Preliminary System Budgeting of a Robotic Free-Flyer System for a Space Station

The MELISSAI project aims to develop the first Italian free-flyer platform, for orbital robotics applications designed to validate algorithms, devices and operational concepts in the field of Guidance, Navigation and Control (GN&C). These key functions form the basis for In-Space Servicing, Assembly, and Manufacturing (ISAM). ISAM represents the future of low Earth orbit utilization, spanning from satellite servicing and refueling, to in-orbit assembly of complex structures, to manufacturing of goods in space for both orbital and terrestrial use. The platform is intended to evolve into a flight-ready system capable of operating on the International Space Station (ISS), Lunar Gateway and future commercial human space stations. The project will establish Italy and Europe as a provider of free-flyer robotic services reducing reliance on foreign programs. The system architecture consists of two units, a catcher equipped with a robotic arm and a target equipped with a handle for grasping, and integrates an attitude control system, a set of cameras for visual based navigation, an androgynous docking interface, a common active interface (CAI) device and a compressed-air propulsion system. The objective of this Master’s Thesis is to develop the preliminary system budgets of the MELISSAI payload, fundamental in early design stages to provide a framework for feasibility and trade-offs, ensuring subsystem consistency, lowering integration risks and avoiding redesigns. The work encompasses mission contextualization, system characterization, and the formulation of initial budgets with their associated requirements in line with ECSS standards. The thesis is structured as follows: Chapter 1 introduces the mission context, the MELISSAI platform and the concept of system budgets; Chapter 2 develops the mass budget through subsystems estimation methods using historical data and analogies; Chapter 3 details the power budget, including subsystems consumption, operational modes and duty cycle generation; Chapter 4 addresses the data budget, focusing on communication, handling and storage needs; Chapter 5 defines the volume budget, examining subsystem accommodation within design constraints; Chapter 6 formalizes a set of system requirements derived from the budgeting process; Chapter 7 provides conclusions and outlines future developments of this thesis.