H3 Rocket: Japan's Next-Generation Launch Vehicle
JAXA's H3 rocket is Japan's flagship launcher for the 2020s — designed for lower cost, higher cadence, and continued lunar and deep-space missions.
H3 is JAXA's and Mitsubishi Heavy Industries' next-generation rocket — the successor to the long-serving H-IIA. H3 is designed to roughly halve the per-flight cost of its predecessor while increasing payload capacity, supporting Japan's commercial, scientific, and exploration missions through the 2020s and 2030s.
H3 specifications
- Height
- 57 m (187 ft)
- Configurations
- H3-22S, H3-30S, H3-22L, H3-24L, H3-24W
- First-stage engines
- 2 or 3 LE-9 (LH2/LOX)
- Solid boosters
- 0, 2, or 4 SRB-3
- Upper-stage engine
- 1 LE-5B-3 (LH2/LOX)
- Payload to SSO
- Up to 4,000 kg
- Payload to GTO
- Up to 6,500 kg
Notable missions
- ALOS-3 (failed maiden flight, March 2023) — H3 lost
- ALOS-4 successful launch (July 2024)
- Kounotori-X HTV-X cargo flights to the ISS
- Future Martian Moons eXploration (MMX) mission to Phobos
Frequently asked questions
When did H3 first launch?
H3 first launched in March 2023, but the maiden flight ended in failure. H3 returned to flight in February 2024.
Is H3 reusable?
No. H3 is expendable, though JAXA is researching reusability for future generations.
What engines power H3?
Two or three LE-9 engines (Japan's most powerful liquid rocket engine ever) on the first stage, plus solid rocket boosters as needed.
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