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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

A Knowledge-Based Approach to Configuration Layout, Justification, and Documentation

The design, development, and implementation of a prototype expert system which could aid designers and system engineers in the placement of racks aboard modules on the Space Station Freedom are described. This type of problem is relevant to any program with multiple constraints and requirements demanding solutions which minimize usage of limited resources. This process is generally performed by a single, highly experienced engineer who integrates all the diverse mission requirements and limitations, and develops an overall technical solution which meets program and system requirements with minimal cost, weight, volume, power, etc. This system architect performs an intellectual integration process in which the underlying design rationale is often not fully documented. This is a situation which lends itself to an expert system solution for enhanced consistency, thoroughness, documentation, and change assessment capabilities.

Craig, F. G.↗
NASA NTRS1991

Neurocontrol and fuzzy logic: Connections and designs

Artificial neural networks (ANNs) and fuzzy logic are complementary technologies. ANNs extract information from systems to be learned or controlled, while fuzzy techniques mainly use verbal information from experts. Ideally, both sources of information should be combined. For example, one can learn rules in a hybrid fashion, and then calibrate them for better whole-system performance. ANNs offer universal approximation theorems, pedagogical advantages, very high-throughput hardware, and links to neurophysiology. Neurocontrol - the use of ANNs to directly control motors or actuators, etc. - uses five generalized designs, related to control theory, which can work on fuzzy logic systems as well as ANNs. These designs can copy what experts do instead of what they say, learn to track trajectories, generalize adaptive control, and maximize performance or minimize cost over time, even in noisy environments. Design tradeoffs and future directions are discussed throughout.

Werbos, Paul J.↗
NASA NTRS1990

Robotic lunar surface operations: Engineering analysis for the design, emplacement, checkout and performance of robotic lunar surface systems

The assembly, emplacement, checkout, operation, and maintenance of equipment on planetary surfaces are all part of expanding human presence out into the solar system. A single point design, a reference scenario, is presented for lunar base operations. An initial base, barely more than an output, which starts from nothing but then quickly grows to sustain people and produce rocket propellant. The study blended three efforts: conceptual design of all required surface systems; assessments of contemporary developments in robotics; and quantitative analyses of machine and human tasks, delivery and work schedules, and equipment reliability. What emerged was a new, integrated understanding of hot to make a lunar base happen. The overall goal of the concept developed was to maximize return, while minimizing cost and risk. The base concept uses solar power. Its primary industry is the production of liquid oxygen for propellant, which it extracts from native lunar regolith. Production supports four lander flights per year, and shuts down during the lunar nighttime while maintenance is performed.

Woodcock, Gordon R.↗
NASA NTRS1992

Candidate Mission from Planet Earth control and data delivery system architecture

Using a structured, experienced-based approach, Goddard Space Flight Center (GSFC) has assessed the generic functional requirements for a lunar mission control and data delivery (CDD) system. This analysis was based on lunar mission requirements outlined in GSFC-developed user traffic models. The CDD system will facilitate data transportation among user elements, element operations, and user teams by providing functions such as data management, fault isolation, fault correction, and link acquisition. The CDD system for the lunar missions must not only satisfy lunar requirements but also facilitate and provide early development of data system technologies for Mars. Reuse and evolution of existing data systems can help to maximize system reliability and minimize cost. This paper presents a set of existing and currently planned NASA data systems that provide the basic functionality. Reuse of such systems can have an impact on mission design and significantly reduce CDD and other system development costs.

Shapiro, Phillip↗
NASA NTRS1993

Improved Nystrom Integrators

New formulation for Nystrom integrators offers increased precision and speed of computation. Formulation takes advantage of capabilities of modern electronic computers. Independent and dependent variables and various partial and total derivatives expressed via compact tensor notation. In this approach, typical set of constraint equations derived in about 1 day. Solution of constraint equations speeded by SEARCH computer program. Is general-purpose optimization program, which maximizes or minimizes cost function defined by user. Used successfully, to make least-squares fit of about 4,000 equations in 12 unknowns.

