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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 NTRS1990

Program For Engineering Electrical Connections

DFACS is interactive multiuser computer-aided-engineering software tool for system-level electrical integration and cabling engineering. Purpose of program to provide engineering community with centralized data base for putting in and gaining access to data on functional definition of system, details of end-circuit pinouts in systems and subsystems, and data on wiring harnesses. Objective, to provide instantaneous single point of interchange of information, thus avoiding error-prone, time-consuming, and costly shuttling of data along multiple paths. Designed to operate on DEC VAX mini or micro computer using Version 5.0/03 of INGRES.

Billitti, Joseph W.↗

NASA NTRS1989

Knowledge-based reusable software synthesis system

The Eli system, a knowledge-based reusable software synthesis system, is being developed for NASA Langley under a Phase 2 SBIR contract. Named after Eli Whitney, the inventor of interchangeable parts, Eli assists engineers of large-scale software systems in reusing components while they are composing their software specifications or designs. Eli will identify reuse potential, search for components, select component variants, and synthesize components into the developer's specifications. The Eli project began as a Phase 1 SBIR to define a reusable software synthesis methodology that integrates reusabilityinto the top-down development process and to develop an approach for an expert system to promote and accomplish reuse. The objectives of the Eli Phase 2 work are to integrate advanced technologies to automate the development of reusable components within the context of large system developments, to integrate with user development methodologies without significant changes in method or learning of special languages, and to make reuse the easiest operation to perform. Eli will try to address a number of reuse problems including developing software with reusable components, managing reusable components, identifying reusable components, and transitioning reuse technology. Eli is both a library facility for classifying, storing, and retrieving reusable components and a design environment that emphasizes, encourages, and supports reuse.

Donaldson, Cammie↗

NASA NTRS1989

SSFP approach to software reuse

This talk began by presenting the Space Station Freedom Program (SSFP) definitions of software commonality and software reuse. Software commonality is the use of identical, interchangeable, functionally compatible, or similar software items to satisfy different sets of functionally similar requirements. The Software Support Environment (SSE) and the Data Management System (DMS) of onboard computing facilities are examples of SSFP common software. Software reuse is the use of identical, compatible, or similar software items in either modified or unmodified form to satisfy development activities at any point in the software life cycle; in other words, taking an existing item and applying it to another development activity. Software commonality has been mandated in several critical areas (such as the SSE and DMS) and a policy directive is under review. A software reuse study group was established in May 1988 to gather background information (see Level 2 Software Reuse Study that follows by Scott Herman). The SSFP Program Definition and Requirements Document contains requirements for SSE support in the area of software reuse. The SSE is a collection of tools and rules, and provides the common environment to be used for the life cycle management of all SSFP operational software.

Snyder, Peg↗

NASA NTRS1989

CIS-lunar space infrastructure lunar technologies: Executive summary

Technologies necessary for the creation of a cis-Lunar infrastructure, namely: (1) automation and robotics; (2) life support systems; (3) fluid management; (4) propulsion; and (5) rotating technologies, are explored. The technological focal point is on the development of automated and robotic systems for the implementation of a Lunar Oasis produced by Automation and Robotics (LOAR). Under direction from the NASA Office of Exploration, automation and robotics were extensively utilized as an initiating stage in the return to the Moon. A pair of autonomous rovers, modular in design and built from interchangeable and specialized components, is proposed. Utilizing a buddy system, these rovers will be able to support each other and to enhance their individual capabilities. One rover primarily explores and maps while the second rover tests the feasibility of various materials-processing techniques. The automated missions emphasize availability and potential uses of Lunar resources, and the deployment and operations of the LOAR program. An experimental bio-volume is put into place as the precursor to a Lunar environmentally controlled life support system. The bio-volume will determine the reproduction, growth and production characteristics of various life forms housed on the Lunar surface. Physicochemical regenerative technologies and stored resources will be used to buffer biological disturbances of the bio-volume environment. The in situ Lunar resources will be both tested and used within this bio-volume. Second phase development on the Lunar surface calls for manned operations. Repairs and re-configuration of the initial framework will ensue. An autonomously-initiated manned Lunar oasis can become an essential component of the United States space program.

