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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Future long-range transports - Prospects for improved fuel efficiency

A status report is provided on current thinking concerning potential improvements in fuel efficiency and possible alternate fuels. Topics reviewed are: historical trends in airplane efficiency; technological opportunities including supercritical aerodynamics, vortex diffusers, composite materials, propulsion systems, active controls, and terminal-area operations; unconventional design concepts, and hydrogen-fueled airplane.

Nagel, A. L.↗
NASA NTRS1975

Observing prospects for Halley's comet

The expected path and brightness development of Halley's comet soon before and after its perihelion on February 9, 1986 are described. It is concluded that the comet will prove disappointing to most U.S. observers, since it is not expected to equal Kohoutek in peak magnitude (and since this latter comet was disappointing to the general public). Moreover, Halley's comet will be brightest (3rd magnitude) in the southern hemisphere, and increased outdoor lighting by the year 1986 will probably obscure its tail near cities.

Roosen, R. G.↗
NASA NTRS1974

Electric propulsion - Past history and future prospects

Studies of feasibility and flight mechanics of electric propulsion systems began around 1946. Conceptual systems design started in 1954, experimental developments in 1958; flight tests in 1964 and 1970 proved the functioning of electric thrusters in space. Further development of ion thruster systems has concentrated on bombardment ionization in the U.S., and on radiofrequency, bombardment, and surface contact ionization in West Germany, Great Britain, France and Russia. Electrothermal, plasma, and colloid thruster development has been pursued in many contries. Electric thrusters were used successfully during past years for satellite attitude control, and for prime propulsion of the Russian spacecraft Yantar. Further applications for attitude and position control of satellites are planned. Studies are presently underway for solar electric missions to planets, planetary moons, comets, asteroids, and toward the sun, and also for missions in near-earth space involving transfer, servicing, and repair of orbiting spacecraft.

Stuhlinger, E.↗
NASA NTRS1975

Shadowgraphs of air flow over prospective space shuttle configurations at Mach numbers from 0.8 to 1.4

Shadowgraphs of five space shuttle launch configurations are presented. The model was a 4 percent-scale space shuttle vehicle, tested in the 11- by 11-foot Transonic Wind Tunnel at Ames Research Center. The Mach number was varied from 0.8 to 1.4 with three angles of sideslip (0 deg, 5 deg and -5 deg) that were used in conjunction with three angles of attack (4 deg, -4 deg, and 0 deg). The model configurations included both series-burn and parallel-burn configurations, two canopy configurations, two positions of the orbiter nose relative to the HO tank nose, and two HO tank nose-cones angles (15 deg and 20 deg). The data consist entirely of shadowgraph photographs.

Dods, J. B., Jr.↗
NASA NTRS1976

The prospects for life on Mars: A pre-Viking assessment

Mariner 9 provided a reinterpretation of several historical claims for Martian biology, and permitted an important further characterization of the environmental constraints on possible Martian organisms. Four classes of conceivable Martian organisms are identified, depending on the environmental temperature, T, and water activity, aw: Class 1, high T, high aw; Class 2, low T, high aw; Class 3, high T, low aw; and Class 4, low T, low aw. Organisms which extract their water requirements from hydrated minerals or from ice are considered possible on Mars, and the high ultraviolet flux and low oxygen partial pressure are considered to be negligible impediments to Martian biology. Large organisms are not only possible on Mars, they may be favored. The surface distribution of Martian organisms and future search strategies for life on Mars are discussed.

Sagan, C.↗
NASA NTRS1976

The prospects for life on Mars - A pre-Viking assessment

The paper considers implications of the Mariner 9 findings for the investigation of Martian biology in the next decade, beginning with the Viking mission. Previous claims for observations of Martian biological activity are reviewed and refuted or reinterpreted. The question is raised of whether there are combinations of environmental temperature and water activity on Mars that are suitable for a conceivable Martian biology. Four possible classes of Martian organisms associated with temperature/water ecological niches in the external environment are proposed: organisms requiring high temperatures and high water activity, those inhabiting niches with low temperatures and high water activity, those inhabiting niches of high temperature and low water activity, and those which can survive under conditions of low temperature and low water activity. It is noted that organisms of the last two classes may extract water from minerals or from ice and may be of large dimensions. The possible surface distribution of Martian organisms is discussed along with future search strategies for life on Mars.

Sagan, C.↗
NASA NTRS1976

Prospective markets and design concepts for civilian remotely piloted aircraft

This paper summarizes a study that examines the technical, economic, and environmental aspects of remotely piloted vehicles (RPVs) in the civil environment. A market survey was conducted in which 35 civil applications of RPVs were identified. For a number of these uses, vehicle and system concepts were defined, benefit and cost comparisons were made with present methods, and the influence of safety and environmental implications was assessed. The results suggest a sizable potential demand for the use of RPVs in the civil sector, and some of the applications show promising cost savings over established methods. A focussed technology effort could provide the safety assurances needed for routine civilian operation of RPVs.

