A cellulose based biodegradable humidity sensor with embedded salts for crop monitoring and nutrient supply in space greenhouses

Space crews require fresh and nutritious food during extended missions to support both their physiological health and psychological well-being. The most effective solution to this challenge is the implementation of smart greenhouses, designed to operate under specific constraints such as microgravity, artificial lighting, limited storage, resource availability and waste management. To ensure optimal plant growth and prevent damage or crop loss, a robust monitoring system is essential for maintaining the stability and efficiency of these controlled environments. In this regard, sustainable and recyclable tools emerge as a key technology for maintaining system operation such as plant parameter monitoring. In this work we present the fabrication and characterization of a biodegradable humidity sensor based on cellulose embedded with nutrients as a smart concept for an isolated environment as a space greenhouse, where the sensor can be useful even after its lifecycle to offer vital nutrients for the plants optimizing resource utilization and maintaining utility even at the end of their lifecycle.