THAAD in the Korean Peninsula

Backgrounder November, 2016, pp. 10


  • On July 7, 2016, South Korea and the U.S. agreed to deploy a Terminal High Altitude Area Defense (THAAD) in the Korean Peninsula.
  • The South Korean public generally agrees that THAAD should be deployed, local residents however, have opposed hosting it in their region.
  • THAAD has also affected South Korea’s relationships with its neighbors.
  • North Korea sees the deployment of THAAD as an act of aggression.
  • Beijing is concerned that THAAD is an extension of U.S. strategic interest in the region.
  • Divided into four sections, this ISDP backgrounder outlines the development, deployment, positioning and regional impact of THAAD.

The Development of THAAD

The Terminal High Altitude Area Defense, better known as THAAD, is a system developed by Lockheed Martin. Production began in 1992 and the first contract with the U.S. government was signed in January 2007.  The main purpose of THAAD is to defend U.S. troops, allied forces, population centers and critical infrastructure from short- and medium-range missiles. It destroys threats within and outside the earth’s atmosphere.

Technical Specifications

The THAAD system consists of five parts:

  1. launchers,
  2. missiles,
  3. fire control,
  4. the THAAD radar,
  5. support equipment.

THAAD missiles are 6,17 meters in length and have a single stage solid fuel rocket motor with thrust, giving them a launch weight of 900 kilograms. They have a range of 200 kilometers and can reach up to 150 kilometers in altitude, this is higher than any other missile defense systems. The radar, on the other hand, can identify missile threats up to 1,000 kilometers in range.

To defend, THAAD missile uses kinetic energy. THAAD is able to destroy an incoming missile through collision (hit-to-kill). A typical THAAD battery consists of nine launch vehicles, two fire control centers, and a ground-based radar. The launch vehicles are 12 meters in length and 3.25 meters wide and are equipped with eight missiles.

There are two possible modes for THAAD. The first is the forward-based mode, in which the system would be aimed at target detection and tracking of missiles during the boost phase. The second is terminal mode, with the aim of target acquisition, tracking, and discrimination for fire control of the THAAD battery.

Interception Sequence

The sequence of a THAAD interception would start with an enemy launching a missile. The missile would be detected by the THAAD radar system when falling into range and the information would be relayed to the fire control center. The fire control center would then instruct the launch of an interceptor missile. The target object data and predicted intercept point would be downloaded to the missile and the missile would be fired from the launcher at the enemy projectile. The information on the target and interception would continuously be transmitted to the missile while in flight and the enemy projectile would be destroyed when it re-enters the atmosphere (terminal phase). The THAAD system would then have another three interceptor missiles to fire with each individual battery taking 30 minutes to reload.

Success Rate and Acquisition

According to official Lockheed Martin data, THAAD has maintained a 100% mission success rate over its last 13 development and operational tests, which included 11 successful intercepts. U.S. Missile Defense Agency tests reflect the same rate of success. The first foreign military sale of THAAD was in September 2008 to the United Arab Emirates (UAE). Three THAAD fire units were sold, with 147 missiles, four THAAD radars, six fire control centers and nine launchers. Two additional THAAD systems and the support equipment were purchased again by the UAE in 2011.


One of the main characteristics of THAAD is the ease of transportation which make it possible to quickly reposition THAAD. This gives THAAD greater flexibility to respond to changing threats. Whilst alternative Ballistic Missile Defense System (BMDS), such as the Aegis BMD and Patriot/PAC-3, are also transportable, they have a more limited range.

When compared with alternative systems, THAAD can also intercept a wider range of threats. It can intercept both exo- and endo-atmospheric threats, while the Aegis BMD can only intercept exo-atmospheric threats and the Patriot-PAC-3, only endo-atmospheric threats.In addition, THAAD is inter-operable with other BMDS, making it possible to have an integrated air and missile defense system. THAAD can also be used against weapons of mass destruction, i.e., chemical, nuclear and biological warheads.


There are, however, certain limitations to the THAAD system. First of all, THAAD may not be efficient against missiles with an irregular and unstable trajectory as the interceptor missile has to precisely hit and destroy the front side of an incoming missile.

Another challenge is for THAAD’s radar to differentiate between real warheads and decoys. The radar bases its data on the exterior properties of the missile, such as its shape and brightness.When a real warhead is launched among decoys, it would be difficult for the THAAD radar to accurately identify it. Therefore, the probability exists that the THAAD missile will hit a decoy missile while the real warhead continues towards the target.


THAAD Deployment in South Korea

The Need for THAAD

The U.S. has been proposing the deployment of THAAD in the Korean Peninsula since 2014, but it was only in early February 2016 that official discussions started. This was largely a result of North Korea’s fourth nuclear test that was conducted in January 2016. After a series of consultations, the decision to deploy THAAD was made public by the Park Geun-hye administration on July 7th, 2016. The decision was seemingly made overnight and did not go through a ratification process which is required for treaties that would “significantly transform the security environment of South Korea.”

