Encyclopedia Astronautica
Proton KM-4


Lox/LH2 propellant rocket stage. Loaded/empty mass 19,500/3,000 kg. Thrust 73.58 kN. Vacuum specific impulse 461 seconds. Planned version for Proton. Never developed.

Cost $ : 30.000 million.

Status: Development 1992..
Gross mass: 19,500 kg (42,900 lb).
Unfuelled mass: 3,000 kg (6,600 lb).
Height: 7.00 m (22.90 ft).
Diameter: 3.80 m (12.40 ft).
Span: 3.80 m (12.40 ft).
Thrust: 73.58 kN (16,541 lbf).
Specific impulse: 461 s.
Burn time: 780 s.

More... - Chronology...


Associated Countries
Associated Engines
  • RD-0225 Kosberg N2O4/UDMH rocket engine. 3.923 kN. Almaz space station orbital maneuvering. Hardware. Originally designed for UR-100 follow-ons spaceships. Two engines used on Almaz space station for orbital maneuvering, Pressure fed. Isp=287s. First flight 1974. More...
  • RD-56M Isayev lox/lh2 rocket engine. 73.580 kN. Proton and Angara upper stage KVRB, 12KRB upper stage for GSLV (India). In development. Isp=461s. First flight 2001. More...

Associated Propellants
  • Lox/LH2 Liquid oxygen was the earliest, cheapest, safest, and eventually the preferred oxidiser for large space launchers. Its main drawback is that it is moderately cryogenic, and therefore not suitable for military uses where storage of the fuelled missile and quick launch are required. Liquid hydrogen was identified by all the leading rocket visionaries as the theoretically ideal rocket fuel. It had big drawbacks, however - it was highly cryogenic, and it had a very low density, making for large tanks. The United States mastered hydrogen technology for the highly classified Lockheed CL-400 Suntan reconnaissance aircraft in the mid-1950's. The technology was transferred to the Centaur rocket stage program, and by the mid-1960's the United States was flying the Centaur and Saturn upper stages using the fuel. It was adopted for the core of the space shuttle, and Centaur stages still fly today. More...

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