Closed-Loop Hospitality as a Sustainability Assessment Framework for Space-Analogue Habitats

Closed-loop habitats in space-analogue and other extreme environments must sustain life and performance within tightly bounded constraints on water, energy, food, air revitalisation, waste processing, space, and crew time. Existing assessments emphasise engineering reliability, resource throughput, and human factors, but less often address everyday practices—meals, hygiene, privacy, social rituals, sensory comfort, and care work—as variables relevant to sustainability. This conceptual paper develops closed-loop hospitality as an integrated sustainability assessment framework for analysing how such practices mediate between resource constraints and environmental, social, and operational outcomes. Drawing on sustainability assessment, circular resource use, resilience, socio-technical systems, habitability, and hospitality theory, the framework links constraint variables—including resupply interval, closure ratio, bottlenecks, redundancy, volumetric capacity, crew time scarcity, intercultural crew composition, and health-support capacity—to hospitality design choices and measurable indicators. It identifies outcomes such as resource intensity, recycling and waste burden, system reliability, labour distribution, equity and legitimacy of access, psychosocial wellbeing, compliance, and adaptive resilience. The paper supports threshold setting, scorecards, and protocol design in analogue habitats, arguing that sustainable habitation requires balancing resource stewardship with minimum viable hospitality: preserving dignity, care, privacy, cohesion, and operational continuity within closed-loop limits.