Vulcain 2 Rocket Engine – Thrust Chamber – The latest version of the Ariane 5 cryogenic propellant core stage engine.

The latest version of the Ariane 5 cryogenic propellant core stage engine.

Vulcain 2 Rocket Engine
Vulcain 2 Rocket Engine

Vulcain 2 is a gas generator cycle rocket engine that powers the Ariane 5 ESC-A core stage.

As with Vulcain 1, the Ottobrunn facility of EADS Astrium is responsible for the development and production of the Vulcain 2 thrust chamber comprising:

  • Cardan (gimbal joint, connection to the stage; manufactured by MT Aerospace).
  • Injector head.
  • Combustion Chamber (regenerative cooling circuit).
  • Nozzle Extension (active cooled by dump flow, manufactured by Volvo Aero Corporation).


The Vulcain 2 thrust chamber assembly is supplied to Snecma, France, who are responsible for the integration and delivery of the complete engine.

Developed as part of ESA’s Ariane 5 Evolution Programme, Vulcain 2 introduces an improved Injector design, increased combustion chamber pressure and a modified nozzle extension design. These improvements enable Vulcain 2 to provide Ariane 5 with 30% more power compared to its predecessor. This performance increase, together with the use of the HM-7 engine on the upper stage, enables a payload gain from 6 tonnes on the generic version of Ariane 5, to 10 tonnes on the Ariane 5 ECA.

Today, Vulcain 2 is used in the ECA and ES ATV versions of Ariane 5. In the future Vulcain 2 is also planned for use with Ariane 5 ME, which will introduce the new upper stage Vinci engine (currently under development).

Vulcan 2 was first qualified on Ariane 5 ECA flight 164, launched on 12 February 2005.

One of the most spectacular flights using a Vulcain 2 engine was the successful launch of the Automated Transfer Vehicle, Jules Verne, on 9 March 2008.

New Thrust Chamber Design

Vulcain 2 injector assembly
EnlargeVulcain 2 Injector Assembly
566 coaxial injector elements

Based on the proven technology of its predecessor, the Vulcain 2 thrust chamber was completely redesigned with a number of new, and quite challenging features:

Firstly, the injector head was updated and adapted to the higher flow rate. A second feature is a new Vulcain 2 thrust chamber liner design.

The main design change from Vulcain 1 to Vulcain 2 is the turbine exhaust gas injection into the main flow of the Vulcain 2 engine. This enhancement will increase the performance of the engine by approximately 2 sec.

The coaxial injector element design enables a highly efficient mixing of the LOX and LH2 propellants. These propellants are mainly atomised and mixed by shear forces generated by the velocity differences between LOX and LH2. Although the injector design is complex, it does assure consistent and reliable combustion efficiencies greater than 99%, which are reached during the remaining process in the combustion chamber.

The final acceleration of hot gases, up to supersonic velocities, is achieved by gas expansion in the nozzle extension, thereby increasing the thrust.

Vulcain 2 Thrust Chamber Characteristics
Propellants LOX / LH2
Thrust vac 1,359 kN
Specific Impulse vac. 429 s
Propellant mass flow rate at thrust chamber inlet
– LH2
– Turbine exhaust gas (injected in Nozzle)
40.9 kg/s
275.6 kg/s
10.1 kg/s
Thrust chamber inlet conditions
– LH2 Pressure
– LH2 Temperature
– LOX Pressure
– LOX Temperature
182.1 bar
36.0 K
153.9 bar
96.7 K
Mixture ratio (TC) 6.7
Combustion Chamber pressure 117.3 bar
Nozzle area ratio 58.2
Nozzle exit diameter 2.09 m
Overall engine length 3.44 m
Thrust Chamber mass 909 kg


Vulcain 2 Brochure



Click here to download the Vulcain2.pdf brochure.

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