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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 343 records · Page 19

Collection of wind-tunnel data on commonly used wing sections

This report groups in a uniform manner the aerodynamic properties of commonly used wing sections as determined from tests in various wind tunnels. The data have been collected from reports of a number of laboratories. Where necessary, transformation has been made to the absolute system of coefficients and tunnel wall interference corrections have been applied. Tables and graphs present the data in the various forms useful to the engineer in the selection of a wing section.

Louden, F A↗

Pressure Fluctuations in a Common-Rail Fuel Injection System

This report presents the results of an investigation to determine experimentally the instantaneous pressures at the discharge orifice of a common-rail fuel injection system in which the timing valve and cut-off valve were at some distance from the automatic fuel injection valve, and also to determine the methods by which the pressure fluctuations could be controlled. The results show that pressure wave phenomena occur between the high-pressure reservoir and the discharge orifice, but that these pressure waves can be controlled so as to be advantageous to the injection of the fuel. The results also give data applicable to the design of such an injection system for a high-speed compression-ignition engine.

Rothrock, A M↗

Space Station Common Berthing Mechanism, a multi-body simulation application

This paper discusses an application of multi-body dynamic analysis conducted at the Boeing Company in connection with the Space Station (SS) Common Berthing Mechanism (CBM). After introducing the hardware and analytical objectives we will focus on some of the day-to-day computational issues associated with this type of analysis.

Searle, Ian↗

Open environments to support systems engineering tool integration: A study using the Portable Common Tool Environment (PCTE)

A study of computer engineering tool integration using the Portable Common Tool Environment (PCTE) Public Interface Standard is presented. Over a 10-week time frame, three existing software products were encapsulated to work in the Emeraude environment, an implementation of the PCTE version 1.5 standard. The software products used were a computer-aided software engineering (CASE) design tool, a software reuse tool, and a computer architecture design and analysis tool. The tool set was then demonstrated to work in a coordinated design process in the Emeraude environment. The project and the features of PCTE used are described, experience with the use of Emeraude environment over the project time frame is summarized, and several related areas for future research are summarized.

Eckhardt, Dave E., Jr.↗

General Monte Carlo reliability simulation code including common mode failures and HARP fault/error-handling

A Monte Carlo Fortran computer program was developed that uses two variance reduction techniques for computing system reliability applicable to solving very large highly reliable fault-tolerant systems. The program is consistent with the hybrid automated reliability predictor (HARP) code which employs behavioral decomposition and complex fault-error handling models. This new capability is called MC-HARP which efficiently solves reliability models with non-constant failures rates (Weibull). Common mode failure modeling is also a specialty.

Platt, M. E.↗

Artemis common lunar lander. Phase 2: Study results for external review

The purpose of the Artemis Program is to gather vital reconnaissance data by conducting robotic exploration missions to the lunar surface both prior to and concurrent with human exploration missions. The Artemis Program includes rapid, near-term development of a variety of small experimental and operational payloads, provides a low-cost capability to deliver these payloads to any location on the lunar surface, and supports the analysis of the data returned. The Artemis Program will improve the understanding of lunar geosciences, demonstrate the Moon's unique capability as an astronomical platform to study the universe, and to conduct scientific and technology development experiments, and will prepare for, enhance, and complement human mission The Artemis Common Lunar Lander Phase 2 Study results for external review are included.

Source record↗

Indications for common origin and gravitational interaction in three binary LMC clusters

Three close pair clusters of the LMC, NGC 2006/SL 538, NGC 2011 a/b, and NGC 2042 a/b, have been studied in order to establish their binarity. The stellar content in the outer region of each cluster has been investigated by means of low resolution objective UK Schmidt prism spectra, the cores of the clusters have been examined using low resolution integrated IUE spectra, whereas their density profiles and their observed dynamical parameters have been derived by means of star counts. The integrated spectra of their cores and the stellar content of their outer cluster regions have shown a common origin and a very young age (less than 2 x 10 exp 7 yr) for each member of the pairs, whereas their dynamical study has shown that they are gravitationally interacting. Comparing the age of their stellar content with their dynamical and relaxation times, it has been found that these clusters are physically associated and had no time to relax by stellar encounters, no time to merge, and no time to be destroyed by dynamical friction.

