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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Chemical reduction of CO2 is a needed function for Life Support during long term space travel. Such processes can create useful products such as oxygen, hydrocarbon fuels, and polymer feedstocks.
Temperature-swing adsorption pumps have been proposed as a method of acquiring and compressing Martian atmospheric CO2 for downstream processing. Most industrial applications and previous research targeted at space in-situ resource utilization (ISRU) utilize long (~hours) temperature swing periods, typically limited by the ability to transfer heat from a naturally insulating sorbent bed. A rapid cycle adsorption pump (RCAP) would reduce these periods to minutes, in the hope of increasing overall throughput. This paper details the design and preliminary experimental results from testing an RCAP in a simulated Martian environment. The test configuration features a central, liquid-cooled and heated heat transfer plate surrounded by symmetrical rectangular sorbent beds. Various bed thicknesses and commercially available Zeolite 13X sorbent particle sizes are evaluated to both determine performance and provide data for a parallel modeling effort. Discussions of multi-stage configurations and methods of boosting bed conductivity are included.
A database of heating and pressure measurements on a 7-deg half-angle cone in a highenthalpy expansion tunnel in CO2 has been generated to support development and validation of computational models to be employed in the design of future Mars missions. Laminar, transitional, and turbulent simulations were performed at the test conditions for comparisons with the data. Close agreement was obtained for both fully-laminar and fully turbulent conditions. For the remaining transitional/turbulent conditions, agreement to within, or slightly more than, the estimated experimental uncertainty was demonstrated. The influence of transition intermittency and transition length models on predicted heating levels was demonstrated, as were differences in turbulent heating predictions generated using various algebraic, one-equation, and two-equation turbulence models. These comparisons provide some measure of confidence in turbulent simulation capabilities; however, because the data were not obtained on a relevant entry vehicle geometry, it is not possible to fully quantify computational uncertainties for the definition of Mars mission aerothermodynamic environments at this time
Temperature-swing adsorption pumps have been proposed as a method of acquiring and compressing Martian atmospheric CO2 for downstream processing. Most industrial applications and previous research targeted at space in-situ resource utilization (ISRU) utilize long (~hours) temperature swing periods, typically limited by the ability to transfer heat from a naturally insulating sorbent bed. A rapid cycle adsorption pump (RCAP) would reduce these periods to minutes, in the hope of increasing overall throughput. This paper details the design and preliminary experimental results from testing an RCAP in a simulated Martian environment. The test configuration features a central, liquid-cooled and heated heat transfer plate surrounded by symmetrical rectangular sorbent beds. Various bed thicknesses and commercially available Zeolite 13X sorbent particle sizes are evaluated to both determine performance and provide data for a parallel modeling effort. Discussions of multi-stage configurations and methods of boosting bed conductivity are included.
Total column measurements of CO2 (XCO2) have been proposed as a possible way to estimate emissions from large urban regions. Using calculations from the Weather Research and Forecasting (WRF) model with a 1km emissions field, we investigate the viability of both real and proposed observing systems consisting of surface and/or column measurements for constraining emission sources of various types and sizes in the San Francisco Bay Area. We find that column observations are best suited for assessing enhancements downwind of very large emissions sources. For smaller sources (such as highways), in situ surface monitors are required to provide sufficient sensitivity. We explore methods for estimating emissions from the real and simulated observations.
Rising atmospheric CO2 concentrations necessitate deeper understanding of urban sources and sinks. Various sensor technologies and data assimilation strategies can be used to determine short- and long-term atmospheric trends. We seek to find the optimal synthesis of various measurement types in order to characterizing different types of sources in an urban environment.
Emission estimates of carbon dioxide (CO2) and methane (CH4) and the meteorological factors affecting them are investigated over Sacramento, California, using an aircraft equipped with a cavity ring-down greenhouse gas sensor as part of the Alpha Jet Atmospheric eXperiment (AJAX) project. To better constrain the emission fluxes, we designed flights in a cylindrical pattern and computed the emission fluxes from two flights using a kriging method and Gauss’s divergence theorem. Differences in wind treatment and assumptions about background concentrations affect the emission estimates by a factor of 1.5 to 7. The uncertainty is also impacted by meteorological conditions and distance from the emission sources. The vertical layer averaging affects the flux estimate, but the choice of raw wind or mass-balanced wind is more important than the thickness of the vertical averaging for massbalanced wind for both urban and local scales. The importance of vertical mass transfer for flux estimates is examined, and the difference in the total emission estimate with and without vertical mass transfer is found to be small, especially at the local scale. The total flux estimates accounting for the entire circumference are larger than those based solely on measurements made in the downwind region. This indicates that a closed-shape flight profile can better contain total emissions relative to a one-sided curtain flight because most cities have more than one point source and wind direction can change with time and altitude. To reduce the uncertainty of the emission estimate, it is important that the sampling strategy account not only for known source locations but also possible unidentified sources around the city. Our results highlight that aircraft-based measurements using a closed-shape flight pattern are an efficient and useful strategy for identifying emission sources and estimating local- and city-scale greenhouse gas emission fluxes.
