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All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

Atmospheric Carbon Cycle Dynamics Over the Above Domain: an Integrated Analysis Using Aircraft Observations (Arctic-CA) and Model Simulations (GEOS)

The Arctic Carbon Atmospheric Profiles (Arctic-CAP) project conducted six airborne surveys of Alaska and northwestern Canada between April and November 2017 to capture the spatial and temporal gradients of northern high-latitude carbon dioxide (CO2), methane (CH4) and carbon monoxide (CO) as part of NASA's Arctic-Boreal Vulnerability Experiment (ABoVE). The Arctic-CAP sampling strategy involved acquiring vertical profiles of CO2, CH4 and CO from the surface to 5 km altitude at 25 sites around the ABoVE domain on a 4- to 6-week time interval. We observed vertical gradients of CO2, CH4 and CO that vary by eco-region and duration of the sampling period, which spanned the majority of the seasonal cycle. All Arctic-CAP measurements were compared to a global simulation using the Goddard Earth Observing System (GEOS) modeling system. Comparisons with GEOS simulations of atmospheric CO2, CH4 and CO highlight the potential of these multi-species observations to inform improvements in surface flux estimates and the representation of atmospheric transport. GEOS simulations provide estimates of the near surface average CO2 and CH4 enhancements that are well correlated with aircraft observations (R=0.74 and R=0.60 respectively), suggesting that GEOS has reasonable fidelity over this complex and heterogeneous region. This model-data comparison over the ABoVE domain reveals that while current state-of-the-art models and flux estimates are able to capture broadscale spatial and temporal patterns in near-surface CO2 and CH4 concentrations, more work is needed to resolve fine-scale flux features that are observed. The study also provides a framework for benchmarking a global model at regional scales, which is needed to use climate models as tools to investigate high-latitude carbon-climate feedbacks.

C Sweeney↗
NASA NTRS1998

Simulation of Long Lived Tracers Using an Improved Empirically Based Two-Dimensional Model Transport Algorithm

We have developed a new empirically-based transport algorithm for use in our GSFC two-dimensional transport and chemistry model. The new algorithm contains planetary wave statistics, and parameterizations to account for the effects due to gravity waves and equatorial Kelvin waves. As such, this scheme utilizes significantly more information compared to our previous algorithm which was based only on zonal mean temperatures and heating rates. The new model transport captures much of the qualitative structure and seasonal variability observed in long lived tracers, such as: isolation of the tropics and the southern hemisphere winter polar vortex; the well mixed surf-zone region of the winter sub-tropics and mid-latitudes; the latitudinal and seasonal variations of total ozone; and the seasonal variations of mesospheric H2O. The model also indicates a double peaked structure in methane associated with the semiannual oscillation in the tropical upper stratosphere. This feature is similar in phase but is significantly weaker in amplitude compared to the observations. The model simulations of carbon-14 and strontium-90 are in good agreement with observations, both in simulating the peak in mixing ratio at 20-25 km, and the decrease with altitude in mixing ratio above 25 km. We also find mostly good agreement between modeled and observed age of air determined from SF6 outside of the northern hemisphere polar vortex. However, observations inside the vortex reveal significantly older air compared to the model. This is consistent with the model deficiencies in simulating CH4 in the northern hemisphere winter high latitudes and illustrates the limitations of the current climatological zonal mean model formulation. The propagation of seasonal signals in water vapor and CO2 in the lower stratosphere showed general agreement in phase, and the model qualitatively captured the observed amplitude decrease in CO2 from the tropics to midlatitudes. However, the simulated seasonal amplitudes were attenuated too rapidly with altitude in the tropics. Overall, the simulations with the new transport formulation are in substantially better agreement with observations compared with our previous model transport.

Fleming, E. L.↗
NASA NTRS2012

Global CO2 Distributions over Land from the Greenhouse Gases Observing Satellite (GOSAT)

