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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

The spatial extent of the 3.3 micron emission feature in the Seyfert galaxy NGC 7469

Observations have been made of the 3.3-micron feature and the infrared continuum in the type 1 Seyfert galaxy NGC 7469 using multiaperture techniques. While as much as 10 to the 7th solar luminosities in 3.3-micron line emission may arise from within the nucleus, the data indicate that the 3.3-micron emission-line region is extended, with a significant fraction of the luminosity of the line originating at distances greater than 240 pc from the nucleus. Possible mechanisms for the heating of the dust associated with the extended emission are discussed together with observational tests which can be used to verify the more promising of these mechanisms.

Cutri, R. M.↗
NASA NTRS1995

Long Duration Exposure Facility

The Long Duration Exposure Facility (LDEF) materials were useful for testing technical concepts that needed to be validated for the Cosmic Dust Collector Facility (CDCF) - a large instrument that was under study for inclusion on the upcoming Space Station. As it turned out, CDCF, which was approved at one point as an external payload, was ultimately canceled due to the scaling back of the Space Station capabilities. However, the study of cosmic dust is still a field of great interest for NASA, being the crucial part of at least one experiment that is still being considered for a Discovery mission. The optimum analysis of hypervelocity impacts is thus a continuing NASA concern. Two experiments, AO187-1 and AO187-2 were explicitly designed to measure the flux and composition of dust particles impacting LDEF. The former consisted of flat targets of Au and Al while the second comprised a set of 237 "capture cells" using Ge target plates covered by thin (2.5 microns) metallized plastic foils. The spacecraft maintained a constant orientation with respect to its velocity vector thereby defining leading and trailing edges that faced respectively into and away from the direction of motion. Both AO187-1 and AO187-2 had detectors on both the leading and trailing edges of LDEF. It was expected that interplanetary dust particles would dominate impacts on the trailing edge while the leading edge would be exposed to both cosmic dust and particles of orbital manmade debris. In AO187-1, the compositions of the impactors was determined by SEM-EDS techniques; in AO187-2 a sensitive surface analysis technique - SIMS - was used to determine both elemental and (some) isotopic compositions. In the initial analysis of AO187-2, it was found that SIMS was more sensitive for the analysis of thin impact debris layers than SEM-EDS. The present grant was made to determine if SIMS analysis could also be applied to impacts recorded in the Au surfaces of AO187-1. Success would extend the analysis of AO187-1 and would also contribute important technical information for the design of future cosmic dust space missions. The results obtained with this grant are incorporated in the attached paper presented at the Third LDEF Symposium and are briefly summarized here. In addition, we comment on the potential implications of this work for future research.

Source record↗
NASA NTRS2003

STS-107 Flight Day 4 Highlights

This fourth flight day of the STS-107 mission begins with a view of the moon from a camera inside of the payload bay of the Space Shuttle Columbia. Presentations of the scientific experiments inside the Spacehab double module are presented. Mission Specialist Michael Anderson is shown working on the combustion module 2, Mission Specialist Kalpana Chawla is shown performing a soot test, Payload Specialist Ilan Ramon is working on the Mediterranean Israeli Dust Experiment (MEIDEX), and Commander Rick Husband is shown studying the mechanics of granular materials. A panoramic view of the pass over Saudi Arabia and the Persian Gulf are shown.

Source record↗
NASA NTRS2008

Lead Paint Exposure Assessment in High Bays of Johnson Space Center

This slide presentation reviews the program to assess the possibility of lead paint exposure in the high bays of some of the Johnson Space Center buildings. Some of the buildings in the Manned Space Flight Center (MSC) were built in 1962 and predate any considerations to reduce lead in paints and coatings. There are many of these older buildings that contain open shops and work areas that have open ceilings, These shops include those that had operations that use leaded gasoline, batteries, and lead based paints. Test were planned to be conducted in three phases: (1) Surface Dust sampling, (2) personal exposure montioring, and (3) Ceiling paint Sampling. The results of the first two phases were reviewed. After considering the results of the first two phases, and the problems associated with the retrieval of samples from high ceilings, it was determined that the evaluation of ceiling coatings would be done on a project by project and in response to a complaint.

