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U.S. Missile Defense Programs at a Glance
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For more information on the European system, see European Phased Adaptive Approach (EPAA) at a Glance.

Updated: September 2017

Contact: Kingston Reif, director for disarmament and threat reduction policy, 202-463-8270 x104

Executive Summary

Two Terminal High Altitude Area Defense (THAAD) interceptors are launched during a successful intercept test. (Photo: US Missile Defense Agency Flickr)

According to Missile Defense Agency (MDA) estimates, Congress has appropriated roughly $190 billion for the agency’s programs between fiscal years 1985 and 2017. 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 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 Russia and China, as that mission would pose significant technical, finanacial, and geopolitical challenges. The United States has also pursued programs to defend U.S. troops and facilities abroad, and 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, the scope of the ballistic missile threat, the deterrence and assurances benefits of defenses, the cost-effectiveness of shooting down relatively inexpensive offensive missiles with expensive defensive ones, and the impact on strategic stability of U.S. defenses with Russia and China.

According to the 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 simple, intercontinental ballistic missile (ICBM) threats that employ "simple countermeasures." The testing office assesses that defenses to protect U.S. troops deployed abroad and allies 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 ranks a bit better at “fair.” Apart from the point-defense Patriot system, no systems in the current U.S. arsenal of ballistic missile defenses 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.

Ballistic missile defense ranked high among the priorities of the George W. Bush administration, which withdrew the United States from the 1972 Anti-Ballistic Missile (ABM) Treaty in 2002 so that it could attempt to implement the charge in the National Missile Defense Act and develop and deploy a nationwide defense against a limited number of long-range ballistic missiles. The United States attempted to implement long-range ballistic missile defense only once before over the last 50 years. The first effort, Safeguard, was shut down within a few months of being declared operational in October 1975 because Congress concluded it was too expensive and ineffectual. Safeguard was allowed under the ABM Treaty since it was limited to no more than 100 interceptors protecting an intercontinental ballistic missile (ICBM) base in North Dakota.

Upon taking office in 2009, the Obama administration took steps to curtail the Bush administration’s rush to expand the U.S. homeland missile defense footprint and instead place greater emphasis on regional defense, particularly in Europe. The Obama administration decided to alter its predecessors plans for missile defense in Europe, announcing on Sept. 17, 2009, that the United States would adopt a “Phased Adaptive Approach” to missile defense on that continent. This approach primarily uses the currently sea-based Aegis Ballistic Missile Defense system to address the threat posed by short- and intermediate-range ballistic missiles from Iran. The Aegis system’s Standard Missile-3 (SM-3) has been placed on land in Romania and will similarly be placed in Poland.

President Obama's first Secretary of Defense, Robert Gates, also canceled a number of next generation programs, including two designed to intercept missiles during their boost phase, due to "escalating costs, operational problems, and technical challenges."

However, while continuing to invest in regional defense, the Obama administration took its foot off the homeland defense brake in its second term, in large part in response to North Korea.

The Defense Department announced in March 2013 that it would augment the ground-based midcourse defense (GMD) system in Alaska and California, which is designed to protect the United States against limited, long-range missile strikes from North Korea and Iran, by increasing the number of interceptors from 30 to 44 by the end of 2017. The administration took this step despite concerns about the technical viablity of the system.

The administration also oversaw the deployment of additional regional missile interceptor and sensor capabilities to allies in Northeast Asia in response to North Korea, including the deployment of the terminal high altitude area defense (THAAD) system to Guam and South Korea and two advanced radars to Japan.

In May 2017, pursuant to direction from President Donald Trump and Congress, Defense Secretary James Mattis formally announced the beginning of the department’s Ballistic Missile Defense Review, which will take a wide-ranging look at missile defense policy and strategy. The review is scheduled to be completed by the end of the year.

The president has provided few details about his vision for missile defense systems. A brief reference on the defense issues page of the White House website states, “We will … develop a state-of-the-art missile defense system to protect against missile-based attacks from states like Iran and North Korea.”

