Softening the Sonic Boom: 50 Years of NASA Research

Lawrence R. Benson

The advent of practical supersonic flight brought with it the shatter­ing shock of the sonic boom. From the onset of the supersonic age in 1947, NACA-NASA researchers recognized that the sonic boom would work against acceptance of routine overland supersonic air­craft operation. In concert with researchers from other Federal and mil­itary organizations, they developed flight-test programs and innovative design approaches to reshape aircraft to minimize boom effects while retaining desirable high-speed behavior and efficient flight performance.

FTER ITS FORMATION IN 1958, the National Aeronautics and Space Administration (NASA) began devoting most of its resources to the Nation’s new civilian space programs. Yet 1958 also marked the start of a program in the time-honored aviation mission that the Agency inherited from the National Advisory Committee for Aeronautics (NACA). This task was to help foster an advanced passenger plane that would fly at least twice the speed of sound.

Because of economic and political factors, developing such an aircraft became more than a purely technological challenge. One of the major barriers to producing a supersonic transport involved a phenomenon of atmospheric physics barely understood in the late 1950s: the shock waves generated by supersonic flight. Studying these "sonic booms” and learning how to con­trol them became a specialized and enduring field of NASA research for the next five decades. During the first decade of the 21st century, all the study, testing, and experimentation of the past finally began to reap tangible benefits in the same California airspace where supersonic flight began.[322]