EDWARDS AIR FORCE BASE, Calif -- The National Sonic Boom Test project began. This was a joint Air Force, NASA, and FAA study of jet noise and sonic boom effects on structures and people. Two dedicated houses were built and instrumented near Bldg P-1, and a third in Lancaster to catch sonic spillover effects. Repeated supersonic passes by a variety of aircraft recorded data and the effects upon the buildings and some 100 test personnel. The objective of the program was to apply the data to supersonic transport (SST) development.
Shock waves develop simultaneously with supersonic flight in the atmosphere, and the passage of these shock waves over people, animals and structures on the ground cannot be completely eliminated. However, the real concern is for civil supersonic overland flight operations that cause repeated sonic booms over very large areas. The feasibility of routine civil supersonic flight operations and particularly their acceptance by the general public for overland routes may be largely a function of the severity of the sonic boom, but also encompasses a plethora of sociological as well as technological considerations.
A sonic boom does not occur only at the moment an object crosses the speed of sound and neither is it heard in all directions emanating from the supersonic object. Rather the boom is a continuous effect that occurs while the object is travelling at supersonic speeds, but it affects only observers that are positioned at a point that intersects a region in the shape of a geometrical cone behind the object. As the object moves, this conical region also moves behind it and when the cone passes over the observer, they briefly experience the boom.