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661.
The dynamics of a satellite-gyrostat moving in the central Newtonian force field along a circular orbit is studied. In the particular case when the vector of gyrostatic moment is parallel to one of the satellite’s principal central axes of inertia, all the equilibrium states are determined. For each equilibrium orientation, sufficient conditions of stability are obtained as a result of the analysis of the generalized energy integral, and necessary conditions of stability are determined as a result of analysis of the linearized equations of motion. The evolution of regions of validity for the conditions of stability of equilibrium positions are studied in detail depending on the parameters of the problem. All the bifurcation values of the parameters at which qualitative changes of the regions of stability take place are determined.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 4, 2005, pp. 283–294.Original Russian Text Copyright © 2005 by Sarychev, Mirer, Degtyarev. 相似文献
662.
Yu.A. Surkov V.L. Barsukov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(8):17-29
Physical and mechanical properties as well as chemical and mineral composition of Venus rocks are discussed on the basic of the data obtained by ground-based radar observations and the experiments in situ. 相似文献
663.
U. von Zahn V.I. Moroz 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(11):173-195
Our current knowledge on the composition of the Venus atmosphere in the altitude range from the surface to 100 km is compiled. Gases that have been measured, and whose mixing ratios are assumed to be constant with altitude, are CO2, N2, He, Ne, Ar, and Kr. Gases that have been identified in the lower and/or middle atmosphere, but whose mixing ratios may depend on altitude, latitude and/or local time, are CO, H2O, HCl, HF, and SO2. Conflicting data or only upper limits exist on some important trace gases, such as O2, H2, and Cl2. The latter two are key constituents in the photochemistry of the middle atmosphere of Venus. The chapter concludes with a listing of the isotopic abundances of elements measured in the Venus atmosphere. 相似文献
664.
N.V. Jorjio R.A. Kovrazhkin M.M. Mogilevsky J.M. Bosqued H. Rème J.A. Sauvaud C. Béghin J.L. Rauch 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(4):141-144
The plasma diagnostic experiments on the AUREOL-3 satellite have revealed flows of low energy 0+ ions deep inside the night plasmasphere during a large substorm. Flux gradients of the 0+ ions were accompanied by enhancements of ELF electric field noise. The appearance of suprathermal ions at is interpreted within the framework of electrostatic ion-cyclotron acceleration of ionospheric ions in the diffuse auroral zone /12/ followed by a radial displacement of these ions inside the plasmasphere driven by azimuthal electric fields during substorm activity. Electrostatic oscillations observed inside the plasmasphere are apparently associated with gradient instability at the sharp boundaries of suprathermal ion flows. 相似文献
665.
V.N. Chelomey 《Acta Astronautica》1984,11(5):269-273
New paradoxical phenomena encountered during experiments with vibrating fluids and solid bodies are reviewed. 相似文献
666.
I V Gribovskaya I A Gladchenko G K Zinenko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(4-5):93-97
Two methods of extracting mineral elements from otherwise deadlock products of a life-support system are presented. We describe first optimum conditions for recovering elements by water extraction from dry wastes of plants, biomass ash, and solid human wastes after passing them through the catalytic furnace; and, second, we describe acid extracts of biogenous elements by 1N and 2N HNO3 from these products. Ways to use the extracts of elements in plant nutrition are considered in order to increase the extent to which the mineral loop of a life-support system can be closed. 相似文献
667.
The Satellite Instructional Television Experiment (SITE) was a unique effort aimed at studying the possibilities of satellite broadcasting for education and national development. This one-year joint India-USA project was carried out in 1975–1976 using the ATS-6 spacecraft. This paper briefly describes the experiment and its major findings. It goes on to distill the learning experiences derived from SITE and analyses the extent to which these have influenced the design and configuration of India's domestic satellite system, INSAT. INSAT-1B, which will serve as a replacement for the short-lived INSAT-1A, will be launched shortly and will be operational by the end of 1983. Its payload includes two S-band TV transponders capable of broadcasting directly to augmented TV sets. The paper examines which lessons of SITE are being applied in the planning and operationalisation of the TV system and discusses why others are not being taken account of. Major issues confronting TV system planners in developing countries like India are highlighted and the possible role of satellite broadcasting discussed in this context. The paper concludes by outlining an “ideal scenario” for a large, multilingual country like India, towards which TV planners could attempt to strive. 相似文献
668.
V I Trofimov A Victorov M Ivanov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(1-2):333-337
Two tasks must be accomplished to provide planetary protection for Mars return missions: (1) sterilization of the scientific module to be landed on Mars and (2) reliable sterilization of all material returned to Earth, while ensuring the scientific integrity of martian samples. This paper examines similarity and differences between these two tasks, and includes a discussion of technological implementation conditions and the nature of terrestrial and hypothesized martian microflora. The feasibility of a number of chemical and physical (ultraviolet and ionizing radiation and heating) methods of sterilization for use on the ground and onboard are discussed and compared. A combination of different methods will probably be selected as the most appropriate for ensuring planetary protection on the return mission. 相似文献
669.
670.
The magnetizing inductance of the isolated Cuk converter introduces an undesirable pair of closely spaced complex zeros and poles, or a glitch, in the control-to-output transfer function. Limited analysis and experimentation in the past have shown that sufficient increase in the magnetizing inductance or manipulation of the ratio of the capacitances of the energy transfer capacitors can reduce the glitch. In this work, the isolated Cuk converter with coupled input and output inductors has been studied and the dependence of the glitch on various circuit parameters has been determined analytically. A condition has been derived for the ratio of the capacitances of the two energy transfer capacitors which completely eliminates the glitch at a given operating point. With this condition satisfied, it is shown that the energy transfer capacitors can be easily damped by a simple RC network to eliminate the glitch from a wide range of operation about an operating point 相似文献