Here's What You Need to Know: The U.S. Army has deployed Patriot and Terminal High Altitude Area Defense anti-air missile systems in South Korea in order to protect allied forces. But Patriot and THAAD are of limited use against a low- and fast-flying artillery rocket.

A multi-billion-dollar plan to move thousands of U.S. troops farther from the Korean demilitarized zone in order to get them out of firing range of North Korean artillery appears to have failed.

At the same time that the Americans are moving onto their new base, the North Koreans have been testing a longer-range rocket that can hit the facility.

For decades, many of the 30,000 U.S. troops in South Korea operated out of Yongsan Garrison in Seoul plus more than 150 other, smaller bases.

Seoul, a fast-growing city of 10 million, lies just 25 miles south of the DMZ, well within the range of many of North Korea’s 13,000 tube- and rocket-artillery pieces.

The new base, Camp Humphreys, lies 50 miles south of Seoul. To escape urban congestion and North Korean artillery, in 2004 the Pentagon brokered a deal with the South Korean government to expand Camp Humphreys—then a modest-size outpost—and concentrate U.S. troops and their families there.

The U.S. military aimed by 2020 to cut its installations in South Korea by nearly half to just 96 while also reducing their vulnerability. Until recently, the $11-billion Camp Humphreys lay beyond the range of most North Korean artillery. That changed starting in 2019.

Several times over the last few years Pyongyang has tested a new, “super-large” multiple-launch rocket with an estimated 370-millimeter diameter. The new rocket reportedly can strike targets as far away as 230 miles.

The new rocket system includes an eight-by-eight launcher vehicle fitted with four launch tubes, explained Dominguez Cespedes, an analyst with Jane’s. “The weapons, which both South Korea and Japan refer to as short-range ballistic missiles, seem to have small control surfaces on their noses: a feature seen on guided artillery rockets used in North Korea and other countries,” Cespedes added.

Pyongyang has been improving its heavy artillery in parallel with efforts to develop increasingly heavy, accurate and long-range ballistic missiles capable of carrying nuclear warheads. Three high-level summits since 2018 between U.S. President Donald Trump and North Korean dictator Kim Jong Un have done nothing to slow the hermit state’s arms build-up.

“Though the expanding range of North Korea’s ballistic missiles is concerning, a serious, credible threat to 25 million [Republic of Korea] citizens and approximately 150,000 U.S. citizens living in the [Greater Seoul Metropolitan Area] is also posed from its long-range artillery.” U.S. Army General Vincent Brooks, head of U.S. Forces Korea, told a U.S. Senate committee in March 2018.

“North Korea has deployed at least three artillery systems capable of ranging targets in the [Greater Seoul Metropolitan Area] with virtually no warning,” Brooks warned. The 170-millimeter Koksan gun is the most numerous. It can fire a distance of 37 miles. North Korea also deploys truck-mounted launchers that can fire a volley of as many as 22 240-millimeter rockets out to a range of 37 miles.

Pyongyang’s war-planners apparently intend directly to target Camp Humphreys in the event of war, retired U.S. Army colonel David Maxwell, a senior fellow at the Foundation for Defense of Democracies, told Army Times.

“If you pay attention to the North Korean propaganda, in July, they said they’ve been developing these weapons to be able to strike a ‘fat target’ in South Korea, and we assume that the ‘fat target’ is Camp Humphreys, as well as Osan Air Base, which is in close proximity,” Maxwell said back in 2019.

The U.S. Army has deployed Patriot and Terminal High Altitude Area Defense anti-air missile systems in South Korea in order to protect allied forces. The South Korean military has its own network of early-warning and air-defense systems.

But Patriot and THAAD are of limited use against a low- and fast-flying artillery rocket. The South Korean defense system also “may require a redesign to defeat North Korea’s newest weapons,” Shin Won-shik, a former vice-chairman of South Korea’s joint chiefs of staff, told Defense News. 

David Axe was Defense Editor of the National Interest. He is the author of the graphic novels  War Fix, War Is Boring and Machete Squad.

This first appeared earlier and is being reposted due to reader interest.

Image: Reuters.