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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 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Human factors technology for America's space program

NASA is initiating a space human factors research and technology development program in October 1982. The impetus for this program stems from: the frequent and economical access to space provided by the Shuttle, the advances in control and display hardware/software made possible through the recent explosion in microelectronics technology, heightened interest in a space station, heightened interest by the military in space operations, and the fact that the technology for long duration stay times for man in space has received relatively little attention since the Apollo and Skylab missions. The rationale for and issues in the five thrusts of the new program are described. The main thrusts are: basic methodology, crew station design, ground control/operations, teleoperations and extra vehicular activity.

Montemerlo, M. D.↗
NASA NTRS1984

Superaugmented rotorcraft program

Concepts, design criteria, and methodology will be examined in four areas: control systems, guidance systems, cockpit dialogue systems, and the integrated intelligence. The approach is to investigate these areas in an individual manner through analysis and simulation and in an integrated manner through simulation and flight. Finally, the integrated concepts will be validated in flight.

Showman, R. D.↗
NASA NTRS1986

A survey of the state of the art and focused research in range systems, task 2

Many communication, control, and information processing subsystems are modeled by linear systems incorporating tapped delay lines (TDL). Such optimized subsystems result in full precision multiplications in the TDL. In order to reduce complexity and cost in a microprocessor implementation, these multiplications can be replaced by single-shift instructions which are equivalent to powers of two multiplications. Since, in general, the obvious operation of rounding the infinite precision TDL coefficients to the nearest powers of two usually yield quite poor system performance, the optimum powers of two coefficient solution was considered. Detailed explanations on the use of branch-and-bound algorithms for finding the optimum powers of two solutions are given. Specific demonstration of this methodology to the design of a linear data equalizer and its implementation in assembly language on a 8080 microprocessor with a 12 bit A/D converter are reported. This simple microprocessor implementation with optimized TDL coefficients achieves a system performance comparable to the optimum linear equalization with full precision multiplications for an input data rate of 300 baud. The philosophy demonstrated in this implementation is dully applicable to many other microprocessor controlled information processing systems.

Yao, K.↗
NASA NTRS1986

Benchmarking hypercube hardware and software

It was long a truism in computer systems design that balanced systems achieve the best performance. Message passing parallel processors are no different. To quantify the balance of a hypercube design, an experimental methodology was developed and the associated suite of benchmarks was applied to several existing hypercubes. The benchmark suite includes tests of both processor speed in the absence of internode communication and message transmission speed as a function of communication patterns.

Grunwald, Dirk C.↗
NASA NTRS1988

A flight-test methodology for identification of an aerodynamic model for a V/STOL aircraft

Described is a flight test methodology for developing a data base to be used to identify an aerodynamic model of a vertical and short takeoff and landing (V/STOL) fighter aircraft. The aircraft serves as a test bed at Ames for ongoing research in advanced V/STOL control and display concepts. The flight envelope to be modeled includes hover, transition to conventional flight, and back to hover, STOL operation, and normaL cruise. Although the aerodynamic model is highly nonlinear, it has been formulated to be linear in the parameters to be identified. Motivation for the flight test methodology advocated in this paper is based on the choice of a linear least-squares method for model identification. The paper covers elements of the methodology from maneuver design to the completed data base. Major emphasis is placed on the use of state estimation with tracking data to ensure consistency among maneuver variables prior to their entry into the data base. The design and processing of a typical maneuver is illustrated.

Bach, Ralph E., Jr.↗
NASA NTRS1986

The RP-2 sailplane

The all-composite design and fabrication methodology employed by Rensselaer Polytechnic Intitute's 'CAPGLIDE' program in producing such sailplanes as the RP-2 is discussed. The RP-2's production methods, which furnish hands-on experience for the students enrolled in the program, encompass wet lay-up and vacuum bag procedures, as well as autoclave curing of prepreg parts employing graphite, kevlar, and glass fiber reinforcements. Epoxy resins are the primary matrix materials, and are used in conjunction with polymer foams for the sandwich panel elements of the sailplane structure.

