What if someone offered to switch GDI with Aegis in Poland, in order to halt S300s for Iran? Doesn't make any sense? Read on. Russia and the United States are negotiating to solve some missile problems each side has. The United States wants to insure that Iran does not get S300 air defense systems (similar to the U.S. Patriot), and the Russians don't want the American GBI (Ground Based Interceptor) anti-missile system installed in Poland (to protect Europe from Iranian threats to use its ballistic missiles). Russian politicians have created a political monster by insisting that the ten GBI missiles would threaten the viability of the hundreds of Russian ballistic missiles aimed at Europe. This is absurd, but Russian politicians have painted themselves into a corner.
Moreover, aside from the money, there is no benefit to anyone to sell Iran S300 missile systems. So a compromise has been offered. The U.S. will withdraw the GBI, and replace it with the much cheaper, and "less threatening" (but just as scary to the Iranians), ground based Aegis system (which Israel wants, for the same reason, to intercept Iranian ballistic missiles.) In return, the Iranians would not get their S300s.
The American GBI (Ground Based Interceptor) system consists of a powerful radar system, and 12.7 ton ballistic missiles that delivers a 140 pound "kill vehicle" that will intercept a ballistic missile before it begins its descent into the atmosphere. The GBI kill vehicle can maneuver to destroy the incoming missile, while avoiding decoys. The U.S. is installing GBIs in Alaska and in California. More were on their way to Poland.
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.) The U.S. plans to install 5-10 GBIs a year over the next few years, until 30 are in service. 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.
The 18 U.S. Navy Aegis (radar) equipped ships have achieved an 83 percent success rate in using its SM-3 missiles to shoot down ballistic missiles during live test firings. The RIM-161A, also known as the Standard Missile 3 (or SM-3), 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 a three million dollar SM-3.
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 20 pound LEAP kill vehicle, which uses infrared sensors to close on the target and ram it. The Aegis system was designed to operate aboard 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). However, there is also a land based version that Israel is interested in buying. There is already one of these; the original development Aegis system built on land to debug and test Aegis before installing it on ships. Land based Aegis would cost about $50 million, plus the costs of the SM-3 missiles.