The present invention comprises a direct replacement for a charge support spacer currently used in rocket motors. The present invention comprises a vented spacer that cools combustion gases through contact and expansion prior to equalizing pressure by transferring these gases from the inside of the propellant grain to the outside of the grain. The vented spacer takes gases from combustion of the propellant from the core flow inside the propellant grain and cools these gases by contact with and ablation of the spacer material. The gases are cooled to the point that they present no hazard to the rocket motor casing or the outside of the propellant grain. The vented spacer accomplishes these tasks in the same amount of area as the current charged support spacer.

A circular slit plate having slits therein that are symmetrically positioned and originate near the center of the plate and extend radially toward the outer diameter thereof is used to deaerate solid rocket motor propellant and to provide a uniform propellant flow distribution during rocket motor casting.

A typical rocket motor includes a motor casing containing a cast propellant onded to the casing and provided with a port through which combustion gases are delivered to the motor nozzle. During storage and operation, mechanical stresses in the propellant may produce tears resulting in motor malfunctions. Tear strength can be increased by reactively forming on selected port surface areas a thin-film cross-linked polymeric gel coating formed essentially of a highly functional polyglycol adipate and a polyfunctional isocyanate. Cross-linking with the propellant can be achieved by controlling the hydroxyl to isocyanate ratios of the coating and the propellant. The coating is particularly useful on XLDB (cross-linked, composite-modified double base) and on CMDB (composite-modified double-base) propellants.

In a rocket motor having an insulative coating on selected portions of the xterior casing, one or more ribs are used to structurally strengthen portions of the casing and to reinforce thermal stress patterns which will cause failure venting at a predetermined point of the rocket motor as a cook-off safety feature.

A solid propellant rocket motor of gas generator of the type having retractable filaments embedded in the propellant for the purpose of controlling the overall thrust or mass flow output is combined with a channeled separator located between the propellant and its casing with the channels open to the combustion chamber. This results in distribution of combustion chamber pressure and temperatures over the exterior of the propellant grain so that distortion of the grain will not occur sufficiently to cause binding or sticking of the filament in their holes in the propellant nor will the holes be enlarged to cause uncontrolled burning between the filament and the hole.