Vulcain (rocket engine)

Vulcain is a family of european cryogenic first stage rocket engines for the Ariane 5.

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History

The development of Vulcain, assured by a European collaboration, began in 1988 with the Ariane 5 rocket program. ^[1] It first flew in 1996 powering the ill-fated flight 501 without being the cause of the disaster, and had its first successful flight in 1997 (flight 502). In 2002 the upgraded Vulcain 2 with 20% more thrust^[2] first flew on flight 517, although a problem with the engine turned the flight into a failure. ^[3] The cause was due to flight loads being much higher than expected, as the inquiry board concluded. ^[4] Subsequently, the nozzle has been redesigned, reinforcing the structure and improving the thermal situation of the tube wall, enhancing hydrogen coolant flow as well as applying thermal barrier coating to the flame-facing side of the coolant tubes, reducing heat load. The first successful flight of the (partially redesigned) Vulcain 2 occurred in 2005 on flight 521.

Future development

Although different upgrades to the engine have been proposed^[5], there is no current program to develop an uprated version of the engine. If there will ever be one, it is likely that the new engine would be introduced after the "PA batch" of 30 Ariane 5 ECAs ordered on 10 May 2004^[6][7] will be expended.

Overview

The Vulcain engines are gas-generator cycle cryogenic rocket engines fed with liquid oxygen and liquid hydrogen. They feature regenerative cooling through a tube wall design, and the Vulcain 2 introduced a particular film cooling for the lower part of the nozzle, where exhaust gas from the turbine is re-injected in the engine ^[4] They power the first stage of the Ariane 5 launcher, the EPC (Étage Principal Cryotechnique, main cryogenic stage) and provide 8% of the total lift-off thrust^[10] (the rest being provided by the two solid rocket boosters). The engine operating time is 600 s in both configurations. ^[8] 3 m tall and 1.76 m in diameter, the engine weights 1686 kg and provides 137 t of thrust in its latest version ^[11]. The Italian-built oxygen turbopump rotates at 13600 rpm with a power of 3 MW while the hydrogen turbopump rotates at 34000 rpm with 12 MW of power. The total mass flow rate is 235 kg/s, of which 41.2 kg/s are of hydrogen.

Contractors

The main contractor for the Vulcain engines is Snecma Moteurs (France), which also provides the liquid hydrogen turbopump. The liquid oxygen turbopump is responsibility of Avio (Italy), the gas turbines that power the turbopumps and the nozzle are developed by Volvo (Sweden). ^[10]

See also

• Spacecraft propulsion

Comparable engines

• RS-68

References and notes

Related news

• EADS N.V. - EADS welcomes contract signature for 30 Ariane 5 launchers at ILA 2004 in Berlin
• Three billion Euros contract for 30 Ariane 5 launchers — EADS Astrium