According to a joint statement between the U.S. and South Korea, the purpose of THAAD is to act as a “defensive measure to ensure the security of ROK and its people, and to protect Alliance military forces from North Korea’s weapons of mass destruction and ballistic missile threats.”South Korea would be protected against potential nuclear, biological, or chemical attacks from its northern neighbor and, in addition, Pyongyang would also be limited in its ability to engage in coercive diplomacy.

South Korea’s Defense Capacity

South Korea currently has the Patriot Advanced Capability (PAC) system, a defense system with an operational range of 20 to 35 kilometers. Other than THAAD, South Korea will also be developing an independent Korean Air and Missile Defense system (KAMD) which will serve as lower-altitude interceptors. As THAAD will be inter-operable with these systems, South Korea would have a multi-layered defensive shield against attacks from North Korea.


Based on the Status of Forces Agreement (SOFA), the responsibility to provide for the land and relevant facilities to host THAAD is held by South Korea. The U.S., on the other hand, will provide funding for the deployment and operation of a single THAAD system. One THAAD battery will cost around US$1.3 billion or 1.49 trillion won. Funding for the purchase of additional THAAD systems is still undetermined.

Attacks from the Sea

Only a single THAAD battery is planned to be installed in South Korea. It is still unclear whether this will be enough to defend against North Korean submarine-launched ballistic missiles (SLBMs). As the THAAD radar only has a 120-degree field of view, it is possible for a North Korean submarine to travel outside of the range before firing. Based on analysis of North Korea’s test in August 2016, it is estimated that the SLBM would be able to travel over 1,000 kilometers on a minimum trajectory, making it possible for SLBMs to be launched further from the radar range. At least two THAAD batteries would be needed to cover all of North Korea’s sea and intercept possible SLBM attacks.


Positioning THAAD

The people of South Korea have held differing opinions on the decision of THAAD deployment. According to a Gallup Korea poll, after the announcement of THAAD deployment, 50% of the 1,004 respondents were in favor of the decision while 32% were against it. Over time, the number of supporters increased, as August 12, 2016 Gallup polls showed that 56% were in favor while 31% were opposed. Those who were in favor of THAAD mentioned national security and safety as their main considerations, while those who are against it were worried that the decision will negatively impact the country’s relationship with China and Russia. Some respondents also expressed a reluctance to be increasingly dependent upon the U.S. military.

Almost half of the respondents of the Gallup Korea poll in July supported the idea of hosting the THAAD battery in their neighborhood, compared to the 29% who said that they would be against it. However, there were challenges in deciding the location of THAAD. Areas with U.S. military bases were considered, such as Pyeongtaek, Wonju, Waegwan, and Gunsan. Eumseong County and Beolgyo, which are locations without U.S. bases, were also mentioned.

On July 22, it was announced that THAAD would be installed on a South Korean Air Force base in Seongju County by the end of 2017. Seongju County is located around 217 kilometers southeast of Seoul and its Air Force Base currently hosts a Hawk ground-to-air missile battery. The southern-central region was strategically chosen in order to protect Busan, Ulsan and Pohang from North Korean missile attacks. These are areas where South Korean and U.S. reinforcements and supplies would be located during an attack. However, positioning THAAD in Seongju (figure 4) would not protect Seoul. To defend Seoul, the current PAC defense system of the South Korean army will be upgraded. THAAD’s positioning in Seongju County was considered as a cost-saving measure since the THAAD could be installed alongside the existing Hawk battery without the need of purchasing any additional land.


The People’s Reaction to THAAD

The people of Seongju, however, did not approve of the decision. The inhabitants continually expressed their discontent citing  health concerns due to radiation and loss of land for the THAAD installation. The radiation claims have been disputed by the U.S., but experts disagree whether the safe distance from a THAAD radar is 100 meters or 3.6 kilometers. Some residents also expressed concerns that there would be an increase in loud bars, drunken soldiers, prostitution, and other illicit activities that have been prevalent around many of the U.S. military bases throughout South Korea.

Furthermore, there is the fear that the presence of THAAD will make Seongju a military target. 900 residents protested THAAD by shaving their heads in August  They also managed to collect 100,000 signatures for a petition against THAAD, which was sent to the White House.

The decision to choose Seongju as the location for the THAAD battery has also been considered as undemocratic. Local residents claimed that they had not been consulted until after the decision was made. The county governor also stated that he had only learned of the decision through media reports.

Due to the high number of protests, the South Korean government decided to change the location and considered three new alternatives: Mt. Kkachi in Sooryoon, Mt. Yeomsok in Geumsoo, and Mt. Dalma in Chojeon. Considering the operational effectiveness, resident health concerns, infrastructure, overall safety considerations, construction time and cost, and the required time for installation, it was finally decided that THAAD would be deployed on Mt. Dalma in Chojeon.

