Science

H3 Rocket Failure Disrupts Timeline for ‘Japanese GPS’

Yomiuri Shimbun file photo
The Michibiki No. 6 satellite is unveiled to the media in November 2024.

By Shiyori Iwase and Takako Sasamoto / Yomiuri Shimbun Staff Writers

21:00 JST, December 23, 2025

The failed launch on Monday of an H3 rocket, which was carrying the Michibiki No. 5 satellite, is a setback for Japan’s attempt to establish its own high-precision satellite positioning network.

The Michibiki satellite system, whose development has been led by the Cabinet Office, serves as Japan’s version of GPS, which is run by the United States.

The last satellite for the seven-unit array was set to be launched in February, with the government seeking full autonomy for positioning data. However, the launch failure means that timeline has been pushed back.

The Michibiki system consists of satellites that operate in two types of orbits: “quasi-zenith” orbits, which keep the satellites nearly directly above Japan for extended periods, and geostationary orbits over the equator, which make the satellites appear fixed in the sky to an observer on the ground.

With Michibiki, high-precision positioning data can be obtained with minimal errors, as signals are not obstructed by buildings and other ground-level structures.

Five Michibiki satellites are currently in service, including the No. 6 unit, which launched before the No. 5 unit. However, Japan needs seven satellites to achieve a fully independent, high-precision positioning system.

At present, the system must be supplemented with data from foreign satellites, including those used for GPS.

According to the Cabinet Office, Michibiki units 5, 6 and 7 can measure distances between satellites, allowing for even greater positioning accuracy.

These three satellites cost about ¥100 billion to develop in total. The seventh unit was scheduled to launch in February, with full operations set to begin in the next fiscal year.

The Self-Defense Forces also use these satellites for positioning data, which is vital to national security. The Cabinet Office is swiftly reviewing the cause of the launch failure and may revise the project’s master plan.