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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 1,405 records · Page 78
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NASA NTRS1990

GRID2D/3D: A computer program for generating grid systems in complex-shaped two- and three-dimensional spatial domains. Part 1: Theory and method

An efficient computer program, called GRID2D/3D was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no modifications are needed in the grid generation part of the program. This technical memorandum describes the theory and method used in GRID2D/3D.

Shih, T. I.-P.↗
NASA NTRS1972

A proposed USAF fatigue evaluation program based upon recent systems experience

The United States Air Force has published a document entitled Aircraft Structural Integrity Program. One phase of the program is concerned with the fatigue life certification of all types of military aircraft. The document describes the criteria, analyses, and tests that are necessary in order to satisfy the USAF fatigue life requirement. Some recent and valid criticism has been directed toward the document, particularly the fatigue-life requirements contained in it. Some changes are proposed based on surveys conducted in the United States and abroad as well as some recent systems' experience. The surveys covered both military and civilian organizations. The fatigue certification case histories of selected military and commercial aircraft are presented. The design development element tests, preproduction design verification tests, and full-scale fatigue tests of each are described. A brief status report on the revisions to the MIL-A-008860 series specifications is included.

Haviland, G. P.↗
NASA NTRS1972

ERISTAR: Earth Resources Information Storage, Transformation, Analysis, and Retrieval administrative report

The 1972 Systems Engineering program at Marshall Space Flight Center where 15 participants representing 15 U.S. universities, 1 NASA/MSFC employee, and another specially assigned faculty member, participated in an 11-week program is discussed. The Fellows became acquainted with the philosophy of systems engineering, and as a training exercise, used this approach to produce a conceptional design for an Earth Resources Information Storage, Transformation, Analysis, and Retrieval System. The program was conducted in three phases; approximately 3 weeks were devoted to seminars, tours, and other presentations to subject the participants to technical and other aspects of the information management problem. The second phase, 5 weeks in length, consisted of evaluating alternative solutions to problems, effecting initial trade-offs and performing preliminary design studies and analyses. The last 3 weeks were occupied with final trade-off sessions, final design analyses and preparation of a final report and oral presentation.

Vachon, R. I.↗
NASA NTRS1974

Assess program: Interactive data management systems for airborne research

Two data systems were developed for use in airborne research. Both have distributed intelligence and are programmed for interactive support among computers and with human operators. The C-141 system (ADAMS) performs flight planning and telescope control functions in addition to its primary role of data acquisition; the CV-990 system (ADDAS) performs data management functions in support of many research experiments operating concurrently. Each system is arranged for maximum reliability in the first priority function, precision data acquisition.

Munoz, R. M.↗
NASA NTRS1983

Laboratory system for demonstrating spacecraft processing of multispectral image data

The various elements of the Information Adaptive System (IAS) program are discussed along with the design features, approaches, and algorithms employed within the system. This program was initiated by NASA in order to develop an adaptable data processing system which will accommodate high speed multispectral image data in the real-time spacecraft environment. The development of this system is examined, including the test and support equipment required to evaluate and demonstrate the operational performance of the system in terms of the applicability of the design to high speed onboard processing. In addition to a high throughput rate capability, this system will be flexible, programmable, and capable of adapting its operation to external commands and characteristics of the data stream.

Meredith, B. D.↗
NASA NTRS2017

Numerical Modeling of an Integrated Vehicle Fluids System Loop for Pressurizing a Cryogenic Tank

This paper presents a numerical model of the pressurization loop of the Integrated Vehicle Fluids (IVF) system using the Generalized Fluid System Simulation Program (GFSSP). The IVF propulsion system, being developed by United Launch Alliance to reduce system weight and enhance reliability, uses boiloff propellants to drive thrusters for the reaction control system as well as to run internal combustion engines to develop power and drive compressors to pressurize propellant tanks. NASA Marshall Space Flight Center (MSFC) conducted tests to verify the functioning of the IVF system using a flight-like tank. GFSSP, a finite volume based flow network analysis software developed at MSFC, has been used to support the test program. This paper presents the simulation of three different test series, comparison of numerical prediction and test data and a novel method of presenting data in a dimensionless form. The paper also presents a methodology of implementing a compressor map in a system level code.

LeClair, A. C.↗
NASA NTRS1973

A structurally oriented simulation system

The computer program SOSS (Structurally Oriented Simulation System) is designed to be used as an experimental aid in the study of reliable systems. Basically, SOSS can simulate the structure and behavior of a discrete-time, finite-state, time-invariant system at various levels of structural definition. A general description of the program is given along with its modes of operation, command language of the basic system, future features to be incorporated in SOSS, and an example of usage.

Aran, Z.↗
NASA NTRS1974

Coordinate systems for the space shuttle program

A minimal set of well defined coordinate systems necessary for the interchange of data within the space shuttle program is presented. The document format consists of four parts: (1) a list of the subscripts identifying the coordinate systems, (2) a glossary explaning the terms used within the coordinate system definitions, (3) figures defining, both graphically and verbally, each coordinate system, and (4) an appendix (published separately) showing the relationships (transformations) between similar systems.

Davis, L. D.↗
NASA NTRS2001

Balloon/Parachute to Orbiter Communications Using a Dipole Antenna

Currently, quite a few missions are being studied to send satellites to the outer and inner planets and their moons of the solar system; a large percentage of these missions will have a landed element. NASA's Origins program, Solar System Exploration, Program and Sun Earth Connection (SEC) program, etc., will have a variety of spacecrafts to various solar system planets and their moons to sample and analyze the related atmospheres as well as the soil once the lander lands on the body. These sampling missions may involve a tender element sampling the atmosphere by performing experiments while descending into the atmosphere or a rover collecting samples to return to Earth or a station for experimentation on the planet surface. In either of these cases, the pertinent data generated will have to be sent to the Earth through a communication link. Communications with the Tender during the Entry, Decent and Landing (EDL) phases of a mission is of paramount importance. This article explores a particular method of passing through the atmosphere while communicating with the ground station (DSN station) before landing an instrument package (the lander) on the surface of the planet or moon of interest.

Kantak, Anil V.↗
NASA NTRS1969

VICAR-DIGITAL image processing system

Computer program corrects various photometic, geometric and frequency response distortions in pictures. The program converts pictures to a number of elements, with each elements optical density quantized to a numerical value. The translated picture is recorded on magnetic tape in digital form for subsequent processing and enhancement by computer.

Billingsley, F.↗
NASA NTRS1971

Optimized silicon solar cells for space exploration power systems

A program is described aimed at designing and fabricating improved silicon solar cells for a range of missions extending from 0.1 to 15 astronomical units (Mercury to Jupiter). For missions lying inside Earth radius (Mercury, Venus) the major cell property required was very low series resistance, allowing high curve fill factor to be maintained at the higher intensities. For the Mercury mission, the temperature of the cell had to be kept low. This was achieved by reflecting more of the incident sunlight by use of large area front contacts. For the outer missions (Mars, the Asteroid belts and Jupiter) the formation of a Schottky barrier at the back contact had to be avoided (by use of a P+ layer under the back contact) and the excess leakage current of the PN junction had to be reduced. Optimum grid patterns were also derived and used for these missions.

Iles, P. A.↗