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The MIM-104 Patriot is the U.S. Army’s primary air and missile defense system. While initially designed as an antiaircraft system, newer variants of Patriot are capable of engaging ballistic and cruise missiles, loitering munitions, and aircraft. A typical Patriot battery includes a radar set, engagement control station, power generation and other support vehicles, and several launch stations. 18 countries currently operate Patriot.


The U.S. Army Missile Command first developed the Patriot concept in 1961 as the Army Air Defense System for the 1970s (AADS-70s). In its initial form, AADS-70s was to be a mobile air defense system to replace static HAWK and Nike Hercules emplacements. In October 1964, the Army renamed the program to Surface-to-Air Missile, Development (SAM-D) and in 1967, selected a prime contractor for the effort. SAM-D’s first flight test took place in November 1969.1

On January 10, 1974, the Department of Defense reoriented the SAM-D program to support a Track-Via-Missile (TVM) guidance system and a simplified concept of operations. The revised SAM-D entered engineering development in February 1976 and on May 21, 1976, was renamed PATRIOT (Phased Array Tracking Radar to Intercept On Target). Patriot entered full-rate production in in September 1980. The Army activated its first Patriot missile battalion in May 1982.2

Through the 1980s and 1990s, the Army fielded a number of significant upgrades to the Patriot system. As Patriot entered high-rate production through 1985, the Department of Defense began efforts to add a ballistic missile defense capability to the system. In 1986, the Army upgraded Patriot to the Patriot Advanced Capability-1 (PAC-1) standard, which featured software changes that would allow it to engage tactical ballistic missiles. After a successful interception of a Lance missile in September 1986, PAC-1 was deployed in July 1988.3

Following the PAC-1 deployment, the Army embarked on a second upgrade program, PAC-2, which involved modifications to the missile fuze, warhead, and guidance to engage more capable ballistic missiles like the Soviet OTR-23.4 In 1993, the Army upgraded Patriot to a support remote launch capability, allowing launchers to be deployed up to 10km from the radar.5 This reportedly quintupled the system’s defended area from 10-20 square kilometers to roughly 50-100 square kilometers.6 Successive upgrades to the system’s Patriot Advanced Capability-2 (PAC-2) missiles and radar achieved further improvements in performance.

The most significant Patriot enhancement, however, involved the development of a new interceptor with hit-to-kill technology, which would defeat targets by striking them directly. This weapon would later be known as the Patriot Advanced Capability-3 (PAC-3).7 The Army began concept development for a hit-to-kill weapon in 1983 and from 1984, and in May 21, 1987, flight tested the Flexible Lightweight Agile Guided Experiment (FLAGE), intercepting a Lance ballistic missile.8

A follow-on missile named Extended Range Intercept Technology (ERINT) completed final design review in December 1989 and underwent flight tests from 1992 to 1994.9 This became the basis for the PAC-3 interceptor. The U.S. Army had established a PAC-3 Project Office in 1991, and on May 19, 1994, the Defense Acquisition Board selected ERINT for development as the PAC-3. 10 This was to be deployed in the third phase of the PAC-3 development, termed PAC-3 Configuration 3. The first two phases, Configuration 1 and 2, involved upgrades to Patriot’s radar and software, and entered service in 1995 and 1998 respectively.

The PAC-3 missile began flight testing in 1997.11 From March to June 2000, PAC-3 Configuration 3 underwent a Limited User Test (LUT) with the U.S. Army and entered low rate initial production. It achieved an initial operating capability in 2001, and was declared combat ready in August 2002.12 The Army scheduled further production of 100 missiles in 2002, and in 2003, employed the first PAC-3 units in combat during Operation Iraqi Freedom.13

