Encyclopedia Astronautica
RD-855



wrd855.jpg
RD-855
Credit: Yuzhnoye
Yuzhnoye N2O4/UDMH rocket engine. 328 kN. Tsyklon stage 1 attitude control engine. Out of Production. Isp=292s. Four-chamber pump-fed single-run engine burned hypergolic propellants in a gas generator scheme.

The autonomous four-chamber pump-fed single-run engine burned hypergolic propellants in a gas generator scheme (without afterburning of the generator gas). Most valves were activated by pyrotechnics. The engine flow scheme tapped off both propellants to the feed the oxidizer tank pressurization gas generator, as well generator gas for the fuel tank pressurization mixer. Thrust controlled to within 10% of nominal value, propellant mixture ratio within 5.6%. Engine thrust controlled by gimballing each of the four chambers in one plane, 41 deg.

Application: Tsyklon stage 1 attitude control engine.

Characteristics

Chambers: 4. Thrust (sl): 285.400 kN (64,160 lbf). Thrust (sl): 29,103 kgf. Engine: 320 kg (700 lb). Chamber Pressure: 65.70 bar. Thrust to Weight Ratio: 90.94. Oxidizer to Fuel Ratio: 1.97.

AKA: D-68M; RD-855.
Status: Out of Production.
Unfuelled mass: 320 kg (700 lb).
Height: 1.74 m (5.71 ft).
Diameter: 3.81 m (12.49 ft).
Thrust: 328.00 kN (73,737 lbf).
Specific impulse: 292 s.
Specific impulse sea level: 254 s.
Burn time: 127 s.
First Launch: 1962-67.

More... - Chronology...


Associated Countries
See also
Associated Launch Vehicles
  • Tsiklon Ukrainian intercontinental ballistic missile. The R-36 ICBM was the largest ever built and the bogeyman of the Pentagon throughout the Cold War. Dubbed the 'city buster', the 308 silos built were constantly held up by the US Air Force as an awesome threat that justified a new round of American missile or anti-missile systems. On the other hand, the Americans were never motivated to build and deploy corresponding numbers of their equivalent, the liquid propellant Titan 2. Derivatives of the R-36 included the R-36-O orbital bombing system, the Tsiklon-2 and -3 medium orbital launch vehicles, and the replacement R-36M missiles. With the collapse of the Soviet Union, the design and manufacturing facility ended up in independent Ukraine. Accordingly the missile was finally retired in the 1990's, conveniently in accordance with arms reduction agreements with the Americans. More...

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

Associated Propellants
  • N2O4/UDMH Nitrogen tetroxide became the storable liquid propellant of choice from the late 1950's. 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
  • Shnyakin, V N, Shidkostnye Raketye Dvigateli - Opisanie i Osnovnye Tekhnicheskie Dannye, GKB Yuzhnoe "Yangel", Dnepropetrovsk 1996 via Dietrich Haeseler.

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