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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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At least 379 records · Page 21
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NASA NTRS1983

Remote sensing and vegetation stress detection - Problems and progress

Although considerable progress has been made in applying remote sensing technology to vegetation monitoring, considerable problems still exist in the improvement of techniques for crop type discrimination, stress detection on a large scale, and stress quantification. In this paper, some of the problems remaining in the operational use of remote sensing technology for vegetation stress detection are discussed, and directions in which some of these problems might be solved are proposed.

Duggin, M. J.↗
NASA NTRS1984

Progressive autonomy

The present investigation is concerned with the evolution of a space station in terms of the progression of autonomy, as systems perspectives and architectural concepts permit. The distinction between automation and autonomy is considered along with the evolution of autonomy, and the evolution of automation in station operations. Attention is given to the startup of a complex technological system, aspects of station control, questions of crew operational support, factors regarding the habitability of a space station, system design philosophy for autonomy, evolvability, latent capability, stage commonality, and multiple modularity. It is concluded that an evolutionary space station operating over a period of 10-20 years with a great increase in capability over that time will require a design philosophy which is more flexible and open-ended than for previous space systems.

Anderson, J. L.↗
NASA NTRS1984

Progress in natural laminar flow research

For decades, since the earliest attempts to obtain natural laminar flow (NLF) on airplanes, three classical objections to its practicality have been held in the aeronautical community. These objectives concerned first, the capability to manufacture practical airframe surfaces smooth enough for NLF; second, the apparent inherent instability and sensitivity of NLF; and third, the accumulation of contamination such as insect debris in flight. This paper explains recent progress in our understanding of the achieveability and maintainability of NLF on modern airframe surfaces. This discussion explains why previous attempts to use NLF failed and what has changed regarding the three classical objections to NLF practicality. Future NASA research plans are described concerning exploring the limits of NLF usefulness, production tolerances, operational considerations, transition behavior and measurement methods, and NLF design applications.

Holmes, B. J.↗
NASA NTRS1984

Progress in optical parametric oscillators

It is pointed out that tunable coherent sources are very useful for many applications, including spectroscopy, chemistry, combustion diagnostics, and remote sensing. Compared with other tunable sources, optical parametric oscillators (OPO) offer the potential advantage of a wide wavelength operating range, which extends from 0.2 micron to 25 microns. The current status of OPO is examined, taking into account mainly advances made during the last decade. Attention is given to early LiNbO3 parametric oscillators, problems which have prevented wide use of parametric oscillators, the demonstration of OPO's using urea and AgGaS2, progress related to picosecond OPO's, a breakthrough in nanosecond parametric oscillators, the first demonstration of a waveguide and fiber parametric amplification and generation, the importance of chalcopyrite crystals, and theoretical work performed with the aim to understand the factors affecting the parametric oscillator performance.

Fan, Y. X.↗
NASA NTRS1984

Progress in net shape fabrication of alpha sic turbine components

An update of the status of ceramic component development of the AGT Programs is presented. Activity on AGTO Program focussed on the following: successful transition from the prototype to engine configuration rotor, investigation of alternate rotor molding techniques, and completion of scroll assemblies. Progress on the Garrett AGT Program was highlighted by the introduction of plastic molding and extrusion to parts which were previously fabricated by slip casting and isopressing respectively.

Sweeting, T. B.↗
NASA NTRS1984

The Magneto-optical Filter, Working Principles and Recent Progress

The Magneto-Optical Filter is described which allows simultaneous magnetic and velocity measurements (in both imaging and non-imaging modes) without the need for a spectrograph. In this way the stability and alignment problems of the spectrograph are completely overcome. Its major advantages are: wavelength absolute reference and stability, high signal to noise ratio and independence of the transmission profile from the incidence angle of the solar beam. It is an imaging instrument allowing high wave number analysis in the solar oscillation spectrum and a continuous monitoring of the image position through the chromospheric facular structures. The apparatus in use at Mt. Wilson is assembled in a modular form. The most important part of it is a glass cell containing the sodium vapor. The filter is easy to use but the cell is not easy to construct in an optimal way. The technology is in progress both to use Na and K together and to prevent the windows from becoming coated during a long-term operation.

