The goal of this project was to evaluate the state-of-the-art of European and US solid propulsion stages and to create an Excel-based design model/workbook for solid propulsion stages. The tool is intended to be used, amongst others, by the ESA CDF for either selecting existing solid rocket motors from a suitably populated database or creating preliminary designs for new solid rocket motors. Having a workbook to model stages based on solid propulsion will help assessment studies to perform trade-offs taking solid propulsion stages into account.