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Space processing of directionally solidified eutectic-alloy type turbine blades is envisioned as a simple remelt operations in which precast blades are remelted in a preformed mold. Process systems based on induction melting, continuous resistance furnaces, and batch resistance furnaces were evaluated. The batch resistance furnace type process using a multiblade mold is considered to offer the best possibility for turbine blade processing.
A study on the technological feasibility of using solar concentrators for crystal growth and zone refining in space has been performed. Previous studies related to the many aspects of the problem are reviewed. It was concluded from this effort that the technology for fabricating, orbiting, and deploying large solar concentrators has been developed. It was also concluded that the technological feasibility of space processing materials in the focal region of a solar concentrator depends primarily on two factors: (1) the ability of a solar concentrator to provide sufficient thermal energy for the process and (2) the ability of a solar concentrator to provide a thermal environment that is conducive to the processes of interest. The study indicates that solar concentrators of reasonable dimensions can satisfactorily provide both of these factors. This study also indicates that solar concentrators are attractive for space processing from the viewpoint of system specific power and system flexibility.
A technique for the digital simulation of multicorrelated Gaussian random processes is described. This technique is based upon generating discrete frequency functions which correspond to the Fourier transform of the desired random processes, and then using the fast Fourier transform (FFT) algorithm to obtain the actual random processes. The main advantage of this method of simulation over other methods is computation time; it appears to be more than an order of magnitude faster than present methods of simulation. One of the main uses of multicorrelated simulated random processes is in solving nonlinear random vibration problems by numerical integration of the governing differential equations. The response of a nonlinear string to a distributed noise input is presented as an example.
The attitude of the balloon system is determined as a function of time if: (a) a method for simulating the motion of the system is available, and (b) the initial state is known. The initial state is obtained by fitting the system motion (as measured by sensors) to the corresponding output predicted by the mathematical model. In the case of the LACATE experiment the sensors consisted of three orthogonally oriented rate gyros and a magnetometer all mounted on the research platform. The initial state was obtained by fitting the angular velocity components measured with the gyros to the corresponding values obtained from the solution of the math model. A block diagram illustrating the attitude determination process employed for the LACATE experiment is shown. The process consists of three essential parts; a process for simulating the balloon system, an instrumentation system for measuring the output, and a parameter estimation process for systematically and efficiently solving the initial state. Results are presented and discussed.
The need for rapid, cost-effective extraction of useful information from vast quantities of multispectral imagery available from aircraft or spacecraft has resulted in the design, implementation and application of a state-of-the-art processing system known as IMAGE 100. Operating on the general principle that all objects or materials possess unique spectral characteristics or signatures, the system uses this signature uniqueness to identify similar features in an image by simultaneously analyzing signatures in multiple frequency bands. Pseudo-colors, or themes, are assigned to features having identical spectral characteristics. These themes are displayed on a color CRT, and may be recorded on tape, film, or other media. The system was designed to incorporate key features such as interactive operation, user-oriented displays and controls, and rapid-response machine processing. Owing to these features, the user can readily control and/or modify the analysis process based on his knowledge of the input imagery. Effective use can be made of conventional photographic interpretation skills and state-of-the-art machine analysis techniques in the extraction of useful information from multispectral imagery. This approach results in highly accurate multitheme classification of imagery in seconds or minutes rather than the hours often involved in processing using other means.
The investigations of directional solidification have indicated the necessity of establishing a secure foundation in earth-based laboratory processing in order to properly assess low-gravity processing. Emphasis was placed on evaluating the regularity of microstructure of the rod-like eutectic Al-Al3Ni obtained under different conditions of growth involving the parameters of thermal gradient, solidification rate, and interfacial curvature. In the case of Al-Al3Ni, where the Al3Ni phase appears as facets rods, solidification rate was determined to be a controlling parameter. Zone melting of thin eutectic films showed that for films of the order of 10 to 20 micrometers thick, the extra surface energy appears to act to stabilize a regular microstructure. The results suggest that the role of low-gravity as provided in space-laboratory processing of materials is to be sought in the possibility of generating a higher thermal gradient in the solidifying ingot for a given power input-output arrangement than can be obtained under normal one-g processes.
Plant construction costs and manufacturing costs were estimated for the production of solar-grade silicon by the reduction of silicon tetrachloride in a fluidized bed of seed particles, and several modifications of the iodide process using either thermal decomposition on heated filaments (rods) or hydrogen reduction in a fluidized bed of seed particles. Energy consumption data for the zinc reduction process and each of the iodide process options are given and all appear to be acceptable from the standpoint of energy pay back. Information is presented on the experimental zinc reduction of SiCl4 and electrolytic recovery of zinc from ZnCl2. All of the experimental work performed thus far has supported the initial assumption as to technical feasibility of producing semiconductor silicon by the zinc reduction or iodide processes proposed. The results of a more thorough thermodynamic evaluation of the iodination of silicon oxide/carbon mixtures are presented which explain apparent inconsistencies in an earlier cursory examination of the system.
