Flyback sonic booms from Falcon-9 rockets: Measured data and some considerations for future models Free

The SpaceX Falcon-9 rocket is a partially-reusable vehicle with a first-stage booster that lands propulsively after launch. As the booster falls toward the landing site, it produces a sonic boom. These sonic booms have unique properties and, so far, the ability to model them using current methods remains unclear. This paper presents findings from three Falcon-9 flyback sonic booms and highlights some features and trends that will be important to future modeling efforts. At every measurement location, a triple boom is recorded. This triple boom appears to propagate stably to at least 25 km from the landing pad. Within 1–2 km of the landing pad, the calculated sonic boom metrics tend to plateau. Outside 1–2 km of the launch and landing facility, the sonic boom is the highest-pressure event of the entire flight, including the launch. The Perceived Level 1 km from the landing pad is around 128 dB and at 25 km is around 87 dB. An appendix is included that discusses the benefits and challenges of attempting to correct for hardware low-frequency rolloff using digital pole-shift filtering.