Ultra-Pure, High Endurance Liquid Bladder with Volume Sensor for Space Applications



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51st International Conference on Environmental Systems


The NASA Portable Life Support System (PLSS) for the Exploration Extravehicular Mobility Unit (xEMU) incorporates a Feedwater Supply Assembly (FSA) to store consumable cooling water. The FSA accepts pure water prior to each Extra-Vehicular Activity (EVA), then supplies this water to a membrane evaporator at ambient suit pressure during the eight hour EVA. The FSA must function reliably for hundreds of EVAs over 15 years of service without introducing contamination that may accumulate and foul the membrane. We present a unique design that combines the benefits of a flexible fluoropolymer bladder with the strength and convenience of a rigid tank, providing an ultra-pure, ambient-pressure reservoir with fill-drain cycle life exceeding 3000, internal pressure tolerance exceeding 100 psi, high volumetric efficiency, near-zero dead volume, optical transparency for visual inspection, simplified mounting, and very low mass. We also incorporate a novel volume sensor suitable for both microgravity and arbitrarily accelerated environments and capable of real-time monitoring with accuracy on the order of 2.5% full scale. Analytical predictions are supported by experimental test data from a mature subscale prototype.


Marc Ramsey, RAPA Technologies, US
Cinda Chullen, NASA JSC, US
Raymundo Moreno, Jacobs, US
ICES402: Extravehicular Activity: PLSS Systems
The 51st International Conference on Environmental Systems was held in Saint Paul, Minnesota, US, on 10 July 2022 through 14 July 2022.


PLSS, Portable Life Support System, FSA, Feedwater Supply Assembly, xEMU, Bladder, Fluid, Liquid, Reservoir, Evaporative, Cooling, Water, Pure