North Korean Missiles Just Keep Getting Better 

In the absence of any concrete nuclear deal with the United States, North Korean leader Kim Jong Un continues to assemble, piece by piece, a sophisticated nuclear weapons arsenal and the capacity to deliver those weapons on neighboring countries.

With his diplomatic opening toward North Korea stalled, U.S. President Donald Trump has insisted that he has at least managed to halt the North’s pattern of testing long- and medium-range missiles capable of visiting serious damage on U.S. allies in Northeast Asia. But this week, Kim appeared to snuff out the last vestige of progress for the American leader, with the test of a submarine-launched ballistic missile.

The timing of the launch could hardly be more embarrassing to Washington. U.S. and North Korean representatives are preparing to meet in Sweden this weekend for long-delayed working-level talks, and this week’s test underscores that North Korea’s military capabilities continue to advance in the shadow of a so far fruitless diplomatic initiative. “It’s a reality check for the Americans,” said Hans Kristensen, who directs the Nuclear Information Project at the Federation of American Scientists.

Two years ago, Trump threatened to go to war with North Korea over its advancements in missile technology, including intercontinental ballistic missiles that could reach the United States. This week’s test of a medium-range missile lacks the provocative range of those tests but uses technology that could be applied toward future advances in North Korean missile technology.

Speaking to reporters on Thursday, Trump abandoned his typical dismissal of North Korean missile tests as insignificant. Asked whether the North Korean test this week had gone too far, Trump hedged: “We’ll see.”

“They want to talk, and we’ll be talking to them soon,” Trump said.

Basic hurdles remain to be cleared in those talks. Most importantly, the two sides still have not agreed on a shared definition of the “denuclearization” of the Korean Peninsula, the key term of the statement signed by Trump and Kim in Singapore last year.

Against the background of that impasse, the U.S. negotiating team is heading to Stockholm for its rendezvous with North Korean diplomats with a less hard-line negotiating position than in the past. According to a report in Vox this week, Washington is prepared to suspend U.N. sanctions “on Pyongyang’s textile and coal exports for 36 months in exchange for the verifiable closure of the Yongbyon nuclear facility and another measure, most likely the end of North Korea’s uranium enrichment.”

Whether Pyongyang would be amenable to such a move is highly unclear, but it would provide the two sides a bit of maneuvering room to hammer out a more substantive agreement and give the North an infusion of cash from textile and coal exports.

It would also allow North Korea to continue the steady improvement of its missile program, as evidenced by the submarine-launched missile test this week. That missile, the Pukguksong-3, won’t be deployed on North Korean submarines for years, but that hardly diminishes its significance to Pyongyang. The two-stage, solid-fuel missile is a major technical achievement for North Korean weapons engineers, demonstrating their improving knowledge of the solid-fuel rocket technology that will take the North’s missile program to the next level.

As North Korean missile capabilities continue to mature, Pyongyang will likely shift from using mostly liquid-fuel, long-range missiles to ones that use solid-fuel rocket motors. The Pukguksong-3 represents a key milestone on that road. It is the longest-range solid-fuel missile ever tested by North Korea, with a likely range of around 2,000 kilometers that puts all of Japan in its crosshairs.

The long-range missiles tested by North Korea in 2017 that brought the country to the brink of war with the United States were all liquid-fueled, but with Kim having placed a moratorium on the testing of those weapons, his attention has shifted toward testing shorter-range, more technically sophisticated missiles.

This summer, North Korea carried out a series of tests of the KN-23, a short-range weapon that appears to be a derivative of an advanced Russian missile that also uses a solid-fuel engine. Now, the solid-fuel engine has reappeared, this time in a submarine-launched missile.

Taken together, the missiles illustrate North Korea’s pursuit of weapons that are capable of eluding destruction by the U.S. military in the event of war and with the capability of penetrating missile defense systems in the region. The KN-23 has features that make it difficult to shoot down with missile defense systems. The Pukguksong-3, once deployed to sea, will be a formidable challenge to detect in the event of war.

To be sure, the missile tested this week is a long way from operational deployment. North Korea probably lacks a submarine on which to deploy the missile and probably won’t have a sufficient number of subs to keep the missile constantly at sea for many years. The missile expert Michael Elleman estimates that North Korea would need at least three and as many as five subs to keep the missile constantly at sea.

But developing a sea-based nuclear deterrent represents a clear priority for Pyongyang. In July, North Korean state media published photographs of Kim inspecting a submarine under construction that appeared designed to carry ballistic missiles. (This week’s test was most likely carried out using an underwater barge.)

The lessons from this week’s missile test will now be taken and applied to the country’s land-based missile systems. The development trajectory of North Korean missile forces will likely involve taking the solid-fuel engines tested this week and scaling them up for use in larger, longer-range missiles, probably deployed on land.

“If you’re thinking about militarily useful missiles, that’s what you want,” said David Wright, a senior scientist and the co-director of the global security program at the Union of Concerned Scientists.