For long-duration space missions, the mass of the initial stock of supplies (e.g., food, water, air, spare parts) must be limited and the number of items that require resupply during the mission must be minimized. Given these constraints, regenerative environmental control and life support systems (ECLSS) are a necessity. Membrane processes are ideal for regenerable ECLSS because membrane processes 1) operate reliably for long periods, 2) are simple to repair and maintain, and 3) do not require consumable or expendable materials.
In this paper, the uses of membranes in a regenerable ECLSS are reviewed. System designs and experimental data are presented on the use of membranes for the purification and recycling of water (e.g., the treatment of hygiene water, urine, humidity condensate and phase-change distillate) and for the treatment and purification of air (e.g., removal of water vapor and carbon dioxide).