For more information on the European system, see European Phased Adaptive Approach (EPAA) at a Glanceand for the Asia-Pacific Region, see U.S. and Allied Ballistic Missile Defenses in the Asia-Pacific Region.
Contact: Kingston Reif, director for disarmament and threat reduction policy, 202-463-8270 x104
- Executive Summary
- Elements of the Current U.S. Ballistic Missile Defense System
- Ground-based Midcourse Defense
- Aegis Ballistic Missile Defense
- Terminal High Altitude Area Defense(THAAD)
- Patriot Advanced Capability (PAC-3)
- Space-based Infrared System-High (SBIRS-HIGH)
- The 2019 Missile Defense Review To-Do List
- Next Generation Efforts
- Congressional Proposals
According to Missile Defense Agency (MDA) estimates, Congress has appropriated over$200 billion for the agency’s programs between fiscal years 1985 and 2019. That total does not include spending by the military services on programs such as the Patriot system or the many additional tens of billions of dollars spent since work on anti-missile systems first began in the 1950s.
For nearly two decades, U.S. ballistic missile defense (BMD) policy has sought to protect the homeland against limited long-range missile strikes from states such as Iran and North Korea, but not major nuclear powers like Russia and China asthat mission would pose significant technical, financial, and geopolitical challenges. The United States has also pursued programs to defend U.S. troops and facilities abroad, as well as some close allies, from attacks by ballistic missiles—and to a much lesser extent cruise missiles.
The overall U.S. missile defense effort enjoys strong bipartisan support in Congress. Additionally, many U.S. allies place a high value on missile defense cooperation with the United States.
However, the U.S. pursuit of effective missile defenses has been accompanied by intense debate about the technical capabilities of the system and realism of testing, the scope of the ballistic missile threat, the deterrence and assurance benefits of defenses, the cost-effectiveness of shooting down relatively inexpensive offensive missiles with expensive defensive ones, and the repercussions for U.S. strategic stability with Russia and China.
According tothe Defense Department’s independent testing office, existing U.S. missile defenses have "demonstrated capability" to defend the U.S. homeland against a small number of intercontinental ballistic missile (ICBM) threats that employ "simple countermeasures." The testing office assesses that defenses to protect allies and U.S. troops deployed abroad possess only a “limited capability” to defend against small numbers of intermediate-range ballistic missiles (IRBMs) and medium-range ballistic missiles (MRBMs). The capability of defenses against short-range ballistic missiles is labeled as “fair.” Apart from the point-defense Patriot system, no systems in the U.S. BMD arsenal have been used in combat.
Leaders of the U.S. missile defense enterprise have increasingly voiced concerns that the current U.S. approach to national and regional missile defense is unsustainable and that existing defenses must be augmented with emerging capabilities to reduce the cost of missile defense and keep pace with advancing adversary missile threats.
The Trump Administration
In May 2017, pursuant to direction from President Donald Trump and Congress, then Defense Secretary James Mattis formally announced the beginning of the department’s Ballistic Missile Defense Review, which is taking a wide-ranging look at missile defense policy and strategy. The review was finally released in February 2019, one year after its original completion target.
Broadly, the review proposes to expand the role and scope of U.S. missile defenses by focusing not only on ballistic missiles, but also other types of missile threats, such as regional cruise and hypersonic missiles. It also proposes placing greater emphasis on the importance of space and new technologies to intercept missiles during their boost phase when they are traveling at their slowest. The review also calls for integrating offensive attack operations more closely with missile defenses and to supplement the defense of the U.S. homeland with the Aegis Standard Missile-3 (SM-3) Block IIA interceptor.
The review also re-affirmed previously announced plans by the Trump administration to arm unarmed aerial vehicles with lasers to zap long-range missiles during their boost phase, expand the Ground-Based Midcourse Defense (GMD) system from 44 to 64 interceptors by 2023 (though this plan has since been indefinitely delayed), focus on “left of launch” capabilities to destroy a missile threat before it launches, and field a space-sensor layer to provide birth-to-death tracking of ballistic missiles and hypersonic glide vehicles. The review also called for 11 follow-up studies, which are detailed in the below section, The 2019 Missile Defense Review To-Do List.
Since President Trump’s inauguration, the administration has vowed to expand national and regional missile defense systems of every kind, and Congress has supported these efforts. In fiscal year 2018, Congress approved $11.5 billion for the Missile Defense Agency, an increase of $3.6 billion, or 46 percent, from the Trump administration’s May 2017 initial budget request. The appropriation is the largest Congress has ever provided for the agency after adjusting for inflation.
Congress approved another big increase for fiscal year 2019, approving $10.3 billion for the agency, an increase of $1.4 billion above the budget request of $9.9 billion.
Notably, the fiscal year 2020 request seeks $380 million over the next five years to develop and test by 2023 a prototype space-based laser weapon to destroy ICBMs during their boost and midcourse phases of flight.
