Update on Feasibility of UV LEDs in a Spacecraft Wastewater Tank Application

Abstract

As the National Aeronautics and Space Administration (NASA) expands its scope and begins to venture into long-duration manned space flights, the function and maintenance of spacecraft water systems becomes increasingly critical and difficult to achieve. New mission requirements will limit opportunities for resupply and demand extended periods of dormancy during uncrewed operations. Based on lessons learned from the International Space Station (ISS), one particular challenge of future spacecraft water systems will be maintaining adequate microbial control, especially in water system and component-level elements where effective biocontrol strategies do not currently exist. To ensure the reliability and redundancy in these systems, new technologies will be needed in order to ensure mission success. One application specific microbial control technology under consideration is the use of ultra-violet (UV) light emitting diodes (LEDs). UV-LED technology may reduce the need for consumable resupply, such as filters or biocides, and may minimize crew time associated with the repair and refurbishment of exhausted and/or compromised components and/or systems. Having recently proved preliminary feasibility of commercial off the shelf (COTS) UV-LED devices in a number of spacecraft water system applications, this paper reports on the development of this technology for microbial control in the water processing assembly (WPA) wastewater tank application. The resulting data from this study will be are part of on going efforts to explore the use of UV-LED technology to increase the stability of water systems as deep space missions drive requirements toward more stringent needs for sterility and microbial control.