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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 1,585 records · Page 88
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Evolution of Ca-Al-rich bodies in the earliest solar system Growth by incorporation

Thirty different Allende Ca-Al-rich inclusions (CAIs), 11 of type A and 19 of type B, were examined for spinel palisades and framboids, and the possible origins of these structures are discussed. Possible mechanisms for in situ formation of palisades are assessed, all of them either being rejected outright or considered highly implausible. The evidence for external formation and incorporation of palisade bodies is then assessed, and possible mechanisms are considered. It is proposed that type B CAIs are residues from the heating and incomplete evaporation of interstellar dust during the accretion of the protosolar nebula, and that type A CAIs are later condensates from completely evaporated dust whose exotic O-16-rich component became more diluted in the gas phase.

Wark, D. A.↗
NASA NTRS1986

Cloud-to-ground lightning activity in mesoscale convective complexes

An analysis of the evolution of cloud-to-ground lightning discharges attending convective storms in mesoscale convective systems was conducted in the framework of the mesoscale convective complexes (MCCs) life cycle. The lightning discharge data were acquired by a commercially available lightning detection and location system. Peak rates averaged 42/min for the MCCs analyzed; these rates are comparable to the highest observed rates within other mesoscale storm systems and are greater than 20 times the rates previously observed in isolated thunderstorms. Lightning damage occurs with half of the MCCs and is most frequent between the development and the mature phases of the MCC life cycle. The most active period is also characterized by the greatest average number of discrete strokes and largest fraction of multiple-stroke discharges. The total cloud-to-ground lightning activity and maximum flashing rate do not appear to be directly related to either the size of the cloud shield or total duration of the MCC.

Goodman, S. J.↗
NASA NTRS2011

Galex and Optical Observations of GW Librae during the Long Decline from Superoutburst

The prototype of accreting, pulsating white dwarfs (GW Lib) underwent a large amplitude dwarf nova outburst in 2007. We used ultraviolet data from Galaxy Evolution Explorer and ground-based optical photometry and spectroscopy to follow GW Lib for three years following this outburst. Several variations are apparent during this interval. The optical shows a superhump modulation in the months following outburst, while a 19 minute quasi-periodic modulation lasting for several months is apparent in the year after outburst. A long timescale (about 4 hr) modulation first appears in the UV a year after outburst and increases in amplitude in the following years. This variation also appears in the optical two years after outburst but is not in phase with the UV. The pre-outburst pulsations are not yet visible after three years, likely indicating the white dwarf has not returned to its quiescent state.

NOVAE↗
NASA NTRS2017

Detection of DNA Damage by Space Radiation in Human Fibroblasts Flown on the International Space Station

Space radiation consists of energetic charged particles of varying charges and energies. Exposure of astronauts to space radiation on future long duration missions to Mars, or missions back to the Moon, is expected to result in deleterious consequences such as cancer and comprised central nervous system (CNS) functions. Space radiation can also cause mutation in microorganisms, and potentially influence the evolution of life in space. Measurement of the space radiation environment has been conducted since the very beginning of the space program. Compared to the quantification of the space radiation environment using physical detectors, reports on the direct measurement of biological consequences of space radiation exposure have been limited, due primarily to the low dose and low dose rate nature of the environment. Most of the biological assays fail to detect the radiation effects at acute doses that are lower than 5 centiSieverts. In a recent study, we flew cultured confluent human fibroblasts in mostly G1 phase of the cell cycle to the International Space Station (ISS). The cells were fixed in space after arriving on the ISS for 3 and 14 days, respectively. The fixed cells were later returned to the ground and subsequently stained with the gamma-H2AX (Histone family, member X) antibody that are commonly used as a marker for DNA damage, particularly DNA double strand breaks, induced by both low-and high-linear energy transfer radiation. In our present study, the gamma-H2AX (Histone family, member X) foci were captured with a laser confocal microscope. To confirm that some large track-like foci were from space radiation exposure, we also exposed, on the ground, the same type of cells to both low-and high-linear energy transfer protons, and high-linear energy transfer Fe ions. In addition, we exposed the cells to low dose rate gamma rays, in order to rule out the possibility that the large track-like foci can be induced by chronic low-linear energy transfer radiation.

