Integrating Green Propulsive Technologies in Orbital Stages: A Holistic Framework for Mission-Specific Propulsion System Design

The space sector is experiencing rapid and unprecedented growth, marked by an increasing number of payloads launched annually and the emergence of a new market for in-space operations. This evolution had two outcomes: first, a growing market demand for Orbital Transfer Vehicles (OTVs) to address last-mile delivery, in-orbit servicing, active debris removal, and related services; second, a pressing need to assess and mitigate the environmental impact of space activities to ensure their long-term sustainability. This thesis explores the synergy between these two aspects by investigating the integration of green propulsion technologies in OTVs. It introduces a holistic design framework for evaluating and matching future mission concepts, using OTVs as reference system, with their most suitable propulsive solution. The framework considers propulsive performance, environmental impact, cost-efficiency, and system reliability as figures of merit. Developed at the European Space Agency, the environmental impact part of the tool computes the full lifecycle impact of propulsion systems (architecture and propellant), sized to specific mission scenarios. This framework supports early-phase feasibility studies by enabling fast, informed trade-offs between propulsion options and represents a step toward the systematic inclusion of environmental impact as discipline in future space system design.