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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Lunar oxygen and metal for use in near-Earth space: Magma electrolysis

Because it is energetically easier to get material from the Moon to Earth orbit than from the Earth itself, the Moon is a potentially valuable source of materials for use in space. The unique conditions on the Moon, such as vacuum, absence of many reagents common on the Earth, and the presence of very nontraditional ores suggest that a unique and nontraditional process for extracting materials from the ores may prove the most practical. With this in mind, an investigation of unfluxed silicate electrolysis as a method for extracting oxygen, iron, and silicon from lunar regolith was initiated and is discussed. The advantages of the process include simplicity of concept, absence of need to supply reagents from Earth, and low power and mass requirements for the processing plant. Disadvantages include the need for uninterrupted high temperature and the highly corrosive nature of the high-temperature silicate melts which has made identifying suitable electrode and container materials difficult.

Colson, Russell O.↗
NASA NTRS1990

Relic gravitational waves and extended inflation

In extended inflation, a new version of inflation where the transition from an inflationary to a radiation-dominated universe is accomplished by bubble nucleation, bubble collisions supply a potent - and potentially detectable - source of gravitational waves. The energy density in relic gravitons from bubble collisions is expected to be about 0.00005 of closure density. Their characteristic wavelength depends on the reheating temperature. If black holes are produced by bubble collisions, they will evaporate, producing shorter-wavelength gravitons.

Turner, Michael S.↗
NASA NTRS1990

Conceptual design for a lunar-base CELSS

Future human exploration is key to the United States National Space Policy goal of maintaining a world leadership position in space. In the past, spacecraft life support systems have used open-loop technologies that were simple and sufficiently reliable to demonstrate the feasibility of spaceflight. A critical technology area needing development in support of both long duration missions and the establishment of lunar or planetary bases is regenerative life support. The information presented in this paper describes a conceptual design of a Lunar Base Controlled Ecological Life Support System (LCELSS) which supports a crew size ranging from 4 to 100. The system includes, or incorporates interfaces with, eight primary subsystems. An initial description of the Lunar-Base CELSS subsystems is provided within the framework of the conceptual design. The system design includes both plant (algae and higher plant) and animal species as potential food sources.

Schwartzkopf, Steven H.↗
NASA NTRS1991

Theoretical characterization of the potential energy surface for H + N2 yields HN2. III - Calculations for the excited state surfaces

Additional calculations which characterize potential energy sources (PESs) for the excited 3A-double-prime state, for a bound 2(2A-prime) state, for HN2(+), and for the Rydberg states associated with HN2(+). It is anticipated that these excited state PESs will be important in interpreting and designing experiments to characterize the ground state HN2 species via neutralized ion beam techniques.

Walch, Stephen P.↗
NASA NTRS1991

Nonlocal thermodynamic equilibrium processes in ozone - Implications for the energy budget of the mesosphere and lower thermosphere

The conversion of chemical potential energy and infrared radiative energy to kinetic energy by non-LTE processes involving ozone is a potentially significant source of heat in the terrestrial upper mesosphere and lower thermosphere. Heating rates are calculated and compared using two different statistical equilibrium models previously applied in the analysis of measurements of limb emission from ozone. The calculated heating depends strongly on the assumed distribution and relaxation of energy in the quasi-nascent ozone molecule. Finally, in the absence of a detailed data base of rate coefficients it may be possible to estimate the heating rate due to non-LTE processes in ozone from appropriate satellite measurements of the ozone concentration and of the infrared emission from ozone in the 9-12 micron spectral interval.

Milynczak, Martin G.↗
NASA NTRS1991

Contamination effects on Space Station Freedom electric power system performance

One design issue for Space Station Freedom (SSF) is the potential performance decrease of the electric power system (EPS) solar arrays and radiators as a result of contamination on sensitive surfaces. The authors discuss SSF potential contamination sources and contamination effects on the solar array and radiator performance due to these sources. With these contamination consideration, the SSF EPS is designed for the induced contamination environment at an optimal cost. The efforts on contamination protection and control are undergoing continual update because of the changes in the SSF configuration and in the contamination requirements, and observations from recent flight and laboratory test data are continuously being incorporated into the design.

