Towards a circular space economy: Knowledge and classification of end-of-life equipment on the moon

• Proposed a novel classification framework for equipment available on the Moon, integrating their composition, mass, and locally available resources. • Explored the material composition and potential applications from end-of-life lunar equipment to support sustainable lunar operations. • Provided the limitations of terrestrial recycling processes and assessed their applicability for lunar recycling operation. • Analysed key challenges for recycling under lunar environmental conditions and handling heterogeneous materials. • Proposed strategic prioritisation of materials for recycling to emphasise their economic importance and future design considerations for developing robust lunar recycling systems. The volume of hardware accumulating on the lunar surface is increasing at an unprecedented rate due to increased interest from both governments and the private sector. For this reason, developing lunar hardware recycling systems presents several opportunities, including waste reduction and the minimization of resupply missions from Earth. In this context, this study reviews the composition and potential applications of lunar hardware to support sustainable long-duration lunar missions. Here, we propose a novel classification framework for recycling feedstock based on its composition, mass, and locally available lunar resources. This framework enables a systematic prioritisation of end-of-life equipment according to recycling potential and economic importance under lunar conditions. Furthermore, we assess the limitations of terrestrial recycling processes for lunar operations and outline the challenges associated with the handling heterogeneous feedstocks. Finally, future considerations for developing robust lunar recycling systems are discussed and supported by practical examples to establish a sustainable lunar circular economy.