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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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NASA NTRS1974

Simulation of lunar carbon chemistry. II - Lunar winds contribution

Simulation experiments, computations, and analysis of glassy agglutinates show that a directly condensed lunar wind vapor phase is strongly depleted in carbon and sulfur compounds and may recrystallize rapidly in the lunar thermal cycle and separate from host crystals. Factors preventing identification of low-energy species implanted from the lunar atmosphere are discussed. Computational results indicate that the implanted lunar winds carbon originates both from the vapor phases injected into the lunar atmosphere during thermal metamorphism of mature lunar soil grains and from direct volatization of impacting micrometeorites. It is suggested that microglass splashes and tiny crystalline grains possibly attached to the surface of coarser grains do not affect the characteristics of solar wind carbon chemistry in the lunar soil.

Bibring, J. P.↗

NASA NTRS1977

Two-layer thermal barrier coating for high temperature components

A simple two-layer plasma-sprayed thermal barrier coating system was developed which has the potential for protecting high temperature air-cooled gas turbine components. Of the initially examined coatings, the most promising system is an Ni-16Cr-6Al-0.6Y (in wt%) bond coating (about 0.005 to 0.010 cm thick) and a ZrO2-12Y2O3 (in wt%) thermal barrier coating (about 0.025 to 0.064 cm thick). This thermal barrier substantially lowered the metal temperature of the air-cooled airfoil. The coating withstood 3200 cycles (80 s at 1280 C surface temperature) and 275 cycles (1 hr at 1490 C surface temperature) without cracking or spalling. No separation of the thermal barrier from the bond coating or the bond coating from the substrate was observed.

Stecura, S.↗

NASA NTRS1976

Two-layer thermal barrier coating for turbine airfoils - furnace and burner rig test results

A simple, two-layer plasma-sprayed thermal barrier coating system was developed which has the potential for protecting high temperature air-cooled gas turbine components. Of those coatings initially examined, the most promising system consisted of a Ni-16Cr-6Al-0.6Y (in wt%) thermal barrier coating (about 0.005 to 0.010 cm thick) and a ZrO2-12Y2O3 (in wt%) thermal barrier coating (about 0.025 to 0.064 cm thick). This thermal barrier substantially lowered the metal temperature of an air-cooled airfoil. The coating withstood 3,200 cycles (80 sec at 1,280 C surface temperature) and 275 cycles (1 hr at 1,490 C surface temperature) without cracking or spalling. No separation of the thermal barrier from the bond coating or the bond coating from the substrate was observed.

Stecura, S.↗

NASA NTRS2004

Embedded Heaters for Joining or Separating Plastic Parts

A proposed thermal-bonding technique would make it possible to join or separate thermoplastic parts quickly and efficiently. The technique would eliminate the need for conventional welding or for such conventional fastening components as bolted flanges or interlocking hooks. The technique could be particularly useful in the sign industry (in which large quantities of thermoplastics are used) or could be used to join plastic pipes. A thin sheet of a suitable electrically conductive material would be formed to fit between two thermoplastic parts to be joined (see figure). The electrically conductive sheet and the two parts would be put together tightly, then an electrical current would be sent through the conductor to heat the thermoplastic locally. The magnitude of the current and the heating time would be chosen to generate just enough heat to cause the thermoplastic to adhere to both sides of the electrically conductive sheet. Optionally, the electrically conductive sheet could contain many small holes to provide purchase or to increase electrical resistance to facilitate the generation of heat. After thermal bonding, the electrically conductive sheet remains as an integral part of the structure. If necessary, the electrically conductive sheet can be reheated later to separate the joined thermoplastic parts.

