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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 NTRS1977

Pulse profile and refined orbital elements for SMC X-1

Results of a reanalysis of SAS-3 data for SMC X-1, including greatly improved orbital elements, are presented. These elements, when combined with newly available data for the optical companion, Sk 160, yield improved estimates for the masses of SMC X-1 and Sk 160. A significant rate of change of intrinsic pulse period is detected during the course of the four-day observation which is consistent with the average value that was previously deduced from observations separated by 5 years. The X-ray pulse profile, averaged over one orbital cycle and with approximately 15-ms time resolution, is also presented. The pulse profile is found to be constant to within statistics, as a function of orbital phase. The implications of the small observed eccentricities of SMC X-1 and other binary X-ray pulsar systems are discussed.

Primini, F.↗
NASA NTRS1995

Compact, low profile antennas for MSAT and mini-M and Std-M land mobile satellite communications

CAL Corporation has developed a new class of low profile radiating elements for use in planar phased array antennas. These new elements have been used in the design of a low cost, compact, low profile antenna unit for MSAT and INMARSAT Mini-M land mobile satellite communications. The antenna unit which measures roughly 32 cm in diameter by 5 cm deep incorporates a compact LNA and diplexer unit as well as a complete, low cost, beam steering system. CAL has also developed a low profile antenna unit for INMARSAT-M land mobile satellite communications. A number of these units, which utilize a microstrip patch array design, were put into service in 1994.

Strickland, P. C.↗
NASA NTRS1999

Recent Development in the Analytical Investigation of Shipboard Rotorcraft Engage and Disengage Operations

This paper presents an overview of recent developments in an effort to predict transient aeroelastic rotor response during shipboard engage and disengage sequences. The blade is modeled as an elastic beam undergoing in flap, lag, extension and torsion. The blade equations of motion are formulated using Hamilton's principle and they are spatially discretized using the finite element method. The discretized blade equations of motion are integrated for a specified rotor speed run-up or run-down profile. Blade element theory is used to calculate quasi-steady or unsteady aerodynamic loads in linear and nonlinear regimes. The analysis is capable of simulating both articulated, hingeless, and gimballed rotor systems. Validation of the rotor code is discussed, including correlation with droop stop impact tests and wind tunnel experiments. Predictions of safe engagement and disengagement envelopes, limited by excessive blade tip deflections or hub moments, are presented. Future directions of study are also discussed.

Smith, Edward C.↗
NASA NTRS1971

Absolute intensity calibrations of solar K line profiles

Individual K-line profiles from elements of fine structure on the surface of the sun are calibrated absolutely. The continuum calibrations of Labs and Neckel and of Houtgast and Namba are considered, and the average K-profile is scaled to that of White and Suemoto. The ranges of intensities across a high-resolution spectrogram are tabulated for various parts of the line profile. Although the spatially-averaged value for K3 of 4.2% of the continuum corresponds to a brightness temperature of 4155 deg K, minimum and maximum values were 3980 and 4360 K, respectively. Similarly, K2v ranges from 4200 to 4560 K, and K2r from 4180 to 4460 K in small elements about 1 arc sec across.

Pasachoff, J., M.↗
NASA NTRSDate not supplied

P-band Antenna Array for NASA's Space Exploration Synthetic Aperture Radar (SESAR) Instrument

A dual-polarized, wideband, lightweight P-band (435 MHz) antenna element and array for spaceborne radar applications has been developed for NASA’s SESAR (Space Exploration Synthetic Aperture Radar) instrument for planetary synthetic aperture radar (SAR) applications. The antenna array is based on lightweight, low-profile antenna elements that form the building blocks of configurable “array panels” that can in turn be used to build larger arrays consisting of multiple panels. The element design combines a novel, mostly planar conductor antenna element geometry with a robust lightweight composite material construction.

Synthetic Aperture Radar↗
NASA NTRS1977

Laser-zone growth in a Ribbon-To-Ribbon (RTR) process silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

The Ribbon-to-Ribbon (RTR) approach to silicon ribbon growth was investigated. An existing RTR apparatus, RTR#1, was upgraded to allow for 5 cm wide ribbon growth with a finite stroke length of at least 15 cm. A second RTR apparatus, RTR#2, was designed, built, and operated which utilizes continuous feed mechanisms and allows continuous growth of 7.5 cm wide ribbons. RTR#2 includes development and utilization of advanced beam scanning (or shaping), high power lasers, and thermal profile modification elements to attain maximum growth velocities (with a design goal of 18 cm/min). Materials studies, process development, and thermal analyses are also described. Residual stresses and dislocation densities were minimized through theoretical and experimental efforts towards optimization of thermal profiles. Growth runs were performed on RTR#2 and solar cells were fabricated which demonstrated efficiencies greater than 10%.

