A look into far-field rocket noise modeling: Approaches and potential sources of error

Abstract

In recent years, rocket launches have elevated from novelty to being seen as means of transportation, exploration, and delivery. Defense, commercial, and public sectors are looking to increase their cadence in missions and ability to perform them. Like airports before them, spaceports are being developed and regulated. Much research has been done in rockets as a noise source, and how they may affect communities, structures, and wildlife. The most common approach for modeling the far-field rocket noise relies heavily on NASA SP-8072 and work done by Dr. Sally McInerny, a NASA researcher. The approach takes known mechanical properties of the rocket, such as rocket nozzle diameter, exit flow velocity, and number of engines to calculate the sound power of the system, and then propagate the noise to the receiver with an applied directivity factor. The level decay is based on spherical spreading, and additional attenuation factors such as atmospheric conditions and ground impedance. This paper attempts to show an overview of these different components and their effects on model predictions. Their relevance and limitations are also discussed.