September 29, 1997DT-1First flight test of missile; no seeker or target
December 15, 1997DT-2Flight test without seeker or target
March 15, 1999Characterization FlightSuccessIntercepted short-range ballistic missile (SRBM) with submunition warhead
September 16, 1999DT-3SuccessIntercepted SRBM with bulk chemical warhead
February 5, 2000DT-5SuccessIntercepted SRBM conducting “low-magnitude helix maneuver.” Remote launch; launcher 8km away 8km away from sensor.
July 22, 2000DT-7SuccessIntercepted cruise missile
July 28, 2000EOR-ASuccessIntercepted cruise missile
October 14, 2000DT-6SuccessIntercepted SRBM with submunition warhead; simultaneously launched PAC-2 failed
March 2001DT-8SuccessTwo PAC-3s fired at SRBM target; first hit successful, second unit self-destructed after target was destroyed
July 2001DT-9Partial successDestroyed jamming aircraft target; second PAC-3 failed to intercept SRBM after communications anomaly
October 2001DT-10SuccessDestroyed cruise missile, simultaneous PAC-2 destroyed aircraft. Final test in initial operational testing
March 4, 2004ATM 2-1SuccessFollow-on operational test; Two PAC-3s fired at SRBM target (modified Patriot missile), first hit successful, second unit self-destructed after target was destroyed
September 2, 2004DT-11SuccessFirst test of Cost Reduction Initiative (CRI) missile. 2-missile salvo destroyed SRBM (modified Patriot) target, one missile destroyed cruise missile
Timeline of PAC-3 developmental tests

In March 2009, the Army conducted its first guided flight test of an upgraded PAC-3 interceptor, the PAC-3 Missile Segment Enhancement (MSE). The PAC-3 MSE features an enlarged motor and other enhancements to nearly double the PAC-3’s range. The test was unsuccessful after the second pulse of the missile motor failed to ignite.14 In a second flight test in February 2010, the Army successfully intercepted a tactical ballistic missile target with a salvo of two interceptors. The first interceptor failed to launch.15 The PAC-3 MSE was approved for low-rate initial production in 2014 and achieved initial operational capability in late 2016.16 The Army approved full rate production for the PAC-3 MSE in 2018.17

March 2009FT-7-2FailureFirst SRBM intercept attempt at White Sands Missile Range
February 2010FT-7-2APartial success2 missiles fired; first failed to launch and second intercepted SRBM target
January 2012FT-7-3Success2 missiles fired; first intercepted SRBM target and second intercepted destroyed SRBM debris. Test demonstrated intercept “in the extended MSE battlespace”
November 2012MEADS FT-1Success1 missile fired; intercepted cruise missile target
December 2012FT-7-4Success2 missiles fired; intercepted SRBM
June 2013FT-7-5Success2 missiles fired; 2 intercepted SRBM, 1 intercepted cruise missile
November 2013MEADS FT-2Success3 missiles fired; 2 intercepted SRBM, 1 intercepted aircraft target
December 2015P8-4Success2 missiles fired; 2 intercepted SRBM
March 2016P8-3Success1 missile fired; MSE intercepted SRBM in salvo with PAC-2 GEM-T
July 2016P8-1Success1 missile fired; MSE intercepted aircraft target, but target did not employ electronic countermeasures while maneuvering
June 2017MFT-A1Success2 missiles fired; MSE intercepted SRBM target and cruise missile target
September 2017MFT-BSuccess3 missiles fired; MSE intercepted MRBM target
November 2017MFT-A2Success“Two ripples of interceptors” including MSE and PAC-3 CRI, PAC-2 GEM-T defeated two SRBM targets; MSE intercepted at least one target
February 2020FTP-27 E2Failure2 missiles fired; MSE cued by THAAD remote track data for SRBM target Seekers “did not enter target acquisition during endgame” due to software error
October 2020FTP-27 E1Success2 missiles fired; MSE cued by THAAD remote track data for SRBM target.
Timeline of PAC-3 MSE developmental tests

Patriot system description

The Patriot missile defense system consists of six major components: a 1) missile, 2) launcher, 3) radar set, 4) control station, 5) power generator unit, and 6) high-frequency antenna mast. With continuous upgrades since its fielding, today’s Patriot system bears little resemblance to the original system deployed in 1983.

Patriot Guided Missile

Patriot currently supports two interceptor families: the PAC-2 and the PAC-3. The PAC-2 missile family is a successor to the original Patriot and PAC-1 interceptors, featuring software updates to engage ballistic missiles and an upgraded blast-fragmentation warhead. The missile uses Track-Via-Missile (TVM) guidance in its terminal phase; after being command-guided near the target, the missile passively tracks the target as it is illuminated by the ground-based engagement radar.

