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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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At least 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Estudio de Resiliencia de la Red Electrica de Puerto Rico y Transiciones a Energia 100% Renovable (PR100): Actualizacion de Progreso de Seis Meses [Slides]

Puerto Rico se ha comprometido a satisfacer sus necesidades de electricidad con un 100% de energia renovable para 2050, junto con el cumplimiento de objetivos intermedios del 40% para 2025, el 60% para 2040, la eliminacion gradual de la generacion a base de carbon para 2028, y una mejora del 30% en la eficiencia energetica para 2040, segun lo establecido en la Ley de Politica Publica Energetica de Puerto Rico (Ley 17). Desde los huracanes Irma y Maria en septiembre de 2017, DOE y sus laboratorios nacionales han proporcionado a las partes interesadas del sistema energetico de Puerto Rico herramientas, adiestramiento y apoyo de modelaje para permitir la planificacion y el funcionamiento de la red electrica con mas resiliencia frente a nuevas interrupciones. El 2 de febrero de 2022, DOE, FEMA y seis laboratorios nacionales lanzaron el Estudio de Resiliencia de la Red Electrica de Puerto Rico y Transicion a la Energia 100% Renovable (PR100), de dos anos de duracion, para llevar a cabo un analisis exhaustivo de las vias impulsadas por las partes interesadas para el futuro energetico de Puerto Rico. El analisis energetico, solido y objetivo, comprende cinco actividades, con enfasis en la confiabilidad del sistema electrico, la resiliencia y la planificacion de la generacion. Esta presentacion se realizo en un seminario web publico el 21 de julio del 2022, proporcionando un resumen general del progreso en los primeros seis meses del Estudio, incluyendo la presentacion de cuatro escenarios iniciales definidos mediante un rol activo de las partes interesadas. This is the Spanish translation of NREL/PR-6A20-83431.

14 SOLAR ENERGY↗
DOE OSTI2022

Estudio de Resiliencia de la Red Electrica de Puerto Rico y Transicion a Energia 100% Renovable (PR100): Actualizacion de Progreso de Seis Meses [Slides]

Puerto Rico se ha comprometido a satisfacer sus necesidades de electricidad con un 100% de energia renovable para 2050, junto con el cumplimiento de objetivos intermedios del 40% para 2025, el 60% para 2040, la eliminacion gradual de la generacion a base de carbon para 2028, y una mejora del 30% en la eficiencia energetica para 2040, segun lo establecido en la Ley de Politica Publica Energetica de Puerto Rico (Ley 17). Desde los huracanes Irma y Maria en septiembre de 2017, DOE y sus laboratorios nacionales han proporcionado a las partes interesadas del sistema energetico de Puerto Rico herramientas, adiestramiento y apoyo de modelaje para permitir la planificacion y el funcionamiento de la red electrica con mas resiliencia frente a nuevas interrupciones. El 2 de febrero de 2022, DOE, FEMA y seis laboratorios nacionales lanzaron el Estudio de Resiliencia de la Red Electrica de Puerto Rico y Transicion a la Energia 100% Renovable (PR100), de dos anos de duracion, para llevar a cabo un analisis exhaustivo de las vias impulsadas por las partes interesadas para el futuro energetico de Puerto Rico. El analisis energetico, solido y objetivo, comprende cinco actividades, con enfasis en la confiabilidad del sistema electrico, la resiliencia y la planificacion de la generacion. Esta presentacion provee una actualizacion de progreso del trabajo de seis meses sobre el Estudio, incluyendo la presentacion de cuatro escenarios iniciales definidos mediante un rol activo de las partes interesadas. This is the Spanish translation of NREL/PR-6A20-83432.

14 SOLAR ENERGY↗
NASA NTRS1966

Probability of solar flare occurrences.

Solar flare occurrences probability, designating two-year period centered on sunspot minimum as safe time zone for vehicles on missions to Mars and Venus

SUNSPOT CYCLE↗
NASA NTRS1975

Heavy cosmic-ray exposure of Apollo astronauts

A comprehensive study of the heavy-particle cosmic-ray exposure received by the individual astronauts during the nine lunar Apollo missions reveals a significant variation in the exposure as a function of shielding and the phase of the solar cycle. The data are useful in planning for future long-range missions and in estimating the expected biological damage.

Benton, E. V.↗
NASA NTRS1976

The plasmapause revisited

Saturation of the dc double probe instrument on Explorer 45 was used to identify the plasmapause. A data base was developed to statistically study the average position of the plasmapause over 14.5 hours of magnetic local time under differing magnetic conditions. The afternoon-evening bulge in the L coordinate of the plasmapause versus local time was found centered between 20 and 21 hours MLT during magnetically quiet periods and shifted toward dusk as activity increased, but always post dusk. During quiet periods a bulge in the L coordinate near noon was also seen, which disappeared as activity increased. The average local time distribution plasmapause position during high magnetic activity was irregular in the afternoon region where large scale convection models predict the creation of plasmatails or detached plasma regions from increases in the solar wind induced convection. The results suggest that solar wind induced convection is partially shielded from the dayside. As the intensity of the convection is increased, it more effectively penetrates the dayside, which shifts the post dusk bulge nearer to dusk and eliminates the quiet-time bulge near noon.

