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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

The Impact of Planetary Rotation Rate on the Reflectance and Thermal Emission Spectrum of Terrestrial Exoplanets around Sunlike Stars

Robust atmospheric and radiative transfer modeling will be required to properly interpret reflected-light and thermal emission spectra of terrestrial exoplanets. This will help break observational degeneracies between the numerous atmospheric, planetary, and stellar factors that drive planetary climate. Here, we simulate the climates of earthlike worlds around the Sun with increasingly slow rotation periods, from earthlike to fully Sun-synchronous, using the ROCKE-3D general circulation model. We then provide these results as input to the Spectral Planet Model, which employs the Spectral Mapping Atmospheric Radiative Transfer model to simulate the spectra of a planet as it would be observed from a future space-based telescope. We find that the primary observable effects of slowing planetary rotation rate are the altered cloud distributions, altitudes, and opacities that subsequently drive many changes to the spectra by altering the absorption band depths of biologically relevant gas species(e.g.,HO2,O2, andO3). We also identify a potentially diagnostic feature of synchronously rotating worlds in mid-infraredHO2absorption/emission lines.

Exoplanet atmospheres↗
NASA NTRS1985

A map of the cosmic background radiation at 3 millimeters

Data from a series of balloon flights covering both the Northern and Southern Hemispheres, measuring the large angular scale anisotropy in the cosmic background radiation at 3.3 mm wavelength are presented. The data cover 85 percent of the sky to a limiting sensitivity of 0.7 mK per 7 deg field of view. The data show a 50-sigma (statistical error only) dipole anisotropy with an amplitude of 3.44 + or - 0.17 mK and a direction of alpha = 11.2 h + or - 0.1 h, and delta = -6.0 deg + or - 1.5 deg. A 90 percent confidence level upper limit of 0.00007 is obtained for the rms quadrupole amplitude. Flights separated by 6 months show the motion of earth around the sun. Galactic contamination is very small, with less than 0.1 mK contribution to the dipole quadrupole terms. A map of the sky has been generated from the data.

Lubin, P.↗
NASA NTRS1981

Radiative cryogenic cooler for the near infrared mapping spectrometer for the Galileo Jupiter Orbiter

Summaries of the thermal design, analysis, and testing of a radiative cooler for the Near Infrared Mapping Spectrometer (NIMS) for the Galileo Jupiter Orbiter are presented. The radiative cooler rejects approximately 120 milliwatts of heat at a temperature of 75K when operating in the worst-case thermal environment. The cooler is designed to operate against a relatively hostile thermal environment which varies over 145 deg of instrument scan angle and which includes planetary radiation, solar radiation, and emissions from warm spacecraft surfaces (some of which rotate periodically through the radiator field of view).

Cafferty, T. T.↗
NASA NTRS1971

Climatology of Urban-regional Systems

Urbanized areas have come to be significant if not dominant components of many regional land surfaces. They represent perhaps the most dramatic recent change man has made in his environment - a change that may well burgeon in the foreseeable future as greater percentages of world populations crowd into metropolitan areas. The climate of urban-regional systems is involved because temperature, air, and pollutants added to the air are significant aspects of this change. During the past two years, substantial progress has been made in the application of remote sensing techniques to the study of urban climatology by programs jointly sponsored by NASA and the United States Geological Survey. The initial effort has endeavored with considerable success to map terrestrial radiation emission or the general thermal state of the land surface with the aid of imaging radiometers (mechanical-optical scanners).

Pease, R. W.↗
NASA NTRS1973

July 1973 ground survey of active Central American volcanoes

The author has identified the following significant results. Ground survey has shown that thermal anomalies of various sizes associated with volcanic activity at several Central American volcanoes should be detectable from Skylab. Anomalously hot areas of especially large size (greater than 500 m in diameter) are now found at Santiaguito and Pacaya volcanoes in Guatemala and San Cristobal in Nicaragua. Smaller anomalous areas are to be found at least seven other volcanoes. This report is completed after ground survey of eleven volcanoes and ground-based radiation thermometry mapping at these same points.

Stoiber, R. E.↗
NASA NTRS1973

Discrimination techniques employing both reflective and thermal multispectral signals

Recent improvements in remote sensor technology carry implications for data processing. Multispectral line scanners now exist that can collect data simultaneously and in registration in multiple channels at both reflective and thermal (emissive) wavelengths. Progress in dealing with two resultant recognition processing problems is discussed: (1) More channels mean higher processing costs; to combat these costs, a new and faster procedure for selecting subsets of channels has been developed. (2) Differences between thermal and reflective characteristics influence recognition processing; to illustrate the magnitude of these differences, some explanatory calculations are presented. Also introduced, is a different way to process multispectral scanner data, namely, radiation balance mapping and related procedures. Techniques and potentials are discussed and examples presented.

Malila, W. A.↗
NASA NTRS1974

Near-earth thermal environmental criteria study

A study was made to determine improved values and definitions to be used for thermal environmental design parameters for a spacecraft in near-earth orbit. An algorithm was used to derive a total earth thermal radiation based on a mathematical relationship. Several albedo and earth thermal radiation grid maps were produced on seven track digital magnetic tape. Each map contained the values obtained during a 24 hour period over the entire earth. The output statistics are summarized, and the data processing program is described.

Dash, J. M.↗
NASA NTRS1984

Solar limb brightening at 820 microns

The sun in 820 micron radiation is mapped, and strong radial brightening of the intensity profile is found. The east and west limbs show an intensity excess of about twice that of the quiet north and south limbs. This may be attributable to active regions near the east and west limbs. The radial brightening observed is as strong as that observed by others at 1.3 mm, and much stronger than that observed at 350 microns by still others. A strong general increase in gradual radial brightening with wavelength longward of 350 microns is thus indicated, and this is attributed to variations in the character of chromospheric fine structure above the temperature minimum region.

