Innovative Method for CO2 and H2O Sequestration and Reclamation in Long Duration Exploration Portable Life Support Systems (xPLSS)

NASA has a clear need to develop new technology to meet the challenging objectives of long-term space missions in advanced environments such as the surface of the Moon and Mars. In these extravehicular activity (EVA) applications, the control as well as conservation of CO2 and H2O is critical. Historically, the Metox has been used to remove CO2 from the Extravehicular Mobility Unit (EMU) during EVA’s. However, this unit utilizes a solid silver oxide sorbent which requires a high mass and volume allocation and requires regeneration in between missions at a high temperature. The technology currently planned to replace the Metox in the xEMU is the Rapid Cycle Amine (RCA). This device utilizes a regenerable, pressure swing adsorption system which adsorbs CO2 and H2O from the suit and then desorbs said compounds through exposure to space vacuum. While this device does not have a finite capacity like the Metox, the desorption of the H2O and CO2 to vacuum prevents the reclamation of these compounds which may be unacceptable in advanced environments where resources are limited. In this SBIR Phase I project, Reaction Systems developed a novel system which utilizes a high-capacity liquid sorbent and a hollow fiber module to control CO2 and H2O under EVA conditions while still allowing for the reclamation of both compounds. The system was challenged with an inlet CO2 flow rate representative of a metabolic rate of 2000 Btu / hr at a residence time consistent with full scale conditions. It maintained the outlet CO2 concentration at a constant value of 0.05%, or 0.31 mm Hg, which is significantly lower than the required level of 3.0 mm Hg. In addition, the system was able to maintain the outlet humidity content of the process stream at 40% RH when challenged with an inlet humidity ranging from 40%-90% RH.