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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

High-resolution optical measurements of atmospheric winds from space. I - Lower atmosphere molecular absorption

A high-resolution spectroscopic technique, analogous to that used in the thermosphere to measure the vector wind fields in the upper troposphere and stratosphere, is described which uses narrow features in the spectrum of light scattered from the earth's lower atmosphere to provide Doppler information on atmospheric scattering and absorption. It is demonstrated that vector winds can be measured from a satellite throughout the lower atmosphere, using a multiple-etalon Fabry-Perot interferometer of modest aperture. It is found that molecular oxygen and water vapor absorption lines in the spectrum of sunlight scattered by the atmosphere are Doppler-shifted by the line of sight wind, so that they may be used to monitor the global wind systems in the upper troposphere and stratosphere.

Hays, P. B.↗
NASA NTRS1989

A second supernova inside Puppis A?

Narrow-band images of an unusual swirl structure located near the center of the Puppis A supernova remnant are presented which reveal three overlapping filamentary systems of highly diverse composition. One is dominated by emission lines of nitrogen, one by oxygen, and one by sulfur. Spectra indicate that these small rings have high velocities and a corresponding kinematic age of less than 800 yr. Heavy-element abundances are extremely high and different in each system, some reminiscent of knots in Cas A, and others of circumstellar matter observed surrounding supernova 1987A. The youth and unusual chemistry lead to the suggestion that a second supernova has exploded within the shell of Puppis A, giving rise to the swirl structure.

Winkler, P. F.↗
NASA NTRS1992

Airglow and aurora in the atmospheres of Venus and Mars

Measurements and models of the luminosity that originates in the Martian and Venusian atmospheres, including dayglow, nightglow and aurora, are compared. Most of the emission features considered appear in the UV and visible regions of the spectrum and arise from electronic transitions of thermospheric species. Spatially and temporally variable intensities of the oxygen 1304 and 1356 A lines have been observed on the nightside of Venus and have been labeled 'auroral', that is, ascribed to electron precipitation. Only a future aeronomy mission to Mars could unequivocally determine whether such emissions are present on the nightside of Mars.

Fox, J. L.↗
NASA NTRS1992

Options for a lunar base surface architecture

The Planet Surface Systems Office at the NASA Johnson Space Center has participated in an analysis of the Space Exploration Initiative architectures described in the Synthesis Group report. This effort involves a Systems Engineering and Integration effort to define point designs for evolving lunar and Mars bases that support substantial science, exploration, and resource production objectives. The analysis addresses systems-level designs; element requirements and conceptual designs; assessments of precursor and technology needs; and overall programmatics and schedules. This paper focuses on the results of the study of the Space Resource Utilization Architecture. This architecture develops the capability to extract useful materials from the indigenous resources of the Moon and Mars. On the Moon, a substantial infrastructure is emplaced which can support a crew of up to twelve. Two major process lines are developed: one produces oxygen, ceramics, and metals; the other produces hydrogen, helium, and other volatiles. The Moon is also used for a simulation of a Mars mission. Significant science capabilities are established in conjunction with resource development. Exploration includes remote global surveys and piloted sorties of local and regional areas. Science accommodations include planetary science, astronomy, and biomedical research. Greenhouses are established to provide a substantial amount of food needs.

Roberts, Barney B.↗
NASA NTRS1999

Short Duration Base Heating Test Improvements

Significant improvements have been made to a short duration space launch vehicle base heating test technique. This technique was first developed during the 1960's to investigate launch vehicle plume induced convective environments. Recent improvements include the use of coiled nitrogen buffer gas lines upstream of the hydrogen / oxygen propellant charge tubes, fast acting solenoid valves, stand alone gas delivery and data acquisition systems, and an integrated model design code. Technique improvements were successfully demonstrated during a 2.25% scale X-33 base heating test conducted in the NASA/MSFC Nozzle Test Facility in early 1999. Cost savings of approximately an order of magnitude over previous tests were realized due in large part to these improvements.