An upgraded variant, the PAC-2 Guidance Enhanced Missile (GEM), was developed in the 1990s and featured lighter structures, enhanced propellants, new warhead fuzing, and improved guidance to engage air and ballistic missile targets.18 The PAC-2 GEM Tactical/TBM (GEM-T) and GEM Cruise (GEM-C) are the latest PAC-2 variants and feature further enhancements for engaging ballistic and cruise missile targets, respectively. PAC-2 GEM-T/GEM-C entered Army service in 2002.

The PAC-3 missile family is a clean-sheet departure from the original Patriot/PAC-2 design. It is smaller in diameter and uses hit-to-kill technology, rather than a blast-fragmentation warhead, to destroy agile targets. To achieve its higher maneuverability, the PAC-3 employs a more responsive airframe design and an array of 180 solid-fueled attitude control motors (ACM) mounted in its forward section. The PAC-3 also features an active Ka-band radar seeker for endgame guidance. With its lighter weight and newer propulsion system, the PAC-3 can reportedly defend an area seven times greater than the PAC-2.19 After deployment of the PAC-3 MSE, the Department of Defense redesignated existing PAC-3 systems as the PAC-3 CRI. Four PAC-3 CRIs can fit in each Patriot launch canister. Each missile weighs 312kg, a third of the weight of a PAC-2-family missile.20

The PAC-3 MSE is an upgraded variant of the PAC-3 with an enlarged, dual-pulse booster and other improvements to guidance, structure, and software. This allows it to cover a significantly larger defended area.21 The MSE is the only PAC-3-family missile in production and in 2017 demonstrated the ability to intercept MRBM targets.

Launching Station

The Patriot system employs three launcher variants, the M901, M902, and M903. The first-generation M901 is compatible only with the PAC-2 interceptor and can carry up to four canisters with one interceptor each. The M902 can fit four PAC-2 canisters or 16 PAC-3 CRI missiles in four canisters. The M903 can fit up to 4 PAC-2 GEM, 16 PAC-3 CRI, 12 PAC-3 MSE, or a mixed load of multiple variants, such as with 6 MSE and 8 CRI missiles.22 PAC-3 MSE missiles are single-packed into individual canisters.23 Each launch system typically includes an onboard 15kW generator and is pulled by an M983 truck. A typical Patriot battery includes six to eight launching stations.24

Patriot Radar Set

Patriot currently employs a single AN/MPQ-53, AN/MPQ-65, or AN/MPQ-65A radar set to detect and engage targets. Unlike other air defense systems, the Patriot radar is notable for combining surveillance, tracking, and engagement functions in one unit. This enables a significantly reduced logistical footprint and simplified concept of operations. The AN/MPQ-53 was the world’s first phased-array air defense radar and was employed with legacy PAC-2 systems. To support the PAC-3 and PAC-3 MSE’s extended range, the Army developed a new radar, the AN/MPQ-65, and a further digitized upgrade—the AN/MPQ-65A—which features a 30% increase in range. As of 2019, 9 of 15 U.S. Army Patriot battalions featured the AN/MPQ-65A radar.25

The Army intends to replace these systems with a new radar, the Lower Tier Air and Missile Defense System (LTAMDS), in 2022. Unlike the AN/MPQ-53, -65, and -65A, which can scan only a limited sector of airspace, LTAMDS will possess 360-degree coverage and offer significantly further detection range. While the AN/MPQ-53 and -65-series radars are passively-scanned arrays, LTAMDS is an active electronically scanned array (AESA) and features gallium nitride (GaN) power amplifiers, offering higher jamming resistance, beam agility, and power efficiency over previous systems. The Army issued an initial contract award for six LTAMDS units in October 2019, with the first systems scheduled for delivery in mid-2021.26

Patriot Engagement Control Station

The AN/MSQ-4 Engagement Control Station (ECS), based on an M927 truck, is the only manned component of a Patriot battery. Patriot engagements are nearly autonomous, with only the final launch decision requiring human interaction. The ECS has two computer consoles, and seats two to four operators: a tactical control officer, tactical control assistant, and communications operator. The tactical control assistant executes interceptor launch commands, the tactical control officer approves targets and confirms appropriate rules of engagement, and a communications operator monitors communications between headquarters and the other batteries. A recorder may also assist the tactical control assistant, recording messages from headquarters.27

