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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 summary is presented of pertinent research on solar activity variations and climate variations, together with the presentation of an empirical solar/climatic model that attempts to clarify the nature of the relationships.
An interim status briefing concerning the solar energy research is presented. Systems planning, methodology and procedures, which might be applied to the current program are included.
The Skylab field phase in June, August and September of 1973 for the Skylab concentrated atmospheric radiation project provided an opportunity to conduct infrared and solar observations and subsequent calculations beneath the orbiting space vehicle during EREP overpasses. Infrared and solar transmission and absorption properties observed within the atmosphere were compared with EREP experiments, notably the S-191 and S-192. These same observations were later employed in the development and comparison of various atmospheric infrared and solar radiative transfer approximations. Solar radiation observations and calculations in the scattering atmosphere included the 0.4 to 1.1 microns spectral range while infrared observations and calculations covered the spectral band and portions thereof within the 5.0 to 40.0 microns region. Principal conclusions drawn from the solar radiation research and the infrared radiation research are discussed.
Revised measurement and calibration procedures are available. ERDA workshop utilized experience gained in solar cell research to define and explore additional measurement needs of photovoltaic community. Interim measurement procedures previously established were revised and published in manual in addition to other procedures.
Normal isotopic silicon contains 3.05% of Si-30 which transmutes to P-31 after thermal neutron absorption, with a half-life of 2.6 hours. This reaction is used to introduce extremely uniform concentrations of phosphorus into silicon, thus eliminating the areal and spatial inhomogeneities characteristic of chemical doping. Annealing of the lattice damage in the irradiated silicon does not alter the uniformity of dopant distribution. Transmutation doping also makes it possible to introduce phosphorus into polycrystalline silicon without segregation of the dopant at the grain boundaries. The use of neutron transmutation doped (NTD) silicon in solar cell research and development is discussed.
The objectives of and benefits to be derived from a program of solar cycle research are discussed with emphasis on the role space observations will play in this venture. The strategy to be employed in the coming decade is considered as well as crucial missions, experiments, and the theoretical advances required.
Progress in the Progress ceramic materials is reported. Experiments and models for sintering and microstructure evolution are described. Models and data for understanding the kinetics of grain boundary motion and of pore coarsening and new materials for fuel cells and batteries; are developed. New experimental techniques using lasers for forming fine, monosized powders and for forming stable and metastable structures from liquids, and solar materials research are also developed. Colloidal science and ceramics processing are explored; and research programs on the presintering science necessary for controlled green microstructures are outlined.
The advantages of gallium arsenide (GaAs) over silicon (Si) type solar cells are well documented. However, two major disadvantages are weight and cost. Several ideas have recently surfaced that, if successful, will diminish these disadvantages. The CLEFT peeled film technique and the galicon cell are two of the more promising approaches. Low weight, low cost, high efficiency GaAs solar cell research is summarized.
Data on species of interest in the photochemistry of the ozone layer obtained from balloon flights are presented. The flights made use of remote-sensing instruments that took measurements in the wavelength region from the ultraviolet to millimeter wavelengths. Most of the data were obtained with instruments whose readings were in the midinfrared wavelengths. Descriptions are given of the two techniques generally used in this type of research, namely solar absorption and atmospheric emission. The promise that these techniques hold for providing data on the photochemistry of the ozone layer is discussed.
The solar tracking unit was developed to support the Laser Heterodyne Spectrometer (LHS) airborne instrument, but has application to a general class of airborne solar occultation research instruments. The unit consists of a mirror mounted on two gimbals, one of which is hollow. The mirror reflects a 7.6 cm (3.0 in.) diameter beam of sunlight through the hollow gimbal into the research instrument optical axis. A portion of the reflected sunlight is directed into a tracking telescope which uses a four quadrant silicon detector to produce the servo error signals. The colinearity of the tracker output beam and the research instrument optical axis is maintained to better than + or - 1 arc-minute. The unit is microcomputer controlled and is capable of stand alone operation, including automatic Sun acquisition or operation under the control of the research instrument.
