Encyclopedia Astronautica

Isayev Nitric acid/Amine rocket engine. 45.5 kN. Used on Luna E-6 probes. Out of Production. Isp=287s. First turbopump engine with surface tension propellant management devices in tanks, allowing re-ignition in zero-G.

Three fixed steering thrusters using the turbine exhaust gas for attitude control. Thrusts 45.5 + 0.245 kN. System mass 138.2 kg incl. tanks.

Application: Luna E-6, Luna E-6LF, Luna E-6LS, Luna E-6M, Luna E-6S.


Chambers: 1 + 3. Engine: 48 kg (105 lb). Chamber Pressure: 62.80 bar. Area Ratio: 43.4. Propellant Formulation: AK271/TG-02. Thrust to Weight Ratio: 50.4658385093168. Oxidizer to Fuel Ratio: 3.6. Coefficient of Thrust sea level: 0.

AKA: S5.5; S5.5A; KTDU-5A.
Status: Out of Production.
Unfuelled mass: 48 kg (105 lb).
Height: 1.91 m (6.26 ft).
Diameter: 1.70 m (5.50 ft).
Thrust: 45.50 kN (10,229 lbf).
Specific impulse: 287 s.
Specific impulse sea level: 117 s.
Burn time: 43 s.

More... - Chronology...

Associated Countries
Associated Spacecraft
  • Luna E-6 Russian lunar lander. 12 launches, 1963.01.04 (Sputnik 25) to 1966.01.31 (Luna 9). E-6 probes were designed by Korolev's OKB-1 with the objective of making the first soft landing on the moon and beaming back pictures of the surface. More...
  • Luna E-6S Russian lunar orbiter. 2 launches, 1966.03.01 (Cosmos 111) to 1966.03.31 (Luna 10). More...
  • Luna E-6LF Russian lunar orbiter. 2 launches, 1966.08.24 (Luna 11) to 1966.10.22 (Luna 12). Photographed lunar surface and orbital space environment in preparation for manned missions. More...
  • Luna E-6M Russian lunar lander. One launch, 1966.12.21, Luna 13. Modernized version of the E-6 with the ALS lander mass increased from 84 kg to 150 kg. Conducted further scientific investigation of the moon and circumlunar space. More...
  • Luna E-6LS Russian lunar orbiter. 3 launches, 1967.05.17 (Cosmos 159) to 1968.04.07 (Luna 14). The E-6LS was a radio-equipped version of the E-6 used to test tracking and communications networks for the Soviet manned lunar program. More...

See also
Associated Manufacturers and Agencies
Associated Propellants
  • Nitric acid/Amine 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. Early storable rocket systems sought to improve ignition characteristics and perforamance by eliminating the kerosene portion of the fuel. An amine is an organic compound produced when one or more hydrogen atoms of ammonia is replaced with organic groups. Mixed amine fuels were first developed by the Germans in World War II. TONKA-250, developed for the Wasserfall rocket, was used by the Russians after the war in various engines under the specification TG-02. More...

  • Harvey, Brian, "Some Details on Project Zenith (1957 Onwards)", Spaceflight, 1993, Volume 35, page 382.
  • Kudryavtseva, V M, ed., Zhidkostnikh Raketnikh Dvigatley, Visshaya Shkola, Moscow, 1993.
  • Glushko, V P, Albom Konstruktsiy ZhRD, Vol. 1 1968, Vol. 3 & 4 1969 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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