Autonomous measurement of space shuttle payload bay acoustics during launch

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Authors
Boyd, Austin W.
Kosinski, Brian P.
Weston, Richard L.
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Date of Issue
1987
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Office of Naval Research
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Abstract
A method of recording and analyzing the acoustic characteristics of the Space Transportation System (STS) cargo bay has been developed . The experiment is integrated within a NASA Get-Away-Special (GAS) canister. The experimental procedure involves an autonomous prelaunch measurement of acoustic modes using an oscillator, loudspeaker, and three microphones. Acoustic-resonance data are recorded on a solid-state digital recorder using magnetic bubble-memory. The system is then used to record ambient noise prior to and during the launch. Postflight data analysis will provide information relevant to the design of sensitive spacecraft components. Airborne acoustic vibrations, like structure-borne mechanical vibrations, possess the potential to cause significant damage to payloads aboard the Space Shuttle. Early flights of the orbiters confirmed that such vibrations contributed to the loss of thermal protection tiles and subsequent minor vehicle damage. Similar distress in sensitive spacecraft components has been of continuing interest to contractors and NASA, as components are engineered to withstand the rugged mechanical vibrations and intense sound pressure levels (135 dB SPL) experienced during launch. The Dynamic Acoustic and Thermal Environments (DATE) group of NASA Goddard Space Flight Center and the Aerospace Corporation of El Segundo, CA, have been analyzing data from STS missions. Two conclusions reached by these groups are that a better understanding of the STS cargo bay acoustics is needed and that the acoustics data base should be expanded. Additionally, a more precise analysis is required with regard to the acoustic transients produced at the moment of solid rocket booster (SRB) ignition. The acoustic impulse generated by the igĀ­nition of the boosters could be a significant damaging force, but previous experiments have experienced difficulty in characterizing it quantitatively. An analysis of booster ignition acoustics may also provide insight into failure mechanisms of that critical Shuttle component.
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Article
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Space Systems Engineering
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9 p.
Citation
A.W. Boyd, B.P. Kosinski, R.L. Weston, "Autonomous measurement of space shuttle payload bay acoustics during launch," Naval Research Reviews, no. 1, (1987), pp9-17
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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