Photocatalytic Water Recycling for Short Duration Missions

This proposal outlines the development of an innovative Water Recovery and Management (WRM) system, designed for efficient operation in the confined spaces of early-phase lunar and Mars habitats, landers, and pressurized rovers. The current WRM system used on the International Space Station (ISS) has considerable size and complexity, primarily due to the Catalytic Reactor in the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). Our proposed system introduces a novel photocatalytic oxidation (PCO) reactor system, replacing the traditional 2-phase Catalytic Reactor. This reactor utilizes TiO2 as a photocatalyst under UV radiation, enabling oxidation of organic compounds in single-phase liquid water. The ambient operational conditions of the PCO reactor significantly simplify the contaminant oxidation process, reducing the need for heaters, pressure regulators, and other complex components associated with the current system. A novel aspect of our approach is the integration of the PCO reactor with an ion-exchange (IX) bed in a recirculation loop, dramatically enhancing energy efficiency and reducing IX resin requirements. Addressing the challenges of system dormancy, particularly for lunar missions, we propose a strategy for system recovery and recirculation to ensure water quality post-dormancy. The PCO reactor's design is robust against extended periods of inactivity, while the impact on sorption media will be thoroughly tested during the Phase I and II programs. Our approach includes a novel urine pretreatment method, utilizing non-toxic chemicals for biological control, significantly reducing Equivalent System Mass (ESM) and enhancing safety. The proposed PCO/IX system is compact, energy-efficient, and low-maintenance, meeting NASA's stringent water quality specifications. It represents a significant advancement in space-based water processing technology, offering a scalable and reliable solution for future space missions and planetary bases.