July 8, 2017: Japan has decided that it does not need the more expensive THAAD anti-missile system and is instead negotiating to buy two land base Aegis anti-aircraft/missile systems equipped with the SM-3A anti-missile missile. These two systems would be sufficient to protect the Japanese main islands and Japan is confident they would work. In part that’s because Japan also has six Aegis equipped destroyers equipped with SM-3 missiles. In addition Japan has 24 Patriot antiaircraft missile batteries that can also fire the PAC-3 anti-missile missile. The PAC-3 has one drawback, it only has an effective range of 30 kilometers against incoming missiles.

The first Aegis Ashore system became operational in 2015 in East Europe and appears to be as reliable as the original ship-based systems. This was what was expected because the East European Aegis had never been to sea. In early 2014 the only land-based Aegis system in existence (in New Jersey) was taken apart, packed into 60 large (40 foot) shipping containers and sent to Romania where it was put back together and in 2015 was an operational anti-missile system. The U.S. already had orders for 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 came out costing $767 million each. The Japanese Aegis Ashore installations will cost closer to $355 million each. Now Japan joins the growing list of customers.

Back in 2010 Romania agreed to base American anti-missile systems on its territory. It was assumed this would include a land based Aegis system. At that time Israel also expressed an interest in buying a land based version Aegis, but that deal fell through. Since the land based Aegis in Romania will belong to the United States it was decided to use the land based development version of AEGIS for this since this New Jersey facility was still operational. With so many ships equipped with Aegis, development work can be done using one of those from now on.

The U.S. has long sought to put anti-missile systems in Eastern Europe to protect against ballistic missile attacks from Iran. Russia has opposed this and sees it as a subterfuge to weaken the effect of Russian ballistic missiles attacking European targets. Most Europeans don’t know what to make of that, but East European countries (like Romania) that spent 1945-89 as involuntary Russian vassal (or “satellite”) states, do see a need for protection from Russian missiles.

So far, Aegis has achieved an 83 percent success rate during live test firings. So now many countries want Aegis ABM (Anti-Ballistic Missile) ships for protection from local ballistic missile threats. The Aegis system was designed to operate aboard warships. These are usually cruisers and destroyers that have been equipped with the special software that enables the AEGIS radar system to detect and track incoming ballistic missiles. Currently, the U.S. Navy has about 40 ships with the Aegis anti-missile system. There are over 100 American and foreign warships equipped with Aegis, but less than half of them had the software mods and anti-missile missiles that enable them to shoot down ballistic missiles and low-orbit satellites. Converting an Aegis ship to Aegis ABM costs about $20 million, mainly for new software and a few new hardware items. This is seen as a safe investment and the U.S. expects to see most Aegis equipped ships to be upgraded to ABM versions in the 2020s.

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.