Terminal High Altitude Area Defense. Terminal High Altitude Area Defense (THAAD), formerly Theater High Altitude Area Defense, is an American anti-ballistic missile defense system designed to intercept and destroy short-, medium-, and intermediate-range ballistic missiles in their terminal phase (descent or reentry). The THAAD interceptor carries no warhead, instead relying on its kinetic energy of impact to destroy the incoming missile. THAAD was developed after the experience of Iraq's Scud missile attacks during the Gulf War in 1991.

Originally a United States Army program, THAAD has come under the umbrella of the Missile Defense Agency. The Navy has a similar program, the sea-based Aegis Ballistic Missile Defense System, which also has a land component ("Aegis Ashore"). THAAD was originally scheduled for deployment in 2012, but initial deployment took place in May 2008. THAAD has been deployed in the United Arab Emirates (UAE), Israel, Romania, and South Korea.

On 17 January 2022, THAAD made its first operational interception of an incoming hostile medium-range ballistic missile in the UAE.

Development 

The THAAD missile defense concept was proposed in 1987, with a formal request for proposals submitted to industry in 1991. The THAAD program benefited from results of previous missile defense efforts like High Endoatmospheric Defense Interceptor (HEDI) and the Kinetic Kill Vehicle Integrated Technology Experiment (KITE). In September 1992, the US Army selected Lockheed, now Lockheed Martin, as the prime contractor for THAAD development. 

Prior to the development of a physical prototype, the Aero-Optical Effect (AOE) software code was developed to validate the intended operational profile of Lockheed's proposed design. In April 1995, the first THAAD flight test occurred , with all flight tests in the demonstration-validation (DEM-VAL) program phase occurring at White Sands Missile Range. The first six intercept attempts missed the target (Flights 4–9). The first successful intercepts were conducted on 10 June 1999 and 2 August 1999, against Hera missiles.

The vulnerability and lethality analyses of THAAD have been conducted by the U.S. Army Research Laboratory (ARL). The vulnerability assessment for the THAAD featured an evaluation of the effects of major electromagnetic elements. This included EM interference, EM radiation operations, EM radiation hazards, EM pulse, electrostatic discharge, and lightning effects on components of the THAAD system.

The ARL assessments were designed to determine the THAAD system's growth potential given its tactical design as well as provide survivability analysis against threats such as conventional weapons, chemical weapons, and electronic warfare countermeasures. The data collected from the analyses were used to develop trajectory models for targets and missile as well as target trajectories using infrared scene generation of infrared countermeasures (IRCMs).

The THAAD system is being designed, built, and integrated by Lockheed Martin Missiles and Fire Control acting as prime contractor. Key subcontractors include Raytheon, Boeing, Aerojet Rocketdyne, Honeywell, BAE Systems, Oshkosh Defense, and MiltonCAT.

Engineering and manufacturing 
In June 2000, Lockheed won the Engineering and Manufacturing Development (EMD) contract to turn the design into a mobile tactical army fire unit. In 2006, flight tests of this system resumed with missile characterization and full system tests at White Sands Missile Range, then moved to the Pacific Missile Range Facility. The Interceptor was led through development and initial production by Tory Bruno, who later became the CEO of United Launch Alliance.

THAAD-ER 
Lockheed is pushing for funding for the development of an extended-range (ER) version of the THAAD, to counter maturing threats posed by hypersonic glide vehicles that adversaries may deploy, namely the Chinese WU-14, to penetrate the gap between low- and high-altitude missile defenses. The company performed static fire trials of a modified THAAD booster in 2006 and continued to fund the project until 2008. The current -diameter single-stage booster design would be expanded to a  first stage for greater range with a second "kick stage", to close the distance to the target and provide improved velocity at burnout and more lateral movement during an engagement. 

Although the kill vehicle would not need redesign, the ground-based launcher would have only five missiles instead of eight. As of 2020, THAAD-ER is only an industry concept, but Lockheed believes that the Missile Defense Agency will show interest because of the weapons under development by potential adversaries. If funding for the THAAD-ER begins in 2020, a system could be produced by 2024 to provide an interim capability against a rudimentary hypersonic threat. The Pentagon is researching whether other technologies like directed energy weapons and railguns are better solutions for missile defense. These are expected to become available in the mid to late 2020s.

