Acoustical measurements of a Delta IV Heavy launch (NROL-82)

Abstract

On 26 April 2021, the BYU Acoustics Research Group made noise measurements during launch of a Delta IV Heavy rocket (NROL-82) from Vandenberg Space Force Base in California. Measurement locations ranged in distance from 330 m to 19 km from the launch pad. Some sensors were arranged in a rough arc of 1i–4 km radius and others were placed along both an east-west line and a north-south line. Because of nearby mountains, some measurement stations were able to be located above the vehicle at the pad. We were therefore able to measure the noise in the different directions and at different distances, spanning a large angular range. This presentation will discuss an overview of noise level, frequency, and temporal characteristics. Additionally, two stations consisted of 5-meter radius, multimicrophone vector probes. Using these probes we were able to track the trajectory of the rocket ascent; our acoustically traced trajectory agrees well with the actual trajectory data. The results of these analyses will be presented.