Lear, William M.↗
NASA NTRS1992

MM-122: High speed civil transport

The rapidly expanding Pacific Rim market along with other growing markets indicates that the future market potential for a high speed civil transport is great indeed. The MM-122 is the answer to the international market desire for a state of the art, long range, high speed civil transport. It will carry 250 passengers a distance of 5200 nm at over twice the speed of sound. The MM-122 is designed to incorporate the latest technologies in the areas of control systems, propulsions, aerodynamics, and materials. The MM-122 will accomplish these goals using the following design parameters. First, a double delta wing planform with highly swept canards and an appropriately area ruled fuselage will be incorporated to accomplish desired aerodynamic characteristics. Propulsion will be provided by four low bypass variable cycle turbofan engines. A quad-redundant fly-by-wire flight control system will be incorporated to provide appropriate static stability and level 1 handling qualities. Finally, the latest in conventional metallic and modern composite materials will be used to provide desired weight and performance characteristics. The MM-122 incorporates the latest in technology and cost minimization techniques to provide a viable solution to this future market potential.

Demarest, Bill↗
NASA NTRS1993

Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS)

This effort involves development of a calibrated, pulsed coherent CO2 Doppler lidar, followed by a carefully-planned and -executed program of multi-dimensional wind velocity and aerosol backscatter measurements from the NASA DC-8 research aircraft. The lidar, designated as the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS), will be applicable to two research areas. First, MACAWS will enable specialized measurements of atmospheric dynamical processes in the planetary boundary layer and free troposphere in geographic locations and over scales of motion not routinely or easily accessible to conventional sensors. The proposed observations will contribute fundamentally to a greater understanding of the role of the mesoscale, helping to improve predictive capabilities for mesoscale phenomena and to provide insights into improving model parameterizations of sub-grid scale processes within large-scale circulation models. As such, it has the potential to contribute uniquely to major, multi-institutional field programs planned for the mid 1990's. Second, MACAWS measurements can be used to reduce the degree of uncertainty in performance assessments and algorithm development for NASA's prospective Laser Atmospheric Wind Sounder (LAWS), which has no space-based instrument heritage. Ground-based lidar measurements alone are insufficient to address all of the key issues. To minimize costs, MACAWS is being developed cooperatively by the lidar remote sensing groups of the Jet Propulsion Laboratory, NOAA Wave Propagation Laboratory, and MSFC using existing lidar hardware and manpower resources. Several lidar components have already been exercised in previous airborne lidar programs (for example, MSFC Airborne Doppler Lidar System (ADLS) used in 1981,4 Severe Storms Wind Measurement Program; JPL Airborne Backscatter Lidar Experiment (ABLE) used in 1989,90 Global Backscatter Experiment Survey Missions). MSFC has been given responsibility for directing the overall program of instrument development and scientific measurement. The focus of current research and plans for next year are presented.

Rhothermel, Jeffry↗
NASA NTRS1993

Commercial Applications Multispectral Sensor System

NASA's Office of Commercial Programs is funding a multispectral sensor system to be used in the development of remote sensing applications. The Airborne Terrestrial Applications Sensor (ATLAS) is designed to provide versatility in acquiring spectral and spatial information. The ATLAS system will be a test bed for the development of specifications for airborne and spaceborne remote sensing instrumentation for dedicated applications. This objective requires spectral coverage from the visible through thermal infrared wavelengths, variable spatial resolution from 2-25 meters; high geometric and geo-location accuracy; on-board radiometric calibration; digital recording; and optimized performance for minimized cost, size, and weight. ATLAS is scheduled to be available in 3rd quarter 1992 for acquisition of data for applications such as environmental monitoring, facilities management, geographic information systems data base development, and mineral exploration.

Birk, Ronald J.↗
NASA NTRS1992

Commercial applications multispectral sensor system

NASA's Office of Commercial Programs is funding a multispectral sensor system to be used in the development of remote sensing applications. The Airborne Terrestrial Applications Sensor (ATLAS) is designed to provide versatility in acquiring spectral and spatial information and will be a test bed for the development of specifications for airborne and spaceborne remote sensing instrumentation for dedicated applications. This objective requires spectral coverage from the visible through thermal IR wavelengths, variable spatial resolution form 2-25 meters; high geometric and geolocation accuracy; on-board radiometric calibration; digital recording; and optimized performance for minimized cost, size, and weight.

