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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 NTRS1975

The development of a solar residential heating and cooling system

The MSFC solar heating and cooling facility was assembled to demonstrate the engineering feasibility of utilizing solar energy for heating and cooling buildings, to provide an engineering evaluation of the total system and the key subsystems, and to investigate areas of possible improvement in design and efficiency. The basic solar heating and cooling system utilizes a flat plate solar energy collector, a large water tank for thermal energy storage, heat exchangers for space heating, and an absorption cycle air conditioner for space cooling. A complete description of all systems is given. Development activities for this test system included assembly, checkout, operation, modification, and data analysis, all of which are discussed. Selected data analyses for the first 15 weeks of testing are included, findings associated with energy storage and the energy storage system are outlined, and conclusions resulting from test findings are provided. An evaluation of the data for summer operation indicates that the current system is capable of supplying an average of 50 percent of the thermal energy required to drive the air conditioner. Preliminary evaluation of data collected for operation in the heating mode during the winter indicates that nearly 100 percent of the thermal energy required for heating can be supplied by the system.

Source record↗

NASA NTRS1980

Urban solar photovoltaics potential: An inventory and modelling study applied to the San Fernando Valley region of Los Angeles

Procedures for analyzing the potential of solar photovoltaic collectors to meet energy requirements in a metropolitan region are described and a modeling effort is applied to the San Fernando Valley region of Los Angeles. The procedure involves a series of steps designed to produce maps and tabulations revealing the amount of rooftop area available for establishing solar collectors and the proportion of energy requirement that could be potentially supplied by solar photovoltaics within each of the 533 mainline feeder service areas in the study area. For the sixty five square mile study area, the results showed that, with half the available flat and south facing roofs used and assuming the availability of energy storage, 52.7 percent of the actual kWh energy requirements could have been met in 1978 using photovoltaic collectors. Hourly, daily, weekly, and monthly fluctuations in potential supply and actual loads and recommendations of avenues for further research are discussed. Some further potential applications of the modeling technique are suggested.

Angelici, G. L.↗

NASA NTRS1981

Observations of solar irradiance variability

High-precision measurements of total solar irradiance, made by the active cavity radiometer irradiance monitor on the Solar Maximum Mission satellite, show the irradiance to have been variable throughout the first 153 days of observations. The corrected data resolve orbit-to-orbit variations with uncertainties as small as 0.01%. Irradiance fluctuations are typical of a band-limited noise spectrum with high-frequency cutoff near 0.15/day; their amplitudes about the mean value of 1368.31 watts per square meter approach plus or minus 0.05%. Two large decreases in irradiance of up to 0.2% lasting about one week are highly correlated with the development of sunspot groups. The magnitude and time scale of the irradiance variability suggest that considerable energy storage occurs within the convection zone in solar active regions.

Willson, R. C.↗

NASA NTRS2005

RF Stabilization for Storage of Antiprotons

Portable storage of antimatter is an important step in the experimental exploration of antimatter in propulsion applications. The High Performance Antiproton Trap (HiPAT) at NASA Marshall Space Flight Center is a Penning-Malmberg ion trap being developed to trap and store low energy antiprotons for a period of weeks. The antiprotons can then be transported for use in experiments. HiPAT is being developed and evaluated using normal matter, before an attempt is made to store and transport antiprotons. Stortd ions have inherent instabilities that limit the storage lifetime. RF stabilization at cyclotron resonance frequencies is demonstrated over a period of 6 days for normal matter ion clouds. A variety of particles have been stored, including protons, C+ ions, and H2+ ions. Cyclotron resonance frequencies are defined and experimental evidence presented to demonstrate excitation of cyclotron waves in the plasma for all three species of ions.

Pearson, J. Boise↗

NASA NTRS2024

Power Beaming From Lunar Orbit to Small Lunar Science Assets

Long lunar nights limit science lander lifetimes to only two weeks in most global locations unless they carry large batteries or radioisotopes. An orbiting beamed power spacecraft is another option to provide this energy, thus removing the energy storage burden on the lander while still giving it years of science operations.

Lunar↗

NASA NTRS1985

Application of expert systems in the Common Module electrical power system

Each Common Module (CM) of the Space Station must be capable of handling a 50 kW electricity supply, 25 kW for transmission and 25 kW for consumption. The power must be handled and managed by on-board systems, a necessity that dovetails with the objectives of Public Law 98-371, which mandates that the Space Station push the state of the art of automation and AI. Expert systems will be needed to handle the large data flow for the power system and to ensure that the system degrades gracefully. Features of the first expert systems expected for the power system, i.e., a dynamic load planner/scheduler and energy storage subsystem management, fault diagnosis/analysis, health status/trend analysis, and orbital replacement advisor expert systems, are described. Finally, growth Space Station expert systems applications are discussed.

