Romania, one of the East European nations that eagerly joined NATO after the Cold War ended, has ordered eight Patriot air missile batteries from the U.S. manufacturer for $950 million each. This is to provide more protection from potential Russian aggression.
A Patriot battery is manned by about a hundred troops and contains a radar plus four launchers. A battery can fire two types of Patriot missile. The $4 million PAC 3 missile is smaller than the cheaper anti-aircraft version (PAC 2), thus a Patriot launcher can hold sixteen PAC 3 missiles, versus four PAC 2s. A PAC 2 missile weighs about a ton, a PAC 3 weighs about a third of that. The PAC 3 has a shorter range (about 20 kilometers) versus 96 kilometers for the anti-aircraft version. While each Patriot launcher, loaded with PAC 3 missiles, can only defend against ballistic missiles approaching within 20 kilometers, the Patriot radar can detect targets out to a hundred kilometers. Two PAC 3 missiles are fired at each incoming ballistic missile, to increase the probability of a hit. The PAC 3 missile has its own radar, and uses it to track the incoming warhead, and execute a collision course.
It’s unclear if Romania is getting Patriot with the PAC 3 capability but just with PAC 2 Patriot would render any Russian threat less viable. In addition since Russia became more threatening in 2014 Romania has increased defense spending and allowed the U.S. to move in more air defense weapons. For example, in 2016 the only land-based Aegis anti-aircraft/missile system in existence (in New Jersey) was taken apart and sent to Romania where it has been be put back together, tested and became operational in May 2016 as an anti-missile system. The U.S. is building two more ground-based Aegis systems; one in Poland and one in Hawaii. All three, including new Aegis components for two of them and needed missiles (24 per location) and launching hardware for all of them will cost $2.3 billion. That’s nearly $800 million per system.
The U.S. also wanted to put silos for the GBI (Ground Based Interceptors) in Romania but Russia was very much against this as they saw it as diluting the intimidation effect of their ICBM force. The GBI project was put on hold but may be revived. The GBI is a 12.7 ton ballistic missile that delivers a 64 kg (140 pound) "kill vehicle" that will intercept a ballistic missile before it begins its descent into the atmosphere. The GBI kill vehicle attempts to destroy the incoming missile, while avoiding decoys. The U.S. already has GBIs deployed in Alaska and California. The GBI can receive target information from a variety of source, mainly a large X-band radar and space based sensors (that can detect ballistic missiles during their initial launch.) Each GBI costs over $100 million (up to several hundred million dollars, depending on how many are built and how you allocated development costs.) The GBI can intercept ballistic missiles launched from as far away as 5,000 kilometers.
Since the land based Aegis in Romania will belong to the United States it was decided to use the development version of Aegis for this since it was always land based and was still operational. With so many Aegis systems at sea, development work can be done on one of those. When Aegis went live in Romania Russia protested and threatened Romania. For the Romanians, annoying the Russians is a bonus for a system that is there mainly to protect Europe from Iranian missiles.
Aegis has achieved an 83 percent success rate during live test firings. To knock down ballistic missiles, Aegis uses two similar models of the U.S. Navy Standard anti-aircraft missile, in addition to a modified version of the Aegis radar system, which can now track incoming ballistic missiles. The anti-missile missile is the RIM-161A, also known as the Standard Missile 3 (or SM-3). It has a range of over 500 kilometers and max altitude of over 160 kilometers. The Standard 3 is based on the anti-missile version of the Standard 2 (SM-2 Block IV). This SM-2 missile turned out to be effective against ballistic missile warheads that are closer to their target. One test saw a SM-2 Block IV missile destroy a warhead that was only 19 kilometers up. An SM-3 missile can destroy a warhead that is more than 200 kilometers up. But the SM-3 is only good for anti-missile work, while the SM-2 Block IV can be used against both ballistic missiles and aircraft. The SM-2 Block IV also costs less than half what an SM-3 costs. The SM-3 has four stages. The first two 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.