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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 1,495 records · Page 83
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Simulation evaluation of flight controls and display concepts for VTOL shipboard operations

A ground-based evaluation of several control-system concepts and display formats for use in shipboard landing operations of a V/STOL aircraft (AV-8A Harrier) is reported. The study was conducted in the Vertical Motion Simulator at Ames Research Center. The control systems ranged from a rate-damping SAS to a translational-velocity command system; displays ranged from a head-down presentation of attitude and altitude to two different head-up formats that provided position and velocity information. Results of pilot evaluations of the aircraft's handling qualities, as well as measures of task performance and control power use during landing on a moving deck in visual meteorological condtions, are presented.

Farris, G. G.↗
NASA NTRS1984

Integrated-optical approaches to matrix multiplication

The solution of matrix equations is essential to carrying out a large variety of control algorithms and to reducing certain types of data such as the output of a multispectral sensor array. Optical techniques and, in particular, integrated-optical circuits (IOC's) can provide compact, low-power devices for performing the mitrix multiplications necessary for the solution of these problems. A specific IOC for performing vector-matrix multiplication and several approaches to the design of IOC's for matrix-matrix multiplication will be discussed.

Verber, C. M.↗
NASA NTRS1984

K-Band Latching Switches

Design, development, and tests are described for two single-pole-double-throw latching waveguide ferrite switches: a K-band switch in WR-42 waveguide and a Ka-band switch in WR-28 waveguide. Both switches have structurally simple junctions, mechanically interlocked without the use of bonding materials; they are impervious to the effects of thermal, shock, and vibration stresses. Ferrite material for the Ka-band switch with a proper combination of magnetic and dielectric properties was available and resulted in excellent low loss, wideband performance. The high power handling requirement of the K-band switch limited the choice of ferrite to nickel-zinc compositions with adequate magnetic properties, but with too low relative dielectric constant. The relative dielectric constant determines the junction dimensions for given frequency responses. In this case the too low value unavoidably leads to a larger than optimum junction volume, increasing the insertion loss and restricting the operating bandwidth. Efforts to overcome the materials-related difficulties through the design of a composite junction with increased effective dielectric properties efforts to modify the relative dielectric constant of nickel-zinc ferrite are examined.

Piotrowski, W. S.↗
NASA NTRS1984

LaRC local area networks to support distributed computing

The Langley Research Center's (LaRC) Local Area Network (LAN) effort is discussed. LaRC initiated the development of a LAN to support a growing distributed computing environment at the Center. The purpose of the network is to provide an improved capability (over inteactive and RJE terminal access) for sharing multivendor computer resources. Specifically, the network will provide a data highway for the transfer of files between mainframe computers, minicomputers, work stations, and personal computers. An important influence on the overall network design was the vital need of LaRC researchers to efficiently utilize the large CDC mainframe computers in the central scientific computing facility. Although there was a steady migration from a centralized to a distributed computing environment at LaRC in recent years, the work load on the central resources increased. Major emphasis in the network design was on communication with the central resources within the distributed environment. The network to be implemented will allow researchers to utilize the central resources, distributed minicomputers, work stations, and personal computers to obtain the proper level of computing power to efficiently perform their jobs.

Riddle, E. P.↗
NASA NTRS1984

The 20 GHz solid state transmitter design, impatt diode development and reliability assessment

A single drift gallium arsenide (GaAs) Schottky barrier IMPATT diode and related components were developed. The IMPATT diode reliability was assessed. A proof of concept solid state transmitter design and a technology assessment study were performed. The transmitter design utilizes technology which, upon implementation, will demonstrate readiness for development of a POC model within the 1982 time frame and will provide an information base for flight hardware capable of deployment in a 1985 to 1990 demonstrational 30/20 GHz satellite communication system. Life test data for Schottky barrier GaAs diodes and grown junction GaAs diodes are described. The results demonstrate the viability of GaAs IMPATTs as high performance, reliable RF power sources which, based on the recommendation made herein, will surpass device reliability requirements consistent with a ten year spaceborne solid state power amplifier mission.

