Dispersion Reduction for a Sounding Rocket Scramjet Flight Experiment

Abstract

A low cost method for reducing the dispersion in the trajectory of an unguided, spinstabilized, sounding rocket is developed and presented. The method is particularly suited to scramjet flight experimentation because the approach increases the likelihood of meeting Mach number and dynamic pressure objectives. The paper discusses the design and model of the scramjet payload, and two-stage launch vehicle, and the nominal trajectory, as well as a Monte Carlo analysis to quantify the likelihood of a successful scramjet test. Using the results of this analysis, a method is presented for reducing the dispersion in freestream conditions during the scramjet test window. The dispersion reduction is accomplished by modifying the time delay between the burnout of the first stage booster and the ignition of the second stage based on the vehicle state measured during the interstage coast. This method increases the likelihood of a successful test from 71% to 99% without adversely affecting range safety. Since the design and implementation of a vehicle guided control system is not required, this method is relatively inexpensive, making its use highly desirable for low cost scramjet flight experimentation.