Commercial Space Operations Noise and Sonic Boom Measurements (2020)

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Commercial Space Operations Noise and Sonic Boom Measurements 92 5 Conclusions and Suggested Research The purpose of this research project was to develop a well-documented, high-fidelity database of acoustic measurements of commercial space operations that were acquired using a consistent data collection and analysis protocol. First, a survey of historical measurements was performed to assess the availability, quality, and limitations of existing acoustic datasets in relation to the objectives of this research effort. Unfortunately, none of the surveyed datasets within the existing body of literature provide high-quality acoustic, operational, and meteorological data. Nevertheless, the existing datasets were compiled into an organized database. Insights gathered from the literature review were leveraged to develop a community noise measurement protocol that defines measurement methods and documentation procedures for obtaining accurate, reliable, and repeatable noise data for commercial space operations. The protocol was applied during a measurement campaign to collect acoustic, operational, and meteorological data from four different commercial space vehicle launch operations, one of which also included return-to- landing operations. The propulsion noise and sonic boom measurements acquired during these events were combined with the operational and meteorological data and compiled into a database. The resulting database consists of well-documented, high-fidelity acoustic measurements with the supporting data necessary to validate community noise models for space transportation operations. The historical and high-fidelity acoustic databases will be disseminated as a result of this research effort, which marks the first time that reliable, comprehensive propulsion noise and sonic boom measurements from a diverse set of launch vehicles and events have been made available to the public. These datasets will be useful to researchers, regulatory bodies, and dual-use airport and spaceport personnel for conducting follow-on studies and making well-informed decisions regarding community noise impacts. However, both decision makers and the general public would derive the most benefit from this research effort if the acoustic databases are applied to improve the models used to predict community noise exposure from space transportation operations. Currently, the Aviation Environmental Design Tool (AEDT) is the only noise model that is approved by the FAA for use in environmental reviews, which are required as part of the licensing process for all new spaceports and launch vehicles. However, AEDT does not include standard data or methods for evaluating the propulsion noise from commercial space operations. Since there is currently no FAA-approved noise model for commercial space operations, special approval is required from the FAA Office of Environment and Energy (AEE) for every environmental document that uses a non-standard noise modeling methodology. Thus, a follow-on effort is needed to leverage the data collected during this research project to improve and validate the rocket propulsion noise and sonic boom models developed under ACRP Project 02-66, “Commercial Space Operations Noise and Sonic Boom Modeling and Analysis.” Once they are validated, the rocket propulsion noise and sonic boom models would be eligible to be officially “approved” by AEE and could then be integrated into AEDT using the AEDT integration plans proposed under ACRP Project 02-66. The FAA Office of Commercial Space Transportation (AST), AEE, and dual-use airport and spaceport operators have a particular interest in implementing this research to develop and validate FAA-approved propulsion noise and sonic boom models for commercial space operations. The community noise measurement protocol developed under this research effort defines measurement methods and documentation procedures for obtaining accurate, reliable, and repeatable propulsion noise

Commercial Space Operations Noise and Sonic Boom Measurements 93 and sonic boom data for commercial space operations. The protocol will be instrumental in collecting high-quality noise data for new types of operations and vehicles, such as rocket planes and small launch vehicles, that are currently under development. Future efforts are recommended to formally vet the community noise measurement protocol through the use of a standards organization such as the American National Standards Institute (ANSI), American Society for Testing and Materials (ASTM), or Society of Automobile Engineers (SAE). Ultimately, the research conducted under this project will lead to improved rocket propulsion noise and sonic boom models that represent the best available science. The validated noise predictions generated by these models will provide highly accurate information to decision makers and the general public regarding the potential community noise impacts from commercial space operations.