Trajectories to Comets Using Solar Electric Propulsion
In situ analysis of a cometary nucleus and return of a sample are high priority scientific goals.
trajectory comet low-thrust propulsion↗
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Results for “Solar Analysis”
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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Arcing in Leo and Geo Simulated Environments: Comparative Analysis
Comprehensive tests of two solar array samples in simulated Low Earth Orbit (LEO) and Geosynchronous Orbit (GEO) environments have demonstrated that the arc inception voltage was 2-3 times lower in the LEO plasma than in the GEO vacuum. Arc current pulse wave forms are also essentially different in these environments. Moreover, the wide variations of pulse forms do not allow introducing the definition of a "standard arc wave form" even in GEO conditions. Visual inspection of the samples after testing in a GEO environment revealed considerable damage on coverglass surfaces and interconnects. These harmful consequences can be explained by the discharge energy being one order of magnitude higher in vacuum than in background plasma. The tests also revealed a potential danger of powerful electrostatic discharges that could be initiated on the solar array surface of a satellite in GEO during the ignition of an arcjet thruster.
Vayner, Boris V.↗
Impact of the May 2024 Gannon Storm on Low Earth Orbit Dosimetric Quantities: Comparisons of the NAIRAS Model -Real Time and Re-analysis- with ISS Data
The solar storm of May 2024, the Gannon storm, led to a display of aurora over the globe. One of the less known effects of that storm is on the radiation doses in low-Earth orbit: it first led to a Forbush decrease in dose rates and then to a Solar Energetic Particle (SEP) event that increased the total dose suffered near the international space station. The Nowcast of Aerospace Ionizing RAdiation System (NAIRAS) model predicts dosimetric and radiative flux quantities for assessing human radiation exposure levels and radiation effects on flight electronic systems from the surface of the Earth to deep space. It runs in near-real-time at the CCMC, but also has a run-on-request that allows for a more precise computation thanks to carefully processed data. NAIRAS was able to compute the effects of the Gannon storm at the ISS in real-time and provide ideas of the doses encountered by the astronauts and the experiments in and outside of the station. In this work, we show the simulations of the doses encountered during the storm and compare them with several measurements at the ISS. This work shows the capabilities of NAIRAS to address the problem of the SEP events at low Earth orbit and its real-time capabilities.
Guillaume Gronoff↗
A Techno-Economic Analysis of a 50MWth Light-Trapping Cavity-Planar Solar Receiver Tower Capital Expenditures and its Cost Mitigation Strategies
To maximize thermal efficiency, the National Renewable Energy Laboratory (NREL) has proposed a light-trapping cavity-planar receiver design intended to capture energy from reradiating surfaces. This system implements a macroscale light trapping mechanism induced by panels with triangular channels, this mechanism allows for elevated temperatures on the receiver panels and in turn the temperature of the HTF; using this design coupled with the implementation of a fluidized particle flow as the HTF, it can be expected for some components to reach a peak working temperature of nearly 1000 degrees C cyclically throughout each day-night cycle. While these temperatures correlate to higher efficiency of the CSP tower they also demand intense thermomechanical properties from the materials used to make the receiver panels. In this analysis, we will list our assumptions to provide clarity on the significance of our calculation. This cost analysis will be conducted using a combination of both case study data and surveying industry to determine costs that are relevant to the current market trends. This analysis represents an early attempt to establish the Capital Expenditures required for a CSP tower of such design to determine the feasibility of implementing such a system in the industry.
concentrated solar power (CSP)↗
Spectral Information from Gapped Data. a Comparison of Technique
The fast Fourier transformations (FFT) is used to estimate power spectra of continuous signals evenly sampled on discrete domains. The problem of finding power spectra on unevenly sampled domains, in particular a regularly spaced domain with gaps is discussed. The analysis of the ACRIM solar bolometric intensity data, obtained with a 3/5 on and 2/5 off duty cycle of approximately 100 minutes, would benefit from the techniques. The comparative effectiveness of three different analysis techniques applied to synthetic data generated on gapped domain is reported.