Bryant, Melvin A., III↗

NASA NTRS2006

New Directions for NASA's Advanced Life Support Program

Advanced Life Support (ALS), an element of Human Systems Research and Technology s (HSRT) Life Support and Habitation Program (LSH), has been NASA s primary sponsor of life support research and technology development for the agency. Over its history, ALS sponsored tasks across a diverse set of institutions, including field centers, colleges and universities, industry, and governmental laboratories, resulting in numerous publications and scientific articles, patents and new technologies, as well as education and training for primary, secondary and graduate students, including minority serving institutions. Prior to the Vision for Space Exploration (VSE) announced on January 14th, 2004 by the President, ALS had been focused on research and technology development for long duration exploration missions, emphasizing closed-loop regenerative systems, including both biological and physicochemical. Taking a robust and flexible approach, ALS focused on capabilities to enable visits to multiple potential destinations beyond low Earth orbit. ALS developed requirements, reference missions, and assumptions upon which to structure and focus its development program. The VSE gave NASA a plan for steady human and robotic space exploration based on specific, achievable goals. Recently, the Exploration Systems Architecture Study (ESAS) was chartered by NASA s Administrator to determine the best exploration architecture and strategy to implement the Vision. The study identified key technologies required to enable and significantly enhance the reference exploration missions and to prioritize near-term and far-term technology investments. This technology assessment resulted in a revised Exploration Systems Mission Directorate (ESMD) technology investment plan. A set of new technology development projects were initiated as part of the plan s implementation, replacing tasks previously initiated under HSRT and its sister program, Exploration Systems Research and Technology (ESRT). The Exploration Life Support (ELS) Project, under the Exploration Technology Development Program, has recently been initiated to perform directed life support technology development in support of Constellation and the Crew Exploration Vehicle (CEV). ELS) has replaced ALS, with several major differences. Thermal Control Systems have been separated into a new stand alone project (Thermal Systems for Exploration Missions). Tasks in Advanced Food Technology have been relocated to the Human Research Program. Tasks in a new discipline area, Habitation Engineering, have been added. Research and technology development for capabilities required for longer duration stays on the Moon and Mars, including bioregenerative system, have been deferred.

Barta, Daniel J.↗

NASA NTRS2000

The X-Ray Core of the Low-Luminosity Radio Galaxy 3C346 and ASCA Spectroscopy to Test BL LAC/Radio Galaxy Unification

Radio galaxies are relatively faint sources for Advanced Spacecraft for Cosmology Astrophysics (ASCA), and so in order to get the best possible results from the observations two things have been necessary, both of which delayed the fast preparation of papers. Firstly, the best possible data screening and background subtraction were necessary to improve the signal-to-noise, and all our several initial analysis trials were discarded in favor of using FTOOLS versions 4.1 and above. Secondly, we found that the ASCA spectra were statistically too poor to discriminate well between non-thermal and thermal models, never mind the mixture of the two which we expected on the basis of our ROSAT spatial separation of components in radio galaxies. This means that in each case we have needed to combine the ASCA spectroscopy with analysis of data from other X-ray or radio observations in order to exploit the ASCA data to the full. Our analysis for 3C 346 has yielded the cleanest final result. This powerful radio galaxy at a redshift of 0.161, lies in a poor cluster, which we have separated well from the dominant X-ray component of unresolved emission using a spatial analysis of archival ROSAT data. We were then able to fix the thermal component in our ASCA spectral analysis, and have found evidence that the unresolved emission varied by 32 +/- 13% over the 18 months between the ROSAT and ASCA observations. The unresolved X-ray emission does not suffer from intrinsic absorption, and we have related it to radio structures on both milliarcsecond scales and the arcsecond scales which Chandra can resolve. The source is a target of a Chandra AO2 proposal which we have recently submitted to follow up on our ASCA (and ROSAT) work. 3C 346's orientation to the line of sight is uncertain. However, the absence of X-ray absorption, and the radio/optical/X-ray colors, when combined with with previous radio evidence that the source is a foreshortened radio galaxy of the FRII class, suggest that the radio jets are seen at an angle to the line of sight of about 30 deg, intermediate between the radio-galaxy and quasar classes. The relatively hard ASCA response has allowed us to place an upper limit of 5.6 x 10(exp 43) ergs/ s on the 2-10 keV luminosity of any central X-ray component absorbed bN, gas which might be obscuring the broad-line emission region. Attached to this report is an almost final draft of a paper which we have prepared for submission to the Astrophysical Journal. Our combined ASCA and ROSAT results for NGC 6251 rule out our previously preferred flat-spectrum model and inverse-Compton interpretation for the source based on ROSAT data alone, but a softer X-ray spectrum and moderate absorption bring all the available data (including our early VLA HI measurements) into consistency, and we are reasonably confident that we understand the processes responsible for the X-ray emission. We have made some more sensitive HI absorption measurements which are currently being analyzed, and our plans are to publish our ASCA analysis in conjunction with the new HI results. The ASCA data for NGC 4261 have been difficult to interpret. A re-analysis of our ROSAT data with a wider range of physical parameters brings the ROSAT and ASCA results into reasonable agreement only if the emission from hot gas dominates more than suggested by our earlier work, which is itself unexpected since the radio core is bright and a large jet-related X-ray component would bring the source into agreement with results for others of its type. However, we have recently received our Chandra A01 data for this source, with the spatial resolution which allows us to separate thermal and non-thermal emission components. Our ASCA results will be re-interpreted once the analysis of our Chandra data is complete. The interpretation of the ASCA data for BL Lac object 3C 371 is ongoing, in conjunction with analysis of archival multifrequency data. Radio galaxies are complex in their X-ray properties, and hindsight has shown that the spatial resolution of ASCA is too poor for a reliable interpretation of the data without drawing on other observations. However, the ASCA spectra have made a useful contribution to the interpretation of these sources, and the groundwork is now there for more sensitive work using Chandra and XMM-Newton.

