Closing The Loop In Life Support Systems For Spaceflight And Habitation: Reutilization Of Human Excrement Through Recovery Of Potable Water And Reclamation Of Waste Materials For In-Space Additive Manufacturing
Date of Award
Master of Science (MS)
Pablo de Leon
The National Aeronautics and Space Administration (NASA) solicited a need for a simplified, low-temperature, and robust method for recovery of water from human solid metabolic waste. A solution is investigated, and benchtop testing is performed to prove developmental feasibility utilizing an ionomer-membrane based dehydration approach for potable water recovery. Testing is implemented with synthetic fecal matter, wet wipes, dry wipes, and nitrite gloves to inform system design. The benchtop, closed-system, dehydration testing pulls together a trade space of materials to compare efficacy of designs.
The system aims to recover upwards of 80% of the water content in the human excrement. The most conservative, worst-case scenarios are assumed in testing to ensure system functionality. The setup combines a Universal Waste Management System (UWMS) analog, gas-permeable collection bags, and a counterflow tube-and-shell membrane approach for water evaporation and removal from the human metabolic waste deposits.
Water activity is tracked to evaluate the environment with respect to microbial proliferation. If the water activity level is less than 0.6, drying and stabilization of feces can reduce odor generation and prevent microbial proliferation.
Zimmerman, Brittany, "Closing The Loop In Life Support Systems For Spaceflight And Habitation: Reutilization Of Human Excrement Through Recovery Of Potable Water And Reclamation Of Waste Materials For In-Space Additive Manufacturing" (2021). Theses and Dissertations. 3947.