Kuhn, J. R.↗
Selecting Solar. Insights into Residential Photovoltaic (PV) Quote Variation
This analysis leverages available data from EnergySage, an online solar marketplace, to offer the first data-driven characterization of quote variation faced by prospective PV customers, lending early insight into the decisions customers face once they have initial buy-in.
24 POWER TRANSMISSION AND DISTRIBUTION↗
A buck-boost main bus voltage regulator for a solar array battery space power system
Design and operational analysis of buck-boost voltage regulator for solar array battery in space power system
La Vigna, T. A.↗
Degradation of FEP thermal control materials returned from the Hubble Space Telescope
After an initial 3.6 years of space flight, the Hubble Space Telescope was serviced through a joint effort with the NASA and the European Space Agency. Multi-layer insulation (MLI) was retrieved from the electronics boxes of the two magnetic sensing systems (MSS), also called the magnetometers, and from the returned solar array (SA-I) drive arm assembly. The top layer of each MLI assembly is fluorinated ethylene propylene (FEP, a type of Teflon). Dramatic changes in material properties were observed when comparing areas of high solar fluence to areas of low solar fluence. Cross sectional analysis shows atomic oxygen (AO) erosion values up to 25.4 mu m (1 mil). Greater occurrences of through-thickness cracking and surface microcracking were observed in areas of high solar exposure. Atomic force microscopy (AFM) showed increases in surface microhardness measurements with increasing solar exposure. Decreases in FEP tensile strength and elongation were measured when compared to non-flight material. Erosion yield and tensile results are compared with FEP data from the Long Duration Exposure Facility. AO erosion yield data, solar fluence values, contamination, micrometeoroid or debris impact sites, and optical properties are presented.
Zuby, Thomas M.↗
Nature and Variability of Coronal Streamers and their Relationship to the Slow Speed Wind
NASA Grant NAG5-12781 is a study on the "Nature and Variability of Coronal Streamers and their Relationship to the Slow Speed Wind." The two main goals of this study are to identify: 1) Where in the streamer structure does the solar wind originate, and 2) What coronal conditions are responsible for the variability of the slow speed wind. To answer the first question, we examined the mostly closed magnetic field regions in streamer cores to search for evidence of outflow. Preliminary results from the OVI Doppler dimming ratios indicates that most of the flow originates from the edges of coronal streamers but this idea should be confirmed by a comparison of the coronal plasma properties with in situ solar wind data. To answer the second question, the work performed thus far suggests that solar minimum streamers have larger perpendicular velocity distributions than do solar maximum streamers. If it can be shown that solar minimum streamers also produce higher solar wind speeds then this would suggest that streamers and coronal holes have similar solar wind acceleration mechanisms. The key to both questions lie in the analysis of the in situ solar wind data sets. This work was not able to be completed during the period of performance and therefore the grant was formally extended for an additional year at no cost to NASA. We hope to have final results and a publication by the end of the calendar year 2004. The SAO personnel involved in the research are Leonard Strachan (PI), Mari Paz Miralles, Alexander Panasyuk, and a Southern University student Michael Baham.
Strachan, Leonard↗
Preliminary Statistical Maneuver Analysis for A Low-Thrust NRHO to DRO Transfer
To understand practical implications of implementing transfers that leverage multibody dynamics, a statistical analysis is performed on an Earth-Moon Near Rectilinear Halo Orbit (NRHO) to distant retrograde orbit (DRO) transfer using solar electric propulsion. The statistical analysis includes perturbations due to maneu- ver execution and orbit determination error to understand operational character- istics of the transfer such as statistical ∆V and statistical state targeting errors at the final DRO. We explore the need for low-thrust trajectory correction maneuver (TCM) opportunities as well as the delivery accuracy to the final target. Finally, we explore options for long-term-stable target DROs.
