New details have emerged about the failure of Japan’s H3 rocket last month, revealing the strange way its payload – a navigation satellite – was lost before reaching its target orbit.
The Japan Aerospace Exploration Agency (JAXA) launched the seventh mission of its H3 rocket on December 21, 2025, carrying the Michibiki 5 satellite. Shortly after takeoff, the the rocket’s second stage engine suffered an anomaly this caused its premature closure. JAXA officials recently revealed The root cause of the rocket’s anomaly: The cone-shaped protective covering that enveloped the satellite, known as the payload fairing, broke off about 4 minutes after launch. As a result, the satellite had to fight to survive before inevitably falling back to Earth.
JAXA has shared a lot of information about the recent anomaly, including this helpful illustration of the payload fairing detaching from the rocket.
Abnormal anomaly
The rocket business is undoubtedly tricky, and launches fail in all sorts of ways. This incident, however, might be one of the strangest ways a rocket has failed to deliver its payload.
The 207-foot-tall (63-meter) rocket got off to a rocky start, ending with a self-destruct order just 15 minutes after its first launch on March 6, 2023. Since its first launch failed, however, H3 has successfully completed five missions to date.
Shortly after the failure of the recent mission, JAXA declared This telemetry data showed that the pressure in the second stage hydrogen tank began to drop during the first stage engine burn. As a result, the first stage engine cutoff occurred 27 seconds later than planned, delaying the second ignition by 15 seconds. At the time, it was not yet known whether the satellite had separated from the rocket.
JAXA officials launched an investigation into the anomaly and discovered that the pressure began to drop when the rocket accidentally jettisoned its payload fairing. The satellite and payload adapter may have been damaged by the shock of fairing separation.
Images captured by a camera mounted on the adapter showed the satellite with apparent damage to its panels and insulation after the payload fairing broke away. A shower of debris surrounded the satellite, which clung to the rocket without its protective covering.
After the first stage stopped and separated, the shaking dislodged the satellite from its mooring, causing it to fall from the rocket. The camera showed the satellite lost in Earth orbit during its untimely descent towards Earth. JAXA officials said the satellite fell into the Pacific Ocean, in the same area as the H3’s first stage.
Lost in space
JAXA still does not know why the payload fairing suddenly detached, and this part of the anomaly is still under investigation.
Japan’s H3 rocket was 11 years in the making, a successor to the H-2A, which the agency retired in June 2025. Before its latest failure, JAXA aimed for at least two H3 launches per year. The rocket was scheduled to launch another QSZ satellite in 2026, as well as Japan’s HTV-X cargo spacecraft. The Japanese Martian Moons eXploration (MMX) mission is also expected to launch aboard the H3 rocket in late 2026.
The unusual separation of the payload fairings, however, could force the space agency to delay its plans.
