Prediction and observation of regional infrasound from the OSIRIS REx re-entry capsule

Infrasonic signals produced by bolides and space debris passing through atmosphere are frequently observed at notable stand-off distances. The acoustic energy radiated from such objects is dominated by the aero-acoustic Mach cone which exhibits a highly directional radiation pattern dependent on the velocity of the object relative to the surrounding atmosphere. Recently, a mapping of the Mach cone geometry into acoustic ray tracing methods has enabled efficient regional simulation of infrasonic ensonification from such sources. In September 2023, the OSIRIS REx sample capsule returned to Earth as part of a NASA supported asteroid study and a number of institutions deployed sensors to measure geophysical signatures of the event. The anticipated capsule trajectory was combined with historical atmospheric data for September in the western United States to predict likely regional ensonification during re-entry. Los Alamos National Laboratory infrasound experts deployed microbarometer arrays in locations predicted to be ensonified and were able to identify signals with arrival times and direction-of-arrival consistent with the capsule re-entry. An overview of the predictions, field deployments, and identified signals will be presented.