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791.
792.
L. Shakun N. Koshkin E. Korobeynikova D. Kozhukhov O. Kozhukhov S. Strakhova 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(6):1743-1760
With a growing number of resident space objects (RSOs), the facilities for near-Earth space surveillance have to cope with increasing workload. It also applies to low-cost small optical surveillance facilities which may present regional, national and global networks. Improved methods of planning and scheduling optical telescopes are required to use these instruments efficiently. Today, optical observations are only feasible if the following quite stringent requirements are met: the object should be illuminated by sunlight, and it should be above while the Sun is below the observer’s horizon. For different orbits, these preconditions result in varying degrees of the space object observability at various ground-based sites. Certainly, satellites in low Earth orbit (LEO) are particularly difficult to observe. This study aims at developing a new technique for assessing observability of a satellite in different types of orbits – namely, low, medium and high Earth orbits, imaging of the opportunity for its visibility in respective diagrams and their analysing for the existing near-Earth population of RSOs. Unlike other researches, wherein one or several observational stations have been chosen as target sites for in-depth analyses of visibility of all the satellites or just the selected ones, the present study focuses on examining the probability of optical surveillance of satellites in a certain orbit from any locations worldwide. It offers considerable scope for automation of surveillance planning and scheduling optical surveillance networks. 相似文献
793.
Cosmic Research - Features of the implementation of a beam-pulse amplifier (BPA) of whistler waves in magnetospheriс enhanced and depleted ducts with refraction reflection are considered.... 相似文献
794.
V. G. Dmitriev O. V. Egorova S. I. Zhavoronok L. N. Rabinskii 《Russian Aeronautics (Iz VUZ)》2018,61(2):165-174
In this paper, we develop the consistent mathematical models and appropriate lowconsuming numerical methods for investigating the nonlinear strain and buckling behavior of statically loaded thin-walled structures with cutouts. The numerical simulation allowed us to study the effects of the dimensions of rectangular cutouts on the buckling of cylindrical shells loaded by the external pressure. 相似文献
795.
O.H.库德尔雅绍夫 《航空精密制造技术》1999,35(6)
介绍了俄罗斯大型运载火箭壳体结构的材料。装配和焊接概况.对我国同类型航天火箭的制造有参考和借鉴意义. 相似文献
796.
N. A. Vlasova E. A. Ginzburg V. V. Kalegaev I. N. Myagkova M. I. Panasyuk I. A. Rubinshtein M. O. Riazantseva P. M. Svidsky V. I. Tulupov 《Cosmic Research》2013,51(5):319-325
Results of the comparative analysis of the dynamics of SCR fluxes with energies of 1–100 MeV in the interplanetary environment according to the data of the ACE and Wind spacecraft and within the Earth’s magnetosphere according to the data of the GOES-15 and Electro-L satellites in the region of geostationary orbits, and POES-19 and Meteor-M1 in the region of polar caps during two increases in SCR of January 19–31, 2012, are presented. It is shown that the decrease in the efficiency of SCR penetration into the Earth’s magnetosphere in the region of the orbits under study on January 28, 2012, is related to the passage of the Earth’s magnetosphere through the interplanetary environment structure with a quasi-radial interplanetary magnetic field and a small pressure of the solar wind. 相似文献
797.
The results of comparison of the characteristics of sharp boundaries of small-scale and medium-scale solar wind structures in the case of their simultaneous observation on widely spaced spacecraft are described. It is shown that even very sharp boundaries, with duration of several seconds or fractions of a second, retain their amplitude and remain very sharp during solar wind propagation to distances of up to a million kilometers. 相似文献
798.
799.
Harry O. Ruppe 《Space Policy》1987,3(2)
Fearing that mistaken decisions may be made, the author offers his comments to clarify the future possibilities for Ariane, Hermes and Columbus. The decisions soon to be taken on the manned spaceflight programme will affect the future of the entire European space programme. The possibilities for air-breathing propulsion are also reviewed. 相似文献
800.
Results of laboratory measurements of the dielectric characteristics of lunar soil samples returned to the Earth by the Luna and Apollo missions have been analyzed. The feasibility of determining the density of the upper cover of the Moon from the permittivity, which is restored as a result of solving the inverse problem of radiolocation, has been discussed. A formula has been proposed for approximating the frequency dependence of the loss tangent for the regolith and bedrock. Relationships have been deduced for estimating the percentage of metal oxides in the lunar soil. 相似文献