Encyclopedia Astronautica

Isayev Nitric acid/UDMH rocket engine. 4.090 kN. Out of Production. Isp=280s. Maneuvering engine for Salyut 1, derivative of KTDU-35. Longer burn time of 1000 s. Comprised single-chamber main engine plus dual-chamber back-up engine. Thrusts 4.09 + 4.03 kN

Application: Salyut 1.

Chambers: 1 + 2. Engine: 305 kg (672 lb). Chamber Pressure: 39.20 bar. Propellant Formulation: AK27I/UDMH. Thrust to Weight Ratio: 1.36. Oxidizer to Fuel Ratio: 1.85.

AKA: S5.66; KTDU-66.
Status: Out of Production.
Unfuelled mass: 305 kg (672 lb).
Height: 1.14 m (3.73 ft).
Diameter: 2.50 m (8.20 ft).
Thrust: 4.09 kN (919 lbf).
Specific impulse: 280 s.
Burn time: 1,000 s.
First Launch: 1970-71.

More... - Chronology...

Associated Countries
Associated Spacecraft
  • Salyut 1 Russian manned space station. 2 launches, 1971.04.19 (Salyut 1) and 1972.07.29 (Zarya s/n 122). Salyut 1 was the first DOS long duration orbital station. More...

See also
Associated Manufacturers and Agencies
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...

  • Glushko, V P (ed), Kosmonavtika Entsiklopedi, Moscow 1985 via Dietrich Haeseler.
  • Siddiqi, Asif A, Soviet Space Web Page, 1999 via Dietrich Haeseler. Web Address when accessed: here.

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