June 1, 2007: Russia has begun deploying another upgrade to its S300 air defense missile system, now renamed the S-400. The first battalion (four launchers and a radar) will be installed outside Moscow this Summer. Russia plans to buy up to 200 launchers (each with four missiles) by 2015, and phase out the older S-300 and S-200 systems. China, a major user of the S-300, will be a major export customer for the new system. South Korea is developing their own version of the S-400, via s special deal with Russia.

Originally called the S-300PMU3, it has been renamed the S400 because of the large number of improvements. The S-300/400 system is roughly equivalent to the U.S. Patriot system, and was originally known as the SA-10 to NATO, when the system first appeared in the early 1980s. S-300 missiles weigh 1.8 tons each and are 26 feet long and about 20 inches in diameter. The S-300 missiles have a range of some 200 kilometers (400 kilometers for the S-400) and can hit targets as high as 100,000 feet. The missile has a 320 pound warhead. The target acquisition radar has a range of 700 kilometers.

The S-400 has twice the range of the U.S. Patriot and claims the ability to detect stealthy aircraft. The S-400 also has an anti-missile capability, which is limited to shorter range (3,500 kilometers) ballistic missiles. That would mean a warhead coming in at about 5,000 meters a second (the longer the range of a ballistic missile, the higher its re-entry speed.)

The S-400 system actually has two missiles, one of them being a smaller, shorter range (120 kilometers) one. The S-300 has no combat experience, but U.S. intelligence believes that the tests these systems have undergone indicate it is a capable air defense weapon. Just how capable won't be known until it actually gets used in combat.