Duration: 18 months
Bio-regenerative life support systems (BLSS) use higher plants for providing oxygen, clean water, and food. Closed-loop plant cultivation systems offer sustained operation with fewer resupplies from Earth. However, they are prone to nutrient imbalance over time due to recirculation of the nutrient solution and nutrient consumption rates of the plants that do not match nutrient feed rates and composition, especially when using mineralized waste as a nutrient source. Therefore, real-time nutrient concentration monitoring and control is needed and can best be achieved with soilless closed-loop systems. Soilless systems in fractional gravity require a gas/liquid separation between the root and shoot zone of the cultivation chamber to prevent water from adhering to the shoot. Plant-cultivation technologies for the ISS (Advanced Plant Habitat, NASA PONDS, Veggie, PFPU) are typically made for short-term cultivation, use capillary growth substrates to control the gas/liquid interface, and lack capabilities for nutrient solution recirculation and precise process control. Furthermore, their substrates are typically not reusable and require crew time to manually seal the root module to limit evaporation. Our preliminary technology, a newly developed membrane, makes self-sealing gas/liquid separation around the plant possible for the first time. This represents a critical step towards precise nutrient concentration control in closed-loop soilless systems in fractional gravity and the future use of mineralized waste enhancing sustained operation even more.
We intend to design, build and test a root module, based on the membrane, for a closed-loop soilless system suitable for operation in fractional gravity. This includes further characterisation of the membrane, exploring concepts for oxygenation of the water and testing with plants. The project goal is a ground-demonstration of an integrated hardware that allows for plant seed germination and plant growth and development.
