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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Spacecraft systems design trade-offs for the Earth Resources Technology Satellite.

The Earth Resources Technology Satellite Program's use of flight proven hardware in the design of a satellite for earth sensor payload support and data handling is discussed. The use of an existing satellite as the building block around which additional support systems such as the orbit adjust system, the redundant wideband telemetry systems, the second regulated power system, and the quad redundant command system is analyzed. System performance seen in orbit vs design objectives are discussed to point up the success of the design approach chosen. Also discussed are the schedule and cost benefits derived from the use of previously developed hardware with additional subsystems as required to meet program requirements.

Branchflower, G. A.↗
NASA NTRS1975

Analysis and Preliminary Design of an Advanced Technology Transport Flight Control System

The analysis and preliminary design of an advanced technology transport aircraft flight control system using avionics and flight control concepts appropriate to the 1980-1985 time period are discussed. Specifically, the techniques and requirements of the flight control system were established, a number of candidate configurations were defined, and an evaluation of these configurations was performed to establish a recommended approach. Candidate configurations based on redundant integration of various sensor types, computational methods, servo actuator arrangements and data-transfer techniques were defined to the functional module and piece-part level. Life-cycle costs, for the flight control configurations, as determined in an operational environment model for 200 aircraft over a 15-year service life, were the basis of the optimum configuration selection tradeoff. The recommended system concept is a quad digital computer configuration utilizing a small microprocessor for input/output control, a hexad skewed set of conventional sensors for body rate and body acceleration, and triple integrated actuators.

Frazzini, R.↗
NASA NTRS1977

Multifrequency, broadband, dual-polarized antenna

Corrugated, conical horn, ring-loaded antenna can be fed through vertex of cone with wideband waveguides, such as double-ridged rectangular or quad-ridged circular, or simply ring-loaded, corrugated waveguides. Antenna is also fed through coupling apertures in side of cone at appropriate diameters.

Green, K. A.↗
NASA NTRS1975

Ohio's statewide land use inventory: An operational approach for applying LANDSAT data to state, regional and local planning programs

The programmatic, technical, user application, and cost factors associated with the development of an operational, statewide land use inventory from LANDSAT data are described. The LANDSAT multispectral data are subjected to geometrical and categorical processing to produce map files for each of the 200 fifteen (15) minute quads covering Ohio. Computer compatible tapes are rescanned to produce inventory tapes which identify eight (8) Level I land use categories and a variety of Level II categories. The inventory tapes are processed through a series of ten (10) software programs developed by the State of Ohio. The net result is a computerized inventory which can be displayed in map or tabular form for various geographic units, at a variety of scales and for selected categories of usage. The computerized inventory data files are applied to technical programs developed by the various state agencies to be used in state, regional, and local planning programs.

Baldridge, P. E.↗
NASA NTRS1975

National energy conservation

A set of energy conservation actions that cut across all sectors of the economy were analyzed so that all actions under consideration be analyzed systematically and as a whole. The actions considered were as follows: (1) roll back the price of newly discovered oil, (2) freeze gasoline production for 3 years at 1972 levels, (3) mandate automobile mileage improvements, (4) require industry to improve energy efficiency, (5) require manufacture of household appliances with greater efficiency, (6) force conversion of many power plants from gas and oil to coal. The results showed that considerable gas and oil would be saved by forcing switches to coal. However, the large scale switch to coal was shown to require greatly increased outputs from many other industries that in turn require more energy. It was estimated that nearly 2.5 quads of additional coal were needed to produce these additional requirements. Also, the indirect requirements would create more jobs.

Source record↗
NASA NTRS1975

Shuttle orbiter C-band beacon antenna location study

A recommendation for the location of the Space Shuttle C-Band Beacon Antenna(s) to be used during Approach and Landing Tests was made. The study has included an Orbiter-to-ground radar look angle evaluation, a vehicle shadowing evaluation and extensive 1/10-scale antenna pattern measurements. Locations were limited to the cutouts for the S-Band Quads and Hemis to minimize skin perturbation. The results show that a single C-Band Antenna located in the lower Hemi cutout will provide optimum coverage and eliminate the need for switching and the undesirable interferometer effects of two antennas.

Lindsey, J. F.↗
NASA NTRS1977

Simple constant-current-regulated power supply

Supply incorporates soft-start circuit that slowly ramps current up to set point at turn-on. Supply consists of full-wave rectifier, regulating pass transistor, current feedback circuit, and quad single-supply operational-amplifier circuit providing control. Technique is applicable to any system requiring constant dc current, such as vacuum tube equipment, heaters, or battery charges; it has been used to supply constant current for instrument calibration.

Priebe, D. H. E.↗
NASA NTRS1978

Model for redundant-sensor signal errors

Report describes application of order statistics to analysis of failure modes in redundant systems. Report provides detailed mathematical discussion of approach, accompanied by graphs and equations. Techniques are relevant to process that demand high reliability, such as manufacture of dangerous chemicals. It also includes discussion of quad-redundant system.

