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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

The Path to Interferometry in Space

For over two decades, astronomers have considered the possibilities for interferometry in space. The first of these missions was the Space Interferometry Mission (SIM), but that was followed by missions for studying exoplanets (e.g Terrestrial Planet Finder, Darwin), and then far-infrared interferometers (e.g. the Space Infrared Interferometric Telescope, the Far-Infrared Interferometer). Unfortunately, following the cancellation of SIM, the future for space-based interferometry has been in doubt, and the interferometric community needs to reevaluate the path forward. While interferometers have strong potential for scientific discovery, there are technological developments still needed, and continued maturation of techniques is important for advocacy to the broader astronomical community. We review the status of several concepts for space-based interferometry, and look for possible synergies between missions oriented towards different science goals.

Rinehart, S. A.↗
NASA NTRSDate not supplied

Development of Head-Trunk Coordination Measures for Monitoring Postflight Sensorimotor Readaptation Strategies

During exploration missions, individual health assessments will be required to account for variability in neurosensory adaptation and task readiness for the initial extravehicular activities (EVAs). Previous research has identified postflight vestibular alterations and disruptions in head-trunk coordination after both short and long duration spaceflight missions. Astronauts were found to minimize head angular displacement and utilize a consistent forward head tilt theorized as a compensatory approach to stabilize the cephalic system and reduce motion sickness during readaptation to Earth’s gravity. Further, anecdotal self-reports from Shuttle crewmembers stated that pitch and side-to-side head movements immediately post-landing typically resulted in perceived angular self-motion. Notable disruptions also occur upon arrival in orbit, with astronauts choosing waist rotation rather than head movements during dynamic tasks. It is thought that the underlying sensorimotor disruptions may contribute to motion sickness in space and upon landing, postflight gait dysfunction, and inaccurate spatial orientation when performing daily tasks. To better characterize microgravity-induced sensorimotor adaptations, it is important to develop measures and monitoring tools that have high sensitivity in detecting changes in head-trunk coordination.

H M Weiss↗
NASA NTRS1981

Vestibular experiments

Spacelab experiments designed to investigate space motion sickness, any associated changes in otolith-mediated responses occurring during weightlessness, and the carryover of any such changes to postflight conditions are described. The experiments aimed at assessing otolithic responses in space are intended to clarify presumed alterations in vestibular function during weightlessness. Vestibular function will be investigated at several levels: vestibulo-ocular reflexes, vestibulo-spinal pathways, cortical functions involving perception of motion and spatial orientation, visual vestibular interaction, and motion sickness susceptibility. A second major objective relates to space motion sickness and man's well-being and productivity in space.

Young, L. R.↗
NASA NTRS2006

Using Light Curves to Characterize Size and Shape of Pseudo-Debris

Photometric measurements were collected for a new study aimed at estimating orbital debris sizes based on object brightness. To obtain a size from optical measurements the current practice is to assume an albedo and use a normalized magnitude to calculate optical size. However, assuming a single albedo value may not be valid for all objects or orbit types; material type and orientation can mask an object s true optical cross section. This experiment used a CCD camera to record data, a 300 W Xenon, Ozone Free collimated light source to simulate solar illumination, and a robotic arm with five degrees of freedom to move the piece of simulated debris through various orientations. The pseudo-debris pieces used in this experiment originate from the European Space Operations Centre s ESOC2 ground test explosion of a mock satellite. A uniformly illuminated white ping-pong ball was used as a zero-magnitude reference. Each debris piece was then moved through specific orientations and rotations to generate a light curve. This paper discusses the results of five different object-based light curves as measured through an x-rotation. Intensity measurements, from which each light curve was generated, were recorded in five degree increments from zero to 180 degrees. Comparing light curves of different shaped and sized pieces against their characteristic length establishes the start of a database from which an optical size estimation model will be derived in the future.

