Second-stage engine issue halts seventh H3 mission
Japan’s H3 rocket suffered a setback on Sunday after failing to place the Michibiki 5 navigation satellite into its intended orbit. The rocket lifted off from Tanegashima Space Center at 8:51 p.m. EST, but the mission ended unsuccessfully when the second-stage engine did not restart as planned.
In a statement released early Monday, the Japan Aerospace Exploration Agency said the engine’s second ignition shut down prematurely, preventing the satellite from reaching geosynchronous orbit. As a result, the launch was declared a failure.
Setback for Japan’s Quasi-Zenith Satellite System
Michibiki 5, also known as QZS-5, weighed approximately 4,800 kilograms and was intended to expand Japan’s Quasi-Zenith Satellite System. The network is designed to complement GPS and provide more reliable positioning signals over Japan and parts of the Asia-Pacific region.
Japan currently operates four QZSS satellites, with long-term plans to expand the constellation to 11 spacecraft. Officials have said the system will play a growing role in regional navigation services once fully deployed.
H3 rocket development and recent track record
The two-stage H3 rocket was jointly developed by JAXA and Mitsubishi Heavy Industries as the successor to the H-2A launcher, which was retired earlier this year after 25 years of service.
While the H3 failed on its inaugural flight in March 2023, it later achieved five consecutive successful missions before Sunday’s anomaly. The latest failure marks the first setback for the vehicle since that recovery streak began.
Investigation launched after mission failure
JAXA has established a task force led by agency president Hiroshi Yamakawa to investigate the cause of the second-stage engine malfunction. Officials said the goal is to determine corrective measures before future launches.
“We would like to express our deepest apology to all those involved and to the public who had high expectations for this project,” JAXA said in its update.
