For nearly tem years, the U.S. Navy has been working on adapting it's Aegis anti-aircraft system to defend against ballistic missiles. In 1997, a modified a Standard 2 missile shot down a SCUD type ballistic missile. The current Standard 2 anti-aircraft missile costs about $450,000 each. Each extended range missile is 21.5 feet long, 13.5 inches in diameter and weighs 1.3 tons. Range is 360 kilometers. The ABM version of the Standard 2 used a different warhead (with sensors and electronics suitable for hitting a fast moving ballistic missile.) These missiles cost about two million dollars each. However, this program ran into technical problems and was cancelled at the end of 2001. Testing a weapon is one thing, getting it to do that reliably in the field (or, in this case, on a warship) is often an insurmountable obstacle.
Meanwhile the navy had come up with a new missile. The Standard 3 is designed to reach out father (500 kilometers) and higher (160 kilometers) to hit larger missiles farther away. The Standard 3 is based on the failed anti-missile version of the Standard 2 and costs over three million dollars each. The Standard 3 has four stages. The first two stages 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 LEAP kill vehicle which uses infrared sensors to close on the target and ram it. The LEAP is a 20 pound warhead that destroys the targeted ballistic missile by hitting it. This system requires a modified Aegis radar system and there are only three ships that have had these changes made. The Standard 3 system has been tested and works, or at least it works against the test targets it has faced so far. It went three for three in tests during the last year. An improved version of the Standard 3 is in the works that will extend range first to 1,000 kilometers, then 1,500 kilometers. A new LEAP warhead will weigh 66 pounds and be more effective (because of better guidance and heavier weight.) The current thinking is that two or three Aegis cruisers equipped with Standard 3 missiles could shut down any attempts by North Korea, Iraq or Iran to use their current ballistic missiles. The Standard 3 does this by spotting and hitting the missiles while they are still rising up into the atmosphere. Systems like Patriot 3 or Arrow hit the missiles while they are coming down. At this point the missile is moving at several times the speed of sound and is actually a harder target to take out. The navy is buying 20 Standard 3 missiles to equip the three Aegis ships with the modified radar systems. These can be used in combat, if necessary, and are available for additional testing and development. The missiles are being produced at the rate of one a month.