Why Korea’s suicide drone, far pricier than a Shahed, crashed seconds after launch

What was meant to be a showcase of Korea's homegrown drone technology turned into an embarrassing flop on Tuesday when two loitering munitions plunged into the sea off the coast of Busan seconds after launch — a failure traced to a misaligned hatch door on the launcher in a preliminary probe.

The timing is awkward. The drone is due to complete system development next month, and it sits near the center of a military push to field cheap, expendable strike drones. Under a policy announced by Defense Minister Ahn Gyu-back in June, the military is to fast-track the system into service while acquiring more than 20,000 low-cost expendable drones and training 500,000 troops to fly them.

The Agency for Defense Development (ADD), the state-run institute leading the project, said Friday that the fault lay in the launcher rather than in the aircraft. The drone was fired from the upper tube of a two-tier stacked launcher on the flight deck of the Navy's amphibious ship Marado.

Directly beneath the drone, however, the lower left hatch door of the launcher sat out of alignment — in the path of the drone's exhaust — and was deformed by its launch. The deformed door threw the rocket booster's reaction force out of balance in the first instant of launch, deflecting the thrust and tipping the airframe into severe attitude instability, according to the ADD, which described the finding as a presumed cause.

The drones are expensive by the standards of their class. Each prototype costs about 800 million won ($580,000), and industry estimates put the figure at 100 million won to 200 million won even after mass production begins.

Iran's Shahed-136, which the Korean airframe closely resembles, is generally priced at $20,000 to $50,000 a unit. The U.S. Lucas, whose acronym the Korean program borrowed, was priced by the U.S. Central Command at about $35,000 when it was used in combat in February.

The agency described the finding as a presumed cause. It said the analysis drew on wireless status data transmitted by the drone, video from cameras installed near the launch tube, and comparison with earlier launches conducted under similar conditions.

Rocket-assisted launch, in which the drone is fired from inside a sealed canister with the help of a booster, is one of the core technologies the project is meant to prove, and was used in the maritime trial.

The ADD noted that in the opening seconds of a launch the aircraft is moving too slowly for its control surfaces to bite, so flight control has not yet engaged. The booster accelerates the drone and lifts it clear before the engine and propeller take over.

The ADD said a comparable launch conducted on April 24, run with the same parameters, showed the hatch doors were not deformed and every step, including takeoff, proceeded normally. Tuesday was the first time the problem had appeared, according to the agency.

In a stage-by-stage comparison released with the analysis, the ADD marked the April launch as normal through all three phases — launch, ascent and booster separation, and transition to propeller flight. Tuesday's attempt was logged as unable to fly, with attitude instability, loss of altitude and excessive deflection to the right.

"The operating status of the drone and the overall system was normal," the agency said, adding that as developers it was harder for them than for anyone that "a simple defect produced the worst possible outcome." It said the preparation for the trial had surfaced a number of issues it would need to address earlier in future, and that it would work to contribute to the military's force build-up.

The drone, a medium-class loitering munition under development since June 2024, was to have launched from the Marado in waters south of Busan, tracked a fast unmanned target boat and strike it. Both attempts ended within seconds with the drone uncermoniously crashing. System development is scheduled to be completed next month.

BY KIM MIN-YOUNG [[email protected]]