Lu, Cheng-Yi↗
NASA NTRS1991

Free-piston Stirling component test power converter

The National Aeronautics and Space Administration (NASA) has been evaluating free-piston Stirling power converters (FPSPCs) for use on a wide variety of space missions. They provide high reliability, long life, and efficient operation and can be coupled with all potential heat sources, various heat input and heat rejection systems, and various power management and distribution systems. FPSPCs can compete favorably with alternative power conversion systems over a range of hundreds of watts to megawatts. Mechanical Technology Incorporated (MTI) is developing FPSPC technology under contract to NASA Lewis Research Center and will demonstrate this technology in two full-scale power converters operating at space temperature conditions. The testing of the first of these, the component test power converter (CTPC), was initiated in Spring 1991 to evaluate mechanical operation at space operating temperatures. The CTPC design, hardware fabrication, and initial test results are reviewed.

Dochat, George↗
NASA NTRS1992

Operational strategies for contamination control of composite materials

Composite materials, used on many instruments, are a potential contamination source for sensitive sensors, especially for sensors or detectors cooled below -80 C. It is a well known fact that composite materials absorb water during fabrication, integration, test, and launch activities and desorb this water under vacuum conditions. Water absorption can be divided into two types: shallow water and deep water. Shallow water is generally about 500 A thick on a clean material surface and is easily desorbed under vacuum conditions. Deep water is a function of the material and is absorbed into the bulk of the material. Deep water can outgas for weeks, months, or years, depending on the vent path, the amount of absorbed water, and the temperature of the material. Several operational strategies have been successfully employed on the Wide Field Planetary Camera. The operational strategies include ultradry gaseous nitrogen purge, dew point of less than -80 C, and vacuum bake-out with verification of outgassing rates. The nitrogen purge is instituted during the fabrication phase and is continued through launch activities. Great care is taken to avoid extended periods of time that the material is exposed to the ambient environment (50 percent relative humidity). On-orbit operational strategies include heat-up and cool-down scenarios which allow the deep water to be sufficiently outgassed before cooling the sensors or detectors.

Hansen, Patricia A.↗
NASA NTRS1992

Analytic description of the electron temperature behavior in the upper ionosphere and plasmasphere

Approximate analytic solutions to the well-known and commonly used time-dependent electron energy balance equation for the upper ionosphere and plasmasphere have been obtained and are discussed. The various potential heating sources for the terrestrial plasmasphere are summarized and the corresponding electron temperatures and related characteristic heating and cooling times are calculated. A comparison between the analytic expressions for the temperature variations and relevant measurements shows excellent agreement.

Khazanov, G. V.↗
NASA NTRS1994

Antiproton catalyzed microfission/fusion propulsion

Inertial confinement fusion (ICF) utilizing an antiproton catalyzed hybrid fission/fusion target is discussed as a potential energy source for interplanetary propulsion. A proof-of-principle experiment underway at Phillips Laboratory, Kirtland AFB and antiproton trapping experiments at CERN, Geneva, Switzerland, are presented. The ICAN propulsion concept is described and results of performance analyses are reviewed. Future work to further define the ICAN concept is outlined.

Chiang, Pi-Ren↗
NASA NTRS1994

The early Sun and the formation of chondrules

The early Sun and its proposed role in chondrule formation is presented in this report. The early Sun is an energy source that potentially provides a mechanism for chondrule formation and an explanation for the systematics of chondrule populations. Earlier workers have shown that a T Tauri sun would not supply enough energy to melt dust at the radius of the asteroids. However, recent observations indicate that the T Tauri phase is actually the waning stage of pre-main sequence activity. Pre-main-sequence stars are surrounded by accretion disks and are powered by accretional energy. While still embedded in a molecular-cloud core, these stars often drive massive bipolar outflows of molecular gas that has been swept up and accelerated to tens of km s(exp -1) by a high-velocity stellar wind (hundreds of km s(exp -1)).

