Falcon-9 ascent sonic boom measurements in Ventura County, California

Motivated by resident complaints and potential environmental concerns, measurements of Falcon-9 sonic booms created during vehicle ascent were collected in Ventura County, California. These booms are often low-frequency events that rattle structures, similar to earthquakes. During Summer 2024, a total of 132 measurements across six launches (16–25 per launch) were collected, spanning an area of ∼200 square miles (∼500 square km). The launches, from Vandenberg Space Force Base around 80–90 miles (130–145 km) to the north, varied by time of day, weather conditions, and trajectory. Described in this paper is the measurement campaign as well as initial results that include maps of peak overpressure values. Perceived level is also calculated to compare Falcon-9 ascent booms to aircraft sonic booms and other transient sounds. The roles of launch azimuth and weather in explaining ascent boom variability are discussed. This measurement campaign represents an important baseline for a broader effort spanning multiple seasons and a greater number of launches. [Work supported by USSF through USACE.]