Ballistic Missile Basics

Ballistic missiles are powered by rockets initially but then follow an unpowered, parabolic trajectory toward their target. They are classified by the maximum distance that they can travel, which is a function of how powerful the missile’s engines (rockets) are and the weight of the missile’s warhead. To add more distance to a missile’s range, rockets are stacked on top of each other in a configuration referred to as staging.

Four classifications of ballistic missiles:

  • Short-range ballistic missiles, traveling less than 1,000 kilometers (approximately 620 miles)
  • Medium-range ballistic missiles, traveling between 1,000–3,000 kilometers (approximately 620-1,860 miles)
  • Intermediate-range ballistic missiles, traveling between 3,000–5,500 kilometers (approximately 1,860-3,410 miles)
  • Intercontinental ballistic missiles (ICBMs), traveling more than 5,500 kilometers (approximately 3,410 miles)

Short- and medium-range ballistic missiles are referred to as “theater” ballistic missiles, whereas ICBMs or long-range ballistic missiles are described as “strategic” ballistic missiles. The ABM Treaty had prohibited the development of large-scale, nationwide strategic defenses, but permitted development of theater missile defenses, as well as single-site strategic defenses.

Three stages of flight:

Boost Phase:

  • Begins at launch and lasts until the rocket engines stop firing and pushing the missile away from Earth.
  • Depending on the missile, lasts between three and five minutes.
  • Generally the missile is traveling relatively slowly, although toward the end of this stage an ICBM can reach speeds of more than 24,000 kilometers per hour. Most of this phase takes place in the atmosphere (endoatmospheric).

Midcourse Phase:

  • Begins after the rockets finish firing and the missile is on a ballistic course toward its target.
  • Longest stage of a missile’s flight, lasting up to 20 minutes for ICBMs.
  • During the early part of the midcourse stage, the missile is still ascending toward its apogee, while during the latter part it is descending toward Earth.
  • During this stage the missile’s warhead(s), as well as any decoys, separate from the delivery platform, or "bus." This phase takes place in space (exoatmospheric).

Terminal phase:

  • Begins when the missile’s warhead re-enters the Earth’s atmosphere (endoatmospheric), and it continues until impact or detonation.
  • This stage takes less than a minute for a strategic warhead, which can be traveling at speeds greater than 3,200 kilometers per hour.

Elements of the 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 Pentagon estimates on when each defense may have an initial, rudimentary capability as well as when it could be fully operational.


Program & Key Elements

  • Key element: ground-based missile interceptor consisting of a multistage booster and an exoatmospheric kill vehicle (EKV).
  • EKV separates from the booster in space and seeks out its target through radar updates and use of its onboard visual and infrared sensors.
  • The EKV destroys its target by colliding with it. This process is referred to as "hit-to-kill" or "kinetic kill."

Designed to Counter

  • Goal: intercept strategic ballistic missile warheads in midcourse stage.


  • Initially fielded in 2004
  • Over $40 billion has been spent on the GMD system to date.
  • MDA claims that the system has had ten successful intercepts in 18 tests. Only two of the past four intecept tests since 2008 has been successful.
  • The first test of the GMD system against an ICBM-class target took place on May 30, 2017 and was deemed successful.
  • The next test of the GMD system is scheduled for late 2018 and, for the first time, will involve firing two interceptors against one ICBM target. In a real-world scenario, multiple interceptors would be fired at an incoming missile.