For ballistic missile and missile defense basics, as well as the historical background of missile defense programs, please visit “Missiles and Missile Defense Systems at a Glance.”
Elements of the Current U.S. Ballistic Missile Defense System
The following charts provides a brief look at some of the major missile defense programs maintained by the United States. It contains information on what type of ballistic missile each defense would be intended to counter and at which stage of the enemy missile’s flight an attempted intercept would take place. Also included are the Pentagon’s estimates on when each defense may have an initial, rudimentary capability, as well as when it could be fully operational. For basics about missiles, missile defense systems and their various components, or the general history of the U.S. missile defense system and recently cancelled programs, visit the “Missile Defense Systems at a Glance” fact sheet.
GROUND-BASED MIDCOURSE DEFENSE | |
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AEGIS BALLISTIC MISSILE DEFENSE (BMD) | |
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Capability / Schedule |
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TERMINAL HIGH ALTITUDE AREA DEFENSE (THAAD) | |
Program & Key Elements |
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PATRIOT ADVANCED CAPABILITY-3 (PAC-3) | |
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The following is an overview of the U.S. early warning system that complements the missile defense systems listed above.
SPACE-BASED INFRARED SYSTEM-HIGH (SBIRS-HIGH) | |
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Dates Operational |
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Cost |
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Major Issues |
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The 2019 Missile Defense Review To-Do List
The 2019 Missile Defense Review identified 11 issues that needed “follow-up” analysis to make a policy direction determination, which were scheduled to be completed within six months after the January 2019 review release date.
Homeland Cruise Missile Defense | Designating a service or defense agency with acquisition authority—by using the existing requirements-generation process—to find ways to defend the homeland against offensive cruise missiles. |
Worldwide THAAD Number Requirements | The Army, the Joint Chiefs of Staff, and MDA will prepare a report that assesses the number of THAAD battery requirements needed to support worldwide deployments. |
Aegis Destroyers Fully-BMD Capable Timeline | The Navy and MDA must deliver a report on how the entire fleet of Aegis destroyers can be converted to become fully capable against incoming missiles, including ballistic missiles, within 10 years. |
Homeland Missile Tracking and Discrimination | MDA and Northern Command must prepare a plan to “accelerate efforts to enhance missile defense tracking and discrimination sensors, to include addressing advanced missile threats,” particularly focused on the homeland. |
F-35 Missile Defense | The Air Force and MDA are on the hook for a joint report on how best to integrate the F-35 Joint Strike Fighter, including its sensor suite, into America’s missile defense networks for both regional and homeland defense. The MDR posits that the F-35 could eventually be used to take out ballistic missiles during their boost phase, which experts have said is unlikely to be technically feasible. |
Aegis Ashore Test Center in Hawaii | The Department of Defense is looking at the potential to operationalize the Aegis Ashore Missile Defense Test Center location in Hawaii into a full-up missile defense site to counter potential missile launches from North Korea. MDA and the Navy will evaluate the option and develop a plan that could operationalize the location within 30 days, if needed. |
Study on Space-based Intercept Layer | MDA will study development and fielding of a space-based missile intercept layer capable of boost-phase defense, including the most promising technologies, estimated schedules, cost, and personnel requirements. |
More Efficient Acquisition and Development | A big point of emphasis from officials talking about the MDR is that they believe the acquisition and development of new technologies can and will go faster. To that end, the review calls for reviews of the current Warfighter Involvement Process, which determines missile defense requirements, in order to make sure commanders who will use the systems are involved early in the process of developing the systems and requirements. |
Transregional Defense Integration | While the Pentagon divides the world into regional areas of responsibility, the nations capable of threatening American assets or allies with missiles do not necessarily. The chairman of the Joint Chiefs and the head of U.S. Strategic Command are therefore ordered to come up with a plan for “optimal roles, responsibilities, and authorities for achieving greater transregional missile defense integration.” |
Left of Launch | Another requirement from the 2017 National Defense Authorization Act is for the designation of an office with acquisition authority specific to pre-launch attack operations—that is, someone who leads procurement of new technologies designed to destroy an enemy missile before it can take off. That agency must be identified within six months; after that happens, a larger review will begin to examine roles and responsibilities for updating operational doctrine in terms of left-of-launch strikes. |
Hypersonic and Cruise Missile Homeland Warning | And for a change of pace, the Pentagon will have nine months to research improvements for timely warnings on hypersonic and advanced cruise missiles launched at the U.S. homeland. At the completion of the study, the Office of Cost Assessment and Program Evaluation will initiate an analysis of alternatives for materiel solutions to provide early warning and attack assessment against these advanced threats and their integration into the nuclear command-and-control architecture. |
The Missile Defense Agency is focusing its newest efforts to ensure the system stays ahead of developing foreign missile threats (see the below chart). Some of the advanced anti-missile technologies the Defense Department is pursuing, such as airborne lasers to zap missiles in the early stages of their flight, have been unsuccessfully pursued in the past.
