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A novel system is described for Sorption Cryocooling to 10 K, using hydrogen as refrigerant fluid, sorbent beds of metal hydride powders, and thermal compression and expansion. Current status is summarized of sorption cryocooler development for space applications requiring cooling of infrared and submillimeter sensors to 10 K and below. Several design variations, challenges, and predictions are discussed.
In NASA's Vision for Space Exploration (Bush, 2004), (Griffin, 2007), humans will once again travel beyond the confines of earth's gravity, this time to remain there for extended periods. These forays 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 liftoff the supplies needed to sustain a larger crew over much longer periods. 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. For short-term phases of manned space exploration, such as transit from the earth to the moon, venting of metabolic carbon dioxide and water to space is more efficient than the inclusion of large recycling systems on the spacecraft. The baseline system for the Orion spacecraft is an amine-based vacuum swing system (Smith, Perry et aI., 2006). As part of the development of an alternative approach, a sorbent-based CO2 and H2O removal system (Knox, Adams et aI., 2006), subscale testing was conducted to evaluate potential performance improvements obtainable by recuperating the heat of adsorption to aid in vacuum desorption. This bed design is shown in Figure 1, is depicted here with a lattice structure instead of reticulated foam for heat transfer. The slot widths are approximately 1.2 mm wide and 8.5 mm long. Bed depth is approximately 4.7 mm. Headers (not shown) were produced by the stereo lithography apparatus at MSFC.
An amine-based carbon dioxide (CO2) and water vapor sorbent in pressure-swing regenerable beds has been developed by Hamilton Sundstrand and baselined for the Atmosphere Revitalization System (ARS) for moderate duration missions of the Orion Multipurpose Crew Vehicle. The Orion ARS is designed to support not only open-cabin operations, tests of which have been reported in previous years at this conference, but also closed space suit-loop operations. A previous low-pressure suit loop test was performed with a human metabolic simulator, and humans wearing emergency masks were tested in a closed-loop configuration before that. In late 2011, simple tests were performed in a suit-loop configuration with human test subjects in prototype space suits with prototype umbilicals at ambient and two slightly above-ambient pressures. Trace contaminant filters and a prototype blower were also incorporated into the test rig. This paper discusses the performance of the ARS technology in that 2011 test configuration.
This document serves as the Final Report for Iowa State University's Space Habitat group to fulfill the specifications of NASA's eXploration Systems and Habitation (X-Hab) 2019 Academic Innovation Challenge for the 'Implementation of Advanced Sorbents in a Carbon Dioxide Management Unit' portion of the challenge. The scope of this document includes a description of the current Carbon Dioxide management systems implemented on ISS, a description of the group’s design, a description of the operational environment and scenarios, risks and mitigations, performance and testing results of the system, outreach, and future work.
The Carbon Dioxide Reduction Assembly (CRA) designed and developed for the International Space Station (ISS) represents the state-of-the-art in carbon dioxide reduction (CDRe) technology. The CRA produces water and methane by reducing carbon dioxide with hydrogen via the Sabatier reaction. The water is recycled to the Oxygen Generation Assembly (OGA) and the methane is vented overboard resulting in a net loss of hydrogen. The proximity to earth and the relative ease of logistics resupply from earth allow for a semi-closed system on ISS. However, long-term manned space flight beyond low earth orbit (LEO) dictates a more thoroughly closed-loop system involving significantly higher recovery of hydrogen, and subsequent recovery of oxygen, to minimize costs associated with logistics resupply beyond LEO. The open-loop ISS system for CDRe can be made closed-loop for follow-on missions by further processing methane to recover hydrogen. For this purpose, a process technology has been developed that employs a microwave-generated plasma to reduce methane to hydrogen and acetylene resulting in 75% theoretical recovery of hydrogen. In 2009, a 1-man equivalent Plasma Pyrolysis Assembly (PPA) was delivered to the National Aeronautics and Space Administration (NASA) for technical evaluation. The PPA has been integrated with a Sabatier Development Unit (SDU). The integrated process configuration incorporates a sorbent bed to eliminate residual carbon dioxide and water vapor in the Sabatier methane product stream before it enters the PPA. This paper provides detailed information on the stand-alone and integrated performance of both the PPA and SDU. Additionally, the integrated test stand design and anticipated future work are discussed.