Weeks, D. J.↗

NASA NTRS2012

Lunar Prospecting Using Thermal Wadis and Compact Rovers: Infrastructure for Surviving the Lunar Night - Part A

Recent missions have confirmed the existence of water and other volatiles on the Moon, both in permanently-shadowed craters and elsewhere. Non-volatile lunar resources may represent significant additional value as infrastructure or manufacturing feedstock. Characterization of lunar resources in terms of abundance concentrations, distribution, and recoverability is limited to in-situ Apollo samples and the expanding remote-sensing database. This paper introduces an approach to lunar resource prospecting supported by a simple lunar surface infrastructure based on the Thermal Wadi concept of thermal energy storage and using compact rovers equipped with appropriate prospecting sensors and demonstration resource extraction capabilities. Thermal Wadis are engineered sources of heat and power based on the storage and retrieval of solar-thermal energy in modified lunar regolith. Because Thermal Wadis keep compact prospecting rovers warm during periods of lunar darkness, the rovers are able to survive months to years on the lunar surface rather than just weeks without being required to carry the burdensome capability to do so. The resulting lower-cost, long-lived rovers represent a potential paradigm breakthrough in extra-terrestrial prospecting productivity and will enable the production of detailed resource maps. Integrating resource processing and other technology demonstrations that are based on the content of the resource maps will inform engineering economic studies that can define the true resource potential of the Moon. Once this resource potential is understood quantitatively, humans might return to the Moon with an economically sound objective including where to go, what to do upon arrival, and what to bring along.

Sacksteder, Kurt R.↗

NASA NTRS2020

On Orbit Flight Testing of the Roll-Out Solar Array

The Roll-Out Solar Array (ROSA) is an innovative, lightweight solar array with a flexible substrate that makes use of the stored strain energy in its composite structural members to provide deployment without the use of motors while still packaging efficiently. The ROSA flight experiment was launched to the International Space Station (ISS)on June 3rd, 2017 as a part of the eleventh SpaceX commercial resupply mission. After two weeks of storage, ROSA was extracted from the Dragon spacecraft, deployed, and put through a week of tests to verify its structural characteristics as well as the performance of photovoltaics. The structural dynamics experiments included active excitation of out-of-plane bending modes, and a study of the thermal-structural interaction of the structure during day-night transitions. Data was gathered from a small number of accelerometers located at key points on the solar array and from cameras observing numerous photogrammetry targets spread out over the structure and the photovoltaic blanket. The goal in this effort was to better understand the performance of ROSA and to improve modeling efforts for future designs of similar solar arrays. Of particular interest are the first few system modes and mode shapes of the array, the amount of structural damping present, and degree of structural-thermal interaction seen during eclipse exit.

ROSA↗

NASA NTRS2004

Ventless pressure control of two-phase propellant tanks in microgravity

This work studies pressurization and pressure control of a large liquid hydrogen storage tank. A finite element model is developed that couples a lumped thermodynamic formulation for the vapor region with a complete solution of the Navier-Stokes and energy equations for the flow and temperature fields in the liquid. Numerical results show that buoyancy effects are strong, even in microgravity, and can reposition a vapor bubble that is initially at the center of the tank to a region near the tank wall in a relatively short time. Long-term tank pressurization with the vapor bubble at the tank wall shows that after an initial transient lasting about a week, the final rate of pressure increase agrees with a purely thermodynamic analysis of the entire tank. However, the final pressure levels are quite different from thermodynamic predictions. Numerical results also show that there is significant thermal stratification in the liquid due to the effects of natural convection. A subcooled jet is used to provide simultaneous cooling and mixing in order to bring the tank pressure back down to its initial value. Three different jet speeds are examined. Although the lowest jet speed is ineffective at controlling the pressure because of insufficient penetration into the liquid region, the highest jet speed is shown to be quite effective at disrupting thermal stratification and reducing the tank pressure in reasonable time.

