Encyclopedia Astronautica
Pegasus Tanks


xLox/LH2 propellant rocket drop tank. Loaded/empty mass 20,000/3,700 kg. Vacuum specific impulse 459 seconds.Four tanks jettisoned at 130 seconds after liftoff; two at 250 seconds, last two at orbital insertion, 360 seconds after liftoff.

Cost $ : 6.000 million. No Engines: 0.

Status: Study 1966.
Gross mass: 20,000 kg (44,000 lb).
Unfuelled mass: 3,700 kg (8,100 lb).
Height: 18.90 m (62.00 ft).
Diameter: 4.57 m (14.99 ft).
Span: 4.57 m (14.99 ft).
Specific impulse: 459 s.
Specific impulse sea level: 359 s.
Burn time: 130 s.

More... - Chronology...


Associated Countries
Associated Engines
  • None Indicates that the stage shown is a propellant tank. The engine on another stage is drawing propellants from this tank. Performance shown is for that of the engine on the other stage. First flight 1964. More...

Associated Launch Vehicles
  • Pegasus VTOVL American SSTO VTOVL orbital launch vehicle. Bono design for semi-single-stage-to-orbit ballistic VTOVL launch vehicle. Drop tanks were shed on the way to orbit. Pegasus could deliver either a Satun V-size payload to LEO or 172 passengers and their luggage the 12,000 km from Vandenberg to Singapore in 39 minutes. 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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