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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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Structural dynamics research on launch vehicles at Langley Research Center, examining analytical method limitations and need for improved mathematical models for vibrational characteristics
Analytical method for determining axisymmetric longitudinal mode shapes and frequencies of incompressible and inviscid fluid in pressurized flexible oblate spheroidal propellant tank
An analytical method for computing unsteady flow conditions in liquid-filled flow systems is developed. The method which is called the wave plan incorporates distributed parameter and nonlinear effects including the effects of viscous resistance. The wave plan is essentially a solution synthesized from the effects of incremental step pressure pulses. The pressure pulses are generated because of incremental flow-rate changes that originate in a hydraulic system from a variety of sources, including the mechanical motion of the system structure. The pressure pulses propagate throughout the system at sonic velocity and are partially transmitted and reflected at each discontinuity. The velocity change caused by each pressure pulse is obtained from the Joukowski relation. Pressure and velocity time histories at any point in the system are obtained by a timewise summation of the contributions of the incremental pressure pulses passing that point. The analysis is presented in a form general enough to be applied to a variety of hydraulic systems. To illustrate the application of the method to a specific system, the response of a straight hydraulic line to a sinusoidal orifice-area variation of an upstream valve is computed. Both a constant-cross- section line and a tapered line are analyzed in the examples, and various nonlinear effects evaluated. Comparisons are carried out with experimental data obtained for the constant-diameter line and good agreement is shown to exist.
Until recent years the origin of life and its possible occurrence elsewhere in the universe have been matters for speculation only. The rapid growth of molecular biology since 1940 has, to be sure, made it possible to discuss life's origins in far more precise and explicit terms than was possible earlier; and the subject entered a new experimental phase in the 1950's with successful abiogenic synthesis of important biochemical substances in conditions simulating the presumptive environment of the primitive Earth. But the real transformation that the subject has undergone stems from the spectacular growth of space technology in the last decade. The possibility of life's origin and occurrence on planets other than ours is no longer limited to idle speculation: it has entered the realm of the testable, of science in the strict sense. Given the rockets now available, and especially those available by 1969, it has become fully realistic to consider plans for the biological exploration of Mars. The study that this report seeks to interpret was initiated in June, 1964, by the Space Science Board of the National Academy of Sciences to examine this possibility. The working group comprised 36 people representing a broad spectrum of scientific interests: evolutionary biology, genetics, microbiology, biochemistry and molecular biology, animal physiology, soil chemistry, organic chemistry, planetary astronomy, geochemistry, and theoretical physics. The participants included some with considerable prior involvement in problems of space exploration and others with none. Advice was also sought outside the group of immediate participants on the potentialities of selected analytical methods for the experimental study of extraterrestrial life and its environment. More than 30 individuals contributed in this fashion written assessments of techniques in which they were particularly well versed. Our task was to examine the scientific foundations and merits of the proposal to undertake a biological exploration of Mars. What are the potential scientific yields? How valuable, if attained, would they be? What, in fact, is the possibility of life occurring on Mars? And of our detecting it with available and foreseeable technology? What could be achieved by further astronomical work from Earth? by Martian fly-by missions? by Martian orbiters? and Martian Landers? What payloads would we recommend for planetary missions? What timing and over-all strategy would we recommend for Martian exploration were we to consider it worthwhile at all? In brief, the over-all purpose was to recommend to. the government, through the Academy's Space Science Board, whether or not a biological exploration of Mars should be included in the nation's space program over the next few decades; and, further, to outline what that program, if any, should be.
Analytic method for determining elastic constants of three-dimensional reinforcing filaments for plastics
Structural dynamics research on launch vehicles at Langley Research Center, examining analytical method limitations and need for improved mathematical models for vibrational characteristics
Nonlinear equation relates the flowrate at an orifice to that at a station downstream from the orifice. This equation should aid in understanding combustion instabilities and should not be subject to the substantial errors of prior analytical methods.
Analytical method using series expansion to determine effect of nonlinearities on output of coherent optical correlator
Analytical methods defining location of reference horizons in earth horizon radiance profile
Analytical methods for determination of trajectories, loads, and heating experienced by spacecraft passing through rocket exhaust field
Axisymmetric blunt bodies shock standoff distances in hypersonic flow determined by numerical and analytic methods
Computer program is used for analysis and design of gas turbine combustors. The program analyzes fluid flow, combustion, and heat transfer in annular and rectangular combustors with diffusers, making use of currently available analytical methods and correlations.
Analytical methods user instructions, data preparation guide, and sample problem for generalized heat transfer computer routine
Analytical methods of predicting electron density in rocket exhaust plumes based on detailed descriptions of flow regimes and chemical models
Vibrational characteristics of thin shells - review of analytical methods, fabrication methods, and publications
Analytical methods for dynamic stability analyses of large launch vehicles during flight through and exit from earth atmosphere
Analytical methods to determine capability of space vehicle guidance system, and Liapunov functions for stability of nonlinear systems
Analytical method for finding heat balance of insulated OGO experiment packages from thermal stability data and without solar simulation