Thermal Analysis of 6U CubeSats

Recently, there has been an increase in emphasis on small satellites, however their small size results in small surface areas which often imply thermal and power constraints. For this reason, thermal analysis and design have become of crucial importance for every phases of a space mission project. In particular, since satellites limited power, the active thermal control systems are less employed, so it is important properly choose the passive systems and exploit them to the full. The aim of this study is to present a quite complete description of a thermal analysis, starting from discussing the thermal problem in every aspect, to describing the mathematical methods, which are at basis of the analysis, and finally presenting the computer thermal model. This thesis study has been conducted during a four months internship at Tyvak International SRL, a Terran Orbital Corporation, which provides Nanosatellite and CubeSat space vehicle products and services. During the months of work at Tyvak’s headquarters, the thermal models built have been adopted to carry out a first preliminary thermal analysis, useful for the design and testing phases, of 6U CubeSats developed by Tyvak International SRL for two different European space missions, concerning Earth observation and testing innovative equipment. To solve the analysis, an highly specific software was adopted, Thermal Desktop by Cullimore & Ring Technology, which allows to implement Finite Difference or Finite Element solution to thermal model. A description of the model and how build it has been provided, in particular it has been focused on the Finite Difference Method which permits to achieve an accurate model, adopting the proper amount of nodes for the meshing, which is a compromise between accuracy and execution time. Moreover, the choice concerning the electronic boards modeling was particularly interesting, since they have been modeled as black bodies inside the different components. The results obtained during the internship job gave an experienced confirmation of the thermal model discussed. In fact, after being also validated by other partner companies, they supported the missions feasibility, since every components temperature analysed falls within the operative range, and the design, since thanks to the analyses realised it has been possible to improve the passive thermal control systems, discerning which different superficial treatments was the most effective for the mission.