New H3 Rocket Unveiled for Launch in FY 2024

Mitsubishi Heavy Industries (MHI) recently unveiled the fuselage of the latest H3 rocket, Japan's next-generation mainstay rocket. The company presented the rocket's airframe during a March 21 press tour at its Tobishima Plant (Tobishima Village, Aichi Prefecture). 

MHI is working towards an FY 2024 launch from the Tanegashima Space Center (TNSC) in Minamitane-cho, Kagoshima Prefecture. Unlike the first two spacecraft, the third H3 will not be a test unit, MHI announced. Therefore, MHI will likely equip the rocket with the advanced radar satellite DAICHI-4 as a disaster-preventative measure.

Mitsubishi's DAICHI-3 advanced optical satellite was lost in the Japan Aerospace Exploration Agency's (JAXA) failed H3 launch in March 2023. JAXA received much criticism for placing such a valuable satellite on a test rocket. In the February launch in 2024, the second H3 test model carried a dummy satellite instead of the DAICHI-4. JAXA considered the launch's success the end of the H3's test phase. 

Building On Success

Mayuki Niitsu, H3 project manager at MHI, addressed the assembled press before the new rocket's airframe. "Having succeeded in launching the second model, we cannot afford to fail this time," he declared. "We will continue working on the H3 piece by piece to ensure it is also a success." 

JAXA project manager Masashi Okada, who heads the entire H3 project, also spoke to the press. "Finally, we have reached the point where people worldwide can use the H3," he said. "Once we have successfully launched this third rocket, we would like to develop the H3 further," he revealed. Okada stated that both companies aim to "refine the H3 into a spacecraft that is even closer to our ideal rocket." 

MHI showed reporters the third rocket's first stage (about 37 meters or 121 feet). The company also presented a second stage (approximately 12 meters or 39 feet), which it will use in its fourth rocket and beyond. With a diameter of roughly 5.2 meters (17 feet), the first and second stages comprise the rocket's main body. Minus the fairing, main engine, and solid rocket boosters, the rocket will be approximately 57 meters (187 feet) long. 

On March 23, MHI transported the rocket's first stage to the TNSC. With the second stage, main engine, and boosters already delivered, assembly work will begin in preparation for launch.

More Launches Scheduled

The H3 is the successor to the current mainstay H2A rocket, which MHI will retire in fiscal 2024 after two more launches. MHI will also launch H3's fourth rocket before the end of March 2025. On board is expected to be the X-band Defense Communication Satellite, a dedicated communications satellite for the Ministry of Defense.

Other scheduled launches include the new HTV-X cargo vehicle and the Lunar Polar Exploration (LUPEX) spacecraft. JAXA also plans to launch the Martians Moons eXploration (MMX) satellite.

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(Read the article in Japanese.)

Author: Juichiro Ito