Bender, Robert L.↗
NASA NTRS2003

Capabilities of the Materials Contamination Team at Marshall Space Flight Center

The Materials Contamination Team at the Marshall Space Flight Center (MSFC) has been recognized for its contributions supporting the National Aeronautics and Space Administration (NASA) spacecraft development programs. These programs include the Reusable Solid Rocket Motor (RSRM), Chandra X-Ray Observatory, and the International Space Station (ISS). The Environmental Effects Group, with the Materials Contamination Team and the Space Environmental Effects Team has been an integral part of NASA's success by the testing, evaluation, and qualification of materials, hardware, and processes. This paper focuses on the capabilities of the Materials Contamination Team. The Materials Contamination Team's realm of responsibility includes establishing contamination control during all phases of hardware development, including design, manufacturing, assembly, test, transportation, launch site processing, on-orbit exposure, return, and refurbishment. The team continues its mission of reducing the risk of equipment failure due to molecular or particulate contamination. Contamination is a concern in the Space Shuttle with sensitive bond-lines and reactive fluid (liquid oxygen) compatibility as well as for spacecraft with sensitive optics, such as Hubble Space Telescope and Chandra X-ray Observatory. The Materials Contamination Team has a variety of facilities and instrumentation capable of contaminant detection, identification, and monitoring. The team addresses material applications dealing with environments, including production facilities, clean rooms, and on-orbit exposure. The optically stimulated electron emission (OSEE) system, the Ultraviolet (UV) fluorescence (UVF) surface contamination detection, and the Surface Optics Corporation 400 (SOC 400) portable hand-held Fourier Transform Infrared (FTIR) spectrometer are state-of-the-art tools for in-process molecular contamination detection. The team of engineers and technicians also develop contamination calibration standards and evaluate new surface cleanliness inspection technologies. The team utilizes facilities for on-orbit simulation testing of materials for outgassing and molecular film deposition characteristics in the presence of space environmental effects, such as Atomic Oxygen (AO) and UV radiation exposure. The Materials Contamination Team maintains databases for process materials as well as outgassing and optical compatibility test results for specific environments.

Burns, Howard↗
NASA NTRS2007

First Terrestrial Soft X-Ray Auroral Observation by the Chandra X-Ray Observatory

Northern auroral regions of Earth were imaged with energetic photons in the 0.1-10keV range using the High-Resolution Camera (HRC-I) aboard the Chandra X-ray Observatory at 10 epochs (each approx.20 min duration) between mid- December 2003 and mid-April 2004. These observations aimed at searching for Earth's soft (< 2 keV) X-ray aurora in a comparative study with Jupiter's X-ray aurora, where a pulsating X-ray "hot-spot" has been previously observed by Chandra. The first Chandra soft X-ray observations of Earth's aurora show that it is highly variable 0ntense arcs, multiple arcs, diffuse patches, at times absent). In at least one of the observations an isolated blob of emission is observed near the expected cusp location. A fortuitous overflight of DMSP satellite F13 provided SSJ/4 energetic particle measurements above a bright arc seen by Chandra on 24 January 2004, 20:01-20:22 UT. A model of the emissions expected strongly suggests that the observed soft X-ray signal is bremsstrahlung and characteristic K-shell line emissions of nitrogen and oxygen in the atmosphere produced by electrons.

Bhardwaj, Anil↗
NASA NTRS1995

The neutral oxygen spectrum. 2: Pumping by hydrogen Lyman-beta under the optically thin condition: A first application to the classical novae

A calculation, employing a detailed model of neutral oxygen, is carried out to give fluorescent line intensities expected in a long-proposed photoexcitation by accidental resonance (PAR) process in which hydrogen Lyman-beta photoexcites the oxygen spectrum. The results pertain to the optically thin case but provide an upper limit to the fluorescent intensities which can be attained. They are applied to analyze line ratios involving the strong 8446 A line observed in classical novae during the diffusion-enhanced and Orion phases. Operation of the PAR process in the novae is verified. It is found that photoexcitation rates in the ejecta reach values greater than 0.1/sec, corresponding to hydrogen Lyman-beta radiation field intensities greater than 1250 ergs/cm/sec/sr.

