JAXA identifies cause of Epsilon-S solid-fueled engine failure during test

Japan’s space agency JAXA has now identified the cause of the explosion that destroyed an Epsilon-S solid-fueled engine during a static fire test in July.

The explanation at the link is somewhat unclear, but the bottom line is that the failure was caused “by the melting and scattering of a metal part from the ignition device inside the engine.”

JAXA is working on a fix to prevent the part from melting, but the report provides no timeline on when the next Epsilon launch will occur. Nor do we know when Japan’s larger new rocket, the H3, will launch next as well, having failed during its first launch in the spring. At the moment, Japan is essentially out of the game.

Japan delays asteroid mission due to its rocket problems

Japan’s space agency JAXA has decided to delay its Destiny+ mission to the asteroid Phaethon until 2025 due to the continuing problems getting its Epsilon-S rocket off the ground.

Epsilon-S is intended as an upgrade to Japan’s Epsilon rocket, but its development has been plagued by failures. In October ’22 there was a launch failure of Epsilon, and in July ’23 the second-stage solid-fueled motor of Epsilon-S exploded during a test.

Phaethon is the parent asteroid of the Geminid meteor shower that occurs each year in December. According to the original plan Destiny+ would have done its fly-by of the asteroid in 2029. No new arrival date has been announced.

Solid-fueled second-stage motor for Japan’s new Epsilon-S rocket explodes during static fire test

A solid-fueled second stage of Japan’s upgraded Epsilon-S four-stage rocket exploded 57 seconds into a two minute static fire test today, likely preventing that rocket’s planned first launch this year.

Police received an emergency call shortly after 9 a.m. from a nearby resident reporting that she heard “a loud noise and saw smoke” rising from the Noshiro Rocket Testing Center.

JAXA said that an explosion occurred during a combustion test of the second-stage engine of the Epsilon S rocket, which is an improved model of the small solid-fuel Epsilon rocket, at the facility in the prefecture in the northeastern Tohoku region.

While explosions during static fire tests of liquid-fueled rockets occur periodically, for a solid-fueled motor to explode seems much rarer, and suggests the mix and placement of the solid-fuel within the stage did not occur properly.

This failure continues a string of failures within Japan’s government-run space program, including a failure during the first launch of its new large H3 liquid-fueled rocket earlier this year. At present Japan’s space agency JAXA has set August 26th for one of the last launches of the rocket the H3 is replacing, the H2A, carrying an X-ray space telescope and a small lunar lander. Though today’s failure involves very different technologies and should therefore not impact that launch, it is possible JAXA will stand down entirely to see if there was some systematic issue throughout its management. It sure appears there is.