On October 14, 2026, North Korea’s military conducted underwater launches of cruise missiles for the first time in nearly three years — two types at once: one emerged from a vertical launch tube, the other from a torpedo tube. South Korea’s Joint Chiefs of Staff recorded the launches and confirmed: the firing platform was a submarine. KCNA did not name it, but experts identified the boat in the released photographs as that very submarine — Hero Kim Kun Ok, hull number 841, ceremonially launched in September 2023 and never once seen at sea since. The War Zone stated the obvious: this was the submarine’s first publicly documented appearance at sea, and it was already firing missiles.
By itself, the news is a routine entry in the chronicle of Korea’s missile race. But it has a backstory worthy of an entire spy novel. Two years before those launches, on December 23, 2024, the Russian cargo ship Ursa Major sank some 60 miles off the Spanish coast. Its cargo manifest listed 129 empty containers, two Liebherr cranes, and “two large hatch covers.” According to a Spanish investigation cited by CNN, the captain, under pressure from investigators, admitted that the “hatch covers” were components of two submarine-grade nuclear reactors, and that the destination port, he believed, was North Korea’s Rason.
This is a story about how a 1950s-designed diesel boat, a blown-up ghost ship, and Kim Jong Un’s probable payment for soldiers sent to fight in the Kursk region all converge at one point.
Let’s start with the news. North Korea has tested “strategic” cruise missiles — in its nomenclature, a marker that they are intended to carry nuclear warheads — from underwater positions before: in March 2023 and January 2024, the older 8.24 Yongung submarine, displacing around 2,000 tons and equipped with one or two launch tubes, fired them. Specialists unanimously called it a testbed, not a combat vessel. Hero Kim Kun Ok was supposed to be the next step: at least 10 launch tubes, 86 meters long, around 3,000 tons displacement. On paper — a “tactical nuclear attack submarine.” In practice — a conversion of a Soviet Project 633 diesel submarine, known as the Romeo class, a design from the mid-1950s. The word “nuclear” in its designation refers to its intended armament, not its propulsion system: it is diesel-electric.
Analysts read the three years of silence after its launch as a catalogue of technical problems — possibly including the simple inability of the boat to submerge and level itself reliably. Seoul analyst Shin Jong-woo put it bluntly to AP: the October 14 launches mean the problems have been solved and weapons shakedown trials have begun ahead of operational service. Before deployment, in his assessment, one more test remains — ballistic missiles. Submarine expert Moon Geun-sik of Hanyang University put the point of the whole undertaking this way: missiles launched from beneath the water are “a formidable weapon because we don’t know when or where they will come from.” They do not have to hit — it is enough to force the adversary to search.
In retrospect, the public rhetoric fits the picture too: as Defense News notes, Kim Jong Un has prioritized a submarine-based nuclear deterrent since at least 2021, and Pyongyang has been steadily preparing the public for the idea that a second strike from beneath the waves is a matter of the next few years, not fantasy.
A brief lyrical digression, because the boat’s name is a separate genre of North Korean art. Hero Kim Kun Ok is named after a naval officer who, according to the official North Korean version, sank the American heavy cruiser USS Baltimore in the Battle of Jumunjin in July 1950. The problem is that Baltimore never took part in the Korean War: by that summer, the cruiser had been out of service for three years and laid up in reserve. According to non-North Korean archives, UN forces lost not a single man in that battle, while the North Koreans lost three torpedo boats.
A submarine tipped to become a carrier of nuclear deterrence bears the name of a man celebrated for sinking a ship that was not there. For the propaganda genre, that is almost honest: declare the victory first, reality will catch up later. The entire Hero Kim Kun Ok story is built on exactly that principle.
Now, the ship. Ursa Major, also known as Sparta-3, was a veteran of the Syrian campaigns, owned by the state-run Oboronlogistika company, which in October of that same year publicly reported that its ships were licensed to transport nuclear materials. On December 2, 2024, the vessel docked at the fuel port of Ust-Luga, then moved to the container terminal in St. Petersburg, and on December 11 put to sea with “Vladivostok” listed on its manifest. The manifest contained two “large hatch covers,” 129 empty containers, and two mobile Liebherr cranes.
Shipping empty containers and a pair of covers by sea around the entirety of Europe, from one Russian port to another, through a country with the world’s largest railway network — it is a logistical absurdity that the Spanish investigation by Cartagena maritime authorities examines separately. In its version, the cranes were meant to unload sensitive cargo upon arrival in Rason. A time-lapse video of the loading in Ust-Luga, analyzed by CNN, shows that the containers were placed in the hold so that empty space remained beneath the “hatch covers.” A Vantor satellite image from December 4 records two white objects on the quay, their shape matching the profile of nuclear reactor pressure vessels. The type, according to the Spanish investigation, was VM-4SG, like those used on Russian Delta IV strategic submarines. But the evidentiary basis is thin: the model’s dimensions have never been disclosed, and CNN explicitly notes that the objects in the image cannot be compared against a reference.
