Encyclopedia Astronautica

Isayev Nitric acid/UDMH rocket engine. 18.920 kN. Luna 15-24 descent stage. Out of Production. Isp=314s. Comprised turbopump-fed high-thrust engine with plus KTDU-417-B low-thrust engine. Eleven ignitions for lunar orbit insertion and orbit corrections.

Two different oxidizers named.

Application: Luna 15-24 descent stage.


Chambers: 1 + 2. Throttled thrust(vac): 7.350 kN (1,652 lbf). Engine: 81 kg (178 lb). Chamber Pressure: 83.00 bar. Propellant Formulation: AK27I/UDMH. Thrust to Weight Ratio: 23.93. Oxidizer to Fuel Ratio: 1.8. Coefficient of Thrust vacuum: 0. Coefficient of Thrust sea level: 0.

AKA: KRD-417; KTDU-417; 11D417.
Status: Out of Production.
Unfuelled mass: 81 kg (178 lb).
Height: 0.79 m (2.59 ft).
Diameter: 0.73 m (2.39 ft).
Thrust: 18.92 kN (4,253 lbf).
Specific impulse: 314 s.
Burn time: 650 s.

More... - Chronology...

Associated Countries
Associated Spacecraft
  • Luna Ye-8 Russian lunar rover. 3 launches, 1969.02.19 (Ye-8 s/n 201) to 1973.01.08 (Luna 21). More...
  • Luna Ye-8-5 Russian lunar lander. 11 launches, 1969.06.14 (Ye-8-5 VA) to 1975.10.16 (Luna 24). Unmanned lunar soil sample return. More...
  • Luna Ye-8-LS Russian lunar orbiter. 2 launches, 1971.09.28 (Luna 19) to 1974.05.29 (Luna 22). Lunar surface mapping. Lunar Orbit (Selenocentric). Investigation of the moon and near-lunar space from the orbit of an artificial satellite. More...
  • Luna Ye-8-5M Russian lunar lander. 4 launches, 1974.10.28 (Luna 23) to 1976.08.09 (Luna 24 Return Vehicle). Lunar sample return. Conduct of further scientific investigation of the moon and circumlunar space. 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...

  • Kudryavtseva, V M, ed., Zhidkostnikh Raketnikh Dvigatley, Visshaya Shkola, Moscow, 1993.
  • Glushko, V P (ed), Kosmonavtika Entsiklopedi, Moscow 1985 via Dietrich Haeseler.
  • Kudryavtsev, V M, et.al., Osnovy Teorii i Rascheta, Moscow, Vysshaya Shkola, 1993 via Dietrich Haeseler.
  • Russian Arms Catalogue, Vol 5 and 6, Military Parade, Moscow via Dietrich Haeseler.
  • Siddiqi, Asif A, Soviet Space Web Page, 1999 via Dietrich Haeseler. Web Address when accessed: here.

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