June 23, 2011: South Korea announced that it has moved some of its ATACMS (Army Tactical Missile Systems) guided missiles close to the North Korean border. ATACMS is a 610mm rocket that fits in the same size container that normally holds six 227mm MLRS rockets. The ATACMS version in South Korean service has a range of 165 kilometers. That makes it capable of reaching many targets in North Korea, but not the North Korean capital (Pyongyang, which is 220 kilometers north of the DMZ). There is a version of ATACMS with a range of 300 kilometers, but South Korea does not have any. ATACMS is fired from the American MLRS rocket launcher. South Korea only has 220 ATACMS missiles. All of them have cluster bomb warheads. Half of them are unguided, and have a range of 128 kilometers. The other half have smaller warheads, GPS guidance and a range of 165 kilometers. This is apparently the version moved close to the border, in order to make the North Koreans nervous. South Korea originally bought ATACMS in 1998 to have a weapon that could go after distant North Korean artillery and large concentrations of tanks.
The current version of ATACMS equipped with a 227 kg (500 pound) high explosive warhead. The U.S. used over 700 ATACMS in Iraq and Afghanistan. These rockets use GPS guidance to hit targets up to 300 kilometers away. Sort of like the popular 500 pound JDAM smart bomb used by the air force, but not requiring an aircraft to deliver it.
When the U.S. Army first introduced its long range ATACMS rocket 24 years ago, it designed fancy warheads that distributed lots of smaller bomblets. While these worked, there was always a problem with some of the bomblets not self-destructing, and later going off when civilians, or American troops, came along. Not a popular weapon. Then, when a version, with GPS guidance and a single, 500 pound high explosive (or "unitary") warhead was introduced, it proved very popular. These rockets cost about a million dollars each. A 500 pound JDAM costs about $28,000, although you can add a few thousand dollars more to cover the expense of operating the jet bomber that delivered it.
While South Korea adheres to international treaties (barring missiles with a range of more than 300 kilometers, and warheads of more than half a ton), North Korea does not. As a result, North Korea has 600 Scud missiles, with ranges of up to 700 kilometers, and 200 Rodong missiles, with a range of 1,300 kilometers. There may be ten or more of the Taepodong-2 type in service, which have a range of over 3,000 kilometers. The North Korean missiles are not very reliable, but at least half of them are expected to function adequately in wartime, and hit their intended target. The Taepodong-2 types, however, have failed its last three tests, and North Korea is apparently having trouble developing the technology of getting multiple stage missiles to work. In the recent test, only the first stage worked, with the other two stages falling into the ocean. Because of the Taepodong-2 failure, Japan did not order its Aegis anti-missile systems to fire.