Encyclopedia Astronautica
J-2-SL


Rocketdyne lox/lh2 rocket engine. 996.7 kN. Study 1966. Sea level version of J-2 with reduced expansion ratio proposed for Saturn II first stage use. Isp=390s.

Thrust (sl): 729.300 kN (163,953 lbf). Thrust (sl): 74,366 kgf. Engine: 1,360 kg (2,990 lb). Chamber Pressure: 30.00 bar. Area Ratio: 14. Thrust to Weight Ratio: 74.73.

Status: Study 1966.
Unfuelled mass: 1,360 kg (2,990 lb).
Thrust: 996.70 kN (224,067 lbf).
Specific impulse: 390 s.
Specific impulse sea level: 275 s.
Burn time: 310 s.

More... - Chronology...


Associated Countries
See also
Associated Launch Vehicles
  • Saturn INT-19 North American study, 1966. Saturn variant with 4 to 12 Minuteman motors as boosters, Saturn II stage as core, and Saturn IVB upper stage. Saturn II stage would be fitted with lower expansion ratio engines and would ignite at sea level. Various combinations of numbers of strap-ons, propellant loading of the two core stages were studied. More...

Associated Manufacturers and Agencies
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...

Associated Stages
  • Saturn II-SL Lox/LH2 propellant rocket stage. Loaded/empty mass 490,952/44,240 kg. Thrust 5,500.77 kN. Vacuum specific impulse 390 seconds. Saturn II modifed with reduced expansion ratio J-2 engines for use a first stage (sea level launch). Requires solid rocket motor augmentation to get off the ground. More...

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