Overall sound power levels from four launch vehicles

To better understand the radiated sound from launch vehicles, this paper describes an effort to quantify the overall sound power level (OAPWL) from different launches. The classic NASA SP-8072 report (K. Eldred, 1971) contains data showing OAPWL as a function of mechanical power but little has been published on actual OAPWL since. This paper uses noise data from four different vehicles launched from Vandenberg Space Force Base to examine the relationship between OAPWL and measurement distance from the launch pad. Because OAPWL values calculated from measurements lessen with increased distance, an empirical correction based on nozzle diameter is described. [Work supported in part by NSF.]