Japan recently confirmed its intention, announced in late 2013, to build two more Aegis equipped destroyers. The first of these will begin construction in 2015 and the second in 2016. The plan is to have both new ships in service by 2020. This will expand to eight the number of Japanese warships equipped with Aegis anti-missile systems. The first six Japanese Aegis ships with anti-missile capability were obtained by upgrading (at a cost of about $15 million per vessel) ships with the basic (anti-aircraft only) Aegis system. Japan wants anti-missile capability against potential North Korean or Chinese use of ballistic missiles.
Japan is quite pleased with its Aegis anti-missile system. In 2010, a Japanese Kongo class destroyer shot down a ballistic missile off Hawaii using its Aegis anti-missile system. That made three successful Aegis tests for Japan's Aegis equipped destroyers, out of four attempts. Encouraged by the success of Aegis and its acceptance by allied navies, the U.S. Navy continues developing new features. In 2013, it completed testing of the new Standard Missile 6 (SM-6) anti-aircraft missile.
Meanwhile, the navy has been continuing years of improvements in the Aegis radar and fire control system that controls SM-2, SM-6, and the smaller SM-3 anti-missile version. The SM-3 can destroy ballistic missiles and low earth-orbit satellites. The Aegis anti-missile system has had a success rate of over 80 percent in knocking down incoming ballistic missile warheads during test firings. Aegis equipped ships are now getting version 4.0 and the next major upgrade (5.0) will make the anti-missile capabilities a standard feature of Aegis software. New destroyers are having anti-missile Aegis software installed as standard equipment. Much of the anti-missile capability of the original Aegis anti-aircraft system came from upgrades to the Aegis software.
There are actually two models of the U.S. Navy Standard anti-aircraft missile that can hit missiles. 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-3 missile has a shorter range than the SM-2, which can destroy a warhead that is more than 200 kilometers up. 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 of what an SM-3 costs.