Vortex cooled thermoplastic chamber thruster for potential application to polymer based 3D printed space propulsion systems

Abundant carbon dioxide (CO₂) on Mars could serve as a valuable resource for in-situ resource utilization, with its potential conversion into plastics for space manufacturing. This study investigates the feasibility of a vortex-cooled thermoplastic combustion chamber thruster, designed to support polymer-based 3D-printed propulsion systems for future space missions. A preliminary test was conducted using a thermoplastic combustion chamber thruster featuring cooling capabilities. A swirl type oxidizer injection was implemented within the chamber, where a portion of the oxidizer participated in the combustion reaction, while the remainder flowed along the inner surface of the thermoplastic combustion chamber to provide cooling. This was applied to a 10 N class bipropellant thruster using propane and gaseous oxygen and experimentally tested to determine the viability of forming a stable cooling layer along the chamber wall. Through extensive firing tests, the effects of injection configuration and mass flow rate on vortex cooling performance were investigated. The cooling layers were successfully formed, providing sufficient thermal protection for the plastic chamber, while maintaining a combustion flame in the middle of the chamber at a temperature exceeding the ignition point of the chamber material. The thruster propulsion performance in terms of a characteristic velocity efficiency was greater than approximately 80% in each test, with different injection configurations considered. These preliminary results suggest possible applications of vortex cooling in polymer-based 3D-printed propulsion systems, potentially advancing additive manufacturing technologies for sustainable and adaptable space propulsion.