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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 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Ada (R) assessment: An important issue within European Columbus Support Technology Programme

Software will be more important and more critical for Columbus than for any ESA previous project. As a simple comparison, overall software size has been in the range of 100 K source statements for EXOSAT, 500 K for Spacelab, and will probably reach several million lines of code for Columbus (all element together). Based on past experience, the total development cost of software can account for about 10 pct to 15 pct of the total space project development cost. The Ada technology may support the strong software engineering principles needed for Columbus, provided that technology is sufficiently mature and industry plans are meeting the Columbus project schedule. Over the past 3 years, Informatique Internationale has conducted a coherent program based on Ada technology assessment studies and experiments, for ESA and CNES. This specific research and development program benefits from 15 years experience in the field of space software development and is supported by the overall software engineering expertise of the company. The assessment and experiments of Ada software engineering by Informatique Internationale are detailed.

Vielcanet, P.↗
NASA NTRS1988

Programmable pipelined image processor

A pipelined image processor selectively interconnects modules in a column of a two-dimensional array to modules of the next column of the array of modules 1,1 through M,N, where M is the number of modules in one dimension and N is the number of modules in the other direction. Each module includes two input selectors for A and B inputs, two convolvers, a binary function operator, a neighborhood comparison operator which produces an A output and an output selector which may select as a B output the output of any one of the components in the module, including the A output of the neighborhood comparison operator. Each module may be connected to as many as eight modules in the next column, preferably with the majority always in a different row that is up (or down) in the array for a generally spiral data path around the torus thus formed. The binary function operator is implemented as a look-up table addressed by the most significant 8 bits of each 12-bit argument. The table output includes a function value and the slopes for interpolation of the two arguments by multiplying the 4 least significant bits in multipliers and adding the products to the function value through adders.

Donald B Gennery↗
NASA NTRS1987

Motion coordination and programmable teleoperation between two industrial robots

Tasks for two coordinated industrial robots always bring the robots in contact with a same object. The motion coordination among the robots and the object must be maintained all the time. To plan the coordinated tasks, only one robot's motion is planned according to the required motion of the object. The motion of the second robot is to follow the first one as specified by a set of holonomic equality constraints at every time instant. If any modification of the object's motion is needed in real-time, only the first robot's motion has to be modified accordingly in real-time. The modification for the second robot is done implicitly through the constraint conditions. Thus the operation is simplified. If the object is physically removed, the second robot still continually follows the first one through the constraint conditions. If the first robot is maneuvered through either the teach pendant or the keyboard, the second one moves accordingly to form the teleoperation which is linked through the software programming. Obviously, the second robot does not need to duplicate the first robot's motion. The programming of the constraints specifies their relative motions.

Luh, J. Y. S.↗
NASA NTRS1988

Voyager programmability - Experiences in control system adaptation

The two Voyager spacecraft were designed with reprogrammable attitude and articulation control system flight control processors to permit inflight modification of the software. These software modifications were designed to: (1) correct for hardware failures that occurred during the interstellar journey, and (2) improve spacecraft dynamic performance for better control so that, by minimizing the use of propellant, the life of the mission could be extended. It is suggested that, in the future, spacecraft be launched with additional unused memory to deal with anomalies unforeseen in the decision-making process.

Patel, Keyur↗
NASA NTRS1990

Dummy Cup Helps Robot-Welder Programmers

Dummy gas cup used on torch of robotic welder during programming and practice runs. Made of metal or plastic, dummy cup inexpensive and durable. Withstands bumps caused by programming errors, and is sized for special welding jobs within limited clearances. After robot satisfactorily programmed, replaced by ceramic cup of same dimensions for actual welding.

Gordon, Stephen S.↗
NASA NTRS1990

Programmable Remapper

Input image remapped rapidly and accurately onto different coordinate grid. Analog/digital electronic image-processing system developed to warp input images onto arbitrary coordinate grids at video rates. Advantages of system include antialiasing effect of many-to-one data path and speed of lookup-table operation. Lookup tables reprogrammed easily with help of computer that generates table values from mathematical description of desired transformation. Applications include real-time corrections of distortions in input optics of image sensors, corrections for repeatable nonlinear scanning, and aiding persons of impaired vision by deliberately distorting images onto remaining functional portions of retinas.

Juday, Richard D.↗
NASA NTRS1990

Bus-Programmable Slave Card

Slave microprocessors in multimicroprocessor computing system contains modified circuit cards programmed via bus connecting master processor with slave microprocessors. Enables interactive, microprocessor-based, single-loop control. Confers ability to load and run program from master/slave bus, without need for microprocessor development station. Tristate buffers latch all data and information on status. Slave central processing unit never connected directly to bus.

