Agência Japonesa of The incident occurred shortly after the takeoff of Centro Espacial from Tanegashima, in
The space vehicle’s mission was to reinforce the Japanese satellite navigation system, essential for several critical applications in the country. The launch, which took place at 10:51 am (Japanese local time), was eagerly awaited after a series of postponements due to previous technical glitches.
Although the initial liftoff was successful, with the separation of the first stage and solid boosters occurring as planned, the anomaly in the second stage triggered an immediate alert at JAXA, which has already begun an in-depth analysis of the data to determine the extent of the problem and the fate of the satellite.
Challenges and delays prior to takeoff
The path to the launch of H3 8号機 on December 22 was marked by a series of technical obstacles that tested the JAXA team. The original date, scheduled for December 7, had to be canceled after the detection of an anomaly in an inertial sensor unit located in the second stage of the rocket, a vital component for attitude control during the flight.
The agency’s engineers acted quickly to replace the faulty components, which made a new launch attempt possible on December 17. Contudo, this second window was also interrupted seconds before ignition, when the system identified an insufficient flow in the launch pad’s cooling water injection equipment.
This cooling structure is crucial to protect both the rocket and the platform against the hot gases and intense vibrations generated at the moment of ignition. The failure was later attributed to an improper adjustment in a valve during maintenance procedures, forcing JAXA to resume standard verification and safety protocols. Esses incidents, however, did not cause damage to the rocket or satellite, which underwent additional integrity tests before being transported back to the platform on December 21.
Failure analysis in the second stage
JAXA’s announcement of the early second stage engine shutdown occurred approximately 30 minutes after liftoff. Este engine is responsible for the final acceleration of the vehicle and the precise insertion of the satellite into the planned orbit. In normal operating settings, the H3 rocket performs two ignitions at this stage to reach higher orbits.
Experts are intensively monitoring telemetry data to assess the exact speed and altitude the rocket managed to reach. The main concern is to determine whether the michibiki 5号機 achieved sufficient orbital speed to maintain its trajectory or whether, on the contrary, it was inserted into a lower orbit or remained on a ballistic trajectory, which would compromise its operational capacity.
The crucial role of mihibiki 5号機
The michibiki 5号機 satellite, manufactured by Mitsubishi Electric, integrates the quasi-zenithal positioning system (QZSS), often referred to as the Japanese GPS. The Este system is fundamental to the Japão technological infrastructure, offering a high-precision positioning service that complements and, in certain conditions, surpasses American GPS.
QZSS currently operates a constellation of five satellites, including replacement units, with the launch of 6号機 taking place in February 2025. The addition of michibiki 5号機 and the planned 7号機, scheduled for February 2026, aims to expand the system to a total of seven satellites by the end of fiscal year 2026.
Evolution and future of the H3 rocket
The H3 rocket was designed as the main launch vehicle for the Japão, succeeding the H2A and H2B models, with a strategic focus on reducing costs and increasing operational flexibility. The project, developed by JAXA and Mitsubishi Heavy Industries since 2014, involved a total investment of around 240 billion yen and introduced the new LE-9 engine in the first stage, designed to be more efficient and economical. The H3 has three main configurations that can be adapted to meet diverse payload demands, from Terra observation satellites to interplanetary missions. Após an initial failure in 2023 with the 1号機, which resulted in the second stage not igniting, stringent corrective measures were implemented, ensuring a series of five consecutive successes before this latest mission. The H3 program is seen as a pillar for the Japão to consolidate its position in the competitive commercial space launch market, competing with international reusable vehicles and expanding independent access to space.
Benefits of the QZSS system for Japão
The expansion of the QZSS system to seven satellites will allow the Japão to achieve complete autonomy in its national positioning system, reducing dependence on foreign technologies.
The system offers:
JAXA next steps and investigations
JAXA is currently in an intensive phase of collecting and analyzing data from telemetry and its tracking stations spread across the globe to assess the exact status of the mihibiki 5号機 satellite. The agency has committed to issuing updated statements as the investigation progresses and new information is confirmed.
If a failure in the satellite’s orbital insertion is confirmed, the implications could include the postponement of QZSS expansion plans for seven satellites, which are crucial for the system’s full operability. The next scheduled launch, H3 9号機, which will carry the mihibiki 7号機, is scheduled for February 1, 2026, and JAXA maintains its schedule of increasing the annual cadence of flights to meet the demands of its space program and the market.
