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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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NASA NTRS2005

The Flora Mission for Ecosystem Composition, Disturbance and Productivity

Global land use and climate variability alter ecosystem conditions - including structure, function, and biological diversity - at a pace that requires unambiguous observations from satellite vantage points. Current global measurements are limited to general land cover, some disturbances, vegetation leaf area index, and canopy energy absorption. Flora is a pathfinding mission that provides new measurements of ecosystem structure, function, and diversity to understand the spatial and temporal dynamics of human and natural disturbances, and the biogeochemical and physiological responses of ecosystems to disturbance. The mission relies upon high-fidelity imaging spectroscopy to deliver full optical spectrum measurements (400-2500 nm) of the global land surface on a monthly time step at 45 meter spatial resolution for three years. The Flora measurement objectives are: (i) fractional cover of biological materials, (ii) canopy water content, (iii) vegetation pigments and light-use efficiency, (iv) plant functional types, (v) fire fuel load and fuel moisture content, and (vi) disturbance occurrence, type and intensity. These measurements are made using a multi-parameter, spectroscopic analysis approach afforded by observation of the full optical spectrum. Combining these measurements, along with additional observations from multispectral sensors, Flora will far advance global studies and models of ecosystem dynamics and change.

Asner, Gregory P.↗

NASA NTRS2002

Ice Cloud Formation and Dehydration in the Tropical Tropopause Layer

Stratospheric water vapor is important not only for its greenhouse forcing, but also because it plays a significant role in stratospheric chemistry. Several recent studies have focused on the potential for dehydration due to ice cloud formation in air rising slowly through the tropical tropopause layer (TTL). Holton and Gettelman showed that temperature variations associated with horizontal transport of air in the TTL can drive ice cloud formation and dehydration, and Gettelman et al. recently examined the cloud formation and dehydration along kinematic trajectories using simple assumptions about the cloud properties. In this study, a Lagrangian, one-dimensional cloud model has been used to further investigate cloud formation and dehydration as air is transported horizontally and vertically through the TTL. Time-height curtains of temperature are extracted from meteorological analyses. The model tracks the growth, advection, and sedimentation of individual cloud particles. The regional distribution of clouds simulated in the model is comparable to the subvisible cirrus distribution indicated by SAGE II. The simulated cloud properties and cloud frequencies depend strongly on the assumed supersaturation threshold for ice nucleation. The clouds typically do not dehydrate the air along trajectories down to the temperature minimum saturation mixing ratio. Rather the water vapor mixing ratio crossing the tropopause along trajectories is 10-50% larger than the saturation mixing ratio. I will also discuss the impacts of Kelvin waves and gravity waves on cloud properties and dehydration efficiency. These simulations can be used to determine whether observed lower stratospheric water vapor mixing ratios can be explained by dehydration associated with in situ TTL cloud formation alone.

Jensen, Eric↗

NASA NTRS1972

Study of water recovery and solid waste processing for aerospace and domestic applications. Volume 1: Final report summary

This study of water reclamation and waste disposal is directed toward a more efficient utilization of natural resources. From an ecological standpoint improved methods of land use, water processing equipment, and ideal population profiles are investigated. Methods are described whereby significant reduction in water usage can be achieved by the adoption of presently available and practically applied technological concepts. Allowances are made for social, natural, and economic contingencies which are likely to occur up to the year 2000.

Guarneri, C. A.↗

NASA NTRS1975

Thermochemical production of hydrogen via multistage water splitting processes

This paper presents and reviews the fundamental thermodynamic principles underlying thermochemical water splitting processes. The overall system is considered first and the temperature limitation in process thermal efficiency is developed. The relationship to an ideal water electrolysis cell is described and the nature of efficient multistage reaction processes is discussed. The importance of the reaction entropy change and the relation of the reaction free energy change to the work of separation is described. A procedure for analyzing thermochemical water splitting processes is presented and its use to calculate individual stage efficiency is demonstrated. A number of processes are used to illustrate the concepts and procedures.