Stanch, Penney↗
NASA NTRS2015

Metal-Poor, Strongly Star-Forming Galaxies in the DEEP2 Survey: The Relationship Between Stellar Mass, Temperature-Based Metallicity, and Star Formation Rate

We report on the discovery of 28 redshift (z) approximately equal to 0.8 metal-poor galaxies in DEEP2. These galaxies were selected for their detection of the weak [O (sub III)] lambda 4363 emission line, which provides a "direct" measure of the gas-phase metallicity. A primary goal for identifying these rare galaxies is to examine whether the fundamental metallicity relation (FMR) between stellar mass, gas metallicity, and star formation rate (SFR) holds for low stellar mass and high SFR galaxies. The FMR suggests that higher SFR galaxies have lower metallicity (at fixed stellar mass). To test this trend, we combine spectroscopic measurements of metallicity and dust-corrected SFR with stellar mass estimates from modeling the optical photometry. We find that these galaxies are 1.05 plus or minus 0.61 dex above the redshift (z) approximately 1 stellar mass-SFR relation and 0.23 plus or minus 0.23 dex below the local mass-metallicity relation. Relative to the FMR, the latter offset is reduced to 0.01 dex, but significant dispersion remains dex with 0.16 dex due to measurement uncertainties). This dispersion suggests that gas accretion, star formation, and chemical enrichment have not reached equilibrium in these galaxies. This is evident by their short stellar mass doubling timescale of approximately equal to 100 (sup plus 310) (sub minus 75) million years which suggests stochastic star formation. Combining our sample with other redshift (z) of approximately 1 metal-poor galaxies, we find a weak positive SFR-metallicity dependence (at fixed stellar mass) that is significant at 94.4 percent confidence. We interpret this positive correlation as recent star formation that has enriched the gas but has not had time to drive the metal-enriched gas out with feedback mechanisms.

Metal-Poor↗
NASA NTRSDate not supplied

Electrostatic Discharge Hazard in Spacesuits

Triboelectric charging with a resultant electrostatic discharge is a phenomenon with which most people are familiar, especially those living in dry climates. Spacesuits, which are elaborately designed anthropomorphic pressure vessels attempting to match the motions of the human body while providing protections from the harsh environment of space, also must contend with triboelectric charging. But for spacesuits, which operate with elevated oxygen concentrations (usually >95%) in order to enable the lowest reasonable working pressure for the human operator, additional challenges are present with potentially catastrophic results if those challenges are not met successfully. A painful spark discharge can offer as much as 15kV with an energy transfer as high as 15-20mJ. This is well above the level needed to ignite hydrocarbon vapors or fine dusts such as those in grain silos. There have been several test methods beyond the scope of this paper seeking to address the mechanistic ignition energies to ignite suit materials with a wide possible range of results due to the varied test configurations. What is not known is if the suit materials offer sufficient capability for triboelectric charge generation and discharge to generate the potential and the resultant discharge energies within the ranges needed to ignite the suit materials in this operating environment.

Colin Campbell↗
NASA NTRS2022

Environmental Testing of the OVEN System for Lunar Water Extraction and Prospecting

