The increasingly larger request for access to space, driven by the constant growth of the space economy, leads to the request for new tools capable of performing fast and reliable mission designs. In this context, this master’s thesis is part of a research project of Politecnico di Torino whose purpose is to develop a software tool to support the conceptual design of access-to-space missions with reusable vehicles. In particular, this tool will be able to guide researchers and engineers throughout the very first design phases, allowing the user to carry out quick but reliable analysis of alternative mission concepts. This thesis focuses on the conceptual design of the ascent phase of reusable Single Stage to Orbit (SSTO) launchers.