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1.
We discuss a change in the resurfacing regimes of Venus and probable ways of forming the terrain types that make up the surface of the planet. The interpretation of the nature of the terrain types and their morphologic features allows us to characterize their scientific priority and the risk of landing on their surface to be estimated. From the scientific point of view, two terrain types are of special interest and represent easily achievable targets: the lower unit of regional plains and the smooth plains associated with impact craters. Regional plains are probably a melting from the upper fertile mantle. The material of smooth plains of impact origin is a well-mixed and representative sample of the Venusian crust. The lower unit of regional plains is the most widespread one on the surface of Venus, and it occurs within the boundaries of all of the precalculated approach trajectories of the lander. Smooth plains of impact origin are crossed by the approach trajectories precalculated for 2018 and 2026.  相似文献   
2.
Modern star trackers are based on photodetector arrays such as CCD or CMOS arrays. The accuracy of commercially available devices is ~1–3 arcseconds. However, the development of the space industry calls for higher orientation accuracies, which are needed in laser space communications, monitoring of near-Earth space and space debris, high-precision global mapping, and remote sensing of the Earth. The problems associated with enhancing the accuracy of modern star trackers are discussed.  相似文献   
3.
A second installment in a series of papers describing the technical basis for Soviet remote sensing from space focuses on the multispectral scanners of the “Meteor-Priroda” series of earth observation satellites. Designs of the various models are provided, as well as explanations of how such tasks as band separation, signal formation, and telemetry are performed. Translated from: Priroda Zemli iz kosmosa, A. P. Tishchenko and S. V. Viktorov, eds. Leningrad: Gidrometeoizdat, 1984, pp. 25-25-34.  相似文献   
4.
Solar System Research - We consider space expeditions with a long-term spacecraft stay near the studied celestial body (artificial satellites of small bodies of the Solar System), or expeditions...  相似文献   
5.
'Geology and Tectonics of Venus', special issue edited by Alexander T. Basilevsky (USSR Acad. Sci. Moscow), James W. Head (Brown Univ., Providence), Gordon H. Pettengill (M.I.T., Cambridge, Mass.) and R. S. Saunders (J.P.L., Pasadena).  相似文献   
6.

The development of a methodology for designing trajectories of spacecraft intended for the contact and remote studies of Jupiter and its natural satellites is considered. This methodology should take into account a number of specific features. Firstly, in order to maintain the propellant consumption at an acceptable level, the flight profile, ensuring the injection of the spacecraft into orbit around the Jovian moon, should include a large number of gravity assist maneuvers both in the interplanetary phase of the Earth-to-Jupiter flight and during the flight in the system of the giant planet. Secondly, the presence of Jupiter’s powerful radiation belts also imposes fairly strict limitations on the trajectory parameters.

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7.
A method for determining the celestial coordinates of the center of the disk of the Earth from satellite observations with an accuracy of 1–5 arcseconds is suggested. The choice of the most suitable wavelength range is substantiated.  相似文献   
8.
We describe goals and principles for the realization the Lyra-B space experiment onboard the International Space Station, which is currently being prepared at the Sternberg Astronomical Institute. The main goal of the experiment is to carry out a high-accuracy, multicolor all-sky survey of stars down to 16 m –17 m . The detailed structure of the expected observational data, their possible scientific use, and a number of technical problems are discussed.  相似文献   
9.
The article describes a model of the two-way measurements of radial velocity based on the Doppler effect. The relations are presented for the instantaneous value of the increment range at the time of measurement and the radial velocity of the mid-dimensional interval. The compensation of methodological errors of interpretation of the two-way Doppler measurements is considered.  相似文献   
10.
We describe the principles of the computation of minimum specifications of the optical system and array detector of the star attitude sensor to achieve the required attitude accuracy for the given exposure. The computations assume that the attitude error is influenced only by random noise of diverse origin, whereas all systematic errors have been eliminated. We report the specifications required for trackers meant for different purposes. We show that the errors of existing star trackers exceed the lowest achievable error by one order of magnitude because of unaccounted biases. We discuss the types of these biases and the methods that can be used to take them into account or eliminate them.  相似文献   
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