January 2009 saw the successful launch of the first space-based mission specifically designed for measuring greenhouse gases, the Japanese Greenhouse gases Observing SATellite (GOSAT). We present global land maps (Level 3 data) of column-averaged CO2 concentrations (X(sub CO2)) derived using observations from the GOSAT ACOS retrieval algorithm, for July through December 2009. The applied geostatistical mapping approach makes it possible to generate maps at high spatial and temporal resolutions that include uncertainty measures and that are derived directly from the Level 2 observations, without invoking an atmospheric transport model or estimates of CO2 uptake and emissions. As such, they are particularly well suited for comparison studies. Results show that the Level 3 maps for July to December 2009 on a lO x 1.250 grid, at six-day resolution capture much of the synoptic scale and regional variability of X(sub CO2), in addition to its overall seasonality. The uncertainty estimates, which reflect local data coverage, X(sub CO2) variability, and retrieval errors, indicate that the Southern latitudes are relatively well-constrained, while the Sahara Desert and the high Northern latitudes are weakly-constrained. A probabilistic comparison to the PCTM/GEOS-5/CASA-GFED model reveals that the most statistically significant discrepancies occur in South America in July and August, and central Asia in September to December. While still preliminary, these results illustrate the usefulness of a high spatiotemporal resolution, data-driven Level 3 data product for direct interpretation and comparison of satellite observations of highly dynamic parameters such as atmospheric CO2.

Hammerling, Dorit M.↗
NASA NTRS2012

Z-1 Prototype Space Suit Testing Summary

The Advanced Space Suit team of the NASA-Johnson Space Center performed a series of test with the Z-1 prototype space suit in 2012. This paper discusses, at a summary level, the tests performed and results from those tests. The purpose of the tests were two -fold: 1) characterize the suit performance so that the data could be used in the downselection of components for the Z -2 Space Suit and 2) develop interfaces with the suitport and exploration vehicles through pressurized suit evaluations. Tests performed included isolated and functional range of motion data capture, Z-1 waist and hip testing, joint torque testing, CO2 washout testing, fit checks and subject familiarizations, an exploration vehicle aft deck and suitport controls interface evaluation, delta pressure suitport tests including pressurized suit don and doff, and gross mobility and suitport ingress and egress demonstrations in reduced gravity. Lessons learned specific to the Z -1 prototype and to suit testing techniques will be presented.

Ross, Amy J.↗
NASA NTRS2013

Z-1 Prototype Space Suit Testing Summary

The Advanced Space Suit team of the NASA-Johnson Space Center performed a series of test with the Z-1 prototype space suit in 2012. This paper discusses, at a summary level, the tests performed and results from those tests. The purpose of the tests were two-fold: 1) characterize the suit performance so that the data could be used in the downselection of components for the Z-2 Space Suit and 2) develop interfaces with the suitport and exploration vehicles through pressurized suit evaluations. Tests performed included isolated and functional range of motion data capture, Z-1 waist and hip testing, joint torque testing, CO2 washout testing, fit checks and subject familiarizations, an exploration vehicle aft deck and suitport controls interface evaluation, delta pressure suitport tests including pressurized suit don and doff, and gross mobility and suitport ingress and egress demonstrations in reduced gravity. Lessons learned specific to the Z-1 prototype and to suit testing techniques will be presented.

Ross, Amy↗
NASA NTRS2012

Nanoporous Materials in Atmosphere Revitalization

Atmospheric Revitalization (AR) is the term the National Aeronautics and Space Administration (NASA) uses to encompass the engineered systems that maintain a safe, breathable gaseous atmosphere inside a habitable space cabin. An AR subsystem is a key part of the Environmental Control and Life Support (ECLS) system for habitable space cabins. The ultimate goal for AR subsystem designers is to 'close the loop', that is, to capture gaseous human metabolic products, specifically water vapor (H2O) and Carbon dioxide (CO2), for maximal Oxygen (o2) recovery and to make other useful resources from these products. The AR subsystem also removes trace chemical contaminants from the cabin atmosphere to preserve cabin atmospheric quality, provides O2 and may include instrumentation to monitor cabin atmospheric quality. Long duration crewed space exploration missions require advancements in AR process technologies in order to reduce power consumption and mass and to increase reliability compared to those used for shorter duration missions that are typically limited to Low Earth Orbit. For example, current AR subsystems include separate processors and process air flow loops for removing metabolic CO2 and volatile organic tract contaminants (TCs). Physical adsorbents contained in fixed, packed beds are employed in these processors. Still, isolated pockets of high carbon dioxide have been suggested as a trigger for crew headaches and concern persists about future cabin ammonia (NH3) levels as compared with historical flights. Developers are already focused on certain potential advancements. ECLS systems engineers envision improving the AR subsystem by combining the functions of TC control and CO2 removal into a single regenerable process and moving toward structured sorbents - monoliths - instead of granular material. Monoliths present a lower pressure drop and eliminate particle attrition problems that result from bed containment. New materials and configurations offer promise for lowering cabin levels of CO2 and NH3 as well as reducing power requirements and increasing reliability. This chapter summarizes the challenges faced by ECLS system engineers in pursuing these goals, and the promising materials developments that may be part of the technical solution for challenges of crewed space exploration beyond LEO.

