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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 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Radioactive waste disposal via electric propulsion

It is shown that space transportation is a feasible method of removal of radioactive wastes from the biosphere. The high decay heat of the isotopes powers a thermionic generator which provides electrical power for ion thrust engines. The massive shields (used to protect ground and flight personnel) are removed in orbit for subsequent reuse; the metallic fuel provides a shield for the avionics that guides the orbital stage to solar system escape. Performance calculations indicate that 4000 kg. of actinides may be removed per Shuttle flight. Subsidiary problems - such as cooling during ascent - are discussed.

Burns, R. E.↗
NASA NTRS1978

Escort - A data acquisition and display system to support research testing

A combination of a central minicomputer and test-site microcomputers has been adopted to provide on-line data acquisition and display service for a large number of different research programs. By integrating the data acquisition and recording functions in the minicomputer/microcomputer system, rapidly updated displays of selected data in terms of engineering units may be obtained. The system described here is primarily designed for steady-state test conditions, but may also provide data on slow transients associated with changing experimental conditions. Application of the system to full-scale jet engine tests, ion thruster assessments and anechoic chamber analyses are mentioned.

Miller, R. L.↗
NASA NTRS1978

Estimates of ground-level mercury vapor concentrations from postulated launch-pad accidents of NASA space transportation systems

NASA has considered the use of mercury ion bombardment engines as extra-terrestrial propulsion systems where low thrust must be provided for long periods of time. However, the mercury fuel in these engines may pose a hazard if it is accidentally released to the troposphere. A description is presented of diffusion-model estimates of maximum 10-minute and 24-hour ground-level concentrations that could result from the accidental release of mercury from Titan/Centaur and Space Shuttle/Tug transportation systems. Three types of accidental release modes have been considered in the concentration calculations. For all three modes, the diffusion-model calculations were made for a variety of meteorological conditions in an effort to obtain estimates of the maximum credible concentrations under 'worst-case' conditions.

Dumbauld, R. K.↗
NASA NTRS1980

Comets and cometary missions

The paper deals with the planning phase of a combined NASA/ESA dual comet mission to the two periodic comets, P/Halley and P/Temple-2. The project is planned for a FY 81 start. If approved, the launch would occur in July or August 1985, using Shuttle IUS twin stage. The solar powered ion propulsion engine will provide continuous thrust virtually throughout the three-year flight until the P/Temple-2 rendezvous in July 1988. En route to the Temple-2 rendezvous, an ESA Halley probe will be deployed to encounter Halley about 73 days before perihelion, when the heliocentric distance of Halley is about 1.5 AU.

Mendis, D. A.↗
NASA NTRS1993

Spectroscopic investigations of beam-plasma interactions in an ion plume

We report the results of spectroscopic investigations of beam-plasma interactions in the plume from a 3 cm ion source operated on argon. Ion-electron, ion-neutral, and electron-neutral scattering are identified by studying the dependence of neutral and ion emission intensities on chamber pressure and mass flow rate, and by analyzing the emission lineshapes at a non-orthogonal angle to the plume axis. Through the Doppler shift, we are able to separate contributions from fast beam ions and fast charge-exchange neutrals on the one hand, and of slow neutrals and slow ions on the other. We discuss the application of this new technique to the characterization of beam plasma interactions in the downstream region of ion thruster engines, and its potential for identifying the processes which lead to grid erosion.

Ruyten, W. M.↗
NASA NTRS1982

The 1982 Aeronautics and Space Highlights

This video includes STS 3 & 4, Challenger completed, unmanned launches, the Hubble Space Telescope, Pioneers 8 & 9 encounter, Mars Pictures, Landsat 4, wind energy, ion-electric engines, solar powered medical system, medical image analysis, rotor systems research aircraft, XV-15, propfan research, aircraft icing studies, and Oshkosh Sirshow.

Source record↗
NASA NTRS2000

The Use of Environmental Test Facilities for Purposes Beyond Their Original Design

Increasing demands from space flight project offices are requiring environmental testing facilities to become more versatile with increased capabilities. At the same time, maintaining a cost-effective approach to test operations has driven efforts to use these facilities for purposes beyond their original design. This paper presents an overview of the Jet Propulsion Laboratory's efforts to provide JPL's space flight projects with test facilities to meet unique test requirements and to serve the needs of selected outside customers. The large number of recent Mars Missions, including the Mars Pathfinder project, have required testing of components and systems in a Martian surface environment in facilities originally designed for deep space testing. The unique problems associated with performing these tests are discussed, along with practical solutions. Other unique test requirements are discussed including the use of space simulation chambers for testing high altitude balloon gondolas and the use of vacuum chambers for system level test firing of an ion propulsion engine.

Fisher, Terry C.↗
NASA NTRS2002

Stirring Up an Elastic Fluid: Critical Viscosity of Xenon-2 (CVX-2)

Whipped cream stays in place even when turned upside down. Yet it readily flows through the nozzle of a spray can to reach the dessert plate. This demonstrates the phenomenon of shear thinning that is important to many industrial and physical processes. Paints, film emulsions, and other complex solutions that are highly viscous under normal conditions but become thin and flow easily under shear forces. A simple fluid, such as water, does not exhibit shear thinning under normal conditions. Very close to the liquid-vapor critical point, where the distinction between liquid and vapor disappears, the fluid becomes more complex and is predicted to display shear thinning. At the critical point, xenon atoms interact over long distances in a classical model of cooperative phenomena. Physicists rely on this system to learn how long-range order arises. The Critical Viscosity of Xenon Experiment (CVX-2) will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Although it does not easily combine with other chemicals, its viscosity at the critical point can be used as a model for a range of fluids. Viscosity originates from the interactions of individual molecules. It is so complicated that, except for the simplest gas, it cannot be calculated accurately from theory. Tests with critical fluids can provide key data, but are limited on Earth because critical fluids are highly compressed by gravity. CVX-2 employs a tiny metal screen vibrating between two electrodes in a bath of critical xenon. The vibrations and how they dampen are used to measure viscosity. CVX flew on STS-85 (1997), where it revealed that, close to the critical point, the xenon is partly elastic: it can 'stretch' as well as flow. For STS-107, the hardware has been enhanced to determine if critical xenon is a shear-thinning fluid.

Berg, Robert F.↗