Funk, J. E.↗

NASA NTRS1997

In-Situ Propellant Production on Mars: A Sabatier/Electrolysis Demonstration Plant

An efficient, reliable propellant production plant has been developed for use on Mars. Using a Sabatier reactor in conjunction with a water electrolysis system, a complete demonstration plant has produced methane and liquid oxygen from simulated Martian atmosphere. The production plant has demonstrated high efficiency, extended duration production and autonomous operations. This paper presents the results and conclusions relating to eventual use in a Mars sample return mission. This work was funded by the Jet Propulsion Laboratory (JPL). The production plant was built and tested at the Propulsion Center of Lockheed Martin at the Denver Colorado facility.

Clark, David L.↗

NASA NTRS1993

Single element injector cold flow testing for STME swirl coaxial injector element design

An oxidizer-swirled coaxial element injector is being investigated for application in the Space Transportation Main Engine (STME). Single element cold flow experiments were conducted to provide characterization of the STME injector element for future analysis, design, and optimization. All tests were conducted to quiescent, ambient backpressure conditions. Spray angle, circumferential spray uniformity, dropsize, and dropsize distribution were measured in water-only and water/nitrogen flows. Rupe mixing efficiency was measured using water/sucrose solution flows with a large grid patternator for simple comparative evaluation of mixing. Factorial designs of experiment were used for statistical evaluation of injector geometrical design features and propellant flow conditions on mixing and atomization. Increasing the free swirl angle of the liquid oxidizer had the greatest influence on increasing the mixing efficiency. The addition of gas assistance had the most significant effect on reducing oxidizer droplet size parameters and increasing droplet size distribution. Increasing the oxidizer injection velocity had the greatest influence for reducing oxidizer droplet size parameters and increasing size distribution for non-gas assisted flows. Single element and multi-element subscale hot fire testing are recommended to verify optimized designs before committing to the STME design.

Hulka, J.↗

NASA NTRS2006

Testing of an Amine-Based Pressure-Swing System for Carbon Dioxide and Humidity Control

Hamilton Sundstrand has developed a stable and efficient amine-based carbon dioxide (CO2) and water vapor (H2O) sorbent, SA9T, that is well-suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads, and the flows are all controlled with a single spool valve. The SA9T sorbent technology has already been baselined for the new Orion spacecraft. However, more data was needed on the operational characteristics of the package in a simulated spacecraft environment. This amine-based technology, referred to as the CO2 And Moisture Removal Amine Swing-bed (CAMRAS) by the Exploration Life Support Air Team at Johnson Space Center (JSC), was tested at JSC during the last third of 2006. Two series of tests on the CAMRAS were performed at simulated metabolic loads of four and/or six crewmen in a closed chamber. Tests were run at a variety of cabin temperatures and with a range of operating conditions varying cycle time, available vacuum pressure, blower speed, and crew activity levels. Results of this testing are presented and potential flight operational strategies discussed.

Lin, Amy B.↗

NASA NTRSDate not supplied

The PACE-MAPP Polarized Ocean Bio-optical Model

The MAPP polarimeter retrieval algorithm, originally developed for the airborne NASA GISS Research Scanning Polarimeter, is being adapted to the PACE observing system to allow for a simultaneous retrieval of aerosol, thin cirrus, and ocean products using both PACE polarimeters and the OCI shortwave infrared channels. Here, we describe the polarized ocean bio-optical model we have developed for PACE-MAPP, which is designed to use a combination of homogenous and coated spheres to more accurately model the absorption and backscattering properties of algal and non-algal particles, and which also includes absorption by colored dissolved organic matter. We first use Lorenz-Mie computations to create lookup tables to accurately and efficiently characterize the optical properties of homogeneous and coated spheres embedded in water for PACE. We then use these lookup tables to develop a bio-optical model that consists of an external mixture of homogeneous (non-algal) and coated (algal) spheres. Lastly, we use the bio-optical model in forward radiative transfer computations to perform inversions of MODIS remote sensing reflectance for a variety of ocean regions. We explore the sensitivity of these inversions to ocean constituent inherent optical properties.