Hernandez-Maldonado, J.↗
NASA NTRS2015

Simulation Apps Bring Us Closer to Mars

My work with mathematical modeling and computer simulations began in earnest in 1987 when I signed on with the National Aeronautics and Space Administration, better known as NASA. At the time I was developing computer simulations to support the design of carbon dioxide (CO2) removal systems for the International Space Station (ISS) life support system. CO2 is a human metabolic waste, produced at a rate of a kilogram per day per crewmember. CO2 must be removed from the crew cabin, as it will quickly become detrimental to crew health. The systems used to remove CO2 are typically based on sorption processes, which include complex interactions of heat transfer, mass transfer, and gas flow through porous media. At this time, there were no commercial options for solving a set of coupled mathematical models such as partial differential equations (PDEs); you either force-fit the physics into a thermal analysis package or wrote your own code, complete with discretization, meshing, and solution algorithms. Unfortunately, coding CO2 removal processes from scratch did not allow an appropriate focus on the challenging yet crucial task of understanding and capturing the underlying physics via appropriate mathematical models. Configuration control was often simply ignored due to tight schedules, resulting in a code that would be quicker for a second party to rewrite than modify. In the early 2000s, I decided to move CO2 removal simulations to a platform with built-in meshing, solvers, and postprocessing capabilities, and that could solve user-defined multiphysics PDEs. The program chosen to meet these needs was COMSOL Multiphysics®. Along with freeing the engineer to focus on the underlying physics, a degree of configuration control was automatically achieved via a consistent user interface, thus allowing COMSOL users to share computer models. My team has developed simulations that are already providing a valuable debugging capability for the ISS CO2 removal system, and will provide guidance in upgrades to that system.

Knox, Jim↗
NASA NTRS2012

The Geostationary Fourier Transform Spectrometer

The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for an earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. The GeoFTS instrument is a half meter cube size instrument designed to operate in geostationary orbit as a secondary "hosted" payload on a commercial geostationary satellite mission. The advantage of GEO is the ability to continuously stare at a region of the earth, enabling frequent sampling to capture the diurnal variability of biogenic fluxes and anthropogenic emissions from city to continental scales. The science goal is to obtain a process-based understanding of the carbon cycle from simultaneous high spatial resolution measurements of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and chlorophyll fluorescence (CF) many times per day in the near infrared spectral region to capture their spatial and temporal variations on diurnal, synoptic, seasonal and interannual time scales. The GeoFTS instrument is based on a Michelson interferometer design with a number of advanced features incorporated. Two of the most important advanced features are the focal plane arrays and the optical path difference mechanism. A breadboard GeoFTS instrument has demonstrated functionality for simultaneous measurements in the visible and IR in the laboratory and subsequently in the field at the California Laboratory for Atmospheric Remote Sensing (CLARS) observatory on Mt. Wilson overlooking the Los Angeles basin. A GeoFTS engineering model instrument is being developed which will make simultaneous visible and IR measurements under space flight like environmental conditions (thermal-vacuum at 180 K). This will demonstrate critical instrument capabilities such as optical alignment stability, interferometer modulation efficiency, and high throughput FPA signal processing. This will reduce flight instrument development risk and show that the GeoFTS design is mature and flight ready.

Carbon exchanges↗
NASA NTRS2012

Microwave Extraction of Volatiles for Mars Science and ISRU

The greatest advantage of microwave heating for volatiles extraction is that excavation can be greatly reduced. Surface support operations would be simple consisting of rovers with drilling capability for insertion of microwaves down bore holes to heat at desired depths. The rovers would also provide support to scientific instruments for volatiles analysis and for volatiles collection and storage. The process has the potential for a much lower mass and a less complex system than other in-situ processes. Microwave energy penetrates the surface heating within with subsequent sublimation of water or decomposition of volatile containing minerals. On Mars the volatiles should migrate to the surface to be captured with a cold trap. The water extraction and transport process coupled with atmospheric CO2 collection could readily lead to a propellant production process, H2O + CO2 yields CH4 + O2.

