July 31, 2017: In July 2017 the U.S. Army carried out two more interception tests of its THAAD (Terminal High Altitude Area Defense) anti-missile system. Both tests (on the 11 ^th and 30 ^th ) were successful as were the other six such tests since 2010. There have been 28 test firings of THAAD since 1995 and 22 were successful. Many of the tests before 2005 did not involve attempting to actually intercept an incoming missile warhead. Many of the tests since 2008 were to verify that new features (like the ability to hit targets closer to the surface, and to share data with Patriot anti-missile systems) as well as verifying that the overall system worked. THAAD entered service in 2008 when the first THAAD anti-ballistic missile (ABM) battery was deployed. This followed a 2006 firing test that used regular army personnel and not developer technicians. In 2009 the second battery was formed. By 2012 there were five batteries with more on order by a growing list of export customers.

The most prominent foreign customer for THAAD is South Korea, which recently received a THAAD battery. While THAAD cannot intercept an ICBM warhead near its target, THAAD can intercept the ballistic missiles North Korea had been testing recently that could, in theory, be used as ICBMs. The two most recent North Korean tests of their Hwasong 14 missile landed less than a thousand kilometers distant and that flight profile is one THAAD could handle. The U.S., South Korea and Japan are discussing the usefulness of using current anti-missile systems (mainly Aegis and THAAD) available in or near South Korea to intercept further North Korean ballistic missile tests which are illegal and meant to be threatening. South Korea had the final say on this because North Korea had been threatening to invade again (as it did in 1950, as ordered by the Soviet Union). While North Korea would probably fail once more any new invasion would put much of South Korea’s population and GDP at risk because the capital, Seoul, is within artillery range of North Korea. This has always been a factor when considering how to deal with North Korean threats and North Korea knows it. But North Korea seems determined to develop nuclear weapons carried by ballistic missiles it can use against the United States, Japan and South Korea.

Each THAAD battery has at least 24 missiles and three launchers plus and a fire control communications system. This includes an X-Band radar. The gear for each battery costs $310 million. The 6.2 meter (18 foot long) THAAD missiles are 340mm in diameter and weigh 900 kg (1,980 pounds). This is about the same size as the Patriot anti-aircraft missile, but twice the weight of the anti-missile version of the Patriot.

The range of THAAD is over 200 kilometers, max altitude is 150 kilometers, and move at a speed of 2.8 kilometers a second. THAAD is intended for short (like SCUD) or medium range (up to 2,000 kilometer) range ballistic missiles. THAAD has been in development since the late 1980s. Originally the army planned to buy at least 18 launchers, 1,400 missiles, and 18 radars. That goal has been adjusted as the number of export customers increases. THAAD is a step up from the Patriot PAC-3 anti-missile (which is an anti-aircraft missile adapted to take out incoming missiles). The PAC-3 works, but it has limited (35 kilometers) range.

The navy has also modified its AEGIS software and Standard anti-aircraft missile system to operate like the PAC-3. This system, the RIM-161A, also known as the Standard Missile 3 (or SM-3), has a longer range than THAAD (over 500 kilometers) and max altitude of 160 kilometers. The Standard 3 is based on the Standard 2, and costs over three million dollars each. The Standard 3 has four stages. The first two stages boost the interceptor out of the atmosphere. The third stage fires twice to boost the interceptor farther beyond the earth's atmosphere. Prior to each motor firing it takes a GPS reading to correct course for approaching the target. The fourth stage is the nine kg (20 pound) LEAP kill vehicle, which uses infrared sensors to close on the target and ram it.

Thus the U.S. has three anti-missile systems available in and around Korea, although one of them currently only operates from warships (cruisers and destroyers that have been equipped with the special software that enables the AEGIS radar system to detect and track incoming ballistic missiles.) AEGIS can also be operated from land bases, and the manufacturer is offering such a system to export customers and already has several orders. In addition there is GBI, a system specifically designed for ICBMs and only stationed in North America.