Low‐Amplitude Sonic Boom From a Descending Sounding Rocket

The target sonic boom shock strength specified in the DARPA Quiet Supersonic Platform project was 0.3 psf. The potential acceptability of that overpressure is based to a large degree on the expected relaxation‐driven shock structure. It has previously been difficult to obtain sonic booms in that range from aircraft, so there had been no flight test data verifying the shock structure of such minimized booms. Low amplitudes do occur, but they are generally near the edge of the boom carpet, are distorted by ground effects, and do not represent the kind of primary boom that is expected from a low‐boom aircraft. Recent flights of sounding rockets have generated low overpressure booms, providing an opportunity to examine weak boom shock structures as they occur under real atmospheric propagation. One extraordinarily clean 0.2 psf N‐wave provided a shock structure which is quantitatively compared with relaxation theory.