Browsing by Author "Knox, James C."
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Item Development of a Test for Evaluation of the Hydrothermal Stability of Sorbents used in Closed-Loop CO2 Removal Systems(45th International Conference on Environmental Systems, 2015-07-12) Knox, James C.; Gauto, Hernando; Miller, Lee A.The International Space Station Carbon Dioxide Removal Assembly uses zeolite 5A molecular sieve material packed into beds for the capture of cabin CO2. The beds are cyclically heated to drive off the CO2 and restore the removal capacity. Over time, the sorbent material has been found to break down resulting in dust that restricts flow through the beds. Humidity adsorbed in the 5A zeolite when it is heated is a suspected cause of this sorbent degradation. To evaluate the impact of adsorbed water during thermal cycling, the Hydrothermal Stability Test was developed. The test configuration provides comparative side-by-side flow restriction data for two sorbent materials at specifically controlled humidity levels. While the initial focus of the testing is on 5A zeolite materials currently used on the ISS, the system will also be used to evaluate future candidate materials. This paper describes the approach, the test system, current results, and future testing.Item Development of Carbon Dioxide Removal Systems for Advanced Exploration Systems 2013-2014(44th International Conference on Environmental Systems, 2014-07-13) Knox, James C.; Gauto, Hernando; Gostowski, Rudy; Watson, David; Bush, Richard; Miller, Lee; Stanley, Chris; Thomas, JohnThe Atmosphere Revitalization Recovery and Environmental Monitoring (ARREM) project was initiated in September of 2011 as part of the Ad- vanced Exploration Systems (AES) program. Under the ARREM project, CO2 removal and associated air drying efforts are focused on improving the current state-of-the-art systems utilizing fixed beds of sorbent pellets by seek- ing more robust pelletized sorbents, evaluating structured sorbents, and ex- amining alternate bed configurations to improve system efficiency and relia- bility. These development efforts combine sorbent screening and characteri- zation, testing of sub-scale and full-scale systems, and multi-physics comput- er simulations to evaluate candidate approaches, select the best performing options, and optimize the configuration of the selected approach. The select- ed subsystem is then implemented in a full-scale integrated atmosphere revi- talization test. This paper describes the carbon dioxide removal hardware design and sorbent screening and characterization effort in support of the ARREM project within the AES program. The development of CO2 removal and associated air-drying subsystem models and simulations under the AR- REM project is discussed in a companion paper.Item Development of Carbon Dioxide Removal Systems for Advanced Exploration Systems 2014-2015(45th International Conference on Environmental Systems, 2015-07-12) Knox, James C.; Coker, Robert; Huff, Timothy L.; Gatens, Robyn; Miller, Lee A.; Stanley, ChristineA long-term goal for NASA is to enable crewed missions to Mars: first to the vicinity of Mars, and then to the Mars surface. These missions present new challenges for all aspects of spacecraft design in comparison with the International Space Station, as resupply is unavailable in the transit phase, and early return is not possible. Additionally, mass, power, and volume must be minimized for all phases to reduce propulsion needs. Mass reduction is particularly crucial for Mars surface landing and liftoff due to the challenges inherent in these operations for even much smaller payloads. In this paper we describe current and planned developments in the area of carbon dioxide removal to support future crewed Mars missions. Activities are also described that apply to both the resolution of anomalies observed in the ISS CDRA and the design of life support systems for future missions.Item Evaluation of an Atmosphere Revitalization Subsystem for Deep Space Exploration Missions(45th International Conference on Environmental Systems, 2015-07-12) Perry, Jay L.; Abney, Morgan B.; Conrad, Ruth E.; Frederick, Kenneth R.; Greenwood, Zachary W.; Kayatin, Matthew J.; Knox, James C.; Newton, Robert L.; Parrish, Keith J.; Takada, Kevin C.; Miller, Lee A.; Scott, Joseph P.; Stanley, Christine M.An Atmosphere Revitalization Subsystem (ARS) suitable for deployment aboard deep space exploration mission vehicles has been developed and functionally demonstrated. This modified ARS process design architecture was derived from the International Space Station’s (ISS) basic ARS. Primary functions considered in the architecture include trace contaminant control, carbon dioxide removal, carbon dioxide reduction, and oxygen generation. Candidate environmental monitoring instruments were also evaluated. The process architecture rearranges unit operations and employs equipment operational changes to reduce mass, simplify, and improve the functional performance for trace contaminant control, carbon dioxide removal, and oxygen generation. Results from integrated functional demonstration are summarized and compared to the performance observed during previous testing conducted on an ISS-like subsystem architecture and a similarly evolved process architecture. Considerations for further subsystem architecture and process technology development are discussed.Item Optimization of the Carbon Dioxide Removal Assembly (CDRA-4EU) in Support of the International Space System and Advanced Exploration Systems(45th International Conference on Environmental Systems, 2015-07-12) Knox, James C.; Stanley, Christine M.The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The Carbon Dioxide (CO2) removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort utilizes a virtual Carbon Dioxide Removal Assembly, revision 4 (CDRA-4) test bed to test a large number of potential operational configurations with independent variations in flow rate, cycle time, heater ramp rate, and set point. Initial ground testing will provide prerequesite source data and provide baseline data in support of the virtual CDRA. Once the configurations with the highest performance and lowest power requirements are determined by the virtual CDRA, the results will be confirmed by testing these configurations with the CDRA-4EU ground test hardware. This paper describes the initial ground testing of select configurations. The development of the virtual CDRA under the AES-LSS Project will be discussed in a companion paper.Item Sorbent Structural Impacts due to Humidity on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems(45th International Conference on Environmental Systems, 2015-07-12) Watson, David; Knox, James C.; West, Phillip; Stanley, Christine M.; Bush, RichardThe Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The CO2 removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort encompasses structural stability testing of existing and emerging sorbents. Testing will be performed on dry sorbents and sorbents that have been conditioned to three humidity levels. This paper describes the sorbent structural stability screening efforts in support of the LSS Project within the AES Program.