Now the North Koreans can fire missiles before America’s eyes in the skies have had time to detect them on the launch pad.

That’s the message the North’s leader, Kim Jong-un, wants to convey by ordering the launch of a Hwasong-18 intercontinental ballistic missile that plopped into the waters off North Korea’s northeast coast.

The North’s Korean Central News Agency boasted Friday of the success of the launch that Mr. Kim witnessed with his tween-age daughter, Ju-ae, who’s been at his side during parades and previous launches.

It was the first time North Korea has blasted off a missile powered by solid fuel that has the advantage of being inside the missile before it’s moved from hiding. That’s more dangerous, experts warn, than liquid fuel that’s pumped into a missile on the launch pad, adding time to track and shoot it down possibly before it’s fired.

KCNA described the launch in a dispatch disseminated in  English to show off North Korea’s potential for inflicting death and destruction while America and South Korea are conducting military exercises against the North.

“The aim of the test-fire was to confirm the performance of the high-thrust solid-fuel engines for multi-stage missiles,” KCNA said. The test, it said, proved “the reliability of the stage-jettisoning technology and various functional control systems” as well as “the military feasibility of the new strategic weapon system.” 

The dispatch was careful to allay the fears of Japanese that the missile might land close to Japan — if not on Japanese soil.

“In consideration of the security of the neighboring countries and the safety of the multi-stage-separation of the missile during its flight.” KCNA said, “the test fire was conducted in the way of applying the standard trajectory flying mode to its first stage and the vertical mode to the second and third stages.”

While the Japanese were responding with alarm to word of the launch, KCNA said the second stage of the missile flew straight up 1,000 kilometers above the earth, falling into the sea 350 kilometers off the North’s northeast coast.

Laden with colorful language for the benefit of foreign readers, KCNA reported the missile “began to soar into the sky with fierce flames at its tail, making a thunderous roar.”

The missile, KCNA said, was “a great entity fully representing the irresistible might of the DPRK,” the Democratic People’s Republic of Korea. It “confirmed that all the parameters of the new strategic weapon system fully met the requirements in terms of accuracy … as a powerful strategic attack.” 

American and South Korean military analysts have long known that North Korea was developing solid fuel as a propellant for missiles. There was no doubt the latest launch, as described by KCNA, represented a step up in the dangers. 

“Solid-fuel rockets consist of a fuel and oxidizer that are pre-mixed in a solid form,” an explainer by the National Air and Space Museum in Washington said. “This fuel system is simpler, safer, and cheaper — but less efficient — than that of a liquid-fuel rocket.” 

The test, though, raised the question of what Mr. Kim really hopes to achieve by placing such stress on his nuclear and missile program while his people suffer increasing economic difficulties. One view is that eventually he will look for negotiations in which the North is recognized as a nuclear power. 

Right now, there’s no sign of dialogue. North Korea did not respond to American and South Korean denunciations of the missile launch. For the past week, North Korea’s side has not picked up the phone on a “hotline” at the truce village of Panmunjom on the North-South line. Previously North and South Korean officers were talking briefly twice a day.