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JAXA / Mitsubishi Heavy Industries · Operational · jp · Launch Vehicle

H3

Japan's modular next-generation medium-lift rocket; 3 launches in 2025 after 2024 debut.

Verified 2026-06-17 · First flight 2024-02-17

Operator page

Systems cutaway

Systems
H3 — systems cutaway schematicPropulsion
2× LE-9 LOX/LH2 main engines on first stage; 0 or 2 or 4× SRB-3 solid strap-ons; LE-5B-3 LOX/LH2 upper stage; 4,413 kN (2-booster baseline) liftoff thrust.
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Structures
5.2 m diameter; 63 m height; modular configuration for different payload classes.
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H363 m
Propulsion

2× LE-9 LOX/LH2 main engines on first stage; 0 or 2 or 4× SRB-3 solid strap-ons; LE-5B-3 LOX/LH2 upper stage; 4,413 kN (2-booster baseline) liftoff thrust.

Structures

5.2 m diameter; 63 m height; modular configuration for different payload classes.

Specs & Metrics

Payload to LEO ↑ better
16,000 kg
H3-24L variant; H3-30 can carry ~4,000 kg
Maximum payload mass deliverable to low Earth orbit (~200–400 km circular), in the vehicle's stated reference configuration.
Payload to GTO ↑ better
6,500 kg
H3-24L variant
Maximum payload mass deliverable to geostationary transfer orbit (~185 × 35,786 km), in the stated reference config.
Liftoff Thrust ↑ better
4413 kN
baseline 2-booster config; up to 12,142 kN with 4 boosters
Total first-stage thrust at liftoff (sea-level), in kilonewtons, summing all active engines and solid strap-ons.
Liftoff Mass ↓ better
574 t
H3-24L
Total vehicle mass at liftoff including propellant, payload, and all stages, in metric tonnes.
Vehicle Height ↓ better
63 m
Full stack height at liftoff, in metres, including fairing or spacecraft.
Mission Success Rate ↑ better
83.3%
5 successes, 1 failure (debut F2 failure Feb 2023 aborted; maiden success F3 Feb 2024)
Percentage of launch attempts rated as full mission successes over the vehicle's complete flight history.
Launches in 2025 ↑ better
3
Flights 5, 6, 7 in Feb, Jun, Oct 2025
Total number of launch attempts conducted in calendar year 2025 (Jan 1 – Dec 31 UTC).

Subsystems

propulsion

2× LE-9 LOX/LH2 main engines on first stage; 0 or 2 or 4× SRB-3 solid strap-ons; LE-5B-3 LOX/LH2 upper stage; 4,413 kN (2-booster baseline) liftoff thrust.

structures

5.2 m diameter; 63 m height; modular configuration for different payload classes.