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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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Analytic procedure evaluates cost of combining absorption-cycle chiller with solar-energy system in residential or commercial application. Procedure assumes that solar-energy system already exists to heat building and that cooling system must be added. Decision is whether to cool building with conventional vapor-compression-cycle chiller or to use solar-energy system to provide heat input to absorption chiller.
Due to the thermal expansion coefficient mismatch (CTE) between the fiber and the matrix, high residual sresses exist in metal matrix composite systems upon cool down from processing temperature to room temperature. An interface material can be placed between the fiber and the matrix to reduce the high tensile residual stresses in the matrix. A computer program was written to minimize the residual stress in the matrix subject to the interface material properties. The decision variables are the interface modulus, thickness and thermal expansion coefficient. The properties of the interface material are optimized such that the average distortion energy in the matrix and the interface is minimized. As a result, the only active variable is the thermal expansion coefficient. The optimum modulus of the interface is always the minimum allowable value and the interface thickness is always the maximum allowable value, independent of the fiber/matrix system. The optimum interface thermal expansion coefficient is always between the values of the fiber and the matrix. Using this analysis, a survey of materials was conducted for use as fiber coatings in some specific composite systems.
The Next Generation Space Telescope (NGST) mission is scheduled to launch in 2007 and be stationed at L2 for a mission life of ten years. The large aperture mirror and optical detectors aboard NGST require shielding from the constant solar energy seen at this orbit. The government reference NGST design, called the Yardstick, baselined a sunshield using an inflation deployment system. During the formulation phase, NGST is spending approximately 25% of the overall budget to foster the development of new technology. The goal is to develop and demonstrate enabling or enhancing technology and provide innovative solutions for the design of the NGST observatory. Inflatable technology falls in the category of enhancing technology due to its advantages in weight, stowed volume and cost. The Inflatable Sunshield in Space (ISIS) flight experiment will provide a realistic space flight demonstration of an inflatable sunshield. The supporting technology development program will provide an information base for the design, manufacture, assembly and testing of large thin membranes and inflatable structural elements for space structures. The ISIS experiment will demonstrate the feasibility of using inflatable technology to passively cool optical systems for NGST and provide correlation between analytical predictions and on orbit results. The experiment will be performed on a Hitchhiker/Space Shuttle mission in late 2001. The ISIS mission is an effort to address several major technical challenges of the NGST inflatable sunshield, namely controlled inflation deployment, plenarity and separation of large stretched membranes, space rigidization of inflatable booms, and dynamic modeling and simulation. This paper will describe the design of the flight experiment and the testing to be performed on-orbit.
Testing of X band high power components in a traveling wave resonator indicates that this improved cooling design reduces temperature in the waveguide and flange. The waveguide power handling capability and power transmission reliability is increased substantially.
Regenerative and radiation cooling, transpiration or film cooling, ablation and inert or endothermic heat sink, used in selecting optimum spacecraft engine thrust chamber cooling techniques
Cold gas cooled lead selenide array for detection of reflected light waves
Heat transfer mechanism for cooling human body in spacecraft cabins and extravehicular pressurized suits
Wall temperature and heat transfer patterns in liquid-propellant rocket thrust chamber coolant channels
Cryogenic propellant boiloff losses in long duration space storage elimination by mechanical reliquefier, considering lunar, Earth-orbit and deep space application for hydrogen and oxygen
Thin insulating Teflon film bonding to internal surface of space cryopanels for increased heat transfer and faster cooling
Materials and cooling of aircraft gas turbine engines, noting nickel and tantalum alloys, turbine-inlet temperatures, coatings, etc
Large ultrahigh-vacuum environmental chamber with liquid-helium-cooled liner for space simulation
Pulse tube and cryomatic gas balancing cryogenic refrigeration methods
Construction and testing of two-stage radiant cooler for day and night high resolution infrared radiometer
Vent subsystem design specifications for use in fuel cell assembly
Recirculating gas cooled test loop facility for Plum Brook reactor
Heat shield efficiency over plane surface during injection through two tangential slots studied in wind tunnel
Thermodynamic flow analysis of feasibility of coolant gas addition to nozzle flow for improved particle formation efficiency in mixed flow colloid thrustor