Carbon capture and storage has been a research area of great interest in recent years asa method for mitigation of CO2emissions, due to the effects of climate change. The development of technologies for the efficient capture of CO2are also of great interest for human spaceflight applications. One of the most promising technologies in this area is CO2 scrubbing using liquid amines, unfortunately, liquid amines with low heats of desorption tend to have slow CO2binding kinetics. One potential solution to this problem is to use the enzyme carbonic anhydrase (CA) to enhance the kinetics of CO2binding to liquid amines, allowing the overall process to be more energy efficient. Interest in using carbonic anhydrase as a biocatalyst has led to a number of efforts to improve the thermostability and solvent tolerance of several distinct carbonic anhydrase enzymes. In the work described here, we screened through a diverse set of natural carbonic anhydrases to identify candidates for protein engineering aimed at increased stability and activity in various liquid amines. We then used SCHEMA structure-guided recombination to develop a set of chimeric carbonic anhydrases with high thermostability and activity. These chimeras were used as the starting points for further protein engineering work targeting activity in liquid amine systems. Our ultimate goal is to test the engineered enzymes in a liquid amine system for cabin air revitalization on ISS or other spacecraft.
The Four Bed Carbon Dioxide (4BCO2) scrubber Air-Save Pump (ASP) operates as part of the adsorbent bed regeneration cycle. The ASP removes residual air from the bed for return to the cabin prior to heat and vacuum exposure which drives out the CO2 regenerating the bed. 4BCO2 employs a Commercial Off-the-Shelf (COTS) scroll type air pump, repackaged in an acoustically insulated enclosure to reduce noise and mounted to a cold plate. The International Space Station (ISS) Low Temperature Loop (LTL) flow (operating between 38°F and 50°F) first cools the process air, and then flows through the cold plate, cooling the pump. This results in competing ASP thermal design goals: (1) to keep the pump and motor sufficiently cool and (2) to avoid forming condensation due to over-cooling. Surfaces below 60°F typically warrant careful consideration of condensation. A test-calibrated thermal model demonstrates such a balanced design is feasible with temperatures above 60°F. A separate, coupled fluid model predicts the potential for condensation formation, allowing risk assessment of flying with the unmodified design.
Statistical emulation allows combining advantageous features of statistical and process-based crop models for understanding the effects of future climate changes on crop yields. We describe here the development of emulators for nine process-based crop models and five crops using output from the Global Gridded Model Intercomparison Project (GGCMI) Phase 2. The GGCMI Phase 2 experiment is designed with the explicit goal of producing a structured training dataset for emulator development that samples across four dimensions relevant to crop yields: atmospheric carbon dioxide (CO2) concentrations, temperature, water supply, and nitrogen inputs (CTWN). Simulations are run under two different adaptation assumptions: that growing seasons shorten in warmer climates, and that cultivar choice allows growing seasons to remain fixed. The dataset allows emulating the climatological-mean yield response of all models with a simple polynomial in mean growing-season values. Climatological-mean yields are a central metric in climate change impact analysis; we show here that they can be captured without relying on interannual variations. In general, emulation errors are negligible relative to differences across crop models or even across climate model scenarios; errors become significant only in some marginal lands where crops are not currently grown. We demonstrate that the resulting GGCMI emulators can reproduce yields under realistic future climate simulations, even though the GGCMI Phase 2 dataset is constructed with uniform CTWN offsets, suggesting that the effects of changes in temperature and precipitation distributions are small relative to those of changing means. The resulting emulators therefore capture relevant crop model responses in a lightweight, computationally tractable form, providing a tool that can facilitate model comparison, diagnosis of interacting factors affecting yields, and integrated assessment of climate impacts.
Pharmaceuticals are an essential component of the medical system for crewed missions. Current research has identified decreased stability in space-flown pharmaceuticals compared to ground controls, and this presents a significant risk for future exploration-class missions where resupply will be limited. While the cause is not known, the elevated ambient carbon dioxide (CO2) in the spacecraft atmosphere has been postulated as a potential cause.
Long-term changes to the Quasi-Biennial Oscillation (QBO) remain uncertain. Recent multimodel investigations (Richter et al. 2020a, Butchart et al. 2020) suggest that QBO amplitude will weaken in the future, but trends in QBO period and stability are unclear. Additionally, the parameterizations that generate the QBO in CMIP6 models vary greatly, and about half of CMIP6 models do not represent the QBO at all (Richter et al. 2020b). Tropical convection is likely to play a role in QBO trends, yet a majority of gravity wave parameterizations in QBO-resolving models are fixed and cannot respond to changes in convection. We consider future changes of the QBO using the NASA Goddard Institute for Space Studies (GISS) Model E2.2, which has a realistic QBO produced partly through use of a non-orographic gravity wave drag scheme that explicitly links lower stratospheric momentum fluxes to convection (Rind et al., 2014, 2020; Orbe et al. 2020). The experiments include historical integrations and abrupt increases in CO which we use to probe the roles of convection and SST feedbacks. Overall, both the QBO period and amplitude decrease in response to CO2, and our results link the period response to changes in convection and the amplitude response to changes in upwelling.
