This project has received phase 1 NASA NIAC funding in 2012.
The history of life support systems in space shows that mechanical life support systems have high duty cycles and consequent failure rates that make them problematic for long duration missions. Water Walls offers the potential for a largely passive system based on forward osmosis processes that will be much more reliable for long duration human exploration missions. Water Walls can also provide nutrient production and radiation shielding
Water Walls (WW) presents a new approach to long duration life support. Instead of providing one or two heavy, excessively complex and, sensitive, expensive, and failure-prone pieces of mechanical equipment, the WW approach provides a large number of simple units based on forward osmosis (FO) to handle the same functions as conventional systems – and more.
Instead of continuously active mechanical systems, WW is mostly passive, with only valves and small pumps as active elements – no compressors, evaporators, sublimators, distillers, adsorbers, or desorbers. Instead of the failureprone mechanical Environmental Control and Life Support System (ECLSS) equipment that must operate continuously, WW modules are designed to have their capacity consumed gradually throughout the mission. As one unit is used up, the next in line takes over. In the case of the blackwater/solids cells, they leave a residue of dry biomass and CaCO3 that can continue to provide radiation shielding.
An interplanetary spacecraft would launch with its WW modules dry, then in Low Earth Orbit (LEO) or at an Earth-Moon Lagrange Point, they would be primed with water to “fuel” the life support. WW offers the promise of an inexpensive, modular, simple, low maintenance, highly reliable, and massively redundant system to outfit human interplanetary spacecraft, lunar, and Mars bases. Between interplanetary missions or for scheduled maintenance at a lunar/planetary base, crewmembers refurbish the Water Walls systems simply by replacing the disposable FO bags or membranes.
Michael Flynn with the FO (Forward Osmosis) urine and gray-water processing array for the NASA Ames Sustainability Center, set up for testing in the Bioengineering Branch life support lab.
Functional Flow Diagram for Water Walls System Architecture