Showing papers by "Jet Propulsion Laboratory published in 1969"

Stability of periodic orbits in the elliptic, restricted three-body problem.

Abstract: A systematic study has been made of periodic orbits in the two-dimensional, elliptic, restricted three-body problem. All ranges of eccentricities, from 0 to 1, and mass-ratios, from 0 to J, have been investigated. Eleven hundred periodic orbits have been obtained. It is concluded that the elliptic problem behaves in a way which is completely different from the circular problem. The main difference is in the stability properties of the periodic orbits. Because of the nonexistence of the Jacobi integral (the elliptic problem is not conservative), the characteristic equation of the monodromy matrix does not have a pair of unit roots, in general. The stability is denned by two real numbers (stability indices) rather than one. Because of that, there are seven general classes of periodic orbits, according to their stability properties. The stability of the periodic orbits has been determined by numerically integrating the variational equations with a recurrent power series method. The results are in contrast with the circular problem, where there are only three classes of orbits (stability, even instability, and odd instability): in the elliptic problem there are one stable class and six unstable classes. The elliptic, restricted three-body problem can be considered as the prototype of all nonintegrable, nonconservative Hamiltonian systems, and in this paper, probably for the first time, a classification of the multipliers is given for these systems. I. Introduction

Transonic flowfield in a supersonic nozzle with small throat radius of curvature.

Abstract: Internal flow measurements in transonic region of supersonic nozzle with small throat radius of curvature compared with prediction data

Extension of square-root filtering to include process noise

Abstract: Two different square-root filters, one obtained by Potter and the other employing Householder transformations, are extended to include process noise. The relative numerical accuracy of various sequential filters is explored with several examples.

Mariner 6: ultraviolet spectrum of Mars upper atmosphere.

Abstract: Emission features from ionized carbon dioxide and carbon monoxide were measured in the 1900- to 4300-angstrom spectral region. The Lyman alpha 1216-angstrom line of atomic hydrogen and the 1304-, 1356-, and 2972-angstrom lines of atomic oxygen were observed.

Rank permutation group codes based on Kendall's correlation statistic

Abstract: A coding scheme based on the properties of rank vectors is presented. The new codes are based on the theory of permutation groups by introducing a new notation for the group operation that simplifies the generation and decoding of desirable rank codes. The use of group theory is made possible by the introduction of the Kendall correlation coefficient as a measure of the distance between code words. This technique provides a method for the choice of rank vector code words superior to those that have been proposed in the past. Much of the terminology used in block coding can also be used to describe rank vector codes, but the actual quantities involved are quite different. The rank vector codes discussed in the paper offer the advantage of low sensitivity of the probability of error to the noise distribution because of the nonparametric character of rank vector detection schemes. Bounds that have been verified by extensive computer simulation have been derived for the probability of error.

Mariner 6 and 7 television pictures: preliminary analysis.

Abstract: Before the space era, Mars was thought to be like the earth; after Mariner 4, Mars seemed to be like the moon; Mariners 6 and 7 have shown Mars to have its own distinctive features, unknown elsewhere within the solar system.

Chemical composition of the lunar surface in mare tranquillitatis.

Abstract: More precise and comprehensive analytical results have been derived for lunar material at the Surveyor V landing site from alpha-scattering data. The composition is, in general, basaltic; the low sodium and high titanium contents, however, are distinctly different from the abundances in meteorites or common terrestrial rocks.

Efficient solution of load-deflection equations.

Abstract: Load deflection equation solution based on row operations, involving three passes of coefficient matrix, using wavefront processing and modified Gauss algorithm

A programming system for analytical series expansions on a computer

Abstract: A programming system is described for the manipulation of Poisson series on a computer. The general structure is described together with the most important individual subroutines. The system exists in two versions, one with 3 angular and 3 polynomial variables and the other with twice as many variables. The programming has been done first in FORTRAN IV, but the most crucial subroutines have been rewritten in machine language for more efficiency. The storage mechanism is such that obsolete series can be erased from the main memory in order to make room for new series to be created.

Estimation of Solubility Parameters from Refractive Index Data

Abstract: THE solubility parameter, δ, of a polymer or compound is a measure of intermolecular forces and is useful for the studies of many polymer characteristics, particularly glass transition temperatures1, solubilities and diffusion or transport properties.2 It is therefore highly desirable to have a convenient method for quickly estimating δ values of polymers. It was suggested by Hildebrand and Scott, and later by Scatchard, that solubility parameters could be calculated from optical data such as refractive index measurements3,4. In this article we report some semiempirical correlations between solubility parameters and refractive indices for a series of model compounds and polymers. This work refers only to hydrocarbon and other organic materials; further work would be required to determine if an extension to inorganic polymers is possible.

Heat detection and compositions and devices therefor

Abstract: TEMPERATURE CHANGE OF A SUBSTRATE SUCH AS A MICROELECTRONIC COMPONENT IS SENSED AND DETECTED BY MEANS OF A MIXTURE OF A WEAK MOLECULAR COMPLEX OF AN ELECTRON DONOR COMPOUND SUCH AS AN ORGANIC AMINE AND AN ELECTRON ACCEPTOR COMPOUND SUCH AS NITROAROMATIC COMPOUND. THE MIXTURE IS ENCAPSULATED IN A CLEAR BINDER SUCH AS A VINYL RESIN.

Relative intensity calculations for carbon dioxide. IV - Calculations of the partition function for isotopes of CO sub 2.

Abstract: Relative intensities of lines in vibration and rotation bands of isotopic carbon dioxide in planet Venus, tabulating partition functions

A simplified approach for determining the information content of radio tracking data.