Kastner, S. O.↗
NASA NTRS2018

The Significance of Slope 1 Variation in Early Solar System Solids

As originally demonstrated by Clayton and co-workers, primitive meteorites and their components commonly display mass-independent oxygen isotopic variation. As a tool to understand this behaviour, a number of reference lines have been defined, with slopes of approximately 1. The Carbonaceous Chondrite Anhydrous Mineral (CCAM) line, derived predominantly from analyses of components in the Allende (CV3) meteorite, is the most widely used reference and has a slope of 0.94 plus or minus 0.01 (2 sigma). However, the fundamental significance of the CCAM line has been questioned. Based on the results of a UV laser ablation study of an Allende CAI (calcium-aluminum–rich inclusion), it was suggested that a line of exactly slope 1 (Y&R line - Young and Russell line) was of more fundamental significance. SIMS (Secondary Ion Mass Spectrometry) analysis of chondrules from primitive CRs and related chondrites define a third, distinct slope 1 line, known as the Primitive Chondrule Minerals (PCM) line. Here we discuss the results of bulk oxygen isotope analysis of CO, CV and CR chondrites and various separated components, with the aim of better understanding the origin of slope 1 behaviour in early Solar System materials.

Greenwood, R. C.↗
NASA NTRS1973

Gettering capsule for removing oxygen from liquid lithium systems

Capsule consisting of tantalum shell lined with tantalum screen and partially filled with lithium and pieces of yttrium is immersed in hot lithium stream. Oxygen is removed from stream by being absorbed by gettering capsule. Oxygen passes through capsule wall and into lithium inside capsule where it reacts with yttrium to form Y2O3.

Tower, L. K.↗
NASA NTRS1982

Silicon and oxygen isotopes in selected Allende inclusions

Silicon and oxygen data are presented for a number of Allende samples. It is found that based on oxygen and silicon isotopes, Allende samples EGG-1, EGG-6, BG1a, and 3529Yc are typical, unfractionated Allende inclusions. Where magnesium data are available, they indicate the same thing. EGG-3 is fractionated in both oxygen and silicon, as it is in magnesium. Sample D7 melilite is fractionated in oxygen by several per mil along the C2-matrix line, away from typical Allende melilites. Inclusion BG10a is a FUN inclusion with an inferred original oxygen isotopic fractionation of 8-9 per mille/amu relative to the Allende line. Silicon data for two density fractions of inclusion 3A with different mineralogies show a difference of about 2 per mille, which indicates that silicon, like oxygen, has been added to at least some mineral phases in Allende inclusions from a reservoir other than the one in which the inclusion first began to form.

Becker, R. H.↗
NASA NTRS1983

Observations of the 145.5 micron O I forbidden emission line in the Orion Nebula

A first set of observations of the forbidden O I 3P0-3P1 (145.5 micron) transition has been obtained. The line was observed both in a 1 x 1 arcmin beam centered on the Trapezium and in a 7 x 7 arcmin beam encompassing most of the Orion Nebula; a wide-beam (7 x 7 arcmin) map of the region has also been constructed which shows that most of the emission is confined to the central regions of the nebula. These observations are consistent with optically thin emission in the 145.5 micron line and self-absorbed 63.2 micron emission lines. Mechanisms for the excitation of neutral oxygen are considered, and it is concluded that much of the observed emission originates in the thin radio recombination line-emitting C II/H I envelope bordering on the H II region.

Stacey, G. J.↗
NASA NTRS2019

Plasma environment effects on K lines of astrophysical interest I. Atomic structure, radiative rates, and Auger widths of oxygen ions

Aims. In the context of black-hole accretion disks, the main goal of the present study is to estimate the plasma environment effects on the atomic structure and radiative parameters associated with the K-vacancy states in ions of the oxygen isonuclear sequence. Methods. We used a time-averaged Debye–Hückel potential for both the electron–nucleus and the electron–electron interactions implemented in the fully relativistic multiconfiguration Dirac–Fock (MCDF) method. Results. Modified ionization potentials, K thresholds, Auger widths, and radiative transition wavelengths and rates are reported for O I–O VII in plasma environments with electron temperature and density ranges 10(exp 5)−10(exp 7) K and 10(exp 18)−10(exp 22)/cu.cm.

