Dynamic Response of CubeSat Structures Under Launch Loads: Effects of Internal Mass Distribution

During launch, CubeSats are subjected to severe loads, and the internal mass distribution within their structures can significantly affect their dynamic response and overall structural behavior. An investigation of the structural and dynamic behavior of a CubeSat in representative launch environments, with particular emphasis on internal mass distribution, is crucial to the design and development of a CubeSat structure. A finite element model of the CubeSat is developed using a simplified but realistic structural representation, including deployer-representative boundary conditions and internal subsystem masses arranged in several alternative configurations. Quasi-static analysis is performed first using equivalent inertial load cases to assess stress distribution, displacement, and structural load transfer. Then modal analysis was performed to identify the fundamental natural frequencies and dominant mode shapes for each configuration. Finally, a random vibration analysis is performed with power spectral density inputs from a selected launcher to study the acceleration response. By comparing multiple internal mass layouts, the study examines how mass placement alters modal characteristics, modifies load paths, and affects the overall structural behavior of the CubeSat during launch. The results are used to identify trends relevant to the early-stage CubeSat design, particularly with respect to structural robustness and the protection of sensitive subsystems. The proposed approach provides a practical framework for structural assessment and offers design-oriented insight to improve the launch survivability of small satellite platforms.