Kontizas, E.↗

Free-free and fixed base modal survey tests of the Space Station Common Module Prototype

This paper describes the testing aspects and the problems encountered during the free-free and fixed base modal surveys completed on the original Space Station Common Module Prototype (CMP). The CMP is a 40-ft long by 14.5-ft diameter 'waffle-grid' cylinder built by the Boeing Company and housed at the Marshall Space Flight Center (MSFC) near Huntsville, AL. The CMP modal survey tests were conducted at MSFC by the Dynamics Test Branch. The free-free modal survey tests (June '90 to Sept. '90) included interface verification tests (IFVT), often referred to as impedance measurements, mass-additive testing and linearity studies. The fixed base modal survey tests (Feb. '91 to April '91), including linearity studies, were conducted in a fixture designed to constrain the CMP in 7 total degrees-of-freedom at five trunnion interfaces (two primary, two secondary, and the keel). The fixture also incorporated an airbag off-load system designed to alleviate the non-linear effects of friction in the primary and secondary trunnion interfaces. Numerous test configurations were performed with the objective of providing a modal data base for evaluating the various testing methodologies to verify dynamic finite element models used for input to coupled load analysis.

Driskill, T. C.↗

Estimation of grain sizes and mixing ratios of fine powder mixtures of common geologic minerals

Two different approaches for modeling reflectance spectra of intimate mixtures, Hapke's model and the isograin model, are used to estimate grain sizes and mixing ratios of powder mixtures of three geologic minerals: olivine, orthopyroxene, and plagioclase. In Hapke's model, scattering and extinction effiencies are mixed separately, and both models employ semiempirical refractive index spectra for component minerals. Mixing ratios of mixtures of grain size 45-75 micrometers are well estimated by both models assuming a common grain size of 60 micrometers and optimizing the constants for the single-particle scattering. For each model, effective grain size ratios for mineral constituents in mixtures of grain size less than 25 micrometers, are derived successfully that allows mineral abundances to be accurately predicted within approximately 4 wt percent. On the other hand, neither model can accurately predict mineral reflectance spectra for its smaller grain sizes less than 25 and 25-45 micrometers using an absorption coefficient spectrum derived from a larger grain size (45-75 micrometers). The errors in both models are significantly reduced if surface roughness effects of the smaller grain-size fractions are modeled.

Hiroi, Takahiro↗

Polarization Signals of Common Spacecraft Materials

This is the final report documenting the results of the polarization testing of near-planar objects with various reflectance properties. The purpose of this investigation was to determine the portion of the reflected signal which is polarized for materials commonly used in space applications. Tests were conducted on several samples, with surface characteristics ranging from highly reflective to relatively dark. The measurements were obtained by suspending the test object in a beam of collimated light. The amount of light falling on the sample was controlled by a circular aperture placed in the light field. The polarized reflectance at various phase angles was then measured. A nonlinear least squares fitting program was used for analysis. For the specular test objects, the reflected signals were measured in one degree increments near the specular point. Otherwise, measurements were taken every five degrees in phase angle. Generally, the more diffuse surfaces had lower polarized reflectances than their more specular counterparts. The reflected signals for the more diffuse surfaces were spread over a larger phase angle range, while the signals from the more specular samples were reflected almost entirely within five degrees of angular deviation from the specular point. The method used to test all the surfaces is presented. The results of this study will be used to support the NASA Orbital Debris Optical Signature Tests. These tests are intended to help better understand the reflectance properties of materials often used in space applications. This data will then be used to improve the capabilities for identification and tracking of space debris.

