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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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Space Laser Power Transmission System Studies
Power transmission by laser technique is addressed. Space to Earth and space to space configurations are considered.
Magnetic penetration depth of YBa2Cu3O(7-delta) thin films determined by the power transmission method
A power transmission measurement technique was used to determine the magnetic penetration depth (lambda) of YBa2Cu3O(7-delta) superconducting thin films on LaAlO3 within the 26.5 to 40.0 GHz frequency range, and at temperatures from 20 to 300 K. Values of lambda ranging from 1100 to 2500 A were obtained at low temperatures. The anisotropy of lambda was determined from measurements of c-axis and a-axis oriented films. An estimate of the intrinsic value of lambda of 90 +/- 30 nm was obtained from the dependence of lambda on film thickness. The advantage of this technique is that it allows lambda to be determined nondestructively.
One-megawatt solar pumped and electrically driven lasers for space power transmission
High power lasers in space could provide power for a variety of future space missions such as spacecraft electric power requirements and laser propulsion. This study investigates four electrically pumped laser systems, krypton fluoride, copper vapor, laser diode array, and the carbon dioxide laser, all scaled to 1-MW laser output. Each system obtained its primary power from a large solar photovoltaic array which, in turn, provides power for the appropriate laser power conditioning subsystem. Each system was block-diagrammed, and the power and efficiency were found for each subsystem. The laser diode array had the highest solar-to-laser efficiency (6 percent) and smallest radiator area making it the most advantageous of the electrically driven lasers studied. This system was then compared with an iodine solar pumped laser system previously studied. The diode array had a better wavelength with regard to transmission optics mass, but it also had a heavier radiator because of its lower temperature radiator requirement. A more advanced solar pumped laser could emerge as the preferred laser system for space applications.
Microwave power transmission system wherein level of transmitted power is controlled by reflections from receiver
A microwave, wireless, power transmission system is described in which the transmitted power level is adjusted to correspond with power required at a remote receiving station. Deviations in power load produce an antenna impedance mismatch causing variations in energy reflected by the power receiving antenna employed by the receiving station. The variations in reflected energy are sensed by a receiving antenna at the transmitting station and used to control the output power of a power transmitter.
Power availability at terrestrial receptor sites for laser-power transmission from the satellite power system
A statistical model was developed for relating the temporal transmission parameters of a laser beam from a solar power satellite to observable meteorological data to determine the influence of weather on power reception at the earth-based receiver. Sites within 100 miles of existing high voltage transmission lines were examined and the model was developed for clear-sky and clouded conditions. The cases of total transmission through clouds at certain wavelengths, no transmission, and partial transmission were calculated for the cloud portion of the model. The study covered cirriform, stratiform, cumiliform, and mixed type clouds and the possibility of boring holes through the clouds with the beam. Utilization of weapons-quality beams for hole boring, was found to yield power availability increases of 9-33%, although no beneficial effects could be predicted in regions of persistent cloud cover. An efficiency of 80% was determined as possible if several receptor sites were available within 200-300 miles of each other, thereby allowing changes of reception point in cases of unacceptable meteorological conditions.
Space Policy Issues of Space Solar Power Wireless Power Transmission
The use of wireless power transmission in Space Solar Power activities creates significant policy issues regarding the beam right-of-way.
Locating the Source of Forced Oscillations in Transmission Power Grids
A forced oscillation event in power grids refers to a state where malfunctioning or abnormally operating equipment causes persisting periodic disturbances in the system. While power grids are designed to damp most perturbations during standard operations, some of them can excite normal modes of the system and cause significant energy transfers across the system, creating large oscillations thousands of miles away from the source. Localization of the source of such disturbances remains an outstanding challenge due to a limited knowledge of the system parameters outside of the zone of responsibility of system operators. Here, we propose a new method for locating the source of forced oscillations that addresses this challenge by performing a simultaneous dynamic model identification using a principled maximum likelihood approach. We illustrate the validity of the algorithm on a variety of examples where forcing leads to resonance conditions in the system dynamics. Our results establish that an accurate knowledge of system parameters is not required for a successful inference of the source and frequency of a forced oscillation. We anticipate that our method will find a broader application in general dynamical systems that can be well described by their linearized dynamics over short periods of time.
Solar power satellite microwave power transmission and reception system
The microwave power transmission and reception system of the Satellite Power System (SPS) has been intensively reviewed and assessed in a three-year concept development and evaluation program. This paper will review some concepts of SPS with particular emphasis on the design of the microwave power transmission and reception system. Technology requirements and proposals for meeting them will be discussed for various parts of the microwave system and to some degree for critical components such as power amplifiers. Specific subjects to be discussed are SPS concepts, antenna design, phase control, rectenna, and technology.