Weightlessness↗

NASA NTRS1986

A simple biosphere model (SiB) for use within general circulation models

A simple realistic biosphere model for calculating the transfer of energy, mass and momentum between the atmosphere and the vegetated surface of the earth has been developed for use in atmospheric general circulation models. The vegetation in each terrestrial model grid is represented by an upper level, representing the perennial canopy of trees and shrubs, and a lower level, representing the annual cover of grasses and other heraceous species. The vegetation morphology and the physical and physiological properties of the vegetation layers determine such properties as: the reflection, transmission, absorption and emission of direct and diffuse radiation; the infiltration, drainage, and storage of the residual rainfall in the soil; and the control over the stomatal functioning. The model, with prescribed vegetation parameters and soil interactive soil moisture, can be used for prediction of the atmospheric circulation and precipitaion fields for short periods of up to a few weeks.

Sellers, P. J.↗

NASA NTRS2011

Nutrition Research: Basis for Station Requirements

Prior to the Shuttle program, all understanding of nutritional needs in space came from Skylab metabolic research. Because Shuttle flights were short, most less than 14 days, research focused on major nutritional issues: energy (calories), protein and amino acids, water and electrotypes, with some more general physiology studies that related to iron and calcium. Using stable isotope tracer studies and diet intake records, we found that astronauts typically did not consume adequate calories to meet energy expenditure. To monitor energy and nutrient intake status and provide feedback to the flight surgeon and the astronauts, the International Space Station (ISS) program implemented a weekly food frequency questionnaire and routine body mass measurements. Other Shuttle investigations found that protein turnover was higher during flight, suggesting there was increased protein degradation and probably concurrent increase in protein synthesis, and this occurred even in cases of adequate protein and caloric intake. These results may partially explain some of the loss of leg muscle mass. Fluid and electrolyte flight studies demonstrated that water intake, like energy intake, was lower than required. However, sodium intakes were elevated during flight and likely related to other concerns such as calcium turnover and other health-related issues. NASA is making efforts to have tasty foods with much lower salt levels to reduce sodium intake and to promote fluid intake on orbit. Red blood cell studies conducted on the Shuttle found decreased erythrogenesis and increased serum ferritin levels. Given that the diet is high in iron there may be iron storage health concerns, especially related to the role of iron in oxidative damage, complicated by the stress and radiation. The Shuttle nutrition research lead to new monitoring and research on ISS. These data will be valuable for future NASA and commercial crewed missions.

Lane, Helen W.↗

NASA NTRS1972

Relativistic electrons from the sun observed by IMP-4.

Evaluation of data obtained from the IMP-4 satellite concerning 0.3- to 12-MeV electrons from the sun between May 24, 1967, and May 2, 1969. Correlations with contemporary proton intensity increases at energies above 1 MeV are studied. The results of this study are the following: (1) the differential electron energy spectrum (0.3 to 12 keV) from solar flares appears to be a constant of the flare process, with the spectral index gamma = (-) 3.0 plus or minus 0.2; (2) particle emission from solar flares contains a prompt component, which is injected into the interplanetary medium beyond the sun and which is responsible for the diffusion characteristics of solar particle events, and a delayed component which is effectively contained in the lower solar atmosphere where it diffuses typically less than or equal to plus or minus 100 deg in longitude and gradually escapes into interplanetary space; the delayed component gives rise to the corotating features commonly observed after the impulsive and diffusive onset from the prompt component; (3) storage of electrons greater than 300 keV and protons greater than 1 MeV is essential to explain emission and propagation characteristics of solar particle events; and (4) the events with low proton/electron ratios all occur at least three weeks after the previous relativistic electron producing flare.

Simnett, G. M.↗

NASA NTRS2000

Storage Characteristics of Lithium Ion Cells

Lithium ion cells are being developed under the NASA/Air Force Consortium for the upcoming aerospace missions. First among these missions are the Mars 2001 Lander and Mars 2003 Lander and Rover missions. Apart from the usual needs of high specific energy, energy density and long cycle life, a critical performance characteristic for the Mars missions is low temperature performance. The batteries need to perform well at -20 C, with at least 70% of the rated capacity realizable at moderate discharge rates (C/5). Several modifications have been made to the lithium ion chemistry, mainly with respect to the electrolyte, both at JPL' and elsewhere to achieve this. Another key requirement for the battery is its storageability during pre-cruise and cruise periods. For the Mars programs, the cruise period is relatively short, about 12 months, compared to the Outer Planets missions (3-8 years). Yet, the initial results of our storage studies reveal that the cells do sustain noticeable permanent degradation under certain storage conditions, typically of 10% over two months duration at ambient temperatures, attributed to impedance buildup. The build up of the cell impedance or the decay in the cell capacity is affected by various storage parameters, i.e., storage temperature, storage duration, storage mode (open circuit, on buss or cycling at low rates) and state of charge. Our preliminary studies indicate that low storage temperatures and states of charge are preferable. In some cases, we have observed permanent capacity losses of approx. 10% over eight-week storage at 40 C, compared to approx. 0-2% at O C. Also, we are attempting to determine the impact of cell chemistry and design upon the storageability of Li ion cells.

