Within this context, aluminium alloys combine high specific strength with good environmental stability in space and are therefore widely used for primary and secondary structures.
A promising response is to tailor spacecraft for demisability and low environmental impact at the end of life.
Beyond wood, other circular material classes merit parallel consideration, including natural-fibre-reinforced composites, thermosets and thermoplastics derived from renewable or waste feedstocks, including biodegradable polymers such as polylactic acid (PLA).
Life Cycle Assessment (LCA), following the ISO 14040/44 framework and adapted by ESA for space systems, provides an established method for quantifying environmental impacts across the mission life cycle.
Recent work further extends conventional LCA by combining the Environmental Footprint 3.1 method with a dedicated Space Debris Indicator, allowing end-of-life scenarios, including natural re-entry, controlled re-entry and graveyard disposal, to be compared across terrestrial, atmospheric and orbital impact domains10.
Material standards and related ECSS requirements, such as ECSS-U-AS-10C Rev.2 (adoption of ISO 24113:2023), address space-debris mitigation, re-entry casualty risk and design-for-demise considerations, while dedicated ECSS material standards govern thermal-vacuum outgassing (ECSS-Q-ST-70-02C), resistance to particle and UV radiation (ECSS-Q-ST-70-06C), and resistance to atomic oxygen for materials exposed on external surfaces in LEO (ECSS-Q-ST-70C Rev.2). Within this context, aluminium alloys combine high specific strength with good environmental stability in space and are therefore widely used for primary and secondary structures. However, re‑entry‑derived metal‑oxide emissions and the energy and resource‑intensive production of aluminium motivate the exploration of alternative approaches that reduce environmental impacts across the life cycle.
A promising response is to tailor spacecraft for demisability and low environmental impact at the end of life. Strategies include the use of low‑melting or fragmenting alloys in non‑critical elements, polymeric or composite structures designed to ablate completely and foamed or hollow configurations that promote breakup and oxidation8. Such choices can be applied selectively to secondary structures, bracketry, instrument housings or sacrificial elements, complementing more conservative materials in propulsion, pressure vessels and other critical subsystems. Within this broader landscape of demisable, low‑impact solutions, bio-based materials such as wood offer a distinctive combination of renewable resource base, with relatively low carbon footprint in production and intrinsically benign re‑entry behaviour, making them a particularly attractive option for sustainable, demisable spacecraft components. Beyond wood, other circular material classes merit parallel consideration, including natural-fibre-reinforced composites, thermosets and thermoplastics derived from renewable or waste feedstocks, including biodegradable polymers such as polylactic acid (PLA). High-performance thermoplastics such as PEEK may further support design-for-demise and have already been shown to improve the demisability of critical fasteners relative to steel or titanium baselines9.
Quantitatively grounding the choice among these candidates requires a full life-cycle perspective. Life Cycle Assessment (LCA), following the ISO 14040/44 framework and adapted by ESA for space systems, provides an established method for quantifying environmental impacts across the mission life cycle. Recent work further extends conventional LCA by combining the Environmental Footprint 3.1 method with a dedicated Space Debris Indicator, allowing end-of-life scenarios, including natural re-entry, controlled re-entry and graveyard disposal, to be compared across terrestrial, atmospheric and orbital impact domains10.