Sowada, D. J.↗
NASA NTRS1978

Agricultural and industrial process heat

The application of solar energy to agricultural and industrial process heat requirements is discussed. This energy end use sector has been the largest and it appears that solar energy can, when fully developed and commercialized, displace from three to eight or more quads of oil and natural gas in U.S. industry. This potential for fossil fuel displacement in the agricultural and industrial process heat area sector represents a possible savings of 1.4 to 3.8 million barrels of oil daily.

Dollard, J.↗
NASA NTRS1979

Gimbal bearing design considerations and friction control

The design considerations of bearing selection, bearing fits, bearing installation, and thermal control are discussed for a gimbal with a high stiffness, low friction torque requirement. Tradeoffs between a quad set of small diameter spread apart or a large diameter bearing pair resulted in a cleaner, lighter, stiffer unit with the latter selection. Bearing fits were designed to eliminate clearances with tolerances of .00127 mm 00005 in) on the bearing shafts and housings. The problems in metrology are discussed and a perferred technique for measurement of small cross-section bearings described. A technique for installation to assure proper seating of the bearing is offered. Where transient thermal conditions are involved, a method of controlling bearing friction by active control of bearing temperature gradients including the use of bearing unload test curves is described.

Kramer, N. R.↗
NASA NTRS1980

Testing of reciprocating seals for application in a Stirling cycle engine

Six single stage reciprocating seal configurations to the requirements of the Stirling cycle engine were evaluated. The seals tested were: the Boeing Footseal, NASA Chevron polyimide seal, Bell seal, Quad seal, Tetraseal, and Dynabak seal. None of these seal configurations met the leakage goals of .002 cc/sec at helium gas pressure of 1.22 x 10 to the 7th power PA, rod speed of 7.19 m/sec peak, and seal environmental temperature of 408 K for 1500 hours. Most seals failed due to high temperatures. Catastrophic failures were observed for a minimum number of test runs characterized by extremely high leakage rates and large temperature rises. The Bell seal attained 63 hours of run time at significantly lowered test conditions.

Curulla, J. F.↗
NASA NTRS1980

Large wind turbines: A utility option for the generation of electricity

The wind resource is such that wind energy generation has the potential to save 6-7 quads of energy nationally. Thus, the Federal Government is sponsoring and encouraging the development of cost effective and reliable wind turbines. One element of the Federal Wind Energy Programs, Large Horizontal Axis Wind Turbine Development, is managed by the NASA Lewis Research Center for the Department of Energy. There are several ongoing wind system development projects oriented primarily toward utility application within this program element. In addition, a comprehensive technology program supporting the wind turbine development projects is being conducted. An overview is presented of the NASA activities with emphasis on application of large wind turbines for generation of electricity by utility systems.

Robbins, W. H.↗
NASA NTRS1982

New Algorithms Manage Fourfold Redundancy

Redundant sensors, actuators, and computers improve reliability of complex control systems, such as those in nuclear powerplants and aircraft. If one or more redundant elements fail, another takes over so that normal operation is not interrupted. Quad selection filter rejects data from null-failed and hardover-failed and hardover-failed units.

Gelderloos, H. C.↗
NASA NTRS1981

Hoop/column antenna technology development summary

The Langley Research program for development of hoop/column antenna technology was redirected and includes the fabrication and test of models such as the 4 gore segment of a 50 meter antenna and the 15 meter diameter fully deployable antenna. Significant results were obtained in the point design that includes a quad aperture reflector system for multiple beam applications.

Campbell, T. G.↗
NASA NTRS1981

Radio frequency performance predictions for the hoop/column point design

Preliminary antenna pattern tests were conducted to determine if catastrophic effects were produced by cables (conducting) in the aperture. This test consisted of an apex feed illuminating a 3 meter solid reflector. A hoop/column configuration was used in positioning the various wires and cables. Radiation patterns were measured at 7 GHz and 10 GHz. No catastrophic effects were observed for this configuration, but additional tests are required to determine the effects for more precision multiple beam applications. In order to better understand the scattering and blockage effects on multiple beam performance, a 35 GHz model was used to model somewhat a single quad aperture configuration. Experimental results using this models are presented in graphs.

Campbell, T. G.↗
NASA NTRS1981

Offset fed utilization of four quadrants of an axially symmetrical antenna structure

Theoretical calculations conducted for the use of the hoop column structure were in a quad antenna configuration. The coverage of the US 48 states by a C band Comsat system, which operates in the 3.7 - 4.2 GHz downlink and 5.925 - 6.425 GHz uplink frequency band is considered. This system provides most of its coverage toward major cities (10 or 18 spot beams) and the rest of its coverage on a contiguous basis for the remaining of the country. An alpha = .5 and .3 cell size (approximate component bandwidth) is assumed. Among the practically infinite possible beam topologies one plan for the area coverage and three plans for the spot beam coverage are analyzed.

Foldes, P.↗
NASA NTRS1982

Inexpensive Logic-Level Converter

Relatively-simple transformer circuit boosts 0-to-5 volt pulses from TTL circuitry to plus or minus 10-volt pulses for transmission over data bus. Also reduces bus voltages to lower voltages required by TTL circuitry. Circuit consists of transformer, two voltage-reference networks, quad differential line receiver, and line driver.

Wilcox, S. W.↗