North Korea recently announced the it has formed a Taepodong 1 missile division. This is another way of saying that they are ready to attack American bases in Japan and Guam. This is not a big problem for American troops. That's because the Taepodong 1 missile accuracy is several hundred meters (the radius of the circle the missile warhead is likely to land in). The Taepodong 1 was first launched in1998, and went about 1,500 kilometers. Over the next decade, they got the range up to 3,000 kilometers.
Missiles of the Taepodong class are really too expensive to use with conventional warheads, but North Korea is unlikely to have a nuclear warhead that would work on the Taepodong 1. Nuclear warheads for ballistic missiles are very difficult to design and build. Unless they received technical assistance from someone who had already developed this technology, it will take a decade or more before North Korea has a workable nuclear warhead on their ballistic missiles. North Korea could arm the Taepodong 1 with a radiological warhead (explosives surrounded by radioactive material) that would disperse radioactive material over several square kilometers.
Five years ago, North Korea had 5-10 Taepodong 1 missiles. There are probably a dozen or more fit for service now. A major problem with the Taepodong missiles is that they require days, at least, to prepare for firing. North Korean missile launching sites are under constant surveillance by American and Japanese satellites. So a surprise attack is unlikely. North Korea used the Taepodong 1 design to develop an ICBM, the Taepodong 2, with a range of 6,000 kilometers. There are only a few of these, and their reliability is questionable.
Last year, American officials announced that sufficient anti-missile systems were being sent to Hawaii to deal with any potential North Korea success with their Taepodong missiles. The U.S. already has anti-missile systems in Hawaii (AEGIS SM-3 and THAAD/Terminal High Altitude Area Defense). Similar defenses are being established in Guam, and Japan has also built anti-missile system to defend themselves against North Korean ballistic missiles.
The anti-missile system already in Hawaii are some THAAD systems at the Pacific Missile Range Facility. Last year, the U.S. Army began forming the first of four THAAD batteries. This unit will be ready for combat next year. The other three batteries will be in service within four years. Two years ago, there was a successful test of THAAD (a SCUD type target was destroyed in flight) using a crew of soldiers for the first time, and not manufacturer technicians, to operate the system.
Each THAAD battery will have 24 missiles, three launchers and a fire control communications system. This will include an X-Band radar. The gear for each battery will cost $310 million. The 18 foot long THAAD missiles weigh 1,400 pounds. The range of THAAD is 200 kilometers, max altitude is 150 kilometers, and it is intended for short (like SCUD) or medium range (up to 2,000 kilometer) range ballistic missiles. Tweaks to the system are supposed to make it capable of handling something like the Taepodong 2. THAAD has been in development for two decades. Ultimately, the army would like to buy at least 18 launchers, 1,400 missiles, and 18 radars.
The navy has also modified its Standard anti-aircraft missile system to take down something like the Taepodong 2. 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 SM 3 missiles cost over three million dollars each. The SM 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 20 pound LEAP kill vehicle, which uses infrared sensors to close on the target and ram it. The AEGIS/SM-3 combination has had numerous successful tests, and recently shot down a low orbit satellite.
The SM-3 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.) There are several AEGIS equipped ships either near Hawaii, or close enough to reach the islands in less than a week.