Rocket motors and methods of manufacturing rocket motors

A method of making a modular rocket motor, the modular rocket motor comprising:

• a. a composite case having a forward end and an aft end;
• b. wherein the forward end has a radial retention interface, the radial retention interface comprising a multi-stack polar boss, multi-stack forward polar boss enclosure, and radial tabs numbering between three and twenty;
• c. wherein the multi-stack polar boss is molded with boss molding material into said radial tabs;
• d. wherein the multi-stack polar boss is wound into the composite case;
• e. wherein a plurality of multi-stack cartridges houses a propellant and a central combustion chamber;
• f. wherein the plurality of multi-stack cartridges are suspended inside the composite case, the plurality of multi-stack cartridges comprising at least a forward cartridge, a primary cartridge, and an aft cartridge;
• g. wherein the plurality of multi-stack cartridges are secured in fitted engagement by a plurality of joints, and wherein the plurality of multi-stack cartridges are retained co-axially with the composite case;
• and
• h. wherein the aft cartridge is located at the aft end of the composite case, and wherein the aft end has a closure and a nozzle, the method comprising the steps of:
• 1. cure hard plastic of an extended case at a temperature of at least 310 F;
• 2. mold a charging gap and the multi-stack polar boss using the boss molding material, wherein the multi-stack polar boss is molded into at least three of the radial tabs, and wherein the radial tabs are located on the forward cartridge;
• 3. add ethylene propylene diene monomer (EPDM) to the face of the multi-stack polar boss to form a multi-stack polar boss pre-mold;
• 4. adding the multi-stack polar boss to a mandrel and laying up EPDM sheets over a forward cartridge resin;
• 5. laying up a fiberglass fabric sheet over uncured EPDM to form the EPDM sheets;
• 6. laying the EPDM sheets over the mandrel, and laying fiber glass pre-preg sheets over the mandrel;
• and
• 7. wherein a radial tab clearance to an igniter EPDM comprises a diameter of 0.65 inches to 0.85 inches, and wherein the radial tab clearance has a charging gap of between 0.02 inches and 0.05 inches.