RD-0255
| Country of origin | USSR |
|---|---|
| First flight | 1981-12-27 |
| Designer | OKB-154 |
| Associated LV | R-36M and Dnepr |
| Predecessor | RD-0229 |
| Status | In Service |
| Liquid-fuel engine | |
| Propellant | N2O4 / UDMH |
| Mixture ratio | 2.6 |
| Cycle | Oxidizer Rich Staged combustion |
| Configuration | |
| Chamber | 1 |
| Performance | |
| Thrust | 755 kilonewtons (170,000 lbf) |
| Used in | |
| RD-0255 Propulsion Module | |
| References | |
| References | |
| Country of origin | USSR |
|---|---|
| First flight | 1981-12-27 |
| Designer | OKB-154 |
| Associated LV | R-36M and Dnepr |
| Predecessor | RD-0230 |
| Status | In Service |
| Liquid-fuel engine | |
| Propellant | N2O4 / UDMH |
| Cycle | Gas Generator |
| Configuration | |
| Chamber | 4 |
| Used in | |
| RD-0255 Propulsion Module | |
| References | |
| References | |
The RD-0255 (Russian: Ракетный Двигатель-0255, romanized: Raketnyy Dvigatel-0255, lit. 'Rocket Engine 0255') is a propulsion module composed of an RD-0256 main engine and a RD-0257 Vernier thruster. Both are liquid-fuel rocket engines, burning a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide (N2O4) oxidizer. The RD-0256 main engine operates in the oxidizer rich staged combustion cycle, while the vernier RD-0257 uses the simpler gas generator cycle. It was used on the R-36MUTTKh (GRAU:15A18) and R-36M2 (GRAU:15A18M). Subsequently, it has been in the Dnepr second stage and as of 2016 it is still in active service.
The RD-0256 is an improved version of the RD-0228 (GRAU: 15D84), itself composed of an RD-0229 (GRAU: 15D84) main engine and a RD-0230 (GRAU: 15D79) vernier engine. The RD-0228 was developed between 1967 and 1974 for the first generation of R-36M (GRAU: 15D83) ICBM second stage, but was replaced on subsequent iterations by the RD-0256. The RD-0228 debut was on January 21, 1973. With the START I and START II the RD-0228 was retired and its successor, the RD-0256, only continued as the Dnepr.