Design, Analysis, Test, and Model Correlation of a Flight-Like Additively Manufactured ESPA-Class Satellite

This paper presents the design, finite element analysis, dynamic testing, and model correlation of AdditiveSat, an additively manufactured Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA)–class spacecraft fabricated using fused filament fabrication. The AdditiveSat octagonal prism design incorporates several known additive manufacturing benefits, such as secondary structure printed directly into the primary structure and thus reducing the number of parts required to assemble the vehicle. A Pathfinder structure was printed and sine burst tested to 12g, as well as random vibration, to demonstrate the feasibility of an additively manufactured ESPA-class structure to survive flight launch environments. A detailed model correlation effort noted several best practices for finite element models in order to generate acceptable dynamic predictions for this type of architecture. The final correlated model accurately predicts the frequency of major structural modes of the Pathfinder structure within 3% and also provides accurate predictions for high-frequency responses up to 1000 Hz.