Maynard, N. C.↗
NASA NTRS1975

Minimum thrust levels for spinning drag-free satellites

A drag-free satellite, which contains an internal unsupported proof mass, is shielded from external forces such as solar pressure. Thrustors force the satellite to follow the proof mass and hence the satellite follows an almost purely gravitational orbit. The dominant internal disturbing force is the mass attraction of the satellite on the proof mass. Spinning the satellite reduces this force and it has been investigated what the size of the thrustors must be in this case. This size is much smaller than originally thought. Its impact on some other features is shown.

Olsder, G. J.↗
NASA NTRS1991

Biospheric-atmospheric coupling on the early Earth

Theoretical calculations performed with a one-dimensional photochemical model have been performed to assess the biospheric-atmospheric transfer of gases. Ozone reached levels to shield the Earth from biologically lethal solar ultraviolet radiation (220-300 nm) when atmospheric oxygen reached about 1/10 of its present atmospheric level. In the present atmosphere, about 90 percent of atmospheric nitrous oxide is destroyed via solar photolysis in the stratosphere with about 10 percent destroyed via reaction with excited oxygen atoms. The reaction between nitrous oxide and excited oxygen atoms leads to the production of nitric oxide in the stratosphere, which is responsible for about 70 percent of the global destruction of oxygen in the stratosphere. In the oxygen/ozone deficient atmosphere, solar photolysis destroyed about 100 percent of the atmospheric nitrous oxide, relegating the production of nitric oxide via reaction with excited oxygen to zero. Our laboratory and field measurements indicate that atmospheric oxygen promotes the biogenic production of N2O and NO via denitrification and the biogenic production of methane by methanogenesis.

Levine, J. S.↗
NASA NTRS1993

Radiation model predictions and validation using LDEF satellite data

Predictions and comparisons with the radiation dose measurements on Long Duration Exposure Facility (LDEF) by thermoluminescent dosimeters were made to evaluate the accuracy of models currently used in defining the ionizing radiation environment for low Earth orbit missions. The calculations include a detailed simulation of the radiation exposure (altitude and solar cycle variations, directional dependence) and shielding effects (three-dimensional LDEF geometry model) so that differences in the predicted and observed doses can be attributed to environment model uncertainties. The LDEF dose data are utilized to assess the accuracy of models describing the trapped proton flux, the trapped proton directionality, and the trapped electron flux.

Armstrong, T. W.↗
NASA NTRS1994

Lean spacecraft avionics trade study

Spacecraft design is generally an exercise in design trade-offs: fuel vs. weight, power vs. solar cell area, radiation exposure vs. shield weight, etc. Proper analysis of these trades is critical in the development of lightweight, efficient, 'lean' satellites. The modification of the launch plans for the Magnetosphere Imager (MI) to a Taurus launcher from the much more powerful Delta has forced a reduction in spacecraft weight availability into the mission orbit from 1300 kg to less than 500 kg. With weight now a driving factor it is imperative that the satellite design be extremely efficient and lean. The accuracy of engineering trades now takes on an added importance. An understanding of spacecraft subsystem interactions is critical in the development of a good spacecraft design, yet it is a challenge to define these interactions while the design is immature. This is currently an issue in the development of the preliminary design of the MI. The interaction and interfaces between this spacecraft and the instruments it carries are currently unclear since the mission instruments are still under development. It is imperative, however, to define these interfaces so that avionics requirements ideally suited to the mission's needs can be determined.

Main, John A.↗
NASA NTRS1995

Modeling the Earth's magnetospheric magnetic field confined within a realistic magnetopause

Empirical data-based models of the magnetosphereic magnetic field have been widely used during recent years. However, the existing models (Tsyganenko, 1987, 1989a) have three serious deficiencies: (1) an unstable de facto magnetopause, (2) a crude parametrization by the K(sub p) index, and (3) inaccuracies in the equatorial magnetotail B(sub z) values. This paper describes a new approach to the problem; the essential new features are (1) a realistic shape and size of the magnetopause, based on fits to a large number of observed crossing (allowing a parametrization by the solar wind pressure), (2) fully controlled shielding of the magnetic field produced by all magnetospheric current systems, (3) new flexible representations for the tail and ring currents, and (4) a new directional criterion for fitting the model field to spacecraft data, providing improved accuracy for field line mapping. Results are presented from initial efforts to create models assembled from these modules and calibrated against spacecraft data sets.

