With a continuously growing number of satellites in orbit, it becomes increasingly important to assess their impacts on the Earth's environment in a standardised manner. While interest in Life Cycle Assessment (LCA) for space missions has gained in strength in the past few years – particularly in Europe – no consensus has yet been reached on a single-score LCA system. In this thesis, a consensus-based space LCA single-score is created through an international survey of experts. The report demonstrates retroactively the single-score’s use in ecodesigning the Delft University of Technology’s Delfi-n3Xt space mission. Moreover, a discussion is held on ways of implementing the single-score into early design phases. Overall, this thesis highlights the importance of an easy-to-understand LCA tool for space systems. It shows the necessity for a tool that is implementable during the design phase of the mission, to incentivise space actors to further consider environmental impacts.