Overcoming Ariane’s quirks and foibles

Letters patent of nobility for Ariane 5

When the Ariane 5 version stepped onto the stage, Europe had dressed itself in the height of fashion in terms of hydrogen-oxygen propulsion (cryogenic propellants) which is also environmentally clean. The main stage of the European heavy-lift launcher is powered by the powerful Vulcan engine. The behaviour of the liquid oxygen in the turbopump’s cogs, developed by Avio, an Italian company, required close attention as problems have occurred in terms of air-tightness and reliability. In particular the air-tightness of the cryogenic valves produced by the Techspace Aero company for the Vulcan booster needed to be scrutinised. At stake were the performances and costs of Ariane 5 in terms of its commercial running and viability. ESA and the CNES thus once again appealed to the EMT department at the University of Liège for help.


In 2001 public investment of around two million Euros allowed to EMT to fit out its cryogenic technology test site, which takes up 4,000 m² of an isolated area on the Sart Tilman campus. The infrastructure – made secure through the installation of a bunker – was designed by Professors Albert Germain and Jean Bozet with the help of Jean-Luc Bozet. Within this site has been brought to completion the test rig for the rotations of the oxygen turbopump of the present HM7B booster. It consists of two tribometers, which test the compatibility of materials with liquid oxygen, as well as an engine with adaptable front bearing casings, towards which the MAN Technologie company provided a financial contribution in order to test hybrid front bearing casings for the rocket propulsion of the future. Its role goes beyond the context of spatial systems. Equipped to evaluate the conduct of materials at very low temperatures, it is made available to any company or business that require the handling or use of cryogenic fluids such as oxygen or nitrogen in a liquid form.

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