North Korea’s intercontinental ballistic missile (ICBM) launch this week underscored its steady push for technological progress and aggravated fears of a potential surprise liftoff for an attack, analysts said Thursday.

The North’s official Korean Central News Agency (KCNA) confirmed the country fired a Hwasong-18 ICBM on Wednesday, marking the second test-firing of the new solid-propellant missile following the first in April.

The missile flew 1,001.2 kilometers for 4,491 seconds at a maximum altitude of 6,648.4 km, before splashing into the East Sea, the KCNA reported, signaling Pyongyang is doubling down on the ICBM project despite international condemnation.

The apogee in the latest test was about double the maximum altitude recorded in the April test — an outcome thought to have resulted from a full-throttle rocket performance, which reflected its emerging confidence in the new missile, according to Chang Young-keun, head of the missile center at the Korea Research Institute for National Strategy.

In the previous test, the North is believed to have employed a method delaying the separation of the first stage of the three-stage rocket — and thus reducing its top speed and altitude — for testing purposes.

The method was apparently used to verify key functional elements of a nascent high-thrust solid-fuel rocket motor, on which Pyongyang carried out its first key ground test just last December.

But in this week’s test, the North used what it calls a “standard ballistic flight mode,” indicating that Pyongyang launched the missile without using the delayed stage separation method, Chang pointed out.

“As (its performance) was already checked in the previous test, the North appears to have desisted from using the delayed separation this time,” Chang told Yonhap News. “The first stage separation took place immediately after its combustion segment ended.”

The flight time of 74 minutes and 51 seconds — the longest for a North Korean long-range missile — signaled apparent headway in its acquisition of heat-resisting materials used for the throat of a rocket nozzle, observers noted.

Like the April test, the first stage was fired at a standard angle, while the second and third stages flew on a lofted trajectory.

If the missile had been fired on a normal trajectory, it would have flown more than 15,000 km, long enough to strike any part of the continental U.S., experts said.

A solid-fuel missile also poses a major security challenge to both South Korea and the U.S. given that it can blast off much faster than a liquid-fuel one, whose employment requires time-consuming pre-launch preparation procedures, including the injection of fuel.

The challenge will be compounded if the North uses hard-to-detect launch platforms, such as a road-mobile transporter, as well as train-borne and underwater launchers.

The North has been focusing on diversifying missile launch platforms to improve the survivability of missiles and avoid potential interception by the South’s missile defense and preemptive strike capabilities.

As for the motives behind this week’s launch, experts’ views varied.

Some highlighted the technological needs to sustain the North’s quest for a stable solid-fuel ICBM.

Others raised the possibility that the launch came in part to shore up its pride in the wake of a failed space rocket launch in late May and draw global attention during a North Atlantic Treaty Organization summit in Lithuania.

Source: Yonhap News Agency