Multi-Object Kill Vehicle | Three defense contractors (Boeing, Lockheed Martin, and Raytheon) have been awarded contracts to develop concepts to deploy multiple kill vehicles from one booster in order to destroy decoys and multiple warheads ejected from ICBMs. MDA had planned to begin fielding that kill vehicle in 2025, but the future of this effort is uncertain. |
Boost Phase Laser Defenses | MDA is recommitting to research to determine how to develop laser beams that could destroy missiles in their boost phase. Inspired by the ABL program, the vision for the new system is to mate a powerful solid-state laser to drones. MDA aims to develop a laser demonstrator by 2020 or 2021 and a deployed capability by 2025. The MDR also called for a review of developing a new weapon for the F-35 fighter jet which could intercept an intercontinental ballistic missile its in boost-phase. |
Left of Launch | Left of launch is a proposed strategy that would be designed to counter missile threats before the missile is launched so as to reduce the need for expensive anti-missile interceptors to attempt to shoot down the missile. Tactically, the strategy would likely include the of cyber-attacks and electronic warfare to achieve this goal. Despite much speculation in the press about the U.S. ability to hack North Korean missile tests, the data shows that North Korea’s missile tests are succeeding at a high rate and that the failures are concentrated in new systems that had not been previously tested. The 2019 MDR reaffirmed the Trump administration’s plans to continue with this strategy |
Space-Based Sensor Layer | In August 2018, then MDA Director Samuel Greaves described what the agency envisages for a future more comprehensive space sensor layer. Such a layer could look like the Air Force’s Overhead Persistent Infrared Global Scanning system and could have a regional detection and tracking capability staring down at Earth that could go after targets that are currently harder to detect or in low earth orbit, such as hypersonic missiles, and could catch missiles in the boost or burnout phases of flight. The sensor could also cover the midcourse portion of a missile’s flight by looking against the background of space and discriminate, track, and eventually send data directly to the ballistic missile defense weapon system for fire control. Finally, the sensor could also record towards the end of a missile’s trajectory whether an intercept against a target occurred or was missed. |
Space-Based Interceptor Layer | According to the 2019 MDR, “Given the significant advantages of space-basing for sensors, and potentially interceptors, particularly for boost-phase defense, MDA will study development and fielding of a space-based missile intercept layer capable of boost-phase defense and provide a report to USDR&E, and USDP within six months after the release of the MDR.” The fiscal year 2020 White House budget requested $15 million for the new Space Development Agency to “develop a government reference architecture for a space-based kinetic interceptor layer for boost-phase defense.” It also requested $34 million for the 2020 fiscal year to develop and test by 2023 a prototype space-based directed-energy (laser) weapon for ICBMs during their boost phase. Over the course of five years, the program is expected to cost $380 million. |
In recent years, Congress has sought to encourage the expansion ofthe U.S. ballistic missile defense effort in the face of advancing adversary ballistic missile capabilities. These initiatives, which are summarized below, have been met with strong resistance from the administration.
A Third National Missile Defense Site on the U.S. East Coast | In the fiscal year 2013 National Defense Authorization Act, Congress required the Defense Department to conduct a study to evaluate at least three possible new long-range interceptor sites that could augment the GMD system, including at least two on the East Coast. The Defense Department announced in May 2016 that it completed a draft study of three possible locations in the eastern United States for a new ballistic missile defense interceptor site, but said it had no plans to actually build such a site. The three sites are: Ft. Drum, New York; Camp Ravenna, Ohio; or Ft. Custer, Michigan. The draft environmental impact statement, which was posted on the MDA website May 31, 2016, said that the Defense Department “does not propose and has not made a decision to deploy or construct an additional interceptor site.” The Trump administration missile defense review noted the benefits of a new third GBI interceptor site in the eastern United States and noted that the Defense Department has already prepared an Environmental Impact Statement evaluating locations. Though the administration declined to name a third missile defense site on the East Coast in that review, on June 26 the Defense Department sent a letter to Rep. Eliste Stephanik (R-N.Y.) announcing that Fort Drum, in her district, was selected as the third missile defense site, but that there was “no intent to develop one” because of a study earlier this year noting its cost due to environmental challenges. |
Revising the 1999 National Missile Defense Act | The FY 2017 National Defense Authorization Act revised the 1999 National Missile Defense Act to remove the world “limited,” and the 2018 NDAA authorized expansions in the national missile defense program. Proponents of the change argue that the 1999 legislation has prevented the Defense Department from adequately planning for the protection of the U.S. homeland from the full spectrum of ballistic missiles threats, including threats posed by Russia and China. The Obama administration strongly objected to the change, stating that the word “limited” is specifically intended to convey that the U.S. homeland missile defense system is designed and deployed to counter limited attacks (in number and sophistication) from Iran and North Korea, and not to counter the strategic deterrence forces of Russia and China. |