Lu, Tao↗
NASA NTRSDate not supplied

TPSAS-NF1676L-17800-DND

Currently, there are two national challenge problems that guide much of the research in durability and damage tolerance at NASA Langley. The first, Airframe Digital Twin, is a concept that combines as-built vehicle components, as-experienced loads and environments, and other vehicle-specific characteristics to enable ultrahigh fidelity modeling of aircraft and spacecraft throughout their service lives. The second, Materials Genome Initiative, is an analog to the Human Genome Project, and is intended to improve the rate at which materials scientists can discover, understand fundamental physics, and improve material systems. This presentation will highlight several research projects ongoing at NASA Langley that are in support of the above challenge problems. Two of those topics will be the subject of detailed discussion. First, investigations of microstructurally-small fatigue cracking (MSFC) in Al-2Cu and Al-4Cu, fabricated in-house, will be presented. Single- and oligo-crystals of Al-Cu specimens were loaded in uniaxial fatigue, while high-resolution in-situ measurements of deformation were made using image correlation (IC) in a scanning-electron microscope (SEM). The Al-Cu specimens were then replicated as crystal plasticity finite element models (CPFEM), where evolution of slip localization near grain boundaries was computed. Comparison among experiment and CPFEM is made. In addition, XRay diffraction measurements of the as-fabricated specimens were carried out, where direct measurements of the embedded copper precipitates were made, and their influence on growing MSFCs were directly observed. The second main topic will illustrate ongoing work in the area of so-called damage-sensing particles. In this work, shape-memory alloys are embedded in an aluminum alloy matrix. Upon the propagation of a fatigue crack, these particles undergo a strain-induced phase transformation which is detected using an acoustic sensor, providing real-time information on propagating cracks. Experiments and simulations regarding the development of this system will also be detailed.

Jacob Hochhalter↗
NASA NTRS2005

NASA Strategic Roadmap: Origin, Evolution, Structure, and Destiny of the Universe

The NASA strategic roadmap on the Origin, Evolution, Structure and Destiny of the Universe is one of 13 roadmaps that outline NASA s approach to implement the vision for space exploration. The roadmap outlines a program to address the questions: What powered the Big Bang? What happens close to a Black Hole? What is Dark Energy? How did the infant universe grow into the galaxies, stars and planets, and set the stage for life? The roadmap builds upon the currently operating and successful missions such as HST, Chandra and Spitzer. The program contains two elements, Beyond Einstein and Pathways to Life, performed in three phases (2005-2015, 2015-2025 and >2025) with priorities set by inputs received from reviews undertaken by the National Academy of Sciences and technology readiness. The program includes the following missions: 2005-2015 GLAST, JWST and LISA; 2015-2025 Constellation-X and a series of Einstein Probes; and >2025 a number of ambitious vision missions which will be prioritized by results from the previous two phases.

White, Nicholas E.↗
NASA NTRS1981

Spectral evolution of the 5 March 1979 gamma burst

The spectral development of the intense gamma-ray burst observed on March 5, 1979 by nine spacecraft spaced on an interplanetary scale is discussed. As observed by the Pioneer Venus Orbiter detector, the hardness ratio of the burst, defined as the ratio between counts in the 100-1000 keV channels to those in the 50-100 keV channel, decreases during the very fast rise and subsequent 75 msec of the burst, consistent with a decrease in black-body temperature from 30 to 26 keV, and then increases during the shoulder on the gamma-ray burst light curve. Following the burst, the source was observed to exhibit many of the characteristics of a hard X-ray pulsar with a period of 8.0 sec and a hardness ratio varying in phase with the intensity. The observed characteristics of the pulsations are interpreted in terms of hot spots at the magnetic poles of a rotating neutron star, although it is shown that the simple cooling of residual hot spots does not completely explain the pulsations. Alternative explanations for the pulsation include accretion or an effect of beam geometry.

Fenimore, E. E.↗
NASA NTRS1985

Space station propulsion requirements study

Propulsion system requirements to support Low Earth Orbit (LEO) manned space station development and evolution over a wide range of potential capabilities and for a variety of STS servicing and space station operating strategies are described. The term space station and the overall space station configuration refers, for the purpose of this report, to a group of potential LEO spacecraft that support the overall space station mission. The group consisted of the central space station at 28.5 deg or 90 deg inclinations, unmanned free-flying spacecraft that are both tethered and untethered, a short-range servicing vehicle, and a longer range servicing vehicle capable of GEO payload transfer. The time phasing for preferred propulsion technology approaches is also investigated, as well as the high-leverage, state-of-the-art advancements needed, and the qualitative and quantitative benefits of these advancements on STS/space station operations. The time frame of propulsion technologies applicable to this study is the early 1990's to approximately the year 2000.