Winckler, Steven↗
NASA NTRS1988

Dragging down fuel costs

It has been suggested that modest reductions in friction drag could save U.S. airlines $200-500 million a year. Potentially significant fuel savings are to be expected from laminar flow control (LFC) with suction surfaces on a CTOL subsonic transport; fuel savings from 25 to 40 percent are possible, depending on stage length. NASA has developed advanced computational design tools and methodology, subsonic and transonic NLF (natural laminar flow) and LFC airfoils, practical laminar wing construction techniques, and practical leading-edge treatments applicable to civil and military transports. It is concluded that skin-friction and induced drag approaches can combine to make a 50 percent reduction a reality for commercial and military aircraft of the future.

Hefner, Jerry N.↗
NASA NTRS1989

An approximate methods approach to probabilistic structural analysis

A probabilistic structural analysis method (PSAM) is described which makes an approximate calculation of the structural response of a system, including the associated probabilistic distributions, with minimal computation time and cost, based on a simplified representation of the geometry, loads, and material. The method employs the fast probability integration (FPI) algorithm of Wu and Wirsching. Typical solution strategies are illustrated by formulations for a representative critical component chosen from the Space Shuttle Main Engine (SSME) as part of a major NASA-sponsored program on PSAM. Typical results are presented to demonstrate the role of the methodology in engineering design and analysis.

Mcclung, R. C.↗
NASA NTRS1989

Parkes radio science system design and testing for Voyager Neptune encounter

The Radio Science System installed at Parkes, Australia for the Voyager Neptune encounter was specified to meet the same stringent requirements that were imposed upon the Deep Space Network Radio Science System. The system design and test methodology employed to meet these requirements at Parkes are described, and data showing the measured performance of the system are presented. The results indicate that the system operates with a comfortable margin on the requirements. There was a minor problem with frequency-dependent spurious signals which could not be fixed before the encounter. Test results characterizing these spurious signals are included.

Rebold, T. A.↗
NASA NTRS1989

A flight-test methodology for identification of an aerodynamic model for a V/STOL aircraft

This paper describes a flight-test methodology for developing a data base to be used to identify an aerodynamic model of a V/STOL fighter aircraft. The aircraft serves as a test bed at NASA Ames for ongoing research in advanced V/STOL control and display concepts. The flight envelope to be modeled includes hover, transition to conventional flight and back to hover, STOL operation, and normal cruise. Although the aerodynamic model is highly nonlinear, it has been formulated to be linear in the parameters to be identified. Motivation for the flight-test methodology advocated in this paper is based on the choice of a linear least-squares method for model identification. The paper covers elements of the methodology from maneuver design to the completed data base. Major emphasis is placed on the use of state estimation with tracking data to ensure consistency among maneuver variables prior to their entry into the data base. The design and processing of a typical maneuver are illustrated.

Bach, R. E., Jr.↗
NASA NTRS1989

The International Cometary Explorer comet encounter and earth-return trajectory

ICE experienced a successful encounter with Comet Giacobini-Zinner on September 11, 1985. The comet-intercept trajectory, earth-return trajectory, and two cases of a possible 2014 capture trajectory are presented. Also, the essential propulsive trajectory correction maneuvers and the projected August 10, 2014 lunar swingby maneuver are discussed. The targeting methodology used for designing the trajectories is also discussed.

Roberts, Craig E.↗
NASA NTRS1990

Hypersonic vehicle simulation model: Winged-cone configuration

Aerodynamic, propulsion, and mass models for a generic, horizontal-takeoff, single-stage-to-orbit (SSTO) configuration are presented which are suitable for use in point mass as well as batch and real-time six degree-of-freedom simulations. The simulations can be used to investigate ascent performance issues and to allow research, refinement, and evaluation of integrated guidance/flight/propulsion/thermal control systems, design concepts, and methodologies for SSTO missions. Aerodynamic force and moment coefficients are given as functions of angle of attack, Mach number, and control surface deflections. The model data were estimated by using a subsonic/supersonic panel code and a hypersonic local surface inclination code. Thrust coefficient and engine specific impulse were estimated using a two-dimensional forebody, inlet, nozzle code and a one-dimensional combustor code and are given as functions of Mach number, dynamic pressure, and fuel equivalence ratio. Rigid-body mass moments of inertia and center of gravity location are functions of vehicle weight which is in turn a function of fuel flow.