Ethridge, Edwin C.↗
NASA NTRSDate not supplied

Comparison of Alternative Configurations of an Integrated Open-Loop Carbon Dioxide Removal System using Liquid Amine

Several carbon dioxide removal systems are being investigated for applications in microgravity. The liquid amine wedge system utilizes the capillary action of liquids to prevent the mixing of the air and liquid while still allowing for carbon dioxide capture at their interface. A one crew mission requires approximately 1 kg per day of carbon dioxide removal to prevent adverse health effects. A proposed design of a wedge tray system can be improved from the initial testing parameters to achieve the required carbon dioxide capture for one crew. The wedge trays in the contactor can be organized in either a parallel configuration to accumulate less CO2 in the liquid but at a higher flow rate or a series configuration to yield a higher weight percentage of CO2 in the liquid but at a lower flow rate. The gas flow rate and composition were held constant at 26scfm and 2600ppm, respectively, due to constraints of other proposed systems but the liquid flow rate was adjusted between 0.1mL/min and 10mL/min. The flow rate that yielded the best carbon dioxide capture was X mL/min and Y mL/min for the parallel and series configurations, respectively. The degasser temperature and pressure were varied from 80 to 100°C and 0 and -3 inHg. The largest carbon dioxide flux of Z kg/day/m2 was observed at a contactor liquid flow rate of X mL/min and a degasser temperature and pressure of T°C and P inHg.

Adrian Cortez↗
NASA NTRS2004

Exploring the limits of crop productivity: beyond the limits of tipburn in lettuce

The productivity of lettuce in a combination of high light, high temperature, and elevated CO2 has not been commonly studied because rapid growth usually causes a calcium deficiency in meristems called tipburn, which greatly reduces quality and marketability. We eliminated tipburn by blowing air directly onto the meristem, which allowed us to increase the photosynthetic photon flux (PPF) to 1000 micromoles m-2 s-1 (57.6 mol m-2 d-1); two to three times higher than normally used for lettuce. Eliminating tipburn doubled edible yield at the highest PPF level. In addition to high PPF, CO2 was elevated to 1200 micromoles m-2 mol-1, which increased the temperature optimum from 25 to 30 degrees C. The higher temperature increased leaf expansion rate, which improved radiation capture and more than doubled yield. Photosynthetic efficiency, measured as canopy quantum yield in a whole-plant gas exchange system, steadily increased up to the highest temperature of 32 degrees C in high CO2. The highest productivity was 19 g m-2 d-1 of dry biomass (380 g d-1 fresh mass) averaged over the 23 days the plants received light. Without the limitation of tipburn, the combination of high PPF, high temperature, and elevated CO2 resulted in a 4-fold increase in growth rate over productivity in conventional environments.

NASA Discipline Life Support Systems↗
NASA NTRS2011

A Model Study of the Impact of Source Gas Changes on the Stratosphere for 1850-2100

The long term stratospheric impacts due to emissions of CO2, CH4, N2O, and ozone depleting substances (ODSs) are investigated using an updated version of the Goddard two-dimensional (2D) model. Perturbation simulations with the ODSs, CO2, CH4, and N2O varied individually are performed to isolate the relative roles of these gases in driving stratospheric changes over the 1850-2100 time period. We also show comparisons with observations and the God- 40 dard Earth Observing System chemistry-climate model simulations for the time period 1970-2100 to illustrate that the 2D model captures the basic processes responsible for longterm stratospheric change. The 2D simulations indicate that prior to 1940, the 45 ozone increases due to CO2 and CH4 loading outpace the ozone losses due to increasing N2O and carbon tetrachloride (CCl4) emissions, so that ozone reaches a broad maximum during the 1920s-1930s. This preceeds the significant ozone depletion during approx. 1960-2050 driven by the ODS loading. During the latter half of the 21st century as ODS emissions diminish, CO2, N2O, and CH4 loading will all have significant impacts on global total ozone based on the IPCC AIB (medium) scenario, with CO2 having the largest individual effect. Sensitivity tests illustrate that due to the strong chemical interaction between methane and chlorine, the CH4 impact on total ozone becomes significantly more positive with larger ODS loading. The model simulations also show that changes in stratospheric temperature, Brewer-Dobson circulation (BDC), and age of air during 1850-2100 are controlled mainly by the CO2 and ODS loading. The simulated acceleration of the BDC causes the age of air to decrease by approx. 1 year from 1860-2100. The corresponding photochemical lifetimes of N2O, CFCl3, CF2Cl2, and CCl4 decrease by 11-13% during 1960-2100 due to the acceleration of the BDC, with much smaller lifetime changes 4%) caused by changes in the photochemical loss rates.

