North Korea’s nuclear claims hint at innovation, raising alarms

North Korea says this nuclear warhead is smaller than anything it has produced before. If it is real, it could potentially fit on missiles that could hit South Korea and Japan.

The warhead is also portrayed as being able to be mounted on a variety of missiles, which could give North Korea more production options.

New short-range ballistic missiles, which the small warhead is designed for, are hallmarks of North Korean leader Kim Jong Un’s effort to modernise his missile fleet.

Kim Jong Un and his daughter, Kim Ju Ae, took centre stage at a military parade in Pyongyang that featured North Korea’s latest nuclear missile technology.

— in pictures https://t.co/A1hMIhtKjO pic.twitter.com/J7BusIdyvY

— Al Jazeera English (@AJEnglish) February 9, 2023

In a critical upgrade, North Korea uses solid fuel instead of liquid fuel to power the missiles, which makes them easier to transport, faster to launch and harder to intercept.

North Korea also claims a smaller warhead will give it new ways to carry out nuclear strikes — on a cruise missile, or on what it calls an “underwater nuclear drone.”

Though much of the information that comes out of Pyongyang is propaganda, there is no doubt that North Korea has achieved major upgrades to its arsenal. (Schematics of North Korea’s Hwasan-31 missile via New York Times)

For decades, Washington, Seoul and their allies have tried both negotiations and sanctions to roll back North Korea’s nuclear ambitions and prevent technological advances like these.

Those efforts failed. The world is now seeing what comes next: a bigger, more dangerous nuclear arsenal that poses a greater threat to the United States and its allies in Northeast Asia.

It’s unclear whether or not the warheads in the photo were real. North Korea has a track record of showing mock-ups of weapons still under development for the sake of propaganda. Still, Kim has set bold goals for an arms buildup, pouring resources into weapons development.

Schematics comparing the KK-23 to the Scud-C. (New York Times)

There is no doubt that the North has achieved major upgrades to its arsenal, including solid-fuel ballistic missiles that can also make midair maneuvers. It is also developing cruise missiles, submarine-launched missiles and underwater drones that it says could be nuclear-armed. All these efforts are aimed at making its nuclear attacks more effective.

The launch of two ballistic missiles Thursday was the latest demonstration of Kim’s dogged determination to expand the North’s military capabilities.

Smaller warheads that target regional adversaries

Since his failed diplomacy with President Donald Trump, Kim has urged his country to develop “nuclear weapons smaller, lighter and tactical” to target South Korea, Japan and US military bases in the region. These short-range weapons do not threaten the continental United States, but they could boost Kim’s leverage against Washington by placing American allies under nuclear threat.

Although North Korea has conducted six underground nuclear tests, it has never been clear whether it has successfully developed smaller warheads. The photo released in March was the first concrete indication that it may have succeeded.

Visual timeline of missiles tested since 2016. (New York Times)

So far, North Korea has released photos of three nuclear devices, and the latest one — dubbed Hwasan-31, or “Volcano-31” — is by far the smallest.

Although these are propaganda photos, South Korea in February acknowledged, in a defense white paper, the North had achieved “a significant level of miniaturisation” in its nuclear weapons.

The significant shift took only a few years. Kim had suspended testing missiles and nuclear devices before his 2018 summit with Trump. He resumed missile tests in 2019 as the talks failed to bring about benefits he had sought, especially the easing of sanctions. Since then North Korea has been testing short-range ballistic missiles that could serve as delivery systems for these small nuclear warheads at a fast clip.

The resumption of missile tests featured three new short-range ballistic missiles, known to the outside world as KN-23, KN-24 and KN-25. They can be mounted with nuclear warheads and reach South Korea, Japan and US military bases in the region in a matter of minutes. All these characteristics make them more dangerous.

Solid-fuel missiles that are harder to intercept

North Korea’s new series of short-range ballistic missiles are all powered by solid fuel. This makes them easier to hide and transport and faster to launch than older missiles that rely on liquid fuel, which is highly corrosive and unstable.

Compared to liquid-fuel missiles, which could take hours to load prior to launch, solid-fuel missiles can be quickly rolled out of mountain tunnels ready for launch in a short time. This and their shorter burn time make it harder to detect where the missiles are and when they would be launched, thus leaving less time for missile defense systems to react. Their midair maneuverability also makes it harder to shoot them down. That is forcing the United States and its allies to spend billions of dollars to upgrade their defenses.

Map showing range of missiles. (New York Times)

“Solid-propelled missiles have shorter burn time than liquid ones. This makes the window of detection, where infrared sensors could see the hot rocket motor working, smaller,” said Markus Schiller, a rocket analyst from the German space technology consulting firm ST Analytics.

North Korea plans to retire its old Scud and Rodong liquid-fuel short- and medium-range ballistic missiles, replacing them with a new fleet of solid-fuel missiles, according to the South Korean Defense Ministry.

In December, the North tested a new high-thrust solid-fuel rocket engine, indicating that it is switching its longer-range missiles to solid fuel as well. On April 13, it tested its first solid-fuel ICBM, Hwasong-18, for the first time. Analysts warned that there would be more Hwasong-18 tests as the North tries to perfect the system.

The remaining technical hurdles

Many of North Korea’s claims about its weapons capabilities, such as those concerning nuclear underwater drones and hypersonic missiles, are exaggerated, according to the South Korean military. Some of its new weapons, such as the Hwasong-18 ICBM, are still in developmental stages.

Missiles launched from vehicles in North Korea since 2019. (New York Times)

North Korea has so far launched all its ICBMs at deliberately steep angles, so that they fly extremely high into space but fall into waters between the North and Japan. It has yet to prove that its ICBMs can actually cover an intercontinental range.

“Although there is a gap between the North’s claims and our assessment, we cannot dismiss them,” South Korean Defense Minister Lee Jong-sup said in April, referring to the North’s claim to have standardised a small and light nuclear warhead for its various missiles. If North Korea conducts another nuclear test, its seventh, it may be to show that its new and smaller Hwasan-31 warhead works.

“It will not be easy to say that the North has developed a small and light nuclear warhead until it successfully tests it,” Lee told South Korea’s legislature.