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.