Nelms, W. P., Jr.↗
NASA NTRS1976

Use of satellite pictures for determining major shield fractures relevant for ore prospecting, northern Finland

The author has identified the following significant results. A combined analysis of LANDSAT 1 imagery, aeromagnetic and other maps, and aerial photos has revealed a dense network of bedrock fractures in northern Finland. They form several fracturing zones, which obviously represent surficial manifestations of major fractures. The fractures follow, in general, the eight main trends of crustal shear characteristics of the Baltic Shield, but show distinct deviations from them in detail. The major fracture zones divide the bedrock into a mosaic of polygonal blocks, which in many cases coincide with the main rock units of the area and are characterized by different patterns of internal fracturing. Known mineralizations show a tendency to concentrate along the fracture zones. Optical filtering of original LANDSAT images might provide a rapid tool for the analysis of major structural trends in extensive areas such as shields or entire continents.

Tuominen, H. V.↗
NASA NTRS1977

Bioprocessing: Prospects for space electrophoresis

The basic principles of electrophoresis are reviewed in light of its past contributions to biology and medicine. The near-zero gravity environment of orbiting spacecraft may present some unique advantages for a variety of processes, by abolishing the major source of convection in fluids. As the ground-based development of electrophoresis was heavily influenced by the need to circumvent the effects of gravity, this process should be a prime candidate for space operation. Nevertheless, while a space facility for electrophoresis may overcome the limitations imposed by gravity, it will not necessarily overcome all problems inherent in electrophoresis. These are, mainly, electroosmosis and the dissipation of the heat generated by the electric field. The NASA program has already led to excellent coatings to prevent electroosmosis, while the need for heat dissipation will continue to impose limits on the actual size of equipment. It is also not excluded that, once the dominant force of gravity is eliminated, disturbances in fluid stability may originate from weaker forces, such as surface tension.

Bier, M.↗
NASA NTRS1977

Alternate aircraft fuels: Prospects and operational implications

The potential use of coal-derived aviation fuels was assessed. The studies addressed the prices and thermal efficiencies associated with the production of coal-derived aviation kerosene, liquid methane and liquid hydrogen and the air terminal requirements and subsonic transport performance when utilizing liquid hydrogen. The fuel production studies indicated that liquid methane can be produced at a lower price and with a higher thermal efficiency than aviation kerosene or liquid hydrogen. Ground facilities of liquefaction, storage, distribution and refueling of liquid hydrogen fueled aircraft at airports appear technically feasibile. The aircraft studies indicate modest onboard energy savings for hydrogen compared to conventional fuels. Liquid hydrogen was found to be superior to both aviation kerosene and liquid methane from the standpoint of aircraft engine emissions.

Witcofski, R. D.↗
NASA NTRS1976

Prospects for pipeline delivery of hydrogen as a fuel and as a chemical feedstock

The possibility of using hydrogen for storing and carrying energy obtained from nonfossil sources such as nuclear and solar energy is examined. According to the method proposed, these nonfossil raw energy sources will be used to obtain hydrogen from water by three basically distinct routes: (1) electrical generation followed by electrolysis; (2) thermochemical decomposition; and (3) direct neutron or ultraviolet irradiation of hydrogen bearing molecules. The hydrogen obtained will be transmitted in long-distance pipelines, and distributed to all energy-consuming sectors. As a fuel gas, hydrogen has many qualities similar to natural gas and with only minor modifications, it can be transmitted and distributed in the same equipment, and can be burned in the same appliances as natural gas. Hydrogen can also be used as a clean fuel (water is the only combustion product) for automobiles, fleet vehicles, and aircraft.

Gregory, D. P.↗
NASA NTRS1976

Technical prospects for commercial and residential distribution and utilization of hydrogen

Various investigators have assumed that hydrogen will be compatible with conventional gas delivery systems and that, with minor modifications, hydrogen can be utilized in existing equipment for heating and cooking. The paper addresses some of the issues of concern in the compatibility of natural gas systems with hydrogen and hydrogen mixtures and identifies areas for which tests, research, or development are appropriate. Requirements to be met by atmospheric burners built for most commercial and residential gas appliances are discussed. Expected modifications to appliances for satisfactory operation with hydrogen are closing the primary air shutters, replacing the burners, adjusting the appliance gas regulator for proper delivery pressure, and possibly replacing the gas regulator or its vent.

Pangborn, J.↗
NASA NTRS1977

Prospects for cosmic X-ray spectroscopy

Attention is given to solar X-ray spectroscopy, the determination of the ionization of gas and geometrical distribution of gas in binary X-ray sources, and the investigation of extragalactic X-ray sources. The HEAO-B satellite which carries a focusing X-ray telescope with three powerful spectrometers is considered.

Mccray, R.↗
NASA NTRS1977

Long-term prospects for developments in space: A scenario approach

Long-term plans for future NASA programs are reported, and some of the following topics are discussed in detail: (1) systematic formulation of space scenarios; (2) the basic international context; (3) potential 21st century space developments; (4) space vehicle developments; and (5) future exploration.

Brown, W. M.↗