Energy-based acoustic measurement system for rocket noise

Abstract

Accurate estimates of the vibroacoustic loading placed on space vehicles and payloads during launch require knowledge of rocket noise source properties and near-field acoustic energy flow characteristics. Without these data, structures may not be designed to handle the correct vibroacoustic loads, which can result in either an over-built, excessively massive structure or an under-designed vibration mitigation system that could result in damage to payloads. These measurements are difficult to perform because of the extreme nature of the acoustic and temperature environments near the rocket plume as well as the large physical size of the rocket noise source. With these design constraints in mind, a field-deployable data acquisition system and energy-based measurement probe have been developed to measure the magnitude, directivity, and spectral content of the rocket source. Initial measurements with various prototypes were conducted during a static test fire at ATK Space Systems Test Services in Promontory, Utah with limited results presented here. [Work sponsored by NASA John C. Stennis Space Center.]