Editing Launch pad (section)

=== Sound suppression systems ===
{{main|Sound suppression system}}
Sites for launching large rockets are often equipped with a sound suppression system to absorb or deflect [[Sound|acoustic energy]] generated during a rocket launch.  As engine exhaust gasses exceed the [[speed of sound]], they collide with the ambient air and [[Shock wave|shockwaves]] are created, with noise levels approaching 200 db. This energy can be reflected by the [[Transporter erector launcher|launch platform]] and pad surfaces, and could potentially cause damage to the launch vehicle, payload, and crew. For instance, the maximum admissible overall [[sound power]] level (OASPL) for payload integrity is approximately 145 db.<ref>Dougherty, N. S., &amp; Guest, S. H. (2012, August 17). A correlation of scale model and flight aeroacoustic data for the Space Shuttle Vehicle. ''Aeroacoustics Conferences''. Retrieved November 16, 2022, from https://arc.aiaa.org/doi/10.2514/6.1984-2351</ref> Sound is dissipated by huge volumes of water distributed across the launch pad and launch platform during liftoff.<ref name=":0sss">{{Cite journal|last=Lubert|first=Caroline Parsons|date=2017|title= Sixty years of launch vehicle acoustics|journal= The Journal of the Acoustical Society of America|volume=142|issue=4 |page=040004|doi=10.1121/1.5014084|bibcode=2017ASAJ..142.2489L|doi-access=free}}</ref><ref>{{Cite journal|last1=Walsh|first1=E. J.|last2=Hart|first2=P.M.|date=Nov 1982|title=Liftoff Ignition Overpressure-A Correlation|journal=Journal of Spacecraft and Rockets|language=en|volume=19|issue=6|pages=550–556|doi=10.2514/3.62300|bibcode=1982JSpRo..19..550W|issn=0022-4650}}</ref>

Water-based acoustic suppression systems are common on launch pads.  They aid in reducing acoustic energy by injecting large quantities of water below the launch pad into the exhaust plume and in the area above the pad. [[Flame deflector|Flame deflectors]] or flame trenches are designed to channel rocket exhaust away from the launch pad but also redirect acoustic energy away.<ref name=":0sss" /><ref>{{Cite web|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710023719.pdf|title=Acoustic Loads Generated by the Propulsion System (NASA SP-8072)|last=|first=|date=June 1971|website=|access-date=}}</ref>