The latest upgrade to the Patriot ECS, deployed in 2019, features upgraded consoles, improved identification, friend-or-foe (IFF) systems, enhanced computers and software, and compatibility with the Army’s Integrated Battle Command System (IBCS) battle network.28 By linking with an IBCS-connected Integrated Fire Control Network (IFCN) relay, the Patriot system can use targeting data from other sensor systems to complete an engagement.29 In December 2019, the Army demonstrated its first IBCS-connected intercept of two cruise missile targets with PAC-2 missiles, and in mid-2020, conducted a multi-month Limited User Test (LUT) of the system, downing two cruise missile targets with PAC-3 CRI interceptors on August 13.30

Patriot support systems

The Patriot radar and ECS draw electrical power from a separate Electric Power Plant (EPP) vehicle, which includes 2 150kW generators. To transmit firing instructions to the Launching Stations, the ECS connects with a vehicle named the Antenna Mast Group (AMG) that erects two high-frequency radio masts.31

A Patriot battery may also include an additional Information Coordination Central (ICC) vehicle for command and control. Working in concert with the ECS, the ICC can fuse battery data with higher echelons and coordinate engagement orders among multiple Patriot batteries.32 A new version of the system, the Dismounted Patriot ICC (D-PICC), compresses the system’s functions into several transportable cases for use in fixed positions.33

Service History


The Patriot system first saw combat service during the 1991 Gulf War, defending critical assets in Saudi Arabia, Kuwait, and Israel.34 The decision to deploy Patriot PAC-2 batteries to Israel was viewed as critical for forestalling their involvement in the war.35 While initially lauded, the Patriot missile’s performance in Desert Storm later became a source of controversy. The PAC-2’s 90kg blast-fragmentation warhead occasionally failed to fully destroy incoming missiles, and further studies were inconclusive on the system’s ultimate performance.36 The demand for a system that could catastrophically destroy incoming missile warheads partly drove the requirement for the hit-to-kill PAC-3 interceptor.

Both PAC-2 and PAC-3 systems later saw combat during the U.S.-led invasion of Iraq in 2003. Unlike in the Gulf War, studies concluded that the Patriot deployments were largely effective.37 PAC-3s in Operation Iraqi Freedom reportedly intercepted two Iraqi Scud missiles, with both interceptors successfully defeating the targets. The Army also attempted seven intercepts with PAC-2s, successfully intercepting all targets. During the conflict, Patriot units also caused two fatal friendly fire incidents, downing a British Tornado fighter-bomber and U.S. FA/18 Hornet, killing three pilots. 38

In recent years, foreign operators have used Patriot on several occasions. In 2014, Israel used its Patriot GEM+ missiles to destroy two Hamas drones, two Syrian drones, and a Syrian Su-24.39 In 2016, Israel engaged and missed a small drone from Syria with Patriot and fighter-launched air-to-air missiles.40 Israel intercepted another Syrian drone near the Golan Heights in November 2017, and in 2018, shot down a Syrian drone and Su-24.41

In the Yemeni Civil War, Saudi Arabia and the United Arab Emirates employed Patriot systems to intercept Houthi rockets, missiles, and drones. Since their first reported intercepts in June 2015, the Saudi-led coalition in Yemen has engaged Houthi missiles on up to 177 occasions.42

In 2023, the Ukrainian Armed Forces began operating U.S. and German-supplied Patriot PAC-3 systems in its war with Russia. The first reported engagements of Patriot in Ukraine included the intercept of a Russian Kh-47 “Kinzhal” aeroballistic missile over Kyiv on May 4, 2023. On May 16, 2023, the Ukrainian Air Force claimed it used Patriot to intercept a salvo of six Kinzhal missiles over Kyiv. 43 These engagements likely involved the PAC-3 CRI interceptor. The Patriot battery reportedly suffered minor damage during the attack, possibly from missile debris, but was repaired within days.44