J. Deprince↗
NASA NTRS1993

Mars volatile evolution - Implications of the recent measurement of O-17 in water from the SNC meteorites

Escape of oxygen to space on Mars is capable of producing a fractionation of oxygen isotopes in the remaining oxygen which is off of the fractionation line produced by the usual mass-dependent exchange processes. The magnitude of fractionation which can occur can be larger than that which was measured in oxygen in water derived from the SNC meteorites (thought to have come from Mars). In conjunction with the apparent lack of fractionation of O-18 in the atmosphere, this result suggests that less than 25 percent of the oxygen in the Martian climate system has been lost over geologic time. Other mechanisms also might be able to produce such a fractionation, so that this conclusion is not unique; however, it is consistent with other lines of evidence. There is no requirement for an initial volatile inventory with an isotopic composition different from that of the bulk planet (as might be the case for a late veneer of volatile-rich material).

Jakosky, Bruce M.↗
DOE OSTI2023

J1046+4047: an extremely low-metallicity dwarf star-forming galaxy with O32 = 57

ABSTRACT Using the optical spectrum obtained with the Kitt Peak Ohio State Multi-Object Spectrograph mounted on the Apache Point Observatory 3.5 m Telescope and the Sloan Digital Sky Survey spectrum, we study the properties of one of the most metal-poor dwarf star-forming galaxies (SFGs) in the local Universe, J1046+4047. The galaxy, with a redshift z = 0.04874, was selected from the Data Release 16 of the SDSS. Its properties are among the most extreme for SFGs in several ways. The oxygen abundance 12 + log(O/H) = 7.082 ± 0.016 in J1046+4047 is among the lowest ever observed. With an absolute magnitude Mg = −16.51 mag, a low stellar mass M⋆ = 1.8 × 106 M⊙, and a very low mass-to-light ratio M⋆/Lg ∼ 0.0029 (in solar units), J1046+4047 has a very high specific star formation rate sSFR ∼ 430 Gyr−1, indicating very active ongoing star formation. Another striking feature of J1046+4047 is that it possesses a ratio O32 = I([O iii] λ5007)/I([O ii] λ3727) ∼ 57. Using this extremely high O32, we have confirmed and improved the strong-line calibration for the determination of oxygen abundances in the most metal-deficient galaxies, in the range 12 + log(O/H) ≲ 7.65. This improved method is applicable for all galaxies with O32 ≤ 60. We find the H α emission line in J1046+4047 to be enhanced by some non-recombination processes and thus cannot be used for the determination of interstellar extinction.

Izotov, Y. I. (ORCID:0000000214166082)↗
NASA NTRS1978

Microwave radiometer measurement of water vapor path delay: Data reduction techniques

Data reduction techniques are developed to compensate for water vapor path delay, a limiting error source in geodetic measurements made with very long baseline interferometry and in radio ranging to spacecraft. It is shown that water vapor path delay is proportional to a linear combination of saturation-corrected sky brightness temperatures, measured on and off the water vapor line. The effects of emission from liquid water droplets in clouds as well as most of the oxygen emission are removed by the off-line channel. Sky brightness temperatures are saturation-corrected or 'linearized' using estimates of effective sky temperatures made from surface temperature. Tipping curves are used to remove instrumental error. Coefficients are found by two methods: from a regression analysis of measured brightness temperatures versus radiosonde measured delay, and from a regression analysis of theoretical brightness temperatures versus radiosonde measured delay. In each case the coefficients are adjusted for differing climatic conditions by measurements of surface temperature, pressure, and relative humidity. Regression solutions are constrained to remove liquid water contributions and to give the correct slope for radiometer versus radiosonde path delay.

Claflin, E. S.↗
NASA NTRS2012

Analysis of Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption During the ASCENDS 2009-2011 Airborne Campaigns

