Spaceflight Insider

Japan’s H-3 rocket to be more powerful, cost-effective than predecessor

Artist's rendering of the H-3 rocket.

Artist’s rendering of the H-3 rocket. Image Credit: JAXA

Japan is working on its newest launch vehicle, known as the H-3, which will be more powerful and cost-efficient than the H-2A booster currently in service. On July 20, the Japan Aerospace Exploration Agency (JAXA) announced it has completed the basic design of the rocket, scheduled to be ready for its maiden flight in 2020.

Concepts of the H-3 rocket in various configurations.

Concepts of the H-3 rocket in various configurations. Image Credit: JAXA

JAXA hopes the fact that H-3 will be equipped with simpler systems and that it will use commercially available components will allow it to be launched more frequently. It is hoped these factors will also reduce the cost of putting payloads into orbit. The agency expects the time needed for the assembly of the booster and payload encapsulation in the launch vehicle will be shortened.

“Reducing the number of hours to assemble the rocket and introducing automated inspection systems will allow an H-3 to be launched just a year after an order is placed,” said Masashi Okada, JAXA’s H-3 project team manager.

The Japanese space agency revealed it decided to shorten the launch preparation process after receiving voices from customers to swiftly launch their payloads and to increase the number of launch opportunities per year. H-3 will address these requests as its preparation period at the launch site, when compared to H-2A, will be reduced by half, allowing JAXA to lift-off six boosters of this type a year.

By using components available in other domestic industries and by creating a flow-line manufacturing system usually employed in general industrial productions, JAXA aims to halve the current cost per orbital launch to around $47 million.

H-3 is also planned to be capable of lifting heavier payloads than H-2A. The launcher’s capability will increase from 4.9 to 6.5 metric tons, mainly to meet the demands of geostationary satellites.

“Our aim is to have a launch vehicle that launches a payload ‘quicker’ and ‘easier’ with ‘high reliability’ while securing flexibility to answer the voices of customers,” JAXA stated on its website. “We have set a target for launch capability and price while focusing on the flexibility of launch services to cope with worldwide payload launch needs.”

Manufactured by Mitsubishi Heavy Industries, the two-stage H-3 rocket will be 207 feet (63 meters) tall and 17 feet (5.2 meters) in diameter. The first stage will be powered by two or three LE-9 engines and it could also be fitted with two or four solid rocket boosters, depending on payload’s mass. The second stage will have one engine, which is an improved LE-5B. Both stages will use liquid hydrogen as fuel and liquid oxygen as the oxidizer.

The development of H-3 was authorized by Japan’s government in May 2013. One year later, the System Requirements Review (SRR) was completed. Critical Design Review (CDR) of the rocket is scheduled for mid-2017.

The first H-3 launch in 2020 from the Tanegashima Space Center will see the rocket flying without boosters. The version with additional motors will be inaugurated in 2021.


Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.

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