Wilkinson, C. L.↗
NASA NTRS1993

PG 0308 + 096 and PG 1026 + 002 - Two new short period binary stars resulting from common-envelope evolution

Ultraviolet spectroscopy, optical spectroscopy, and spectrophotometry have been used to study the excess UV stars PG 0308 + 096 and PG 1026 + 002. Both objects are short-period binary systems, each containing a DA white dwarf star and a dM star. Orbital periods of approximately 0.284 day for PG 0308 + 096, and aproximately 0.597 day for PG 1026, have been found by spectroscopic analysis of the H-alpha emission line. Ly-alpha and Balmer line profile fitting were used to estimate the mass of white dwarf stars; mass estimates for the dM stars are based on their spectral types. The orbital inclinations are derived from these masses, the periods, and amplitudes of the H-alpha radial velocity curves. The equivalent width of the H-alpha emission line, in each binary system, varies with the orbital phase in such a manner as to imply that it arises, in large part at least, from the hemisphere of the M star that faces the white dwarf star.

Saffer, Rex A.↗
NASA NTRS2010

Space Shuttle Main Engine (SSME) Systems Operation Overview and Evolution

The Space Shuttle Main Engine (SSME) is a large thrust class, reusable, staged combustion cycle rocket engine employing liquid hydrogen and liquid oxygen propellants. A cluster of three SSMEs is used on every space shuttle mission to propel the space shuttle orbiter vehicle into low earth orbit. Development of the SSME began in the early 70's and the first flight of the space shuttle occurred in 1981. Today, the SSME has accrued over one million seconds of ground test and flight operational time, launching 129 space shuttle missions. The systems operation of the SSME was developed and evolved to support the specific requirements of the Space Shuttle Program (SSP). This paper provides a systems operation overview of the SSME, including: engine cycle, propellant flowpaths, and major components; control system; operations during pre-start, start, mainstage, and shutdown phases; launch commit criteria (LCCs) and operational redlines. Furthermore, this paper will discuss how changes to the SSME over its history have impacted systems operations.

Benefield, Philip A.↗
NASA NTRS2022

Effect of the Heliospheric State on CME Evolution

The culmination of solar cycle 24 by the end of 2019 has created the opportunity to compare the differing properties of coronal mass ejections (CMEs) between two whole solar cycles: solar cycle 23 (SC 23) and solar cycle 24 (SC 24). We report on the width evolution of limb CMEs in SCs 23 and 24 in order to test the suggestion by Gopalswamy et al. that CME flux ropes attain pressure balance at larger heliocentric distances in SC 24. We measure CME width as a function of heliocentric distance for a significantly large number of limb CMEs (∼1000) and determine the distances where the CMEs reach constant width in each cycle. We introduced a new parameter, the transition height (hc) of a CME, defined as the critical heliocentric distance beyond which the CME width stabilizes to a quasi-constant value. Cycle and phase-to-phase comparisons are based on this new parameter. We find that the average value of hc in SC 24 is 62% higher than that in SC 23. SC 24 CMEs attain their peak width at larger distances from the Sun than SC 23 CMEs do. The enhanced transition height in SC 24 is new observational ratification of the anomalous expansion. The anomalous expansion of SC 24 CMEs, which is caused by the weak state of the heliosphere, accounts for the larger heliocentric distance where the pressure balance between CME flux rope and the ambient medium is attained.

Solar coronal mass ejections↗
NASA NTRS1994

The early bolometric evolution of Nova Cygni 1992

We report on combined ultraviolet and optical observations of early stages of the outburst of Nova Cygni 1992. We show that the initial optical rise and decline were produced by the dramatic increase in UV line opacity and its gradual subsequent lifting as the ejecta expand. The source of the M(sub v) - t(sub 3) relation is easily understood in light of these low-resolution UV spectra. The multiwavelength data confirm the theoretical prediction that a nova evolves at a constant bolometric luminosity in the early stages of outburst. We verify the prediction for this nova for at least the first month of the outburst. The detection of far-UV radiation with the Voyager Ultraviolet Spectrometer and the detection of an increasing X-ray flux with Roentgen Satellite (ROSAT) imply that this phase lasted for more than 6 months.

Shore, Steven N.↗
NASA NTRS1982

A spectral energetics analysis of atmospheric blocking

The spectral energetics of two blocking case studies from the winter of 1978-79 are calculated. One case occurred over the North Atlantic and the other over the North Pacific. The temporal evolution and geographical distribution of the energetics of the planetary-scale (zonal harmonic wavenumbers 1-4) and the intermediate-scale (wavenumbers 5-10) wave ensembles are examined to identify the physical mechanisms important in the blocking process. The Atlantic block was forced by the nonlinear interaction of intense baroclinic cyclone-scale waves with barotropic, ultralong waves. The Pacific blocking resulted from the baroclinic amplification of planetary-scale waves. In addition, at least two necessary conditions are required for the development of blocking. First, one of the forcing mechanisms must be in operation, and second, the phase of the antecedent planetary-scale waves must be such that the forcing mechanism can amplify them into a blocking pattern. In each of the cases studied, the blocking developed downstream of intense intermediate- or large-scale cyclogenesis.