All the way, Ursa Major was escorted by two warships — Ivan Gren and Alexander Otrakovsky. Portugal’s air force and navy shadowed the vessel through their waters until they lost sight of it on the morning of December 22. About four hours later, already in Spanish waters, the ship sharply reduced speed; rescuers radioed to ask whether everything was all right. The crew replied that everything was fine. Another day later, the vessel abruptly changed course, and at 11:53 UTC on December 23 transmitted a distress signal: three explosions on the starboard side, apparently near the engine room. Two crew members died, 14 survived. A Spanish rescuer who inspected the vessel found the engine room sealed shut, and trash and fishing nets in two containers. According to a source familiar with the investigation, the ship remained afloat and showed no intention of sinking anytime soon.
But at around 9:50 that evening, Ivan Gren fired a series of red flares over the site — after which four more explosions thundered out. By then, one of the Russian warships had already ordered vessels in the area to keep a distance of two nautical miles. The order went out at 7:56 that evening, half an hour after the Spanish rescuer came alongside. Spain’s National Seismic Network told CNN that at precisely that moment and in that area it recorded four seismic signatures, resembling underwater mines or quarry blasts in character. By 11:10 that night, Ursa Major had sunk.
Four days later, Oboronlogistika called what happened “a targeted terrorist attack” and reported a 50-by-50-centimeter hole with metal bent inward and a deck strewn with fragments — wording equally suited to a mine or a torpedo. The Spanish investigation leans toward the latter: in its view, the breach may have been caused by a Barracuda-type supercavitating torpedo, which reaches enormous speeds thanks to an air bubble surrounding its body. One important detail: some models of these torpedoes carry no warhead at all — they punch through a hull by pure kinetic force. According to open-source assessments, the United States, several NATO allies, Russia, and Iran possess such torpedoes. A list that names no perpetrator.
On December 24, during questioning, Russian captain Igor Anisimov told investigators that the vessel had been carrying “components of two nuclear reactors similar to those used on submarines” — and admitted he was unsure whether nuclear fuel had been aboard. The Spanish government remained silent until February 23, when, under opposition pressure, it released a terse statement confirming precisely the captain’s words. The timing matters too: the disaster happened as the war in Ukraine was tilting in Moscow’s favor, while Washington had no desire whatsoever for direct escalation with Russia. CNN puts it cautiously: what happened “may represent a rare and hugely risky intervention by the Western military machine to disrupt the Russian transfer of an upgrade in nuclear technology to a key ally.” There is no direct evidence pointing to specific perpetrators. But the chronology speaks for itself: a ship with reactors in its hold explodes off the Spanish coast, its escort orders witnesses away, the wreckage is finished off, and then American aircraft spend two years looking down at the seabed.
Next comes a plot worthy of a Tom Clancy novel. A week after the ship’s loss, the Russian oceanographic vessel Yantar arrived over the wreck site — formally a research vessel; in NATO’s wording, in reality a ship accused of espionage and sabotage in European waters. Yantar lingered over the wreckage for five days, after which, according to a source in the Spanish investigation, another four explosions were recorded in the area — possibly destroying what remained of the hull on the seabed, together with everything still lying inside it. Data from tracking company Kpler confirm that the vessel left the area via Egypt and Algeria, and on January 15, 2025, transmitted a position signal 20 kilometers from Ursa Major’s last coordinates.
Then the Americans joined the case. According to open flight-tracker data, over the past year American WC-135 radiation reconnaissance aircraft — the very “sniffers” more often assigned to the skies above Russia’s Arctic and around Iran — flew over the coordinates of the sunken vessel twice: on August 27, 2025, and February 6, 2026. Whether they found traces of contamination is unknown; the Spanish government said it saw no radiation threat off its coast, and no evidence to the contrary has emerged. But the fact itself is telling: something lies underwater on the floor of the Mediterranean that gets checked with a Geiger counter twice in a year.
If we assume the reactors were being sent north, the question moves from forensics to geopolitics: what pays for them? Defense News calls it a “nuclear quid pro quo” in the Moscow-Pyongyang alliance — and the timeline suggests that payment is already underway. October 2024: Kim Jong Un sends his soldiers to fight against the Ukrainian offensive in the Kursk region. According to South Korean intelligence estimates cited by Defense News in February 2026, the Koreans suffered around 6,000 killed and wounded; on top of that came millions of artillery shells, ballistic missiles, vehicles, and equipment. “Before, he paid for North Korean weapons and soldiers with ballistic missile technology — but that commodity has been exhausted. Now you are seeing the potential leaching and distribution of submarine expertise to countries such as North Korea and Iran,” Peter Roberts, a maritime security expert at the University of Exeter, said during hearings in the British Parliament.