We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission and have demonstrated the CO2 and O2 measurements from aircraft. Our technique uses two pulsed lasers allowing simultaneous measurement of a single CO2 absorption line near 1572 nm, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are stepped in wavelength across the CO2 line and an O2 line doublet during the measurement. The column densities for the CO2 and O2 are estimated from the differential optical depths (DOD) of the scanned absorption lines via the IPDA technique. For the 2009 ASCENDS campaign we flew the CO2 lidar on a Lear-25 aircraft, and measured the absorption line shapes of the CO2 line using 20 wavelength samples per scan. Measurements were made at stepped altitudes from 3 to 12.6 km over the Lamont OK, central Illinois, North Carolina, and over the Virginia Eastern Shore. Although the received signal energies were weaker than expected for ASCENDS, clear CO2 line shapes were observed at all altitudes. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We averaged every 10 seconds of measurements and used a cross-correlation approach to estimate the range to the scattering surface and the echo pulse energy at each wavelength. We then solved for the best-fit CO2 absorption line shape, and calculated the DOD of the fitted CO2 line, and computed its statistics at the various altitude steps. We compared them to CO2 optical depths calculated from spectroscopy based on HITRAN 2008 and the column number densities calculated from the airborne in-situ readings. The 2009 measurements have been analyzed and they were similar on all flights. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. They showed the expected nearly the linear dependence of DOD vs altitude. The measurements showed ~ 1 ppm random errors for 8-10 km altitudes and ~30 sec averaging times. For the 2010 ASCENDS campaigns we flew the CO2lidar on the NASA DC-8 and added an 02lidar channel. During July 2010 we made measurements of CO2 and O2 column absorption during longer flights over Railroad Valley NV, the Pacific Ocean and over Lamont OK. CO2 measurements were made with 30 steps/scan, 300 scans/sec and improved line resolution and receiver sensitivity. Analysis of the 2010 CO2 measurements shows the expected ~linear change of DOD with altitude. For measurements at altitudes> 6 km the random errors were 0.3 ppm for 80 sec averaging times. For the summer 2011 ASCENDS campaigns we made further improvements to the lidar's CO2 line scan and receiver sensitivity. We demonstrated measurements over the California Central Valley, to stratus cloud tops over the Pacific Ocean, over mountain regions with snow, and over several areas with broken clouds. Details of the lidar measurements and their analysis will be described in the presentation.

Abshire, J. B.↗
NASA NTRS2012

Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption and Range During the ASCENDS 2009-2011 Airborne Campaigns

We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission and have demonstrated the CO2 and O2 measurements from aircraft. Our technique uses two pulsed lasers allowing simultaneous measurement of a single CO2 absorption line near 1572 nm, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are stepped in wavelength across the CO2 line and an O2 line doublet during the measurement. The column densities for the CO2 and O2 are estimated from the differential optical depths (DOD) of the scanned absorption lines via the IPDA technique. For the 2009 ASCENDS campaign we flew the CO2 lidar only on a Lear-25 aircraft, and measured the absorption line shapes of the CO2 line using 20 wavelength samples per scan. Measurements were made at stepped altitudes from 3 to 12.6 km over the Lamont OK, central Illinois, North Carolina, and over the Virginia Eastern Shore. Although the received signal energies were weaker than expected for ASCENDS, clear C02 line shapes were observed at all altitudes. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We averaged every 10 seconds of measurements and used a cross-correlation approach to estimate the range to the scattering surface and the echo pulse energy at each wavelength. We then solved for the best-fit CO2 absorption line shape, and calculated the DOD of the fitted CO2 line, and computed its statistics at the various altitude steps. We compared them to CO2 optical depths calculated from spectroscopy based on HITRAN 2008 and the column number densities calculated from the airborne in-situ readings. The 2009 measurements have been analyzed in detail and they were similar on all flights. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. They showed the expected nearly the linear dependence of DOD vs altitude. The measurements showed -1 ppm random errors for 8-10 km altitudes and -30 sec averaging times. For the 2010 ASCENDS campaigns we flew the CO2 lidar on the NASA DC-8 and added an O2 lidar channel. During July 2010 we made measurements of CO2 and O2 column absorption during longer flights over Railroad Valley NV, the Pacific Ocean and over Lamont OK. CO2 measurements were made with 30 steps/scan, 300 scans/sec and improved line resolution and receiver sensitivity. Analysis of the 2010 CO2 measurements shows the expected -linear change of DOD with altitude. For measurements at altitudes> 6 km the random errors were 0.3 ppm for 80 sec averaging times. For the summer 2011 ASCENDS campaigns we made further improvements to the lidar's CO2 line scan and receiver sensitivity. The seven flights in the 2011 Ascends campaign were flown over a wide variety of surface and cloud conditions in the US, which produced a wide variety of lidar signal conditions. Details of the lidar measurements and their analysis will be described in the presentation.

Abshire, J. B.↗