Resumen de Acoustic noise reduction methods for the launch pad

Iván Herrero Durá

• The sound pressure levels experienced by space vehicles during the initial stages of launch (engine ignition and lift-off) are extremely high and can significantly affect light transported structures, such as solar panels and antennas. The intense sound generated by the primary sources, the engine and the jet, is reinforced by the reflection at the bottom of the gas evacuation channel, which acts as a mirror from the acoustic point of view, and returns the energy released directly to the rocket and the structures it carries. This large amount of energy can put some launch missions at risk, with the economic and security consequences that this entails. Despite the relevance of this problem, knowledge about the characteristics of the sources, the behavior of ground facilities in reference to the dispersion, diffusion and absorption of sound, and the possible measures to mitigate the impact is still scarce. In this context, the main objective of this thesis will be developed. The purpose of this work is the design and optimization of a prototype system based on an array of Helmholtz resonators to maximize the absorption and dispersion of sound at ground level and, in this way, mitigate the sound pressure levels generated in these events in the aerospace context. The work of this thesis has been carried out within the framework of the Networking/Partnership Initiative contract 441-2015 of the European Space Agency.