ARCADE small-scale docking mechanism for micro-satellites

The development of on-orbit autonomous rendezvous and docking (ARD) capabilities represents a key point for a number of appealing mission scenarios that include activities of on-orbit servicing, automated assembly of modular structures and active debris removal. As of today, especially in the field of micro-satellites ARD, many fundamental technologies are still missing or require further developments and micro-gravity testing.In this framework, the University of Padova, Centre of Studies and Activities for Space (CISAS), developed the Autonomous Rendezvous Control and Docking Experiment (ARCADE), a technology demonstrator intended to fly aboard a BEXUS stratospheric balloon. The goal was to design, build and test, in critical environment conditions, a proximity relative navigation system, a custom-made reaction wheel and a small-size docking mechanism.The ARCADE docking mechanism was designed against a comprehensive set of requirements and it can be classified as small-scale, central, gender mating and unpressurized. The large use of commercial components makes it low-cost and simple to be manufactured. Last, it features a good tolerance to off-nominal docking conditions and a by-design soft docking capability.The final design was extensively verified to be compliant with its requirements by means of numerical simulations and physical testing. In detail, the dynamic behaviour of the mechanism in both nominal and off-nominal conditions was assessed with the multibody dynamics analysis software MD ADAMS 2010 and functional tests were carried out within the fully integrated ARCADE experiment to ensure the docking system efficacy and to highlight possible issues. The most relevant results of the study will be presented and discussed in conclusion to this paper.