Japan kind-of completes its sovereign satnav constellation

Japan has launched the final satellite in the current generation of its Quasi-Zenith Satellite System (QZSS), a sovereign satellite navigation network designed to supplement GPS. The satellite, "Michibiki No. 7" (QZS-7), reached orbit aboard a JAXA H3 rocket, giving Japan near-complete coverage from its own constellation for the first time. The system matters because standard GPS signals can struggle to reach parts of Japan's mountainous terrain and dense cities, so a locally controlled network improves both coverage and positional accuracy.

QZSS satellites use an inclined geostationary orbit shaped like a figure eight, ensuring at least one satellite sits high over Japan for much of the day, which is where the "quasi-zenith" name comes from. The programme began with an experimental satellite in 2010, followed by four production satellites launched between 2017 and 2021, before Japan expanded its ambitions to seven orbiters. QZS-6 launched successfully in February 2025, but a December 2025 H3 launch carrying QZS-5 failed due to a glue-related fault, meaning that satellite will not be replaced for now. Tuesday's successful QZS-7 launch leaves Japan just short of its full planned constellation, with three more satellites due in the 2030s.