Introduction: The presence of water ice in permanently shadowed regions on the lunar surface [1] may enable a sustained human presence on the Moon with minimal need for consumables. However, in order to develop a long term utilization plan that includes the usage of in-situ water we must first understand the abundance, stratigraphy and distribution of this re-source. Multiple space agencies currently have plans for lunar water prospecting missions. The Optimized Volatile Extraction Node (OVEN) was designed for water prospecting missions that require samples to be weighed, sealed, and heated as the means of determining water concentration. This method of water quantification necessitates a fair amount of automation, so a rigorous environmental test program was performed in order to build confidence in the performance of the OVEN design. The work presented here describes the OVEN environmental test program as well as ongoing efforts to improve on the design. Vibration: The OVEN participated in two rounds of random vibration tests. The first test was a stand-alone test performed at the Energy Systems Test Area of the Johnson Space Center. The second test was an integrated test with the mobile platform developed for the Resource Prospector project. The OVEN survived both tests without damage, but the tests did provide valuable lessons learned with regards to specific operations. Thermal Vacuum: The OVEN was successfully demonstrated at a temperature range of -50 to 75 C in a thermal vacuum chamber. The need to heat motor gearboxes at lower temperatures was predetermined so this test program was completed by implementing a method of gearbox heating that used the existing circuitry within the motors. Dust: A custom dynamometer was built in order to determine the torque required to move the various mechanisms within the OVEN at a range of temperatures. The OVEN system was coated with lunar dust simulant in order to determine mechanism torques under a worst-case operating condition. Sublimation: Sublimation losses within the OVEN were quantified through a series of test configurations, including an integrated test in a thermal vacuum chamber at Glenn Research Center [2]. Current Work: The OVEN subsystem is currently not a component of any existing prospecting missions, but work continues that will take the lessons learned from previous environmental tests and improve on the design in order to be considered for future prospecting opportunities. References: [1] Colaprete, A., Schultz, P., Heldmann, J., Wooden, D., Shirley, M., Ennico, K., ... & Sollitt, L. (2010). Detection of water in the LCROSS ejecta plume. science, 330(6003), 463-468. [2] Kleinhenz, J., Smith, J., Roush, T., Colaprete, A., Zacny, K., Paulsen, G., ... & Paz, A. (2018). Volatiles Loss from water bearing regolith simulant at Lunar Environments. In Earth and Space 2018: Engineering for Extreme Environments (pp. 454-466). Reston, VA: American Society of Civil Engineers.

A Paz↗
NASA NTRS2020

A Large, Deep 3 Deg2 Survey of Hα, [OIII], and [OII] Emitters from LAGER: Constraining Luminosity Functions

We present our measurements of the Hα, [OIII], and [O II] luminosity functions as part of the Lyman Alpha Galaxies at Epoch of Reionization (LAGER) survey using our samples of 1577 z=0.47Hα-, 3933 z=0.93 [O III]-, and 5367 z=1.59 [O II]-selected emission line galaxies in a 3 deg2 single, CTIO/Blanco DECam pointing of the COSMOS field. Our observations reach 5σ depths of 8.2 × 10−18 erg s−1 cm−2 and comoving volumes of (1−7) × 105 Mpc3 making our survey one of the deepest narrow-band surveys. We select our emission line galaxies via spectroscopic confirmation, photometric redshifts, and colour–colour selections. We measure the observed luminosity functions for each sample and find best fits of φ* = 10−3.16+0.09 −0.09 Mpc−3and L* = 1041.72+0.09 −0.09 erg s−1 for Hα, φ* = 10−2.16+0.10−0.12 Mpc−3 and L* = 1041.38+0.07 −0.06 erg s−1 for [O III], and φ* = 10−1.97+0.07−0.07 Mpc−3 and L* = 1041.66+0.03−0.03 erg s−1 for [OII], with α fixed to −1.75, −1.6, and −1.3, respectively. An excess of bright >1042 erg s−1 [O III] emitters is observed and may be due to active galactic nucleus (AGN) contamination. Corrections for dust attenuation are applied assuming AHα = 1 mag. We also design our own empirical restframe g − r calibration using SDSS DR12 data, test it against our z = 0.47 Hα emitters with zCOSMOS 1D spectra, and calibrate it for (g − r) between −0.8 and 1.3 mag. Dust and AGN corrected star formation rate densities (SFRDs) are measured as log10ρSFR/(Msun yr−1 Mpc−3)=−1.63 ± 0.04, −1.07 ± 0.06, and −0.90 ± 0.10 for Hα, [OIII], and [O II], respectively. We find our [O III] and [O II] samples fully trace cosmic star formation activity at their respective redshifts in comparison to multiwavelength SFRDs, while the Hα sample traces ∼70 per cent of the total z = 0.47 SFRD.

galaxies↗
NASA NTRS2012

Test Before You Fly - High Fidelity Planetary Environment Simulation

The lunar surface environment will present many challenges to the survivability of systems developed for long duration lunar habitation and exploration of the lunar, or any other planetary, surface. Obstacles will include issues pertaining especially to the radiation environment (solar plasma and electromagnetic radiation) and lunar regolith dust. The Planetary Environments Chamber is one piece of the MSFC capability in Space Environmental Effects Test and Analysis. Comprised of many unique test systems, MSFC has the most complete set of SEE test capabilities in one location allowing examination of combined space environmental effects without transporting already degraded, potentially fragile samples over long distances between tests. With this system, the individual and combined effects of the lunar radiation and regolith environment on materials, sub-systems, and small systems developed for the lunar return can be investigated. This combined environments facility represents a unique capability to NASA, in which tests can be tailored to any one aspect of the lunar environment (radiation, temperature, vacuum, regolith) or to several of them combined in a single test.

