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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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A solar photovoltaic satellite based upon the utilization of a GaAlAs solar cell is defined. Topics covered include silicon-based photovoltaics, solar thermal power conversion, microwave energy transmission, power distribution, structures, attitude control and stationkeeping, thermal, and information management and control.
An environmentally oriented microwave technology exploratory research program aimed at reducing the uncertainty associated with microwave power system critical technical issues is described. Topics discussed include: (1) Solar Power Satellite System (SPS) development plan elements; (2) critical technology issues related to the SPS preliminary reference configuration; (3) pilot plant to demonstrate commercial viability of the SPS system; and (4) research areas required to demonstrate feasibility of the SPS system. Progress in the development of advanced GaAs solar cells is reported along with a power distribution subsystem.
A two dimensional discrete vortex model is applied to turbulent flow over a cavity at a Reynolds number based on cavity half length of approximately 500,000. These model predictions are compared with experimental data on a time average and on a spectral basis. The comparisons indicate that the vortex model reproduces the mean velocity profiles of this complex flow, while the turbulent intensity and Reynolds stress profiles are overpredicted in magnitude. Spectral analyses show that the vortex model introduces unrealistic low frequency power which becomes less dominant as the model becomes more disordered. The spectral power distribution of the model in this state is nearly in agreement with that of the data, somewhat too low at the higher frequencies and too high at the lower frequencies. The model is shown to be capable of reproducing the cavity feedback oscillation phenomenon.
The paper investigates the system performance and antenna characteristics under startup/shutdown conditions for the high power beam from a solar power satellite. Attention is given to the present microwave system reference configuration together with the dc power distribution system in the solar array and in the antenna. The pattern characteristics for the main beam, sidelobes, and grating lobes are examined for eight types of energizing configurations which include: random sequences, two types of concentric circles, and three types of line strips. In conclusion, it is noted that a proper choice of sequences should not cause environmental problems due to increased microwave radiation levels during the short time periods of energizing and de-energizing the antenna.
A program plan for the Solar Power Satellite Program is presented. The plan includes research, development, and evaluation phase, engineering and development and cost verification phase, prototype construction, and commercialization. Cost estimates and task requirements are given for the following technology areas: (1) solar arrays; (2) thermal engines and thermal systems; (3) power transmission (to earth); (4) large space structures; (5) materials technology; (6) system control; (7) space construction; (8) space transportation; (9) power distribution, and space environment effects.
The satellite power systems point design concept is described. The concept definition includes satellite, ground and space systems, and their relationships. Emphasis is placed on the definition of the GaAlAs photovoltaic satellite system. The major subsystems of the satellite system including power conversion, power distribution and control, microwave, attitude control and stationkeeping, thermal control, structures, and information management and control are discussed.
An analysis of the solar power satellite system is presented. The satellite solar energy conversion and microwave power transmission systems are discussed including the structure, power distribution, thermal control, and energy storage. Space construction and support systems are described including the work support facilities and construction equipment. An assessment of the space transportation system for the satellite and the ground receiving station is presented.
A systems definition study of the solar power satellite systems is presented. The design and power distribution of the rectenna system is discussed. The communication subsystem and thermal control characteristics are described and a failure analysis performed on the systems is reported.
Elements to be considered in the design of a data bus include: architecture; data rate; modulation, encoding, detection; power distribution requirements; protocol, work structure; bus reliability, maintainability; interterminal transmission medium; cost; and others specific to application. Fiber- optic data bus considerations for a 32 port transmissive star architecture, are discussed in a tutorial format. General optical-waveguide bus concepts, are reviewed. The electrical and optical performance of a 32 port transmissive star bus, and the effects of temperature on the performance of optical-waveguide buses are examined. A bibliography of pertinent references and the bus receiver test results are included.
Top level trade studies are presented, including comparison of solid state and klystron concepts, higher concentration on the solar cells, composite and aluminum structure, and several variations to the reference concept. Detailed trade studies are presented in each of the subsystem areas (solar array, power distribution, structures, thermal control, attitude control and stationkeeping, microwave transmission, and ground receiving station). A description of the selected point design is also presented.
The history of the concept of microwave power beaming to Earth is reviewed with emphasis on transmission frequency selection. Constraints on the system power level results from (1) required rejection of waste heat resulting from inefficiencies in the cover conversion of dc electric power to microwave power; (2) the rf power intensity in the ionosphere; and (3) the effect of sidelobe level on aperture illumination factors. Transmitter arrangement, the power distribution system, attitude control, subarrays, waveguides, and alignment are discussed.