Gravseth, Ian↗

National Cycle Program (NCP) Common Analysis Tool for Aeropropulsion

Through the NASA/Industry Cooperative Effort (NICE) agreement, NASA Lewis and industry partners are developing a new engine simulation, called the National Cycle Program (NCP), which is the initial framework of NPSS. NCP is the first phase toward achieving the goal of NPSS. This new software supports the aerothermodynamic system simulation process for the full life cycle of an engine. The National Cycle Program (NCP) was written following the Object Oriented Paradigm (C++, CORBA). The software development process used was also based on the Object Oriented paradigm. Software reviews, configuration management, test plans, requirements, design were all apart of the process used in developing NCP. Due to the many contributors to NCP, the stated software process was mandatory for building a common tool intended for use by so many organizations. The U.S. aircraft and airframe companies recognize NCP as the future industry standard for propulsion system modeling.

Follen, G.↗

Composite, Cryogenic, Conformal, Common Bulkhead, Aerogel-Insulated Tank (CBAT) Materials and Processing Methodologies

A viewgraph presentation outlines the current status and future activities of the composite, cryogenic, conformal, common bulkhead, aerogel-insulated tank (CBAT). Each term (composite, cryogenic, conformal, etc.) is explained. The fabrication method for the CBAT is described, including challenges and their solutions. Near term and long term goals are discussed.

Kovach, Michael P.↗

A Common Calibration Source Framework for Fully-Polarimetric and Interferometric Radiometers

Two types of microwave radiometry--synthetic thinned array radiometry (STAR) and fully-polarimetric (FP) radiometry--have received increasing attention during the last several years. STAR radiometers offer a technological solution to achieving high spatial resolution imaging from orbit without requiring a filled aperture or a moving antenna, and FP radiometers measure extra polarization state information upon which entirely new or more robust geophysical retrieval algorithms can be based. Radiometer configurations used for both STAR and FP instruments share one fundamental feature that distinguishes them from more 'standard' radiometers, namely, they measure correlations between pairs of microwave signals. The calibration requirements for correlation radiometers are broader than those for standard radiometers. Quantities of interest include total powers, complex correlation coefficients, various offsets, and possible nonlinearities. A candidate for an ideal calibration source would be one that injects test signals with precisely controllable correlation coefficients and absolute powers simultaneously into a pair of receivers, permitting all of these calibration quantities to be measured. The complex nature of correlation radiometer calibration, coupled with certain inherent similarities between STAR and FP instruments, suggests significant leverage in addressing both problems together. Recognizing this, a project was recently begun at NASA Goddard Space Flight Center to develop a compact low-power subsystem for spaceflight STAR or FP receiver calibration. We present a common theoretical framework for the design of signals for a controlled correlation calibration source. A statistical model is described, along with temporal and spectral constraints on such signals. Finally, a method for realizing these signals is demonstrated using a Matlab-based implementation.

Kim, Edward J.↗

Common In-Situ Consumable Production Plant for Robotic Mars Exploration

Utilization of extraterrestrial resources, or In-Situ Resource Utilization (ISRU), is viewed by the Human Exploration and Development of Space (HEDS) Enterprise as an enabling technology for the exploration and commercial development of space. A key subset of ISRU which has significant cost, mass, and risk reduction benefits for robotic and human exploration, and which requires a minimum of infrastructure, is In-Situ Consumable Production (ISCP). ISCP involves acquiring, manufacturing, and storing mission consumables from in situ resources, such as propellants, fuel cell reagents, and gases for crew and life support, inflation, science and pneumatic equipment. One of the four long-term goals for the Space Science Enterprise (SSE) is to 'pursue space science programs that enable and are enabled by future human exploration beyond low-Earth orbit - a goal exploiting the synergy with the human exploration of space'. Adequate power and propulsion capabilities are critical for both robotic and human exploration missions. Minimizing the mass and volume of these systems can reduce mission cost or enhance the mission by enabling the incorporation of new science or mission-relevant equipment. Studies have shown that in-situ production of oxygen and methane propellants can enhance sample return missions by enabling larger samples to be returned to Earth or by performing Direct Earth Return (DER) sample return missions instead of requiring a Mars Orbit Rendezvous (MOR). Recent NASA and Department of Energy (DOE) work on oxygen and hydrocarbon-based fuel cell power systems shows the potential of using fuel cell power systems instead of solar arrays and batteries for future rovers and science equipment. The development and use of a common oxygen/methane ISCP plant for propulsion and power generation can extend and enhance the scientific exploration of Mars while supporting the development and demonstration of critical technologies and systems for the human exploration of Mars.

