Nanoporous Silica as a Regenerable Sorbent for Potential Integration into NASA's Trace Contamination Control System

Development is underway for the next generation of spacesuits called the Extra-Vehicular Mobility Unit (xEMU). The Exploration Portable Life Support Subsystem (xPLSS) is a vitally important component of the xEMU that is also being developed. The xPLSS is tasked with the maintenance of a breathable atmosphere that is free of noxious volatile molecular species. The purification system that removes contaminants present in the ventilation system is the Trace Contamination Control System (TCC) which is a component in the ventilation loop of the xPLSS. Acid-impregnated activated carbon is the current state of the art for trace contamination control. As this sorbent is non-regenerable consumable, there is a significant impact of logistics on future missions. The primary trace contaminants that must be removed by the sorbent include ammonia, carbon monoxide, formaldehyde, and methyl mercaptan. XploSafe has developed and demonstrated the technical feasibility of a vacuum-regenerable sorbent that could be integrated into the TCC. XploSafe's sorbent media was exposed to 7-day Spacecraft Maximum Allowable Concentrations of the 18 trace contaminants that are present within the xPLSS breathing loop. The trace contaminants were exposed to the sorbent columns individually and in mixtures at relative humidities of 40% and 85% and temperature of 22 C). Adsorption breakthrough volumes and capacities were measured along with regeneration capacity for the sorbent tested with these trace contaminant analytes. Prototype TCC holder design considerations including the required sorbent mass and sorbent holder volume are also discussed.