low thrust↗
Enabling Dynamic Vehicle Analyses With Improved Atmospheric Attenuation Models in Glenn Research Center Communication Analysis Suite
To aid in meeting the NASA objective of returning humans to the Moon, the Glenn Research Center’s Communication Analysis Suite was augmented with two distinct capabilities. The first capability added was the vehicle propagator. This allows the addition of dynamic aircraft and ground vehicles around any celestial body within the solar system during an analysis. This functionality interpolates the position and velocity of the vehicle relative to a celestial body at the time steps analyzed using the type of path and either a series of waypoints or a direction and duration of travel. The implications of this new capability include lunar rovers and/or drones, such as Dragonfly, where the vehicle propagator will analyze the communications architecture. The newly created vehicle propagator is now in use in communications studies for the 2024 lunar missions, simulating the movement of lunar rovers across the Moon’s southern pole. The second capability added was the augmentation of the atmospheric attenuation model. The previous model did not have a uniform low-elevation attenuation model due to the trigonometric approximation for path length and the exponential nature of low-elevation scintillation. User-defined weather parameters were also added to the updated atmospheric attenuation model. The previous model solely used tabular data based upon the season and location of the transmitting antenna. Multiple simulations of the same configuration now return different results based on the differing weather parameters. Cognitive communications analysis efforts can use this second capability to generate neural network training data based on differing weather conditions at utilized ground stations, a critical step in allowing neural networks to learn how weather parameters impact communications performance.
vehicle propagation↗
Cone and column solar concentrator model Final report
Design feasibility analysis, cone development program, and perprototype optical model construction in cone and column solar energy concentrator development program
CONE↗
Time variability of solar active regions at centimeter wavelengths
An analysis is presented of the variability of centimeter wavelength emission originating from the solar transition region and lower corona, and the variability is compared with the sun's quiescent emission. Sequential dual wavelength observations are presented and used to put constraints on a possible model of the variability of active region emissions and to better understand the dynamics of active regions. It is shown that gyroresonance emission contributes significantly to the active region emission at 6 cm, whereas all the quiet-sun emission can be attributed to free-free emission. From comparison of the quiet-sun and active region models, it is shown that the density at the base of the transition region is higher in active regions.
Shevgaonkar, R. K.↗
How Can NASA Science Benefit Solar Energy Development and Assessment?
This is a keynote presentation for a workshop highlighting the use of remote sensing and modeling products derived with NASA missions and Earth system modeling for solar energy system development. We broadly introduce NASA's fleet of satellite producing publicly available data products that would be useful for the information needed solar energy development. We also introduce the work in Earth system science modeling that provides additional global gridded data products that are also relevant. We identify that one issue is obtaining and using this data is the level of expertise needed to find it. NASA has developed a new Earth Action program to address this gap and bring the data closer to the user. Now under the Energy Resources element, the NASA LaRC's POWER (Prediction of Worldwide Renewable Energy) project has developed a web services platform that provides key information needed for solar energy development as analysis-ready. This means that the data for particular locations are immediately useful for help provide the information needed by engineers and architects to plan for solar systems. Thus, the presentation shows why NASA products would be relevant and then shows examples of finding the needed data through the POWER web portal.
remote sensing↗
Exploring Renewable Energy Opportunities in Select Southeast Asian Countries: A Geospatial Analysis of the Levelized Cost of Energy of Utility-Scale Wind and Solar Photovoltaics
The costs of renewable energy-based electricity generation have fallen precipitously in recent years to levels that are increasingly competitive with traditional generation such as fossil fuel-based generation. As these costs become increasingly competitive, private developers, policymakers, and energy system planners are searching for opportunities to harness high-quality renewable energy resources. Developing economies are setting ambitious targets and exploring how cost-effective, grid-connected renewable energy options can help power economic growth and meet growing electricity demands. This includes the member states of the Association of Southeast Asian Nations (ASEAN) that are determined to reach a target of 23% of renewable energy in the region's total primary energy supply by 2025. A critical gap to identifying opportunities and scaling up renewable energy is the lack of quality data and analyses to support decisions on the investment and deployment of renewables - including wind and solar photovoltaics (PV). This work supports decision making by providing high-quality data and spatial analysis of the cost of utility-scale wind and solar PV generation in select countries of Southeast Asia - specifically, the ASEAN member states. Generation costs are expressed as the levelized cost of energy (LCOE) - a commonly used metric that represents the net present value of the unit cost of electricity during the lifetime of a particular electricity generation technology. This is the first spatial estimate of LCOE for these technologies within the ASEAN member states - providing insights into the roles that renewable energy resource quality and other factors may play in generation costs.
