IMPULSIVE MHD DEVICES AS SPACE ENGINES
Proposed impulsive magnetohydrodynamic device for spacecraft power supplies, using a plasma gun without destructive electrode losses
PLASMA GUN↗
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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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Preregulator feedback circuit utilizes Light Actuated Switch
Preregulator feedback circuit employing a Light Actuated Switch /LAS/ provides a simple and efficient feedback device in a power supply preregulator which maintains dc isolation between input and output grounds. The LAS consists of a diode PN junction infrared source close to, but electrically isolated from, a photodetector.
Hayser, T. P.↗
Residual magnetism holds solenoid armature in desired position
Holding solenoid uses residual magnetism to hold its armature in a desired position after excitation current is removed from the coil. Although no electrical power or mechanical devices are used, the solenoid has a low tolerance to armature displacement from the equilibrium position.
Crawford, R. P.↗
Toward aircraft of the 1980s.
Aircraft in 1980s noting V/STOL air transportation, government intervention, thrust devices and nuclear power
Chatham, G. N.↗
Portable circuit-interruption indicator
Device locates transient power interruptions occurring in electrical equipment. Indicator operates on principle that circuit in normal use retains residual current in the line prior to an interruption.
Bezant, K. R.↗
Coaxial Inverted Geometry Epitaxial Transistor
Silicon transistor, developed for use in biotelemetry circuits, provides high current gain at low levels of power and voltage. Device operates from biopotential or miniature batteries and is suitable for incorporation into monolithic integrated circuits. Coaxial configuration and small size offer promise for high frequency application.
Hruby, R. J.↗
Simple dynamic electromagnetic radiation detector
Detector monitors gamma dose rate at particular position in a radiation facility where a mixed neutron-gamma environment exists, thus determining reactor power level changes. Device also maps gamma intensity profile across a neutron-gamma beam.
Been, J. F.↗
Gas lasers and applications
A brief review of laser elements is given. Flowing gas lasers are represented to have the best potential for high average power. The background of shock-tube researchers and the shock tube itself are alleged to be ideally suited for the development of such lasers. Three types - the electric discharge, the gasdynamic, and the chemical laser - are discussed briefly. A legion number of possible gas lasers is enumerated. With the development of their potential for higher power and efficiency, many additional and important uses of lasers are predicted, even beaming power through space for long distances, up to 1 AU. A few details of some current high-power gasdynamic laser devices are given.
Hansen, C. F.↗
Changes in the performance characteristics of a GaAs near infrared light emitting diode when exposed to various current and thermal stresses
The changes that occurred in the optical and electrical characteristics of a near infrared, GaAs light emitting diode, when operated under various levels and combinations of current and thermal stresses are discussed. A total of forty parts were operated for two thousand hours under eight different sets of dc current and ambient temperature conditions. Degradation in the radiant optical power of these devices was thirty-four percent when operated at their rated current and an ambient temperature of 298K (25 C). Derating the current and/or the thermal stress reduced the degradation of this parameter in approximately a linear manner. All degraded devices behaved similarly, exhibiting rapid nonlinear degradation followed by a gradual linear degradation and finally a period of stable operation. An attempt was made to correlate initial device condition to degradation during stress testing, but met with little success.
Thomas, E. F., Jr.↗
Constant-power source for resistive load
Device uses operational amplifiers, dividers, subtractor, pulsed reference amplifier, and associated integrated-circuit components to deliver constantly-adjustable continual power to variable-resistance load for specialized low-power instrumentation applications.
Nagle, E. M.↗
Overload protection system
Overload protection circuit utilizes one circuit for suspending inverter action when load abnormality is detected and second circuit to monitor clearance of abnormality. Device wastes no power during normal operating conditions and responds instantaneously when abnormality is cleared.
Nagano, S.↗
Antitheft container for instruments
Antitheft container is used to prevent theft of calculators, portable computers, and other small instruments. Container design is simple and flexible enough to allow easy access to display or input systems of instruments, while not interfering with power input to device.
Kerley, J. J., Jr.↗
Study of advanced electric propulsion system concept using a flywheel for electric vehicles
Advanced electric propulsion system concepts with flywheels for electric vehicles are evaluated and it is predicted that advanced systems can provide considerable performance improvement over existing electric propulsion systems with little or no cost penalty. Using components specifically designed for an integrated electric propulsion system avoids the compromises that frequently lead to a loss of efficiency and to inefficient utilization of space and weight. A propulsion system using a flywheel power energy storage device can provide excellent acceleration under adverse conditions of battery degradation due either to very low temperatures or high degrees of discharge. Both electrical and mechanical means of transfer of energy to and from the flywheel appear attractive; however, development work is required to establish the safe limits of speed and energy storage for advanced flywheel designs and to achieve the optimum efficiency of energy transfer. Brushless traction motor designs using either electronic commutation schemes or dc-to-ac inverters appear to provide a practical approach to a mass producible motor, with excellent efficiency and light weight. No comparisons were made with advanced system concepts which do not incorporate a flywheel.
Younger, F. C.↗
Minus 55 to plus 200 deg C 12 bit analog-to-digital converter
A 12 bit successive approximation analog to digital converter that offers moderately high speed precision data conversion at a reasonable level of cost and complexity is studied. The ADCH10HT extends this capability over a temperature range of -55 to +200 C. No missing-code performance is maintained over the entire temperature range. The converter is completely self-contained with internal clock and +10 volt reference. The CMOS devices offer low power dissipation, so that the internal temperature of the hybrid circuit does not rise as much from self heating. In CMOS circuits, pn junction leakage currents are returned to the supplies so that the logic keeps working at temperatures up to 250 C.
Smith, L. R.↗
Magnetic field control
A torque control for an electromechanical torquing device of a type where a variable clearance occurs between a rotor and field is described. A Hall effect device senses the field present, which would vary as a function of spacing between field and rotor. The output of the Hall effect device controls the power applied to the field so as to provide a well defined field and thus a controlled torque to the rotor which is well defined.
Haeussermann, W.↗
Spacecraft automatic umbilical system
A conceptual definition of an appropriate berthing technique and a prototype design of an automatic umbilical system suitable for use with payloads carried by the Space Shuttle are presented. A four-element berthing system is described. This concept consists of a set of four remote manipulator system (RMS)-type end-effector capture/tie-down devices on the power system and corresponding RMS-type grapple fittings on the payload. In operation, the RMS maneuvers the payload to a position where the four grapple fittings can be snared within the end-effectors and then secured to the power system. The concept takes advantage of mechanisms and operating techniques developed for attaching the RMS to a payload. Although the umbilical installation is attached to the docking interface structure, its operation is independent and it must comply with a set of primary requirements specified by Marshall Space Flight Center (MSFC), which is presented.
Rudy, G. C.↗
New developments in power semiconductors
This paper represents an overview of some recent power semiconductor developments and spotlights new technologies that may have significant impact for aircraft electric secondary power. Primary emphasis will be on NASA-Lewis-supported developments in transistors, diodes, a new family of semiconductors, and solid-state remote power controllers. Several semiconductor companies that are moving into the power arena with devices rated at 400 V and 50 A and above are listed, with a brief look at a few devices.
Sundberg, G. R.↗
Positive-Index Guiding in CDH-LOC Lasers
Nonabsorbing passive region has beam-guiding capability. Convex-lensshaped layer has refractive index higher than surrounding material so serves as optical waveguide. Four times more power achieved for devices of this type not incorporating the passive region.
Botez, D.↗