RL-10 Rocket Engine Specifications.

The RL-10 was America's first liguid hydrogen fueled rocket engine. Six RL-10 engines were used in the S-IV second stage of the Saturn I rocket. Two RL-10 engines are used in the Centaur upper stages of Atlas and Titan rockets. There were proposals to use RL-10 powered Centaur upper stages on Saturn I, Saturn IB and Saturn V rockets.

Original RL-10 Specifications

Thrust (altitude): 15,000 lbf (66.7 kN)
Burn Time: 470 s
Design: Expander cycle
Specific Impulse: 433 s (433 lbf·s/lb, 4.25 kN·s/kg)
Engine Weight - dry: 298 lb (135 kg)
Height: 68 in (1.73 m)
Diameter: 39 in (0.99 m)
Ratio: 40 to 1
Propellants: LOX & LH2
Propellant Flow: 35 lb/s (16 kg/s)
Contractor: Pratt & Whitney
Vehicle Application: Saturn I / S-IV 2nd stage - 6-engines
Vehicle Application: Centaur upper stage - 2-engines

Current design

The RL-10 has been upgraded over the years and the most recent model, the RL-10B-2, powers the Delta 4 second stage. Some of the enhancements include an expanding nozzle and electro-mechanical gimbaling. Current specific impulse is 462 lbf·s/lb (4.53 kN·s/kg).

See also

• Spacecraft propulsion

External links

• RL-10B-2 at Astronautix