Patriot Operators

18 countries, including the United States, possess or have agreed to purchase the Patriot system. These include the Netherlands, Germany, Japan, Israel, Saudi Arabia, Kuwait, Taiwan, Greece, Spain, South Korea, the UAE, Ukraine, Qatar, Romania, Sweden, Poland, and Bahrain, listed in order of purchase date. The most recent recipients, Romania and Sweden, took delivery of their first Patriot components in September 2020 and April 2021 respectively.45 The United States also frequently deploys Patriot batteries to defend deployed forces abroad, and has rotated units through Bahrain, Germany, Japan, Jordan, Iraq, Saudi Arabia, Kuwait, Qatar, South Korea, the UAE, and Turkey. By early 2021, Patriot units had become the most frequently deployed units in the U.S. Army, with 0.9 soldiers at home station for every one deployed abroad.46 A Patriot missile battery requires about 90 soldiers to operate.47


    1. James D. Crabtree, On Air Defense (Westport: Praeger Publishers, 1994), 164; Christopher F. Foss and James C. O’Halloran, IHS Jane’s Land Warfare Platforms: Artillery and Air Defense (London: IHS Janes, 2012-2013), 742-752; “Patriot,” U.S. Army Aviation and Missile Life Cycle Management Command, n.d.,; J. Daniel Sherman, “Patriot PAC-2 Development and Deployment in the Gulf War,” Acquisition Review Quarterly (Winter 2003), pp. 29 – 45,
    2. Ibid.
    3. Sherman 2003, pp. 33 – 34.
    4. Ibid.
    5. Kenneth P. Werrell, Hitting a Bullet with a Bullet: A History of Ballistic Missile Defense, (Maxwell, AL: Air University, 2000).
    6. Ibid.
    7. Patrick O’Reilly et al., The Patriot PAC-3 Missile Program: An Affordable Integration Approach, (Dallas, TX: Lockheed Martin Vought Systems Corp, 1996),
    8. Ibid.; George Lewis, “Chronology of hit-to-kill missile tests,” MIT, April 16, 1997,
    9. Ibid; James Walker, Seize the High Ground: The Army in Space and Missile Defense, (Redstone Arsenal, AL: U.S. Army Space and Missile Defense Command, 2003).
    10. Ibid.; Werrell 2000; Director of Operational Test and Evaluation, Annual Report FY2001, (Washington, DC: U.S. Department of Defense, 2001),
    11. Ibid.
    12. Ibid.; “Patriot Advanced Capability-3 (PAC-3),” U.S. Army Acquisition Support Center, n.d.,
    13. Defense Science Board, Report of the Defense Science Board Task Force on Patriot System Performance: Report Summary, (Washington, DC: Office of the Under Secretary of Defense for Acquisition, Technology, and Logistics, January 2005),; Director of Operational Test and Evaluation, Annual Report FY2003, (Washington, DC: U.S. Department of Defense, 2003),; Director of Operational Test and Evaluation, Annual Report FY2000, (Washington, DC: U.S. Department of Defense, 2000),
    14. Director of Operational Test and Evaluation, FY 2009 Annual Report (Washington, DC: U.S. Department of Defense, 2009),
    15. Director of Operational Test and Evaluation, FY 2010 Annual Report (Washington, DC: U.S. Department of Defense, 2010),
    16. U.S. Army Acquisition Support Center, n.d.
    17. “PAC-3 MSE,” Lockheed Martin, 2019,
    18. Werrell 2000.
    19. U.S. Congress, House, Subcommittee on Defense, Hearings before a Subcommittee of the Committee on Appropriations: Part 2: Fiscal Year 2008 Defense Posture, 110th Cong., 1st Sess., 2008,
    20. Werrell 2000.
    21. Richard Tomkins, “Lockheed Martin delivers enhanced Patriot interceptor,” United Press International,
      October 6, 2015,
    22. PAC-3 MSE Overview, presentation, Lockheed Martin, 2022,
    23. Ibid.
    24. Operator’s Manual: Launching Station M901 Guided Missile Semitrailer Mounted, TM 9-1440-600-1 (Washington, DC: U.S Army Headquarters, December 1983),; U.S. Army Weapons Systems 1988, (Washington, DC: U.S. Army, 1988),
    25. Gary Sheftick, “Patriot force halfway thru major modernization,” Army News Service, August 22, 2019,
