Michael Najjar photographs the Vulcain 2 rocket engine in France
In July 2016 Michael Najjar went to Vernon and Les Mureaux in France to take pictures of the assembly of the Vulcain 2 engine and its integration in the Ariane 5 launcher main stage. Vulcain rocket engines have been used since 1996 to propel Ariane 5 rockets in their first ten minutes of flight, up to an altitude of 200 km. Overall, they provide 8% of the total thrust needed at liftoff, and the full thrust of the propulsion phase after booster separation and before ignition of the upper stage. The Vulcain is ignited by three pyrotechnic devices on the launch pad; six seconds later the solid rocket boosters are ignited and the rocket lifts off.
The engine measures 3m high, 1.76m in diameter, weighs 1,686 kg and is located at the centre of the base of Ariane 5. It delivers 115 tonnes of thrust, achieving this by mixing two cryogenic liquids: hydrogen at –251°C and oxygen at –184°C. Connected to the Vulcain are tanks holding 25 tonnes of liquid hydrogen and 130 tonnes of liquid oxygen. These cryogenic propellants are channelled into the Vulcain’s high-pressure combustion chamber via two turbo pumps. Hydrogen bursts into flame on contact with oxygen inside this chamber in a chemical reaction that generates very hot combustion gases which are expelled by gas expansion through the nozzle at supersonic velocities higher than 4,000 m/s, giving the needed thrust to the launcher.