James Allen↗

NASA NTRS1977

Solafern solar system design brochure

A complete residential solar space heating and hot water system is described. Low maintenance, durable, and efficient air heating collectors are used. The collectors have a selective absorber and a tempered glass cover nearly one-quarter of an inch thick with an aluminum frame. The solar energy can be delivered directly to the living area when there is a demand; otherwise, it is stored in the form of hot water. Hot water storage is accomplished through the use of an air-to-water exchanger. The hot water storage is used simultaneously to preheat the domestic hot water, as well as to store energy for space heating.

Source record↗

NASA NTRS2009

Filtering Water by Use of Ultrasonically Vibrated Nanotubes

Devices that could be characterized as acoustically driven molecular sieves have been proposed for filtering water to remove all biological contaminants and all molecules larger than water molecules. Originally intended for purifying wastewater for reuse aboard spacecraft, these devices could also be attractive for use on Earth in numerous settings in which there are requirements to obtain potable, medical-grade, or otherwise pure water from contaminated water supplies. These devices could also serve as efficient means of removing some or all water from chemical products . for example, they might be useful as adjuncts or substitutes for stills in the removal of water from alcohols and alcoholic beverages. These devices may be constructed using various materials, such as ceramics, metallics, or polymers, depending on end-use requirements. A representative device of this type (see figure) would include a polymeric disk, about 1 mm in diameter and between 1 and 40 microns thick, within which would be embedded single-wall carbon nanotubes aligned along the thickness axis. The polymeric disk would be part of a unitary polymeric ring assembly. An acoustic transducer in the form of a piezoelectric-film-and-electrode subassembly - typically 9 microns thick and made of poly(vinylidene fluoride) coated with copper 150 nm thick -. would be affixed to the outside of the outer polymeric ring by means of an electrically nonconductive epoxy. The nanotubes would be chosen to have diameters between about 8 and about 13.5 A because water molecules could fit into the nanotubes, but larger molecules could not. Water to be purified would be placed in contact with one face (typically, the upper face) of the filter disk. The surface tension of water is low enough that water molecules should enter and travel along the nanotubes, and computational simulations of molecular dynamics and experimental measurements have shown that the water molecules inside the nanotubes in this size range can be expected to become aligned into helical columns that exhibit properties of both hexagonal ice crystals and liquid water

Gavalas, Lillian Susan↗

NASA NTRS2004

New Hydrophilic, Composite Membranes for Air Removal from Water Coolant Systems

Liquid coolants are commonly used as thermal transport media to increase efficiency and flexibility in aerospace vehicle design. The introduction of gas bubbles into the coolant can have negative consequences, including: loss of centrifugal pump prime, irregular sensor readings, and blockage of coolant flow to remote systems. One solution to mitigate these problems is the development of a passive gas removal device, or gas trap, installed in the flight cooling system. In this study, a new hydrophilic, composite membrane has been developed for passage of the coolant fluid and retention of gas bubbles. The trapped bubbles are subsequently vented from the system by a thin, hydrophobic, microporous membrane. The original design for this work employed a homogeneous membrane that was susceptible to fouling and pore plugging. Spare gas traps of this variety have degraded during storage, and recreation of the membranes has been complicated due to problems with polymer duplication and property variations in the final membranes. In this work, replacements have been developed based on deposition of a hydrophilic polymer on the bore-side of a porous polyethylene (PE) tube. The tube provides excellent chemical and mechanical stability, and the hydrophilic layer provides retention of gas bubbles. Preliminary results have shown that intimate contact is required between the deposited layer and the substrate to overcome material differences. This has been accomplished by presoaking the membrane tube in the solvent to raise its surface energy. Polymer solutions of various concentrations have been used to promote penetration of the polymer layer into the porous substrate and to control separation layer thickness. The resulting composite membranes have shown repeatable decrease in nitrogen permeability, which is indicative of a decrease in membrane pore size. Studies with water permeation have yielded similar results. We have observed some swelling of the added polymer layer, which causes a slight decrease in membrane pore size, and should result in improved bubble retention. Preliminary studies have also been performed on gas retention in flowing systems. Initial results have been promising, with negligible gas permeation for the coated membranes compared to 100% gas permeation in the uncoated tube.

