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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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Vibrational transfer functions for complex structures
Evaluation of effects of vibrational multiple frequency forcing functions is discussed. Computer program for developing vibrational transfer functions is described. Possible applications of computer program are enumerated.
A note on the possible importance of the Gum nebula
Reasons for considering the Gum nebula a fossil H II region are presented. Arguments for different types of fossil regions are given. Possible research projects are enumerated.
Applications analysis of high energy lasers
An analysis and comparison of laser technology with competing technologies were made to determine possible laser applications. The analysis was undertaken as follows: (1) possible applications were listed and categorized; (2) required components were enumerated and the characteristics of these components were extrapolated; (3) complete system characteristics were calculated parametrically for selected applications using the postulated component characteristics; and (4) where possible and appropriate, comparisons were made with competing systems. It was found that any large scale replacement of existing systems and methods by lasers requires many technological advances in laser and associated systems. However, several applications appear feasible, such as low orbit drag make-up, orbit changing, communications, and illumination applications.
Interdisciplinary barriers: An impediment to the effective application of systems engineering
Interdisciplinary transfer of information and technology does not occur very readily, even for system planners, because of the existence of some very real barriers. These barriers to flow of information and technology between disciplines represent one of the important difficulties associated with the application of systems analysis to many problems. The nature and characteristics of some of these barriers are enumerated and discussed in detail. A number of methodologies and techniques which have been specifically developed to aid in the transfer of technology and information across these interdisciplinary barriers is examined.
Distribution of mica polytypes among space groups.
All the possible space groups for mica polytypes are deduced by making use of the characteristics of the mica unit layer and stacking mode. The algebraic properties of the vector-stacking symbol of Ross et al. (1966) are examined, and a simple algorithm for deducing the space group from this symbol is presented. A method considered for enumerating all possible stacking sequences of mica polytypes makes use of a computer.
Computer generation of symbolic network functions - A new theory and implementation.
A new method is presented for obtaining network functions in which some, none, or all of the network elements are represented by symbolic parameters (i.e., symbolic network functions). Unlike the topological tree enumeration or signal flow graph methods generally used to derive symbolic network functions, the proposed procedure employs fast, efficient, numerical-type algorithms to determine the contribution of those network branches that are not represented by symbolic parameters. A computer program called NAPPE (for Network Analysis Program using Parameter Extractions) and incorporating all of the concepts discussed has been written. Several examples illustrating the usefulness and efficiency of NAPPE are presented.
Testing relativistic gravity theories using radio tracking data from planetary orbiting spacecraft.
We present a thorough analysis of a computational method for determining the numerical values of the relativity and other related dynamical parameters using two-way Doppler and ranging data from planetary orbiting spacecraft. The computational method consists of two parts. From Doppler data we first determine the earth-planet components of the position of the orbiting spacecraft relative to the center of gravity of the planet to high accuracy; adding the observed spacecraft range yields a range value to the center of the planet. These constructed earth-planet range data, referred to as normal points, are then treated as raw data in a regression analysis combined with planetary radar delay and meridian circle measurements to solve for the significant solar system dynamical parameters. The major errors sources in the planetary orbiter process are enumerated and their individual effects on the overall accuracy of the normal point accuracies are presented. The accuracies of the parameter estimates as a function of time, data sampling, and a priori assumptions are illustrated.
Detecting and measuring metabolic byproducts by electrochemical sensing
Method of detecting certain groups of bacteria is based on sensing buildup in molecular hydrogen. Apparatus is easy to assemble and use, and it has added advantage that hydrogen evolution by test micro-organisms can be measured automatically and accurately. System has been used to detect and enumerate variety of gram-negative bacteria of enterobacteriaceae group.
The FRALIT teledetection program, using the ERTS-A satellite, for the oceanic littoral of France
There are no author-identified significant results in this report. The French Atlantic Littoral program, utilizing data from the ERTS-1 satellite, is considered. It involves teledetection of the French shoreline along the Atlantic Ocean and English Channel. A description is given of the ERTS-1 orbit and the satellite itself, including the attitude control system, and the data acquisition and transmission equipment. The geographic extent of the area covered by the program is delineated and the subjects studied are enumerated. These include the geomorphology, pedology, hydrology, and vegetation of the maritime marshes; sedimentology, morphology, and hydrology of the intertidal zones; and transport of material in suspension to the mouths of the Seine, the Loire, and the Gironde as a part of the coastal waters study.
Isotope Brayton space power systems and their technology
The objectives of the NASA Brayton Space Power Program and the advantages of achieving an isotope Brayton space power system are enumerated. The paper describes the 2-15 kWe Brayton engine, its subsystems, and major components and summarizes the status of the test program. Two areas of Brayton constituent technology are discussed-gas bearings and heat exchangers. A summary is given of a 500-2500 W isotope Brayton space power system study that showed very attractive performance, simplicity, and low cost for a system in this power range.