It is recommended that a central data catalog and data access network (CDC/DAN) for solar-terrestrial research be established, initially as a NASA pilot program. The system is envisioned to be flexible and to evolve as funds permit, starting from a catalog to an access network for high-resolution data. The report describes the various functional requirements for the CDC/DAN, but does not specify the hardware and software architectures as these are constantly evolving. The importance of a steering committee, working with the CDC/DAN organization, to provide scientific guidelines for the data catalog and for data storage, access, and distribution is also stressed.
Development of high-efficiency multijunction solar cells for concentrator applications is a key step in achieving the goals of the U.S. Department of Energy National Photovoltaics Program. This report summarizes findings of an issue study conducted by the Jet Propulsion Laboratory Photovoltaic Analysis and Integration Center, with the assistance of the Solar Energy Research Institute and Sandia National laboratoies, which surveyed multijunction cell research for concentrators undertaken by federal agencies and by private industry. The team evaluated the potentials of research activities sponsored by DOE and by corporate funding to achieve projected high-efficiency goals and developed summary statements regarding industry expectations. Recommendations are made for the direction of future work to address specific unresolved aspects of multijunction cell technology.
NASA's sub-mm wave technology development program addresses emerging possibilities in spaceborne sensor design for what is one of the few unexplored regions of the spectrum, from 1.0 to 0.1 mm wavelengths. Astrophysics, earth atmosphere research and solar system exploration can all benefit from the development of such sensor capabilities. Technology status evaluations are presented for Shottky-diode and SIS mixers, solid state and backward wave oscillators, intermodulation frequency amplifiers, and digital autocorrelator and acoustooptic spectrometers.
Hybrid indium-tin-oxide (ITO)/InP solar cells are discussed. The cells are constructed by dc magnetron sputter deposition of ITO onto high-quality InP films grown by atmospheric pressure metal-organic vapor-phase epitaxy (APMOVPE). A record efficiency of 18.9 percent, measured under standard Solar Energy Research Institute reporting conditions, has been obtained. The p-InP surface is shown to be type converted, principally by the ITO, but with the extent of conversion being modified by the nature of the sputtering gas. The deposition process, in itself, is not responsible for the type conversion. Dark currents have been suppressed by more than three orders of magnitude by the addition of hydrogen to the sputtering gas during deposition of a thin (5 nm) interface layer. Without this layer, and using only the more usual argon/oxygen mixture, the devices had poorer efficiencies and were unstable. A discussion of associated quantum efficiencies and capacitance/voltage measurements is also presented from which it is concluded that further improvements in efficiency will result from better control over the type-conversion process.
Details of a proposed test program for PV thin-film modules which the Department of Energy has directed the Solar Energy Research Institute (SERI) to prepare are presented. Results of one of the characterization tests that SERI has performed are also presented. The objective is to establish a common approach to testing modules that will be acceptable to both users and manufacturers. The tests include acceptance, qualification, and characterization tests. Acceptance tests verify that randomly selected modules have similar characteristics. Qualification tests are based on accelerated test methods designed to simulate adverse conditions. Characterization tests provide data on performance in a predefined environment.
The current status of indium phosphide solar cell research is reviewed. In the NASA research program, efficiencies of 18.8 percent were achieved for standard n/p homojunction InP cells while 17 percent was achieved for ITO/InP cells processed by sputtering n-type indium tin oxide onto p-type indium phosphide. The latter represents a cheaper, simpler processing alternative. Computer modeling calculations indicate that efficiencies of over 21 percent are feasible. Relatively large area cells are produced in Japan with a maximum efficiency of 16.6 percent.
The tabular calibration method used at the Solar Energy Research Institute (SERI) for primary reference cells is derived and described in detail. An uncertainty analysis shows that the tabular method should have a total uncertainty of + or - 1.0 percent; data from five years of calibrations are then shown to support this analysis. Results from SERI's tabular method are compared with terrestrial calibrations performed by the NASA Lewis Research Center in the late 1970s.
Lunar-based astronomy offers major prospects for solar system research in the coming century. In addition to active advocacy of both ground-based and Lunar-based astronomy, a workshop on the value of asteroids as a resource for man is being organized. The following subject areas are also covered: (1) astrophysics from the Moon (composition and structure of planetary atmospheres); (2) a decade of cost-reduction in Very Large Telescopes (the SST as prototype of special-purpose telescopes); and (3) a plan for development of lunar astronomy.