Terminal High Altitude Area Defense (THAAD)

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Terminal High Altitude Area Defense (THAAD) is a transportable system that intercepts ballistic missiles during their final, or terminal, phase of flight. It incorporates an X-band radar, the AN/TPY-2, and a single-stage, hit-to-kill interceptor to defeat ballistic missiles inside or outside of the atmosphere.

THAAD occupies a middle tier in the United States’ Ballistic Missile Defense System (BMDS), covering a larger defended area than the Patriot while serving as an underlay for the exoatmospheric Aegis BMD and GMD systems. In flight tests, it has demonstrated capability against short-, medium-, and intermediate-range ballistic missiles.

THAAD development

Comparison of THAAD PDRR (left) and EMD (right) interceptors. Photo: Missile Defense Agency

In response to Congressional calls for a “deployable TMD demonstration system,” the Army began developing THAAD, which entered Program Development and Risk Reduction (PDRR) in 1992.1 The Army first test launched a THAAD prototype in April 1995. On December 13, 1995, the Army attempted its first THAAD intercept test, which was unsuccessful. Five successive flights—taking place from 1996 to 1999—also failed, largely due to “quality control deficiencies in the manufacturing of the interceptor.”2

Despite two successful flights in June and August 1999, the Army elected to redesign THAAD and relax its requirement for intercepting targets at lower altitudes. THAAD subsequently entered Engineering and Manufacturing Development (EMD) in June 2000.

April 21, 1995FT-1N/APropulsion test, no target launched
July 31, 1995FT-2N/AKill vehicle controls test, no target launched
October 13, 1995FT-3N/ATarget flyby test; no intercept attempted
December 13, 1995FT-4Failure“Premature kill vehicle fuel consumption” due to software error
March 22, 1996FT-5FailureFailed kill vehicle separation
July 15, 1996FT-6FailureSeeker failure; half of focal plane array malfunctioned
March 6, 1997FT-7FailureDivert thrusters failed to fire due to battery connection failure
May 12, 1998FT-8FailureBooster failure after electrical short circuit from foreign object debris
March 29, 1999FT-9FailureAttitude control system nozzle torn from bracket
June 10, 1999FT-10SuccessIntercepted HERA unitary target
August 2, 1999FT-11SuccessIntercepted HERA separating target
List of THAAD PDRR (prototype model) flight tests.

In its EMD phase, the THAAD intereptor prototype was redesigned to feature more powerful thrust vector control and divert systems, improved computers, and simplified avionics.3 The THAAD EMD missile passed critical design review in December 2003 and the first AN/TPY-2 radar was delivered in March 2004.4

This “next-generation” interceptor underwent its first flight test on November 22, 2005 and its first intercept test on July 12, 2006, where it successfully intercepted a ballistic missile target.5 Between 2006 and 2019, the Army and Missile Defense Agency conducted 18 THAAD intercept tests. 14 of these tests were successful and 4 were cancelled before launch due to target malfunctions.6 The production THAAD system has not failed an intercept test.

November 22, 2005FTT-01N/APropulsion test, no target launched
May 11, 2006FTT-02N/ADemonstration of THAAD radar, launcher, fire control operations against simulated target
July 12, 2006FTT-03SuccessIntercepted unitary target; seeker characterization flight
September 13, 2006FTT-04N/ATarget malfunctioned; no-test declared
January 26, 2007FTT-06Success 
April 5, 2007FTT-07Success 
October 26, 2007FTT-08Success 
June 25, 2008FTT-09Success 
September 17, 2008FTT-10N/ATarget malfunctioned; no-test declared
March 17, 2009FTT-10aSuccess 
December 11, 2009FTT-11N/ATarget malfunctioned; no-test declared
June 28, 2010FTT-14Success 
October 4, 2011FTT-12Success2 targets launched; both intercepted
October 25, 2012FTI-01Success MRBM-class target
September 10, 2013FTO-01Success MRBM-class target
October 4, 2015FTO-02 Event 2N/ATarget malfunctioned; no-test declared
November 1, 2015FTO-02 Event 2aSuccess2 targets (SRBM and MRBM); both intercepted
July 11, 2017FTT-18SuccessFirst intercept of IRBM-class target
July 30, 2017FET-01SuccessMRBM-class target
August 30, 2019FTT-23SuccessMRBM-class target
List of THAAD EMD (production model) flight tests.

