Acoustic measurement in the static firing tests of solid rocket motors

Acoustic management is essential for establishing a reliable and cost-competitive rocket system. A solid propellant motor during its lift-off imposes high levels of pressure and vibration on the fairing of the rocket, sometimes leading to crucial damage of the payload. One approach to resolve this problem is to decrease the sound sources caused by high-speed plume of the rocket booster. Japan Aerospace Exploration Agency (JAXA), aiming at the advanced solid rocket, started computational prediction that helps design a launch-pad with less acoustic impact. For validating the computation codes and modeling the acoustic characteristics, the experimental acoustic data of solid rocket motors have long been desired. Fortunately, we had opportunities of the ground firing tests with several motors. In this presentation, the acoustic measurement including the sensors, the set-up, and the data reduction carried out in these tests will be discussed.