A Throttling Solid Propellant Rocket Motor with Adaptive Thrust Control

An innovative nozzle concept is proposed to enable variable thrust solid rocket motors to operate with minimal loss in efficiency over a wide thrust range. The proposed approach will also allow commanded near-extinguishment of the motor, and more controllable start transients. The approach will be compatiable with an adaptive control system to allow closer adherence to a specified mission profile. A Phase I program is proposed which will evaluate the concept using CFD analysis and produce an optimized approach for a development test program to be conducted in Phase II. Pintle design concepts have been applied in the past with limited success. The proposed design addresses the problem areas identified in previous solid motor variable thrust programs. By applying technologies used in other applications, the Phase I objective will be to determine the feasibility of variable thrust solid motor operations with higher performance throughout the thrust range by providing convincing evidence that the technical issues can be resolved. Phase II will demonstrate the feasibility by conducting component and engine testing, final design, and prototyping of a development system suitable for production design culminating in a demonstration test of the development hardware.