China now has eight battalions of S-300PMU2 anti-aircraft missile systems, on the coast opposite Taiwan. These missiles have a range of 200 kilometers, and are positioned to fire on Taiwanese fighters as soon as they begin to cross the 180 kilometer wide Taiwan straits. This deployment dismayed most Taiwanese, although Taiwanese military leaders pointed out that they have Patriot anti-aircraft missiles deployed along the island coast. But the Patriot only has a range of 70 kilometers, and no one wants to talk about any electronic countermeasures Taiwan might have, that could neutralize the S-300 radars and missiles.
It gets worse. Two years ago, China began upgrading its anti-aircraft missiles, along its southern coast (facing Taiwan), from S-300PMU1 and S-300PMU2 systems to the S-300PMU3 (which has been renamed the S-400 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. There have been many upgrades since.
The missiles weigh 1.8 tons each and are 8.4 meters (26 feet) long and 51 cm (20) inches in diameter. The missiles have a range of some 200 kilometers (400 kilometers for one of the S-400 versions) and can hit targets as high as 32 kilometers (100,000 feet). The missile has a 145 kg (320 pound) warhead. The target acquisition radar has a range of 700 kilometers.
The S-400 has over five times the range of the U.S. Patriot, weighs twice as much 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-300/400 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. Taiwanese fighter pilots are not looking forward to being the first to experience that.