli missile defense each year beginning in Fiscal Year (FY) 2019 throughFY 2028. Under this MOU, DoD will sustain extensive cooperation with Israel, and seek
increased opportunities to take advantage of Israeli research and development efforts for
similar U.S. defense missions.

South Asia
A number of states in South Asia are developing an advanced and diverse range of ballistic
and cruise missile capabilities. Within this context, the United States has discussed potential
missile defense cooperation with India. This is a natural outgrowth of India’s status as a
Major Defense Partner and key element of our Indo-Pacific Strategy.

North America
Since NORAD’s establishment in 1958, significant progress has been made toward countering
evolving air and missile threats to the United States and Canada. NORAD routinely maintains
forces on alert for homeland air defense, including cruise missile defense. The United States
will continue to work with Canada to modernize NORAD’s ability to counter cruise missile
threats and detect, track, warn and defend against advanced missile threats. The United States
and Canada are conducting a joint examination of options to renew or replace the North
Warning System, a bilateral integrated network, and adapt this capability to new threats.

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VII. Conclusion
For the past 17 years, the United States has devoted significant effort to developing anddeploying a layered missile defense system. These efforts have enabled the continued
improvement in U.S., allied, and partner missile defense performance and affordability. Withfurther planned investments, these improvements will continue well into the future.
This 2019 MDR establishes a policy framework for U.S. missile defense that is responsive to
new threats and exploits new approaches to the defensive mission. It adopts a balanced andintegrated approach to countering missile threats through a combination of deterrence, active
and passive missile defenses, and attack operations. This framework emphasizes the priority ofprotection for the American homeland against emerging and future rogue states' missile
threats, in addition to robust regional missile defense for U.S. forces abroad, allies, andpartners against all potential adversaries.
Moving forward, the United States, allies, and partners will pursue a comprehensive missile
defense strategy that will deliver integrated and effective capabilities to counter ballistic,
cruise, and hypersonic missile threats. Doing so will sustain and strengthen our capabilities toprotect the homeland, deter adversaries, protect and assure allies and partners, and hedge
against future threats in all domains. It will also help enable the United States to project power
into contested environments in support of allies and partners and provide U.S. leaders with aposition of strength in their diplomatic engagements to reduce tensions and limit security
challenges.
The U.S. BMDS must be continuously strengthened and expanded given the growing
challenges posed by potential adversaries, particularly rogue states, who are contesting theestablished international order and deploying greater numbers of increasingly sophisticatedoffensive missiles. The men and women of the Defense Department and our Armed Forces
stand ready to meet this challenge, both today and in the future.

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