RD-191
| Country of origin | Russia | 
|---|---|
| Date | 2001 | 
| Designer | NPO Energomash | 
| Manufacturer | NPO Energomash / Proton-PM (in transition) | 
| Application | Main engine | 
| Predecessor | RD-170 | 
| Status | In use | 
| Liquid-fuel engine | |
| Propellant | LOX / RP-1 | 
| Mixture ratio | 2.6:1 | 
| Cycle | Oxidizer-rich staged combustion | 
| Configuration | |
| Nozzle ratio | 37:1 | 
| Performance | |
| Thrust, vacuum | 2,090 kN (470,000 lbf) at 100% throttle | 
| Thrust, sea-level | 1,920 kN (430,000 lbf) at 100% throttle | 
| Throttle range | 27–105% | 
| Thrust-to-weight ratio | 89:1 | 
| Chamber pressure | 25.8 MPa (3,740 psi) | 
| Specific impulse, vacuum | 337 s (3.30 km/s) | 
| Specific impulse, sea-level | 310.7 s (3.047 km/s) | 
| Burn time | 325 seconds (Angara A5 core stage) | 
| Gimbal range | 8° | 
| Dimensions | |
| Length | 4 m (13 ft) | 
| Diameter | 1.45 m (4 ft 9 in) | 
| Dry mass | 2,290 kg (5,050 lb) | 
| References | |
| References | |
The RD-191 (Russian: Ракетный Двигатель-191, romanized: Raketnyy Dvigatel-191, lit. 'Rocket Engine 191') is a high-performance single-combustion chamber rocket engine, developed in Russia and sold by Roscosmos. It is derived from the RD-180 dual-combustion chamber engine, which itself was derived in turn from the four-chamber RD-170 originally used in the Energia launcher.
The RD-191 is fueled by a kerosene / LOX mixture and uses an oxygen-rich staged combustion cycle. In the future the engine is expected to become a workhorse in the Russian space sector, as older launch vehicles are phased out of production and service.