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Mitsubishi Announces Ambitious Launch Schedule for Japan’s Unproven H3 Rocket

By Elizabeth Howell
Parabolic Arc
October 30, 2023
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Mitsubishi Announces Ambitious Launch Schedule for Japan’s Unproven H3 Rocket
Illustration of the H3 rocket, which has yet to successfully launch.
Image credit: JAXA.

Once Japan’s H3 rocket is finally ready, Mitsubishi Heavy Industries Ltd. plans to launch it into space at least six times a year, according to several media reports.

But the rocket, designed to carry heavier payloads than Japan’s H2 rocket, will have to overcome the fact that it’s yet to successfully launch. After a technical malfunction delayed its first launch from February to March, a failure to ignite in the second stage resulted in operators electing to send a destruct command to the rocket as a precaution. The mission failure also destroyed the H3’s payload, the Advanced Land Observing Satellite-3 (ALOS-3) Earth observation satellite.

The investigation is ongoing and no new launch date has been set for the system. However, Mitsubishi, which co-develops the rocket, told reporters this month it hopes to launch again for the other co-developer, the Japan Aerospace Exploration Agency (JAXA), as soon as early 2024. And once it does, it hopes to begin the ambitious new launch cadence.

“As with all new systems, they often take longer to bring to market and require extensive testing to assure reliability and performance goals,” Ted McFarland, who is president and managing director of the TM2 Space LLC consultancy, told SpaceRef. He is a commercial space practitioner with experience in Japan and east Asian space businesses.

Rocket lines often do fail on their first launch due to the inherent uncertainty in aerodynamics, fueling, and other conditions that are difficult for a simulation to predict. But McFarland emphasized the excellent track record upon which H3 is building.

H2 and H2A, he said, allowed Japan consistent and sovereign access to space for civil and commercial purposes for decades. Prominent missions included the Selene satellite to the Moon, the Venus orbiter Akatsuki, the Ikaros solar sailor, and the Hayabusa-2 sample return mission, along with numerous satellites for Japan and countries like Canada, the United Kingdom, and the United States.

“The H3 system has been in work as H2 follow-on for many years, with objectives of serving both Japanese and international customers with more launch mass capabilities at a lower price point than the H2 system,” McFarland added. “Just as H2 was a well-engineered launch vehicle, the H3 would appear to also be well-designed and engineered.”

H3 is a liquid propellant rocket with supplementary solid rocket boosters, designed to be able to launch missions to sun-synchronous orbit and geostationary transfer orbit. The latter will allow for missions to fly either to high Earth orbit or to other celestial destinations, if the plan calls for it.

Since H3 development began in 2013, of course, SpaceX has very much become the leading vendor for commercial, government, and security missions. But H3 remains a priority, as it will allow Japan independent access to space on its own territory without contracting an American company.

Some of the changes between H3 and H2 are intended to decrease the cost of launching, include using cheaper engines and a new combustion method on the first stage (called the expander bleed cycle) that aims to improve throttling conditions.

Japan is also attempting to position itself as a viable alternative to Russia, now that most of the space world does not deal in Russian launches anymore following Russia’s unsanctioned invasion of Ukraine in 2022. The International Space Station project continues for national space policy reasons, but other commercial and government missions are off the table; Russia has also withdrawn its Soyuz rocket from the international market for missions.

Should H3 launch relatively soon, it will emerge as another option for flying constellations of satellites. SpaceX will likely stick to its Falcon 9 and Falcon Heavy for Starlink missions, but other companies such as OneWeb and Amazon may pivot to different options, should those become available.

Elizabeth Howell

Business and science reporter, researcher and consultant.

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