30/08/2017 8:13 PM AEST | Updated 01/09/2017 6:26 PM AEST

There's Something Odd About North Korea's Missile Test

North Korea’s missile test over Japan this week has puzzled experts, as the secretive state’s report of the launch flames questions about its true purpose.

The latest missile flew 1,680 miles before splashing down, much shorter and at a lower trajectory than that of an earlier launch.

Tuesday’s test was of the same Hwasong-12 missile Kim Jong Un has threatened to use on the US territory of Guam.

KCNA KCNA / Reuters
North Korean leader Kim Jong Un visits the Command of the Strategic Force of the Korean People's Army in this undated handout photo

Kim is quoted by North Korea’s news agency as saying: “The current ballistic rocket launching drill like a real war is the first step of the military operation of the [North Korean army] in the Pacific and a meaningful prelude to containing Guam.”

But the launch took it in another direction, over northern Japan’s Hokkaido and into the sea.

“It is not clear what new North Korea would have learned from this launch that is relevant to a long-range missile,” projectile expert David Wright of the Union of Concerned Scientists said.

KCNA KCNA / Reuters
A missile is launched during a long and medium-range ballistic rocket launch drill in this undated photo released by North Korea's Korean Central News Agency

The trajectory taken would not have been useful in simulating re-entry or heating of the missile, Wright wrote in a blog post.

And the shorter-than-expected range could point towards a mechanical failure.

“A more likely reason for a shorter range is a shorter burn time for the engines, either due to North Korea terminating the thrust early to reduce the range, or possibly due to a mechanical problem,” Wright said.

Supporting this theory is the fact reports of the launch by state-backed North Korean media lacked the usual tell-tale boasts of technical advances.

Kim Dong-yup, professor at the Institute for Far East Studies of Kyungnam University in Seoul, told Reuters that firing the missile from a densely populated area near Pyongyang and over Japan suggested North Korea was confident in the missile’s stability.

“I do not think North Korea factored in much military meaning behind yesterday’s missile launch, rather yesterday’s launch was all about North Korea being stubborn,” he said.

“At the same time, North Korea is hinting that there is room for negotiation if the US and South Korea end the joint military exercises.”

Extent of threat

KCNA KCNA / Reuters
A missile is launched during a long and medium-range ballistic rocket launch drill in this undated photo

The North’s inter-continental capabilities have thus far been calculated by international observers through analysis of so-called lofted launches.

Lofted launches propel missiles as high as possible at an almost vertical trajectory.

“To avoid firing long-range missiles into or over Japan, the North Koreans have been launching them nearly straight up instead,” Joshua Pollack, editor of the Washington-based Nonproliferation Review, told Reuters in July.

“They fly much higher into space that way, but come back down relatively close to their launch points.”

In July, one such launch by the North saw a missile travel higher in altitude than the International Space Station, over 3,500km high.

Click here for a zoomable version of this graphic

It was this launch which led experts to suggest that, were it to have been fired at a shallower angle, the missile could have reached the US east coast.

For a missile to become a threat, its nose cone has to be able to carry a nuclear warhead, and that warhead has to withstand the incredible stresses of re-entering the Earth’s atmosphere from space.

Missiles that land closer to home also make it easier for North Korea to collect and analyse data to improve the missile program, according to Pollack.

But it is still believed the state lacks crucial technology to construct reliable inter-continental ballistic missiles. 

If North Korea were to win support from outside enabling it to buy in rocket parts, Pollack said, “they could have an ICBM next month”.

On Wednesday, the United Nations condemned Tuesday’s “outrageous” test, which saw a ballistic missile fly directly over populated cities in Japan’s north - and its government warn citizens to “take cover”.