Hall, William A.↗
NASA NTRS1990

Three-Zone Programmable Temperature Controller

Microprocessor-based controller regulates electrical power supplied to heater in each zone of three-zone directional-solidification furnace. Intended primarily for use in microgravity experiments aboard KC-135 airplane, controller also used on ground. Offers advantage of low electrical noise and consequent minimal interference with low-level signals put out by thermocouples and other sensors used in experiments. Achieved by heating with direct (instead of alternating) current and not pulsing heating current.

Smith, Guy A.↗
NASA NTRS1990

Ceramics Analysis and Reliability Evaluation of Structures (CARES). Users and programmers manual

This manual describes how to use the Ceramics Analysis and Reliability Evaluation of Structures (CARES) computer program. The primary function of the code is to calculate the fast fracture reliability or failure probability of macroscopically isotropic ceramic components. These components may be subjected to complex thermomechanical loadings, such as those found in heat engine applications. The program uses results from MSC/NASTRAN or ANSYS finite element analysis programs to evaluate component reliability due to inherent surface and/or volume type flaws. CARES utilizes the Batdorf model and the two-parameter Weibull cumulative distribution function to describe the effect of multiaxial stress states on material strength. The principle of independent action (PIA) and the Weibull normal stress averaging models are also included. Weibull material strength parameters, the Batdorf crack density coefficient, and other related statistical quantities are estimated from four-point bend bar or unifrom uniaxial tensile specimen fracture strength data. Parameter estimation can be performed for single or multiple failure modes by using the least-square analysis or the maximum likelihood method. Kolmogorov-Smirnov and Anderson-Darling goodness-of-fit tests, ninety percent confidence intervals on the Weibull parameters, and Kanofsky-Srinivasan ninety percent confidence band values are also provided. The probabilistic fast-fracture theories used in CARES, along with the input and output for CARES, are described. Example problems to demonstrate various feature of the program are also included. This manual describes the MSC/NASTRAN version of the CARES program.

Nemeth, Noel N.↗
NASA NTRS1990

Programmable, four-channel, 128-sample, 40-Ms/s analog-ternary correlator

A four-channel analog-ternary CCD correlator that extends the state of the art in several important areas is discussed. Surface acoustic wave, acoustic charge transport, and CCD implementation technologies are compared, and the architecture of the CCD device is described. It is shown that, in addition to a sampling rate up to 40 Ms (megasamples) per second, a dynamic range of 66 dB, and nonlinearity below -50 dB, the device exhibits a level of integration and user-friendliness not previously available. The correlator is intended for use in communications and radar systems where pseudonoise codes are employed.

Munroe, Scott C.↗
NASA NTRS1990

Programmable synaptic devices for electronic neural nets

The architecture, design, and operational characteristics of custom VLSI and thin film synaptic devices are described. The devices include CMOS-based synaptic chips containing 1024 reprogrammable synapses with a 6-bit dynamic range, and nonvolatile, write-once, binary synaptic arrays based on memory switching in hydrogenated amorphous silicon films. Their suitability for embodiment of fully parallel and analog neural hardware is discussed. Specifically, a neural network solution to an assignment problem of combinatorial global optimization, implemented in fully parallel hardware using the synaptic chips, is described. The network's ability to provide optimal and near optimal solutions over a time scale of few neuron time constants has been demonstrated and suggests a speedup improvement of several orders of magnitude over conventional search methods.

Moopenn, A.↗
NASA NTRS1990

Ulysses - An ESA/NASA cooperative programme

Cooperation between ESA and NASA is discussed, noting that the Memorandum of Understanding lays the framework for this relationship, defining the responsibilities of ESA and NASA and providing for appointment of leadership and managers for the project. Members of NASA's Jet Propulsion Laboratory and ESA's ESTEC staff have been appointed to leadership positions within the project and ultimate control of the project rests with the Joint Working Group consisting of two project managers and two project scientists, equally representing both organizations. Coordination of time scales and overall mission design is discussed, including launch cooperation, public relations, and funding of scientific investigations such as Ulysses. Practical difficulties of managing an international project are discussed such as differing documentation requirements and communication techniques, and assurance of equality on projects.

