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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 325 records · Page 18

Organic contamination analysis: High resolution mass spectrometric analysis of surface organics on selected areas of Surveyor 3

The mirror and middle shroud were extracted for organics by washing the surfaces with solvents. The techniques are discussed. Ion microprobe analyses of the primarily atomic species are presented. The sources of the organic contaminants are: (1) hydrocarbons from lubricating oils and general terrestrial contamination, (2) dioctyl phthalate, probably from polyethylene bagging material (the plasticizer), (3) carboxylic acids from decomposition of grease and general terrestrial contamination, (4) silicones from sources such as lubricating oil, (5) outgassing of electronics and plasticizer, (6) vinyl alcohol and styrene copolymer, probably from electronic insulation, and (7) nitrogenous compounds from the lunar module and possibly Surveyor 3 engine exhaust.

Simoneit, B. R.↗

Finite element analysis of elasto-plastic soils. Report no. 4: Finite element analysis of elasto-plastic frictional materials for application to lunar earth sciences

The behavior of finite element models employing different constitutive relations to describe the stress-strain behavior of soils is investigated. Three models, which assume small strain theory is applicable, include a nondilatant, a dilatant and a strain hardening constitutive relation. Two models are formulated using large strain theory and include a hyperbolic and a Tresca elastic perfectly plastic constitutive relation. These finite element models are used to analyze retaining walls and footings. Methods of improving the finite element solutions are investigated. For nonlinear problems better solutions can be obtained by using smaller load increment sizes and more iterations per load increment than by increasing the number of elements. Suitable methods of treating tension stresses and stresses which exceed the yield criteria are discussed.

Marr, W. A., Jr.↗

Modification and updating of the Manned Activity Scheduling System (MASS) for shuttle and shuttle payloads analysis. Volume 2: Space shuttle sortie payload analysis

Space shuttle operations include a significant number of launches with a sortie laboratory serving as a facility for manned experimentation in space. Planning a program of space experiments for a facility of this type requires that both the composition of the laboratory payload and the schedule of experiment operations for each payload be carefully selected. Experiment operations are investigated using the manned activity scheduling system (MASS). Schedules provided by these models assist in selecting experiment groups that efficiently use the laboratory resources and yield the desired experiment accomplishment at the program level. An alternate use of the MASS models provides for establishing the time-dependent supporting resources required for a specified candidate payload. A procedure for defining and analyzing shuttle sortie payloads was developed. This procedure was then applied to the definition of mixed-discipline experiment payloads for an advanced technology laboratory (ATL) supported by two-and three-man crews. The ATL payloads, including schedules of experiment operations, were defined to realize a high percentage of experiment accomplishment. The study considers the sensitivity of experiment accomplishment rate to variations of system parameters such as crew cross training, crew operations, shuttle and laboratory resources, ground target systems, and operational orbits.

Huyett, R. C.↗

Analysis and design of three dimensional supersonic nozzles. Volume 1: Nozzle-exhaust flow field analysis by a reference plane characteristics technique

A second order numerical method employing reference plane characteristics has been developed for the calculation of geometrically complex three dimensional nozzle-exhaust flow fields, heretofore uncalculable by existing methods. The nozzles may have irregular cross sections with swept throats and may be stacked in modules using the vehicle undersurface for additional expansion. The nozzles may have highly nonuniform entrance conditions, the medium considered being an equilibrium hydrogen-air mixture. The program calculates and carries along the underexpansion shock and contact as discrete discontinuity surfaces, for a nonuniform vehicle external flow.

Dash, S.↗

Analysis and design of three dimensional supersonic nozzles. Volume 2: Numerical program for analysis of nozzle-exhaust flow fields

The FORTRAN IV Program developed to analyze the flow field associated with scramjet exhaust systems is presented. The instructions for preparing input and interpreting output are described. The program analyzes steady three dimensional supersonic flow by the reference plane characteristic technique. The governing equations and numerical techniques employed are presented in Volume 1 of this report.

Kalben, P.↗

Operations analysis, study 2.6. Volume 2: Analysis results

Results are presented of the assessment of the space transportation system as it applies to future space program planning. Comparisons are given between space servicing and ground refurbishment of payloads. Mission characterization, logistic vehicle options, and payload design options are also discussed.

