YF-79
| Country of origin | China |
|---|---|
| Designer | Beijing Aerospace Propulsion Institute |
| Associated LV | Long March 9 |
| Predecessor | YF-75D |
| Status | In development |
| Liquid-fuel engine | |
| Propellant | Liquid oxygen / Liquid hydrogen |
| Mixture ratio | 6.0 |
| Cycle | Closed Expander Cycle |
| Configuration | |
| Chamber | 1 |
| Nozzle ratio | 160 |
| Performance | |
| Thrust, vacuum | 250 kilonewtons (56,000 lbf) |
| Chamber pressure | 7.0 MPa (1,020 psi) |
| Specific impulse, vacuum | 455.2 seconds (4.464 km/s) |
| Used in | |
| Long March 9 | |
| References | |
| References | |
The YF-79 is a liquid cryogenic rocket engine burning liquid hydrogen and liquid oxygen in a closed expander cycle. It is China's fourth generation of upper stage cryogenic propellant engine, after the YF-73, YF-75 and the YF-75D. It can do multiple restarts thanks to an electric spark igniter and a prototype was tested at 60% and 100% (25 tonnes-force (250 kN; 25 LTf; 28 STf)) thrust levels in December 2021.
It will be used on the third stage of the Long March 9.