Japan’s maiden launch of H3 rocket fails during second stage flight

by Adrian Beil

JAXA and Mitsubishi Heavy Industries launched – at the second attempt – to maiden launch of the H3 launch vehicle at 01:37 UTC Tuesday. However, the vehicle failed shortly after staging, via an apparent failure to light the second stage that was set to deploy the ALOS-3 optical satellite into a 669-kilometer Sun-synchronous orbit (SSO).

Controllers at the Tanegashima Space Center in Japan opted to activate the vehicle’s Flight Termination System (FTS) to destroy the stage after it was clear the mission would be unable to complete its mission.

During the first launch attempt on Feb. 17, an abort was called at T0 when the main engine shut down before the Solid Rocket Boosters were to ignite. The abort was found to have been caused by a voltage transient within the controller on the rocket’s first stage, and teams have corrected the issue ahead of Tuesday’s attempt. Details on the second stage failure during the second attempt were not immediately available.


Now lost, the ALOS-3 (Advanced Land Observing Satellite-3) was an optical imaging satellite that was to follow in the footsteps of the original Advanced Land Observation Satellite (ALOS). ALOS was launched in 2006 onboard an H-IIA.

Payload Fairing is moved to encapsulate the payload. (Credit: JAXA)

After initial issues were corrected with the satellite, where pictures would return too blurry to be useful for mapmaking purposes, the satellite operated until April 2011. At that time, contact with the satellite was lost after it was most likely hit by a meteorite. ALOS was declared dead in orbit in May 2011.

ALOS-2 is still operating after being launched in May 2014. It was equipped with a 1.2 GHz synthetic-aperture radar (SAR) sensor, which will help with cartography and disaster surveillance in Asia.

For ALOS-3, JAXA equipped the satellite with new and improved instruments to expand its performance. It features an improved sensor with a 0.8-meter resolution over a wide 70 km swath.

For surveillance, the satellite featured different modes that can fulfill various needs. The default operation mode is the strip map observation mode, which will scan an area with a width of 70 km along its track direction. It would have also been able to acquire pictures from two different directions using its stereoscopic observation mode and observe any given point in Japan within 24 hours using the pointing observation mode.

Along with its primary mission of disaster monitoring, the payload would have also helped accomplish secondary goals. These include updates on geospatial information in addition to research on coastal and land monitoring. 

The mass of the payload was approximately 3 tons with a size of 5.0 x 16.5 x 3.6 meters. It was designed to orbit the Earth at an altitude of 669 km with a design life of seven years.

H3 Rocket

The debuting rocket for this launch was the Japanese H3 rocket, built by Mitsubishi Heavy Industries in cooperation with JAXA. It was initially greenlit in May 2013 and, since then, has been in development as a more capable and cost-effective alternative to the H-IIA. It has planned launch costs of around $50-65 million. 

There are multiple variants of the H3 rocket. For this launch, it flew in the H3-22S configuration. The first of the two numbers represents the number of LE-9 engines on the main stage — in this case two. The second number indicates the number of solid rocket motors attached to the core stage. The letter after the numbers indicates the fairing used for the mission. S represents a short payload fairing, while L indicates a long payload fairing. A future W type will expand the width of the payload fairing to 5.4 meters.

The four variants of H3. (Credit: JAXA)

Depending on the version of the rocket, it can carry a payload of at least 4,000 kg into SSO, with a maximum capacity of 6,500 kg into a geostationary transfer orbit (GTO). Down the line, triple-core variants of the rockets are possible, similar to the United Launch Alliance Delta IV Heavy or the SpaceX Falcon Heavy. These would be used to support the Artemis program’s Gateway project, launching the HTV-X cargo resupply spacecraft.

All components of the H3 rocket. (Credit JAXA)

The first stage is powered by two LE-9 engines for this flight. The LE-9 is a new liquid hydrogen and liquid oxygen rocket engine that uses an expander bleed cycle. In this cycle, some of the hydrogen fuel functions as the coolant for the engine’s combustion chamber and nozzle before being used to spin the turbines that feed the fuel into the combustion chamber.

Like most other hydrogen engines, the LE-9 is highly efficient, sporting 426 seconds of specific impulse in a vacuum and a thrust of 1,471 kN. It measures 3.8 meters wide with a dry mass of 2.4 tons.

Most of the thrust during the beginning of the flight was provided by the two SRB-3 solid rocket boosters. These provide 2,158 kN of thrust each, with a specific impulse of 283.6 seconds. They burned for 105 seconds during the first stage flight before separating, leaving the main core stage to carry the rocket to space.

The upper stage – now a focus for investigating the failure – used an upgraded LE-5B engine called the LE-5B-3. This is an improved version of the H-IIA’s upper-stage engine. The LE-5B-3, like most of the H3’s components, was designed to lower costs and difficulty of assembly.

This engine also uses liquid hydrogen and liquid oxygen propellants and will operate at a specific impulse of 448 seconds with a maximum thrust of 137 kN. It is the last stage of the H3 rocket and is built for longer burns than its predecessor engine. 

Even without featuring reusability, JAXA and Mitsubishi want to make the H3 rocket price competitive with SpaceX’s Falcon 9 rocket.

Before this flight, the H3 launch vehicle completed a functional test in July 2020. In this test, various rocket functions were tested and powered on, system by system, to verify them before the flight. After completing these tests, the first flight rocket was shipped from the plant in January 2021. It completed a wet dress rehearsal in March 2021. After that, turbine vibration problems delayed the rocket’s maiden launch several times. 

In November 2022, the first flight rocket performed a successful static fire of its first-stage engines, clearing it for flight. The static fire lasted 25 seconds. 

The launch took place from the Yoshinobu Launch Complex at the Tanegashima Space Center in Japan. This complex was already used for rockets in the H-II family and will now also host the H3 rocket. Its first launch was performed in February 1994, with the H-II VEP/OREX mission.

Further information into the failure will be provided by JAXA in the coming days.

(Lead image: H3 returns to the pad for its second launch attempt. Credit: JAXA)

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