First Detection of Firework‐Generated Infrasound in the Upper Mesosphere–Lower Thermosphere With a Rocket‐Borne Sensor: Results From the MOMO3 Sounding Rocket Experiment

Abstract We present the first direct detection of firework‐generated infrasound in the upper mesosphere and lower thermosphere using a rocket‐borne sensor. A wideband capacitive differential pressure sensor (INF03D) was installed on board the MOMO3 sounding rocket, a privately developed vehicle launched from Taiki, Hokkaido, Japan, in May 2019, which reached a maximum altitude of ∼113 km. Ten spherical fireworks were launched from the ground before and after liftoff to provide temporally tagged acoustic sources. Here, denotes the rocket launch time ( s), and all time stamps are given relative to launch unless otherwise stated. Three‐dimensional ray‐tracing simulations were performed with four atmospheric profile sets (NRLMSISE‐00/HWM14, JAWARA, ERA5, and MERRA‐2) to evaluate spatiotemporal intersections between acoustic ray paths and the rocket trajectory. Four distinct pressure transients with Hilbert‐envelope amplitudes of 1.0–2.8 Pa were detected at 50–76 km during ascent, falling within the modeled arrival windows for the T‐30 s and T‐90 s shots. In addition, two weak peaks (∼3.8 mPa each) were observed at 106–109 km during descent, coinciding with a predicted intersection window and classified as marginal hits due to their limited signal‐to‐noise ratios (SNR). Additional ascent‐phase transients around T+170–T+185 s lacked corresponding ray–rocket intersections, suggesting unmodeled propagation or non‐firework sources, and telemetry loss after T+282 s prevented evaluation of late‐descent signals. These findings demonstrate that 0.1–2 Hz infrasound from near‐surface explosions can propagate to over 100 km altitude and that rocket‐borne sensors provide an effective platform for in situ acoustic measurements in the middle and upper atmosphere.