Evaluating End-of-Life Scenarios for Satellites Using Life Cycle Assessment

Kurzfassung

As the number of satellites in orbit continues to grow, the end-of-life (EoL) phase of spacecraft presents critical challenges for orbital sustainability and environmental responsibility. Current EoL strategies, such as natural reentry, controlled reentry, and graveyard orbits, aim to mitigate space debris but have varying environmental implications that remain insufficiently explored. During reentry, up to 90% of satellites are vaporized [11], releasing metals, resins, and other toxic substances into the atmosphere [7], contributing to acidification, climate change, and particulate matter formation. Graveyard orbits, while reducing short-term collision risks, exacerbate long-term orbital congestion, and fragmentation potential. This study addresses the current methodological gap in environmental assessments of satellite EoL scenarios by introducing a combined Life Cycle Assessment (LCA) framework that integrates the Environmental Footprint 3.1 method with a dedicated Space Debris Indicator (SDI), enabling the evaluation of both terrestrial and orbital impacts. This combined framework evaluates environmental trade-offs across terrestrial, atmospheric, and orbital environments, providing an integrated view of satellite EoL impacts. Using a CubeSat as a case study, results indicate that controlled reentry has a higher environmental burden than natural reentry across multiple impact categories, not only due to fuel combustion but also because of a higher percentage of material ablation [13]. While natural reentry generates relatively lower atmospheric emissions, it results in a larger mass of surviving fragments. However, these fragments contribute minimally to the overall environmental impact compared to the emissions from atmospheric ablation. In contrast, graveyard orbits eliminate atmospheric emissions entirely but represent the most significant challenge for long-term orbital sustainability, with the highest Space Debris Index, underscoring their lasting impact on orbital congestion and fragmentation risks. These findings underscore the need for EoL strategies that balance short-term environmental impacts with long-term orbital sustainability. Exploring circular economy principles and innovative materials, such as wood-based structures to mitigate aluminum oxide pollution, presents promising pathways. Additionally, enhancing on-orbit operations through maintenance, repair, and upgrading would extend satellite lifespans, possibly reduce new launches and support orbital sustainability goals.