Encyclopedia Astronautica

Isayev Nitric acid/UDMH rocket engine. 4.089 kN. Zond 4-7 maneuvering engine. Out of Production. Spacecraft maneuvering engine, derivative of KTDU-35 without back-up engine. Isp=280s.

Application: Zond 4-7 maneuvering engine.

Chamber Pressure: 39.20 bar. Propellant Formulation: AK27I/UDMH. Oxidizer to Fuel Ratio: 1.85.

AKA: S5.53; KTDU-53.
Status: Out of Production.
Height: 1.14 m (3.73 ft).
Diameter: 2.50 m (8.20 ft).
Thrust: 4.09 kN (919 lbf).
Specific impulse: 280 s.
First Launch: 1962-67.

More... - Chronology...

Associated Countries
Associated Spacecraft
  • Soyuz 7K-L1 Russian manned lunar flyby spacecraft. 12 launches, 1967.03.10 (Cosmos 146) to 1970.10.20 (Zond 8). The Soyuz 7K-L1, a modification of the Soyuz 7K-OK, was designed for manned circumlunar missions. More...
  • Soyuz 7K-L1 PAO Russian manned spacecraft module. 12 launches, 1967.03.10 (Cosmos 146) to 1970.10.20 (Zond 8). Modification of Soyuz 7K-OK basic PAO service module with pump-fed main engines and separate RCS/main engine propellant feed system. Equipment-engine section. More...
  • Soyuz 7K-L1A Russian manned lunar orbiter. 2 launches, 1969.02.21 (N-1 3L) to 1969.07.03 (N-1 5L). Hybrid spacecraft used in N1 launch tests. More...
  • Soyuz 7K-L1E Russian manned lunar orbiter. 2 launches, 1969.11.28 (Soyuz 7K-L1E s/n 1) and 1970.12.02 (Cosmos 382). Modification of Soyuz circumlunar configuration used in propulsion tests of the Block D stage. 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.

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