Faller, W.↗

NASA NTRS1989

Investigation of IGES for CAD/CAE data transfer

In a CAD/CAE facility there is always the possibility that one may want to transfer the design graphics database from the native system to a non-native system. This may occur because of dissimilar systems within an organization or a new CAD/CAE system is to be purchased. The Initial Graphics Exchange Specification (IGES) was developed in an attempt to solve this scenario. IGES is a neutral database format into which the CAD/CAE native database format can be translated to and from. Translating the native design database format to IGES requires a pre-processor and transling from IGES to the native database format requires a post-processor. IGES is an artifice to represent CAD/CAE product data in a neutral environment to allow interfacing applications, archive the database, interchange of product data between dissimilar CAD/CAE systems, and other applications. The intent here is to present test data on translating design product data from a CAD/CAE system to itself and to translate data initially prepared in IGES format to various native design formats. This information can be utilized in planning potential procurement and developing a design discipline within the CAD/CAE community.

Zobrist, George W.↗

NASA NTRS1989

Deceit: A flexible distributed file system

Deceit, a distributed file system (DFS) being developed at Cornell, focuses on flexible file semantics in relation to efficiency, scalability, and reliability. Deceit servers are interchangeable and collectively provide the illusion of a single, large server machine to any clients of the Deceit service. Non-volatile replicas of each file are stored on a subset of the file servers. The user is able to set parameters on a file to achieve different levels of availability, performance, and one-copy serializability. Deceit also supports a file version control mechanism. In contrast with many recent DFS efforts, Deceit can behave like a plain Sun Network File System (NFS) server and can be used by any NFS client without modifying any client software. The current Deceit prototype uses the ISIS Distributed Programming Environment for all communication and process group management, an approach that reduces system complexity and increases system robustness.

Siegel, Alex↗

NASA NTRS1990

Liquid Transfer Cryogenic Test Facility: Initial hydrogen and nitrogen no-vent fill data

The Liquid Transfer Cryogenic Test Facility is a versatile testbed for ground-based cryogenic fluid storage, handling, and transfer experimentation. The test rig contains two well instrumented tanks, and a third interchangeable tank, designed to accommodate liquid nitrogen or liquid hydrogen testing. The internal tank volumes are approx. 18, 5, and 1.2 cu. ft. Tank pressures can be varied from 2 to 30 psia. Preliminary no vent fill tests with nitrogen and hydrogen were successfully completed with the test rig. Initial results indicate that no vent fills of nitrogen above 90 percent full are achievable using this test configuration, in a 1-g environment, and with inlet liquid temperatures as high as 143 R, and an average tank wall temperature of nearly 300 R. This inlet temperature corresponds to a saturation pressure of 19 psia for nitrogen. Hydrogen proved considerably more difficult to transfer between tanks without venting. The highest temperature conditions resulting in a fill level greater than 90 percent were with an inlet liquid temperature of 34 R, and an estimated tank wall temperature of slightly more than 100 R. Saturation pressure for hydrogen at this inlet temperature is 10 psia. All preliminary no vent fill tests were performed with a top mounted full cone nozzle for liquid injection. The nozzle produces a 120 degree conical droplet spray at a differential pressure of 10 psi. Pressure in the receiving tank was held to less than 30 psia for all tests.

Moran, Matthew E.↗

NASA NTRS1990

Design of an autonomous Lunar construction utility vehicle

In order to prepare a site for a manned lunar base, an autonomously operated construction vehicle is necessary. A Lunar Construction Utility Vehicle (LCUV), which utilizes interchangeable construction implements, was designed conceptually. Some elements of the machine were studied in greater detail. Design of an elastic loop track system has advanced to the testing stage. A standard coupling device was designed to insure a proper connection between the different construction tools and the LCUV. Autonomous control of the track drive motors was simulated successfully through the use of a joystick and computer interface. A study of hydrogen-oxygen fuel cells has produced estimates of reactant and product size requirements and identified multi-layer insulation techniques. Research on a 100 kW heat rejection system has determined that it is necessary to house a radiator panel on a utility trailer. The impact of a 720 hr use cycle has produced a very large logistical support lien which requires further study.

