SBIR-STTR Award

NASA is interested in improving the method to control CO2 and water in the Exploration Extravehicular Mobility Unit (xEMU) to meet the ambitious objectives of the Artemis program, which includes human presence on the surface of the Moon and Mars. These levels must be controlled to established values of 2.2 mm Hg at a metabolic rate of 2.44 g/min. Historically, the Metox has been used to remove CO2 from the suit. The sorbent in the Metox has a finite capacity during an EVA and must be regenerated after the mission is complete. The capacity limits mission times, which can only be increased by making the Metox larger. The technology that is planned to replace the Metox is the RCA which utilizes two beds that are alternately used to remove CO2 and H2O and then regenerated by exposure to space vacuum. The RCA has been under development for over 10 years and has utilized an amine-based sorbent (SA9T). Although SA9T has good reversible CO2 uptakes, higher capacities are desired to maintain low CO2 levels and reduce O2 losses. In addition, this sorbent emits low levels of ammonia which must be removed from the suit using a separate technology. In this SBIR Phase I project, Reaction Systems will develop new sorbents that will outperform SA9T and at the same time exhibit reduced ammonia emissions. Reaction Systems’ strategy to accomplish this goal consists of two important components. The first component consists of identifying sorbents that have high probability to perform better than the SA9T. Reaction Systems has demonstrated expertise in the development of advanced sorbents for CO2 control in both EVA and cabin applications and will also employ a consultant who is an expert in gas surface interactions and in the synthesis and characterization of organic compounds. The second component of our strategy is the application of a rapid screening method that will provide accurate and relevant performance data so compounds with the highest potential can be quickly identified. Potential NASA Applications (Limit 1500 characters, approximately 150 words): This technology could be used for CO2 control in a space craft cabin or on the surface of the Moon or Mars (Artemis goals). The CDRA, used on the ISS for CO2 control, uses pressure and temperature swing adsorption cycle to remove CO2. The CO2 is removed with a mol sieve that is heated to 400°F during regeneration. The cycling causes the sorbent to break down into dust, which clogs filters or ends up in the cabin air. A sorbent that does not require a temperature increase for regeneration would reduce power consumption and eliminate dust. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): This could also be used for control of CO2 emissions from power plants. The concentration of CO2 in the atmosphere has increased from 280 ppm to over 400 ppm over the last 50 years primarily due to CO2 emissions from fossil fuel combustion. An effective method to remove CO2 could be used to remove CO2 from the effluent and compress it into a concentrated liquid for sequestration, storage, or use. Duration: 6

NASA is interested in improving the method to control CO2 and water in the Exploration Extravehicular Mobility Unit (xEMU) to meet the ambitious objectives of the Artemis program, which includes human presence on the surface of the Moon and Mars. The technology that is planned to be used is the RCA which utilizes two beds that are alternately used to remove CO2 and H2O and then are regenerated by exposure to space vacuum. The RCA utilizes an amine-based sorbent (SA9T), and although it has good reversible CO2 uptakes, higher capacities are desired to maintain lower CO2 levels and to reduce power consumption and O2 losses. In addition, this sorbent emits low levels of ammonia which must be removed from the suit using a separate technology. In the SBIR Phase I project, Reaction Systems successfully developed new sorbents that outperformed SA9T and reduced ammonia emissions. Tests carried out on selected sorbents and SA9T over a wide range of CO2 partial pressures indicated that a new sorbent had cycle times that were over a factor of two greater than for SA9T at the higher CO2 pressures, which results in a 44% reduction in number of half cycles in the Standard EVA. Ammonia emissions are also over an order of magnitude lower for the new sorbent compared to SA9T. In the Phase II project, Reaction Systems will continue developing the new sorbent to a TRL that will allow it to be incorporated into new space suits for advanced missions. Tasks include optimizing the composition and preparation, performing lifetime measurements, evaluating the effect that contaminants could have and finally testing at full scale. The full scale tests will be carried out in a custom CO2 control module similar in design to the RCA but will have more accessibility to the sorbent beds. In addition, the module will be installed in Reaction Systems’ full scale ventilation loop that can simulate pressures, flow rates, and humidity levels encountered in the suit during an EVA. Anticipated

Benefits:
In addition to its use in the space suit, this technology could be used for CO2 control in a space craft cabin. The current technology, the CDRA, uses pressure and temperature swing adsorption cycle to remove CO2 and the thermal cycling causes the molecular sieve sorbent to break down into dust particles, which clog filters or end up in the cabin air. A sorbent that does not require a temperature increase for regeneration could reduce power consumption and eliminate dust. The technology could also be used for control of CO2 emissions from power plants. The concentration of CO2 in the atmosphere has increased from 280 ppm to over 400 ppm over the last 50 years primarily due to CO2 emissions from fossil fuel combustion. An effective method could be used to remove CO2 from the effluent and compress it into a concentrated liquid for sequestration, storage, or use.