Development of Carbon Dioxide Removal Systems for Advanced Exploration Systems

Abstract

"NASA's Advanced Exploration Systems (AES) program is pioneering new approaches for rapidly developing prototype systems, demonstrating key capabilities, and validating operational concepts for future human missions beyond Earth orbit" (NASA 2012). These forays beyond the confines of earth's gravity will place unprecedented demands on launch systems. They must not only blast out of earth's gravity well as during the Apollo moon missions, but also launch the supplies needed to sustain a crew over longer periods for exploration missions beyond earth's moon. Thus all spacecraft systems, including those for the separation of metabolic carbon dioxide and water from a crewed vehicle, must be minimized with respect to mass, power, and volume. Emphasis is also placed on system robustness both to minimize replacement parts and ensure crew safety when a quick return to earth is not possible. Current efforts are focused on improving the current state-of-the-art systems 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. These development efforts combine testing of sub-scale systems and multi-physics computer simulations to evaluate candidate approaches, select the best performing options, and optimize the configuration of the selected approach, which is then implemented in a full-scale integrated atmosphere revitalization test. This paper describes the carbon dioxide (CO2) removal hardware design and sorbent screening and characterization effort in support of the Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project within the AES program. A companion paper discusses development of atmosphere revitalization models and simulations for this project.

NASA Advanced Explorations Systems: 2018 Advancements in Life Support Systems

“…In test, a Catacel structured sorbent demonstrated slightly less CO2 removal rates than 4 kg/day of 2630 ppm CO2 using a high temperature of 170°C, a low pressure of only 0.4 psia and a rather slow cool down rate. These positive results show that the notion of a structured sorbent as a drop-in bed replacement for 4-Bed CO2 Scrubber is possible [9]. The LSS project plans for continued technological investment in FY2019.…”

“…The Structured Sorbents task intends to design a temperature swing adsorption (TSA) process that utilizes a structured 13X zeolite sorbent, ideally as a replacement for the 4-Bed CO2 Scrubber zeolite adsorbent bed. The 4-Bed CO2 Scrubber is a carbon dioxide removal system intended for demonstration on ISS in 2020 [9]. Structured adsorbents, when compared to packed beds, have lower pressure drop, higher mass transfer rates, resist fluidization and demonstrate improved thermal management.…”

Development of Carbon Dioxide Removal Systems for Advanced Exploration Systems 2012-2013

“…5. Comparative analyses of zeolites UOP RK-38 and UOP ASRT has shown that the RK-38 has an improved CO 2 removal capacity under ISS CDRA operational conditions. TGA, breakthrough, and equilibrium capacity testing all indicated an increased capacity.…”

“…Testing verified that the previous insulation, alumina paper, was neither thick enough nor compliant enough to prevent flow between the edge of the jelly roll and the ceramic plate. 2 More recently the adsorber was disassembled for visual inspection of the insulation, and replacement with a thicker, more compliant type. Follow-on velocity measurements confirmed that the bypass was virtually eliminated.…”

Flexible Path Environmental Control and Life Support Technology - An Updated Look at Next Steps

“…This lack of a consensus delays the start of significant vehicle and systems development, demonstrating the need of the flexible path approach and the ability to support multiple destinations with a common architecture and technology base. For systems such as ECLSS that require long lead times for technology maturation, systems development must start in the very near future in order to deploy usable and reliable systems in the intermediate (5)(6)(7)(8)(9)(10) year) future. Applying the flexible path philosophy will allow ECLSS development to commence absent a specific mission plan and destination goal.…”