YF-77
YF-77 is China’s liquid-hydrogen/liquid-oxygen booster engine used in pairs on the Long March 5 core first stage and the related Long March 5B configuration. CNSA identifies an approximately 50-tonne ground-thrust class per engine. These cryogenic core engines operate alongside the vehicle’s separate kerosene-fueled booster propulsion; their per-engine rating is distinct from the combined thrust of the complete launch vehicle.
Identity
- Aliases
- YF-77 hydrogen-oxygen engine
- Domains
- spaceflight
- Identity Level
- model
- Kind
- liquid-rocket-engine
- Name
- YF-77
- Status
- active
Details
- Description
- YF-77 is China’s liquid-hydrogen/liquid-oxygen booster engine used in pairs on the Long March 5 core first stage and the related Long March 5B configuration. CNSA identifies an approximately 50-tonne ground-thrust class per engine. These cryogenic core engines operate alongside the vehicle’s separate kerosene-fueled booster propulsion; their per-engine rating is distinct from the combined thrust of the complete launch vehicle.
- Propellants
- liquid hydrogenliquid oxygen
- Rocket Specs
- Sea Level Thrust
- …
Links
Assets & Meta
- Creation Time
- August 1, 2026 at 15:00:30 UTC
- Updated Time
- October 29, 2026 at 15:35:55 UTC
Other
- Sources
- Accessed Date
- 2026-08-14
- Note
- CNSA identifies two YF-77 hydrogen-oxygen engines on the Long March 5 core first stage and gives the approximately 50-ton ground-thrust class.
- Publisher
- China National Space Administration
- Title
- Long March 5: numbers behind the rocket
- Accessed Date
- 2026-08-14
- Note
- CNSA overview of propulsion developments for the Long March 5 launch-vehicle architecture.
- Publisher
- China National Space Administration
- Title
- New features of the Long March 5 carrier rocket
- Accessed Date
- 2026-08-14
- Note
- Government report independently identifies two YF-77 hydrogen-oxygen engines on the 5 m Long March core stage.
- Published Date
- 2024-02-24
- Publisher
- State Council Information Office of the People's Republic of China
- Title
- China launches new communication technology experiment satellite
- Accessed Date
- 2026-10-29
- Note
- Government launch report dated 24 February 2024 identifies two YF-77 hydrogen-oxygen engines on the 5-metre Long March 5 core stage.
- Publisher
- State Council of the People’s Republic of China
- Title
- China launches new communication technology experiment satellite