Brine Processor Assembly 2023-24: Operational Successes and Challenges on the International Space Station

The Brine Processor Assembly (BPA), developed by Paragon Space Development Corporation as a one-year technology demonstration, has now been in operation onboard the International Space Station (ISS) for three years. BPA recovers available water from urine-brine produced by the ISS Urine Processor Assembly (UPA) via forced convection of cabin air coupled with a patented membrane distillation process. A dual-layer ionomer and microporous membrane-based bladder retains the liquid brine while water vapor pervaporates into the cabin, for collection as humidity condensate. This paper will discuss updated performance results as well as the practical operational challenges of maintaining hardware on the ISS.

In August 2023, BPA operations were automatically halted when the Brine Leak Alarm annunciated. Crew opened the BPA to confirm that there was no actual leakage of brine, upon which it was discovered that corrosion had developed on the Brine Leak Sensor. Paragon has been working with NASA to extend the life of the sensor and safely operate BPA, as well as to launch the spare replacement component. As of May 2024, 41 full operational runs have been completed spanning 612 days of active operations, recovering an estimated 741 kg (L) of water from urine-brine. This represents a cost savings of over $80 million from the mass of water that has not needed to be launched to or discarded on ISS, minus the cost of consumables (bladders and odor filters). The BPA currently has an impressive 6x water-to-up mass recovery ratio, meaning BPA has recovered 6x as much water as the mass of the BPA hardware itself and all consumables (bladders, spares, and odor filters). This has helped NASA to claim 98% water recovery on ISS, achieving an essential capability to enable human exploration of deeper space.