An experimental drop tower package was designed and built for use in a drop tower. This effort consisted of a thermal analysis, container/heater fabrication, and assembly of an expulsion device for rapid quenching of heated specimens during low gravity conditions. Six gallium bismuth specimens with compositions in the immiscibility region (50 a/o of each element) were processed in the experimental package: four during low gravity conditions and two under a one gravity environment. One of the one gravity processed specimens did not have telemetry data and was subsequently deleted for analysis since the processing conditions were not known. Metallurgical, Hall effect, resistivity, and superconductivity examinations were performed on the five specimens. Examination of the specimens showed that the gallium was dispersed in the bismuth. The low gravity processed specimens showed a relatively uniform distribution of gallium, with particle sizes of 1 micrometer or less, in contrast to the one gravity control specimen. Comparison of the cooling rates of the dropped specimens versus microstructure indicated that low cooling rates are more desirable.
A survey of the economics of space materials processing has been performed with the objectives of identifying those areas of space materials processing that give preliminary indication of significant economic potential, and to identify possible approaches to quantify the economic potential. It is concluded that limited economic studies have been performed to date, primarily in the area of the processing of inorganic materials, but that the economics of space processing of biological material has not received adequate attention. Specific studies are recommended to evaluate the economic impact of human lymphocyte subgroup separation on organ transplantation, and on the separation and concentration of urokinase producing cells.
A proof-of-concept solar cell process has been developed that is adaptable to automation. This involved the development of a new contact system, a new antireflection coating system, a drift field cell design and a new contoured surface treatment. All these processes are performed without the use of vacuum chambers and expensive masking techniques, thus providing the possibility of reduced costs by automation using conventional semiconductor processing machinery. The contacts were printed on the cells by conventional silk screen machinery. The P(+) back field was formed by diffusing in aluminum from a printed aluminum back contact. The antireflection coating was formed by spinning on and baking a TiO2-SiO2 glass film. Air-mass-zero efficiencies of over 10% were achieved using this completely vacuum-free process.
The Federal Systems Division of IBM has developed an image processing facility to experimentally process, view, and record digital image data. This facility has been used to support LANDSAT digital image processing investigations and advanced image processing research and development. A brief description of the facility is presented, some techniques that have been developed to correct the image data are discussed, and some results obtained by users of the facility are described.
An overview is given of the definition of research requirements and derivation of engineering design requirements for a group of 77 representative applications of space processing. Representative requirements are documented for applied research in space on biological processes, chemical/fluid phenomena, solidification processes, and glass/ceramics processes. Design requirements for payload equipment to accommodate these research requirements are presented in engineering terms, such as power requirements, schematic diagrams, etc. In addition, a summary of the 77 applied research topics is included.
The results of a study conducted to determine the role space processing or materials research in space plays in the superconductor and electrical contact industries are presented. Visits were made to manufacturers, users, and research organizations connected with these products to provide information about the potential benefits of the space environment and to exchange views on the utilization of space facilities for manufacture, process development, or research. In addition, space experiments were suggested which could result in improved terrestrial processes or products. Notable examples of these are, in the case of superconductors, the development of Nb-bronze alloys (Tsuei alloys) and, in the electrical contact field, the production of Ag-Ni or Ag-metal oxide alloys with controlled microstructure for research and development activities as well as for product development. A preliminary experimental effort to produce and evaluate rapidly cooled Pb-Zn and Cu-Nb-Sn alloys in order to understand the relationship between microstructure and superconducting properties and to simulate the fine structure potentially achievable by space processing was also described.
The NASA Space Processing Program was initiated to develop uses of space flight that will support research efforts and manufacturing operations on the ground by processing materials in space. It is expected that the unique conditions that are available in space will provide a basis for a wide variety of economically beneficial services to science and industry in fields such as metallurgy, electronic materials, glass technology, fluid physics and chemistry, and in biological material preparation as well. Plans are described for developing payload equipment to implement materials processing experiments on the missions of the space transportation system (STS). This equipment is intended to support a diversified program of NASA-sponsored materials processing experiments by all classes of scientists, as well as pilot activities by non-NASA sponsors.
The integrated payload and mission planning process for STS payloads was defined, and discrete tasks which evaluate performance and support initial implementation of this process were conducted. The scope of activity was limited to NASA and NASA-related payload missions only. The integrated payload and mission planning process was defined in detail, including all related interfaces and scheduling requirements. Related to the payload mission planning process, a methodology for assessing early Spacelab mission manager assignment schedules was defined.
The manner in which the weightless, containerless nature of in-space processing can be successfully utilized to improve the quality of infrared transmitting chalcogenide glasses is determined. The technique of space processing chalcogenide glass was developed, and the process and equipment necessary to do so was defined. Earthbound processing experiments with As2S3 and G28Sb12Se60 glasses were experimented with. Incorporated into these experiments is the use of an acoustic levitation device.
The procedure for analyzing thermochemical water-splitting processes using the figure of merit is expanded to include individual stage efficiencies and loss coefficients. The use of these quantities to establish the thermodynamic insufficiencies of each stage is shown. A number of processes are used to illustrate these concepts and procedures and to demonstrate the facility with which process steps contributing most to the cycle efficiency are found. The procedure allows attention to be directed to those steps of the process where the greatest increase in total cycle efficiency can be obtained.
The Planetary Geology Field Conference on Aeolian Processes was organized at the request of the Planetary Geology Program office of the National Aeronautics and Space Administration to bring together geologists working on aeolian problems on earth and planetologists concerned with similar problems on the planets. Abstracts of papers presented at the conference are arranged herein by alphabetical order of the senior author. Papers fall into three broad categories: (1) Viking Orbiter and Viking Lander results on aeolian processes and/or landforms on Mars, (2) laboratory results on studies of aeolian processes, and (3) photogeology and field studies of aeolian processes on Earth.