As the United States moves 8,000 marines from Okinawa to Guam, the air defenses of that American island are being improved. There will now be three different air defense systems. There will be a THAAD battery (24 missiles, three launchers and a fire control communications system). This will include an X-Band radar. The gear for each battery costs $310 million. The 18 foot long THAAD missiles weigh 1,400 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 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. China is about 3,000 kilometers from Guam. THAAD has been in development for two decades. 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 (20 kilometers) range. Patriot also fires anti-aircraft missiles, with a range of 70 kilometers.
Finally, there will be several batteries of SLAMRAAM. This system mounts four U.S. Air Force AMRAAM radar guided air-to-air missile on a hummer. A firing battery consists of one fire-control center, a radar (with a 75 kilometer range) and four to eight hummers carrying missiles. The missiles have an effective range of 25 kilometers, and can knock down cruise missiles, as well as helicopters. It was the need to knock down cruise missiles gives SLAMRAAM a similar mission to THAAD and Patriot; to knock down Chinese missiles. China is seen as the most likely threat to the many military facilities on the island.
Guam is about 7,000 kilometers west of Hawaii. The civilian population is 173,000 and military facilities include a major U.S. Air Force base, a port for U.S. naval forces in the central Pacific, and a base for SOCOM (Special Operations Command). The air force bases heavy bombers (B-52s and B-2s), fighters and tankers, plus Global Hawk UAVs. The navy has maritime patrol aircraft. The U.S. Coast Guard also has a base, as Guam is an American territory, and all residents are U.S. citizens. The army has several support facilities there. Aside from the military, the main economic activity is tourism, especially for visitors from East Asia.
Military facilities are being refurbished and expanded at great expense (over $8 billion), a project that will continue for another four years.