Ariane 6 Upper Stage Passes Critical Acoustic Testing, Eyes Historic Launch

In a monumental development for Europe’s space ambitions, the upper stage of the Ariane 6 rocket has successfully completed an extensive series of acoustic tests at the European Space Research and Technology Centre (ESTEC) located in the Netherlands. This achievement marks a pivotal step in confirming the rocket's readiness for its upcoming four-booster variant launch, anticipated to be the most powerful iteration of the Ariane 6 yet.

Conducted by the dedicated teams at ArianeGroup, the acoustic tests involved five rigorous evaluations at varying sound intensities to ensure the upper stage's durability against the extreme conditions of a four-booster launch. Prior to these tests, the model had already undergone hot-fire assessments at Germany’s DLR test facility from 2022 to 2024, enhancing its readiness for final evaluations.

The importance of these acoustic tests cannot be overstated, as launching a rocket generates staggering levels of sound energy. To replicate this challenging environment, the Ariane 6 upper stage was subjected to simulations within the Large European Acoustic Facility (LEAF), Europe’s premier acoustic testing center established by the European Space Agency (ESA). This state-of-the-art facility is specifically designed to reproduce the intense auditory conditions a rocket faces at liftoff, allowing engineers to guarantee that the upper stage can withstand the seismic sound waves produced during an actual launch.

The Ariane 6 is engineered with remarkable adaptability, allowing for configurations with two or four boosters tailored to meet varying mission requirements based on payload and orbital destination. Following its successful maiden voyage in July 2024, which featured a two-booster configuration and successfully deployed its payload into orbit, the upcoming four-booster launch in 2025 is expected to generate nearly double the thrust, thereby placing the upper stage under an additional 60% acoustic stress.

At the heart of the upper stage lies the Upper Propulsion Liquid Module (UPLM), designed specifically for the challenges it will encounter. Situated approximately 34 meters above the rocket’s engines, this imposing structure measures over six meters in height and is the heaviest component subjected to testing in the LEAF to date. To replicate the conditions of flight, the module was filled with a carefully balanced mixture of water and glycerine during the evaluations.

Moreover, the test model was outfitted with 200 sensors to meticulously record its performance in response to the strenuous acoustic simulations. To further enhance the realism of the testing environment, black coverings were utilized to replicate the acoustic insulation and intertank structures of the actual rocket. The LEAF facility, with its impressive half-meter-thick walls and robust secure doors, played a crucial role in containing the monumental noise generated during these trials.

As the LEAF facility prepared to conclude the tests, the final scenes showcased the immense chamber with its doors ajar, a testament to the scale and resilience required for one of Europe’s most challenging sound testing endeavors.

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