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

The National Aeronautics and Space Administration (NASA)has a clear need to develop new technology to meet the challenging objectives of long-term space missions included in the Artemis Program. New objectives include sending astronauts to the surface of the Moon and then embarking on missions to Mars. Many of the missions exploring the lunar surface and Martian environment will be longer than current extravehicular activity (EVA) time frames and therefore the development of new, robust, and lightweight life support systems will be required. In these 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 temperature of 205°C. The technology currently planned to replace the Metox in the Exploration Extravehicular Mobility Unit (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 H2Oand CO2 to vacuum prevents the reclamation of these compounds which may be unacceptable in advanced EVA 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 CO2and H2O under EVA conditions and allows for the reclamation of both removed products. The system was challenged with an inlet CO2flow rate representative of a metabolic rate of 2000 Btu / hr and residence time representative of full scale conditions. It maintained the outlet CO2concentration at a constant value of 0.05%, or 0.31 mm Hg, which is significantly lower than the required level of 3.0mm Hg. In addition, the system was able to maintain the outlet humidity content of the process stream at 40% relative humidity (RH)when challenged with inlet humidity ranging from 40%-90% RH.