Capillary fluidic solutions to the challenges of water recycling aboard spacecraft are gaining ground. Such solutions exploit surface tension, wetting, and system geometry to passively position fluids in desired locations for reliable collection, separation, and transport. Because such aqueous streams can be highly contaminated with particulates and gases, passive no-moving-parts solutions are attractive due to their simplicity and increased reliability. In this research, we demonstrate the marked improvements in passive system performance that can be achieved with the judicious use of superhydrophobic substrates and surfaces, which have not been aptly exploited aboard spacecraft to date. We first highlight the many current life support systems that can benefit from such non-wetting surfaces. We then identify the variety of monolithic materials and coatings suitable for spacecraft deployment with holistic considerations for the complete life support system. As our Phase I deliverable, we down-select, construct, and demonstrate a high-performance passive urine collection and transport device for advanced spacecraft life support that is largely contamination-free, reducing or eliminating the need for replacement spares and saving on costs, mass, volume, and crew time. Further, a low-cost fast-to-flight technology demonstration aboard ISS is proposed as part of our broader Phase II effort.
Sample applications include urine collection and distillation elements, bubble separations, plant watering systems, condensing heat exchangers, and others. Single-use disposable devices as well as permanent life support equipment can benefit in microgravity environments aboard ISS and Orion as well as Lunar and Martian systems.
Commercial aerospace providers will benefit from enhanced performance of certain space hardware similar to NASA. Terrestrial applications may also benefit via enhanced microscale fluids management, and at the macroscale, self-cleaning and anti-fouling properties.