Epsilon S Rocket Explosion Occurs during Engine Combustion Test; Marks Second Incident since Combustion Test Accident in July 2023 (UPDATE 1)

The Yomiuri Shimbun

11:22 JST, November 26, 2024 (updated at 15:00 JST)

An explosion occurred Tuesday morning during a ground combustion test involving the second-stage engine of Japan’s new Epsilon S solid-fuel rocket. The incident was caused by abnormalities during the test at the Japan Aerospace Exploration Agency’s Tanegashima Space Center in Kagoshima Prefecture, said JAXA.

No injuries from the explosion were reported, and JAXA is investigating the details. An accident involving Epsilon S’s combustion test also occurred in July 2023.

According to JAXA and other sources, Tuesday’s combustion test was scheduled to last for about two minutes from around 8:30 a.m. at the center’s test site to verify the the second-stage engine’s performance. However, the engine exploded and caught fire immediately after the test began.

The 27-meter-long Epsilon S is an improved version of the Epsilon domestic flagship rocket, and was jointly developed by JAXA and IHI Aerospace Co. They were improving the launch capacity by making the second-stage engine and other components larger.

The second-stage engine exploded in July 2023 during a combustion experiment at the Noshiro Rocket Testing Center in Akita Prefecture.

JAXA investigated the cause and concluded that heat had melted part of the ignition device. The agency then covered the ignition device with heat-insulating material for the latest test.

Epsilon S was scheduled to be launched in 2024, but Tuesday’s accident has made it impossible to proceed as planned.