Development of a Tool for the Design and Verification of Thermal Control Systems of Small Sats

In the context of an ever-growing number of small satellite missions, characterized by low costs, short project lifecycles with fast development time, and a multitude of different mission objectives, various design-aiding tools are needed for every phase of the projects. In particular, in the early phases, where wider margins for modification of the design exist, there is the necessity for comprehensive software that combine the aspect of numerical simulations with automated design generation features and efficient subsystem optimization capabilities. One of the crucial aspects of the design of small satellites is the Thermal Control System, whose importance and relevance is increasing even more in the last years thanks to a growing number of nano and micro satellites operating beyond Low Earth Orbit, in challenging interplanetary environments. This thesis focuses on the improvement and development of a MATLAB® based tool created by the Department of Mechanical and Aerospace Engineering of the Politecnico di Torino, Small Satellites Thermal Tool (S2T2), with special attention to the module of automated optimization of system design. A first state-of-the-art review of the main Multi-Objective Optimization techniques and algorithms is given, with additional details on the "Reference point based archived many objective Simulated Annealing" (RSA) algorithm, which showed promising potential. Then, an improvement of the source code and User Interface of the Design module of S2T2 is presented, starting from the major limitations of the software, and reworking the existing flow, to reach a new, expanded and computationally more efficient Design module. The work is then tested and validated using different case studies: first, a suite of popular benchmark problems for Multi-Objective Optimization is used to compare the performance of the algorithms implemented, and then an application of the tool to the SROC mission is used to test the algorithms and the results in a real-world case study. Finally, the insights and outcomes of the previous studies are applied to the Spei Satelles mission, delivering a new release of S2T2.