Sound suppression technology research at Marshall Space Flight Center
This report describes some of the development tests conducted at Marshall Space Flight Center on sound suppressor models. These devices are designed to reduce the sound radiated into the atmosphere from the exhaust jets of large rocket engines. From theoretical considerations, the overall sound reduction capability of the tested models was expected to amount to 40 decibels. However, residual sound, radiated from the rocket engine and its installation, limited the attainable overall suppression to 24 decibels. Suppression of very low sound frequencies remains a special area of endeavor in future investigations. The models were designed to be self-contained. They proved to possess very good operational characteristics.
ROCKET ENGINE NOISE↗