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The space programme of the former USSR has been in disarray since the disintegration of the Soviet empire and it faces formidable economic and political problems. Attempts are being made, however, to formalize a programme for the Commonwealth of Independent States (CIS) and a Russian space agency has been established. A senior Russian scientist here gives his personal view of the past, present and future of his country's space activities. He emphasizes the need to take advantage of new opportunities for cooperation, argues for the lifting of US restrictions on technology transfer and stresses the importance of space technology in monitoring environmental problems. This should remain a top priority.  相似文献   
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Dramatic changes in the world political situation have encouraged collaboration between the main spacefaring, and other nations, in furthering progress in space endeavours. General strategic concepts must balance scientific/ technology/cost rationales while still preserving political and ambitious issues. This paper advocates optimizing the information from low-cost robotic missions to outer and inner planets when discussing ambitious robotic and manned flights to Mars. The author also articulates three additional points: first, the necessity of establishing the degree to which a human rather than a robotic presence is an absolute requirement for the most effective study of a planet; second, is the time ripe for a manned mission to Mars considering existing political/economic/technological constraints?; and third, that such a costly project is justified only if nations pool their resources and combine interests through effective international cooperation.  相似文献   
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Fifty years ago, on October 1, 1966, the first Yantar satellite laboratory with a gas plasma–ion electric propulsion was launched into orbit as part of the Yantar Soviet space program. In 1966–1971, the program launched a total of four laboratories with thrusters operating on argon, nitrogen, and air with jet velocities of 40, 120, and 140 km/s, respectively. These space experiments were the first to demonstrate the long-term stable operation of these thrusters, which exceed chemical rocket engines in specific impulse by an order of magnitude and provide effective jet charge compensation, under the conditions of a real flight at altitudes of 100–400 km. In this article, we have analyzed the potential modern applications of the scientific results obtained by the Yantar space program for the development of air-breathing electric propulsion that ensure the longterm operation of spacecraft in very low orbits.  相似文献   
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From a critical comparison and synthesis of data from the four Pioneer Venus Probes, the Pioneer Venus Orbiter, and the Venera 10, 12, and 13 landers, models of the lower and middle atmosphere of Venus are derived. The models are consistent with the data sets within the measurement uncertainties and established variability of the atmosphere. The models represent the observed variations of state properties with latitude, and preserve the observed static stability. The rationale and the approach used to derive the models are discussed, and the remaining uncertainties are estimated.  相似文献   
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Numerical models of the thermal budget of the Earth's upper atmosphere in the height range of 90–500km are developed. The main sources and sinks of energy including infra-red radiative cooling by vibrational-rotational bands of NO, CO2, OH and O3 as well as heating and cooling arising from dissipation of turbulent energy and eddy heat transport are taken into account. The calculated temperature and density height profiles are in good agreement with the respective profiles from CIRA 72 and Jacchia 1977 models. It is shown for the models considered that IR-radiative cooling by CO2 and NO in the 15μ and 5.3μ bands, not eddy turbulence provides the major loss of heat from 90 to 180km.  相似文献   
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