Picone, S.↗
NASA NTRS1986

Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

Bhasin, K. B.↗
NASA NTRS1986

Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

Bhasin, K. B.↗
NASA NTRS1986

Development of sensor augmented robotic weld systems for aerospace propulsion system fabrication

In order to meet stringent performance goals for power and reuseability, the Space Shuttle Main Engine was designed with many complex, difficult welded joints that provide maximum strength and minimum weight. To this end, the SSME requires 370 meters of welded joints. Automation of some welds has improved welding productivity significantly over manual welding. Application has previously been limited by accessibility constraints, requirements for complex process control, low production volumes, high part variability, and stringent quality requirements. Development of robots for welding in this application requires that a unique set of constraints be addressed. This paper shows how robotic welding can enhance production of aerospace components by addressing their specific requirements. A development program at the Marshall Space Flight Center combining industrial robots with state-of-the-art sensor systems and computer simulation is providing technology for the automation of welds in Space Shuttle Main Engine production.

Jones, C. S.↗
NASA NTRS1986

Space Station technology experiments and uses

The use of the proposed Space Station for technological experimentation is discussed. The general objectives and capabilities of the Station and the status of planning are reviewed; the external and internal environmental conditions at the 500-km 28.5-deg-inclination Station orbit are described; and six conceptual Technology Development Missions designed by NASA and included in the Mission Requirements Data Base are briefly characterized and illustrated with drawings. The missions considered concern spacecraft-materials performance, solar dynamic power, data transfer and processing microelectronics, long-term cryogenic-fluid storage, active-optics technology, and cryogenic-propellant transfer, storage, and reliquefaction.

Breckenridge, R. A.↗
NASA NTRS1987

The NASA/USAF arcjet research and technology program

Direct current arcjets have the potential to provide specific impulses greater than 500 sec with storable propellants, and greater than 1000 sec with hydrogen. This level of performance can provide significant benefits for such applications as orbit transfer, station keeping, orbit change, and maneuvering. The simplicity of the arcjet system and its elements of commonality with state-of-the-art resistojet systems offer a relatively low risk transition to these enhanced levels of performance for low power (0.5 to 1.5 kW) station keeping applications. Arcjets at power levels of 10 to 30 kW are potentially applicable to orbit transfer missions. Furthermore, with the anticipated development of space nuclear power systems, arcjets at greater than 100 kW may become attractive. This paper describes the ongoing NASA/USAF program and describes major recent accomplishments.

Stone, James R.↗
NASA NTRS1986

Prototype thermal bus for manned Space Station compartments

A summary is presented of NASA efforts, to February 1986, on development of an advanced thermal bus for manned spacecraft. Design details are described for a prototype to be tested in 1987 that includes a contact heat exchanger, an air cooling heat exchanger for manned cabin conditions, and an interface heat exchanger for transferring compartment heat loads to the Space Station Central Thermal Bus. The design and performance criteria defined for the thermal bus are outlined and results are reported from comparisons of the capabilities and operational costs of pumped water and two-phase evaporating/condensing heat transport concepts. The operating temperature, launch weight/thermal performance ratios, and power requirements of each concept are discussed, along with the critical technologies identified for use of a water/titanium two-phase thermal bus.

Zentner, Ronald C.↗
NASA NTRS1987

The NASA/USAF arcjet research and technology program

Direct current arcjets have the potential to provide specific impulses greater than 500 sec with storable propellants, and greater than 1000 sec with hydrogen. This level of performance can provide significant benefits for such applications as orbit transfer, station keeping, orbit change, and maneuvering. The simplicity of the arcjet system and its elements of commonality with state-of-the-art resistojet systems offer a relatively low risk transition to these enhanced levels of performance for low power (0.5 to 1.5 kW) station keeping applications. Arcjets at power levels of 10 to 30 kW are potentially applicable to orbit transfer missions. Furthermore, with the anticipated development of space nuclear power systems, arcjets at greater than 100 kW may become attractive. This paper describes the ongoing NASA/USAF program and describes major recent accomplishments.