Rodriquez, Heather M.↗
NASA NTRS1990

Object-oriented fault tree models applied to system diagnosis

When a diagnosis system is used in a dynamic environment, such as the distributed computer system planned for use on Space Station Freedom, it must execute quickly and its knowledge base must be easily updated. Representing system knowledge as object-oriented augmented fault trees provides both features. The diagnosis system described here is based on the failure cause identification process of the diagnostic system described by Narayanan and Viswanadham. Their system has been enhanced in this implementation by replacing the knowledge base of if-then rules with an object-oriented fault tree representation. This allows the system to perform its task much faster and facilitates dynamic updating of the knowledge base in a changing diagnosis environment. Accessing the information contained in the objects is more efficient than performing a lookup operation on an indexed rule base. Additionally, the object-oriented fault trees can be easily updated to represent current system status. This paper describes the fault tree representation, the diagnosis algorithm extensions, and an example application of this system. Comparisons are made between the object-oriented fault tree knowledge structure solution and one implementation of a rule-based solution. Plans for future work on this system are also discussed.

Iverson, David L.↗
NASA NTRS2013

Background Oriented Schlieren (BOS) and other Flow Visualization Developments and Applications at GRC

This is a presentation to be given at an internal NASA Advanced Schlieren Working Group Meeting. The presentation will cover the recent developments and applications of flow visualization methods at GRC. The topics being discussed will include the use of Background Oriented Schlieren (BOS) in the study of screech and its associated shock spacing as well as in the investigation of broadband shock noise reduction in the Jet-Surface Interaction Tests. In addition, other flow visualiztion methods will be discussed in an on-going study comparing schlieren, shadowgraph, BOS, and focusing schlieren.

background oriented schlieren↗
NASA NTRS1991

Using semantic data modeling techniques to organize an object-oriented database for extending the mass storage model

A methodology for optimizing organization of data obtained by NASA earth and space missions is discussed. The methodology uses a concept based on semantic data modeling techniques implemented in a hierarchical storage model. The modeling is used to organize objects in mass storage devices, relational database systems, and object-oriented databases. The semantic data modeling at the metadata record level is examined, including the simulation of a knowledge base and semantic metadata storage issues. The semantic data model hierarchy and its application for efficient data storage is addressed, as is the mapping of the application structure to the mass storage.

Campbell, William J.↗
NASA NTRS2013

Silicon Heat Pipe Array

Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better suited for the cooling of semiconductor devices.

Yee, Karl Y.↗
NASA NTRS1993

Characterization of a space orbited incoherent fiber optic bundle

The results of a study performed to determine the effects of adverse space environments on a bundle of over 1800 optical fibers orbited for 69 months are reported. Experimental results are presented on an incoherent fiber optic bundle oriented in low Earth orbit aboard the Long Duration Exposure Facility (LDEF) satellite as part of the Space Environment Effects Experiment (M0006). Measurements were performed to determine if space induced radiation effects changed the fiber bundle characteristics. Data demonstrating the success of light transmitting fibers to withstand the adverse space environment are presented.

Dewalt, Stephen A.↗
DOE OSTI2024

Self-consistent solution of the Frank–Bilby equation for interfaces containing disconnections

The quantized Frank–Bilby equation can be used to identify interfacial line defect array configurations which relax the misorientation and/or misfit of a coherent crystalline interface. These line defect arrays may be comprised of dislocations and/or disconnections, which are interfacial steps with dislocation character. When an interface contains disconnections, solution of the quantized Frank–Bilby equation is complicated by the fact that the habit plane orientation is not known in advance because it depends on the unknown spacing of the disconnection array. We present a root-finding-based method for addressing this issue, enabling a self-consistent solution for arbitrary defect content. Our method has been implemented in an open-source code which enumerates all possible solutions given a list of candidate line defects. Two cases are presented employing the code: a misoriented FCC twin boundary and an FCC/BCC phase boundary with the Nishiyama-Wasserman orientation relationship. Both cases exhibit more than 10,000 solutions to the Frank–Bilby equation, with several hundred solutions categorized as ‘‘low energy’’ and thus plausible configurations for the actual interface. The resulting set of solutions can be utilized to predict and understand the properties of a given interface.