Production 

Sometimes called Kinetic Kill technology, the THAAD missile destroys missiles by colliding with them, using hit-to-kill technology, like the MIM-104 Patriot PAC-3, although the PAC-3 also contains a small explosive warhead. This is unlike the Patriot PAC-2, which carried only an explosive warhead detonated using a proximity fuze. Although the actual figures are classified, THAAD missiles have an estimated range of 125 miles (200 km), and can reach an altitude of 93 miles (150 km). A THAAD battery consists of at least six launcher vehicles, each equipped with eight missiles, with two mobile tactical operations centers (TOCs) and the AN/TPY-2 ground-based radar (GBR). 

The U.S. Army plans to field at least six THAAD batteries, at a purchase cost of US$800 million per battery. In September 2018, the MDA planned to deliver 52 more interceptors to the Army. In June 2020 the Senate Armed Services Committee draft of the FY2021 DoD budget allocated funding for the eighth THAAD battery.

The THAAD missile is manufactured at a Lockheed Martin facility near Troy, Alabama. The facility performs final integration, assembly and testing of the THAAD missile. The THAAD Radar is an X-Band active electronically scanned array Radar developed and built by Raytheon at its Andover, Massachusetts Integrated Air Defense Facility. The THAAD radar and a variant developed as a forward sensor for ICBM missile defense, the Forward-Based X-Band – Transportable (FBX-T) radar, were assigned a common designator, AN/TPY-2, in late 2006/early 2007. The THAAD radar can interoperate with Aegis and Patriot systems, in a 3-layer antimissile defense.

First units equipped (FUE) 
On 28 May 2008, the U.S. Army activated Alpha Battery, 4th Air Defense Artillery Regiment (A-4), 11th Air Defense Artillery Brigade at Fort Bliss, Texas. Battery A-4 is part of the 32nd Army Air & Missile Defense Command. At the time, the battery had 24 THAAD interceptors, three THAAD launchers based on the M1120 HEMTT Load Handling System, a THAAD Fire Control and a THAAD radar. Full fielding began in 2009. In October 2009, the U.S. Army and the Missile Defense Agency activated the second Terminal High Altitude Area Defense Battery, Alpha Battery, 2nd Air Defense Artillery Regiment (A-2), at Fort Bliss.

In August 2012, Lockheed received a $150 million contract from the Missile Defense Agency (MDA) to produce THAAD Weapon System launchers and fire control and communications equipment for the U.S. Army. The contract included 12 launchers, two fire control and communications units, and support equipment. The contract provided six launchers for THAAD Battery 5 and an additional three launchers each to Batteries 1 and 2. These deliveries will bring all batteries to the standard six launcher configuration.

General missile defense plans
In May 2017, the Pentagon proposed spending $7.9 billion in its FY 2018 budget on missile defense, which includes THAAD interceptors and Patriot interceptors, along with $1.5 billion for Ground-based Midcourse Defense (GMD) against intercontinental ballistic missiles.

Deployments

Israel
In 2012, the U.S. AN/TPY-2 early missile warning radar station on Mt. Keren in the Negev desert was the only active foreign military installation in Israel.

In March 2019, Bravo Battery, 2nd Air Defense Artillery Regiment (B-2 THAAD), 11th Air Defense Artillery Brigade was deployed at Nevatim Airbase during a joint US-Israeli drill, after which it moved to an undisclosed location in the Negev desert in southern Israel. The X-Band radar system, which is part of the THAAD system, has been deployed at Nevatim since 2008.

On 13 October 2024, President Biden directed Secretary of Defense Lloyd Austin to authorize the deployment of a THAAD battery to Israel to "help bolster Israel's air defenses following Iran's unprecedented attacks against Israel on April 13 and again on October 1."

On 27 December 2024, a THAAD battery conducted a successful combat interception of a ballistic missile fired from Yemen.

