North Korea’s fiery spy-satellite test shows more than failure

Pyongyang seems intent on developing a higher-thrust engine that is powerful enough to carry multiple satellites on a single rocket, weapons analysts say.

The Kim regime’s unsuccessful first go-round with advanced rocket-propellant technology shows how the country still has sizable technological gaps, despite major weapons advances elsewhere and presumed assistance from Russia.

Expectations for North Korea’s satellite launch have remained elevated after Kim traveled to Russia in September to meet President Vladimir Putin, who promised to help with North Korea’s space endeavors. Since then, South Korean officials have said many Russian technicians had entered North Korea and that several Kim regime engine tests were detected before the launch on Monday.

In the past, North Korea appeared to have relied on hydrogen as fuel and so-called “red fuming nitric acid" as the oxidizer necessary for rocket combustion. On Monday, North Korea attributed the failure to a newly developed engine reliant on petroleum and liquid oxygen.

It isn’t unusual for satellite launches to fail, especially for countries like North Korea that have little experience launching space rockets, weapons analysts say, and even help from Russia may not have been enough in testing a new method.

That is technology embraced by the world’s space powers, such as the U.S., Russia and China, said Yang Uk, a military expert at the Asan Institute for Policy Studies in Seoul. SpaceX’s Falcon 9, for instance, uses kerosene fuel, a petroleum product, and liquid oxygen for its propellants.

“Changing the oxidizer isn’t necessarily complicated technology," Yang said. “But if you’ve never developed or used it, you need someone’s advice and that was likely Russia."

Nations with advanced space programs have also moved away from using hydrogen, due to the toxic substances released as fuel burns, the lengthy fueling time and the higher rates of explosion, said Hong Min, head of North Korean research at the Korea Institute for National Unification, a state-funded think tank in Seoul.

North Korea’s long-range missiles overlap in technology with the country’s satellites, which is a reason why such activity is barred by the United Nations Security Council. But longer term, the new propellants could mean Pyongyang’s missiles experience fewer test failures due to hydrogen fuel that ignites easily.

“Russia, China and even South Korea are using the same fuel, and North Korea may have taken Russia’s advice in shifting to the safer global option," Hong said. “Eventually it could also help advance North Korea’s ICBM technology."

Monday’s satellite launch came shortly after the leaders of China, Japan and South Korea met in Seoul for their first trilateral meeting since 2019. The rocket was launched from Sohae Satellite Launching Station on North Korea’s west coast but exploded during an early stage of the flight, according to Pyongyang’s state media. South Korea’s military said it detected debris scattered over North Korean waters a few minutes after liftoff.

North Korea placed its first spy satellite into orbit last November, following two failed liftoffs. In January, Kim vowed to launch three more reconnaissance satellites this year as he called for an “overwhelming war response capability" to deter the U.S.

Pyongyang received assistance from Moscow for its November launch, with Russia analyzing the data of previous launches for the Kim regime, South Korea’s spy agency said. In February, South Korea’s defense minister said the North Korean satellite appeared to be orbiting Earth without activity, despite Pyongyang’s claims that its satellite was functioning and capturing images from space.

Footage filmed on Monday by an observation device on a South Korean patrol vessel showed what appeared to be an explosion in the sky followed by flashes. A video by Japanese broadcaster NHK showed a fiery ball flying into the sky and then bursting into flames near the border between China and North Korea. Japanese officials had briefly issued an emergency warning for residents of the island of Okinawa to take cover.

Write to Dasl Yoon at dasl.yoon@wsj.com