Autonomous docking manoeuvre Testing in the framework of the ERMES experiment

The advent of the recent ”New Space Economy” allowed access to low-Earth orbits to a rising number of commercial enterprises, non-profit groups, and educational institutions. As a consequence, the global small satellite market has grown substantially, since they have proven to be a suitable low-cost alternative for several space missions and technological demonstrations. In this context, proximity operation systems for autonomous small satellites are continuously under investigation, due to their effectiveness for many applications. Experimental Rendezvous in Microgravity Environment Study (ERMES) is a student project, which aimed at testing an autonomous docking manoeuvre between two free-flying CubeSats mock-ups in a reduced gravity environment. The manoeuvre is characterized by an active Chaser and cooperative Target approach. In particular, the Chaser is equipped with a cold gas propulsive system based on expendable CO2 cartridges for 3-dimensional manoeuvring, whereas the Target has a set of reaction wheels for attitude control. The magnetic post-manoeuvre connection is achieved thanks to a dedicated miniaturized docking interface. Moreover, the reduced gravity conditions have been achieved by participating in the European Space Agency (ESA) 79th Parabolic Flight Campaign thanks to the selection in the ESA Fly Your Thesis! Programme 2022 (FYT). This article depicts an overview of the ERMES experiment, discussing its core objective and key design solutions, up to analyzing the results of the tests carried out during the aforementioned Parabolic Flight Campaign. Relevant focus is dedicated to the investigation of the functionality and effectiveness of the Guidance Navigation and Control (GNC) system of the Chaser.