Vacuum Regenerable Sorbents For CO2 and Humidity Control within the xEMU

In this Phase II SBIR, XploSafe will build on its Phase I work to advance the development and evaluation of sorbents identified during the Phase I. Phase I results demonstrated the feasibility of sorbent candidates as viable replacement for the current carbon dioxide and humidity control solution. The developed materials exhibit significant advantages including higher CO2 capacity and easier regeneration under vacuum. For Phase II, XploSafe will further investigate physical properties as it is related to specific NASA requirements, expand experimental measurements of the capacity and kinetics for the sorption of carbon dioxide and humidity and vacuum regeneration, and develop and verify sorbent performance integration into the xEMU RCA unit. The researchers will focus on developing sorbents with long operational life and reduced or ideally eliminated outgassing of undesired contaminates such as ammonia. A targeted goal will be to use regeneration and potentially a larger CO2 capacity per gram to reduce the required sorbent mass, with respect to SA9T, while also maintaining the CO2 and humidity control under operating conditions. A fully regenerable sorbent with no irreversible binding site and little outgassing, could also reduce both the RCA and TCC total mass by allowing smaller units with less sorbent mass. In Phase II, XploSafe will construct several testing apparatuses to simulate conditions that match the requirements of the xEMU in relation to the RCA unit. The testing apparatuses will enable evaluation of the sorbent media prior to being provided to NASA for possible on-site evaluations. Samples of the developed sorbent prototypes will be provided for formal review by NASA starting after month 12 followed by updated sorbent prototypes that will be available for periodic reviews, and the final sorbent material will be delivered at the end of the project. NASA is poised to make the next step out into the solar system with Human Exploration of the Moon, Mars, and beyond. Highly reliable, efficient, capable and reliable space suits are one of the keys to the success of this effort. The development is underway for the next generation of spacesuit called the Extra-Vehicular Mobility Unit (xEMU The safe operation of the xEMU requires control of CO2 and humidity levels. Rapid Cycle Amine (RCA) technology is currently the basis for meeting this requirement in the xEMU. This technology provides regenerative CO2 and humidity removal via a pressure swing adsorption system with an amine based sorbent that desorbs the gases upon exposure to vacuum. The development of new sorbent for RCA with superior stability, higher capacities for water and carbon dioxide, and faster kinetics for uptake and release will facilitate reduction in power draw, volume envelope, and mass while maintaining the current CO2 and humidity removal capacity while minimizing or eliminating requirements for astronaut maintenance. Success in the completion of Phase I has provided clear direction towards the development and operational evaluation of sorbent material prototypes during Phase II. Phase II objectives will focus on optimizing the sorbents and performing both system-level testing under xEMU equivalent conditions and stability studies. The objectives are divided into four groups. The first set of tasks (Objective 1) are to synthesize, optimize and scale up the production of the candidate sorbents identified during Phase I. The next set of tasks (Objective 2) will focus on the development and implementation of test rigs to generate operating conditions that match the requirements of the xEMU with respect to the RCA unit. The test rigs will enable evaluation of the sorbent media before they will be provided to NASA for possible on-site evaluations. The next set of tasks (Objective 3) will be to characterize and evaluate the optimized sorbent medias at scale (equivalent bed size) under xEMU equivalent application and conditions (representative flow, CO2 and humidity concentrations). These will include bed length studies for extraction of mass transfer coefficients, swing bed performance tests, cycling of sorbents beds between air and vacuum. The final objective is to formalize the delivery and review of XploSafe’s prototype sorbents for evaluation by NASA.
Benefits: Successful development of the proposed technology will advance the state of the art in CO2 and humidity removal via a pressure swing adsorption system. As a part of the Exploration Portable Life Support System (xPLSS) and the Exploration Extra-vehicular Mobility Unit (xEMU) units, the platform technology will advance the viability of NASA's crewed deep space exploration objectives. Long service life CO2 scrubbers are desired in hospitals, clean rooms as well as industrial applications including mining and firefighting. Commercial demand arises from applications such as CO2 scrubbers in high altitude aerospace applications, recreational diving, submarines and rescue capsules.