排序方式: 共有117条查询结果,搜索用时 15 毫秒
61.
M.?Yu.?OvchinnikovEmail author V.?I.?Pen’kov D.?S.?Roldugin S.?O.?Karpenko 《Cosmic Research》2012,50(2):170-176
We consider the rapid rotation of a satellite equipped with an active magnetic attitude control system with the -Bdot algorithm designed to damp the initial angular velocity. The time-response of the algorithm is analytically studied as a
function of orbit inclination. 相似文献
62.
The results are given of the theoretical calculations and the results of measurements of the shape of the reflecting surface of the space telescope conducted during the manufacture of individual elements and assembly of the product as a whole. 相似文献
63.
The accelerations that emerge in the disk wing during rotation have been found. The loading of wing elements have been determined when the blades are extended and retracted. 相似文献
64.
65.
The problem of the optimal spacecraft’s insertion from the Earth into the high circular polar Moon Artificial Satellite’s orbit (MAS) with a radius of 4000–8000 km has been investigated. A comparison of single- and three-impulse insertion schemes has been performed. The analysis was made taking into account the disturbances from the lunar gravity field harmonics and the gravity fields of the Earth and the Sun, as well as the engine’s limited thrust. It has been shown that the three-impulse transfer from the initial selenocentric hyperbola of the approach into the considered final high MAS orbit is noticeably better with respect to the final mass than the ordinary single-impulse deceleration. The control parameters that implement this maneuver and provide nearly the same energy expenses as in the Keplerian case have been presented. It was found that, in contrast to the Keplerian case, in the considered case of the real gravity field, there is the optimal maximum distance of the maneuver. Recently, the Moon exploration problem became actual again. 相似文献
66.
The direction of the twilight sky background polarization on the celestial sphere far from the solar vertical depends on the ratio of single and multiple scattering contributions. Variations in the polarization direction during twilight reflect the evolution of the properties and background emission components and can be used to control the procedure of selecting single scattering. This makes it possible to specify the temperature measurements according to the molecular scattering of solar emission and the contribution of dust scattering in the upper mesosphere. The results of the temperature measurements during the observations in 2011–2015 have been presented. 相似文献
67.
V.?I.?Kovalev Yu.?Ya.?RuzhinEmail author Yu.?A.?Plastinin B.?A.?Khmelinin 《Cosmic Research》2017,55(5):338-344
The spectral curve of the flux density of the radiation, which is reflected by the full moon towards the Earth’s ionosphere within a wavelength range of 200–1700 Å, has been presented. This curve is obtained by the approximation of space experiment data available in the scientific literature on the lunar spectral albedo and solar spectrum. Estimates of maximum values of spectral densities of fluxes reflected by the full moon in the neighborhood of wavelengths of ionization of basic ionospheric particles (neutral atoms of H I, He I, N I, O I, and Ar I and ions of He II, N II, O II, Ar II, N III, O III, and Ar III, as well as molecules of H2, N2, and O2) are given. 相似文献
68.
V.?G.?EselevichEmail author N.?L.?Borodkova O.?V.?Sapunova G.?N.?Zastenker Yu.?I.?Yermolaev 《Cosmic Research》2017,55(6):403-416
Based on the data of the BMSW instrument installed on the of SPEKTR-R spacecraft, as well as according to the data of instruments of the WIND spacecraft, etc., using two examples, the paper has studied the role of ions reflected from the front and associated structural features of quasi-perpendicular interplanetary shocks (IS) with the Alfvén Mach number М A lower than the first critical Mach number М c1 . It has been shown that BSs with the finite parameter 0.1 < β1 < 1 contain a small fraction of reflected protons, which play a significant role in forming the front structure (β1 is the ratio of gas-to-magnetic pressure before the shock front). In particular, in the case of a perpendicular shock recorded on August 24, 2013 (the angle between the magnetic field direction and the normal to the front θBn ≈ 85°), an IS with a small Mach number (МA ≈ 1.4) and small β1 ≈ 0.2 is shown that the interactions of reflected ions with inflowing solar wind may result in the collisionless heating of ions in front of and behind it. The case of the oblique (θBn = 63°) IS on April 19, 2014 with a small Mach number (М A ≈ 1.2) and small β1 ≈ 0.5 has been investigated. It has been found that, before the front, there is a sequence of trains of magnetosonic waves, the amplitude of which decreases to zero upon increasing their distance from the front. The mechanism of their formation is associated with the development of instability caused by the ions reflected from the front. 相似文献
69.
Zh.?V.?DashkevichEmail author V.?E.?Ivanov T.?I.?Sergienko B.?V.?Kozelov 《Cosmic Research》2017,55(2):88-100
A physicochemical model of excited polar ionosphere has been presented. The model makes it possible to calculate vertical profiles of concentrations of the following excited and ionized constituents: O2 +, N2 +, O+(4S), O+(2D), O+(2P), O(1D), O(1S), N(4S), N(2D), N(2P), NO, NO+, N+, N2(A3Σu +), N2(B3Пg), N2(W3Δu), and N2(B′3Σu -) and the electron concentration during electron precipitations. The energy spectrum of the electrons at the upper boundary of the ionosphere and concentrations of neutral constituents are the input parameters of the model. A model has been compiled based on available publications and includes 56 physicochemical reactions that influence concentrations of the aforementioned constituents in the polar ionosphere. The method of calculating vertical profiles of the excitation rates of atmospheric gases and proper allowance for the electron-vibrational kinetics in the processes of exciting the triplet states of N2 are specific features of the presented model. The ionospheric model has been approbated using the results of the coordinated rocket–satellite experiment. The agreement between the modeling results and experimental data best for the time being is achieved. 相似文献
70.
The possibility of the spacecraft insertion into the system of operational heliocentric orbits has been analyzed. It has been proposed to use a system of several operational heliocentric orbits. On each orbit, the spacecraft makes one or more revolutions around the Sun. These orbits are characterized by a relatively small perihelion radius and relatively high inclination, which allows one to investigate the polar regions of the Sun. The transition of the spacecraft from one orbit to another has been performed using an unpowered gravity assist maneuver near Venus and does not require the cruise propulsion operation. Each maneuver transfers the spacecraft into the sequence of operational heliocentric orbits. We have analyzed several systems of operational heliocentric orbits into which the spacecraft can be inserted by means of the considered transportation system with electric propulsion (EP). The mass of the spacecraft delivered to these systems of operational orbits has been estimated. 相似文献