Lindsey, C.↗
NASA NTRS1989

Active modes of the Pacific ITCZ

ITCZ intensity across the Pacific for the 1975-1976 season is studied. Analysis of the data reveal: zonal bands of convective development; isolated patches of stronger convection; and several zonal bands which merge as tropical intraseasonal oscillations. The ITCZ intensity at 160 deg W is compared with the intensity averaged all the way across the Pacific. Composite outgoing longwave radiation anomaly maps for 22 days of local active ITCZ at 160 deg W, 26 days of zonally averaged active ITCZ, and 16 days of both local and zonal active ITCZ are presented and examined. It is noted that: systematic, yet different, patterns, movement, and temporal behavior correspond to local and zonally extensive convection; intensifying zonal convection moves southward; local convection occurs at two preferential latitudes; and local convection does not mean there is a generally active ITCZ.

Hayes, P. M.↗
NASA NTRS1989

Infrared observations of the Neptunian system

Voyager 2's IR observations of Neptune encompass thermal emissions and broadband radiometer measurements of reflected solar radiation. Temperature maps were obtained for the planet between 80 deg S and 30 deg N for two atmospheric layers, one in the lower stratosphere and the other in the troposphere. The relatively warm pole and equator, with cooler midlatitudes, are qualitatively similar to Uranus, despite the two planets' very different obliquities and internal heat fluxes. Powerful wavelike longitudinal thermal structure is noted, of which some appears to be associated with the Great Dark Spot; a localized cold region uncorrelated with any visible feature is found in the lower stratosphere.

Conrath, B.↗
DOE OSTI2023

INL Soil Contamination Areas - Wildland Fire Radiological Hazards

The largest wildland fire on the INL occurred in 2019 and initiated a reassessment of the hazard of wildfires burning through soil contamination areas. In 2020 during the COVID shutdown, the INL Emergency Management Group and the Radiological Control Group worked together to re-evaluate the hazards from these soil contamination areas that were last evaluated in 2001. The new soil sample data was examined, and the areas were mapped for radiation intensity. A new evaluation of the radiological hazards due to wildfire was completed and issued because of this work. This presentation will describe the work and the methodologies used to complete this re-evaluation.

61 RADIATION PROTECTION AND DOSIMETRY↗
NASA NTRS2003

Mapping the Baby Universe

In June, NASA plans to launch the Microwave Anisotropy Probe (MAP) to survey the ancient radiation in unprecedented detail. MAP will map slight temperature fluctuations within the microwave background that vary by only 0.00001 C across a chilly radiation that now averages 2.73 C above absolute zero. The temperature differences today point back to density differences in the fiery baby universe, in which there was a little more matter here and a little less matter there. Areas of slightly enhanced density had stronger gravity than low-density areas. The high-density areas pulled back on the background radiation, making it appear slightly cooler in those directions.

Wanjek, Christopher↗
DOE OSTI2024

Increased accuracy and signal-to-noise ratio through recent improvements in infra-red video bolometer fabrication and calibration

The infra-red video bolometer (IRVB) is a diagnostic equipped with an infra-red camera that measures the total radiated power in thousands of lines of sight within a large field of view. Recently validated in MAST-U [Fderici et al., Rev. Sci. Instrum. 94, 033502 (2023)], it offers a high spatial resolution map of the radiated power in the divertor region, where large gradients are expected. The IRVB’s sensing element comprises a thin layer of high Z absorbing material, typically platinum, usually coated with carbon to reduce reflections [Peterson et al., Rev. Sci. Instrum. 79, 10E301 (2008)].Here, the possibility of using a relatively inert material such as titanium, is explored that can be produced in layers up to 1 μm compared to 2.5 μm for Pt and then coat it with Pt of the desired thickness (0.3 μm per side here) and carbon. This leads to a higher temperature signal (about 3 times) and better spatial resolution (about 4 times), resulting in higher accuracy in the measured power [Peterson et al., Rev. Sci. Instrum. 79, 10E301 (2008)]. This assembly is also expected to improve foil uniformity, as the Pt layer is obtained via deposition rather than mechanical processes [Mukai et al., Rev. Sci. Instrum. 87, 2014 (2016)].Given its multi-material composition, measuring the thermal properties of the foil assembly is vital. Various methods using a calibrated laser as a heat source have been developed, analyzing the temperature profile shape [Sano et al., Plasma and Fusion Res. 7, 2405039 (2012)] and [Mukai et al., Rev. Sci. Instrum. 89, 10E114 (2018)] or fitting the calculated laser power for different intensities and frequencies [Fderici et al., Rev. Sci. Instrum. 94, 033502 (2023)]. Here, a simpler approach is presented, which relies on analyzing the separate components of the foil heat equation for a single laser exposure in a given area. This can then be iterated over the entire foil to capture local deviations.

Magnetic Fusion Energy↗
NASA NTRS1979

The spectral and spatial distribution of radiation from Eta Carinae. II High-resolution infrared maps of the Homunculus

The spectral and spatial distribution of radiation from Eta Carinae II and high-resolution infrared maps of the Homunculus are presented. It is found that at the resolution of 1.1 arcsec the source is resolved into two intensity peaks at four wavelengths from 3.6 to 11.2 microns. The separation of the two peaks with wavelength is discussed, concluding that they are produced by an asymmetrical distribution of dust formed by extensive mass loss from the central source. The extension of the wings of the source at various wavelengths provide confirmatory evidence for an enrichment of a grain species such as corundum, relative to silicate material in the outer regions of the source.

Hyland, A. R.↗