LE-5 family
The LE-5 family traces Japan’s liquid-hydrogen/liquid-oxygen upper-stage engines from H-I through H3. The original LE-5 used a gas generator, while LE-5A and LE-5B adopted expander-bleed cycles powered by hydrogen heated in regenerative cooling passages. Later LE-5B-2 and LE-5B-3 developments addressed vibration, efficiency and operating life. The family therefore includes different engine cycles and performance ratings, rather than one interchangeable upper-stage engine.
Identity
- Aliases
- LE-5 series
- Domains
- spaceflight
- Identity Level
- family
- Kind
- liquid-rocket-engine
- Name
- LE-5 family
- Status
- active
Details
- Description
- The LE-5 family traces Japan’s liquid-hydrogen/liquid-oxygen upper-stage engines from H-I through H3. The original LE-5 used a gas generator, while LE-5A and LE-5B adopted expander-bleed cycles powered by hydrogen heated in regenerative cooling passages. Later LE-5B-2 and LE-5B-3 developments addressed vibration, efficiency and operating life. The family therefore includes different engine cycles and performance ratings, rather than one interchangeable upper-stage engine.
- Propellants
- liquid hydrogenliquid oxygen
Links
Assets & Meta
- Creation Time
- July 29, 2026 at 08:48:33 UTC
- Updated Time
- October 29, 2026 at 15:30:45 UTC
Other
- Sources
- Accessed Date
- 2026-07-29
- Publisher
- Japan Aerospace Exploration Agency
- Title
- LE-5B
- Accessed Date
- 2026-07-29
- Publisher
- Japan Aerospace Exploration Agency
- Title
- LE-5B-3
- Accessed Date
- 2026-10-29
- Note
- JAXA compares the original gas-generator LE-5 with nozzle-expander LE-5A and chamber-expander LE-5B, and describes subsequent -2 and -3 improvements.
- Publisher
- Japan Aerospace Exploration Agency
- Title
- LE-5B and LE-5-series engine comparison