Cacciani, A.↗
NASA NTRS1985

NASA R and T aerospace plane vehicles: Progress and plans

Progress made in key technologies such as materials, structures, aerothermodynamics, hypersonic aerodynamics, and hypersonic airbreathing propulsion are reported. Advances were made in more generic, areas such as active controls, flight computer hardware and software, and interdisciplinary analytical design methodology. These technology advances coupled with the development of and experiences with the Space Shuttle make feasible aerospace plane-type vehicles that meet the more demanding requirements of various DOD missions and/or an all-weather Shuttle II with reduced launch costs. Technology needs and high payoff technologies, and the technology advancements in propulsion, control-configured-vehicles, aerodynamics, aerothermodynamics, aerothermal loads, and materials and structures were studied. The highest payoff technologies of materials and structures including thermal-structural analysis and high temperature test techniques are emphasized. The high priority technology of propulsion, and plans, of what remains to be done rather than firm program commitments, are briefly discussed.

Dixon, S. C.↗
NASA NTRS1984

The Sondrestrom radar: Progress and proposed upgrades for ST work

The capabilities and limitations of the Sondrestrom Radar for stratosphere-troposphere ST observations were previously presented. Recent progress and proposed upgrades are summarized. During the first year of operation (April 1983 to April 1984) there was only one ST experiment, mainly with the objective of evaluating the site and determining that the hardare and software were still operational after the radar's move from Alaska. The Sondrestrom site has about the same degree of ground clutter as the former Chatanika site and the data appear to be similar. The radar's operation continues to be incoherent-scatter observations of the ionosphere. The main radar parameters are summarized.

Watkins, B. J.↗
NASA NTRS1985

Progress report - Advanced cryogenic OTV engine technology

New technologies for space-based, reusable, throttleable, cryogenic orbit transfer propulsion are being evaluated. A variable-thrust (200 to 3000 lbF), 2000 psi chamber pressure, LO2/LH2 engine has been selected to demonstrate the 20-hour, 500-restart life goal, and a specific impulse in excess of 480 lbF-sec/lbM. The results of recent vehicle-engine integration analyses and the progress in design, fabrication, and testing are provided. Emphasis is placed on the following technology areas being investigated in support of the advanced engine design: LOX hydrostatic bearings; burn-resistant materials for high-pressure GOX turbines and valves; high surface-low flux annular combustion chambers for the dual propellant expander cycle; improved cooling approaches for high-pressure combustion chambers, new concepts in integrated controls; and engine health diagnostics.

Schoenman, L.↗
NASA NTRS1985

Progressive damage, fracture predictions and post mortem correlations for fiber composites

Lewis Research Center is involved in the development of computational mechanics methods for predicting the structural behavior and response of composite structures. In conjunction with the analytical methods development, experimental programs including post failure examination are conducted to study various factors affecting composite fracture such as laminate thickness effects, ply configuration, and notch sensitivity. Results indicate that the analytical capabilities incorporated in the CODSTRAN computer code are effective in predicting the progressive damage and fracture of composite structures. In addition, the results being generated are establishing a data base which will aid in the characterization of composite fracture.

Source record↗
NASA NTRS1985

Discussion on the progress and future of satellite communication (Japan)

The current status of communications satellite development in Japan is presented. It is shown that beginning with research on satellite communucations in the late 1950's, progress was made in the areas of communications, remote sensing, and technology experimentation. The current status of communication satellites is presented, stressing development in the areas of CFRP construction elements, the use of LSI and MIC circuits, advanced multibeam antenna systems, Ku and Ka band transmission systems, and the shift to small-scale earth stations. Methods for reducing costs and increasing transmission efficiency are shown. The technical specifications of all satellite projects currently under development are given. Users of Japanese communications satellite are presented.

Ogata, M.↗
NASA NTRS1985

Recent cryocooler progress in Japan

The progress of cryocoolers and related devices in Japan is reviewed. The Japanese National Railways has developed the light weight 4 K on-board refrigerators since 1977 as part of the MAGLEV train program. Superconducting and cryogenic fundamental technology was examined which included high performance cryocooler, magnetic refrigerator and superfluid refrigeration. Space cryogenics such as the cooling systems of IR-detectors was studied. Cryocooler for special applications such as cryopump, NMR-CT and JJ devices was investigated. Compact heat exchangers, high performance regenerators and reliable compressors are investigated as a critical component technology.