Meeks, W.↗
NASA NTRS1990

An AGARD supplemental test programme on the behaviour of short cracks under constant amplitude and aircraft spectrum loading

An AGARD Supplemental Test Program on the growth of short fatigue cracks was conducted to allow testing of various materials and loading conditions that were of interest. Twenty-two participants from ten laboratories in eight countries contributed to the supplemental test program. The objective is to review the supplemental test program and to summarize the results obtained from all laboratories. The materials tested in the supplemental program were: 2024-T3 and 7075-T6 aluminum alloys, 2090-T8E41 aluminum-lithium alloy, Ti6Al4V titanium alloy, and 4340 steel. Tests on single-edge-notch-tension specimens were conducted under several constant-amplitude loading conditions and spectrum loading conditions (FALSTAFF, Inverted FALSTAFF, GAUSSIAN, TWIST, Felix, and the Fokker 100 spectra). The plastic-replica method was used to measure the growth of short cracks at the notch root. The results from the supplemental test program show good agreement among the several laboratories who measured short-crack growth rates on the aluminum-lithium alloy.

Edwards, P. R.↗
NASA NTRS1990

Programmable remapper with single flow architecture

The invention relates to image processing systems and methods and in particular to a machine which accepts a real time video image in the form of a matrix of picture elements (pixels) and remaps such image according to a selectable one of a plurality of mapping functions to create an output matrix of pixels. Such mapping functions, or transformations, may be any one of a number of different transformations depending on the objective of the user of the system. The system remaps input images from one coordinate system to another using a set of look-up tables for the data necessary for the transform. The transforms, which are operator selectable, are precomputed and loaded into massive look-up tables. Input pixels, via the look-up tables of any particular transform selected, are mapped into output pixels with the radiance information of the input pixels being appropriately weighted. An earlier embodiment of the system included two parallel processors: a collective processor which mapped multiple input pixels into a single output pixel and an interpolative processor. The interpolative processor performed an interpolation among pixels in the input image where a given input pixel may affect the value of many output pixels. Several advantages are provided over previous embodiments in that the two distinct processors are replaced by a single processor capable of performing both types of operations (collective and interpolative) with no more complexity. Previously, there has existed no image processor or 'remapper' that can operate with sufficient speed and flexibility to permit investigating different transformation patterns in real time.

Fisher, Timothy E.↗
NASA NTRS1990

Containerless processing in the European microgravity programme

Reasonable acoustic levitation for undercooled melts in space was obtained, but some residual instabilities in times of high thermal transients need to be eliminated. Electrostatic levitation was developed with the acoustic levitator with similar applications in mind. The system tested used a tetrahedral electrode configuration with unchanged samples. ESA's involvement in electromagnetic levitation is concentrated on accommodation studies for the European Containerless Processing Lab for the Space Station Freedom. The gas film technique is based on the processing of samples confined by porous walls. Air flow through the walls create air cushions which inhibit wall contact. This technique is particularly promising for glasses.

Behrmann, P.↗
NASA NTRS1991

Particulate impacts on the UHCRE cosmic ray experiment teflon covers: The ESA programme

The optical scanning equipment at the University of Kent Unit for Space Science consists of a 102.5 by 42.5 cm computer controlled motorized stage which has a reproduction accuracy of 30 microns over the entire area. This is used with an optical microscope connected to two charge coupled device video cameras which can be used to obtain stereo color images of any features found. A coordinate system can be defined on each cover by means of two or more reference marks which allow a feature to be located using different equipment such as a scanning electron microscope, providing two known marks can be found. By using back illumination, penetrating features can be found automatically, and their sizes, circularity, and positions logged for later revisiting either on the optical system or using a scanning electron microscope.

Mcdonnell, J. A. M.↗
NASA NTRS1991

International cooperation in the Space Station programme - Assessing the experience to date

The origins and framework for cooperation in the Space Station program are outlined. Particular attention is paid to issues and commitments between the countries and to the political context of the Station partnership. A number of conclusions concerning international cooperation in space are drawn based on the Space Station experience. Among these conclusions is the assertion that an international partnership requires realistic assesments, mutual trust, and strong commitments in order to work.

Logsdon, John M.↗
NASA NTRS1991

The use of programmable logic controllers (PLC) for rocket engine component testing

Application of PLCs to the rocket engine component testing at a new Stennis Space Center Component Test Facility is suggested as an alternative to dedicated specialized computers. The PLC systems are characterized by rugged design, intuitive software, fault tolerance, flexibility, multiple end device options, networking capability, and built-in diagnostics. A distributed PLC-based system is projected to be used for testing LH2/LOx turbopumps required for the ALS/NLS rocket engines.

Nail, William↗