LE-9
JAXA LE-9 is the liquid-hydrogen/liquid-oxygen main engine for Japan's H3 first stage. It uses an expander-bleed cycle derived from LE-5-series experience; JAXA describes the cycle as reducing parts and abnormal-combustion risk and reports two- or three-engine H3 configurations. The current record preserves 1,472 kN per-engine first-stage thrust and 1,471 kN vacuum thrust from JAXA's H3 specifications.
Identity
- Domains
- spaceflight
- Identity Level
- model
- Kind
- liquid-rocket-engine
- Name
- LE-9
- Status
- active
Details
- Description
- JAXA LE-9 is the liquid-hydrogen/liquid-oxygen main engine for Japan's H3 first stage. It uses an expander-bleed cycle derived from LE-5-series experience; JAXA describes the cycle as reducing parts and abnormal-combustion risk and reports two- or three-engine H3 configurations. The current record preserves 1,472 kN per-engine first-stage thrust and 1,471 kN vacuum thrust from JAXA's H3 specifications.
- Lineage
- Note
- JAXA identifies LE-9 as a scaled-up application of the expander-bleed cycle used by the LE-5B series.
- Related Propulsion System
- Relationship
- technology-derived-from
- Sources
- Accessed Date
- 2026-07-29
- Publisher
- Japan Aerospace Exploration Agency
- Title
- LE-5B-3
- Propellants
- liquid hydrogenliquid oxygen
- Rocket Specs
- Cycle
- expander-bleed
- Sea Level Thrust Kn
- 1,472
- Vacuum Specific Impulse S
- 422
- Vacuum Thrust Kn
- 1,471
Links
- Official Url
- https://www.rocket.jaxa.jp/rocket/h3/
Assets & Meta
- Creation Time
- July 29, 2026 at 08:49:33 UTC
- Updated Time
- August 22, 2026 at 07:20:17 UTC
Other
- Sources
- Accessed Date
- 2026-07-29
- Note
- Supports the legacy vehicle installation and the narrow canonical identity used during migration.
- Publisher
- Official vehicle or program source
- Title
- H3-30S official vehicle reference
- Accessed Date
- 2026-07-29
- Publisher
- Japan Aerospace Exploration Agency
- Title
- H3 Launch Vehicle: LE-5B-3 and LE-9
- Accessed Date
- 2026-07-29
- Publisher
- Japan Aerospace Exploration Agency
- Title
- LE-5B-3
- Accessed Date
- 2026-08-22
- Note
- JAXA identifies LE-9 as the H3 main engine, documents its expander-bleed cycle and LE-5-series heritage, and describes the two- or three-engine first-stage configurations.
- Publisher
- Japan Aerospace Exploration Agency
- Title
- H3 Launch Vehicle
- Accessed Date
- 2026-08-22
- Note
- JAXA's H3 brochure lists two- or three-unit LE-9 first-stage configurations and 1,472 kN thrust per engine.
- Publisher
- Japan Aerospace Exploration Agency
- Title
- H3 Launch Vehicle