Kim Yo-jong touts hypersonic missile, but South Korean military calls it deception

Kim Yo-jong, head of the General Affairs Department of North Korea's ruling Workers' Party, touted a hypersonic missile (one flying at more than five times the speed of sound) launch by claiming it is 'impossible to intercept,' but South Korea's military countered that the claim was 'deception and exaggeration.' The crux of the disagreement is whether the missile has actually mastered the irregular flight maneuvers that make interception — shooting down an incoming missile — difficult.

However, it is hard to judge the success of the launch test based on North Korea's announcement alone. The most important characteristic of a hypersonic missile is that it must maintain a speed of Mach 5 or faster during the gliding phase, in which it repeatedly climbs and descends after launch. Department Director Kim emphasized that 'the missile's speed must be known,' yet did not disclose the gliding-phase speed. She claimed that 'when the wave-form flight trajectory method was applied, the enemies lost track of the target after the first pull-up point,' but did not provide the first and second apogee altitudes that would back this up.

A review of North Korea's public reports shows that the North has conducted roughly eight hypersonic missile test launches since September 2021. That said, South Korean military authorities did not recognize the four launches before 2024 as hypersonic missile tests, citing 'insufficient accuracy and range.'

Kim Yo-jong claimed that South Korea and Japan failed to track the flight trajectory of the intermediate-range strategic missile (hypersonic missile) that the North launched early on the 3rd. Military authorities countered that key data such as speed and apogee altitude were missing from North Korea's disclosure, calling it deception and exaggeration.