42 ENGINEERING↗
NASA NTRSDate not supplied

Analysis of the Amplitude Response of a Two-Point and a Multi-Point Focused Laser Differential Interferometer

Experiments were performed with two different focused laser differential interferometer (FLDI) instruments to assess the relative amplitude response of each instrument to a traveling shockwave generated by a laser spark in air. The first FLDI instrument generated two slightly-separated measurement points, with each measurement point providing sensitivity to density fluctuations induced by the shockwave. By performing a cross-correlation between the signals obtained from each measurement point, the phase velocity of density fluctuations can be obtained. The second FLDI instrument generated a measurement line that was oriented parallel to the shockwave direction of travel with the resulting interference pattern sampled at multiple equally-spaced points along the line. As a result, this instrument provides density fluctuation measurement capability at multiple points simultaneously. When the measurement line is oriented parallel to the shockwave direction of travel, the phase velocity, rate of change of the phase velocity, and acceleration of density fluctuations traveling along each line can be obtained by performing a cross-correlation between points along the line. Numerical computations of the shockwave generated by the laser spark are used to simulate the response of each instrument and are compared to the experimental results. High-speed schlieren imaging has also been performed and is compared with the FLDI measurements and computational results.

Brett F. Bathel↗
NASA NTRSDate not supplied

Analysis of the Amplitude Response of a Two-Point and a Multi-Point Focused Laser Differential Interferometer

Experiments were performed with two different focused laser differential interferometer (FLDI) instruments to assess the relative amplitude response of each instrument to a traveling shockwave generated by a laser spark in air. The first FLDI instrument generated two slightly-separated measurement points, with each measurement point providing sensitivity to density fluctuations induced by the shockwave. By performing a cross-correlation between the signals obtained from each measurement point, the phase velocity of density fluctuations can be obtained. The second FLDI instrument generated a measurement line that was oriented parallel to the shockwave direction of travel with the resulting interference pattern sampled at multiple equally-spaced points along the line. As a result, this instrument provides density fluctuation measurement capability at multiple points simultaneously. When the measurement line is oriented parallel to the shockwave direction of travel, the phase velocity, rate of change of the phase velocity, and acceleration of density fluctuations traveling along each line can be obtained by performing a cross-correlation between points along the line. Numerical computations of the shockwave generated by the laser spark are used to simulate the response of each instrument and are compared to the experimental results. High-speed schlieren imaging has also been performed and is compared with the FLDI measurements and computational results.

Interferometry↗
DOE OSTI2026

One-dimensional neutron diffraction from layered graphite: Reciprocal space structure and grating behavior

In this work we report observations of one-dimensional neutron diffraction from highly oriented pyrolytic graphite (HOPG), where the scattering angle varies continuously with incident angle following classical grating-like behavior. The 2D polycrystalline structure of HOPG—with highly aligned layers along the 𝑐 axis but random in-plane rotations—creates planes of scattering intensity in reciprocal space at 𝑄 𝑐 =𝑛⁢(2⁢𝜋/𝑑) where 𝑑=3.35Å is the interlayer spacing. As the Ewald sphere sweeps through reciprocal space during sample rotation, it continuously intersects these planes, producing the observed angular dispersion. We observe both first-order (𝑛=1) and second-order (𝑛=2) diffraction at conventional scattering angles (25°–70°), with peak positions that remain temperature-independent between 10 K and 294 K and follow quantitative agreement with momentum conservation 𝑄 𝑐 =𝑘⁢[sin⁡𝜓−sin⁡𝜓 𝑓 ]=𝑛⁢(2⁢𝜋/𝑑). X-ray diffraction under similar conditions shows no comparable behavior, confirming that sharp nuclear-vacuum contrast is essential. While diffraction intensities are weak (∼10 −6 of Bragg peaks), the observations demonstrate how the interplay of atomic-scale periodicity, nuclear contrast, and structural disorder enables observation of continuous diffraction curves at thermal neutron wavelengths, illustrating how HOPG's unique microstructure determines its scattering properties beyond conventional Bragg diffraction.

2-dimensional systems↗
NASA NTRS1974

Vectorcardiographic results from Skylab medical experiment M092: Lower body negative pressure

Vectorcardiograms were recorded via a modified Frank lead system from all crewmen of the three Skylab missions in conjuction with the Lower Body Negative Pressure - M092 Experiment. Data were analyzed by a specially developed computer program (VECTAN). Design of the test sequences allowed direct comparisons of supine resting, Earth based (reference) vectorcardiograms with those taken during lower body negative pressure stress and those obtained at rest in orbit, as well as combinations of these conditions. Results revealed several statistically significant space flight related changes; namely, increased testing and lower body negative pressure stressed heart rates, modestly increased PR interval and corrected QTC interval, and greatly increased P and QPS loop maximal amplitudes. In addition, orientation changes in the QRS maximum vector and the J-vector at rest in space seem quite consistent among crewmen and different from those caused by the application of lower body negative pressure. No clinical abnormalities were observed. Etiology of these findings is conjectured to be, at least in part, related to fluid mass shifts occurring in weightlessness and attendant alterations in cardiovascular dynamics and myocardial autonomic control mechanisms.

