Encyclopedia Astronautica
Ariane 5 EPC


Lox/LH2 propellant rocket stage. Loaded/empty mass 186,000/12,700 kg. Thrust 1,114.00 kN. Vacuum specific impulse 434 seconds. 15.2 tonnes increased propellant by moving liquid oxygen bulkhead.

AKA: H173.
Status: In development.
Gross mass: 186,000 kg (410,000 lb).
Unfuelled mass: 12,700 kg (27,900 lb).
Height: 30.50 m (100.00 ft).
Diameter: 5.46 m (17.91 ft).
Span: 5.46 m (17.91 ft).
Thrust: 1,114.00 kN (250,437 lbf).
Specific impulse: 434 s.
Specific impulse sea level: 335 s.
Burn time: 650 s.
Number: 26 .

More... - Chronology...


Associated Countries
Associated Engines
  • Vulcain 2 SEP, Ottobrunn lox/lh2 rocket engine. 1350 kN. In development. Isp=434s. New generator cycle rocket engine for an Ariane 5 core stage upgrade. Thrust increased more than 30% from Vulcain 1. First flight 2002. More...

Associated Launch Vehicles
  • Ariane 5 EC-B French orbital launch vehicle. The ultimate evolved Ariane 5 funded as of the end of the millenium. A larger Lox/LH2 upper stage using the Vinci motor in place of the HM7B. The core remains the same. Result is an increase in GTO payload from 10.5 tonnes to 12.0 tonnes. More...
  • Ariane 5 V French orbital launch vehicle. Version of the evolved Ariane 5 using a version of the EPS storable propellant stage instead of a new Lox/LH2 stage. Result is a payload to GTO of 8 tonnes. The use of the new Aestus restartable engine in the upper stage fitted the vehicle for space station logistics missions or launch of space probes requiring complex orbital maneouvres. More...
  • Ariane 5ECA French orbital launch vehicle, first version of the evolved Ariane 5. The solid booster motors propellant load was increased by 2.43 tonnes and the case was welded, for a weight saving in dry mass of 1.9 tonnes. The core was powered by an improved Vulcain 2 engine. The oxygen-rich cycle of the engine allowed the oxygen bulkhead to be moved within the stage, resulting in a 15.2 tonne increase in propellant in the core. A new Lox/LH2 upper stage, using the HM7B engine and oxygen tank from the Ariane 4 series, replaced the storable propellant EPS stage of earlier models. The result was an increase in payload to geoscynchronous transfer orbit from 6 tonnes to 10.5 tonnes. More...
  • Ariane 5ES Version of the Ariane 5 designed to orbit ESA's Automated Transfer Vehicle (ATV) resupply vehicle for the International Space Station. 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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