Worrall, Diana↗

NASA NTRS1973

Development of and dynamic studies concerning a cable boom system prototype

The conception of a cable boom system for a scientific spin stabilized satellite led to a flat cable stowed on a drum with a flexlead without conversion to avoid slip rings and to facilitate automatic restowage from any state of deployment. Some dynamic features of the extended cable boom and especially the comparison between round and flat cables were investigated in a phenomenological study using a test rig capable of inducing lateral, torsional and thermal cycling disturbances separately or in any combination.

Bring, G.↗

NASA NTRS1975

Automated space processing payloads study. Volume 2, book 2: Technical report, appendices A through E

Experiment hardware and operational requirements for space shuttle experiments are discussed along with payload and system concepts. Appendixes are included in which experiment data sheets, chamber environmental control and monitoring, method for collection and storage of electrophoretically-separated samples, preliminary thermal evaluation of electromagnetic levitation facilities L1, L2, and L3, and applicable industrial automation equipment are discussed.

Source record↗

NASA NTRS1980

Seismic velocity, attenuation and rheology of the upper mantle

Seismic and rheological properties of the upper mantle in the vicinity of the low-velocity zone are expressed in terms of relaxation by dislocation glide. Dislocation bowing in the glide plane explains seismic velocities and attenuation. Climbing at higher stresses for longer periods of time give the observed viscosity, and explain the low velocity and high temperature attenuation found at seismic frequencies. Due to differing parameters, separate terms for thermal, seismic and rheological lithospheres are proposed. All three lithospheres, however, are related and are functions of temperature, and must be specified by parameters such as period, stress, and stress duration.

Anderson, D. L.↗

NASA NTRS1986

Wall temperature control of low-speed body drag

The use of thermal means to control drag under turbulent boundary layer conditions is examined. Numerical calculations are presented for both skin friction and (unseparated) pressure drag for turbulent boundary-layer flows over a fuselage-like body with wall heat transfer. In addition, thermal control of separation on a bluff body is investigated. It is shown that a total drag reduction of up to 20 percent can be achieved for wall heating with a wall-to-total-freestream temperature ratio of 2. For streamlined slender bodies, partial wall heating of the forebody can produce almost the same order of total drag reduction as the full body heating case. For bluff bodies, the separation delay from partial wall cooling of the afterbody is approximately the same as for the fully cooled body.

Lin, J. C.↗

NASA NTRS1987

On the heating of electrons in the tail of Giacobini-Zinner

Computations for the temperature and density of electrons for Comet Giacobini-Zinner are presented which differ from those of Marconi and Mendis (1986) in the use of recently calculated cooling rates, and in the treating of photoelectrons separately from the thermalized electrons with respect to their collisions with the neutrals. The present temperatures are found to be high relative to the ICE observations, though the calculated densities are consistent with these observations.

Marconi, M. L.↗

NASA NTRS1992

Orbiter attitude design for the Astro-1 Spacelab mission

The methods utilized to design orbiter attitudes that satisfied the various Space Shuttle program and payload constraints of the Astro-1 Spacelab astronomy mission are described. The premission methods developed for attitude design and how those methods were applied to accomplish the large amount of real-time replanning required during the flight are presented. Some of the attitude concerns for Astro-1 included orbiter window thermal constraints, two separate telescope fields-of-view, tracking and data relay satellite Ku-band access, and telescope sun avoidance.

Olsen, C. D.↗

NASA NTRS2002

The Multi-Component Nature of the Vela Pulsar Nonthermal X-ray Spectrum

We report on our analysis of a 274 ks observation of the Vela pulsar with the Rossi X-Ray Timing Explorer (RXTE). The double-peaked, pulsed emission at 2 - 30 keV, which we had previously detected during a 93 ks observation, is confirmed with much improved statistics. There is now clear evidence, both in the spectrum and the light curve, that the emission in the RXTE band is a blend of two separate non-thermal components. The spectrum of the harder component connects smoothly with the OSSE, COMPTEL and EGRET spectrum and the peaks in the light curve are in phase coincidence with those of the high-energy light curve. The spectrum of the softer component is consistent with an extrapolation to the pulsed optical flux, and the second RXTE pulse is in phase coincidence with the second optical peak. In addition, we see a peak in the 2-8 keV RXTE pulse profile at the radio phase.

