Measurements of rocket landing sonic booms from three SpaceX Falcon-9 booster landings Free

As commercial rocket companies reduce costs, a common strategy is to design reusable rockets. The recovery typically includes propulsively landing the first stage booster near the launch site or on an ocean platform. Because the booster returns at supersonic speeds, a sonic boom is produced. This paper analyzes measurements made of three SpaceX Falcon-9 booster landings at Vandenberg Space Force Base. Each measurement uses multiple microphones surrounding the launch and landing pads at distances varying between 300–25 000 m. The Falcon-9 sonic boom waveforms have three shocks, and all three are consistently measured at every single measurement location. Although the rise times increase with distance, the duration between the shocks shows a more complicated trend, with the farthest measurements sometimes having the same duration as the nearest measurements. Farther than 1 km, the sonic boom peak overpressure can exceed the peak launch noise overpressures. Farther than a few kilometers, the sound exposure level from the sonic booms can be comparable to the exposure during the entire 12 dB-down period for the launch noise. [Research funded in part by the Oak Ridge Institute for Science and Education and Vandenberg Space Force Base.]