Wolfe, R. R.↗

Frequency modulation television analysis: Distortion analysis

Computer simulation is used to calculate the time-domain waveform of standard T-pulse-and-bar test signal distorted in passing through an FM television system. The simulator includes flat or preemphasized systems and requires specification of the RF predetection filter characteristics. The predetection filters are modeled with frequency-symmetric Chebyshev (0.1-db ripple) and Butterworth filters. The computer was used to calculate distorted output signals for sixty-four different specified systems, and the output waveforms are plotted for all sixty-four. Comparison of the plotted graphs indicates that a Chebyshev predetection filter of four poles causes slightly more signal distortion than a corresponding Butterworth filter and the signal distortion increases as the number of poles increases. An increase in the peak deviation also increases signal distortion. Distortion also increases with the addition of preemphasis.

Hodge, W. H.↗

Sensitivity analysis of torsional vibration characteristics of helicopter rotor blades. Part 1: Structural dynamics analysis

A theoretical investigation of structural vibration characteristics of rotor blades was carried out. Coupled equations of motion for flapwise bending and torsion were formulated for rotor blades with noncollinear elastic and mass axes. The finite element method was applied for a detailed representation of blade structural properties. Coupled structural mass and stiffness coefficients were evaluated. The range of validity of a set of coupled equations of motion linearized with respect to eccentricity between elastic and mass axes was investigated. The sensitivity of blade vibration characteristics to torsion were evaluated by varying blade geometric properties, boundary conditions, and eccentricities between mass and elastic axes.

Bratanow, T.↗

Space shuttle/food system study. Volume 2, Appendix G: Ground support system analysis. Appendix H: Galley functional details analysis

The capabilities for preflight feeding of flight personnel and the supply and control of the space shuttle flight food system were investigated to determine ground support requirements; and the functional details of an onboard food system galley are shown in photographic mockups. The elements which were identified as necessary to the efficient accomplishment of ground support functions include the following: (1) administration; (2) dietetics; (3) analytical laboratories; (4) flight food warehouse; (5) stowage module assembly area; (6) launch site module storage area; (7) alert crew restaurant and disperse crew galleys; (8) ground food warehouse; (9) manufacturing facilities; (10) transport; and (11) computer support. Each element is discussed according to the design criteria of minimum cost, maximum flexibility, reliability, and efficiency consistent with space shuttle requirements. The galley mockup overview illustrates the initial operation configuration, food stowage locations, meal assembly and serving trays, meal preparation configuration, serving, trash management, and the logistics of handling and cleanup equipment.

Source record↗

Apollo data analysis experiment S-211. Low brightness image data analysis

The scientific analyses of photographic data in astronomy obtained by the Apollo Orbital Science Photographic Team during Apollo flights 14 through 17 are described. Some of the tasks are the collection and correlation of Quick-Look listings, working prints for further study, the generation of post-mission reports, and project reports. Postflight calibrations of the flight photographic systems are carried out, and lens vignetting effects are corrected. The data handling is described and includes photodigitization of photographic scenes, calibrated step-wedges, and vignetting patterns, which are followed by computer program processing of the film density readings.

Mercer, R. D.↗

Payload design requirements analysis (study 2.2). Volume 3. Guideline analysis

Payloads to be launched on the space shuttle/space tug/sortie lab combinations are discussed. The payloads are of four types: (1) expendable, (2) ground refurbishable, (3) on-orbit maintainable, and (4) sortie. Economic comparisons are limited to the four types of payloads described. Additional system guidelines were developed by analyzing two payloads parameterically and demonstrating the results on an example satellite. In addition to analyzing the selected guidelines, emphasis was placed on providing economic tradeoff data and identifying payload parameters influencing the low cost approaches.

Shiokari, T.↗

A failsafe analysis using NASTRAN's piecewise linear analysis and a nine node linear crack element

A two-dimensional crack element was implemented into NASTRAN as a user dummy element and used to study failsafe characteristics of the C5A fuselage. The element is formulated from Reitsner's functional requiring that it satisfy compatability with the linear boundary displacement elements in NASTRAN. Its accuracy is demonstrated by analyzing for the stress intensity factors of two simple crack configurations for which there are classic solutions.

Wilkinson, R. F.↗

Standardization and program effect analysis (Study 2.4). Volume 2: Equipment commonality analysis

The feasibility and cost savings of using flight-proven components in designing spacecraft were investigated. The components analyzed were (1) large space telescope, (2) stratospheric aerosol and gas equipment, (3) mapping mission, (4) solar maximum mission, and (5) Tiros-N. It is concluded that flight-proven hardware can be used with not-too-extensive modification, and significant savings can be realized. The cost savings for each component are presented.

Shiokari, T.↗