Craven, Paul↗
NASA NTRS1986

Coma morphology and dust-emission pattern of periodic Comet Halley. IV - Spin vector refinement and map of discrete dust sources for 1910

A hypothetical continuous ejection of dust from discrete emission sources on the sunlit hemisphere of a rotating comet nucleus is tested against 34 digitally processed plates of Comet Halley over the May 5-June 6, 1910 period, as well as the reported projected lengths of six antisunward jets observed between May 14 and June 6, 1910. A map of the comet's nucleus is presented of whose 13 discrete dust sources only two can be modeled as point-like regions. Attention is given to curious cases of 'chain' activation in which the sources that intersect one another on the surface emit dust sequentially, in successive rotations.

Sekanina, Z.↗
NASA NTRS2021

Conceptualizing the Impact of Dust Contaminated Infrared Radiances on Data Assimilation for Numerical Weather Prediction

Numerical weather prediction systems depend on Hyperspectral Infrared Sounder (HIS) data, yet the impacts of dust-contaminated HIS radiances on weather forecasts has not been quantified. To determine the impact of dust aerosol on HIS radiance assimilation, we use a modified radiance assimilation system employing a one-dimensional variational assimilation system (1DVAR) developed under the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Numerical Weather Prediction–Satellite Application Facility (NWP-SAF) project, which uses the Radiative Transfer for TOVS (RTTOV). Dust aerosol impacts on analyzed temperature and moisture fields are quantified using synthetic HIS observations from rawinsonde, Micropulse Lidar Network (MPLNET), and Aerosol Robotic Network (AERONET). Specifically, a unit dust aerosol optical depth (AOD) contamination at 550 nm can introduce larger than 2.4 and 8.6 K peak biases in analyzed temperature and dewpoint, respectively, over our test domain. We hypothesize that aerosol observations, or even possibly forecasts from aerosol predication models, may be used operationally to mitigate dust induced temperature and moisture analysis biases through forward radiative transfer modeling.

Jared W. Marquis↗
NASA NTRS2021

Conceptualizing the Impact of Dust-Contaminated Infrared Radiances on Data Assimilation for Numerical Weather Prediction

Numerical weather prediction systems depend on Hyperspectral Infrared Sounder (HIS) data, yet the impacts of dust-contaminated HIS radiances on weather forecasts has not been quantified. To determine the impact of dust aerosol on HIS radiance assimilation, we use a modified radiance assimilation system employing a one-dimensional variational assimilation system (1DVAR) developed under the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Numerical Weather Prediction–Satellite Application Facility (NWP-SAF) project, which uses the Radiative Transfer for TOVS (RTTOV). Dust aerosol impacts on analyzed temperature and moisture fields are quantified using synthetic HIS observations from rawinsonde, Micropulse Lidar Network (MPLNET), and Aerosol Robotic Network (AERONET). Specifically, a unit dust aerosol optical depth (AOD) contamination at 550 nm can introduce larger than 2.4 and 8.6 K peak biases in analyzed temperature and dewpoint, respectively, over our test domain. We hypothesize that aerosol observations, or even possibly forecasts from aerosol predication models, may be used operationally to mitigate dust induced temperature and moisture analysis biases through forward radiative transfer modeling.