Enabling lunar and space missions by laser power transmission
Applications are proposed for laser power transmission on the Moon. A solar-pumped laser in lunar orbit would beam power to the lunar surface for conversion into either electricity or propulsion needs. For example, lunar rovers could be much more flexible and lighter than rovers using other primary power sources. Also, laser power could be absorbed by lunar soil to create a hard glassy surface for dust-free roadways and launch pads. Laser power could also be used to power small lunar rockets or orbital transfer vehicles, and finally, photovoltaic laser converters could power remote excavation vehicles and human habitats. Laser power transmission is shown to be a highly flexible, enabling primary power source for lunar missions.
Free-Space Power Transmission
NASA Lewis Research Center organized a workshop on technology availability for free-space power transmission (beam power). This document contains a collection of viewgraph presentations that describes the effort by academia, industry, and the national laboratories in the area of high-frequency, high-power technology applicable to free-space power transmission systems. The areas covered were rectenna technology, high-frequency, high-power generation (gyrotrons, solar pumped lasers, and free electron lasers), and antenna technology.
Ground Based Wireless and Wired Power Transmission Cost Comparison
Recent interest in applications of wireless power transmission has raised the question of the cost comparison of wireless vs wired transmission of power from ground site to ground site.
Wireless power transmission in a space environment
Microwave power transmission for supplying electric power to space station complex for performing scientific experiments over long periods in earth orbits
Design study for a gound microwave power transmission system for use with a high-altitude powered platform
The conceptual design of a ground-based microwave power transmission system is described. This system is intended to supply electrical power via an air link to a high-altitude (21 km) powered platform. The platform must be equipped with the required instrumentation (RECTENNA) to convert the RF energy to dc power.
Power transmission cable development for the Space Station Freedom electrical power system
Power transmission cable is presently being evaluated under a NASA Lewis Research Center advanced development contract for application in the Space Station Freedom (SSF) electrical power system (EPS). Evaluation testing has been performed by TRW and NASA Lewis Research Center. The results of this development contract are presented. The primary cable design goals are to provide (1) a low characteristic inductance to minimize line voltage drop at 20 kHz, (2) electromagnetic compatibility control of the 20-kHz ac power current, (3) a physical configuration that minimizes ac resistance and (4) release of trapped air for corona-free operation.
Determination of surface resistance and magnetic penetration depth of superconducting YBa2Cu3O(7-delta) thin films by microwave power transmission measurements
A novel waveguide power transmission measurement technique was developed to extract the complex conductivity of superconducting thin films at microwave frequencies. The microwave conductivity was taken of two laser ablated YBa2Cu3O(7-delta) thin films on LaAlO3 with transition temperatures of approx. 86.3 and 82 K, respectively, in the temperature range 25 to 300 K. From the conductivity values, the penetration depth was found to be approx. 0.54 and 0.43 micron, and the surface resistance (R sub s) to be approx. 24 and 36 micro-Ohms at 36 GHz and 76 K for the two films under consideration. The R sub s values were compared with those obtained from the change in the Q-factor of a 36 GHz Te sub 011-mode (OFHC) copper cavity by replacing one of its end walls with the superconducting sample. This technique allows noninvasive characterization of high transition temperature superconducting thin films at microwave frequencies.
Determination of surface resistance and magnetic penetration depth of superconducting YBa2Cu3O(7-delta) thin films by microwave power transmission measurements
A novel waveguide power transmission measurement technique was developed to extract the complex conductivity of superconducting thin films at microwave frequencies. The microwave conductivity was taken of two laser ablated YBa2Cu3O(7-delta) thin films on LaAlO3 with transition temperatures of approximately 86.3 and 82 K, respectively, in the temperature range 25 to 300 K. From the conductivity values, the penetration depth was found to be approximately 0.54 and 0.43 micron, and the surface resistance (R sub s) to be approximately 24 and 36 micro-Ohms at 36 GHz and 76 K for the two films under consideration. The R sub s values were compared with those obtained from the change in the Q-factor of a 36 GHz Te sub 011-mode (OFHC) copper cavity by replacing one of its end walls with the superconducting sample. This technique allows noninvasive characterization of high transition superconducting thin films at microwave frequencies.
Study of novel concepts of power transmission gears
Two concepts in power transmission gear design are proposed which provide a potential for large noise reduction and for improving weight to payload ratio due to use of advanced fiber reinforced and ceramic materials. These concepts are briefly discussed. Since both concepts use ultrathin layered rubber-metal laminates for accommodating limited travel displacements, properties of the laminates, such as their compressive strength, compressive and shear moduli were studied. Extensive testing and computational analysis were performed on the first concept gears (laminate coated conformal gears). Design and testing of the second conceptual design (composite gear with separation of sliding and rolling motions) are specifically described.