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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
All sourcesNASA NTRSDOE OSTI
NASA NTRS1965

A rising tide of structural problems.

Structural problems for advanced launch vehicle and spacecraft, discussing size, environment, material, human attitude, propellant tank, bulkhead and lunar-vehicle landing-gear designs

PROPELLANT TANK↗
NASA NTRS1973

Tides in the upper atmosphere: A controversy resolved?

Diurnal temperature variations in the upper atmosphere are caused by heating resulting from the absorption of solar energy by ozone near the stratopause and by water vapor in the troposphere. Theoretical temperature variations given as a function of time and height show a discrepancy for the maximum temperature variation. A comprehensive set of acoustic grande soundings establish phase changes with altitude in agreement with the theory although times of maximum and minimum are not aligned at all altitudes.

Theon, J. S.↗
NASA NTRS1974

Moonquake predetermination and tides

A pattern in moonquakes, which correlates with the monthly tidal cycle, also correlates with a phase-shifted pattern of a 7-month tidal cycle. The lead of approximately 2 months in moonquake occurrence can be explained if local tidal forces are combined with a moonquake-driving force. This force, assumed to result from the 6-yr physical libration in latitude, would cause N-S sliding of an outer layer across a solid layer within a decoupled core in a lunar model. During 1969-1971, the sliding would be southward with a progression of monthly maxima in the combined forces. Where these forces control moonquakes, the reversal in direction of the 6-year cyclic force in early 1972 should cause a minimum in moonquake activity. Decreases toward such a minimum did occur simultaneously in the similar progressions of monthly moonquakes and maxima in the combined forces at the most active hypocenter. Repetition of the 1966-1971 force pattern in 1975-1977 should produce a corresponding repetition of the moonquake pattern.

Chapman, W. B.↗
NASA NTRS1974

Tides in the giant planets

Goldreich and Soter's (1966) discussion of tidal dissipation in the Jovian planets is reexamined for planetary models which possess an appreciable internal heat source. The tidal torque produced in a fully liquid planet is calculated as a function of the average viscosity in the interior. Turbulent viscosity, which is produced by the convection of internal heat to the surface, seems to be capable of producing small (about a few per cent) changes in the orbits of the innermost satellites of Jupiter over the age of the solar system. The basic regularity of many of the giant planet satellite systems is probably due to other, perhaps primordial, causes.

Hubbard, W. B.↗
NASA NTRS1974

Polar motion and earth tides from Beacon Explorer C

Seventeen months of range data from a Goddard Space Flight Center laser tracking station are analyzed to determine the tidal perturbations in the orbit of the Beacon Explorer-C satellite and the variation in the tracking station latitude. The tidal perturbations are found to have a value 15% smaller than that derived from seismic studies, and the discrepancy is attributed to the combined effects of the solid earth and the oceans. The latitudinal variation is calculated with a standard deviation of 1.38 m to the smoothed BIH values and is shown to be due to the Chandler and annual motions of the pole.

Kolenkiewicz, R.↗
NASA NTRS1976

Earth tides, volcanos and climatic change

The effect of variations in tidal stresses on the earth caused by the sun and moon on volcanic activity and climate is investigated. A statistically significant correlation is found between the derivatives of the envelopes of peak tidal stresses at high northern latitudes and the mean temperature of the Northern Hemisphere as reflected in oxygen isotope ratios in the Greenland ice cap. It is suggested that variations in tidal stresses cause changes in the amount of stratospheric dust produced by volcanic activity, which affects the thickness of the stratospheric dust veil and the atmospheric radiation balance. For a simple model, periodic variations in tidal stress account for 13% of the variance in the ice-core temperature record.

Roosen, R. G.↗
NASA NTRS1977

A computer software system for the generation of global ocean tides including self-gravitation and crustal loading effects

A computer software system is described which computes global numerical solutions of the integro-differential Laplace tidal equations, including dissipation terms and ocean loading and self-gravitation effects, for arbitrary diurnal and semidiurnal tidal constituents. The integration algorithm features a successive approximation scheme for the integro-differential system, with time stepping forward differences in the time variable and central differences in spatial variables. Solutions for M2, S2, N2, K2, K1, O1, P1 tidal constituents neglecting the effects of ocean loading and self-gravitation and a converged M2, solution including ocean loading and self-gravitation effects are presented in the form of cotidal and corange maps.

Estes, R. H.↗
NASA NTRS1977

A computer software system for the generation of global ocean tides including self-gravitation and crustal loading effects

A computer software system is described which computes global numerical solutions of the integro-differential Laplace tidal equations, including dissipation terms and ocean loading and self-gravitation effects, for arbitrary diurnal and semidiurnal tidal constituents. The integration algorithm features a successive approximation scheme for the integro-differential system, with time stepping forward differences in the time variable and central differences in spatial variables.

Estes, R. H.↗
NASA NTRS1977

Planetary tides during the Maunder Sunspot Minimum

In order to test the tidal theory of sunspots, sun-centered planetary conjunctions and tidal potentials are reconstructed for the period of the Maunder Minimum (1645 to 1715). These are found to be effectively indistinguishable from patterns of conjunctions and power spectra of tidal potential in the modern era of a well-established 11-yr sunspot cycle. The pattern of planetary tidal forces during the Maunder Minimum is then reconstructed to investigate the possibility that multiple-planet forces were somehow fortuituously cancelled at that time; i.e., the positions of the slower moving planets in the late 17th and early 18th centuries were such that conjunctions and tidal potentials were reduced in number and force. Calculations of daily positions for Mercury, Venus, earth, and Jupiter as well as daily values of the tidal potential for the period from 1450 to 2000 indicate no striking dissimilarities between the time of the Maunder Minimum and any other period considered.

Smythe, C. M.↗
NASA NTRS1978

Open ocean tide modelling

Two trends evident in global tidal modelling since the first GEOP conference in 1972 are described. The first centers on the incorporation of terms for ocean loading and gravitational self attraction into Laplace's tidal equations. The second centers on a better understanding of the problem of near resonant modelling and the need for realistic maps of tidal elevation for use by geodesists and geophysicists. Although new models still show significant differences, especially in the South Atlantic, there are significant similarities in many of the world's oceans. This allows suggestions to be made for future locations for bottom pressure gauge measurements. Where available, estimates of M2 tidal dissipation from the new models are significantly lower than estimates from previous models.

Parke, M. E.↗