Encyclopedia Astronautica
RD-251



rd251.jpg
RD-251
NPO Enerogmash Museum, November 1992
Credit: © Dietrich Haeseler
Glushko N2O4/UDMH rocket engine. 2643 kN. R-36-0 stage 1, Tsyklon 2 stage 1. In production. Assembly of 3 RD-250-type units. Isp=301s. First flight 1965.

Application: R-36-0 stage 1, Tsyklon 2 stage 1.

Chambers: 6. Thrust (sl): 2,366.000 kN (531,897 lbf). Thrust (sl): 241,300 kgf. Engine: 1,729 kg (3,811 lb). Chamber Pressure: 83.30 bar. Area Ratio: 14.7. Thrust to Weight Ratio: 156.15. Oxidizer to Fuel Ratio: 2.6.

AKA: 8D723.
Status: In production.
Unfuelled mass: 1,729 kg (3,811 lb).
Height: 1.76 m (5.78 ft).
Diameter: 2.52 m (8.26 ft).
Thrust: 2,643.00 kN (594,170 lbf).
Specific impulse: 301 s.
Specific impulse sea level: 269 s.
Burn time: 120 s.
First Launch: 1961-65.
Number: 131 .

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...
  • R-36-O Ukrainian orbital missile. The R-36-O was the only orbiting military nuclear weapon ever deployed, although in order to remain legal under international treaties it was a 'fractional orbital' weapon. Although American infrared early warning satellites invalidated the 'surprise attack' component of the concept, 18 missiles were operational from 1969 to 1983. More...
  • R-36 8K67P Ukrainian intercontinental ballistic missile. The R-36P was a version of the R-36 which could deploy three separate (but not independently-targeted) warheads instead of one. The concept was to ensure a wider zone of destruction and overpressure then a single warhead detonation would create. More...
  • Tsiklon-2 Ukrainian orbital launch vehicle. A government decree of 24 August 1965 ordered development by Yangel of a version of his R-36 rocket to orbit Chelomei's IS (Istrebitel Sputnik) ASAT and US (Upravlenniye Sputnik) naval intelligence satellites. The Tyklon 2 definitive operational version replaced the 11K67 launch vehicle from 1969 and was an adaptation of the 8K69 (SS-9) two stage ICBM. The IS and US Raketoplan-derived payloads had their own engines for insertion into final orbit. More...

Associated Manufacturers and Agencies
  • Glushko Russian manufacturer of rocket engines and rockets. Glushko Design Bureau, Russia. 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
  • Isakowitz, Steven J,, International Reference to Space Launch Systems Second Edition, AIAA, Washington DC, 1991 (succeeded by 2000 edition).
  • Haeseler, Dietrich, Information from NPO Energomash museum exhibit, Nov. 1992 via Dietrich Haeseler.
  • Russian Arms Catalogue, Vol 5 and 6, Military Parade, Moscow via Dietrich Haeseler.

Associated Stages
  • R-36-0-1 N2O4/UDMH propellant rocket stage. Loaded/empty mass 125,000/8,500 kg. Thrust 2,640.00 kN. Vacuum specific impulse 301 seconds. More...
  • R-36--1 N2O4/UDMH propellant rocket stage. Loaded/empty mass 122,300/6,400 kg. Thrust 2,651.70 kN. Vacuum specific impulse 301 seconds. Verniers 4 x RD-68M, 285 kN, maximum 42 degree gimbal angle. More...
  • Tsyklon 2-1 N2O4/UDMH propellant rocket stage. Loaded/empty mass 122,300/6,400 kg. Thrust 2,640.00 kN. Vacuum specific impulse 301 seconds. SL-11; 11K68;R-36M More...

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