Birk, Ronald J.↗
NASA NTRS1991

The application of geologic remote sensing to vertebrate biostratigraphy - General results from the Wind River Basin, Wyoming

Since 1986, remote sensing images derived from satellite and aircraft-borne sensor data have been used to study the stratigraphy and sedimentology of the vertebrate-bearing Wind River and Wagon Bed formations in the Wind River Basin (Wyoming). Landsat 5 TM and aircraft Thermal Infrared Multispectral Scanner data were combined with conventional geologic analyses. The remote sensing data have contributed significantly to: (1) geologic mapping at the formation, member, and bed levels; (2) stratigraphic correlation; (3) reconstruction of ancient depositional environments; and (4) identification of structural complexity. This information is critical to vertebrate paleontology in providing the stratigraphic, sedimentologic, and structural framework required for evolutionary and paleoecologic studies. Of primary importance is the ability to map at minimal cost the geology of large areas (20,000 sq km or greater) at a high level of precision. Remote sensing data can be especially useful in geologically and paleontologically unexplored or poorly understood regions.

Stucky, Richard K.↗
NASA NTRS1992

Characterization of a Nd:YAG doubled pulsed laser system

A description of a frequency doubled, double pulsed Nd:YAG laser that is to be used to pump an injection locked Ti:Sapphire power oscillator is presented. These two lasers make up the transmitter portion of the Lidar Atmospheric Sensing Experiment (LAWSE) instrument. LASE is a Lidar/DIAL experiment that is to measure water vapor in the troposphere. By utilizing the twin concept, both pulses can be produced with a single laser system, thereby minimizing cost, size, and weight. Alignment problems associated with having two separate lasers each produce one of the twin pulses are also alleviated. The LASE transmitter consists of a doubled pulsed Nd:YAG laser that will pump a Ti:Sapphire power oscillator that will be injection-locked by a diode laser. The wavelength of the Ti:Sapphire output will be tunable from 813 to 818 nm. A performance summary of the pump laser is given. The data verify that the pump laser can meet the performance requirements to pump the Ti:Sapphire power oscillator.

Williams-Byrd, Julie A.↗
NASA NTRS1994

Multiblock, Multigrid Solution Of Euler Equations

Method of numerical solution of Euler equations of three-dimensional flow of compressible fluid involves combination of multiblock and multigrid strategies. In multiblock strategy, flow field divided, into multiple smaller, more computationally-convenient zones and computational grid fitted to applicable flow boundaries generated in each block. In multigrid strategy used here, different quantities computed, variously, on finer or coarser grids. Minimizing cost of computation by using fewest grid points yielding acceptably accurate values of affected variable. Multigrid strategy found effective in accelerating convergence to steady state, while multiblock strategy provides geometric flexibility.

Melson, N. Duane↗
NASA NTRS1991

Use of ground-penetrating radar techniques in archaeological investigations

Ground-penetrating radar (GPR) techniques are increasingly being used to aid reconnaissance and pre-excavation surveys at many archaeological sites. As a 'remote sensing' tool, GPR provides a high resolution graphic profile of the subsurface. Radar profiles are used to detect, identify, and locate buried artifacts. Ground-penetrating radar provides a rapid, cost effective, and nondestructive method for identification and location analyses. The GPR can be used to facilitate excavation strategies, provide greater areal coverage per unit time and cost, minimize the number of unsuccessful exploratory excavations, and reduce unnecessary or unproductive expenditures of time and effort.

