Encyclopedia Astronautica
RL-10A-4-2



rl10.jpg
RL-10
Credit: Lockheed Martin
Pratt and Whitney lox/lh2 rocket engine. 99.1 kN. In production. Isp=451s. Used on Atlas IIIB launch vehicle. First flight 2002. Two engines; electro-mechanical thrust vector control actuators replaced earlier hydraulically actuated system.

For Centaur IIIA, one of Centaur IIAS's two RL10A-4 engines is removed. The remaining engine is re-positioned to a center-mount, and electro-mechanical thrust vector control actuators replace the hydraulically actuated system previously in use. Guidance, tank pressurization, and propellant usage controls for both Atlas and Centaur phases are provided by the inertial navigation unit (INU) located on the forward equipment module. The first Centaur burn lasts about nine minutes after which the Centaur and its payload coast in a parking orbit. During the first burn, approximately ten seconds after ignition, the payload fairing is jettisoned. The second Centaur ignition occurs about 23 minutes into the flight, continues for about three minutes, and is followed several minutes later by the separation of the spacecraft from Centaur.

Engine: 167 kg (368 lb). Chamber Pressure: 39.00 bar. Area Ratio: 84. Thrust to Weight Ratio: 60.53.

Status: In production.
Unfuelled mass: 167 kg (368 lb).
Diameter: 1.53 m (5.00 ft).
Thrust: 99.10 kN (22,279 lbf).
Specific impulse: 451 s.
Burn time: 740 s.
Number: 16 .

More... - Chronology...


Associated Countries
Associated Spacecraft
  • Centaur V1 American space tug. One launch, , 2002. Upper stage / space tug - in production. Single engined Centaur for Atlas V, powered by one Pratt & Whitney RL10A-4-2 turbopump-fed engines burning liquid oxygen and liquid hydrogen. More...
  • Centaur IIIB American space tug. One launch, , 2002. Upper stage / space tug - out of production. Dual-engine Centaur for Atlas IIIB. More...

See also
Associated Launch Vehicles
  • Atlas IIIB American orbital launch vehicle. This was the first version of the Atlas to fly using Russian RD-180 engines; and the last version to fly using the original balloon-tank concept for the first stage. It differed from the Atlas IIIA in use of a stretched, two-engine upper stage, and had a brief three-year operational career in 2002-2005 before being superseded by the Atlas V. More...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
  • Centaur IIIB Lox/LH2 propellant rocket stage. Loaded/empty mass 22,960/2,130 kg. Thrust 198.32 kN. Vacuum specific impulse 451 seconds. Dual-engine Centaur for Atlas IIIB. The Lockheed Martin manufactured Centaur IIIB upper stage is powered by two Pratt & Whitney RL10A-4-2 turbopump-fed engines burning liquid oxygen and liquid hydrogen. The changes to Centaur for Atlas IIIB are a stretched tank (1.68 m) and the addition of the second engine. More...
  • Centaur V1 Lox/LH2 propellant rocket stage. Loaded/empty mass 22,825/2,026 kg. Thrust 99.19 kN. Vacuum specific impulse 451 seconds. Single-engine Centaur for Atlas V. Centaur is powered by either one or two Pratt & Whitney RL10A-4-2 turbopump-fed engines burning liquid oxygen and liquid hydrogen. For typical, high-energy mission applications, Centaur will be configured with one RL10 engine. Guidance, tank pressurization, and propellant usage controls for both Atlas and Centaur phases are provided by the inertial navigation unit (INU) located on the Centaur forward equipment module. More...
  • Centaur V2 Lox/LH2 propellant rocket stage. Loaded/empty mass 23,050/2,250 kg. Thrust 198.40 kN. Vacuum specific impulse 451 seconds. Dual-engine Centaur for Atlas V. For heavy payload, low earth orbit missions, Centaur will use two RL10 engines to maximize boost phase mission performance. More...

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