Ensuring the Safety of High-Orbit Spacecraf t Flights

Author(s):  
E. A. Pavlova ◽  
◽  
M. V. Zakhvatkin ◽  
A. I. Streltsov ◽  
L. V. Elenin ◽  
...  
Keyword(s):  
Author(s):  
A. M. Shamayev ◽  
M. D. Ozersky

The results of experimental studies of the effect of electron irradiation on K-208 and CMG glasses used for manufacturing protective coatings of solar batteries and thermal control coatings of space vehicles are analyzed. It is shown that the caused electrostatic discharges lead to structural changes in the surfaces of the glasses studied. The goals of further studies of the influence of proton and electronproton effects on the properties of such coatings are outlined. 


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Tao Shi ◽  
Xuebin Zhuang ◽  
Liwei Xie

AbstractThe autonomous navigation of the spacecrafts in High Elliptic Orbit (HEO), Geostationary Earth Orbit (GEO) and Geostationary Transfer Orbit (GTO) based on Global Navigation Satellite System (GNSS) are considered feasible in many studies. With the completion of BeiDou Navigation Satellite System with Global Coverage (BDS-3) in 2020, there are at least 130 satellites providing Position, Navigation, and Timing (PNT) services. In this paper, considering the latest CZ-5(Y3) launch scenario of Shijian-20 GEO spacecraft via Super-Synchronous Transfer Orbit (SSTO) in December 2019, the navigation performance based on the latest BeiDou Navigation Satellite System (BDS), Global Positioning System (GPS), Galileo Navigation Satellite System (Galileo) and GLObal NAvigation Satellite System (GLONASS) satellites in 2020 is evaluated, including the number of visible satellites, carrier to noise ratio, Doppler, and Position Dilution of Precision (PDOP). The simulation results show that the GEO/Inclined Geo-Synchronous Orbit (IGSO) navigation satellites of BDS-3 can effectively increase the number of visible satellites and improve the PDOP in the whole launch process of a typical GEO spacecraft, including SSTO and GEO, especially for the GEO spacecraft on the opposite side of Asia-Pacific region. The navigation performance of high orbit spacecrafts based on multi-GNSSs can be significantly improved by the employment of BDS-3. This provides a feasible solution for autonomous navigation of various high orbit spacecrafts, such as SSTO, MEO, GEO, and even Lunar Transfer Orbit (LTO) for the lunar exploration mission.


2021 ◽  
Vol 2 (6) ◽  
pp. 232
Author(s):  
Isamu Matsuyama ◽  
Antony Trinh ◽  
James T. Keane

Abstract The present ellipsoidal figure of the Moon requires a deformation that is significantly larger than the hydrostatic deformation in response to the present rotational and tidal potentials. This has long been explained as due to a fossil rotational and tidal deformation from a time when the Moon was closer to Earth. Previous studies constraining the orbital parameters at the time the fossil deformation was established find that high orbit eccentricities (e ≳ 0.2) are required at this ancient time, which is difficult to reconcile with the freezing of a fossil figure owing to the expected large tidal heating. We extend previous fossil deformation studies in several ways. First, we consider the effect of removing South Pole−Aitken (SPA) contributions from the present observed deformation using a nonaxially symmetric SPA model. Second, we use the assumption of an equilibrium Cassini state as an additional constraint, which allows us to consider the fossil deformation due to nonzero obliquity self-consistently. A fossil deformation established during Cassini state 1, 2, or 4 is consistent with the SPA-corrected present deformation. However, a fossil deformation established during Cassini state 2 or 4 requires large obliquity and orbit eccentricity (ϵ ∼ 68° and e ∼ 0.65), which are difficult to reconcile with the corresponding strong tidal heating. The most likely explanation is a fossil deformation established during Cassini state 1, with a small obliquity (ϵ ∼ −0.2°) and an orbit eccentricity range that includes zero eccentricity (0 ≤ e ≲ 0.3).


Author(s):  
Ю.Г. Пастернак ◽  
В.А. Пендюрин ◽  
К.С. Сафонов

Решение задачи связи в Арктике, а также в тундре, в тайге, в лесу, в море, на полях возможно только с использованием мобильных систем спутниковой связи. ФГУП «Космическая связь» (г. Москва) располагает группировкой спутников, которая постоянно расширяется. Для надежной связи в Арктике и в северных широтах, помимо геостационарных спутников, запущены спутники, движущиеся по высокоорбитальным траекториям. Для переключения со спутника на спутник, входящий в зону видимости абонента, необходимо использовать антенные решетки. Проблема заключается в том, что в настоящее время отсутствуют мобильные терминалы высокоскоростной спутниковой связи, а стоимость зарубежных аналогов препятствует широкому их использованию (достигает 50 тысяч долларов). Обычно радиолокационная связь (РЛС) с фазированной антенной решеткой используется для наблюдения за тысячами угловых точек, для отслеживания сотни целей. Такие требования могут быть выполнены только путем сканирования луча в пространстве в течение микросекунды. Ясно, что необходимо электронное управление лучом, поскольку механически вращать антенну не представляется возможным. Лишь некоторая часть вышеуказанных проблем будет затрагиваться в этой статье, ниже будут представлены электронная модель антенной решетки и её математическая модель The solution of the communication problem in the Arctic, as well as in the tundra, in the taiga, in the forest, in the sea, in the fields is possible only with the use of mobile satellite communication systems. FSUE "Space Communications" (Moscow) has a constantly expanding group of satellites. For reliable communication in the Arctic and Northern latitudes, in addition to geostationary satellites, satellites moving along high-orbit trajectories were launched. To switch from one satellite to the other included in the subscriber's visibility area, it is necessary to use antenna arrays. The problem is that currently there are no mobile terminals for high-speed satellite communication, and the cost of foreign analogues prevents their widespread use (up to 50 thousand dollars). Typically, a phased array radar is used to track thousands of corner points to track hundreds of targets. Such requirements can only be met by scanning the beam in space for a microsecond. It is clear, that electronic beam control is necessary since it is not possible to mechanically rotate the antenna. Only some of the above problems will be touched upon in this article. An electronic model of the antenna array and its mathematical model is presented


2020 ◽  
Vol 40 (13) ◽  
pp. 1311002
Author(s):  
王奇 Wang Qi ◽  
傅雨田 Fu Yutian

2017 ◽  
Vol 25 (10) ◽  
pp. 2584-2590
Author(s):  
高 扬 GAO Yang ◽  
赵金宇 ZHAO Jin-yu ◽  
刘俊池 LIU Jun-chi ◽  
杨晓霞 YANG Xiao-xia ◽  
王 斌 WANG Bin ◽  
...  
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