JAXA identifies cause of H3 rocket failure
In releasing today the preliminary results of its investigation into the failure on December 21, 2025 of the upper stage of its H3 rocket, Japan’s space agency pinned the likely cause on the rocket’s fairings.
Japan Aerospace Exploration Agency officials told a science ministry panel on Dec. 23 they suspect an abnormal separation of the rocket’s payload fairing—a protective nose cone shield—caused a critical drop in pressure in the second-stage engine’s hydrogen tank.
Engineers think the fairing might have hit the rocket at separation, damaging the tank.
Japan at present has no way to launch payloads. It has no operating independent commercial rocket companies, and its JAXA-owned H3 and Epsilon-S rockets have had repeated problems. The H3 failed on its first launch in 2023, causing a year-long delay, and Epsilon-S still in limbo because of repeated failures during development.
In releasing today the preliminary results of its investigation into the failure on December 21, 2025 of the upper stage of its H3 rocket, Japan’s space agency pinned the likely cause on the rocket’s fairings.
Japan Aerospace Exploration Agency officials told a science ministry panel on Dec. 23 they suspect an abnormal separation of the rocket’s payload fairing—a protective nose cone shield—caused a critical drop in pressure in the second-stage engine’s hydrogen tank.
Engineers think the fairing might have hit the rocket at separation, damaging the tank.
Japan at present has no way to launch payloads. It has no operating independent commercial rocket companies, and its JAXA-owned H3 and Epsilon-S rockets have had repeated problems. The H3 failed on its first launch in 2023, causing a year-long delay, and Epsilon-S still in limbo because of repeated failures during development.