Gurtler, R. W.↗
NASA NTRS2017

Application of New Partition Coefficients to Modeling Plagioclase

Previously, studies that determined the partition coefficient for an element, i, between plagioclase and the residual basaltic melt (Di plag) have been conducted using experimental conditions dissimilar from the Moon, and thus these values are not ideal for modeling plagioclase fractionation in a lunar system. However, recent work [1] has determined partition coefficients for plagioclase at lunar oxygen fugacities, and resulted in plagioclase with Anorthite contents ≥An90; these are significantly more calcic than plagioclase in previous studies, and the An content has a profound effect on partition coefficient values [2,3]. Plagioclase D-values, which are dependent on the An content of the crystal [e.g., 2-6], can be determined using published experimental data and the correlative An contents. Here, we examine new experimental data from [1] to ascertain their effect on the calculation of equilibrium liquids from Apollo 16 sample 60635,2. This sample is a coarse grained, subophitic impact melt composed of ~55% plagioclase laths with An94.4-98.7 [7,8], distinctly more calcic than of previous partition coefficient studies (e.g., [3-6, 9-10]). Sample 60635,2 is notable as having several plagioclase trace element analyses containing a negative Europium anomaly (-Eu) in the rare-earth element (REE) profile, rather than the typical positive Eu anomaly (+Eu) [7-8] (Fig. 1). The expected +Eu is due to the similarity in size and charge with Ca2+, thereby allowing Eu2+ to be easily taken up by the plagioclase crystal structure, in contrast to the remaining REE3+. Some 60635,2 plagioclase crystals only have +Eu REE profiles, some only have -Eu REE profiles, and some +Eu and -Eu analyses in different areas on a single crystal [7, 8]. Moreover, there does not seem to be any core-rim association with the +Eu or -Eu analyses, nor does there appear to be a correlation between the size, shape, or location of a particular crystal within the sample and the sign of its Eu anomaly, which suggests a complex evolution. In order to investigate this sample further, we can calculate the equilibrium liquids, but with An contents distinct from previous experimental studies, we must calculate the appropriate partition coefficients for each trace element analysis.

Fagan, A. L.↗
NASA NTRS1977

Carbon distribution profiles in lunar fines

Radial distribution profiles of elemental carbon in lunar soils consisting of particles in the size range of 50 to 150 microns were investigated. Initial experiments on specimen preparation and the analysis of prepared specimens by Auger electron spectrometry (AES) and scanning electron microscopy (SEM) are described. Results from splits of samples 61501,84 and 64421,11, which were mounted various ways in several specimen holders, are presented. A low carbon content was observed in AES spectra from soil particles that were subjected to sputter-ion cleaning with 960eV argon ions for periods of time up to a total exposure for one hour. This ion charge was sufficient to remove approximately 70 nm of material from the surface. All of the physically adsorbed carbon (as well as water vapor, etc.) would normally be removed in the first few minutes, leaving only carbon in the specimen, and metal support structure, to be detected thereafter.

Hart, R. K.↗
NASA NTRS1988

Deccan volcanism at the Cretaceous-Tertiary boundary

The accuracy with which one can claim that Deccan trap volcanism occurred at the Cretaceous-Tertiary boundary (KTB) over a very short time interval is of key importance in deciding whether a volcanic origin of the KTB events should be taken seriously. In the two years since paleomagnetic, paleontological and geodynamic evidence was published, further data have become available and the case now appears to be well constrained. The Ar-40/Ar-39 results from six labs have yielded some 24 reliable plateau ages that narrow the age range to 65 to 69 Ma. Moreover, it appears that a significant part of this range results from inter-lab spread and possible minor alteration. Paleontology demonstrates that volcanism started in the Maestrichtian, more precisely in the A. mayaroensis zone. Paleomagnetism shows that volcanism spanned only 3 chrons and only one correlation remains possible, that of the main central reversed chron with 29R. Therefore, whereas Ar-40/Ar-39 is able only to restrict the duration of volcanism to some 4 Ma, paleomagnetism restricts it to 0.5 Ma. Using some geochemical indicators such as C-13 as proxy, it is suggested that volcanism actually consists of a few shorter events of unequal magnitude. Extrusion rates may be as high as 100 cu km/yr and fissure lengths as long as several 100 km. Such a scenario appears to be at least as successful as others in accounting for most anomalies observed at the KTB. Particularly important are Iridium and other platinum group elements (PGE) profiles, Sr-87/Sr-86, C-13, 0-18, other exotic geochemical signatures, spherules, soot, shocked minerals, selective and stepwise extinctions. The environmental impact of CO2 possibly released during explosive phases of volcanism, and SO2 released during effusive phases, and the ability of volcanism to ensure worldwide distribution of KTB products are now all addressed. In conclusion, the case for a causal link between internal hotspot activity, birth of the Reunion hotspot itself as the Deccan and KTB events appears to rest on an increasingly stronger basis.

