J-2 (rocket engine): Meaning (information, definition, explanation, facts)

The J-2 was America's largest liguid hydrogen fueled rocket engine before the Space Shuttle main engines were created (SSME). Five J-2 engines were used in the S-II second stage of the Saturn V rocket. One J-2 engine was used in the Saturn V third stage (S-IVB) and the Saturn IB second stage (S-IVB). There were proposals to use various numbers of J-2 engines in the upper stages of the Nova rocket.

Original J-2 Specifications

Thrust (altitude): 200,000 lbf (890 kN)
Burn Time: 500 s
Specific Impulse: 418 s
Engine Weight - dry: 3,480 lb (1,578 kg)
Engine Weight - burnout: 3,609 lb (1,637 kg)
Ratio: 27.5 to 1
Propellants: LOX & LH2
Mixture Ratio: 5.00
Contractor: NAA/Rocketdyne
Vehicle Application: Saturn IB / S-IVB 2nd stage - 1-engine
Vehicle Application: Saturn V / S-II 2nd stage - 5-engines
Vehicle Application: Saturn V / S-IVB 3rd stage - 1-engine