Thermal Modelling and Analysis of a 12U CubeSat for Earth Observation

In recent years, interest in nanosatellites has increased. Progress in nanotechnology has enabled the birth and increasing use of CubeSats, satellites that are considerably smaller than conventional spacecraft, allowing for faster mission development times and lower costs. For these satellites, the Thermal Control System (TCS), which allows, despite the rigidity of the space environment, to ensure the proper functioning of the various subsystems, is subject to new problems. In fact, given the small size of the CubeSats, the power generated inside the satellite is limited, and in the choice of thermal control systems, passive systems are preferred since they do not require a power source. Therefore, to carry out an initial sizing of the TCS, it is crucial to estimate the satellite’s temperature values during the mission’s various phases. In a first approximate analysis, this thesis work aims to evaluate the temperature trends of the subsystems inside a CubeSat 12U on which an optical camera for Earth observation is installed as a payload. The work was conducted at NPC Spacemind, a company specialising in researching and developing products for space applications. With the help of the Thermal Desktop software, a model was created to simulate thermal behaviour as a function of different operating modes, using the Finite Difference Method. The implemented analyses simulate the most and most minor power-consuming operating modes in order to evaluate extreme cases, which are dimensioning for choosing the appropriate thermal control system for the satellite. The results make it possible to verify whether the subsystems installed inside the CubeSat are within the operating temperature range. The analysis represents a starting point for the subsequent design phases, in which more detailed thermal models will be considered, and the results will be validated through experimental analyses.