Hyonhee Shin, Josh Smith

SEOUL (Reuters). South Korean military officials cast doubts Friday on North Korea’s “hypersonic missile test” fired last week. They said it seemed to be limited improvement over Pyongyang’s current ballistic missiles.

North Korea fired what it claimed was its second hypersonic weapon. This is usually defined by weapons reaching speeds greater than five times sound speed, or approximately 6,200 kilometers per hour (or 3,850 mph). They also have relatively slow trajectories which makes them harder to intercept and detect.

The missile’s warhead may have reached hypersonic speeds but that capability is also shared by other ballistic weapons. According to a South Korean military officer, Wednesday’s test failed to prove the range and maneuverability reported in the state media.

South Korea stated that the flight was less than North Korea’s claimed 700-kilometer (435 mile) and had less maneuverability than reported.

Wednesday’s warhead had a conical form than the North Korean hypersonic weapon test in September. It was glider-like.

The official stated that the missile was not a hypersonic glider nor a cruise missile. It is instead a missile equipped with a mobile warhead.

International analysts agree with this assessment. They noted that it appeared that the test involved a liquid-fuel missile equipped with a Manoeuvrable Reentry Vehicle, (MaRV), which was previously used by South Korea as well as the United States.

Jeffrey Lewis, a missile researcher at the James Martin Center for Nonproliferation Studies (CNS), stated on Twitter: “One of the problems with the hypersonic framing was that it incorrectly emphasizes speed while what really we should be discussing is manoeuvrability & accuracy.” So, yes, it’s hypersonic. More importantly it is a MaRV.

Although such missiles aren’t as powerful and range-expanding as North Korea’s intercontinental ballistic Missiles (ICBMs), experts believe that manoeuvrable weaponry can be used to evade missile defenses.

Japan and America jointly issued a statement Friday, pledging to strengthen their joint defense against hypersonic weapons.