    26. Sydney Freedberg Jr., “Raytheon Readies LTAMDS Radar For Tests,” Breaking Defense, March 16, 2021,
    27. Foss and O’Halloran, 742-752; Jon Hawkes, “Patriot games: Raytheon’s air-defence system continues to proliferate,” Jane’s International Defence Review, Vol. 52, (January 2019),
    28. Ibid.
    29. Director of Operational Test and Evaluation, FY 2020 Annual Report (Washington,
      DC: U.S. Department of Defense, January 2021),
    30. Devon Suits, “Army system successfully completes second missile intercept test,” Army News Service, August 14, 2020,
    31. U.S. Army, Operations and Training Patriot, FM 44-15-1 (Washington, DC: U.S. Army Headquarters, 1987),
    32. Operator’s Manual: Information and Coordination Central, Guided Missile System, Truck Mounted: AN/MSQ-116, TM 9-1430-602-10-1, (Washington, DC: U.S. Army Headquarters, October 1983),
    33. Hawkes 2019; Sallena Samuel, “3rd Battalion, 2nd Air Defense Artillery prepares for deployment,” U.S. Army, January 11, 2018,
    34. Patrick E. Tyler, “U.S. Ships Missiles to Defend Saudis,” The New York Times, September 25, 1991, archived at
    35. J. Michael Kennedy, “U.S. Rushes Defenses to Israel: American Troops to Operate Two Patriot Batteries,” The Los Angeles Times, January 20, 1991,; Joel Brinkley, “No Immediate Retaliation, Israelis Say,” January 23, 1991, The New York Times, archived at
    36. John Kifner, “Deadly Debris Shows Limits of Patriot Missile Defenses,” The New York Times, January 27, 1991, archived at; Government Accountability Office (GAO), Operation Desert Storm: Data Does Not Exist to Conclusively Say How Well Patriot Performed, (Washington DC: GAO, 1992) Report to Congressional Requesters,
    37. Defense Science Board, 2005
    38. Ibid,; Steven A. Hildreth, “Kinetic Energy Kill for Ballistic Missile Defense: A Status Overview,” Congressional Research Service, January 5, 2015, CRS-6 footnote 15,; Jeremy Singer, “Report Cites Patriot Autonomy as a Factor in Friendly Fire Incidents,” Space News, March 14, 2005,
    39. Spencer Ho and Ilan Ben Zion, “IDF shoots down Syrian fighter plane over Golan,” Times of Israel, September 23, 2014,; Yaakov Lappin, “Israeli Patriots, fighter jet miss suspicious drone that intruded from Syria,” The Jerusalem Post, July 17, 2016,; Gili Gohen, “Israel Unsuccessfully Tries to Intercept Drone That Breached Its Airspace,” Haaretz, July 17, 2016,
    40. Ibid.
    41. Anna Ahronheim, “Patriot missile intercepts drone on Israel’s border with Syria,” The Jerusalem Post, November 11, 2017,; Judah Ari Gross, “IDF shoots down Syrian fighter jet that entered Israeli airspace,” The Times of Israel, July 24, 2018,; Judah Ari Gross, “IDF intercepts Syrian drone that penetrated 10 kilometers into Israel,” The Times of Israel, July 11, 2018,
    42. “Interactive: The Missile War in Yemen,” Missile Threat, CSIS Missile Defense Project, October 13, 2016,
    43. Air Force Command of the UA Armed Forces, Facebook Post, May 16, 1:31 AM,
    44. Sophia Ankel, “Russian damage to US-made Patriot system in Ukraine was ‘minor’ and it has already been fixed, Pentagon says,” Business Insider, May 19, 2023,
    45. Radu-Sorin Marinas, “Romania receives Patriot missiles from U.S. to boost defences,” Reuters, September 17, 2020,; “Sweden Receives Advanced Patriot Interceptors,” Missile Threat, CSIS Missile Defense Project, May, 11, 2021,
    46. Lt. General Daniel Karbler, “The Role of Integrated Air and Missile Defense for Strategic Deterrence,” Washington, DC: Center for Strategic and International Studies, May 21, 2021,
    47. Tara Copp and Marcus Weisgerber, “Why the US Won’t Give Patriot Interceptors to Ukraine,” Defense One, March 10, 2022,
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Missile Defense Project, "Patriot," Missile Threat, Center for Strategic and International Studies, June 14, 2018, last modified August 23, 2023,