Hansen, A. R.↗
NASA NTRS1989

Phase diagram for ammonia-water mixtures at high pressures - Implications for icy satellites

The (NH3)x(H2O)1-x phase diagram for X from 0 to 0.50 has been reexamined at temperatures from 125 K to 400 K and at pressures from 6.0 GPa using diamond anvil cells, and the implications of the findings for icy satellites are addressed. Titan is likely to have a thicker NH3-H2O ocean than previously suspected, because the stability field of NH3-H2O is found to be smaller than previously supposed. The implications for methane and ammonia volcanism on Titan are briefly discussed. The experimentally observed reactivity between the liquid and iron may also have implications for planetary and satellite evolution.

Cynn, H. C.↗
NASA NTRS1994

MUADEE: Mars Upper Atmosphere Dynamics, Energetics, and Evolution discovery mission. Executive summary volume

This document is the final report of the MAUDEE (Mars Upper Atmosphere Dynamics, Energetics, and Evolution) consortium. It describes a low cost Discovery mission to investigate the upper atmosphere of Mars and to understand the manner in which Mars has evolved over geologic time. In keeping with the innovative philosophy permeating the Discovery Program and in order to minimize the burden of reading an extensive prose exposition, a new presentation format has been adopted. The format involves a series of view graphs with facing text. The view graphs form the basis of a complete oral presentation of the MAUDEE mission and the facing text provides more detailed, but still brief, explanatory descriptions. Readers can scan the view graphs and/or read the facing text at their discretion. The oral presentation of this study was given to code SL personnel at NASA Headquarters on February 23, 1994. MAUDEE is an essential component of the Mars Exploration Program. It provides the information required to understand the evolution of the planet via the escape of volatiles. It provides the key measurements needed to understand the upper atmosphere of the last of the three terrestrial planets to be so studied. It connects and supplements investigations based on other Mars missions: Mars Surveyor, Planet-B and Mars-96. The MAUDEE mission plan involves a combination of remote and in-situ sensors, housed in three instrument packages. The sensors make measurements of the atmospheric regions between 60-200 km. These instruments are based on extensive heritage from Earth explorers and Pioneer Venus. The mission scenario has several phases and employs aerobraking maneuvers to lower initial apoapsis, thereby reducing fuel requirements. The spacecraft has body-mounted solar cells, enabling deep diving into the Martian atmosphere. The orbital inclination allows for pole-to-pole latitudinal sweeps in an initial elliptical phase, followed by a circular phase affording detailed diurnal measurements. The nominal mission duration at Mars is one Mars year.

Killeen, Timothy L.↗
NASA NTRS1995

Recurrent structures of the interplanetary magnetic field observed by Ulysses

Since its launch in October 1990, Ulysses has provided good quality magnetic field data, practically covering the whole time interval until now. We have studied the very long time scale evolution of the interplanetary magnetic field, in particlular, we have search for recurrent disturbances in the magnetic field. The magnetic field vectors have been mapped back to the Sun along Parker spirals, in order to determine the Heliographic longitude of the source regions in the corona. It was found that the position of many high field sources drifts systematically relative to the corona assumed to rotate with the equatorial rotation period of the Sun. The results are compared to similar observations on the eastward drift of magnetic sectors observed after about June 1992. Changes associated with both the declining phase of the solar cycle and the latitudinal excursion of Ulysses are also discussed.

Erdos, G.↗
NASA NTRS2010

Implications of the Secondary Eclipse of Exoplanet HAT-P-11b

We observed exoplanet HAT-P-11b and have successfully detected its secondary eclipse. We conducted observations using the Spitzer Space Telescope in the post-cryo mission at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Having detected the secondary eclipse, we are at present making a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-11b is one of only two known exo-Neptunes and has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary eclipse will serve to clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. We discuss implications of these observations.

Barry, Richard K.↗
NASA NTRS2015

Majorite-Garnet Partitioning of the Highly Siderophile Elements: New Results and Application to Mars

HSE and Os isotopes are used to constrain processes such as accretion, mantle evolution, crustal recycling, and core-mantle mixing, and to constrain the timing and depth of differentiation of Mars. Although showed that the HSE contents of the martian mantle could have been established by metal-silicate equilibrium in early Mars, the role of a cooling magma ocean and associated crystallization in further fractionating the HSEs is unclear. Garnet is thought to have played an important role in controlling trace element concentrations in the martian mantle reservoirs. However, testing these models, including Os isotopes, has been hindered by a dearth of partitioning data for the HSE in deep mantle phases - majorite, wadsleyite, ringwoodite, akimotoite - that may be present in the martian mantle. We examine the partitioning behavior of HSEs between majorite garnet (gt), olivine (oliv), and silicate liquid (melt).

Danielson, L. R.↗