Ritchie, Stephen M. C.↗

NASA NTRS2007

Is There Water on the Moon? NASA's LCROSS Mission

NASA is preparing for its return to the moon with the Lunar CRater Observation and Sensing Satellite (LCROSS) mission. This secondary payload spacecraft will travel with the Lunar Reconnaissance Orbiter (LRO) satellite to the Moon on the same Atlas-V 401 Centaur rocket launched from Cape Canaveral Air Force Station, Florida. The LCROSS mission will robotically seek to determine the presence of water ice at the Moon's South Pole. The 1000kg Secondary Payload budget is efficiently used to provide a highly modular and reconfigurable LCROSS Spacecraft with extensive heritage to accurately guide the expended Centaur into the crater. Upon separation, LCROSS flies through the impact plume, telemetering real-time images and characterizing water ice in the plume with infrared cameras and spectrometers. LCROSS then becomes a 700kg impactor itself, to provide a second opportunity to study the nature of the Lunar Regolith. LCROSS provides a critical ground-truth for Lunar Prospector and LRO neutron and radar maps, making it possible to assess the total lunar water inventory. This presentation contains a reference to video animation of the LCROSS mission that will be covered separately.

Noneman, Steven↗

NASA NTRS2014

"Efficiency Space" - A Framework for Evaluating Joint Evaporation and Runoff Behavior

At the land surface, higher soil moisture levels generally lead to both increased evaporation for a given amount of incoming radiation (increased evaporation efficiency) and increased runoff for a given amount of precipitation (increased runoff efficiency). Evaporation efficiency and runoff efficiency can thus be said to vary with each other, motivating the development of a unique hydroclimatic analysis framework. Using a simple water balance model fitted, in different experiments, with a wide variety of functional forms for evaporation and runoff efficiency, we transform net radiation and precipitation fields into fields of streamflow that can be directly evaluated against observations. The optimal combination of the functional forms the combination that produces the most skillful stream-flow simulations provides an indication for how evaporation and runoff efficiencies vary with each other in nature, a relationship that can be said to define the overall character of land surface hydrological processes, at least to first order. The inferred optimal relationship is represented herein as a curve in efficiency space and should be valuable for the evaluation and development of GCM-based land surface models, which by this measure are often found to be suboptimal.

GCM↗

NASA NTRSDate not supplied

Thermal Model of Ice Growth in Vacuum for Lunar Water Production

To support NASA’s goal of sustained lunar presence, the use of in-situ resource utilization will reduce launch weight and frequency of resupply missions. With the discovery of water in the permanently shadowed regions of the moon, the prospect of harvesting water has generated particular interest. A more fundamental understanding of water storage and capture in lunar conditions is necessary for effective and efficient water capture and transport. The present study derives a thermal model for ice height, heat flux, chamber pressure, and mass flow rate in sub-atmospheric pressures below the triple point. The thermal model compares ice layer height against the results of the experiment at two pressures (300 Pa and 500 Pa) and temperatures from -18°C to -3°C. The thermal model predicts the trends seen experimentally with an overall root mean square error of 0.1135 cm and coefficient of efficiency of 0.994, indicating the model predicts the experimental results. The thermal model can be utilized to examine the impacts of varying pressure, temperature, and cold plate area to determine the most effective ice growth conditions for efficient capture of water on the lunar surface. The thermal model will provide a useful tool for NASA in the design of the lunar ice tanker and shows the promise of effective capture water on the lunar surface.