THAAD components

THAAD incorporates four main components: the interceptor, launch vehicle, radar, and fire control system.

THAAD interceptor

The THAAD interceptor is 6.2 meters long, 0.4 meters in diameter, and weighs 662 kg at launch.7 It consists of single-stage, solid-propellant booster and a liquid-fueled kinetic kill vehicle. The missile’s booster is constructed from carbon fiber and uses a hydroxyl-terminated polybutadiene (HTPB) propellant. It employs a thrust vector system for control and a deployable rear flare for stability.8 The THAAD kill vehicle is constructed from composites and uses a gimbaled infrared seeker to track targets in the terminal phase.9 After approaching the target with its main booster, the THAAD kill vehicle separates and uses its hydrazine-powered divert thrusters to maneuver in its final trajectory.

The THAAD system defend targets at ranges of 150 – 200 km.10 Unlike other missile defense systems, THAAD can intercept targets within (endoatmospheric) and outside (exoatmospheric) the atmosphere.11

THAAD launcher

The THAAD launcher is based on a 4-axle heavy expanded mobility tactical truck (HEMTT). Each launcher carries up to eight interceptors, which are housed in 6.6 m long, 1,044 kg launch canisters.12 There are eight interceptors per launcher. A typical THAAD battery includes 6 launchers, and each launcher takes up to 30 minutes to reload.13

AN/TPY-2 radar

The THAAD system utilizes the Army Navy/Transportable Radar Surveillance (AN/TPY-2) radar to detect and track enemy missiles at ranges of 870 to 3,000 km.14 The AN/TPY-2 radar is deployable in two modes: a forward-based mode (FBM), where it detects missiles in the ascent phase to cue other BMDS elements, and a terminal mode (TM), where it provides tracking and engagement data for terminal THAAD engagements.15

The AN/TPY-2 radar includes four major subsystems: the main antenna, or Antenna Equipment Unit (AEU), the Electronic Equipment Unit (EEU), the Cooling Equipment Unit (CEU), and the Prime Power Unit (PPU).

The AEU is the main radiating element of the AN/TPY-2 and operates in the X-band. Its high operating resolution allows it to more effectively cue engagements and discriminate targets from decoys and debris. The trailer-mounted system has a 9.2m^2 phased-array antenna face with over 25,000 antenna modules.16

Three other trailers—the EEU, CEU, and PPU—provide the requisite processing, refrigerated coolant, and electrical power to continue operations. The antenna and electronics units connect with THAAD fire control elements with fiber optic cables, and the cooling and power units feed chilled coolant and power to the other radar subsystems.

THAAD Fire Control and Communications System

The THAAD Fire Control and Communications (TFCC) component oversees battery operations and relays fire control information to other elements of the joint force. Each system, known as a Tactical Station Group (TSG), incorporates a Tactical Operations Station (TOS) with two operating stations, a Launch Control Station (LCS), which includes wireless datalinks, networking equipment, and fiber optic cable interfaces, and a Station Support Group (SSG) which includes HMMWV-based antenna and cable support vehicles.

