JAXA Pinpoints Fault That Scuppered H3 Rocket Launch

The Yomiuri Shimbun
The base of the H3 rocket is seen at Tanegashima Space Center in Minamitane, Kagoshima Prefecture, on Feb. 17.

The maiden launch of the H3 rocket was aborted last week because an abnormality in the electrical system that supplies power to the main engine was detected, according to the Japan Aerospace Exploration Agency.

JAXA reported its findings to an expert panel of the Education, Culture, Sports, Science and Technology Ministry on Wednesday.

The agency aims to launch the nation’s new flagship rocket during a window that runs until March 10.

The H3 rocket’s scheduled launch from the Tanegashima Space Center in Kagoshima Prefecture on the morning of Feb. 17 was aborted seconds before liftoff. A control unit detected an anomaly after the main engine ignited, so ignition signals were not sent to the booster rockets.

According to JAXA, the unit controls multiple functions, including power supply to the main engine. Just before the scheduled ignition of the boosters, an electronic circuit that supplies power from a battery for the main engine suddenly shut down.

The system in which the abnormality was detected supplies power to the engine when a switch inside the control unit is turned on by ground control.

It appears highly probable that some sort of problem occurred in the signal transmission between ground control and the switch in question, and the circuit shut down.

JAXA has confirmed there was no damage to the rocket’s fuselage or the government’s Daichi-3 Earth observation satellite that was on board.

“We’ll do everything we can to launch the rocket by March 10,” JAXA H3 rocket project manager Masashi Okada said.