On December 22, 2025, Japan’s flagship H3 rocket suffered a major setback when its eighth flight (F8) failed to deliver a critical navigation satellite into orbit. This marks the second total failure for the H3 program since its debut in 2023, following a string of six successful launches that had briefly restored confidence in the vehicle.
The December 2025 Failure (Flight 8)
The rocket lifted off from the Tanegashima Space Center carrying the Michibiki-5 (QZS-5) satellite, a key component of Japan’s “homegrown GPS.” While the first-stage performance was nominal, the mission unraveled during the upper-stage operations:
* The Anomaly: During the first stage of flight, engineers noticed an abnormal drop in pressure in the second-stage liquid hydrogen tank.
* The Engine Failure: The second-stage engine (LE-5B-3) ran 27 seconds longer than planned during its first burn. When it attempted its second ignition to finalize the orbit, it shut down almost immediately.
* The Result: The satellite was left in an unusable low orbit (approximately 109 km by 441 km) and is expected to burn up in the atmosphere. JAXA has officially declared the launch a failure and established a special task force to investigate.
Impact on Japan’s “GPS” Goals
This loss is a significant blow to the Quasi-Zenith Satellite System (QZSS). Japan aims to operate a seven-satellite constellation to achieve full autonomy from the U.S. Global Positioning System (GPS). This failure delays that timeline, as Michibiki-5 was intended to be the sixth operational unit.
A History of “Ups and Downs”
The H3 rocket was designed by JAXA and Mitsubishi Heavy Industries to be a cheaper, more flexible successor to the reliable H-IIA. However, its journey has been volatile:
| Date | Mission | Outcome | Cause of Failure |
|---|---|---|---|
| March 7, 2023 | Test Flight 1 (TF1) | Failure | Second-stage engine failed to ignite due to an electrical circuit issue. |
| Feb – Oct 2024 | Flights 2, 3, 4 | Success | Successful deployment of several satellites and test payloads. |
| Feb – Oct 2025 | Flights 5, 7 | Success | Successful launch of Michibiki-6 and the HTV-X1 cargo craft. |
| Dec 22, 2025 | Flight 8 | Failure | Second-stage pressure drop and premature engine cutoff. |
|What’s Next?
JAXA President Hiroshi Yamakawa issued a formal apology, stating that the agency cannot proceed with future launches—including the scheduled Michibiki-7 launch in February 2026—until the cause of the December failure is fully understood.
This investigation is particularly high-stakes because the H3 is slated for international collaborations, including the LUPEX moon mission with India (Chandrayaan-5) and cargo resupply missions for the International Space Station (ISS).