Operating in concert, these systems control battery launch operations and transfer fire control information from the AN/TPY-2 radar to the larger Command, Control, Battle Management, and Communications (C2BMC) network. By connecting with C2BMC, THAAD can exchange tracking data with Aegis, GMD, and Patriot missile defense. MDA first demonstrated a THAAD-cued Patriot intercept in 2020.17

Service history

THAAD launchers. Photo: MDA

The Army initially fielded THAAD in April 2012 with two batteries at Fort Bliss, Texas.18 To facilitate the training of the future THAAD force, the Army opened a training center at Fort Sill, Oklahoma in 2015.19

By the end of 2015, five THAAD batteries were active.20 As of 2019, the United States fields seven THAAD batteries and has deployed three outside of the continental United States, including in Guam and South Korea.21 The United States fields additional FBM AN/TPY-2 radars at Kyogamisaki, Japan; Shariki, Japan; Kürecik, Turkey (Site K); Mt. Keren, Israel (Site 512); and at a fifth, unknown, site, likely in Saudi Arabia (Site 4a).22

In 2013, the Army deployed a THAAD battery to Guam in response to North Korean threats to the island.23 On May 1, 2017, the Army activated its first THAAD system in Seongju, South Korea.24

In April 2019, the United States temporarily deployed THAAD to NATO’s European Phased Adaptive Approach (EPAA) site in Deveselu, Romania as its Aegis Ashore system received maintenance.25 Following drone and missile attacks on Saudi oil facilities, the United States deployed a THAAD battery to Saudi Arabia in October 2019.26 This system was withdrawn in mid-2021.27

Foreign operators

In 2012, the Defense Security Cooperation Agency (DSCA) approved the sale of THAAD to Qatar and the United Arab Emirates, the first foreign military sale of the weapon.28

In 2013, U.S. contractors concluded an initial agreement, valued at $1.135 billion, to supply two THAAD batteries to the UAE. The sale reportedly included up to 192 interceptors, 2 AN/TPY-2 radars, 12 launchers, and other support systems.29 By late 2015, 81 UAE servicemembers had completed THAAD training.30 The UAE activated its first batteries some time in 2016.31

On October 6, 2017, the United States cleared the possible foreign military sale of up to 7 THAAD batteries to Saudi Arabia for an estimated cost of $15 billion.32 U.S. and Saudi officials signed formal terms of sale in November 2018. In April 2019, Lockheed Martin was awarded an initial $2.4 billion contract for THAAD interceptors, and received an additional $1.48 billion award in July 2019.33 In March 2020, Lockheed received a $932 million contract modification for THAAD interceptor production, and, in April 2021, an additional $611 million for support services.34 In addition, Raytheon Technologies received a $2.3 billion award for the sale of seven upgraded, gallium nitride (GaN)-based AN/TPY-2 radars in June 2020.35

On November, 5, 2012, the United States approved the possible sale of up to 2 THAAD batteries to Qatar for an estimated cost of $6.5 billion. The proposed sale would include up to 12 launchers, 150 interceptors, 2 fire control systems, 2 AN/TPY-2 radars, 1 Early Warning Radar (EWR), and associated equipment.36 Due to budget and operational challenges, the sale was not finalized.37