14 SOLAR ENERGY↗
Features of Short-Period Oscillations of Microwave Emission from the Solar Active Region before the Flare
The radiation of microwave sources above sunspots at a frequency of 17 GHz gives information about the parameters of solar plasma in the regions where the magneti-field strength is B ~ 2000 G in the transition region between the chromosphere and corona. Short-period oscillations (with a period of several minutes) of microwave emission from solar active regions (ARs) reflect wave processes in magnetic flux tubes of sunspots. Short-period oscillations of microwave emission from AR NOAA 12242 before two flares on December 17, 2014 are analyzed. This analysis is based on solar radio images obtained by means of the Nobeyama Radio Heliograph with a 10″−15″ two-dimensional spatial resolution. The radio maps of the whole solar disk were synthesized in a nonstandard mode with a cadence of 10 s and an averaging time of 10 s. An increase in the power of about ten-minute oscillations of microwave radiation approximately 40 to 50 min before the M1.5 flare (01: 00 UT) is found. On the same day, an increase in the power of ten-minute oscillations is observed about 60 min before the M8.7 flare (04: 42 UT). This effect is similar to the effect found earlier by two groups of authors independently for three-minute oscillations—namely, they observed a sharp increase in three-minute oscillations 15 to 20 min before the radio burst accompanying the flare. The effect in question may be interpreted as an relationship ofMHD waves propagating along the magnetic flux tube of a sunspot and the onset of the solar flare.
79 ASTRONOMY AND ASTROPHYSICS↗
Sensitivity analysis on optical performance of a novel linear Fresnel concentrating solar power collector
A novel, low-cost linear Fresnel collector for concentrating solar power applications is being developed by Hyperlight Energy (Hyperlight) and the National Renewable Energy Laboratory (NREL). Hyperlight is currently deploying their linear Fresnel collector technology in a half-acre pilot loop near Brawley, California. The optical performance of a concentrating solar power collector represents the largest loss in the efficiency of the overall system. The ability to accurately model the complex optical interactions of a collector becomes essential in successfully implementing a new collector technology. Here, this study presents a detailed sensitivity analysis of the optical performance of Hyperlight linear Fresnel technology, characterizing the effects of potential optomechanical error sources on collector performance. Optical models are implemented in SolTrace, a Monte-Carlo ray-tracing software developed at NREL. First, SolTrace is used to analyze collector sensitivity to individual optomechanical error perturbations in both the primary reflectors and the receiver assembly. Then, a high-fidelity optomechanical error model is adopted to capture the realistic performance of the installed Hyperlight linear Fresnel collector. Finally, the sensitivity analysis can provide insightful guidance to inform the tightening and relaxation of tolerances during manufacturing and implementation of a new collector technology.
14 SOLAR ENERGY↗
Techno-economic analysis of the use of atomic layer deposited transition metal oxides in silicon heterojunction solar cells
The industry for producing silicon solar cells and modules has grown remarkably over the past decades, with more than a 100-fold reduction in price over the past 45?years. The main solar cell fabrication technology has shifted over that time and is currently dominated by the passivated emitter and rear cell (PERC). Other technologies are expected to increase in market share, including tunnel-oxide passivated contact (TOPCon) and heterojunction technology (HJT). In this paper, we examine the cost potential for using atomic layer deposition (ALD) to form transition metal oxide (TMO) layers (MoO x , TiO x and aluminium-doped zinc oxide [AZO]) to use as lower cost alternatives of the p-doped, n-doped and indium tin oxide (ITO) layers, respectively, the layers normally used in HJT solar cells. Using a bottom-up cost and uncertainty model with equipment cost data and process experience in the lab, we find that the production cost of these variations will likely be lower per wafer than standard HJT, with the main cost drivers being the cost of the ALD precursors at high-volume production. We then considered what efficiency is required for these sequences to be cost effective in $/W and discuss whether these targets are technically feasible. This work motivates further work in developing these ALD TMO processes to increase their efficiency towards their theoretical limits to take advantage of the processing cost advantage.
14 SOLAR ENERGY↗