After months of intense pressure, and years of nagging, the U.S. has agreed to reduce restrictions (imposed as part of a mutual defense arrangement) on the range of South Korean developed ballistic missiles. Under the new rules max missile range goes from 300 to 800 kilometers. Max payload for cruise missiles (and UAVs in general) goes from half a ton to 2.5 tons. In the end, the South Koreans told the United States that if the agreement was not changed South Korea was ready to just go ahead with building longer range missiles, to better deter China as well as North Korea.
For the last 30 years the United States has been discouraging South Korea from developing long-range ballistic and cruise missiles. This was done to try and halt an arms race with North Korea but the north never took the hint. Meanwhile, the U.S. assured the south that America would show up for the fight if the north attacked. Despite American opposition, South Korea began developing, but not mass-producing, ballistic missiles in the 1970s. South Korea certainly has the technical expertise and manufacturing capability to produce a more modern ballistic missile with a range of 300 kilometers or more. Public opinion in the south has long called for that limit to be broken, in order to make all of North Korea vulnerable to ballistic missile attack from the south. This change also sends a message to China that South Korea is not to be messed with.
The South Korean military wants to spend over $2 billion on missiles during the next five years. This is in an effort to quickly weaken the North Korean artillery and missile forces in any future war. The South Korean plan is to purchase and deploy over a thousand new ballistic and cruise missiles. These would be aimed at specific North Korean missile launchers and artillery positions. In the event of a war, the South Korean missiles would be quickly launched and every North Korean missile or artillery weapon eliminated would mean less destruction in South Korean territory. The North Korean plan had always been to start any future war with an enormous bombardment by shells, rockets, and missiles. Most would be aimed at the South Korean capital, and largest city, Seoul.
Nearly all the $2 billion will be spent on missiles made in South Korea. In the last year the government has revealed the existence of more of these locally developed missiles. Earlier this year South Korea made public the fact that it had a new cruise missile (apparently the Hyunmoo 3) and ballistic missile ready for service. South Korea is usually secretive about its battlefield missiles. Three years ago South Korean media reported that a new cruise missile, with a range of 1,000 kilometers, had secretly entered production in 2008. The missile, called Hyunmoo 3, has since been superseded by the Hyunmoo 3C missile, which has a range of 1,500 kilometers and is being deployed along the North Korean border, aimed at ballistic missiles, nuclear weapons, and other strategic targets to the north.
Despite the U.S. refusal to help, South Korea developed a 180 kilometer range ballistic missile (Hyunmoo 1) and a 300 kilometer one (Hyunmoo 2) in the 1980s. Both are about 13 meters (40 feet) long and weigh 4-5 tons. Both of these were based on the design of the U.S. Nike-Hercules anti-aircraft missile, which South Korea used for many years.
Cruise missiles are simpler technology, and apparently the Hyunmoo 3 is made entirely with South Korean developed components. Like the Tomahawk, Hyunmoo 3 appears to be about 6 meters (19 feet) long, weighs 1.5 tons, has a half ton warhead, and is launched from hidden (in the hills facing North Korea), and probably fortified, containers. North Korea has about 600 ballistic missiles aimed at South Korea.
The longer range of the Hyunmoo 3C enables it to hit any target in North Korea and is apparently intended to knock out transportation and supply targets deep inside North Korea. With a range of 1,500 kilometers the missile could also hit targets in China and Russia.
Last year South Korea moved some of its U.S. built 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 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 others 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.