[12] 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.

[14] In June 2000, Lockheed won the Engineering and Manufacturing Development (EMD) contract to turn the design into a mobile tactical army fire unit.

The Interceptor was led through development and initial production by Tory Bruno, who later became the CEO of United Launch Alliance.

[15][40] 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.

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.

A THAAD battery consists of at least six[45] launcher vehicles, each equipped with eight missiles, with two mobile tactical operations centers (TOCs) and the AN/TPY-2 ground-based radar (GBR).

[48][6] In June 2020 the Senate Armed Services Committee draft of the FY2021 DoD budget allocated funding for the eighth THAAD battery.

[56] 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.

[67] 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.

[68] 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.

[77] 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.

[82] 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.

[83] 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.

[88][87] A Reuters article stated that with the THAAD defense system, a North Korean missile barrage would still pose a threat to South Korea,[91] 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,[52][page needed][original research?]

[93]: minute 0:45 By 25 April 2017, six trailers carrying the THAAD radar, interceptor launchers, communications, and support equipment entered the Seongju site.

[99] 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.

[108][109] 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.

[126] On 2 September 2017, the North Korean news agency KCNA released a photograph of an elongated payload,[127] intended to fit in the warhead of one of its missiles.

[128] 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.

[103] The South Korean decision to deploy THAAD to protect itself against North Korea caused backlash and retaliation measures from China.

[143] 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.

[147][148] By March 2016, Army Space and Missile Defense Command was considering THAAD deployments to Europe with EUCOM and the Middle East with CENTCOM.

[149] 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.

[152] At the Center for a New American Security 2017 conference, citing publicly available sources and simulations of strikes against US bases in Asia,[153] 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.

[158] 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.

[164] In 2017, a Hong Kong–based media report claimed that THAAD could be deployed in Taiwan to intercept People's Republic of China missiles.

[166] 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.

"[167] 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.

"[167] Taiwan's existing early warning system, built by the manufacturer of the THAAD radar, can serve to counter China's missile launches.