Huss, G. R.↗
NASA NTRS1994

Acoustics of laminar boundary layers breakdown

Boundary layer flow transition has long been suggested as a potential noise source in both marine (sonar-dome self noise) and aeronautical (aircraft cabin noise) applications, owing to the highly transient nature of process. The design of effective noise control strategies relies upon a clear understanding of the source mechanisms associated with the unsteady flow dynamics during transition. Due to formidable mathematical difficulties, theoretical predictions either are limited to early linear and weakly nonlinear stages of transition, or employ acoustic analogy theories based on approximate source field data, often in the form of empirical correlation. In the present work, an approach which combines direct numerical simulation of the source field with the Lighthill acoustic analogy is utilized. This approach takes advantage of the recent advancement in computational capabilities to obtain detailed information about the flow-induced acoustic sources. The transitional boundary layer flow is computed by solving the incompressible Navier-Stokes equations without model assumptions, thus allowing a direct evaluation of the pseudosound as well as source functions, including the Lighthill stress tensor and the wall shear stress. The latter are used for calculating the radiated pressure field based on the Curle-Powell solution of the Lighthill equation. This procedure allows a quantitative assessment of noise source mechanisms and the associated radiation characteristics during transition from primary instability up to the laminar breakdown stage. In particular, one is interested in comparing the roles played by the fluctuating volume Reynolds stress and the wall-shear-stresses, and in identifying specific flow processes and structures that are effective noise generators.

Wang, Meng↗
NASA NTRS1994

A cheaper, faster, better way to detect water of hydration on Solar System bodies

The 3.0-micrometers water of hydration absorption feature observed in the IR photometry of many low-albedo and some medium-albedo asteroids strongly correlates with the 0.7-micrometers Fe(+2) to Fe(+3) oxidized iron absorption feature observed in narrowband spectrophotometry of these asteroids. Using this relationship, an empirical algorithm for predicting the presence of water of hydration in the surface material of a Solar System body using photometry obtained through the Eight-Color Asteroid Survey nu (0.550 micrometers), w (0.701 micrometers), and x (0.853 micrometers) filters was developed and applied to the ECAS photometry of asteroids and outer planet satellites. The percentage of objects in low-albedo, outer main-belt asteroid classes that test positively for water of hydration increases from P to B to C to G class and correlates linearly with the increasing mean albedos of those objects testing positively. The medium-albedo M-class asteroids do not test positively in large number using this algorithm. Aqueously altered asteroids dominate the Solar System population between heliocentric distances of 2.6 to 3.5 AU, bracketing the Solar System region where the aqueous alteration mechanism operated most strongly. One jovian satellite, J VI Himalia, and one saturnian satellite. Phoebe, tested positively for water of hydration, supporting the hypothesis that these may be captured C-class asteroids from a postaccretional dispersion. The proposed testing technique could be applied to an Earth-based survey of asteroids or a space-probe study of an asteroid's surface characteristic in order to identify a potential water source.

Vilas, Faith↗
NASA NTRS1993

Investigation of water vapor motion winds from geostationary satellites

Motions deduced in animated water vapor imagery from geostationary satellites can be used to infer wind fields in cloudless regimes. For the past several years, CIMSS has been exploring this potentially important source of global-scale wind information. Recently, METEOSAT-3 data has become routinely available to both the U.S. operational and research community. Compared with the current GOES satellite, the METEOSAT has a superior resolution (5 km vs. 16 km) in its water vapor channel. Preliminary work: at CIMSS has demonstrated that wind sets derived from METEOSAT water vapor imagery can provide important upper-tropospheric wind information in data void areas, and can positively impact numerical model guidance in meteorological applications. Specifically, hurricane track forecasts can be improved. Currently, we are exploring methods to further improve the derivation and quality of the water vapor wind sets.

Velden, Christopher↗
NASA NTRS1994

Investigation of water vapor motion winds from geostationary satellites

Water vapor imagery from geostationary satellites has been available for over a decade. These data are used extensively by operational analysts and forecasters, mainly in a qualitative mode (Weldon and Holmes 1991). In addition to qualitative applications, motions deduced in animated water vapor imagery can be used to infer wind fields in cloudless regimes, thereby augmenting the information provided by cloud-drift wind vectors. Early attempts at quantifying the data by tracking features in water vapor imagery met with modest success (Stewart et al. 1985; Hayden and Stewart 1987). More recently, automated techniques have been developed and refined, and have resulted in upper-level wind observations comparable in quality to current operational cloud-tracked winds (Laurent 1993). In a recent study by Velden et al. (1993) it was demonstrated that wind sets derived from Meteosat-3 (M-3) water vapor imagery can provide important environmental wind information in data void areas surrounding tropical cyclones, and can positively impact objective track forecasts. M-3 was repositioned to 75W by the European Space Agency in 1992 in order to provide complete coverage of the Atlantic Ocean. Data from this satellite are being transmitted to the U.S. for operational use. Compared with the current GOES-7 (G-7) satellite (positioned near 112W), the M-3 water vapor channel contains a superior horizontal resolution (5 km vs. 16 km ). In this paper, we examine wind sets derived using automated procedures from both GOES-7 and Meteosat-3 full disk water vapor imagery in order to assess this data as a potentially important source of large-scale wind information. As part of a product demonstration wind sets were produced twice a day at CIMSS during a six-week period in March and April (1994). These data sets are assessed in terms of geographic coverage, statistical accuracy, and meteorological impact through preliminary results of numerical model forecast studies.

