The Future for Solid Propellant Rockets

Abstract

Ten years ago it seemed that the solid propellant rocket engine could make only a limited contribution to rocketry. Although it was simpler and more compact than its liquid propellant rival it suffered from three serious drawbacks. The nozzle was uncooled and so the burning time had to be short, the entire propellant container was subjected to the full combustion pressure and temperature and therefore the inert weight of the engine was high and, since the specific impulse of solid propellants is in general lower than that of liquid propellants (because solids are partially reacted systems) the engine performance was consequently poor, and finally, no means were available for controlling the magnitude and duration of the rocket thrust. These facts were the foundation of the opinion, still held by some people, that solid propellant engines were only suitable as boosters or short burning time sustainers for small missiles.