Human control capabilities
The capabilities and limitations of man as an element in a closed loop control system under normal environmental conditions are described. Controller characteristics are enumerated, using manual control, quasilinear models, pilot opinion and ratings, compensatory tracking, optimum control models, motion cues, multiple input tracking, multiple loop tracking, transmission delays, and adaptive manual control. Various controls, manipulators, and displays are also considered.
Isotope Brayton space power systems and their technology.
The objectives of the NASA-Lewis Research Center Brayton Space Power Program and the advantages of achieving an isotope Brayton space power system are enumerated. The paper describes the 2-15 kWe Brayton engine, its subsystems, and major components, and summarizes the status of the test program. Two areas of Brayton constituent technology are discussed - gas bearings and heat exchangers. A summary is given of a 500-2500 W isotope Brayton space power system study that showed very attractive performance, simplicity, and low cost for a system in this power range.
Design guidelines for use of adhesives in hybrid microcircuits
Although it is generally accepted that the use of adhesives in the assembly of hybrid microcircuits offers advantages over other bonding methods, there currently does not exist a set of guidelines for the selection of adhesives which will insure that hybrid microcircuits assembled with them will meet the long use-life, high-reliability requirements of electronic equipment for space applications. This study was directed to the identification of the properties of electrically insulative adhesives that potentially could cause problems in such an application, and to the development of evaluation tests to quantify these properties and thus form the basis for establishing suitable guidelines and, ultimately, specifications. Bond strength, outgassing after cure, and corrosivity were selected for detailed attention since they are considered to be especially critical. Introductory discussion includes enumeration and brief comments on the properties of adhesives considered to be important for the proposed application, a general review of polymeric types of adhesives, and identification of the major types of adhesives commercially available and specifically designed for microelectronic use. The specific tests developed to evaluate bond strength, outgassing after cure, and corrosivity are discussed in detail, and comparative results obtained for selected adhesives representative of the major types are given.
A survey of AFFDL parameter estimation efforts and future plans
An overview is presented of the applications of parameter estimation methods to the following areas of interest at the Air Force Flight Dynamics Laboratory (AFFDL): (1) conventional stability and control parameter estimation of rigid aircraft; (2) extension to elastic aircraft; (3) extension to stall/spin aerodynamics of rigid aircraft with a nonlinear model; (4) application to the pilot model identification; and (5) correlation of wind tunnel, drop model and flight test data. Only well-documented algorithms are used with modification to the model as required for the specific application. The genesis of each problem and other background information are discussed which enumerate the algorithms and explain how this information is used to improve existing operational aircraft characteristics as well as specify design criteria for future USAF aerospace vehicles.
Estimate of winter wheat yield from ERTS-1
A model for estimating wheat yield per acre has been applied to acreage estimates derived from ERTS-1 imagery to project the 1973 wheat yields for a ten county area in southwest Kansas. The results (41.04 million bushels) are within 3 per cent of the preharvest estimates for the same area prepared by the USDA Statistical Reporting Service (39.91 million bushels). The projection from ERTS data is based on a visual enumeration of all detectable wheat fields in the study area and was completed while the harvest was in progress. Visual identification of winter wheat is readily achieved by using a temporal sequence of images (band 5 for Sept.-Oct.; band 5 for Dec.-Jan.; and band 5 and 7 for March-April). Identification can be improved by stratifying the project area into subregions having more or less homogeneous agricultural practices and crop mixes. By doing this, small changes in the spectral appearance of wheat related to soil type, irrigation, etc. can be accounted for. The interpretation rules developed by visual analysis can be automated for rapid computer surveys.
Crop identification and acreage measurement utilizing ERTS imagery
The Statistical Reporting Service of the U.S. Department of Agriculture is evaluating ERTS-1 imagery as a potential tool for estimating crop acreage. A main data source for the estimates is obtained by enumerating small land parcels that have been randomly selected from the total U.S. land area. These small parcels are being used as ground observations in this investigation. The test sites are located in Missouri, Kansas, Idaho, and South Dakota. The major crops of interest are wheat, cotton, corn, soybeans, sugar beets, potatoes, oats, alfalfa, and grain sorghum. Some of the crops are unique to a given site while others are common in two or three states. This provides an opportunity to observe crops grown under different conditions. Results for the Missouri test site are presented. Results of temporal overlays, unequal prior probabilities, and sample classifiers are discussed. The amount of improvement that each technique contributes is shown in terms of overall performance. The results show that useful information for making crop acreage estimates can be obtained from ERTS-1 data.
Cometary investigation during the total solar eclipse of 7 March 1970
Photographic observations made during the solar eclipses of 1963, 1966, 1968, and 1970 indicate the presence of previously unidentified celestial objects in the near-angular vicinity of the sun. Observational data and equipment are described. Possible origins of the objects are enumerated, as well as suggested future experiments to confirm the results.