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RD-869

RD-864 (РД-864)
Country of origin Soviet Union
Date 1976-1978
First flight October 31, 1977
Designer Yuzhnoye Design Bureau
Manufacturer Yuzhmash
Application Upper Stage
Associated L/V R-36M UTTKh and Dnepr
Successor RD-869
Status In Service
Liquid-fuel engine
Propellant N2O4 / UDMH
Mixture ratio 1.8
Cycle Gas Generator
Configuration
Chamber 4
Performance
Thrust High Thrust Mode: 20.2 kN (4,500 lbf)
Low Thrust Mode: 8.45 kN (1,900 lbf)
Chamber pressure High Thrust Mode: 4.1 MPa (590 psi)
Low Thrust Mode: 1.7 MPa (250 psi)
Specific impulse High Thrust Mode: 309 seconds
Low Thrust Mode: 298 seconds
Burn time up to 600s
Restarts 25
Gimbal range +/- 55°
Dimensions
Length 4,020 mm (158 in)
Diameter 1,420 mm (56 in)
Dry weight 199 kg (439 lb)
Used in
R-36M UTTKh and Dnepr third stage
References
References
RD-869 (РД-869)
Country of origin Soviet Union
Date 1983-1985
First flight March 1986
Designer Yuzhnoye Design Bureau
Manufacturer Yuzhmash
Application Upper Stage
Associated L/V R-36M2
Predecessor RD-864
Status In Service
Liquid-fuel engine
Propellant N2O4 / UDMH
Mixture ratio 1.8
Cycle Gas Generator
Configuration
Chamber 4
Performance
Thrust High Thrust Mode: 20.47 kN (4,600 lbf)
Low Thrust Mode: 8.58 kN (1,930 lbf)
Chamber pressure High Thrust Mode: 4.1 MPa (590 psi)
Low Thrust Mode: 1.7 MPa (250 psi)
Specific impulse High Thrust Mode: 313 seconds
Low Thrust Mode: 302.3 seconds
Burn time up to 700s
Restarts 50
Gimbal range +/- 55°
Dimensions
Length 4,020 mm (158 in)
Diameter 1,420 mm (56 in)
Dry weight 196 kg (432 lb)
Used in
R-36M2 third stage
References
References

The RD-864 (GRAU: 15D177) is a Soviet liquid propellant rocket engine burning UDMH and nitrogen tetroxide in a gas generator combustion cycle. It has a four combustion chambers that provide thrust vector control by gimbaling each nozzle in a single axis +/- 55°. It is used on the third stage of the R-36M UTTKh (GRAU: 15A18) and Dnepr. For the R-36M2 (GRAU: 15A18M), an improved version, the RD-869 (GRAU: 15D300) was developed.

When the Soviet military developed an improved version of the R-36M ICBM, Yangel's OKB-586 developed a new engine for the third stage, the RD-864. Developed between 1976 and 1978 it flew for the first time on October 31, 1977. With the START I and START II the some 150 R-36M and R-36M UTTKh were retired and to be destroyed by 2007. So, a civilian application was looked for and during the 1990s, Yuzhnoe Design Bureau (the R-36M designer) successfully developed the Dnepr launch vehicle. It flew for the first time on April 21, 1999 and as of June 2016 it is still operational. So, while the production of the RD-864 has long since been finished, the engine is still to this day operational.


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