Romania
In 2019, while the Aegis Ashore at NSF Deveselu was being upgraded, B Battery, 62nd Air Defense Artillery Regiment (B-62 THAAD), was emplaced in NSF Deveselu, Romania during the interim.

South Korea

In October 2013, the South Korean military asked the Pentagon to provide information on the THAAD system concerning prices and capabilities as part of efforts to strengthen defenses against North Korean ballistic missiles. However, South Korean Park Geun-hye administration decided it will develop its own indigenous long-range surface-to-air missile instead of buying the THAAD. South Korean Defense Ministry officials previously requested information on the THAAD, as well as other missile interceptors like the Israeli Arrow 3, with the intention of researching systems for domestic technology development rather than for purchase. Officials did however state that American deployment of the THAAD system would help in countering North Korean missile threats. In May 2014, the Pentagon revealed it was studying sites to base THAAD batteries in South Korea.

The deployment was opposed by China and Russia. In February 2016, Chinese Foreign Minister Wang Yi said that having THAAD in South Korea would "shatter the regional strategic balance" and that the system exceeded South Korea's need. In 2017, a Chinese military official said that the deployment had a negative influence on "bilateral military ties and mutual trust" with the United States. Western experts say that the range of THAAD's radar and interceptors should not pose a threat to China, and the U.S. has had similar capabilities in Taiwan and Japan for years. 

Chinese officials believe that its location in South Korea would allow THAAD's radar to detect Chinese missile launches from behind during their boost phase and differentiate between decoys and warheads, sharing information with the rest of the U.S.-led network. This would erode China's nuclear deterrence, which has a much smaller stockpile compared to the United States and Russia. Missile tests in China usually pointed away from Korea, but that trajectory may also need to be reversed in order to minimize detection by THAAD. Chinese officials asked South Korea to downgrade the radar of the missile defence system, but no adjustments were made.

In July 2016, American and South Korean military officials announced the deployment of THAAD system in South Korea, following ballistic missile and nuclear tests by North Korea. Each THAAD unit consists of six truck-mounted launchers, 48 interceptors, a fire control and communications unit, and an AN/TPY-2 radar. Seongju County in North Gyeongsang Province was chosen as a THAAD site, partly because it is out of range of North Korean rocket artillery along the DMZ. This sparked protests from Seongju County residents, who feared that radiation emitted by the AN/TPY-2 radar would impact their health, and damage the region's famed oriental melon crop. On 30 September 2016, the U.S. and South Korea announced that THAAD would be relocated to the Lotte Skyhill Seongju Country Club, farther from the town's main residential areas and higher in elevation, to alleviate concerns.

On 6 March 2017, two THAAD launcher trucks arrived by air transport at Osan Air Base South Korea, for a deployment. Earlier that day, North Korea had launched 4 missiles. A Reuters article stated that with the THAAD defense system, a North Korean missile barrage would still pose a threat to South Korea, while an article in the International Journal of Space Politics & Policy said that South Korean forces already possess Patriot systems for point defense and Aegis destroyers capable of stopping ballistic missiles that may come from the north, in a three-layer antimissile defense for South Korea. On 16 March 2017, a THAAD radar arrived in South Korea. The THAAD system is kept at Osan Air Base until the site where the system is due to be deployed is prepared, with an expected ready date of June 2017. Osan Air Base has blast-hardened command posts with 3 levels of blast doors.

By 25 April 2017, six trailers carrying the THAAD radar, interceptor launchers, communications, and support equipment entered the Seongju site. On 30 April 2017, it was reported that South Korea would bear the cost of the land and facilities for THAAD, while the US will pay for operating it. On 2 May 2017, Moon Sang-gyun, with the South Korean Defense Ministry, and Col. Robert Manning III, a spokesman for the U.S. military, announced that the THAAD system in Seongju is operational and "has the ability to intercept North Korean missiles and defend South Korea." 

It was reported that the system would not reach its full operational potential until later in 2017, when additional elements of the system were onsite. On 7 June 2017 President Moon Jae-in suspended further THAAD deployment pending a review, after discovering four additional launchers had entered South Korea without the defense ministry informing him. The 35th Air Defense Artillery Brigade (United States) has integrated THAAD into its layered defense on the Korean Peninsula, denoted Combined Task Force Defender, composed of both US and ROK personnel.

