Turbulence-induced variability of a far-field Falcon-9 sonic boom measurement

Although aircraft sonic booms have been researched for decades, sonic booms from rocket booster landings are relatively recent events that are less studied. However, as booster landings become more prevalent, a better understanding of the associated sonic booms and community impact is needed. Atmospheric turbulence distorts sonic boom waveforms, affecting both the rise time and peak pressure, and can have a large impact on human perception metrics. As an initial investigation into the impact of turbulence on sonic boom measurements, measurements were made of the reentry sonic boom during the SpaceX Falcon-9 SDA Tranche 0B mission at Vandenberg Space Force Base, California. An 11-microphone linear array spanning 150 m (500 ft) recorded the boom 8.5 km from the landing pad. This paper discusses results from this measurement, including variability of human perception metrics. For example, Perceived Level varied by up to 8 dB across the array. Work supported through a NASA Graduate Research Fellowship.