The Volatile Organics Concentrator (VOC) system, designed to attach to a gas chromatograph/mass spectrometer (GC/MS) for the analyses of volatile organic compounds in water on Space Station Freedom, is described. Organic volatiles are collected and concentrated in the VOC by means of two primary solid sorbent tubes and desorbed into the GC/MS system. The paper describes the results of testing the VOC breadboard using a GC/MS system. Evaluations performed on 39 organic compounds recovered from water samples were compared with data for these compounds using direct injection/GC/MS and purge and trap/GC/MS procedures. The results demonstrate that the VOC/GC/MS system's detection limits for the 39 compounds analyzed are comparable to those of the EPA Method 524.2, and for many compounds reaching a factor of 5 lower.
To support continued manned space exploration, the development of atmosphere revitalization systems that are lightweight, compact, durable, and power efficient is a key challenge. The systems should be adaptable for use in a variety of habitats and should offer operational functionality to either expel removed constituents or capture them for closedloop recovery. As mission durations increase and exploration goals reach beyond low earth orbit, the need for regenerable adsorption processes for continuous removal of CO2 and trace contaminants from cabin air becomes critical. Precision Combustion, Inc. (PCI) and NASA Marshall (MSFC) have been developing an Engineered Structured Sorbents (ESS) approach based on PCI s patented Microlith technology to meet the requirements of future, extended human spaceflight explorations. This technology offers the inherent performance and safety attributes of zeolite and other sorbents with greater structural integrity, regenerability, and process control, thereby providing potential durability and efficiency improvements over current state-of-the-art systems. The major advantages of the ESS explored in this study are realized through the use of metal substrates to provide structural integrity (i.e., less partition of sorbents) and enhanced thermal control during the sorption process. The Microlith technology also offers a unique internal resistive heating capability that shows potential for short regeneration time and reduced power requirement compared to conventional systems. This paper presents the design, development, and performance results of the integrated adsorber modules for removing CO2, water vapor, and trace chemical contaminants. A related effort that utilizes the adsorber modules for sorption of toxic industrial chemicals is also discussed. Finally, the development of a 4-person two-leg ESS system for continuous CO2 removal is also presented.
This paper summarizes ongoing experiments characterizing the ability of critical sorption cryocooler components to achieve highly reliable operation for long-life space missions. Test data obtained over the past several years at JPL are entirely consistent with achieving ten year life for sorption compressors, electrical heaters, container materials, valves, and various sorbent materials suitable for driving 8 to 180 K refrigeration stages. Test results for various compressor systems are reported. Planned future tests necessary to gain a detailed understanding of the sensitivity of cooler performance and component life to operating constraints, design configurations, and fabrication, assembly and handling techniques, are also discussed.
Desulfurization of the hot reformate gas produced by catalytic partial oxidation or autothermal reforming of heavy fuels, such as JP-8 and jet fuels, is required prior to using the gas in a solid oxide fuel cell (SOFC). Development of suitable sorbent materials involves the identification of sorbents with favorable sulfidation equilibria, good kinetics, and high structural stability and regenerability at the SOFC operating temperatures (650 to 800 C). Over the last two decades, a major barrier to the development of regenerable desulfurization sorbents has been the gradual loss of sorbent performance in cyclic sulfidation and regeneration at such high temperatures. Mixed oxide compositions based on ceria were examined in this work as regenerable sorbents in simulated reformate gas mixtures and temperatures greater than 650 C. Regeneration was carried out with dilute oxygen streams. We have shown that under oxidative regeneration conditions, high regeneration space velocities (greater than 80,000 h(sup -1)) can be used to suppress sulfate formation and shorten the total time required for sorbent regeneration. A major finding of this work is that the surface of ceria and lanthanan sorbents can be sulfided and regenerated completely, independent of the underlying bulk sorbent. This is due to reversible adsorption of H2S on the surface of these sorbents even at temperatures as high as 800 C. La-rich cerium oxide formulations are excellent for application to regenerative H2S removal from reformate gas streams at 650 to 800 C. These results create new opportunities for compact sorber/regenerator reactor designs to meet the requirements of solid oxide fuel cell systems at any scale.
