Design improvement and analysis of quadrilateral mechanism locks for microsatellite docking systems

The rapid growth of the New Space Economy has led to an increased use of mi-crosatellites and nanosatellites, due to their lower costs and faster development. In recent years interactions between spacecrafts in terms of on-orbit servicing, assembly and active debris removal have become appealing fields of interest furthering the expansion of existing space assets and development of novel so-lutions. Amid the growing interest in the subject over the last two decades, the University of Padova has actively participated in the study and development of docking solutions, including DOCKS, the drogue-probe docking system this the-sis focuses on. Specifically, the primary objective of this work is to enhance the hard-docking part of DOCKS by introducing a redesigned quadrilateral mecha-nism with three locks. This mechanism plays a critical role in securing the dock-ing interface, ensuring a stable and reliable connection between the two space-crafts. After providing a comprehensive background on docking solutions in the introduction, highlighting the transformative role and growing importance of small satellites, the thesis objectives are outlined, and the system is character-ized through kinematic and force analysis. The proposed redesign addresses key performance limitations of the existing drogue-probe docking system, par-ticularly in terms of locking capabilities and resource utilization. It features ad-justed dimensions and actuators selection to minimize its impact on the mi-crosatellite's power consumption and weight constraints. To address scenarios where mechanism opening failure may occur, a release mechanism has been developed, providing a contingency measure by enabling the disengagement of the drogue-probe docking interface. The release mechanism's design ensures safe and controlled separation, preventing damage to the spacecraft or pay-loads. The enhancements have been evaluated through simulation, demonstrat-ing significant improvements in docking performance and resource efficiency. Future research directions include improvements in some critical aspects, such as further miniaturization of some components, an overall optimization of the mechanism and testing.