North Korea launched its Hwasong-15 ICBM into the waters west of Japan at 3:17 am local time on Wednesday. Barely six minutes later, South Korean artillery, air force, and Navy sprang into action and began firing missiles into the waters off eastern Korea - yet another military show of force meant to intimidate the North into ceasing its missile strikes.

The retaliatory display was calibrated to target a spot in the waters off the Korean peninsula that was exactly as far away as Pyongsong, a town about 20 miles north of Pyongyang where the Hwasong 15 was reportedly launched. The distance was meant to signify that the South Korean military could destroy the North’s missile launchers if it chose to do so, the Wall Street Journal.

But while the precision strike probably impressed any bystanders who were watching, in reality, the South’s technology for detecting and responding to North Korean missile launches is still unreliable.

But detecting missile tests is an imperfect science, involving misses as well as hits. In a conflict situation, North Korea is likely to take more steps to conceal its movements, for instance by deploying decoy launchers, said Yang Uk, senior defense researcher at the Korea Defense and Security Forum, a Seoul think tank.

 

In such a scenario, the likelihood falls that South Korean, U.S. or Japanese forces would pinpoint the exact launch site, Mr. Yang said. Still, he viewed the South’s response to the missile test as a success, especially considering the short time the military needed to return fire.

 

A spokesman for the U.S.-led U.N. Command in Korea said no U.S. or other forces participated in the response.

 

“What we saw Wednesday was an active response to a North Korean missile launch that South Korea calls its ‘kill chain’ system’,” Mr. Yang said. The kill chain is part of a larger defense system designed to pre-emptively strike the North’s missile systems in the case of a nuclear attack.

 

South Korea this year installed a U.S.-operated Terminal High-Altitude Area Defense antimissile battery that can shoot down short- and medium-range missiles, complementing its Patriot PAC-2 antiballistic missile system.

 

The new battery has a longer-range, but it can’t cover the whole country.

A retired senior South Korean military official said that the South lacks a military satellite that can watch the North, although US and Japanese satellites share images with South Korean officials in real time.

Meanwhile, analysts said North Korean officials install devices onto missiles that generate signals and send them to ground-based control towers. The South has a way to tap into these signals and track the missiles, they said.

But in a real missile launch targeting a South Korean, Japanese or U.S. city, the North Koreans may choose not to install them, said Jo Dong-joon, deputy director of the Institute for Peace and Unification Studies at Seoul National University. This means that the South might have no way to track a hostile missile, Mr. Jo said.

The retired military official also noted that the South has a network of human intelligence in the North that may have tipped off Seoul officials about this week’s launch. He declined to give further details, citing security concerns.

Details on the South’s spy network in the North remain murky, but local media have reported in recent months that the South has lost most of its human network in North Korea in recent years.