Fleming, E. L.↗
NASA NTRS1992

Four simple ocean carbon models

This paper briefly reviews the key processes that determine oceanic CO2 uptake and sets this description within the context of four simple ocean carbon models. These models capture, in varying degrees, these key processes and establish a clear foundation for more realistic models that incorporate more directly the underlying physics and biology of the ocean rather than relying on simple parametric schemes. The purpose of this paper is more pedagogical than purely scientific. The problems encountered by current attempts to understand the global carbon cycle not only require our efforts but set a demand for a new generation of scientist, and it is hoped that this paper and the text in which it appears will help in this development.

Moore, Berrien, III↗
NASA NTRS2017

Atmospheric Capture On Mars (and Processing)

The ultimate destination of NASA's human exploration program is Mars. In Situ Resource Utilization (ISRU) is a key technology required to enable such missions, as first proposed by Prof. Robert Ash in 1976. This presentation will review progress in the systems required to produce rocket propellant, oxygen, and other consumables on Mars using the carbon dioxide atmosphere and other potential resources. For many years, NASA, commercial companies, and academia have been developing, and demonstrating techniques to capture and purify Martian atmospheric gases for their utilization for the production of hydrocarbons, oxygen, and water in ISRU systems. Other gases will be required to be separated from Martian atmospheric gases to provide pure CO2 for processing elements. Significant progress has been demonstrated in CO2 collection via adsorption by molecular sieves, freezing, and direct compression. Early stage work in adsorption in Ionic Liquids followed by electrolysis to oxygen is also underway. In addition, other Martian gases, such as nitrogen and argon, occur in concentrations high enough to be useful as buffer gas and could be captured as well. Gas separation requirements include, but are not limited to the selective separation of: (1) methane and water from unreacted carbon oxides (CO2-CO) and hydrogen typical of a Sabatier-type process, (2) carbon oxides and water from unreacted hydrogen from a Reverse Water-Gas Shift process, and (3) carbon oxides from oxygen from a trash/waste processing reaction.

propellant production↗
NASA NTRSDate not supplied

A Gene Expression and Histologic Approach to Study Production and Outflow of Cerebrospinal Fluid in Hindlimb Suspended Rats

INTRODUCTION: The Spaceflight Associated Neuro-ocular Syndrome (SANS) is thought to be associated with weightlessness-induced cephalad fluid shift, possibly associated with a chronic elevation of intracranial pressure (ICP) during long-duration ISS missions. Changes in cerebrospinal fluid (CSF) dynamics and cranial compliance might be involved in the ICP increase. It is not known whether CSF production and/or outflow are altered in microgravity, but changes at the molecular and cellular level in the structures that produce and regulate the transcellular and paracellular secretion and reabsorption of CSF may be relevant. In this study, we used the rat hindlimb suspension (HS) model to examine the relationship between intracranial pressure (ICP) and the cellular responses to the prolonged change in body posture elicited specifically in the choroid plexus (CP). This was evaluated by transcriptomics, histopathology and ultrastructure of the CP and arachnoid villi (AV). METHODS: ICP was measured by telemetry. The morphology, ultrastructure, and gene expression profile of the CP was examined using male 9-month-old Long Evans rats subjected to HS for 14 and 90 days. A subset of animals completing 90-day HS returned to normal posture for 14 and 90 additional days of recovery. All HS rats had age-matched cage controls maintained in normal posture. A group of animals was maintained in conditions of 1% CO2 throughout the entire protocol. The rat brains were carefully removed and preserved for various analyses, including transmission electron microscopy (TEM), immunohistochemical analysis of specific targets involved in CSF regulation, and RNA sequencing analysis of laser capture micro-dissected CP tissue from the lateral ventricles. SUMMARY OF RESULTS: The ICP record was limited, which impacted any conclusions derived from the results. However, the ICP of rats in the CO2-enriched atmosphere appeared increased compared to those in a normal air composition. HS of rats resulted in an altered transcriptomics profile in the choroid plexus compared to animals maintained at normal posture. This was observed during both the HS period and during normal posture recovery period following 90 days of suspension. The greatest number of differentially expressed genes was observed at 90 days HS. Elevated CO2 also led to a different transcriptomics profile in the CP. The histology and ultrastructure results should be considered preliminary due to the limited number of samples. Examination of the CP by TEM showed blood vessel congestion and microvilli swelling in the CP, as well as some subpial and periventricular gliosis, but no associations were observed with treatment. There was no evidence of a reduced clearance of b-amyloid in the periventricular, perivascular and subpial regions of the brain in HS animals versus those in normal posture. Immunohistochemical staining of aquaporin 4, showed the localization to the subpial region and ependyma with increased immunoreactivity in the brains of CO2 exposed rats. This work was supported by awards NNX15AW48G to S.Z. Animal tissue and live data was provided under a tissue/data sharing agreement with Dr. Charles Fuller, UC Davis.

