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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
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Apollo 14 mission: Inability to disconnect main bus A

During entry, the Apollo 14 spacecraft busses should have de-energized when the main bus-tie motor switches were switched to the off position. One motor switch did not transfer and main bus A remained energized until the battery bus-tie circuit breakers were opened after landing. Analysis revealed that residual catalyst caused the terminal pin seals to revert to a gummy state. Resulting reversion products then migrated to the motor commutator and caused brush degradation, increased and erratic commutator resistance, and reduced motor torque. The motor stalled when available motor torque was reduced below that required to drive through the maximum torque point of the switch.

Source record↗
NASA NTRS1972

Development of a space qualified high reliability rotary actuator. Volume 1: Technical report

A space-qualified, high reliability, 150 ft-lb rated torque rotary acutator based on the Bendix Dynavector drive concept was developed. This drive is an integrated variable reluctance orbit motor-epicyclic transmission actuator. The performance goals were based on future control moment gyro torquer applications and represent a significant advancement in the torque-to-weight ratio, backlash, inertia and response characteristics of electric rotary drives. The program accomplishments have been in two areas: (1) the development of two high ratio (818:1) actuator configurations (breadboard and flightweight), and (2) the invention of a reliable proximity switch sensor system for self-commutation without use of optical or electrical brush techniques.

Presley, R. W.↗
NASA NTRS1972

Development of a space qualified high reliability rotary actuator for spaceflight use. Volume 2: Appendices to technical report

A space-qualified, high reliability, 150 ft-lb rated torque rotary actuator is described. This drive is an integrated variable reluctance orbit motor-epicyclic transmission actuator. The performance goals were based on future control moment gyrotorquer applications and represent an advancement in the torque-to-weight ratio, backlash, inertia and response characteristics of electric rotary drives. The program accomplishments have been in two areas (1) the development of two high ratio (818:1) actuator configurations (breadboard and flightweight) and (2) the invention of a reliable proximity switch sensor system for self-commutation without use of optical or electrical brush techniques.

Presley, R. W.↗
NASA NTRS1973

In-orbit performance of the ITOS improved attitude control system with Hall generator brushless motor and earth-splitting technique

The National Aeronautics and Space Administration (NASA), launched ITOS-D with an improved attitude control system. A Hall generator brushless dc torque motor replaced the brush dc torque motor on Tiros-M and ITOS-A. Two CO2 attitude horizon sensors and one mirror replaced the four wideband horizon sensors and two mirrors on ITOS-1 and NOAA-1. Redundant pitch-control electronic boxes containing additional electronic circuitry for earth-splitting and brushless motor electronics were used. A method of generating a spacecraft earth-facing side reference for comparison to the time occurrence of the earth-splitting pulse was used to automatically correct pitch-attitude error. A single rotating flywheel, supported by a single bearing, provided gyroscopic stability and the required momentum interchange to keep one side of the satellite facing the earth. Magnetic torquing against the earth's magnetic field eliminated the requirement for expendable propellants which would limit satellite life in orbit.

Peacock, W. M.↗
NASA NTRS1973

Superflywheel energy storage system

A windpowered system using the superflywheel configuration for energy storage is considered. Basic elements of superflywheels are thin rods assembled in pregrooved hub lamina so that they fan out in radial orientation. Adjacent layers of hub lamina are assembled 90 degree in rotation to each other so as to form a circular brush configuration. Thus stress concentrations and rod failure are minimized and realistic failure containment for a high performance flywheel is obtained.

Rabenhorst, D. W.↗
NASA NTRS1974

Interactive analysis and evaluation of ERTS data for regional planning and urban development: A Los Angeles Basin case study

The progression endemic to the ERTS Data Use Experiment SR 124 in data quality, analysis sophistication and applications responsiveness is reviewed. The roles of the variety of ERTS products, including the supporting underflight aircraft imagery at various scales, are discussed in the context of this investigation. The versatility of interpretation techniques and outputs developed and implemented via the General Electric Multispectral Information Extraction Systems is described and exemplified by both system-expository and applications-explanatory products. The wide-ranging and in-depth applications studied in the course of this experiment can be characterized as community-oriented and agency-directed. In the former, generic category, which is primarily data-contextual, problems analyzed dealt with agricultural systems, surface water bodies, snow cover, brush fire burns, forestry, grass growth, parks - golf courses - cemeteries, dust storms, grading sites, geological features and coastal water structure. The ERTS MSS band selectivity and measurements thresholds were of primary interest here. The agency-directed application areas have been user-evaluational in nature. Beginning with overall urbanized regional analysis of land cover density-development intensity, residential areas were analyzed for ascertaining if housing types could be aggregated with any degree of reliability.

Raje, S.↗
NASA NTRS1974

Reflectance of vegetation, soil, and water

The author has identified the following significant results. The majority of the rangelands of Hidalgo County, Texas are used in cow-calf operations. Continuous year-long grazing is practiced on about 60% of the acreage and some type of deferred system on the rest. Mechanical brush control is used more than chemical control. Ground surveys gave representative estimates for 15 vegetable crops produced in Hidalgo County. ERTS-1 data were used to estimate the acreage of citrus in the county. Combined Kubleka Munk and regression models, that included a term for shadow areas, gave a higher correlation of composite canopy reflectance with ground truth than either model alone.