    1. Director of Operational Test and Evaluation, Annual Report FY2001, (Washington, DC: U.S. Department of Defense, February 2002),https://www.dote.osd.mil/Portals/97/pub/reports/FY2001/other/2001DOTEAnnRpt.pdf?ver=2019-11-13-172534-673; John Rhea, “Industry Responds to TMD Challenge,” Air Defense Artillery Magazine (September-October 1991), pp. 6 – 8.
    2. Director of Operational Test and Evaluation, Annual Report FY2000, (Washington, DC: U.S. Department of Defense, February 2001), https://www.dote.osd.mil/Portals/97/pub/reports/FY2000/other/2000DOTEAnnRpt.pdf?ver=2019-11-13-183527-323.
    3. Ibid.
    4. Director of Operational Test and Evaluation, FY 2004 Annual Report, (Washington, DC: U.S. Department of Defense, 2005), https://www.dote.osd.mil/Portals/97/pub/reports/FY2004/other/FY04DOTEAnnRpt1.pdf?ver=2019-11-07-173426-513.
    5. “Lockheed Martin’s THAAD Missile Successful In Developmental Flight Test,” Lockheed Martin, November 22, 2005, https://news.lockheedmartin.com/2005-11-22-Lockheed-Martins-THAAD-Missile-Successful-in-Developmental-Flight-Test.
    6. Missile Defense Agency, Ballistic Missile Defense Intercept Flight Test Record, (Fort Belvoir, VA: Missile Defense Agency, 2021), https://www.mda.mil/global/documents/pdf/testrecord.pdf.
    7. Mark Shackelford, “The weapons of ballistic missile defense,” 30th Air Armament Symposium, Ft. Walton Beach, FL, October 12, 2004, http://www.ndiagulfcoast.com/events/archive/30th_symposium/day1/Brig%20Gen%20Shackelford/ms-106464.pdf.
    8. U.S. Army Space and Missile Defense Command, Theater High Altitude Area Defense (THAAD) Pacific Test Flights: Environmental Assessment, (Huntsville, AL: December 20, 2002, https://www.mda.mil/global/documents/pdf/env_thaad_ea.pdf.
    9. Ibid.
    10. “THAAD Contract Awarded,” Air Defense Artillery (November-December 1992), p. 7″THAAD Missile defense system,” Reuters, May 2, 2017, http://fingfx.thomsonreuters.com/gfx/rngs/SOUTHKOREA-THAAD/0100403L07J/index.html.
    11. Camilla White, “THAAD and Product Support Overview,” MDA Small Business Conference, June 25, 2019, https://www.mda.mil/global/documents/pdf/7%20THAAD%20COL%20Camilla%20White.pdf.
    12. Shackelford 2004
    13. White 2019.
    14. Jaganath Sankaran, “THAAD Radar Ranges,” Mostlymissiledefense, July 17, 2016, https://mostlymissiledefense.com/2016/07/17/thaad-radar-ranges-july-17-2018/.
    15. Ground-based Midcourse Defense Operations, ATP 3-27.3 (Washington, DC: Headquarters Department of the Army, October 2019).
    16. Jagnath Sankaran, “Ballistic Missile Defense: Power of X-Band Radars,” Mostlymissiledefense, June 4, 2012, https://mostlymissiledefense.com/2012/06/04/ballistic-missile-defense-power-of-x-band-radars-june-4-2012/.
    17. Jen Judson, “MDA and Army see successful Patriot and THAAD test after failure,” Defense News, October 1, 2020, https://www.defensenews.com/land/2020/10/01/mda-and-army-see-successful-patriot-and-thaad-test-after-failure/.
    18. Missile Defense Agency, “Terminal High Altitude Area Defense (THAAD),” http://www.mda.mil/system/thaad.html.
    19. C. Todd Lopez, “NCOS Take Over Training at New THAAD Schoolhouse,” NCO Journal, January 28, 2015, http://ncojournal.dodlive.mil/2015/01/28/ncos-take-over-training-at-new-thaad-schoolhouse/.
    20. “Lockheed Martin Receives $528 Million THAAD Missile-Defense Contract,” Lockheed Martin Press Release, January 4, 2016, http://www.lockheedmartin.com/us/news/press-releases/2016/january/mfc-010416-lockheed-martin-receives-528-million-THAAD-contract.html.
    21. White 2019
    22. Leonard Halley, “Sensors Directorate Breakout Session,” MDA 20th Annual Small Business Programs Conference, Ft. Belvoir, VA: June 2019, https://www.mda.mil/global/documents/pdf/Breakout%20Session%20Sensors%20Mr.%20Leonard%20Halley.pdf.
