A system of previously undefined environmental life cycle cost elements were developed for use in the propellant selection processes for spacecraft launch propulsion systems, with input from the National Aeronautics and Space Administration (NASA), the Swedish Space Corporation, and stakeholders in industry and academia. These environmental life cycle cost elements were incorporated into a life cycle cost analysis of toxic propellant (hydrazine) versus green (High Performance Green Propellant) through a modified cost benefit analysis. Environmental cost element line items within the life cycle were identified as costs or benefits (cost reductions or avoided costs). A case study was also implemented to further illustrate these findings, resulting in a real-world 66% reduction in Phase E (operational) mission cost for High Performance Green Propellant (HPGP) compared with hydrazine. Based on the analysis, the largest environmental cost drivers were facility operations and maintenance, end of life disposal, and transportation, with the major costs being associated with health and human safety protection.