The new location of Mt. Dalma in Chojeon is currently used as a Lotte-owned golf course. It is located 18 kilometers north of Seongju county center and 300 meters higher than the South Korean Air Force base. The higher altitude and greater distance from residential areas would ease residents concerns of radiation.

However, there is currently opposition from the residents of Gimcheon. The residents along with city council members have conducted a demonstration in Seoul, claiming fear of radiation and that Gimcheon will become a military target. They also shaved their head in protest, mirroring what was done in Seongju. Demonstrators were accompanied by Won Buddhist, as the golf course is also located 500 meters from a sacred ground for their religion. In addition, the new location will be more expensive; the price of the golf course is over US$91 million or 100 billion won and parliamentary approval is needed for the budget.


Impact on the Region

North Korea’s Response

North Korea has viewed the decision to deploy THAAD as both a provocation and an act of aggression. Their response has been to continue missile development and invest in technologies that could bypass systems like THAAD.

Correspondingly, one day after the announcement of THAAD deployment, North Korea tested a Pukkuksong-1 (KN-11) SLBM. This was followed by three short-range missiles that were fired six days after the announcement and another two intermediate-range missiles in early August 2016. North Korea has also stated that they will retaliate with a “physical response.”

The continuous missile development by North Korea could be seen as tests for bypassing THAAD’s abilities, as it is possible to launch more missiles than a missile defense can intercept. So far, only one THAAD battery is planned to be deployed which could be a critical weakness. THAAD’s difficulty in intercepting missiles with irregular trajectories could also be used; in theory, North Korea’s medium-range Rodong missiles would be able to bypass THAAD as they have an irregular trajectory.

Recent analysis suggests that North Korea is developing a new submarine that would be larger than the previous GORAE-class experimental ballistic missile submarine. The improvement of SLBMs, could be considered another weakness of THAAD and would give a critical advantage to North Korea. In any case, North Korea have continued their nuclear development, conducting a fifth nuclear test in September 2016.

China’s Dilemma

Even before official THAAD discussions started, China expressed their opposition to the system. Although China is also against North Korean nuclear development, THAAD is seen as an attempt to obscure China’s strategic interests in the region.There are several reasons for this position.

First is China’s fear that THAAD could be used to intercept Chinese missiles. Both the U.S. and South Korea have denied this by stating that THAAD will only be used against North Korea. The THAAD battery will be placed in terminal mode, thus making it unable to detect Chinese intercontinental ballistic missiles (ICBMs). Furthermore, THAAD will be poorly positioned against Chinese intermediate-range missiles launched at South Korea or Japan. The location of THAAD will allow it to intercept missiles from Tonghua, which will follow the same trajectory as those from North Korea, but not missiles from Dengshahe, Laiwu and Hanchang.

However, a Pentagon report has shown that it is possible to change the system into forward-based mode in just eight hours. Once in this mode, the radar’s range would increase to 3,000 kilometers, making it possible to detect Chinese ICBMs heading towards the U.S. However, THAAD missiles would not be able to intercept Chinese ICBMs in their boost and mid-range phases, but the information could be transferred to the early warning radar at the Clear Air Force Station in Alaska. This would make it possible for a warhead to be tracked from a greater distance than as is possible currently. There is also the fact that two THAAD radars have already been stationed in Japan. An additional system in South Korea would better enable precise detection as the radar will be 1,000 kilometers closer to China. The installation of THAAD in South Korea could be seen to be an additional part of a larger U.S. missile defense system.

Another worry for China is the stronger relationship between South Korea, the U.S., and Japan. Through the deployment of THAAD, South Korea would have a long-term commitment with the U.S. strengthening its presence in Northeast Asia. China would have a lesser role in South Korea’s national security decision-making because of South Korea’s larger dependence on the U.S.



The deployment of THAAD in South Korea is a symbolic issue. The ROK has traditionally balanced its security interests between China and America. The inclusion of THAAD into South Korea’s missile defense would certainly tip the scales towards a ROK-U.S. alliance.

From a U.S. perspective, North Korea’s advancing nuclear program and the looming presidential election have made Pentagon officials push for THAAD as soon as possible. In their minds, cooperation between them, Japan and the U.S. would increase overall stability and security.

However, it is not that simple. THAAD’s effectiveness is debatable. Further, there is still no political consensus on the viability of THAAD and there is a distinct concern that its deployment may jeopardize relations with China. The People’s Party, (part of the opposition) are against THAAD deployment. As are the Minjoo Party which maintain that the decision to deploy THAAD was mainly done by prioritizing the US-ROK alliance over South Korea’s own interests. The fact that the ratification process was bypassed by the Park Geun Hye administration has also been a key point of contention. All of these factors may cancel THAAD, or, at the very least, delay THAAD deployment at a time when co-operation and stability is most needed.

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