The RD-0255 is a propulsion module composed of an RD-0256 main engine and a RD-0257 vernier engine. Both are

liquid A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, ...

rocket engine A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accorda ...

, burning

UDMH Unsymmetrical dimethylhydrazine (UDMH; 1,1-dimethylhydrazine, НДМГ or codenamed Geptil) is a chemical compound with the formula H2NN(CH3)2 that is used as a rocket propellant. It is a colorless liquid, with a sharp, fishy, ammonia-like smell ...

in N₂O₄. The RD-0256 main engine operates in the oxidizer rich staged combustion cycle, while the vernier RD-0257 uses the simpler

gas generator A gas generator is a device for generating gas. A gas generator may create gas by a chemical reaction or from a solid or liquid source, when storing a pressurized gas is undesirable or impractical. The term often refers to a device that uses a ...

cycle. It was used on the R-36MUTTKh (

GRAU The Main Missile and Artillery Directorate of the Ministry of Defense of the Russian Federation (), commonly referred to by its transliterated Russian acronym GRAU (), is a department of the Russian Ministry of Defense. It is subordinate to the ...

:15A18) and R-36M2 (

:15A18M). Subsequently, it has been in the

Dnepr Dnepr may refer to: *Dnieper, a river flowing through Russia, Belarus and Ukraine to the Black Sea *Dnepr (motorcycle), a Ukraininan motocycle brand *Dnepr (rocket), a 1999 space launch vehicle *Dnepr radar, Soviet space surveillance and early warn ...

second stage and as of 2016 it is still in active service. The RD-0256 is an improved version of the RD-0228 (

: 15D84), itself composed of an RD-0229 (

: 15D84) main engine and a RD-0230 (

: 15D79) vernier engine. The RD-0228 was developed between 1967 and 1974 for the first generation of R-36M (

: 15D83)

ICBM An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons ...

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 START I (Strategic Arms Reduction Treaty) was a bilateral treaty between the United States and the Soviet Union on the reduction and the limitation of strategic offensive arms. The treaty was signed on 31 July 1991 and entered into force on 5 De ...

and

START II START II (Strategic Arms Reduction Treaty) was a bilateral treaty between the United States and Russia on the Reduction and Limitation of Strategic Offensive Arms. It was signed by US President George H. W. Bush and Russian President Boris Ye ...

the RD-0228 was retired and its successor, the RD-0256, only continued as the

References

External links

KbKhA official information on the engine. ''(Archived)''

Rocket engines of the Soviet Union Rocket engines using hypergolic propellant {{rocket-stub

See also

References

External links