This UNT Senior design team was tasked by NASA to develop a variable conductance thermal radiator prototype for CO2 deposition for deep space transit. NASA selects university teams every year to partake in the X-HAB Academic Innovation Challenge, with this year’s number of teams being six. Air Revitalization is a crucial system for any space travel, be it for Low Earth Orbit, such as the International Space Station, or for deep space transit. Current systems, such as the Carbon Dioxide Removal Apparatus aboard the ISS, require upkeep and maintenance, which cannot be done on long distance space missions. For the past several years, NASA has done research on Cryogenic systems for Carbon Dioxide removal. These systems operate on the fact that Carbon Dioxide freezes at a higher temperature than Oxygen and Nitrogen, so Carbon Dioxide can be frozen out of the cabin atmosphere without the use of filters, which degrade over time. To cool the cabin air down to a temperature where Carbon Dioxide freezes, Stirling cryocoolers have been used, which have shown promise in the hope of Carbon Dioxide deposition for Cabin Air Revitalization. Cryogenic systems are much more reliable but require significant energy input to operate. Physical systems, such as radiators, have generally not been used for this task, as there is a need to be able to “turn off” the rejection of heat to allow the frozen carbon dioxide to be collected. However, with working fluids pumped through a physical radiator, that aspect of operation can be achieved. The goal of this challenge is to determine the effectiveness of a variable conductance thermal radiator that can reject heat to deep space, without the use of a dedicated cryocooler to remove energy from the cabin air. The proposed design uses piping, hot and cold working fluids, and non-condensable gas to absorbl heat from the cabin air on one side of the radiator and reject the heat to deep space by means of thermal radiation. As well, the system will allow for the recovery of deposited Carbon Dioxide. The UNT X-HAB 2021 team will create a model radiator and test its performance with simulated heat sources and sinks and extrapolate those data points to analyze for real world conditions.
Our study suggests that the global CO2 fertilization effect (CFE) on vegetation photosynthesis has declined during the past four decades. The Comments suggest that the temporal inconsistency in AVHRR data and the attribution method undermine the results’ robustness. Here, we provide additional evidence that these arguments did not affect our finding and that the global decline in CFE is robust.
A new test series was performed in the Electric Arc Shock Tube (EAST) facility, with the aim of reproducing flight conditions encountered during the Mars2020 mission entry into Mars atmosphere. For this test series, the EAST facility was instrumented with two spectrometers for Optical Emission Spectroscopy (OES) measurements and three mid-infrared lasers for Tunable Diode Laser Absorption Spectroscopy (TDLAS). This study focuses on the spectrally and spatially resolved radiance measured with OES. Comparison with CEA/NEQAIR and DPLR/NEQAIR simulations were made. For velocity above 2.7 km/s, measurements are found to lie between the different tested kinetic models, within ± 10%. Below 2.7 km/s, the chemistry appears to be frozen and measured radiance profiles are typically 10% above CEA predictions. This difference is explained by shock deceleration effects. Finally, comparison between OES and TDLAS data are made and show a good agreement on the measured temperature and CO2 number density profiles using the two diagnostics, typically within 10 and 5%, respectively.
A new test series was performed in the Electric Arc Shock Tube (EAST) facility, with the aim of reproducing flight conditions encountered during the Mars2020 mission entry into Mars atmosphere. For this test series, the EAST facility was instrumented with two spectrometers for Optical Emission Spectroscopy (OES) measurements and three mid-infrared lasers for Tunable Diode Laser Absorption Spectroscopy (TDLAS). This study focuses on the spectrally and spatially resolved radiance measured with OES. Comparison with CEA/NEQAIR and DPLR/NEQAIR simulations were made. For velocity above 2.7 km/s, measurements are found to lie between the different tested kinetic models, within ± 10%. Below 2.7 km/s, the chemistry appears to be frozen and measured radiance profiles are typically 10% above CEA predictions. This difference is explained by shock deceleration effects. Finally, comparison between OES and TDLAS data are made and show a good agreement on the measured temperature and CO2 number density profiles using the two diagnostics, typically within 10 and 5%, respectively.
The ECLSS Digital Twin is a cloud-based simulation of the Four-Bed CO2 Scrubber, currently one of the primary means of removing carbon dioxide onboard the International Space Station, that operationalizes SME-developed multi-physics models and replicates conditions of the actual hardware in near real-time. In addition to providing insight into the system’s performance, it will enable prognostics, diagnostics, predictive maintenance, and simulated off-nominal scenarios. By leveraging digital representations, projects can save resources and gain a better understanding of their physical systems with the goal of building robust and reliable hardware for future deep space exploration. The use of data infrastructure in the cloud allows for streamlined analysis and visualization on a much larger scale than is possible with current tools.
The disclosure describes a pelletized sorbent comprising a first component comprising Basic Immobilized Amine Sorbent, a second component comprising inorganic strength additive, and a third component comprising polymer binder, where the Basic Immobilized Amine Sorbent and solid inorganic strength additive are interconnected by the polymer binder. The pelletized sorbent is useful for removing CO2 from a gaseous mixture such as a post combustion gas stream.