Capability / Schedule

  • In March 2013, the Pentagon announced plans to field a total of 44 interceptors at Fort Greely by 2017. The Pentagon currently deploys 36 interceptors – 32 at Fort Greely, Alaska, and four at Vandenberg Air Force Base, California. 20 of the 32 interceptors deployed in Alaksa are armed with an older kill vehicle that has not had a successful flight intercept test since 2008. The final eight interceptors will be armed with an upgraded version of the existing GMD kill vehicles knowns as the CE-II Block I.
  • The interceptors are supported by land- and sea-based radars. Early Warning Radar are being upgraded to support the system. Upgrades have been carried out at Beale Air Force Base, California and at Fylingdales, UK. Upgrade work is also underway at Thule Air Force Base, Greenland and is scheduled to take place at Clear, Alaska. The less powerful, west-facing, COBRA Dane radar on Shemya Island, the Aleutian Islands also completed an upgrade in February 2010.
  • Former MDA Director Adm. James Syring told a Senate panel in 2013 that the MDA tests the GMD system “in a controlled, scripted environment based on the amount of time and money each one of these tests costs.” This means the there are limits to the realism of the test scenarios.
  • The GMD system has not been tested against complex decoys and countermeasures that North Korea could develop. The system also has not been tested against more than one target at the same time.
  • MDA is investing in the Redesigned Kill Vehicle (RKV), which is intended to enhance the performance of the current EKV, which have been plagued by reliablity problems. The RKV is expected to be deployed in 2022.
  • In October 2015, MDA awarded Lockheed Martin a $784 million contract to develop, deploy, test, and operate the Long Range Discrimination Radar (LRDR). The LRDR is designed to “provide precision metric data to improve ballistic defense discrimination.” According to Lockheed Martin, the LRDR “combines proven solid-state radar technologies with proven ballistic missile defense algorithms.”
  • Following the May 30, 2017, test, the Pentagon's testing office updated its assessement, which had described the GMD system as having only "a limited capability" to defend the U.S. homeland from a small number of simple long-range missiles launched from North Korea or Iran. In a June 6 memo, the office said that the system has "demonstrated capability" to defend against a small number of long-range missiles threats that employ "simple countermeasures."
  • In February and April 2016, the Government Accountability Office (GAO) assessed that MDA has not “demonstrated through flight testing that it can defend the U.S. homeland against the current missile defense threat.” GAO also said that MDA is relying on “a highly optimistic, aggressive schedule” to upgrade the system “which has resulted in MDA: (1) accepting a proven risk of undue concurrency; (2) compromising interceptor reliability and extending risk to the warfighter; and (3) risking the efficacy of its planned flight tests in order to maintain schedule-driven deadlines necessary to meet its 2017 fielding deadline.” A May 2017 GAO report raised several red flags about the RKV program. For example, both U.S. Northern Command and U.S. Strategic Command are questioning whether the seeker planned for the kill vehicle will be able "to detect and track threats in an ICBM-range environment."



Program & Key Elements

  • The Navy’s component of the missile defense system and central to the defense footprint in Asia and the Phased Adaptive Approach to missile defense in Europe. A sea-based system, with missile launchers and radars mounted on cruisers and destroyers. Adaptable to land systems.
  • Key elements of the sea-based defense system: ship-based missile (Standard Missile- 3, or SM-3) and the Aegis combat system.
  • The SM-3 is a hit-to-kill missile comprised of a three-stage booster with a kill vehicle. There are three variations of the SM-3 missile: Block IA, Block IB, and Block IIA. Each variation will be deployed in different phases.

Designed to Counter

  • Geared toward defending against short-, medium-, and intermediate-range ballistic missiles during their midcourse phase with an emphasis on the ascent stage.


  • In 2005 the role of Aegis missile defense evolved from that of a forward sensor to include engagement capability.
  • MDA claims that the SM-3 has a test record of 33 intercepts in 40 attempts which were carried out in 37 flight tests (some of the tests were double tests.) The most recent test was conducted on Dec. 9, 2015, and was declared a success.
  • Japan’s KONGO Class Destroyers have been upgraded with BMD capabilities. Japan and the United States are co-developing the SM-3 block IIA.

Capability / Schedule

  • As of January 2015, there are 33 Aegis BMD ships – 5 cruisers, 28 destroyers.
  • Of the 33 ships, 16 are assigned to the Pacific Fleet and 17 to the Atlantic Fleet.
  • A land based SM-3 block IB deployments occurred in Romania in 2016, the same year ground was broken in Poland on a site to house land based SM-3 IIAs by 2018.
  • The first intercept test of the new SM-3 IIA interceptor occured in February 2017 and was successful. However, the second intercept test of the system in June 2017 failed to destroy the target.


