Pressure oscillations in post-Challenger Space Shuttle redesigned solid rocket motors

Abstract

Data from the first seven solid rocket motor (SRM) static tests were used to establish upper bounds for the maximum acoustic pressure amplitudes in the latter half of firing. Those bounds have since been used as a basis for worst-case simulation scenarios by specialists in structural dynamics at NASA and Rockwell International, and to provide a basis for evaluating data from individual motors which were tested subsequent to the original seven SRMs. The purpose of this article is to compare current motor data with data from the early motors and determine whether or not the upper bounds need to be recalculated. Comparisons of chamber pressure amplitudes in redesigned solid rocket motors (RSRMs) with the predicted upper bounds, based on the original seven motors, initially suggest that the original bounds are no longer suitable descriptors for the current motor designs. However, a rigorous statistical analysis of the SRM and RSRM motor data indicates that the data are from similar statistical populations.