S B Zanello↗
NASA NTRSDate not supplied

A Gene Expression and Histologic Approach to Study Production and Outflow of Cerebrospinal Fluid in Hindlimb Suspended RATS

INTRODUCTION: The Spaceflight Associated Neuro-ocular Syndrome (SANS) is thought to be associated with weightlessness-induced cephalad fluid shift, possibly associated with a chronic elevation of intracranial pressure (ICP) during long-duration ISS missions. Changes in cerebrospinal fluid (CSF) dynamics and cranial compliance might be involved in the ICP increase. It is not known whether CSF production and/or outflow are altered in microgravity, but changes at the molecular and cellular level in the structures that produce and regulate the transcellular and paracellular secretion and reabsorption of CSF may be relevant. In this study, we used the rat hindlimb suspension (HS) model to examine the relationship between intracranial pressure (ICP) and the cellular responses to the prolonged change in body posture elicited specifically in the choroid plexus (CP). This was evaluated by transcriptomics, histopathology and ultrastructure of the CP and arachnoid villi (AV). METHODS: ICP was measured by telemetry. The morphology, ultrastructure, and gene expression profile of the CP was examined using male 9-month-old Long Evans rats subjected to HS for 14 and 90 days. A subset of animals completing 90-day HS returned to normal posture for 14 and 90 additional days of recovery. All HS rats had age-matched cage controls maintained in normal posture. A group of animals was maintained in conditions of 1% CO2 throughout the entire protocol. The rat brains were carefully removed and preserved for various analyses, including transmission electron microscopy (TEM), immunohistochemical analysis of specific targets involved in CSF regulation, and RNA sequencing analysis of laser capture micro-dissected CP tissue from the lateral ventricles. SUMMARY OF RESULTS: The ICP record was limited, which impacted any conclusions derived from the results. However, the ICP of rats in the CO2-enriched atmosphere appeared increased compared to those in a normal air composition. HS of rats resulted in an altered transcriptomics profile in the choroid plexus compared to animals maintained at normal posture. This was observed during both the HS period and during normal posture recovery period following 90 days of suspension. The greatest number of differentially expressed genes was observed at 90 days HS. Elevated CO2 also led to a different transcriptomics profile in the CP. The histology and ultrastructure results should be considered preliminary due to the limited number of samples. Examination of the CP by TEM showed blood vessel congestion and microvilli swelling in the CP, as well as some subpial and periventricular gliosis, but no associations were observed with treatment. There was no evidence of a reduced clearance of b-amyloid in the periventricular, perivascular and subpial regions of the brain in HS animals versus those in normal posture. Immunohistochemical staining of aquaporin 4, showed the localization to the subpial region and ependyma with increased immunoreactivity in the brains of CO2 exposed rats. This work was supported by awards NNX15AW48G to S.Z. Animal tissue and live data was provided under a tissue/data sharing agreement with Dr. Charles Fuller, UC Davis.

S B Zanello↗
NASA NTRS2019

Capturing Connections Between the Water, Energy, and Carbon Cycles with the NASA GEOS

Studying biosphere-atmosphere interactions is complex as water, energy and carbon cycles and their feedback processes have to be integrated. At NASA GMAO, we investigate these interactions with an Earth system model that allows us to explore and quantify relevant feedbacks associated with the exchanges of carbon, water, and energy fluxes within the atmosphere, within the land, and across the land-atmosphere interface. Current biosphere-atmosphere modeling research at GMAO includes a study to understand the relative contributions of land carbon flux variability and atmospheric dynamics to atmospheric CO2 variability in time and space. For this study, we use a unique capability of the NASA GEOS model, a "replay" mode that forces the model to reproduce the weather systems captured by the MERRA-2 reanalysis. Another study investigates the impact of imposed regional drought on land carbon fluxes and on subsequent atmospheric CO2 concentrations, thereby revealing interactions between the water and carbon cycles. Using the new coupled carbon-climate modeling capability, current GMAO efforts at subseasonal-to-seasonal forecasting are now being expanded, at least in research mode, to include forecasts of carbon and phenological state.

Lee, Eunjee↗
NASA NTRS2002

Membrane Separation Processes at Low Temperatures

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.

Parrish, Clyde↗