The 1600m3 Acoustic Test Facility is used to reproduce the acoustic environment inside payload fairing during liftoff and flight, and to confirm and verify that spacecraft can withstand the environment.
The test is conducted in a reverberation chamber, a space where sound reverberates for a long time and is surrounded by thick concrete to reduce the sound absorption by the walls. The extremely powerful sound source consists of 7 electro-pneumatic transducers and one pair of jet nozzles, and the sound power reaches 70 kW in total. The high-pressure nitrogen gas supplied to the electro-pneumatic transducers and jet nozzles is produced by heating and evaporating the liquid nitrogen in an outdoor gas generator and is then released indoors from the outlets of the 25 Hz, 100 Hz, and 200 Hz horns and jet nozzles.
The sound recorded by 4 to 6 control microphones inside the reverberation chamber is subjected to frequency analysis, and the required acoustic load is applied to the test specimen by automatically controlling the output of each sound source to match the target frequency spectrum.