Topics covered include: Analysis of SSEM Sensor Data Using BEAM; Hairlike Percutaneous Photochemical Sensors; Video Guidance Sensors Using Remotely Activated Targets; Simulating Remote Sensing Systems; EHW Approach to Temperature Compensation of Electronics; Polymorphic Electronic Circuits; Micro-Tubular Fuel Cells; Whispering-Gallery-Mode Tunable Narrow-Band-Pass Filter; PVM Wrapper; Simulation of Hyperspectral Images; Algorithm for Controlling a Centrifugal Compressor; Hybrid Inflatable Pressure Vessel; Double-Acting, Locking Carabiners; Position Sensor Integral with a Linear Actuator; Improved Electromagnetic Brake; Flow Straightener for a Rotating-Drum Liquid Separator; Sensory-Feedback Exoskeletal Arm Controller; Active Suppression of Instabilities in Engine Combustors; Fabrication of Robust, Flat, Thinned, UV-Imaging CCDs; Chemical Thinning Process for Fabricating UV-Imaging CCDs; Pseudoslit Spectrometer; Waste-Heat-Driven Cooling Using Complex Compound Sorbents; Improved Refractometer for Measuring Temperatures of Drops; Semiconductor Lasers Containing Quantum Wells in Junctions; Phytoplankton-Fluorescence-Lifetime Vertical Profiler; Hexagonal Pixels and Indexing Scheme for Binary Images; Finding Minimum-Power Broadcast Trees for Wireless Networks; and Automation of Design Engineering Processes.
Processes to remove and recover carbon dioxide (CO2) and water vapor from air are essential for successful long-duration space missions. This paper presents results of a developmental program focused on the use of a liquid-sorbent/membrane-contactor (LSMC) system for removal of CO2 and water vapor from air. In this system, air from the spacecraft cabin atmosphere is circulated through one side of a hollow-fiber membrane contactor. On the other side of the membrane contactor is flowed a liquid sorbent, which absorbs the CO2 and water vapor from the feed air. The liquid sorbent is then heated to desorb the CO2 and water vapor. The CO2 is subsequently removed from the system as a concentrated gas stream, whereas the water vapor is condensed, producing a water stream. A breadboard system based on this technology was designed and constructed. Tests showed that the LSMC breadboard system can produce a CO2 stream and a liquid-water stream. Details are presented on the operation of the system, as well as the effects on performance of variations in feed conditions.
Results from research on catalytic recombination of CO-O2 for stable closed-cycle operation of CO2 lasers hold much promise for a variety of technology transfer. Expansion of CO2 laser remote sensing applications toward chemical detection and pollution monitoring would certainly be expected. However, the catalysts themselves may be especially effective in low-temperature oxidation of a number of chemicals in addition to CO. It is therefore of interest to compare the CO-O2 catalysts with chemical systems designed for chemical sensing, air purification and process catalysis. Success in understanding the catalytic mechanisms of the recombination of CO-O2 could help to shed light on how catalyst systems operate. New directions in low-temperature oxidation catalysts, coatings for chemical sensors and sorbents for air purification could well emerge.
Aboard the International Space Station, CO2 is removed from the cabin atmosphere by a four-bed molecular sieve (4BMS) process called the Carbon Dioxide Removal Assembly (CDRA).1 This 4BMS process operates by passing the CO2-laden air through a desiccant bed to remove any humidity and then passing the dried air through a sorbent bed to remove the CO2. While one pair of beds is in use, the other pair is thermally regenerated to allow for continuous CO2 removal.
Utilizing liquid amines for air revitalization applications has been of continued interest for many decades. They have the advantage of being regenerable sorbents with long lifetimes and a high acuteness for carbon dioxide. While their usage on Earth for flue gas and submarines has been explored for some time now, they are still being researched for use in microgravity environments. To succeed in a microgravity environment, such as usage on the International Space Station, an air revitalization system that is reliant on liquid amines as its sorbent must have a low Equivalent System Mass (ESM), among many other performance parameters. One way of optimizing this ESM number is through bringing down the systems power consumption with the use of microwave heating of the liquid sorbent. Microwave heating allows the liquid sorbent to be heated in a much more efficient way when compared to conventional types of heating techniques, such as convection or conduction. This paper will explore the physical mechanisms behind microwave heating, and how it could potentially be applied to a liquid amine carbon capture system, laying out any concerns and future constraints that a system designer may encounter.
The primary focus of Kennedy Space Center's gas separation activities has been for carbon dioxide, nitrogen, and argon used in oxygen production technologies for Martian in-situ resource utilization (ISRU) projects. Recently, these studies were expanded to include oxygen for regenerative life support systems. Since commercial membrane systems have been developed for separation of carbon dioxide, nitrogen, and oxygen, initially the studies focused on these membrane systems, but at lower operating temperatures and pressures. Current investigations art examining immobilized liquids and solid sorbents that have the potential for higher selectivity and lower operating temperatures. The gas separation studies reported here use hollow fiber membranes to separate carbon dioxide, nitrogen, and argon in the temperature range from 230 to 300 K. Four commercial membrane materials were used to obtain data at low feed and permeate pressures. These data were used with a commercial solution-diffusion modeling tool to design a system to prepare a buffer gas from the byproduct of a process to capture Martian carbon dioxide. The system was designed to operate, at 230 K with a production rate 0.1 sLpm; Feed composition 30% CO2, 44% N2, and 26% Ar; Feed pressure 104 kPa (780); and Permeate pressure 1 kPa (6 torr); Product concentration 600 ppm CO2. This new system was compared with a similar system designed to operate at ambient temperatures (298 K). The systems described above, along with data, test apparatus, and models are presented.