Ash, Robert L.↗

NASA NTRS1990

Carbon in the Galaxy: Studies from Earth and Space

Presented here is the text of the invited papers presented during a meeting entitled, Carbon in the Galaxy: Studies from Earth and Space, that was held at NASA Ames Research Center on November 5 and 6, 1987. For completeness, abstracts from all of the poster papers and the text of a paper summarizing what was learned during the course of the meeting are also included. The underlying premise for the meeting was that there is much to be gained by bringing together scientists from very different disciplines, all of whom study carbon in different ways for different reasons. The interchanges took place during the meeting and the contents of the enclosed papers validate that premise.

Tarter, Jill C.↗

NASA NTRS1988

A monochromator based on W/C multilayers of 40 A layer spacing

The design and preliminary performance data are presented for a monochromator based on two multilayer X-ray mirrors. The monochromator is based on mirrors with a d-spacing of 40 A and is designed to operate in the 5-75 A wavelength regime which can be varied by interchanging the mirrors with ones of different d-spacing. The multilayer mirrors are fabricated using sputter deposition and typically consist of 40 layer pairs of W and C. Except for W/Si, which shows 1-2 percent better reflectivities over the 7-40 A range but 4-10 percent poorer reflectivities for wavelengths longer than 40 A and shorter than 7 A, calculations performed using other combinations of materials generally show poorer reflectivities over the wavelength range of interest. Plans for a four-mirror version of the monochromator that will have increased resolution are also presented.

Smith, A.↗

NASA NTRS1989

Facility for interferometric testing of 1.25-m mirrors at liquid helium temperatures

A concept is presented for a national cryogenic optics test facility capable of optical characterization of 1.25 m diameter optics having focal lengths up to 6.2 m at temperatures from 300 K to near 4 K. The facility will be comprised of a large Dewar with a phase shift interferometer, a two-stage vacuum system employing a turbomolecular pump, and an integral vibration isolation system. The entire facility will be housed in a concrete site with a massive floor to assist in reducing vibration during optical tests. By providing interchangeable sections, the overall height of the Dewar can be adjusted to provide for testing of shorter focal length optics. The background for the facility is discussed along with the facility location, and the requirements and the performance considerations which drive the Dewar design with respect to the vibration isolation system, vacuum system, and optical interferometry.

Salerno, Louis J.↗

NASA NTRS1989

Plasma pressure in the environment of Jupiter, inferred from Voyager 1 magnetometer observations

A model combining the internal magnetic field with a self-consistent model of the Jovian magnetodisc was fitted to the Voyager 1 Jovian magnetic field data by means of a generalized inverse technique. The model parameters included the internal field spherical harmonic coefficients as well as with parameters describing the plasma distribution in the magnetosphere. Assuming that the pressure in the middle and outer magnetosphere is related to the unit flux tube volume V through PV exp gamma = const, the model fit yielded a value of 0.88 for gamma. If the hot (30 keV) plasma is transported adiabatically inward under the interchange instability triggered by centrifugal force of the heavy torus ions, losses are not sufficient to account for such a low value of gamma beyond L = 10. Closer to the planet, as the outer edge of the Io plasma torus is approached, PV exp gamma is found to decrease inward, as expected from the particle measurements, which identified an inner boundary of the particle fluxes in that region. With the present stage of the development of magnetodisc models, secular variations of the internal field still remain difficult to estimate.

Caudal, G.↗

NASA NTRS1989

High-resolution near-infrared spectroscopy of water dimer

High-resolution near-infrared spectra are reported for all of the O-H stretch vibrational bands of the water dimer. The four O-H vibrations are characterized as essentially independent proton-donor or proton-acceptor motions. In addition to the rotational and vibrational information contained in these spectra, details are obtained concerning the internal tunneling dynamics in both the ground and excited vibrational states. These results show that, for tunneling motions which involve the interchange of the proton donor and acceptor molecules, the associated frequencies decrease substantially due to vibrational excitation. The predissociation lifetimes for the various states of the dimer are determined from linewidth measurements. These results clearly show that the predissociation dynamics is strongly dependent on the tunneling states, as well as the Ka quantum number, indicating that the internal tunneling dynamics plays an important role in determining the dissociation rate in this complex.