The capabilities of the assembler in installing nonstructural platform systems were assessed. These systems include electrical power distribution, heat transport, command and data signal transmission, and payload data transmission. The effects of including installation of utilities on the assembly process and on the design, operation, and performance of the assembler were evaluated. In addition, any special requirements on the assembler and/or the platform due to the installation of utilities were identified. The procedure followed was to define a set of candidate utility characteristics and installation requirements, define and design installation concepts, and perform an assessment of impacts on the assembler and its operation.
The system components and operation of the space shuttle solid rocket booster (SRB) dewatering set are described. The SRB dewatering set consists of a nozzle plug, control console, remote control unit, power distribution unit, umbilical cable, interconnect cables, and various handling and storage items. The nozzle plug (NP) is a remotely controlled, tethered underwater vehicle that is launched from the retrieval vessel (RV) by a crane, descends down the side of the SRB, and is positioned below the SRB nozzle. A TV camera mounted at the top of the NP central core is used by the control console operator to visually guide the NP during descent and docking. The NP is then driven up and locked into the nozzle. Compressed air is passed through the umbilical from the RV, through the NP and into the SRB motor. The water inside the SRB is expelled causing the SRB to rotate to a near horizontal attitude on the surface of the water.
The several phenomena involved in theoretical prediction of the far-field sound radiation attenuation from an acoustically lined duct were studied. These include absorption by the suppressor, termination reflections, and far-field radiation. Extensive parametric studies show that the suppressor absorption performance can be correlated with mode cut-off ratio or angle of propagation. The other phenomena can be shown to depend explicitly upon mode cut-off ratio. A complete system can thus be generated which can be used to evaluate aircraft sound suppressors and which can be related to the sound source through the cut-off ratio-acoustic power distribution. Although the method is most fully developed for inlet suppressors, several aft radiated noise phenomena are also discussed. This simplified suppressor design and evaluation method is summarized, the recent improvements in the technique are presented, and areas where further refinement is necessary are discussed. Noise suppressor data from engine experiments are compared with the theoretical calculations.
The capabilities and characteristics of the payload carriers developed to provide structural and operational interfaces between the Space Shuttle and the various types of experiments designed to operate in the sortie mode are discussed. The Spacelab is a flexible laboratory system composed of interchangeable elements that can be put together in eight different combinations of pallets and pressurized modules, and provides considerable standard services to users in such areas as equipment installation, power distribution, thermal control, command and data management, software, pointing systems and crew participation. A modular three-axis pointing control system designated the Annular Suspension and Pointing System, is being developed to provide additional pointing capabilities to those payloads that require capabilities not provided by the Spacelab instrument pointing system. Two engineering models of the Spacelab pallet have been designated Orbital Flight Test Pallets which, together with a special experiment support structure, are intended for initial and operational payloads that do not constitute a complete Spacelab mission. The simplest and smallest payload carriers are the Getaway Special cans, intended for small, self-contained, self-sufficient payloads, and the orbiter middeck lockers. In this way, most of the user requirements for Shuttle sortie missions identified to date can be fulfilled.
Space construction systems made feasible by an operational Space Shuttle are discussed with a view toward assembly, installation and construction support equipment. The level of construction capability will be reflected in the number of launches to accomplish a certain mission, either in terms of the mission time line or on the density of packaging in the Orbiter payload bay. It is noted that the development of construction support equipment in zero-gravity simulations should be the most productive initial activity. Crew EVAs, as well as the beam builder, cherrypicker and power distribution buses are covered in detail.
The several phenomena involved in theoretical prediction of the far-field sound radiation attenuation from an acoustically lined duct have been studied. These include absorption by the suppressor, termination reflection, and far-field radiation. Extensive parameteric studies have shown that the suppressor absorption performance can be correlated with mode cut-off ratio or angle of propagation. The other phenomena can be shown to depend explicitly upon mode cut-off ratio. A complete system can thus be generated which can be used to evaluate aircraft sound suppressors and which can be related to the sound source through the cut-off ratio-acoustic power distribution. Although the method is most fully developed for inlet suppressors, several aft radiated noise phenomena will also be discussed. This paper summarized this simplified suppressor design and evaluation method, presents the recent improvements in the technique and discusses areas where further refinement is necessary. Noise suppressor data from engine experiments are compared with the theoretical calculations.
The NASA orbiter spacecraft incorporates a complex array of systems, displays, and controls. The incorporation of discrete dedicated controls into a multifunction display and control system (MFDCS) offers the potential for savings in weight, power, panel space, and crew training time. Technology identified as applicable to a MFDCS is applied to the orbiter orbital maneuvering system (OMS) and the electrical power distribution and control system (EPDCS) to derive concepts for a MFDCS design. Several concepts of varying degrees of performance and complexity are discussed and a suggested concept for further development is presented in greater detail. Both the hardware and software aspects and the human factors considerations of the designs are included.