Closing the Water Loop for Exploration: 2022 Status of the Brine Processor Assembly

Paragon Space Development Corporation developed a Brine Processor Assembly (BPA) for demonstration on the International Space Station (ISS). BPA recovers water from urine brine produced by the ISS Urine Processor Assembly (UPA) via a patented process and ground testing has demonstrated water recovery rates greater than 90% from the previously concentrated urine brine. BPA utilizes the forced convection of spacecraft cabin air coupled with a membrane distillation process to recover purified water from 22.5 liters of brine within a 26 day cycle. By increasing overall water recovery on ISS to greater than 98%, BPA demonstrates a critical capability needed to close the brine processing technology gap identified in NASA's Water Recovery Technology Roadmap. This paper discusses operational progress since launch to the ISS in February 2021.

After installation, checkout, and activation on the ISS, BPA operations were successfully initiated in April 2021. Despite successful nominal operation, crew members expressed discomfort due to malodor from effluent BPA air. After the initial dewatering cycle was completed, it was determined that BPA would need to mitigate odor before on-orbit operations resumed. To address these concerns, an outlet filter system was developed, and an extensive characterization study was conducted to test the efficacy of the filter in reducing odor. This study included analysis of gas, odor, and condensate samples of filtered and unfiltered effluent air during a brine dewatering cycle with an identical BPA ground unit. The filter assembly demonstrated > 85% first pass reduction in odor without detrimental effects to BPA operations. As a result, a similar assembly was launched to the ISS, installed, and BPA operations were resumed in October 2021. This technology achieves an essential capability to enable human exploration of deeper space, and this experiment was an opportunity to identify the importance of human factors in life support spaceflight hardware.