Ice growth↗

NASA NTRSDate not supplied

Thermal Model of Ice Growth in Vacuum for Lunar Water Production

Ice growth↗

NASA NTRS1982

Brushless Cleaning of Solar Panels and Windows

Machine proposed for cleaning solar panels and reflectors uses multiple vortexes of air, solvent, and water to remove dust and dirt. Uses no brushes that might abrade solar surfaces and thereby reduce efficiency. Machine can be readily automated and can be used on curved surfaces such as aparbolic reflectors as well as on flat ones. Cleaning fluids are recycled, so that large quantities of water and solvent are not needed.

Schneider, H. W.↗

NASA NTRS2005

Water Injection Feasibility for Boeing 747 Aircraft

Can water injection be offered at a reasonable cost to large airplane operators to reduce takeoff NO( sub x) emissions? This study suggests it may be possible. This report is a contract deliverable to NASA Glenn Research Center from the prime contractor, The Boeing Commercial Airplane Company of Seattle, WA. This study was supported by a separate contract to the Pratt & Whitney Engine Company of Hartford, CT (contract number NNC04QB58P). Aviation continues to grow and with it, environmental pressures are increasing for airports that service commercial airplanes. The feasibility and performance of an emissions-reducing technology, water injection, was studied for a large commercial airplane (e.g., Boeing 747 with PW4062 engine). The primary use of the water-injection system would be to lower NOx emissions while an important secondary benefit might be to improve engine turbine life. A tradeoff exists between engine fuel efficiency and NOx emissions. As engines improve fuel efficiency, by increasing the overall pressure ratio of the engine s compressor, the resulting increased gas temperature usually results in higher NOx emissions. Low-NO(sub x) combustors have been developed for new airplanes to control the increases in NO(sub x) emissions associated with higher efficiency, higher pressure ratio engines. However, achieving a significant reduction of NO(sub x) emissions at airports has been challenging. Using water injection during takeoff has the potential to cut engine NO(sub x) emissions some 80 percent. This may eliminate operating limitations for airplanes flying into airports with emission constraints. This study suggests an important finding of being able to offer large commercial airplane owners an emission-reduction technology that may also save on operating costs.

Daggett, David L.↗

NASA NTRS2012

Sensitivity of Cirrus and Mixed-phase Clouds to the Ice Nuclei Spectra in McRAS-AC: Single Column Model Simulations

The salient features of mixed-phase and ice clouds in a GCM cloud scheme are examined using the ice formation parameterizations of Liu and Penner (LP) and Barahona and Nenes (BN). The performance of LP and BN ice nucleation parameterizations were assessed in the GEOS-5 AGCM using the McRAS-AC cloud microphysics framework in single column mode. Four dimensional assimilated data from the intensive observation period of ARM TWP-ICE campaign was used to drive the fluxes and lateral forcing. Simulation experiments where established to test the impact of each parameterization in the resulting cloud fields. Three commonly used IN spectra were utilized in the BN parameterization to described the availability of IN for heterogeneous ice nucleation. The results show large similarities in the cirrus cloud regime between all the schemes tested, in which ice crystal concentrations were within a factor of 10 regardless of the parameterization used. In mixed-phase clouds there are some persistent differences in cloud particle number concentration and size, as well as in cloud fraction, ice water mixing ratio, and ice water path. Contact freezing in the simulated mixed-phase clouds contributed to transfer liquid to ice efficiently, so that on average, the clouds were fully glaciated at T approximately 260K, irrespective of the ice nucleation parameterization used. Comparison of simulated ice water path to available satellite derived observations were also performed, finding that all the schemes tested with the BN parameterization predicted 20 average values of IWP within plus or minus 15% of the observations.

Betancourt, R. Morales↗