Even in the face of a North Korean ICBM test on 4 July 2017, which newly threatens Alaska, a Kodiak, Alaska-based THAAD interceptor test (FTT-18) against a simulated attack by an Intermediate Range Ballistic Missile had long been planned. FTT-18 was successfully completed by Battery A-2 THAAD (Battery A, 2nd Air Defense Artillery Regiment, Terminal High Altitude Area Defense) of the 11th Air Defense Artillery Brigade (United States) on 11 July 2017. The soldiers used the procedures of an actual combat scenario and were not aware of the IRBM's launch time.

Also in 2017 another Kodiak launch of a THAAD interceptor was scheduled in July, in preparation for a possible ICBM test by North Korea. On 28 July 2017 North Korea launched a test ICBM capable of reaching Los Angeles. In response, President Moon Jae-in called for deployment of the four remaining THAAD launchers which were put on hold when he came to power. 

Lee Jong-kul, of South Korean President Moon Jae-in's Democratic Party of Korea stated "The nuclear and missile capabilities of North Korea…have been upgraded to pose serious threats; the international cooperation system to keep the North in check has been nullified...", citing tensions over the U.S. deployment of the Terminal High Altitude Area Defense anti-missile system in South Korea. The Atlantic Council, in the June 2017 memorandum "Eliminating the Growing Threat Posed by North Korean Nuclear Weapons" to President Trump, recommended a checklist of actions, including the following declarations to North Korea.
 No use of WMDs, or it will result in a unified Korea under Seoul after the North's assured destruction.
 No export of nuclear equipment or fissile material; it will be intercepted, and the US will respond.
 No missile or missile test aimed at ROK (South Korea), Japan, or the US; it can then be shot down or pre-empted.

On 30 July 2017, a Kodiak-sited THAAD interceptor shot down an MRBM which launched over the Pacific Ocean, the 15th successful test. The Missile Defense Agency (MDA) director emphasized the data collection from the intercept, which enhances the modelling and scenario simulation capabilities of the MDA. John Schilling estimates the current accuracy of the North's Hwasong-14 as poor at the mooted ranges which threaten US cities, which would require more testing to prove its accuracy.

In August 2017, The New York Times reviewed the anti-missile options that are available to counter a planned salvo of four Hwasong-12 missiles, were they to be launched in mid-August 2017 from the North, and aimed to land just outside the territorial waters of Guam, a distance of , flying at altitudes exceeding , in a flight of 1,065 seconds (18 minutes). These options for the missile defense of South Korea include "sea-based, Patriots and THAAD" according to General John E. Hyten, commander of U.S. Strategic Command.

On 2 September 2017, the North Korean news agency KCNA released a photograph of an elongated payload, intended to fit in the warhead of one of its missiles. On 3 September 2017 both Japan's Foreign Ministry and the South Korean Joint Chiefs announced the detection of a magnitude 6.3 seismic event, centered near Punggye-ri, which is North Korea's underground nuclear test site. Japan's Foreign Ministry has concluded that the event was the North's sixth nuclear test. 

Choe Sang-hun of the New York Times reports that the test was a major embarrassment for China's Paramount leader Xi Jinping, who was hosting a BRICS summit (Brazil, Russia, India, China, and South Africa) in Xiamen, China. Cheng Xiaohe, an expert on North Korea at China's Renmin University, said the timing of the test appears to be deliberate. China's Foreign Ministry urged the North to "stop taking wrong actions", and agreed that further UN actions are needed to resolve the impending crisis. By creating a thermonuclear-capable payload for at least one of its missiles, the North has created a need for THAAD, which is capable of intercepting ICBM threats at the lower altitudes and ranges estimated for a Hwasong-14 ICBM subjected to the load of a heavier warhead needed to carry a thermonuclear weapon.