Courtillot, V.↗
NASA NTRS1994

Technology Benefit Estimator (T/BEST): User's Manual

The Technology Benefit Estimator (T/BEST) system is a formal method to assess advanced technologies and quantify the benefit contributions for prioritization. T/BEST may be used to provide guidelines to identify and prioritize high payoff research areas, help manage research and limited resources, show the link between advanced concepts and the bottom line, i.e., accrued benefit and value, and to communicate credibly the benefits of research. The T/BEST software computer program is specifically designed to estimating benefits, and benefit sensitivities, of introducing new technologies into existing propulsion systems. Key engine cycle, structural, fluid, mission and cost analysis modules are used to provide a framework for interfacing with advanced technologies. An open-ended, modular approach is used to allow for modification and addition of both key and advanced technology modules. T/BEST has a hierarchical framework that yields varying levels of benefit estimation accuracy that are dependent on the degree of input detail available. This hierarchical feature permits rapid estimation of technology benefits even when the technology is at the conceptual stage. As knowledge of the technology details increases the accuracy of the benefit analysis increases. Included in T/BEST's framework are correlations developed from a statistical data base that is relied upon if there is insufficient information given in a particular area, e.g., fuel capacity or aircraft landing weight. Statistical predictions are not required if these data are specified in the mission requirements. The engine cycle, structural fluid, cost, noise, and emissions analyses interact with the default or user material and component libraries to yield estimates of specific global benefits: range, speed, thrust, capacity, component life, noise, emissions, specific fuel consumption, component and engine weights, pre-certification test, mission performance engine cost, direct operating cost, life cycle cost, manufacturing cost, development cost, risk, and development time. Currently, T/BEST operates on stand-alone or networked workstations, and uses a UNIX shell or script to control the operation of interfaced FORTRAN based analyses. T/BEST's interface structure works equally well with non-FORTRAN or mixed software analysis. This interface structure is designed to maintain the integrity of the expert's analyses by interfacing with expert's existing input and output files. Parameter input and output data (e.g., number of blades, hub diameters, etc.) are passed via T/BEST's neutral file, while copious data (e.g., finite element models, profiles, etc.) are passed via file pointers that point to the expert's analyses output files. In order to make the communications between the T/BEST's neutral file and attached analyses codes simple, only two software commands, PUT and GET, are required. This simplicity permits easy access to all input and output variables contained within the neutral file. Both public domain and proprietary analyses codes may be attached with a minimal amount of effort, while maintaining full data and analysis integrity, and security. T/BESt's sotware framework, status, beginner-to-expert operation, interface architecture, analysis module addition, and key analysis modules are discussed. Representative examples of T/BEST benefit analyses are shown.

Generazio, Edward R.↗
NASA NTRS1999

On the Lower Limit of Chondrule Cooling Rates: The Significance of Iron Loss in Dynamic Crystallization Experiments

Lofgren (1989) and the further analysis of Lofgren's 1989 experiments by Jones and Lofgren (1993) established that cooling rates as slow as 5 C/hour produced analog textures and major and minor element zoning profiles in minerals, implying that a lower limit on chondrule cooling rate may be approximately 5 C/hour These results, however, are in conflict with those reported by Radomsky and Hewins (1990). In their paper, Radomsky and Hewins (1990) established a lower limit on chondrule cooling rates of I 100 C/hour a factor of 20 higher than that suggested by Jones and Lofgren (1993). The higher cooling rates suggested by Radomsky and Hewins (1990) have gained considerable favor within the meteoritic community largely because it appears more consistent with the preservation of Na in chondrules, which tends to volatilize at the slower cooling rates. In their study, however, Radomsky and Hewins (1990) did not use Pt hang wires that were coated or saturated with Fe. The lack of such techniques likely facilitated Fe loss from their experimental chondrules to the hang wire during formation (Jones and Lofgren, 1993). The effect of Fe loss could produce an inaccurate determination of cooling rates since these rates are largely determined by the Mg-Fe distributions in individual crystals.

