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The RD-856 (GRAU Index 8D69M), also known as the RD-69M, is a four-nozzle liquid-fuel rocket vernier engine, burning N2O4 and UDMH in a gas generator cycle.[3] It was used on the R-36, Tsyklon-2 and Tsyklon-3 second stage as thrust vector control by gimbaling of its nozzle.[3] The engine is distributed through a cylindrical structure that is integrated around the main engine RD-252 module. The structure includes aerodynamic protection for the nozzles.[2] The engine was started by a pyrotechnic ignitor.[2]
Country of origin | Soviet Union |
---|---|
First flight | December 16, 1965 |
Last flight | January 30, 2009 |
Designer | Yuzhnoye Design Bureau |
Manufacturer | Yuzhmash |
Application | Vernier |
Associated LV | R-36, Tsyklon-2 and Tsyklon-3 |
Status | Out of production |
Liquid-fuel engine | |
Propellant | N2O4 / UDMH |
Mixture ratio | 1.98 |
Cycle | Gas generator |
Configuration | |
Chamber | 4 |
Performance | |
Thrust, vacuum | 54.23 kN (12,190 lbf) |
Chamber pressure | 7.160 MPa (1,038.5 psi) |
Specific impulse, vacuum | 280.5 s (2.751 km/s) |
Burn time | Up to 163 s |
Restarts | 1 |
Gimbal range | ±30° |
Dimensions | |
Length | 0.9 m (2 ft 11 in) |
Diameter | 3.35 m (11.0 ft) |
Dry mass | 112.5 kg (248 lb) |
Used in | |
R-36, Tsyklon-2 and Tsyklon-3 second stage vernier | |
References | |
References | [1][2][3] |
The engine was serially produced between 1965 and 1992. It was first launched on December 16, 1965 on an R-36 and its last launch was on January 30, 2009 with the last launch of the Tsyklon-3. The production capability was restarted for the Tsyklon-4 but with the apparent cancellation of the program the engine would still be out of production.[4]