Encyclopedia Astronautica
RD-851


Yuzhnoye Nitric acid/UDMH rocket engine. 32.480 kN. R-16 (SS-7) stage 1 attitude control engine . Out of Production. Four thrusters are each gimbaled in one single axis. Isp=279s.

Application: R-16 (SS-7) stage 1 attitude control engine .

Chambers: 4. Engine: 403 kg (888 lb). Chamber Pressure: 66.20 bar. Propellant Formulation: AK27/UDMH. Thrust to Weight Ratio: 8.21. Oxidizer to Fuel Ratio: 2.45.

AKA: 8D63.
Status: Out of Production.
Unfuelled mass: 403 kg (888 lb).
Height: 1.70 m (5.50 ft).
Diameter: 3.54 m (11.61 ft).
Thrust: 32.48 kN (7,302 lbf).
Specific impulse: 279 s.
Specific impulse sea level: 243 s.
Burn time: 115 s.
First Launch: 1958-63.

More... - Chronology...


Associated Countries
See also
Associated Launch Vehicles
  • R-16 Ukrainian intercontinental ballistic missile. The Soviet Union's first practical ICBM, a two stage vehicle using storable propellants. Development began in 1956 and the missile was in service from 1962 to 1974. Peak deployment consisted of 186 launchers, about a third of them in missile silos, the rest in fixed 'soft' installations. More...

Associated Manufacturers and Agencies
  • Yuzhnoye Ukrainian manufacturer of rockets, spacecraft, and rocket engines. Yangel Design Bureau, Dnepropetrovsk, Ukraine. More...

Associated Propellants
  • Nitric acid/UDMH Drawing on the German World War II Wasserfall rocket, nitric acid (HNO3) became the early storable oxidiser of choice for missiles and upper stages of the 1950's. To overcome various problems with its use, it was necessary to combine the nitric acid with N2O4 and passivation compounds. These formulae were considered extremely secret at the time. By the late 1950's it was apparent that N2O4 by itself was a better oxidiser. Therefore nitric acid was almost entirely replaced by pure N2O4 in storable liquid fuel rocket engines developed after 1960. Unsymmetrical Dimethylhydrazine ((CH3)2NNH2) became the storable liquid fuel of choice by the mid-1950's. Development of UDMH in the Soviet Union began in 1949. It is used in virtually all storable liquid rocket engines except for some orbital manoeuvring engines in the United States, where MMH has been preferred due to a slightly higher density and performance. More...

Bibliography
  • Siddiqi, Asif A, Soviet Space Web Page, 1999 via Dietrich Haeseler. Web Address when accessed: here.
  • Shnyakin, V N, Shidkostnye Raketye Dvigateli - Opisanie i Osnovnye Tekhnicheskie Dannye, GKB Yuzhnoe "Yangel", Dnepropetrovsk 1996 via Dietrich Haeseler.

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