Encyclopedia Astronautica
Atlas MA-5AS


Lox/Kerosene propellant rocket stage. Loaded/empty mass 5,632/5,632 kg. Thrust 2,093.70 kN. Vacuum specific impulse 299 seconds.

No Engines: 2.

Status: Out of production.
Gross mass: 5,632 kg (12,416 lb).
Unfuelled mass: 5,632 kg (12,416 lb).
Diameter: 4.90 m (16.00 ft).
Span: 4.90 m (16.00 ft).
Thrust: 2,093.70 kN (470,682 lbf).
Specific impulse: 299 s.
Specific impulse sea level: 263 s.
Burn time: 172 s.
Number: 32 .

More... - Chronology...


Associated Countries
Associated Engines
  • RS-56-OBA Rocketdyne Lox/Kerosene rocket engine. 1046.8 kN. Out of production. Designed for booster applications. Gas generator, pump-fed. Isp=299s. Booster engine for Atlas II, IIA, IIAS. First flight 1991. More...

Associated Launch Vehicles
  • Atlas IIAS American orbital launch vehicle. The Atlas II booster was 2.7-meters longer than the Atlas I and included uprated Rocketdyne MA-5A engines. The Atlas I vernier engines were replaced with a hydrazine roll control system. The Centaur stage was stretched 0.9-meters compared to the Centaur I stage. Fixed foam insulation replaced Atlas I's jettisonable insulation panels. Higher performance RL10A-4 or RL10A-4-1 engines replaced Atlas II's RL10A-3-3A. The Atlas IIAS model added four Thiokol Castor IVA solid rocket boosters (SRBs) to the core Atlas stage to augment thrust for the first two minutes of flight. More...

Associated Propellants
  • Lox/Kerosene 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. In January 1953 Rocketdyne commenced the REAP program to develop a number of improvements to the engines being developed for the Navaho and Atlas missiles. Among these was development of a special grade of kerosene suitable for rocket engines. Prior to that any number of rocket propellants derived from petroleum had been used. Goddard had begun with gasoline, and there were experimental engines powered by kerosene, diesel oil, paint thinner, or jet fuel kerosene JP-4 or JP-5. The wide variance in physical properties among fuels of the same class led to the identification of narrow-range petroleum fractions, embodied in 1954 in the standard US kerosene rocket fuel RP-1, covered by Military Specification MIL-R-25576. In Russia, similar specifications were developed for kerosene under the specifications T-1 and RG-1. The Russians also developed a compound of unknown formulation in the 1980's known as 'Sintin', or synthetic kerosene. More...

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