Program & Key Elements

  • Main components: missile comprised of a single rocket booster with a separating kill-vehicle that seeks out its target with the help of a THAAD radar.
  • The THAAD kill vehicle is hit-to-kill.
  • THADD batteries have four components: launcher, interceptors, radar, and fire control. Each battery can carry 48-72 interceptors (there are eight interceptors per launcher and typically each battery is believed to contain six to nine launch vehicles).
  • THAAD missiles are fired from a truck-mounted launcher.

Designed to Counter

  • THAAD’s mission is to intercept short- and medium-range ballistic missiles at the end of their midcourse stage and in the terminal stage.
  • Intercepts could take place inside or outside the atmosphere.


  • THAAD has been tested successfully 15 times since 2006. Four other THAAD tests have been classed as “no-tests.” (Note: A “no-test” occurs when the target malfunctions after launch so the interceptor is not launched.)
  • On July 11, 2017, the U.S. Missile Defense Agency executed a successful intercept test of the THAAD system against an air-launched intermediate-range ballistic missile (IRBM) target. The test was the 14th successful intercept out of 14 attempts for the THAAD missile defense system, and the first test against an IRBM. 

Capability / Schedule

  • The first five THAAD batteries have been made available to the Army for use. MDA plans to produce seven batteries, seven radars, and 539 interceptors.
  • Production of the first interceptors began in March 2011. As the end of FY 2015, 101 of the 539 interceptors had been delivered.
  • MDA is exploring development of an upgraded version of THAAD known as THAAD extended range, which is designed to counter ultrafast gliding weapons. China, for example, has tested such weapons that travel at Mach 10 speeds.
  • The U.S. and South Korea decided in July 2016 to deploy a THAAD battery in South Korea to counter North Korean threats despite strong objections from China. The battery began operating in April 2017.
  • A THAAD battery was deployed to Guam in 2013 to counter potential North Korea IRBM threats to the island and U.S. military assets there. The first test of the THAAD system against an IRBM target occurred in July 2017.


Program & Key Elements

  • PAC-3 consists of a one-piece, hit-to-kill missile interceptor fired from a mobile launching station, which can carry 16 PAC-3 missiles.
  • The missile is guided by an independent radar that sends its tracking data to the missile through a mobile engagement control station.
  • A blast fragmentation kills the target.

Designed to Counter

  • PAC-3 is designed to defend against short- and medium-range ballistic missiles in their terminal stage at lower altitudes than the THAAD system.


  • PAC-3s destroyed two Iraqi short-range ballistic missiles during the 2003 conflict and shot down a U.S. fighter jet. Earlier Patriot models also deployed to the region shot down nine Iraqi missiles and a British combat aircraft.

Capability / Schedule

  • PAC-3 is now considered operational and has been deployed to several countries including the Bahrain, Egypt, Germany, Greece, Israel, Japan, Jordan, Kuwait, the Netherlands, Saudi Arabia, South Korea, Spain, Taiwan, and the UAE.
  • Starting in January 2013, NATO has provided five PATRIOT batteries to Turkey to increase its air defenses.
  • As of 2015, 1,280 Patriot launchers have been produced and the U.S. stocks around 1,100 launchers.


Program Elements

  • Key Elements: 1) geosynchronous (GEO) satellites orbiting the earth; 2) sensors on host satellites in highly elliptical earth orbit (HEO).

Dates Operational

  • Primary objective is to provide early warning of theater and strategic missile launches.
  • Provides data for technical intelligence and battlespace awareness.


  • Currently there are three SBIRS sensors mounted on host satellites in highly elliptical orbit (HEO-1, HEO-2, and HEO-3).
  • Two GEO satellites in orbit. Launch dates: May 7, 2011, and March 19, 2013.
  • The program is projected to cost $19 billion – four times its initial estimates.