Velden, Christopher S.↗
NASA NTRS1994

An Algorithm to Generate Deep-Layer Temperatures from Microwave Satellite Observations for the Purpose of Monitoring Climate Change

An algorithm for generating deep-layer mean temperatures from satellite-observed microwave observations is presented. Unlike traditional temperature retrieval methods, this algorithm does not require a first guess temperature of the ambient atmosphere. By eliminating the first guess a potentially systematic source of error has been removed. The algorithm is expected to yield long-term records that are suitable for detecting small changes in climate. The atmospheric contribution to the deep-layer mean temperature is given by the averaging kernel. The algorithm computes the coefficients that will best approximate a desired averaging kernel from a linear combination of the satellite radiometer's weighting functions. The coefficients are then applied to the measurements to yield the deep-layer mean temperature. Three constraints were used in deriving the algorithm: (1) the sum of the coefficients must be one, (2) the noise of the product is minimized, and (3) the shape of the approximated averaging kernel is well-behaved. Note that a trade-off between constraints 2 and 3 is unavoidable. The algorithm can also be used to combine measurements from a future sensor (i.e., the 20-channel Advanced Microwave Sounding Unit (AMSU)) to yield the same averaging kernel as that based on an earlier sensor (i.e., the 4-channel Microwave Sounding Unit (MSU)). This will allow a time series of deep-layer mean temperatures based on MSU measurements to be continued with AMSU measurements. The AMSU is expected to replace the MSU in 1996.

Goldberg, Mitchell D.↗
NASA NTRS1995

Characterization of the Minimum Energy Path for the Reaction of Singlet Methylene with N2: The Role of Singlet Methylene in Prompt NO

We report calculations of the minimum energy pathways connecting CH2 + N2 to diazomethane and diazirine, for the rearrangement of diazirine to diazomethane, for the dissociation of diazirine to HCN2+H, and of diazomethane to CH2N+N. The calculations use Complete Active Space Self-Consistent Field (CASSCF) derivative methods to characterize the stationary points and Internally Contracted Configuration Interaction (ICCI) to determine the energetics. The calculations suggest a potential new source of prompt NO from the reaction CH2 with N2 to give diazirine, and subsequent reaction of diazirine with hydrogen abstracters to form doublet HCN2, which leads to HCN+N(S-4) on the previously studied CH+N2 surface. The calculations also predict accurate 0 K heats of formation of 77.7 kcal/mol and 68.0 kcal/mol for diazirine and diazomethane, respectively.

Walch, Stephen P.↗
NASA NTRS1995

Characterization of the Minimum Energy Path for the Reaction of Singlet Methylene with N2: The Role of Singlet Methylene in Prompt NO

We report calculations of the minimum energy pathways connecting (1)CH2+N2 to diazomethane and diazirine, for the rearrangement of diazirine to diazomethane, for the dissociation of diazirine to HCN2+H, and of diazomethane to CH2N+N. The calculations use complete active space self-consistent field (CASSCF) derivative methods to characterize the stationary points and internally contracted configuration interaction (ICCI) to determine the energetics. The calculations suggest a potential new source of prompt NO from the reaction of (1)CH2 with N2 to give diazirine, and subsequent reaction of diazirine with hydrogen abstracters to form doublet HCN2, which leads to HCN+N(S-4) on the previously studied CH+N2 Surface. The calculations also predict accurate 0 K heats of formation of 77.7 kcal/mol and 68.0 kcal/mol for diazirine and diazomethane, respectively.

Walch, Stephen P.↗