Assessment of the impact of miniaturized electric propulsion systems on small satellites technology

The present thesis was born as part of a joint project between the CubeSat Team of Politecnico di Torino and the European Space Agency (ESA). This project, named ESA-Prop has the goal to design a platform devoted to the test and qualification of miniaturized electrical propulsion systems for CubeSats. The idea is to increase the devices Technology Readiness Level (TRL) and to study the mutual interaction occurring between the propulsion system and the host platform. The ultimate goal of the project is to provide a one-stop test facility for the qualification of CubeSats featuring propulsion systems on board. This thesis covers the last part of the phase one of the project, with the feasibility concept and the integration and test of the prototype, and the early stages of phase two, with the definition of tests and the upgrade of the prototype to host the ePS and collect relevant data. Its focus is on the assessment of the impact and mutual interaction of an ePS on a CubeSat platform, particularly on the thermal aspects. The first part of this thesis focuses on an overview of the State-of-the-Art of miniaturized electric propulsion. most prominent solutions have been identified and their capabilities and limitation analysed. They where cross checked with a preliminary analysis of different mission scenarios, creating a matrix summarizing ePS capability to fulfil different roles. An overview of the different aspects an ePS will impact over the CubeSat is then analysed, and then measurements of interest are identified. In order to define qualification tests and test platform design, sensors to be used are identified and discussed, with a focus on those measurements that have been defined as priority during a meeting with ESA customers. The thesis then covers the integration and testing phases of the prototype both in Turin and at the Electric Propulsion Laboratory at ESA/ESTEC. It provides a status of the project at prototype phase, that is the starting point for the upgraded version that will implement the sensors to acquire the measurements discussed in the previous chapter. A focus is then put on the assessment of the thermal aspects of the interaction between the ePS and the platform. The operational environment and the test environment are defined and discrepancies between the two identified. It is then described the thermal model of the platform designed with thermal desktop to define the optimal points for temperature sensors. The model provides a firs approximation of the heat loads and temperature map of the test platform, enabling test designers to position thermistors accordingly. Thermal model outputs are then verified and corrected empirically thanks to an ePS thermal load emulator, composed by an aluminium structure with dissipating resistors simulating the dissipated power of the ePS. Next phases of the project will see the completion of the new avionics design, with more acquisition lines, allowing other sensors to be tested. At the end of test definition and platform upgrade the new test platform will be integrated with an ePS and actual tests will be conducted in a vacuum chamber.