Doolittle, James A.↗
NASA NTRS1989

Design of a Solar Sail Mission to Mars

A new area of interest in space vehicles is the solar sail. Various applications for which it has been considered are attitude control of satellites, focusing light on the jungles of Vietnam, and a Halley's comet rendezvous. Although for various reasons these projects were never completed, new interest in solar sails has arisen. The solar sail is an alternative to the rocket-propelled space vehicle as an interplanetary cargo vehicle, and manufacture of solar sails on the space station is a possibility. Solar sails have several advantages over rockets, including an unlimited power supply and low maintenance. The purpose of this project is to design a solar sail mission to Mars. The spacecraft will efficiently journey to Mars powered only by a solar sail. The vehicle weighs 487.16 kg and will be launchable on an expendable launch vehicle. The project includes an investigation of options to minimize cost, weight, and flight duration. The design of the sail and its deployment system are a major part of the project, as is the actual mission planning. Various topics researched include solar power, material, space environment, thermal control, trajectories, and orbit transfer. Various configurations are considered in order to determine the optimal structure. Another design consideration is the control system of the vehicle. This system includes the attitude control and the communication system of the sail. This project will aid in determining the feasibility of a solar sail and will raise public interest in space research.

Feaux, K.↗
NASA NTRS1993

The role of NASTRAN in the preliminary design cycle

This paper explains how NASTRAN can be utilized advantageously in the preliminary design cycle. The initial portion of the preliminary design process lends itself to programs that can produce multiple configurations or variations on a particular design with minimal cost or effort. The latter portion of the process encompasses refining the design and adding more detailed analyses (particularly for other disciplines). A method for quickly generating balanced spacecraft loading conditions for use in preliminary design and analysis also is explained. The following additional sections are included: Background, Symbols, Analytical Process, Aerodynamic Load Distributions, NASTRAN Applications, Conclusion and References.

Grooms, H. R.↗
NASA NTRS1992

Space Habitat, assembly and repair facility

Integrated Space Systems (ISS) has designed a Low Earth Orbit Assembly Facility for submission in the 1992 AIAA/LORAL Team Space Design Competition. This facility, the Space Habitat, Assembly, and Repair Center (SHARC), will be used to construct, assemble, and service space vehicles. SHARC's primary mission will be the construction of interplanetary vehicles, but it will also be able to perform repair and refueling operations of craft which are in an Earth orbit. This facility has been designed using only present and near-present technology. The emphasis is on minimizing cost.

Colangelo, Todd A.↗
NASA NTRS1994

Robotic NDE inspection of advanced solid rocket motor casings

The Advanced Solid Rocket Motor program determined the need to inspect ASRM forgings and segments for potentially catastrophic defects. To minimize costs, an automated eddy current inspection system was designed and manufactured for inspection of ASRM forgings in the initial phases of production. This system utilizes custom manipulators and motion control algorithms and integrated six channel eddy current data acquisition and analysis hardware and software. Total system integration is through a personal computer based workcell controller. Segment inspection demands the use of a gantry robot for the EMAT/ET inspection system. The EMAT/ET system utilized similar mechanical compliancy and software logic to accommodate complex part geometries. EMAT provides volumetric inspection capability while eddy current is limited to surface and near surface inspection. Each aspect of the systems are applicable to other industries, such as, inspection of pressure vessels, weld inspection, and traditional ultrasonic inspection applications.

Mcneelege, Glenn E.↗
NASA NTRS1994

RINGSAT

Radio frequency interference (RFI) presents a serious problem to naval communications. Unauthorized transmissions on the same frequencies that FLTSAT or LEASAT use cause a loss of one or more transponders on a satellite. The problem is not correctable until the emitter is located and turned off, or until it runs off on its own. The present geolocation system cannot deal with the RFI problem adequately. This causes the Navy to lose operational capability and money. The proposed Radio Frequency Interference Navy Geolocation Satellite (RINGSAT) would locate the source of the interference within 3 hours, an outstanding improvement over current equipment. Furthermore, RINGSAT can be built quickly, at minimal cost, and can be used concurrently for other military missions. Currently, geolocation to identify the RFI is done at Naval Space Command. Using single satellite doppler, time delay of arrival, and frequency delay of arrival techniques, it is possible to locate the interfering emitter. However, for the first quarter of fiscal year 1993, about 50 different channels used by the Navy were nonoperational for over 500 hours. Almost 30 percent of the interference occurrences lasted for over 12 hours. In only one quarter of the cases was the interference turned off in less than two_hours either by our detection or on its own.

DOWDY↗