Tsyganenko, N. A.↗
NASA NTRS2003

Dot-Projection Photogrammetry and Videogrammetry of Gossamer Space Structures

This paper documents the technique of using hundreds or thousands of projected dots of light as targets for photogrammetry and videogrammetry of gossamer space structures. Photogrammetry calculates the three-dimensional coordinates of each target on the structure, and videogrammetry tracks the coordinates versus time. Gossamer structures characteristically contain large areas of delicate, thin-film membranes. Examples include solar sails, large antennas, inflatable solar arrays, solar power concentrators and transmitters, sun shields, and planetary balloons and habitats. Using projected-dot targets avoids the unwanted mass, stiffness, and installation costs of traditional retroreflective adhesive targets. Four laboratory applications are covered that demonstrate the practical effectiveness of white-light dot projection for both static-shape and dynamic measurement of reflective and diffuse surfaces, respectively. Comparisons are made between dot-projection videogrammetry and traditional laser vibrometry for membrane vibration measurements. The paper closes by introducing a promising extension of existing techniques using a novel laser-induced fluorescence approach.

Pappa, Richard S.↗
NASA NTRS2003

Offset of a Drag-Free Sensor from the Center of Gravity of Its Satellite

The drag-free satellite is one that encloses a proof mass, shielding it from atmospheric drag and solar radiation pressure (SRP). By sensing the location of the proof mass in the body and using thrusters to force the spacecraft to follow the proof mass in a closed-loop fashion, the effects of drag and SRP may be eliminated from the spacecraft orbit. Thus, several benefits may be gained, including improved ephemeris propagation and reduced operational costs. The package including the proof mass and the location sensing equipment may be considered as a single sensor; if generalized, such a sensor could be manufactured and used more easily in satellite designs, similar to how current missions use, for example, rate gyros and magnetometers. The flight heritage of the technology has been such that the proof mass sensor is a primary facet of the mission, allowing it to dominate design considerations. In particular, this paper discusses the effects that may be expected if a generalized drag-free sensor is placed some distance away from the spacecraft center of gravity. The proof mass will follow a given gravitational orbit, and a separation from the spacecraft center of gravity places the spacecraft itself in a different orbit from the proof mass, requiring additional fuel just to maintain function of the drag- free sensor. Conclusions include some guiding principles for determining whether certain mission characteristics may restrict or preclude the use of drag-free sensors for that mission. These principles may be used both by mission planners considering drag-free missions and by hardware designers considering or pursuing the development of such generalized sensors.

Starin, Scott R.↗
NASA NTRS2004

Narrow Scale Flow and a Weak Field by the Top of Earth's Core: Evidence from Orsted, Magsat and Secular Variation

As Earth's main magnetic field weakens, our magnetic shield against the onslaught of the solar wind thins. And the field strength needed to fend off battering by solar coronal mass ejections is decreasing, just when the delicate complexity of modem, vulnerable, electro-technological systems is increasing at an unprecedented rate. Recently, a working group of distinguished scientist from across the nation has asked NASA's Solid Earth and Natural Hazards program a key question: What are the dynamics of Earth s magnetic field and its interactions with the Earth system? Paleomagnetic studies of crustal rocks magnetized in the geologic past reveal that polarity reversals have occurred many times during Earth s history. Networked super-computer simulations of core field and flow, including effects of gravitational, pressure, rotational Coriolis, magnetic and viscous forces, suggest how this might happen in detail. And space-based measurements of the real, time-varying magnetic field help constrain estimates of the speed and direction of fluid iron flowing near the top of the core and enable tests of some hypotheses about such flow. Now scientists at NASA s Goddard Space Flight Center have developed and applied methods to test the hypotheses of narrow scale flow and of a dynamically weak magnetic field near the top of Earth s core. Using two completely different methods, C. V. Voorhies has shown these hypotheses lead to specific theoretical forms for the "spectrum" of Earth s main magnetic field and the spectrum of its rate of change. Much as solar physicists use a prism to separate sunlight into its spectrum, from long wavelength red to short wavelength blue light, geophysicists use a digital prism, spherical harmonic analysis, to separate the measured geomagnetic field into its spectrum, from long to short wavelength fields. They do this for the rate of change of the field as well.

Voorhies, Coerte V.↗
NASA NTRS2011

Signal Processing for a Lunar Array: Minimizing Power Consumption

Motivation for the study is: (1) Lunar Radio Array for low frequency, high redshift Dark Ages/Epoch of Reionization observations (z =6-50, f=30-200 MHz) (2) High precision cosmological measurements of 21 cm H I line fluctuations (3) Probe universe before first star formation and provide information about the Intergalactic Medium and evolution of large scale structures (5) Does the current cosmological model accurately describe the Universe before reionization? Lunar Radio Array is for (1) Radio interferometer based on the far side of the moon (1a) Necessary for precision measurements, (1b) Shielding from earth-based and solar RFI (12) No permanent ionosphere, (2) Minimum collecting area of approximately 1 square km and brightness sensitivity 10 mK (3)Several technologies must be developed before deployment The power needed to process signals from a large array of nonsteerable elements is not prohibitive, even for the Moon, and even in current technology. Two different concepts have been proposed: (1) Dark Ages Radio Interferometer (DALI) (2)( Lunar Array for Radio Cosmology (LARC)

Fourier Transform Spectrometer↗