Sanders, G. B.↗

Common-Path Heterodyne Laser-Induced Thermal Acoustics for Seedless Laser Velocimetry

We demonstrate the use of a novel technique for the detection of heterodyne laser-induced thermal acoustics signals, which allows the construction of a highly stable seedless laser velocimeter. A common-path configuration is combined with quadrature detection to provide flow direction, greatly improve robustness to misalignment and vibration, and give reliable velocity measurement at low flow velocities. Comparison with Pitot tube measurements in the freestream of a wind tunnel shows root-mean-square errors of 0.67 m/s over the velocity range 0.55 m/s.

Hart, Roger C.↗

An Investigation Into Criteria Commonly Used by the FAA to Grant Relief to Part 135 Operators Under FAR Sections: 135.213, 135.219, and/or 135.225

The objective of this study was to determine the criteria commonly used by the FAA to grant waivers, exemptions, or deviations to FAR Part 135, Sections 135.213, 135.219, and 135.225 and the potential impact on Flight Information Services Data Link (FISDL) implementation. These aviation regulations address the requirements for the use of weather reports or forecasts when conducting operations under FAR Part 135. In this study a literature search was conducted to obtain historical records of requests for relief from the 3 FAR sections under consideration. The exemption request records were then analyzed in order to determine the reasons given by the FAA for either granting or denying the request. In addition, FAA personnel and Part 135 operators were interviewed to determine the procedures used for satisfying the requirements of the 3 FAR sections.

Williams, Louis J.↗

Orbital Noise in the Earth System is a Common Cause of Climate and Greenhouse-Gas Fluctuation

The mismatch between fossil isotopic data and climate models known as the cool-tropic paradox implies that either the data are flawed or we understand very little about the climate models of greenhouse warming. Here we question the validity of the climate models on the scientific background of orbital noise in the Earth system. Our study shows that the insolation pulsation induced by orbital noise is the common cause of climate change and atmospheric concentrations of carbon dioxide and methane. In addition, we find that the intensity of the insolation pulses is dependent on the latitude of the Earth. Thus, orbital noise is the key to understanding the troubling paradox in climate models.

Liu, H. S.↗

Development of a Flexible Framework of Common Hypersonic Navier-Strokes Meshes for the Space Shuttle Orbiter

A flexible framework for the development of block structured volume grids for hypersonic Navier-Stokes flow simulations was developed for analysis of the Shuttle Orbiter Columbia. The development of the flexible framework, resulted in an ability to quickly generate meshes to directly correlate solutions contributed by participating groups on a common surface mesh, providing confidence for the extension of the envelope of solutions and damage scenarios. The framework draws on the experience of NASA Langely and NASA Ames Research Centers in structured grid generation, and consists of a grid generation process that is implemented through a division of responsibilities. The nominal division of labor consisted of NASA Johnson Space Center coordinating the damage scenarios to be analyzed by the Aerothermodynamics Columbia Accident Investigation (CAI) team, Ames developing the surface grids that described the computational volume about the orbiter, and Langely improving grid quality of Ames generated data and constructing the final volume grids. Distributing the work among the participants in the Aerothermodynamic CIA team resulted in significantly less time required to construct complete meshes than possible by any individual participant. The approach demonstrated that the One-NASA grid generation team could sustain the demand for new meshes to explore new damage scenarios within a aggressive timeline.

Alter, Stephen J.↗