Development and Performance Test Results of the Starlab Alternative Urine Processor Ground Test Unit

Starlab LLC (Starlab) and Paragon Space Development Corporation (Paragon) are developing the Alternative Urine Processor (AUP), a technology derived from Paragon’s Brine Processor Assembly (BPA). In partnership with NASA’s Commercial Low Earth Orbit (LEO) Destinations Program (CLDP), Starlab will launch its space station later this decade. The AUP is a leading technology to recover water from urine aboard Starlab and other future exploration spacecraft. It utilizes the same membrane distillation bladder technology as BPA but changes key operational parameters and the bladder fill methodology to achieve a higher processing rate that eliminates the need for a separate urine processor upstream of the BPA. A full-scale AUP test unit was designed, built, and tested at Marshall Space Flight Center (MSFC) to evaluate its ability to process urine from 4 crew at a generation rate of 1.8 L of pretreated urine + flush water per crewmember per day. The AUP is a self-contained urine processor which accepts urine that has been pretreated to inhibit microbial activity, prevent the volatilization of contaminants, and evaporates and purifies water into the cabin air or to a Humidity Control System (HCS). The AUP is a 2-bladder system that operates with a semi-continuous fill and dewatering process instead of a batch process like BPA. The AUP was designed, tested and shown to recover greater than 95% of available water from 95th percentile urine pretreated (PTAU95) with the US Alternative (Alt) Pretreatment. This single unit achieves the same water recovery rate as the state-of-the-art ISS Urine Processor Assembly (UPA) + BPA, at a fraction of their combined mass and volume. In addition, testing demonstrated that odor and vented constituents complied with a cycle-average mean Odor Activity Value (OAV) of less than 10, computed using the Single-Compound Odor Thresholds (SCOTs) and 180-day Spacecraft Maximum Allowable Concentrations (SMACs) respectively.