    23. Karen DeYoung, “U.S. to deploy anti-missile system to Guam,” Washington Post, April 3, 2013. https://www.washingtonpost.com/world/national-security/us-to-deploy-anti-missile-system-to-guam/2013/04/03/b939ecfc-9c89-11e2-a941-a19bce7af755_story.html.
    24. Chow Sang-Hun, “U.S. Antimissile System Goes Live in South Korea,” The New York Times, May 2, 2017. https://www.nytimes.com/2017/05/02/world/asia/thaad-north-korea-missile-defense-us.html?_r=0.
    25. Robert N. Durr, “THAAD redeploys from Romania,” U.S. Army, September 4, 2019, https://www.army.mil/article/226644/thaad_redeploys_from_romania.
    26. C. Todd Lopez, “U.S. Sends Additional Capabilities to Saudi Arabia,” DoD News, October 11, 2019, https://www.defense.gov/Explore/News/Article/Article/1988003/us-sends-additional-capabilities-to-saudi-arabia/.
    27. Gordon Lubold, Nancy A. Youssef, and Michael R. Gordon, “U.S. Military to Withdraw Hundreds of Troops, Aircraft, Antimissile Batteries from Middle East,” The Wall Street Journal, June 18, 2021, https://www.wsj.com/articles/u-s-military-to-withdraw-hundreds-of-troops-aircraft-antimissile-batteries-from-middle-east-11624045575.
    28. “U.S. clears sale of Lockheed missile defense system to UAE, Qatar,” Reuters November 6, 2012, http://www.reuters.com/article/us-lockheed-missiles-mideast-idUSBRE8A507J20121106.
    29. Mike Gruss, “Lockheed Wraps Up First Overseas Sale of Regional THAAD System,” Space News, September 30, 2013, http://spacenews.com/37468missile-defense-lockheed-wraps-up-first-overseas-sale-of-regional-thaad-system/#sthash.9wz7RrIM.dpuf.
    30. Adriane Elliot, “Antiballistic system shared with international partner,” U.S. Army Press Release, January 13, 2016, http://www.army.mil/article/160912/Antiballistic_system_shared_with_international_partner/.
    31. Chris Biggers, “UAE THAAD Site Reaches Milestone,” Bellingcat, January 30, 2017, https://www.bellingcat.com/news/mena/2017/01/30/uae-thaad-site-reaches-milestone/.
    32. U.S. Defense Security Cooperation Agency, Saudi Arabia – Terminal High Altitude Area Defense and Related Support, Equipment and Services, (Washington, DC: U.S. Department of State, 2017), https://www.dsca.mil/press-media/major-arms-sales/saudi-arabia-terminal-high-altitude-area-defense-and-related-support.
    33. “Lockheed awarded $1.48 billion Saudi missile defense contract: Pentagon,” Reuters, July 19, 2019, https://www.reuters.com/article/us-lockheed-martin-defense-saudi/lockheed-awarded-1-48-billion-saudi-missile-defense-contract-pentagon-idUSKCN1UE2JQ.
    34. Mike Stone, “Lockheed gets $932 million Pentagon contract for THAAD interceptors,” Reuters, March 24, 2020, https://www.reuters.com/article/us-usa-saudi-thaad/lockheed-gets-932-million-pentagon-contract-for-thaad-interceptors-idUSKBN21B3D3; Matthew Nelson, “Lockheed to Continue Saudi Arabia THAAD Support under $610M Phase II FMS Contract,” GovConWire, April 1, 2021, https://www.govconwire.com/2021/04/lockheed-to-continue-saudi-arabia-thaad-support-under-610m-phase-ii-fms-contract/.
    35. “Raytheon Missiles & Defense Awarded $2.3B Production Contract for Missile Defense Radars,” PRNewswire, June 26, 2020, https://raytheon.mediaroom.com/2020-06-26-Raytheon-Missiles-Defense-awarded-2-3B-production-contract-for-missile-defense-radars.
    36. U.S. Defense Security Cooperation Agency, Qatar – Terminal High Altitude Area Defense (THAAD), (Washington, DC: U.S. Department of State, 2012), https://www.dsca.mil/press-media/major-arms-sales/qatar-terminal-high-altitude-area-defense-thaad.
    37. Kenneth Katzman, Qatar: Governance, Security, and U.S. Policy, R44533, (Washington, DC: Congressional Research Service, 2019), https://crsreports.congress.gov/product/pdf/R/R44533/46.
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Missile Defense Project, "Terminal High Altitude Area Defense (THAAD)," Missile Threat, Center for Strategic and International Studies, June 14, 2018, last modified June 30, 2021, https://missilethreat.csis.org/system/thaad/.