Shaughnessy, John D.↗
NASA NTRS1992

A status of the activities of the NASA/MSFC pump stage technology team

The Consortium for Computational Fluid Dynamics (CFD) Application in Propulsion Technology was established to aid the transfer of CFD related advancements among academia, government agencies, and industry. The specific goals of the Consortium are to develop CFD methodologies necessary to solve propulsion problems, to validate these methodologies, and to apply these methodologies in the design process. To accomplish these goals, a team of experts in various related fields was formed, a schedule of activities necessary to meet the goals was generated, and funding for the activities was obtained from NASA. During the past year (Mar. 1991 - Mar. 1992) the team's activities have focused on preliminary code validation and on the design of an advanced impeller. Six codes were used to calculate the flow in a Rocketdyne 0.3 flow coefficient inducer, and the results were compared to L2F data available for the inducer. This activity identified shortcomings in the experimental data sets and in the analytical solutions which must be surmounted in any future team activity. The design of the advanced impeller relied heavily on CFD results to obtain an optimized geometry. The optimized geometry was analyzed using four different codes, at design and off-design conditions. Activities for the next year include the optimization of a tandem blade impeller design, benchmark of CFD codes for diffuser and volute flows, the collection of L2F data for 'state-of-the-art' impeller and inducer, and the verification of the advanced pump team impeller design in a water rig.

Garcia, R.↗
NASA NTRS1991

Dynamics of free drops on USML-1

Drop-dynamics experiments are described in terms of scope and methodology that are designed for the USML-1 flight. Included are experiments regarding: (1) the equilibrium shapes of acoustically rotated drops; (2) large-amplitude drop and bubble-shape oscillations; (3) the collision and coalescence of free drops; and (4) the deformation and instability of levitated drops. The space flight is concluded to provide an effective containerless microgravity environment for studying linear and nonlinear dynamics.

Wang, Taylor G.↗
NASA NTRS1991

NASA CSTI Earth-to-orbit propulsion R/T program overview

The topics presented are covered in viewgraph form. The programmatic objectives are to develop and validate technology, design tools, and methodologies needed for the development of a new generation of lower cost, operationally-efficient, long-life, highly reliable ETO propulsion systems. The technical objectives are: (1) high quality, low cost, inspectable manufacturing; (2) safe shutdown to fault tolerance operations for safety; (3) condition monitoring diagnostics for maintainability; (4) automatic servicing and checkout for ground operations; (5) max commensurate with life for performance; and full flow, combined cycle for advanced cycles.

Moses, James L.↗
NASA NTRS1991

Low-cost commercial transport

The topics presented are covered in viewgraph form. The objectives are to develop and validate technology, design tools and methodologies to enable the low cost commercial development and operational uses of hydrogen and hydrocarbon fueled liquid engines, low pressure booster engines and hybrid engines.

Mcpherson, J.↗
NASA NTRS1991

New technology and regional studies in human ecology: A Papua New Guinea example

Two key issues in using technologies such as digital image processing and geographic information systems are a conceptually and methodologically valid research design and the exploitation of varied sources of data. With this realized, the new technologies offer anthropologists the opportunity to test hypotheses about spatial and temporal variations in the features of interest within a regionally coherent mosaic of social groups and landscapes. Current research on the Mountain OK of Papua New Guinea is described with reference to these issues.

Morren, George E. B., Jr.↗
NASA NTRS1996

Cyclic Load Effects on Long Term Behavior of Polymer Matrix Composites

A methodology to compute the fatigue life for different ratios, r, of applied stress to the laminate strength based on first ply failure criteria combined with thermal cyclic loads has been developed and demonstrated. Degradation effects resulting from long term environmental exposure and thermo-mechanical cyclic loads are considered in the simulation process. A unified time-stress dependent multi-factor interaction equation model developed at NASA Lewis Research Center has been used to account for the degradation of material properties caused by cyclic and aging loads. Effect of variation in the thermal cyclic load amplitude on a quasi-symmetric graphite/epoxy laminate has been studied with respect to the impending failure modes. The results show that, for the laminate under consideration, the fatigue life under combined mechanical and low thermal amplitude cyclic loads is higher than that due to mechanical loads only. However, as the thermal amplitude increases, the life also decreases. The failure mode changes from tensile under mechanical loads only to the compressive and shear at high mechanical and thermal loads. Also, implementation of the developed methodology in the design process has been discussed.

Shah, A. R.↗