Large European Acoustic Facility

This is the most powerful sound system in Europe – but no human being could survive hearing it at maximum output.

Engineer Kees van Zijtveldt is standing beside the largest sound horn of ESA’s Large European Acoustic Facility (LEAF), capable of subjecting satellites to the same noise a launcher produces as it takes off and flies through the atmosphere.

LEAF is an integral part of ESA’s ESTEC Test Centre in Noordwijk, the Netherlands, a collection of spaceflight simulation facilities under a single roof. One wall of the chamber – which stands 11 m wide by 9 m deep and 16.4 m high – is embedded with a set of enormous sound horns. Nitrogen shot through the horns can produce a range of noise up to more than 154 decibels, like standing close to multiple jets taking off.

As a safety feature, LEAF can operate only once all the doors are closed. Steel-reinforced concrete walls safely contain its noise, coated with epoxy resin to reflect noise to produce a uniform sound field within the chamber. The chamber itself is supported on rubber bearing pads to isolate it from its surroundings.