Matsubara, Y.↗
NASA NTRS1986

Progress in the Lewis Research Center Altitude Wind Tunnel (AWT) Modeling Program

The rehabilitation of the Altitude Wind Tunnel (AWT) at the NASA Lewis Research Center is under study with the goal of providing a modern subsonic wind tunnel for conducting propulsion system/airframe integration, isolated propulsion system, propulsion acoustics and adverse weather tests. Because of the increased Mach number capability (from Mach 0.6 to 0.9 plus) and the incorporation of acoustic and adverse weather capabilities into an existing tunnel, the AWT rehabilitation represents a significant technical challenge. In order to reduce the risk associated with such an undertaking, and extensive AWT modeling program is being conducted to guide and verify the tunnel design. Significant findings and progress in this modeling program are the subject of this paper.

Ciepluch, C. C.↗
NASA NTRS1985

Aeroelasticity at the NASA Langley Research Center Recent progress, new challenges

Recent progress in aeroelasticity, particularly at the NASA Langley Research Center is reviewed to look at the questions answered and questions raised, and to attempt to define appropriate research emphasis needed in the near future and beyond. The paper is focused primarily on the NASA Langley Research Center (LaRC) Program because Langley is the lead NASA center for aerospace structures research, and essentially is the only one working in depth in the area of aeroelasticity. Historical trends in aeroelasticity are reviewed broadly in terms of technology and staffing particularly at the LaRC. Then, selected studies of the Loads and Aeroelasticity Division at LaRC and others over the past three years are presented with attention paid to unresolved questions. Finally, based on the results of these studies and on perceptions of design trends and aircraft operational requirements, future research needs in aeroelasticity are discussed.

Hanson, P. W.↗
NASA NTRS1984

Recent progress in the measurement of temperature and salinity by optical scattering

Recent progress is described in the use of Brillouin and Raman scattering for the measurement of temperature and salinity in the ocean. The use of Brillouin scattering is described for the measurement of the sound velocity, and the use of Raman scattering is described for the independent measurement of the temperature and salinity. Coupling these techniques permits the assessment of both temperature and salinity. The experimental techniques are described together with the results of recent experiments and an assessment of the errors to be expected.

Collins, D. J.↗
NASA NTRS1985

Rheologies of H2O ices Ih, II, and III at high pressures - A progress report

Ordinary hexagonal ice (ice Ih) represents the stable crystalline form of H2O on the earth's surface. It is known that ice exists elsewhere in the solar system. Thus, several of the moons of Saturn and Jupiter are composed predominately of H2O and their surface temperatures are about 75 and 100 K. The pressures in the interior of some of the larger of the moons may be as high as 3 GPa. The involved pressures and temperatures extend far beyond the conditions over which the rheological laws for ice Ih can be confidently extrapolated. It is, therefore, necessary to obtain information regarding the rheologies of H2O ices in pressure and temperature ranges which had not yet been previously considered. Since 1981, over 100 triaxial compression tests have been conducted over a wide range of temperatures (77 to 258 K) and pressures (0.1 to 350 MPa). The present paper provides a progress report of these experiments.

Kirby, S. H.↗
NASA NTRS1986

Progress in the Lewis Research Center Altitude Wind Tunnel (AWT) modeling program

The rehabilitation of the AWT at the NASA Lewis Research Center is under study with the goal of providing a modern subsonic wind tunnel for conducting propulsion system/airframe integration, isolated propulsion system, propulsion acoustics and adverse weather tests. Because of the increased Mach number capability (from Mach 0.6 to 0.9 plus) and the incorporation of acoustic and adverse weather capabilities into an existing tunnel, the AWT rehabilitation represents a significant technical challenge. In order to reduce the risk associated with such an undertaking, an extensive AWT modeling program is being conducted to guide and verify the tunnel design. Significant findings and progress in this modeling program are the subject of this paper.

Ciepluch, C. C.↗
NASA NTRS1986

Flight research on natural laminar flow nacelles - A progress report

This paper presents a progress report on an ongoing flight experiment for natural laminar flow nacelles. The results given herein were obtained during the first phase of the experiment, in which an instrumented natural laminar flow nacelle fairing was flight tested in the presence of turbofan engine noise and a controlled noise source. The results indicate that with the controlled noise source off, natural laminar flow was measured as far aft as 37 percent of the fairing length. The transition front was irregular in contour, and the extent of natural laminar flow was significantly affected by the relative flow angle for the fairing. In addition to these test results, the paper discusses the results of some recent computational analyses to predict pressure distributions and transition location, and to explain some of the data trends. Comparisons between measured and predicted data indicate that the analytical methods successfully predicted trends for the baseline (no controlled noise source) studies.

Hastings, E. C., Jr.↗