Abstract: Navigational accuracy dependence on spacecraft geometry, determining information content and critical error sources of earth based Doppler radio tracking data

Mariner 1969: Preliminary Results of the Infrared Radiometer Experiment

Abstract: The thermal energy emitted by Mars was measured in the 8- to 12- and 18- to 25-micrometer bands The minimum temperature derived for the southern polar cap is 150°K, an indication that the cap is formed by frozen carbon dioxide No significant temperature fluctuations were detected with a 100-kilometer scale

Electrostatic rocket exhaust effects on solar- electric spacecraft subsystems

Abstract: Electrostatic rocket exhaust condensation on spacecraft solar electric panels cover glasses, noting deleterious effects

Flow and Heat Transfer in Laminar Boundary Layers with Swirl

Abstract: Superimposed free vortex swirl effect on flow and heat transfer in three dimensional axisymmetric laminar boundary layer

High Dispersion Spectroscopic Observation of Venus. IV: The Weak Carbon Dioxide Band at 7883 A.

Abstract: The average rotational temperature of the Cytherean atmosphere above the cloud tops was found to be Trot = 244 ± 10 K based on twelve plates of the 7883-A CO2 band. If the temperatures found from the 7820-A band on the same plate are averaged with the temperatures found from the 7883-A band, we obtain a temperature of Trot = 245 ± 6 K. The observations of Venus were made between April and December of 1967. Laboratory measurements of the 7883-A band are lacking, but we infer that the band is half as strong as the 7820-A band.

On the Internal Structures of Mercury and Venus

Abstract: Recent radar measures of the radius and mass of Mercury imply a composition for the planet containing about 60% iron. One or other of two conclusions seems inescapable: either that Mercury is a highly exceptional object among terrestrial planets, or that all measures to date of the planet involve substantial systematic error. In either case the situation is such that independent checking of the radius and mass of Mercury by some entirely different means has become of the greatest importance to planetary physics and cosmogony. The recent radar and other determinations of the solid radius of Venus imply an internal structure similar to that of the Earth, namely a liquid core surrounded by a solid mantle and outer-shell zone. The theory also implies that the temperatures within Venus should be slightly higher than at the corresponding parts of the Earth. The proportion of mass in the core of Venus (about 25% of the whole) is entirely consistent with the phase-change hypothesis as to its nature, as of course is also the absence of any liquid or iron core in both Mars and the Moon. On the older iron-core hypothesis, Venus with considerably less iron content by mass than the Earth, and Mars and the Moon with none, would all present problems in different degrees to account for the differences of composition. If Venus began as an all-solid planet, the initial radius would have been about 6300 km, and the total amount of surface reduction to date owing to contraction of the planet would have been almost 40 million km2, and as a proportion of the total area only slightly less than the contraction of the Earth. The theory thus predicts the existence of folded and thrusted mountain-systems of terrestrial type at the surface of Venus.

Thermomagnetic recording and magneto-optic playback system

Abstract: A magnetic recording and magneto-optic playback system is disclosed wherein thermomagnetic recording is employed. A transparent isotropic film is heated along a continuous path by a focused laser beam. As each successive area of the path is heated locally to the vicinity of its Curie point in the presence of an applied magnetic field, a magneto-optic density is established proportional to the magnetic field and fixed in place as the area cools once the laser beam moves on to an adjacent area. The magnetic field is varied by an input signal so that the magnetooptic density established in a given area of the film is proportional to the amplitude of the input signal being applied. To play back the recorded data, the intensity of the laser beam is reduced to avoid reaching the vicinity of the Curie point of the film as it is scanned by the laser beam in the same manner as for recording. A Faraday effect analyzer and photo detector are employed as a transducer for producing an output signal.

Mariner 6 television pictures: first report.

Abstract: In July 1965, Mariner 4 flew past Mars and recorded 20 television pictures of the martian surface; the principal television result of that pioneering flight was the discovery that Mars' surface is heavily cratered and resembles the Moon more than it does the Earth (1). On 31 July 1969, the more advanced Mariner 6 spacecraft, carrying two television cameras, passed Mars and recorded 75 pictures. A twin spacecraft, Mariner 7, passed Mars on 5 August 1969. This report summarizes the results of a first, qualitative study of the Mariner 6 television pictures, carried out on the uncalibrated data within a few days after receipt on Earth.

Ion-molecule reactions in hydrogen cyanide.

Abstract: Gas phase ion-molecule chemistry of HCN by ion- cyclotron resonance spectroscopy identifying individual reactions by double resonance

Submicron Structure of ``Amorphous'' Opal

Abstract: THE precious variety of opal, a hydrous colloidal form of silica, is iridescent. Explanations have been offered of the origin of the observed play of colours1,2, some including the most recent optical diffraction evidence3. Electron microscope studies were thought to indicate that the colours may originate from spherical silica particles arranged hexagonally in layers of predominantly random stacking. The studies also contributed measurements of particle diameter and approximate shape4–6. Replication difficulties of sample preparation, however, inhibited these investigations, particularly affecting the search for three-dimensional information.

Electromagnetic velocity-transducer studies of plastic waves in aluminum bars

Abstract: In this investigation, annealed aluminum rods were subjected to dynamic compressive impact loading of duration of the order of 560 μsec to study the propagation of longitudinal plastic waves, using an electromagnetic transducer to record particle velocities at four stations approximately three inches apart. Test results indicate that any given level of particle velocity propagates along the bar with a constant speed, not affected by the strain rate, within the range of strain rates encountered. Good agreement was found between the propagation speeds observed for different levels of velocity (averaged over all tests) and predictions of the von Karman rate-independent plastic-wave-propagation theory based on a single dynamic stress-strain curve almost coinciding with the static curve.