The acoustic test facility is used to conduct tests to confirm the functions and structural robustness of a spacecraft in a simulated interior acoustic environment of a launch vehicle fairing during the launch and flight stages.
The test room called a “reverberation chamber” is enclosed by thick concrete walls to minimize the acoustic absorptivity on them. The acoustic source is composed of seven electro-pneumatic transducers and one jet nozzle, which can generate the acoustic power of about 70 kW. The high-pressure GN2 supplied to the electro-pneumatic transducers and the jet nozzle derives from LN2 heated and evaporated in the outdoor GN2 system, to be effectively blasted out of the air outlets of horns for 25 Hz, 100 Hz, and 200 Hz, and the jet nozzle, into the reverberation chamber.
The target sound pressure for a test is loaded on a test item (sound application) after frequency analyses and automatic controlling are performed on the sound collected by 4 to 6 microphones installed on stands and deployed in the chamber to match its acoustic field (the diffusion of sound) to the required sound pressure spectrum.
