2023 ASEE Annual Conference & Exposition

The employment of additive manufacturing in the non-standard environments like space, ships, or submarines has the potential to be an advanced utility not only in the pre-flight production of aerospace components and structures, but also for the onboard manufacturing of components and tools necessary for future space missions. For example, the ability to produce tools and structural components on the International Space Station can provide the space community the opportunity to make repairs and upgrades to the space station without wasting time and resources transporting such materials through additional missions. Additive manufacturing would allow for space missions to use on board materials to design and manufacture tools, therefore decreasing the frequency or even reliance of resupply missions.

This paper discusses the experiential learning from engaging in a capstone design project, which would answer the question, "Is it possible to achieve accurate additive manufacturing in a high external load environment such as within a sounding rocket?" With limited research available on additive manufacturing in space, conducting a 3D print on a sounding rocket platform provided valuable information for future such elaborate experiments in space. The additive manufacturing mission parameters were dictated by the 2021 - 2022 RockSat-C program and NASA Wallops Flight Facilities safety requirements. The experiment was conducted within a canister with a height of 4.5 inches and a radius of 9 inches. With these guidelines in mind, the team designed a small form factor FDM Bowden-style PLA 3D printer that would start printing upon rocket launch and be complete upon re-entry. This printer was subjected to 25 – 50 Gs of external force, 10 rev/s, and a vibration test. The printer needed to weigh no more than 4.3 lbs and needed independent power. Most of the structure was 7075 grade aluminum manufactured to support the printer. The power source was a custom 6V lithium polymer battery pack that was converted to a 24V DC to run the printer. Four small stepper motors and belts controlled all printer movement, X and Y-axis movement was mounted on linear rails for accurate motion under high stresses, and Z axis was controlled by a lead screw powered via a belt by one of the stepper motors. The direct drive extruder fed the filament into the micro hot end.

While the experimental setup was not able to credibly demonstrate additive manufacturing in space, the instrument powered ON. It was observed from the outcome of the experiment that there was a need to subject the battery and its circuit, structural components, and the printer head to 50 Gs of force. After the launch of the payload, inspection revealed a stress crack in the PLA motor mount, a loose battery, and filament that was not fed to the hot end. The team was able to see evidence of some extruded PLA and movement of the printer head. If shaft encoders, motor voltage requests, and thermal sensors been used, the team would have been able to “replay” the motions and states the components experienced. This data would have allowed for a troubleshooting process that would have allowed a process to improve the prior design weaknesses. These sensors will be used in the future, therefore mission results can be evaluated and improved upon.