The chronology forms a straight line. September 2025: South Korea’s military reports intelligence indicating that Russia transferred two or three submarine propulsion modules to North Korea — a reactor, turbine, and cooling system — supposedly removed from Russian submarines being decommissioned. Two or three modules and the “two hatch covers” in Ursa Major’s manifest — a numerical match too neat to dismiss as analysts’ imagination. December 2025, the 25th: KCNA shows Kim Jong Un inspecting an “8,700-ton strategic nuclear-powered submarine” at the Sinpho shipyard; Seoul analysts note the fully assembled hull — a hint that the reactor has already been installed — while one retired South Korean submariner puts the timeline to sea trials at a matter of months. Analysts at the Center for Nonproliferation Studies, meanwhile, are monitoring new construction in Yongbyon that may turn out to be a test stand for naval reactors.
Still, the most level-headed voice in this story is John Ford of the James Martin Center for Nonproliferation Studies, in an interview with Defense News, and his skepticism deserves to be quoted word for word. To transfer nuclear warhead designs to North Korea: “impossible.” A propulsion plant: “more possible, but still very unlikely.” Russia has its own reasons to fear such leaks: anything that reaches Pyongyang can make its way through South Korean intelligence networks. Seoul is one recruitment away, and by passing reactor secrets to North Korea, Moscow effectively opens a window into its own secrets for its adversaries. And even with blueprints in hand, North Korea would still have to make the journey from theory to practice — a journey that took the United States and the USSR decades of the Cold War. “They simply don’t have the skills to operate underwater. And unless Russian submariners are going to sail with them on deployments — which I don’t believe — it will still take a very long time,” Ford says. Pyongyang’s main payment, he insists, is money; technology, if transferred at all, comes in the form of “answering questions and checking whether a component has been assembled correctly” — the way the United States once quietly helped the French nuclear program.
The October 14 launches are not a story about missiles. They are a story about a submarine beginning to prepare for service. Hero Kim Kun Ok spent three years without going to sea — and now fires from a launch tube and a torpedo tube simultaneously. The next expected step is ballistic missiles; after that, the boat will formally become a combat vessel. Diesel-powered, noisy, trackable from the moment it leaves port: a Romeo remains a Romeo under any propaganda paint job. But the simple fact that the platform has reached any kind of working condition shifts the conversation from “it will never work” to “when will it work.”
The story of Ursa Major is the best example I have encountered of what a transfer of prohibited technology looks like in the real world. No ceremonial documents or conferences — just empty containers, “hatch covers,” a military convoy, explosions, and wreckage over which Yantar hovered a week later. Formally, not a single element in this chain has been confirmed — and yet each rests on an independent body of evidence: the captain’s testimony, seismograms, tracker data, satellite imagery. That is what the texture of an interim status looks like — somewhere between “officially unconfirmed” and “obvious to any analyst.”
The timeline converges on a single point with frightening precision. October 2024: Kim Jong Un sends troops to the Kursk region. December 2024: a ship carrying “hatch covers” is blown up off Spain’s coast. January 2025: Yantar spends five days over the wreckage, followed by four more explosions. September 2025: Seoul reports two or three transferred submarine propulsion modules. December 2025: Kim inspects an 8,700-ton “nuclear” submarine in which, judging by the hull, the reactor is already installed. October 2026: Hero Kim Kun Ok’s first combat firing. Every link taken separately is an “unconfirmed report.” The chain assembled is no longer a set of reports. It is a trajectory.
But the sober scenario is worth keeping in mind too. Everything adds up even without Russian reactors: North Korea has been stubbornly building the submarine component of its nuclear deterrent on its own since at least 2021, its 8,700-ton project may rest on an indigenous reactor from Yongbyon, and the program’s “successes” may be inflated just as thoroughly as the legend of Kim Kun Ok and his cruiser. Skeptics like Ford cannot be dismissed: submarine nuclear secrets are, in Roberts’s words, “the crown jewels of military knowledge,” and Putin, by handing them out, is handing out his own vulnerabilities. Possibility is not fact. But the probability in this story has already crossed the threshold of “interesting” and entered the threshold of “alarming.”
Subjective opinion: what gets me most here is the detail about the “hatch covers.” A cargo manifest is a stupid, formal document filled out by some clerk, and that is precisely why “manhole covers” in the cargo column look more frightening than any encrypted dispatch: the system was so sure of its impunity that it did not bother inventing a plausible cover story. And one more thing: two years later, nobody has publicly named who blew up Ursa Major or why its crew died. The North Korean submarine bearing the name of a phantom victory is honest, at least, in that its legend is plainly fictitious. But the legend of a ship that “blew itself up” on the way to Vladivostok with two probable reactors in its hold still has no authors — and that may be the most honest detail in the entire story.