Wiegand, C. L.↗
NASA NTRS1974

A study of the early detection of insect infestations and density/distribution of host plants

The author has identified the following significant results. Significant results have been obtained in the identification of citrus, sugarcane, winter vegetables, irrigated pastures, and unimproved pastures which contain brush. Land without vegetation, lakes, roads, and waterways can also be determined. Different densities of vegetation covering some cultivated areas are apparent. The practical applications of these results are many. The abundance of host plants of pests can be determined. Avenues of entry of pests can be plotted, facilitating control or preventing entry of pest species. The boundaries of areas to be quarantined can be accurately established after viewing the S-190B data. Better cultural methods can be employed such as planning where to plant certain crops that indirectly are detrimental to those already growing. This would relate to such factors as pesticide drift or alternate hosts of major pests.

Hart, W. G.↗
NASA NTRS1975

Developing processing techniques for Skylab data

The author has identified the following significant results. The effects of misregistration and the scan-line-straightening algorithm on multispectral data were found to be: (1) there is greatly increased misregistration in scan-line-straightening data over conic data; (2) scanner caused misregistration between any pairs of channels may not be corrected for in scan-line-straightened data; and (3) this data will have few pure field center pixels than will conic data. A program SIMSIG was developed implementing the signature simulation model. Data processing stages of the experiment were carried out, and an analysis was made of the effects of spatial misregistration on field center classification accuracy. Fifteen signatures originally used for classifying the data were analyzed, showing the following breakdown: corn (4 signatures), trees (2), brush (1), grasses, weeds, etc. (5), bare soil (1), soybeans (1), and alfalfa (1).

Nalepka, R. F.↗
NASA NTRS1975

A study of the early detection of insect infestations and density/distribution of host plants

The author has identified the following significant results. With comparative observations of film types and seasonal influences on reflectance characteristics, many crop varieties can be identified. This study shows that citrus, sugar cane, brush, some winter vegetables, and grain crops could be identified. Vegetative patterns in border areas can be detected. This information can be useful in detecting avenues of entry of pest species and areas of stress that require vigilance in stopping the spread of destructive species. Influence of some environmental factors on crops that may be confused with pest injury, or related factors, can be detected and identified with Skylab data (S-190B).

Hart, W. G.↗
NASA NTRS1976

Analysis of recreational land using Skylab data

The author has identified the following significant results. S192 data collected on 5 August 1973 were processed by computer to produce a classification map of a part of the Gratiot-Saginaw State Game Area in south central Michigan. A 10-category map was prepared of an area consisting of diverse terrain types, including forests, wetlands, brush, and herbaceous vegetation. An accuracy check indicated that 54% of the pixels were correctly recognized. When these ten scene classes were consolidated to a 5-category map, the accuracy increased to 72%. S190 A, S190 B, and S192 data can be used for regional surveys of existing and potential recreation sites, for delineation of open space, and for preliminary evaluation of geographically extensive sites.

Sattinger, I. J.↗
NASA NTRS1975

Modeling of turbine blade tip contact

A mathematical model is developed to evaluate a number of physical effects in turbomachine blade tip contact on the basis of a broad brush approach to provide insights without undue complexity. The analysis is restricted to the case of a shoe encountering a moving blade row and pressing against it with a fixed time-average force. Relative displacement components in the contact region are identified and determined. Two key equations are derived, where it is shown that wear rate plays a strong role in determining the traversal speed of the contact patch. The formula for estimating the size of the contact patch shows that the higher the traversal speed is, the wider is the contact patch.

Burton, R. A.↗
NASA NTRS1975

Cadmium sulfide solar cells

Development, fabrication and applications of CdS solar cells are reviewed in detail. The suitability of CdS cells for large solar panels and microcircuitry, and their low cost, are emphasized. Developments are reviewed by manufacturer-developer. Vapor phase deposition of thin-film solar cells, doping and co-evaporation, sputtering, chemical spray, and sintered layers are reviewed, in addition to spray deposition, monograin layer structures, and silk screening. Formation of junctions by electroplating, evaporation, brushing, CuCl dip, and chemiplating are discussed, along with counterelectrode fabrication, VPD film structures, the Cu2S barrier layer, and various photovoltaic effects (contact photovoltage, light intensity variation, optical enhancement), and various other CdS topics.

Stanley, A. G.↗
NASA NTRS1978

No-spill touchup paint container

Container has two-piece threaded device that is installed in hole in standard metal lid. In addition to preventing spillage, device provides better brush support and wiper edge.

Peters, R. L.↗
NASA NTRS1978

Space-age vacuum cleaning

Varied concepts for brushes and air handling remove dirt more effectively. Vacuum-cleaning techniques may be used in combination. Many of these concepts, while not appropriate for household cleaning, may find use in industry, research, and medicine.

Schneider, H. W.↗
NASA NTRS1976

Detection and mapping of mineralized areas in the Cortez-Uinta Belt, Utah-Nevada using computer-enhanced ERTS imagery

The author has identified the following significant results. The reflectance spectra of most hydrothermally altered rocks were characterized by broad ferric iron absorption bands short of 1.1 microns and a sharper hydroxyl band near 2.2 microns; maximum reflectance occurred near 1.6 microns. Their features became more prominent as albedo increased. The MSS color ratio composite images were the most effective and practical means for detecting and mapping limonitic rocks in areas having less than about 50 percent desert brush cover and less than 25-35 percent coniferous tree cover. Limonitic altered and unaltered rocks could not be distinguished in MSS color ratio composite images.

Rowan, L. C.↗
NASA NTRS1977

Development of a drive system for a sequential space camera contract modification 4(S)

The brush type dc motor and clutch were eliminated from the design of the 16 mm space sequential camera design and replaced by an electronically commutated motor. The new drive system reduces the current consumption at 24 fps to 220 mA. The drive can be programmed and controlled externally from the multipurpose programmable timer/intervalometer, as well as being controlled locally from the camera.

Sharpsteen, J. T.↗