Stone, James R.↗
NASA NTRS1987

A feasibility study of a hypersonic real-gas facility

A four month feasibility study of a hypersonic real-gas free flight test facility for NASA Langley Research Center (LARC) was performed. The feasibility of using a high-energy electromagnetic launcher (EML) to accelerate complex models (lifting and nonlifting) in the hypersonic, real-gas facility was examined. Issues addressed include: design and performance of the accelerator; design and performance of the power supply; design and operation of the sabot and payload during acceleration and separation; effects of high current, magnetic fields, temperature, and stress on the sabot and payload; and survivability of payload instrumentation during acceleration, flight, and soft catch.

Gully, J. H.↗
NASA NTRS1988

Future spacecraft propulsion

Propulsion requirements for launch vehicles, upper stages, satellites and platforms, and planetary spacecraft are described from a functional perspective and compared on an energy basis. Mission velocity requirements for a range of missions are presented. A simple model relating optimum exhaust velocity and maximum system delta-V as a function of system-specific energy is developed, which provides insight into the relationship between system performance and various power and propulsion subsystem characteristics. Based on this model, various advanced propulsion options, e.g., the solid-core nuclear rocket and nuclear electric propulsion, are evaluated, and the implications of this analysis for propulsion and power system technology development programs are discussed. The objective of this paper is to provide an overview of future propulsion requirements for the nonspecialist.

Garrison, P. W.↗
NASA NTRS1990

Rotating-unbalanced-mass Devices for Scanning Balloon-borne Experiments, Free-flying Spacecraft, and Space Shuttle/space Station Experiments

A new method is presented for scanning balloon-borne experiments, free-flying spacecraft, and gimballed experiments mounted to the space shuttle or the space station. It uses rotating-unbalanced-mass (RUM) devices for generating circular, line, or raster scan patterns and an auxiliary control system for target acquisition, keeping the scan centered on the target, and producing complementary motion for raster scanning. It is ideal for applications where the only possible way to accomplish the required scan is to physically scan the entire experiment or spacecraft as in x ray and gamma ray experiments. In such cases, this new method should have advantages over prior methods in terms of either power, weight, cost, performance, stability, or a combination of these.

Polites, Michael E.↗
NASA NTRS1990

Implementation strategies for load center automation on the space station module/power management and distribution testbed

The Space Station Module/Power Management and Distribution (SSM/PMAD) testbed was developed to study the tertiary power management on modules in large spacecraft. The main goal was to study automation techniques, not necessarily develop flight ready systems. Because of the confidence gained in many of automation strategies investigated, it is appropriate to study, in more detail, implementation strategies in order to find better trade-offs for nearer to flight ready systems. These trade-offs particularly concern the weight, volume, power consumption, and performance of the automation system. These systems, in their present implementation are described.

Watson, Karen↗
NASA NTRS1990

Systems analysis of Mars solar electric propulsion vehicles

Mission performance, mass, initial power, and cost are determined for solar electric propulsion vehicles across a range of payload masses, reference powers, and mission trajectories. Thick radiation shielding is added to arrays using indium phosphide or III-V multijunction solar cells to reduce the damage incurred through the radiation belts. Special assessments of power management and distribution systems, atmospheric drag, and energy storage are made. It is determined that atmospheric drag is of no great concern and that the energy storage used in countering drag is unnecessary. A scheme to package the arrays, masts, and ion thrusters into a single fairing is presented.

Hickman, J. M.↗
NASA NTRS1991

New method for scanning spacecraft and balloon-borne/space-based experiments

A new method is presented for scanning balloon-borne experiments, free-flying spacecraft, and gimballed experiments mounted to the space shuttle or the space station. It uses rotating-unbalanced-mass (RUM) devices for generating circular, line, or raster scan patterns and an auxiliary control system for target acquisition, keeping the scan centered on the target, and producing complementary motion for raster scanning. It is ideal for applications where the only possible way to accomplish the required scan is to physically scan the entire experiment or spacecraft as in X-ray and gamma ray experiments. In such cases, this new method should have advantages over prior methods in terms of either power, weight, cost, performance, stability, or a combination of these.

Polites, Michael E.↗