Harding, Alice K.↗

NASA NTRS2015

Surface Acoustic Wave Monitor for Deposition and Analysis of Ultra-Thin Films

A surface acoustic wave (SAW) based thin film deposition monitor device and system for monitoring the deposition of ultra-thin films and nanomaterials and the analysis thereof is characterized by acoustic wave device embodiments that include differential delay line device designs, and which can optionally have integral reference devices fabricated on the same substrate as the sensing device, or on a separate device in thermal contact with the film monitoring/analysis device, in order to provide inherently temperature compensated measurements. These deposition monitor and analysis devices can include inherent temperature compensation, higher sensitivity to surface interactions than quartz crystal microbalance (QCM) devices, and the ability to operate at extreme temperatures.

Hines, Jacqueline H.↗

NASA NTRS2018

Passive Thermal Management Systems Employing Shape Memory Alloys

A thermal management system includes a first substrate having a first conductive inner surface. A second substrate has a second conductive inner surface. A connecting structure is attached to the first and second substrates to space apart the first and second inner surfaces defining an insulating space for a single architecture. One or more passively-acting elements are attached to the inner surface of at least one substrate and including a shape memory material such as a shape memory alloy (SMA). The SMA passively reacts to the temperature of the first substrate by thermally contacting or separating from the second inner surface of the second substrate for the control of the conduction of heat energy in either direction.

Trigwell, Steven↗

NASA NTRS2013

An Update on the Non-Mass-Dependent Isotope Fractionation under Thermal Gradient

Mass flow and compositional gradient (elemental and isotope separation) occurs when flu-id(s) or gas(es) in an enclosure is subjected to a thermal gradient, and the phenomenon is named thermal diffusion. Gas phase thermal diffusion has been theoretically and experimentally studied for more than a century, although there has not been a satisfactory theory to date. Nevertheless, for isotopic system, the Chapman-Enskog theory predicts that the mass difference is the only term in the thermal diffusion separation factors that differs one isotope pair to another,with the assumptions that the molecules are spherical and systematic (monoatomic-like structure) and the particle collision is elastic. Our previous report indicates factors may be playing a role because the Non-Mass Dependent (NMD) effect is found for both symmetric and asymmetric, linear and spherical polyatomic molecules over a wide range of temperature (-196C to +237C). The observed NMD phenomenon in the simple thermal-diffusion experiments demands quantitative validation and theoretical explanation. Besides the pressure and temperature dependency illustrated in our previous reports, efforts are made in this study to address issues such as the role of convection or molecular structure and whether it is a transient, non-equilibrium effect only.

Sun, Tao↗

NASA NTRS1979

A gas chromatographic air analyzer fabricated on a silicon wafer

A miniature gas analysis system has been built based on the principles of gas chromatography (GC). The major components are fabricated in silicon using photolithography and chemical etching techniques, which allows size reductions of nearly three orders of magnitude compared to conventional laboratory instruments. The chromatography system consists of a sample injection valve and a 1.5-m-long separating capillary column, which are fabricated on a substrate silicon wafer. The output thermal conductivity detector is separately batch fabricated and integrably mounted on the substrate wafer. The theory of gas chromatography has been used to optimize the performance of the sensor so that separations of gaseous hydrocarbon mixtures are performed in less than 10 s. The system is expected to find application in the areas of portable ambient air quality monitors, implanted biological experiments, and planetary probes.

Terry, S. C.↗

NASA NTRS1982

Martian dust mantling and surface composition - Interpretation of thermophysical properties

The goal of the study presented here is to use the diurnal variation of the differences in the brightness temperatures between each of the four surface-sensing IRTM (infrared thermal mapper) wavelength bands to separate the average grain size determined by the thermal inertia into the surface block population and the inertia of the fine component. It is noted that the thermal emissivity of the surface can also be determined and that this in turn can be used to estimate compositional variations. What is more, the atmospheric dust content can be estimated and used to infer sources and sinks of airborne dust. Owing to the number of unknowns, observations at more than one time of day are necessary to determine each of these parameters independently. The data discussed here were obtained by the IRTM, which had five thermal channels centered at 7, 9, 11, 15, and 20 microns and one channel that measured solar reflectance for from 0.3 to 3.0 microns.

Christensen, P. R.↗