Huang, Z. S.↗

NASA NTRS1990

Transient flux tubes in the terrestrial magnetosphere

Small, isolated density depletions are postulated to be introduced into the magnetotail by an uneven plasma loading process in the far tail. Such bubbles would be displaced earthward by an interchange process, and a significant depletion would move faster than either the gradient-curvature drift speed or the average convection speed. The dissolution of a bubble into the background results in a local reduction in plasma density, thereby violating ideal MHD and the subsequent conservation of plasma content. If a sufficient amount of magnetic flux in the far tail is contained in bubbles, then the net effect may be a reduction of plasma pressure in the near tail sufficient to resolve the pressure balance inconsistency.

Pontius, D. H., Jr.↗

NASA NTRS1990

The kinetics of the Au-InP interaction

An analysis of the reaction of Au and Au-In alloys with InP has permitted the identification of the mechanisms occurring during the first two stages of the Au-InP interaction. The first stage of the interaction, during which the Au is converted to a saturated Au (In) solution, is controlled by the vacancy-generation rate at the free surface of the metallization. The activation energy for this process is the activation energy for Au self-diffusion. Evidence is presented for the existence of large localized variations in this value due to surface related effects. At the completion of stage I stage II becomes active and continues until the metallization is converted to Au3In. This process, proceeding via an interstitial interchange mechanism, is many orders of magnitude slower than stage I. The rate-limiting step, with an activation energy of 2.8 eV, is shown to be the diffusion of In from the InP-metal interface. The P atoms that are released when In enters the metallization during stage I leave the system without reacting, whereas in stage II they form a compound (Au2P3) at the InP-metal interface. The presence of the Au2P3 severely retards the stage II interaction rate.

Fatemi, Navid S.↗

NASA NTRS1990

Data distribution satellite system architecture concept

This paper describes a future communications satellite system architecture concept called the Data Distribution Satellite (DDS). The DDS is envisioned as a new system to be used as an adjunct to TDRS/TDAS for distributing new NASA science data throughout the U.S. as well as internationally. The DDS would also provide networking capability for interchange of science database files among science users and NASA archive depositories. Experimenters would be able to access and control their experimental packages remotely, relieving astronaut workload. This paper gives a conceptual system design based on year 1995 technology. Features of the design include use of Ku and Ka-bands, use of fixed spot beams, 2 Gb/s throughput, and on-board demodulation and switching. The satellite dry mass is 1,300 kg and end-of-life power is 4 kW.

Price, Kent M.↗

NASA NTRS1990

Measured aerodynamic performance of a swept wing with a simulated ice accretion

The effect of a simulated glaze ice accretion on the aerodynamic performance of a three-dimensional swept wing is studied experimentally. A semispan wing of effective aspect ratio four was mounted from a splitter plate in the OSU subsonic wind tunnel. The model uses a NACA 0012 airfoil section on a rectangular planform with interchangeable tip and root pieces to allow for 0- and 30-degree sweep. Surface pressures were measured at 5 semispan locations on the swept-wing model. The section lift data for the 5 semispan locations are presented and compared with theory and zero-sweep model results. In addition, previously unpublished roughness data from the zero-sweep model is presented here. These data show a large drag and maximum lift penalty due to rough simulated glaze ice. The effect of wing-sweep is seen through a decrease in wing lift performance for both the clean and iced wing.

Khodadoust, A.↗

NASA NTRS1990

Mass transport in a neutron star magnetosphere

The interaction between a thin Keplerian accretion disk and a magnetosphere surrounding a central object is investigated within the framework of an analytical description for the magnetic field configuration. The commonly held assumption that all accreting plasma flows from the magnetospheric boundary to the stellar surface is shown to be overly restrictive. If the magnetospheric boundary is defined as the distance where the rotation starts deviating significantly from the Kepler rate, it is found that there is an extensive region inside this boundary where gas, nearly corotating with the star, drifts inward across the field by an interchange instability. The linear analysis of this instability is presented. It is also found that gas tied to field lines can be in equilibrium at positions off the midplane, and that gas can plausibly flow from the midplane to these positions, in certain circumstances. The observational consequences of such a picture are briefly discussed.

Spruit, H. C.↗