Paque, Julie M.↗
NASA NTRS2015

Evidence of Metasomatism in the Lowest Petrographic Types Inferred from A Na(-), K, Rich Rim Around A LEW 86018 (L3.1) Chondrule

Ordinary chondrites (OCs) represent the most abundant extraterrestrial materials and also record the widest range of alteration of primary, pristine minerals of early Solar system material available for study. Relatively few investigations, however, address: (1) the role of fluid alteration, and (2) the relationship between thermal metamorphism and metasomatism in OCs, issues that have been extensively studied in many other meteorite groups e.g., CV, CO, CR, and enstatite chondrites. Detailed elemental abundances profiles across individual chondrules, and mineralogical studies of Lewis Hills (LEW) 86018 (L3.1), an unequilibrated ordinary chondrite (UOC) of low petrographic type of 3.1 returned from Antarctica, provide evidence of extensive alteration of primary minerals. Some chondrules have Na(-), K(-), rich rims surrounded by nepheline, albite, and sodalite-like Na(-), Cl(-), Al-rich secondary minerals in the near vicinity within the matrices. Although, limited evidences of low temperature (approximately 250 C) fluid-assisted alteration of primary minerals to phyllosilicates, ferroanolivine, magnetite, and scapolite have been reported in the lowest grades (less than 3.2) Semarkona (LL3.00) and Bishunpur (LL3.10), alkali-rich secondary mineralization has previously only been seen in higher grade greater than 3.4 UOCs. This preliminary result suggests highly localized metamorphism in UOCs and widens the range of alteration in UOCs and complicates classification of petrographic type and extent of thermal metamorphism or metasomatism. The work in progress will document the micro-textures, geochemistry (Ba, Ca, REE), and isotopic composition (oxygen, Al(-)- 26 Mg-26) of mineral phases in chondrules and adjoining objects to help us understand the formation scenario and delineate possible modes of metamorphism in UOCs.

Mishra, Ritesh Kumar↗
NASA NTRS1979

The response of a disturbed pipe flow to an upstanding roughness element

The paper describes measurements of mean velocity, turbulence intensity and Reynolds shear stress made downstream of a ring-type roughness element of rectangular cross section situated downstream of an identical element. The distance between the elements was varied, and velocity and turbulence profiles in the wake of the downstream element are compared with wake profiles behind a single element. The results show that the leading element can increase the power law exponent of the velocity profile as the spacing between elements is reduced. Turbulence generated in the wake of the first element raises turbulence intensity in the outer region of the wake of the second. The internal boundary layer originating with the second element grows at a rate which depends on the spacing. It is postulated that the internal boundary layers of subsequent roughness elements are determinants in the formation of a periodic wall layer.

Chang, J.↗
NASA NTRS2013

Wireless autonomous device data transmission

A method of communicating information from a wireless autonomous device (WAD) to a base station. The WAD has a data element having a predetermined profile having a total number of sequenced possible data element combinations. The method includes receiving at the WAD an RF profile transmitted by the base station that includes a triggering portion having a number of pulses, wherein the number is at least equal to the total number of possible data element combinations. The method further includes keeping a count of received pulses and wirelessly transmitting a piece of data, preferably one bit, to the base station when the count reaches a value equal to the stored data element's particular number in the sequence. Finally, the method includes receiving the piece of data at the base station and using the receipt thereof to determine which of the possible data element combinations the stored data element is.

Sammel, Jr., David W.↗
NASA NTRS2001

Thermal Analysis Of The NASA Integrated Vehicle Health Monitoring Experiment Technology For X-Vehicles (NITEX)

The purpose of this project was to perform a thermal analysis for the NASA Integrated Vehicle Health Monitoring (IVHM) Technology Experiment for X-vehicles (NITEX). This electronics package monitors vehicle sensor information in flight and downlinks vehicle health summary information via telemetry. The experiment will be tested on the X-34 in an unpressurized compartment, in the vicinity of one of the vehicle's liquid oxygen tanks. The transient temperature profile for the electronics package has been determined using finite element analysis for possible mission profiles that will most likely expose the package to the most extreme hot and cold environmental conditions. From the analyses, it was determined that temperature limits for the electronics would be exceeded for the worst case cold environment mission profile. The finite element model used for the analyses was modified to examine the use of insulation to address this problem. Recommendations for insulating the experiment for the cold environment are presented, and were analyzed to determine their effect on a nominal mission profile.

Hegab, Hisham E.↗
NASA NTRS2002

Thermal Analysis of the NASA Integrated Vehicle Health Monitoring Experiment Technology for X-Vehicles (NITEX)

The purpose of this project was to perform a thermal analysis for the NASA Integrated Vehicle Health Monitoring (IVHM) Technology Experiment for X-vehicles (NITEX). This electronics package monitors vehicle sensor information in flight and downlinks vehicle health summary information via telemetry. The experiment will be tested on the X-34 in an unpressurized compartment, in the vicinity of one of the vehicle's liquid oxygen tanks. The transient temperature profile for the electronics package has been determined using finite element analysis for possible mission profiles that will most likely expose the package to the most extreme hot and cold environmental conditions. From the analyses, it was determined that temperature limits for the electronics would be exceeded for the worst case cold environment mission profile. The finite element model used for the analyses was modified to examine the use of insulation to address this problem. Recommendations for insulating the experiment for the cold environment are presented, and were analyzed to determine their effect on a nominal mission profile.

Hegab, Hisham E.↗