Hoffler, G. W.↗
NASA NTRS2007

Sensor Webs with a Service-Oriented Architecture for On-demand Science Products

This paper describes the work being managed by the NASA Goddard Space Flight Center (GSFC) Information System Division (ISD) under a NASA Earth Science Technology Ofice (ESTO) Advanced Information System Technology (AIST) grant to develop a modular sensor web architecture which enables discovery of sensors and workflows that can create customized science via a high-level service-oriented architecture based on Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) web service standards. These capabilities serve as a prototype to a user-centric architecture for Global Earth Observing System of Systems (GEOSS). This work builds and extends previous sensor web efforts conducted at NASA/GSFC using the Earth Observing 1 (EO-1) satellite and other low-earth orbiting satellites.

Mandl, Daniel↗
NASA NTRS2008

An Object-oriented Computer Code for Aircraft Engine Weight Estimation

Reliable engine-weight estimation at the conceptual design stage is critical to the development of new aircraft engines. It helps to identify the best engine concept amongst several candidates. At NASA Glenn (GRC), the Weight Analysis of Turbine Engines (WATE) computer code, originally developed by Boeing Aircraft, has been used to estimate the engine weight of various conceptual engine designs. The code, written in FORTRAN, was originally developed for NASA in 1979. Since then, substantial improvements have been made to the code to improve the weight calculations for most of the engine components. Most recently, to improve the maintainability and extensibility of WATE, the FORTRAN code has been converted into an object-oriented version. The conversion was done within the NASA s NPSS (Numerical Propulsion System Simulation) framework. This enables WATE to interact seamlessly with the thermodynamic cycle model which provides component flow data such as airflows, temperatures, and pressures, etc. that are required for sizing the components and weight calculations. The tighter integration between the NPSS and WATE would greatly enhance system-level analysis and optimization capabilities. It also would facilitate the enhancement of the WATE code for next-generation aircraft and space propulsion systems. In this paper, the architecture of the object-oriented WATE code (or WATE++) is described. Both the FORTRAN and object-oriented versions of the code are employed to compute the dimensions and weight of a 300- passenger aircraft engine (GE90 class). Both versions of the code produce essentially identical results as should be the case. Keywords: NASA, aircraft engine, weight, object-oriented

Tong, Michael T.↗
NASA NTRS2009

An Object-Oriented Computer Code for Aircraft Engine Weight Estimation

Reliable engine-weight estimation at the conceptual design stage is critical to the development of new aircraft engines. It helps to identify the best engine concept amongst several candidates. At NASA Glenn Research Center (GRC), the Weight Analysis of Turbine Engines (WATE) computer code, originally developed by Boeing Aircraft, has been used to estimate the engine weight of various conceptual engine designs. The code, written in FORTRAN, was originally developed for NASA in 1979. Since then, substantial improvements have been made to the code to improve the weight calculations for most of the engine components. Most recently, to improve the maintainability and extensibility of WATE, the FORTRAN code has been converted into an object-oriented version. The conversion was done within the NASA's NPSS (Numerical Propulsion System Simulation) framework. This enables WATE to interact seamlessly with the thermodynamic cycle model which provides component flow data such as airflows, temperatures, and pressures, etc., that are required for sizing the components and weight calculations. The tighter integration between the NPSS and WATE would greatly enhance system-level analysis and optimization capabilities. It also would facilitate the enhancement of the WATE code for next-generation aircraft and space propulsion systems. In this paper, the architecture of the object-oriented WATE code (or WATE++) is described. Both the FORTRAN and object-oriented versions of the code are employed to compute the dimensions and weight of a 300-passenger aircraft engine (GE90 class). Both versions of the code produce essentially identical results as should be the case.

Tong, Michael T.↗