Ratnakumar, B. V.↗

NASA NTRS2000

Power Systems Evaluated for Solar Electric Propulsion Vehicles

Solar electric propulsion (SEP) mission architectures are applicable to a wide range NASA missions including the robotic exploration of the outer planets in the next decade and the human exploration of Mars within the next 2 decades. SEP enables architectures that are very mass efficient with reasonable power levels (1-MW class) aerobrake and cryogenic upper-stage transportation technologies are utilized. In this architecture, the efficient SEP stage transfers the payload from low Earth orbit (LEO) High Energy Elliptical Parking Orbit (HEEPO) within a period of 6 to 12 months. highthrust, cryogenic upper stage and payload then separate from the SEP vehicle for injection to the planetary target, allowing for fast heliocentric trip times. This mission architecture offers a potential reduction in mass to LEO in comparison to alternative all-chemical nuclear propulsion schemes. Mass reductions may allow launch vehicle downsizing enable missions that would have been grounded because of cost constraints. The preceding figure illustrates a conceptual SEP stage design for a human Mars mission. Researchers at the NASA Glenn Research Center at Lewis Field designed conceptual SEP vehicle, conceived the mission architecture to use this vehicle, and analyzed the vehicle s performance. This SEP stage has a dry mass of 35 metric tons (MT), 40 MT of xenon propellant, and a photovoltaic array that spans 110 m, providing power to a cluster of eight 100-kW Hall thrusters. The stage can transfer an 80-MT payload and upper stage to the desired HEEPO. Preliminary packaging studies show this space-station-class SEP vehicle meets the proposed "Magnum" launch vehicle and volume requirements with considerable margin. An SEP vehicle for outer planetary missions, such as the Europa Mapper Mission, would be dramatically smaller than human Mars mission SEP stage. In this mission architecture, the SEP power system with the payload to provide spacecraft power throughout the mission. Several photovoltaic array design concepts were considered for the SEP vehicle power system for the human mission to Mars. These include a space station derivative, a SCARLET (Solar Concentrator Arrays with Refractive Linear Element Technology) derivative, and a hybrid inflatable-deployable thin polymer membrane array with thin-film solar cells (as shown in the concept illustration). This concept is based on a design developed for the Next Generation Space Telescope Sun shield. The array is divided into 16 independent electrical sections with 500-V, negative-grounded solar cell strings. The power system employs a channelized, 500-Vdc power management and distribution (PMAD) architecture with lithium ion batteries for energy storage for vehicle and payload secondary loads (the high-power Hall thrusters do not operate in eclipse periods). The 500-V PMAD voltage permits "direct-drive" thruster operation, greatly reducing the power processing unit size, complexity, and power loss. Similar power system architecture, designs, and technology are assumed for the Europa Mapper Mission SEP vehicle. The primary exceptions are that the photovoltaic array is assumed to consist of two rectangular wings and that the power system rating is 15 kW in Earth orbit and 200 W at Europa. To size the SEP vehicle power system, a dedicated Fortran code was developed to predict detailed power system performance, mass, and thermal control requirements. This code also modeled all the relevant Earth orbit environments; that is, the particulate radiation, plasma, meteoroids and debris, ultraviolet radiation, contamination, and thermal conditions. Analysis results for the Human Mars Mission SEP vehicle show a power system mass of 9-MT and photovoltaic array area of 5800-square meters for the thin-membrane design concept with CuInS2 thin-film cells. Power processing unit input power for a thin-membrane array design with three-junction, amorphous SiGe solar cells is shown in the graph. Power falls off rapidly inhe first weeks of the mission because of light-induced (Staebler-Wronksi) solar cell losses. During the next 200 days, power decreases steadily as the SEP stage spirals through the proton belts and sustains the bulk of the mission radiation damage. Once the vehicle apogee is above approximately four Earth radii, little additional degradation is incurred. From 400 to 800 days, a 1100-km "parking" orbit is maintained to await the next payload transfer opportunity. This orbit is below the main proton belt, and thus, little radiation dose is accumulated during this time period. During the second LEO-to-HEEPO transfer, power degrades somewhat further, but power requirements are still met. In comparison, the Europa Mapper SEP vehicle power system had a mass of 150 kg and a thin membrane array area of 100 square meters.

Kerslake, Thomas W.↗