In spite of significant reduction of cost associated with launching a spacecraft, launching deep space exploratory missions are yet to be accessible to most universities and researchers. A solution to testing scientific hypotheses and verifying technologies for space is the use of environmental chambers, also know as space simulators, - vacuum chambers, which replicate the space environment. The scope of this thesis project is to develop a thermal control system for a space simulator, which would replicate the environment on Mars, and allow for controlled carbon dioxide ice deposition experiments. The first part of the thesis looks at the climate on Mars, and the process behind the carbon dioxide ice cycle, gives a description of the systems in a space simulator. Then the requirements of a thermal system for the space simulator are stated. The second part of the thesis gives a brief overview of the previous solution attempts at the laboratory in Luleå University of Technology, and the manufacturing technologies required to make them. Based on that, a design justification is given. The thermal control system design section gives an overall design description, with detailed report on the iterative design of the sample holders, and thermal simulations results. Additive manufacturing is analyzed, as means of producing solid designs with the necessary performance targets. The overall cost of the designed thermal control system is calculated, and further work directions are proposed. The appendices include the literature used, the technical drawings for manufacturing and assembly of the thermal system, detailed budget calculations, and additional data from the thermal analysis.