Carbon emissions reduction of ISRU-enabled mission architectures

This thesis investigates the critical role of In-Situ Resource Utilisation (ISRU) in space exploration, focusing on its impact on mission architecture and carbon emissions. It analyses space resources, propulsion technologies, and ISRU methods, showing how producing oxygen, water, and fuel on the Moon or Mars can reduce launch mass, costs, and dependence on Earth-based supply chains. Overcoming Earth's 9.8 km/s gravity well makes ISRU a potential game changer by sourcing materials beyond it, as seen in processes like molten salt electrolysis of lunar regolith or the MOXIE experiment converting Martian CO₂ into oxygen. The research reviews propulsion systems including chemical, electric, nuclear, and solar sail technologies and evaluates how ISRU-derived fuels can enhance deep space transport. By developing a delta-v roadmap, it compares CO₂ emissions from traditional and ISRU-enabled mission designs, demonstrating ISRU's potential to lower the environmental impact of space travel. Case studies of SpaceX and Blue Origin highlight practical integration – Starship refuelling with ISRU-produced liquid oxygen in lunar orbit and New Glenn's role in a cislunar transport network. Both show that ISRU could drastically reduce reliance on Earth-supplied fuel. Finally, the thesis examines ISRU's influence on mission logistics, vehicle mass, and surface operations. Plant sizing calculations for lunar and Martian installations confirm ISRU's potential as a cornerstone of sustainable space exploration, enhancing mission flexibility and autonomy. Remaining challenges include automation, power generation, and resource characterisation, which are key enablers for its full deployment.