SEOUL, South Korea — Japan’s brand-new H3 rocket was destroyed on its March 7 inaugural flight after the vehicle’s second-stage engine failed to ignite. This marked a major setback for the nation’s years-long efforts to develop a more capable and cost-effective alternative to the nation’s current workhorse, H-2A.
“A destruct command has been transmitted to H3 around 10:52 a.m. (Japan Standard Time), because there was no possibility of achieving the mission,” the Japanese space agency JAXA announced, confirming the engine failure. It did not share further details.
This ill-fated launch came after a series of delays, including one last month in which JAXA aborted the rocket’s first launch attempt moments before liftoff, citing an anomaly in side-mounted solid rocket boosters, which the agency later said stemmed from a problem with the electrical system that supplies power to the main engine.
Fixing the problem, the agency initially set the rocket’s second launch attempt for March 6, and it was delayed by one day due to unfavorable weather conditions.
The H3 lifted off from Tanegashima Space Center at 10:37 a.m. (JST) as scheduled, or 8:37 p.m. March 6 Eastern, carrying Advanced Land Observing Satellite-3 (ALOS-3), a 3-ton optical imaging satellite, built by Mitsubishi Electric Corporation.
Live footage showed the 63-meter expendable rocket soaring up into the sky with bright yellow flames spewed from two side-mounted solid rocket boosters. The side boosters were jettisoned about two minutes after liftoff and stage separation took place about five minutes after liftoff, according to telemetry. However, the second-stage engine’s ignition was not confirmed and the its velocity was seen declining as the rocket’s altitude reached about 620 kilometers. JAXA then announced that the rocket was ordered to self-destruct.
The troubled second stage was powered by a single LE-5B-3 hydrogen-fueled engine, developed by Mitsubishi Heavy Industries (MHI). It is an improved version of the LE-5B engine flown on the H-2A rocket. MHI remains silent on the accident.
Japan’s science minister Keiko Nagaoka said the outcome was “extremely regrettable” and apologized for “failing to meet the expectations of the public and related parties,” according to Kyodo News. The minister said a task force established at her ministry will work with JAXA to determine what caused the failure “as promptly and thoroughly as possible.”
H3 was co-developed by JAXA and Mitsubishi Heavy Industries at a cost of 200 billion yen (about $1.5 billion), as a successor to H-2A, which is due to retire after its 50th launch. H-2A has conducted 46 launches to date.
Japan’s journey to develop H3 was long and winding. JAXA began developing H3 in partnership with MHI in 2014. It is meant to replace H-2A that has been operational since August 2001 with a new one with “high flexibility, high reliability, and high cost-performance.” The rocket’s inaugural launch was originally scheduled for March 2021, but was pushed back by around two years due to issues with the newly developed LE-9 first-stage engine.
The problems were first uncovered during qualifications testing in May 2020, which included cracked turbine blades in the LE-9’s turbopump assembly and a hole seared into its combustion chamber wall. To fix these, JAXA and MHI had to redesign the engine’s fuel turbopump and apply those same changes to the engine’s oxygen turbopump.
There are four variants of the H3 rocket, each in a unique configuration of LE-9 engines and side-mounted solid rocket boosters. All four versions use a second stage is powered a single LE-5B-3 engine. Depending on the version of the rocket, it can place a payload of at least 4 tons into a sun synchronous orbit (SSO), with a maximum capacity of 6.5 tons into a geostationary transfer orbit (GTO). It is a significant improvement from H-2A’s capacity of 3.8 tons to SSO and 4 tons to GTO. Future upgrades could make it possible for the rocket to deliver cargo to the moon, including the planned lunar Gateway that NASA is pursuing in cooperation with JAXA, the European Space Agency and others.