Jared W Marquis↗
NASA NTRSDate not supplied

Developing Wear-Resistant Coatings for Lunar Dust Tolerant Applications

Materials resistant to the harsh lunar environment are needed to support long duration, sustainable missions on the Moon’s surface. Lunar dust poses a significant threat to the durability of components and vehicles due to its fine, jagged morphology and highly abrasive nature. These properties result in particles eroding, adhering and/or embedding onto component surfaces and into device confined geometries (e.g., gear housing, interlocking systems, etc.) potentially leading to premature failure. The aim of this work is to identify and characterize wear-resistant materials for use as protective coatings to minimize abrasion caused by lunar dust.Concurrently, testing and evaluation methods will be devised to elucidate and mimic aspects of lunar dust degradation, including particle embedding, gouging and erosion caused by high velocity impact events. Discussion on balancing the need for dust management and tolerance versus dust adhesion mitigation will be shared in context of relevant lunar applications within the NASA Lunar Occupancy Dust Surface Separation Technologies (LO-DuSST) effort, which is part of a NASA-wide effort to enable a sustained lunar presence through the Lunar Surface Innovation Initiative (LSII).

Materials, Coatings, lunar dust management/mitigat↗
NASA NTRS1977

Data analysis to separate particles of different speed regimes and charges

Although the instruments on the lunar ejecta and meteorite experiment (LEAM) and the Pioneer 8 and 9 space probes were essentially similar, a comparison of their results indicates that different sets of particles caused the different responses. On Pioneer, the events were caused by the impact of cosmic dust, the so-called beta particles expelled from the vicinity of the sun by solar radiation pressure, augmented by extremely high energy but definitely identifiable interstellar grains. On the moon, the events were due to the impact of slowly moving, highly charged lunar dust being propelled electrostatically across the terminator. Both theoretical analysis and experimental testing confirming these conclusions are discussed.

Wolf, H.↗
NASA NTRS1985

Photochemical reactions in interstellar grains photolysis of CO, NH3, and H2O

The interstellar grains are currently considered to be the basic building blocks of comets and, possibly, meteorites. To test this theory, a simulation of the organic layer accreted onto interstellar dust particles was prepared by slow deposition of a CO:NH3:H2O gas mixture on an Al block at 10 K, with concomitant irradiation with vacuum UV. The results of the HPLC and IR analyses of the nonvolatile residue formed by photolysis at 10 K are compared with those observed at 77 K and 298 K. Some of the compounds that may be present on the surfaces of interstellar dust particles have been identified, and some specific predictions concerning the types of molecular species present in comets could be drawn. The results also suggest that photochemical reactions may have been important for the formation of meteorite components. The implication of the findings to the questions of the source of organic matter on earth and the origin of life are discussed.

Agarwal, V. K.↗
NASA NTRS1987

Experimental studies of collision and fragmentation phenomena

The reduction and publication of an extensive data set collected in experiments over several years at Ames and PSI is briefly examined. Hartmann has been assembling data sets from his experiments on catastrophic fragmentation of various materials, including basalt, other igneous rock, ice, and weak dirt clods. Weidenschilling and Davis have continued to gather and reduce data on oblique impacts. The data indicate a power law distribution of ejecta mass vs. velocity, with a slope that is independent of azimuth, and does not vary with impact angle from normal impacts to at least 75 deg from vertical. In order to improve models of coagulation of dust aggregates in the solar nebula, SJW developed an apparatus for drop tests of fragile projectiles. Davis and Weidenschilling continued to collect and analyze experimental data on collisional catastrophic disruption at the Ames Vertical Gun Range.

Hartmann, William K.↗
NASA NTRS1992

A Center for Extraterrestrial Engineering and Construction (CETEC)

A group of knowledgeable scientists and engineers in New Mexico has recognized the need for such a testing capability and has proposed a project to evelop an extraterrestrial surface simulation facility. A group of universities, national laboratories, and private industrial firms is proposing to establish a Center for Extraterrestrial Engineering and Construction (CETEC) and to develop large extraterrestrial surface simulation facilities in which this needed testing can be realistically performed. The CETEC is envisioned to be both a center of knowledge and data regarding engineering, construction, mining, and material process operations on extraterrestrial bodies and a set of extraterrestrial surface simulation facilities. The primary CETEC facility is proposed to be a large domed building made of steel reinforced concrete with more than one acre of test floor area covered with several feet of simulated lunar soil and dust. Various aspects of the project are presented in viewgraph form.

Leigh, Gerald G.↗