In September 2017, BBC analyst Jonathan Marcus predicted a flood of several million refugees at the border of North Korea and China, were the North to be destroyed. China has positioned only two brigades at the border. Marcus points out that China and Russia have proposed the de-nuclearization of Korea and the replacement of the armistice with a peace treaty.

In October 2017, Battery D, 2nd Air Defense Artillery Regiment, Terminal High Altitude Area Defense, reflagged with the 35th Air Defense Artillery Brigade in preparation for a permanent change of station to South Korea. In the interim before THAAD D-2's permanent transfer to South Korea with their families, THAAD Battery A-4 will deploy to South Korea.

The South Korean decision to deploy THAAD to protect itself against North Korea caused backlash and retaliation measures from China.
On 30 October 2017, South Korea and China agreed to normalize relations, previously damaged due to the THAAD deployment.

Turkey
According to U.S. officials the AN/TPY-2 radar was deployed at Turkey's Kürecik Air Force base. The radar was activated in January 2012.

United Arab Emirates
In December 2011, the United Arab Emirates (UAE) signed a deal to purchase the missile defense system. The United Arab Emirates (UAE) graduated its first two THAAD unit classes at Fort Bliss in 2015 and 2016. Its first live-fire exercises with Patriot missiles took place in 2014.

On 17 January 2022, THAAD made its first real-world intercept against an incoming Houthi ballistic missile in the UAE.

United States

Hawaii

In June 2009, the United States deployed a THAAD unit to Hawaii, along with the SBX sea-based radar, to defend against a possible North Korean launch targeting the archipelago.

Guam
In April 2013, the United States declared that Alpha Battery, 4th Air Defense Artillery Regiment (A-4), would be deployed to Guam to defend against a possible North Korean IRBM attack targeting the island. In March 2014, Alpha Battery, 2nd ADA RGT (A-2), did a change of responsibility with A-4 and took over the Defense of Guam Mission. After a successful 12-month deployment by A-4, Delta 2 (D-2) took its place for a 12-month deployment. In 2018-2019 Echo Battery, 3rd ADA Regiment (E-3) deployed to Guam.

Wake Island

In November 2015, a THAAD system was a key component of Campaign Fierce Sentry Flight Test Operational-02 Event 2 (FTO-02 E2), a complex $230 million missile defense system test event conducted at Wake Island and the surrounding ocean areas. The objective was to test the ability of the Aegis Ballistic Missile Defense and THAAD Weapon Systems to defeat a raid of three near-simultaneous air and missile targets, consisting of one medium-range ballistic missile, one short-range ballistic missile and one cruise missile target. During the test, a THAAD system on Wake Island detected and destroyed a short-range target simulating a short-range ballistic missile that was launched by parachute ejected from a C-17 transport aircraft. At the same time, the THAAD system and the USS John Paul Jones guided missile destroyer both launched missiles to intercept a medium-range ballistic missile, launched by parachute from a second C-17.

Future deployments: firm orders and possible plans

Europe and the Middle East
By March 2016, Army Space and Missile Defense Command was considering THAAD deployments to Europe with EUCOM and the Middle East with CENTCOM.

Japan
In November 2015, Japanese Defense Minister Gen Nakatani said he would consider the U.S. deploying the THAAD in Japan to counter the threat of North Korean ballistic missiles. By October 2016, Japan was considering procuring either THAAD or Aegis Ashore to add a new missile defense layer. In May 2017 it was reported that Japan government officials now favor the Aegis Ashore system as it comes with a wider coverage area, which would mean fewer units needed to protect Japan, and it is also cheaper.

At the Center for a New American Security 2017 conference, citing publicly available sources and simulations of strikes against US bases in Asia, two Navy Fellows, Commanders Shugart and Gonzalez, USN noted that two more Patriot batteries, two more Aegis ships, and five more THAAD batteries would counter China's published SRBM (short-range) and MRBM (medium-range) capabilities against Japan.

Russia has opposed the missile acquisitions and fears that the US will have access to the management of Aegis Ashore missile defense complexes after their deployment in Japan. "We do not know of any cases anywhere in the world when the United States deployed its weapons and transferred control over them to the country in whose territory it all happened. I very much doubt that they will make an exception and in this case," concluded the Russian Foreign Minister.