Major Issues

  • The first sensor in highly elliptical orbit—HEO-1—was certified for operations by U.S. Strategic Command in December 2008. HEO-2 and HEO-3 are both operational, and HEO-4 has been shipped.
  • GEO-4 is scheduled to launch sometime in 2016 (but has not as of July 2016) while GEO-3 will launch no earlier than September 2017.
  • Lockheed Martin is under contract to produce GEO-5 and GEO-6.


A number of high-profile missile defense efforts that began during the George W. Bush administration were canceled by President Bush’s last Defense Secretary, Robert Gates. Below is a summary of some of these programs, the reason they were canceled, and the amount of money that was spent to develop them.

(Previously known as Space-based Infrared System-low (SBIRS-low))

Program Elements

The program was a planned network of 9-12 satellites which were expected to support U.S. missile defense systems by providing tracking data from space on missiles during their entire flight.

Dates of Program

October 2009 – April 2013

Money Spent

Over $230 million

Major Issues

As reported by the LA Times, outside experts found that the satellites would not have been able to detect warheads flying over the arctic. In order to provide continuous tracking of the missiles, MDA would have actually needed at least 24 satellites. An independent cost assessment projected the total cost of the system to be $24 billion over 20 years instead of the $10 billion MDA projected.


Program Elements

The original program included a modified Boeing 747 plane equipped with a chemical oxygen-iodine laser (COIL) and two tracking lasers. The laser beam would be produced by a chemical reaction. The objective was to shoot down ballistic missiles during their boost phase right after launch but the system could also be used for other missions.

Dates of Program

November 1996 – February 2012

Money Spent

$5.3 billion

Major Issues

The laser would have had a limited range which meant the 747 would have been vulnerable to anti-aircraft missiles. To increase the range, the laser would have needed to be 20-30 times more powerful than planned.


Program Elements

KEI was to be comprised of three powerful boosters and a separating kill vehicle. The booster was expected to travel at least six kilometers per second, which is comparable to an ICBM. The kill vehicle was not designed to carry an explosive warhead but to destroy its target through the force of a collision.

Dates of Program

March 2003 – June 2009 

Money Spent

$1.7 billion

Major Issues

In order to carry the KEI, Navy ships would have needed to be retrofitted. The range was not great enough to be land-based.


Program Elements

The program was designed to launch multiple kill vehicles from a single booster in order to increase the odds of destroying an incoming missile. It was designed to destroy both missiles and decoys.

Dates of Program

January 2004 – April 2009

Money Spent

~$700 million

Major Issues

The program was canceled by the Obama administration in order to focus on “proven, near-term missile defense programs that can provide more immediate defenses of the United States.”


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 both decoys and actual ICBMs. MDA hopes to begin a full development program by FY 2022.

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.

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.


In recent years Congress has sought to encourage the Obama administration to expand the U.S. ballistic missile defense effort in the face of advancing adversary ballistic missile capabilities. These initiatives, which aare summarized below, have been met with strong resistance from the administration.

A Third National Missile Defense Site on the U.S. East Coat

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 still has no plans to actually build such a site. The draft environmental impact statement, which was posted on the website of the Missile Defense Agency (MDA) May 31, said that the Defense Department “does not propose and has not made a decision to deploy or construct an additional interceptor site.” A final environ­mental statement designating a preferred location for the additional site has not been completed and will be further studied as part the department’s broad review of U.S. missile defense policy. Pentagon officials have repeatedly stated that the estimated $3-4 billion price tag of a third interceptor site would be better spent to upgrade the existing GMD system.

Space-based Missile Defense

The FY 2017 National Defense Authorization Act allows the Pentagon to begin design, research and development, and testing for a space-based missile defense system. The Obama administration argued that there is no requirement for a space-based intercept system and there are concerns about the technical feasibility and long-term affordability of interceptors in space.

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.” 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.

Posted: August 17, 2016