An amine-based carbon dioxide (CO2) and water vapor sorbent in pressure-swing regenerable beds has been developed by Hamilton Sundstrand and baselined for the Orion Atmosphere Revitalization System (ARS). In three previous years at this conference, reports were presented on extensive Johnson Space Center (JSC) testing of this technology in a sea-level pressure environment with simulated and real human metabolic loads in both open and closed-loop configurations. The test article design was iterated a third time before the latest series of such tests, which was performed in the first half of 2009. The new design incorporates a canister configuration modification for overall unit compactness and reduced pressure drop, as well as a new process flow control valve that incorporates both compressed gas purge and dual-end vacuum desorption capabilities. This newest test article is very similar to the flight article designs. Baseline tests of the new unit were performed to compare its performance to that of the previous test articles. Testing of compressed gas purge operations helped refine launchpad operating condition recommendations developed in earlier testing. Operating conditions used in flight program computer models were tested to validate the model projections. Specific operating conditions that were recommended by the JSC test team based on past test results were also tested for validation. The effects of vacuum regeneration line pressure on resulting cabin conditions was studied for high metabolic load periods, and a maximum pressure is recommended.
An amine-based carbon dioxide (CO2) and water vapor sorbent in pressure-swing regenerable beds has been developed by Hamilton Sundstrand and baselined for the Orion Atmosphere Revitalization System (ARS). In three previous years at this conference, reports were presented on extensive Johnson Space Center (JSC) testing of this technology in a sea-level pressure environment, with simulated and real human metabolic loads, in both open and closed-loop configurations. The test article design was iterated a third time before the latest series of such tests, which was performed in the first half of 2009. The new design incorporates a canister configuration modification for overall unit compactness and reduced pressure drop, as well as a new process flow control valve that incorporates both compressed gas purge and dual-end vacuum desorption capabilities. This newest test article is very similar to the flight article designs. Baseline tests of the new unit were performed to compare its performance to that of the previous test articles. Testing of compressed gas purge operations helped refine launchpad operating condition recommendations developed in earlier testing. Operating conditions used in flight program computer models were tested to validate the model projections. Specific operating conditions that were recommended by the JSC test team based on past test results were also tested for validation. The effects of vacuum regeneration line pressure on resulting cabin conditions was studied for high metabolic load periods, and a maximum pressure is recommended
Spacecraft being developed for future exploration missions incorporate Environmental Control and Life Support Systems (ECLSS) that limit weight, power, and volume thus requiring systems with higher levels of efficiency while maintaining high dependability and robustness. For air revitalization, an approach that meets those goals utilizes a regenerative Vacuum-Swing Adsorption (VSA) system that removes 100% of the CO2 from the cabin atmosphere as well as 100% of the water. A Sorbent Based Atmosphere Revitalization (SBAR) system is a VSA system that utilizes standard commercial adsorbents that have been proven effective and safe in spacecraft including Skylab and the International Space Station. The SBAR system is the subject of a development, test, and evaluation program that is being conducted at NASA s Marshall Space Flight Center. While previous testing had validated that the technology is a viable option, potential improvements to system design and operation were identified. Modifications of the full-scale SBAR test articles and adsorption cycles have been implemented and have shown significant performance gains resulting in a decrease in the consumables required for a mission as well as improved mission safety. Previous testing had utilized single bed test articles, during this period the test facility was enhanced to allow testing on the full 2-bed SBAR system. The test facility simulates a spacecraft ECLSS and allows testing of the SBAR system over the full range of operational conditions using mission simulations that assess the real-time performance of the SBAR system during scenarios that include the metabolic transients associated with extravehicular activity. Although future manned missions are currently being redefined, the atmosphere revitalization requirements for the spacecraft are expected to be quite similar to the Orion and the Altair vehicles and the SBAR test program addressed validation to the defined mission requirements as well as operation in other potential vehicle architectures. The development program, including test articles, the test facility, and tests and results through early 2011 is discussed.