In 2020, Japan suspended plans to acquire the Aegis Ashore system. The Japanese government said that they were concerned about environmental issues caused by the system dropping spent boosters. Local citizens of the areas chosen to place the system also protested the acquisition, saying that such placement would guarantee strikes on their homes during wartime.  the Japanese government had not made it clear whether or not they would re-evaluate purchasing THAAD systems.

Oman
In May 2013, Oman announced a deal for the acquisition of the THAAD air defense system. However, a sale has not been announced.

Saudi Arabia
In October 2017, the US reached a deal to provide Saudi Arabia with THAAD, in a deal worth $15 billion. The deal included seven fire units, each with a Raytheon AN/TPY-2 radar, two mobile tactical stations (with two spares for a total of 16), and six launchers (with two spares for a total of 44), and 360 interceptor missiles.

Taiwan

In 2017, a Hong Kong–based media report claimed that THAAD could be deployed in Taiwan to intercept People's Republic of China missiles. However, Taiwan's Foreign Minister, David Lee, said he was unaware of any talks with the US about possible deployment. Local military experts said that it was neither necessary nor affordable for Taiwan to deploy THAAD because China is threatening Taiwan with short-range missiles, whereas THAAD is designed to shoot down medium and long-range missiles. 

In March 2017, the Minister of National Defense, Feng Shih-kuan, said that he was firmly opposed to the deployment of a THAAD system in Taiwan. Feng's deputy minister, Cheng De-mei, during a Foreign Affairs and National Defense Committee Q&A session held in April 2017, said that Taiwan did not need a THAAD system in the short term because its US-made phased-array radar system at Hsinchu County’s Leshan base was on par with the THAAD system in terms of detection capability; this was described as being "in slight contrast with Minister of National Defense Feng Shih-kuan's last month." 

Freddy Lim urged the ministry during the same Q&A session "to procure whatever is necessary to ensure the nation’s defense capabilities, which could not be compromised due to China's pressure." Taiwan's existing early warning system, built by the manufacturer of the THAAD radar, can serve to counter China's missile launches.

Operators

The US has 7 batteries of THAAD, which will expand to 8 batteries in the future.
 United States Army
A Battery, 2nd Air Defense Artillery Regiment (A-2 ADA) 
B Battery, 2nd Air Defense Artillery Regiment (B-2 ADA)
D Battery, 2nd Air Defense Artillery Regiment (D-2 ADA)
E Battery, 3rd Air Defense Artillery Regiment (E-3 ADA) 
 A Battery, 4th Air Defense Artillery Regiment (A-4 ADA)
B Battery, 62nd Air Defense Artillery Regiment (B-62 ADA) 
 E Battery, 62nd Air Defense Artillery Regiment (E-62 ADA)

See also 
 Arrow (Israeli missile)
 Comparison of anti-ballistic missile systems
 
 
 
 Prithvi Defence Vehicle—Indian high altitude anti-ballistic missile system
 Project Kusha, under development by India
 
 
 Taiwan Sky Bow Ballistic Missile Defense System

References

External links

 Lockheed Martin THAAD web page
 MDA THAAD page
 THAAD program details
 THAAD program history on designation-systems.net
 TPY-2 X-band Radar on Missile Threat CSIS site

DEM-VAL and EMD testing
 THAAD First Successful Intercept, 10 June 1999
 THAAD Second Successful Intercept, 2 August 1999
 THAAD Equipment Arrives in Hawaii, 18 October 2006
 Successful THAAD Radar Target Tracking Test, 8 March 2007
 THAAD Radar Supports Successful Aegis BMD Intercept, 22 June 2007

Missile Defense Agency
Missile defense
Anti-aircraft warfare
Anti-ballistic missiles of the United States
Surface-to-air missiles of the United States
Lockheed Martin
Boeing
Honeywell
BAE Systems
Raytheon Company
Rocketdyne
Anti-South Korean sentiment in China
Military equipment introduced in the 2000s
Israel–United States military relations
South Korea–United States military relations
Romania–United States military relations
United Arab Emirates–United States relations