Earth and the near-space: research, discoveries, and problems

1Rykhlova, LV
1Institute of Astronomy of the Russian Academy of Sciences, Moscow, Russia
Space Sci.&Technol. 2018, 24 ;(4):71-76
Publication Language: Russian
60 years have passed since the launch of the first artificial Earth satellite. During this time the space research has turned into one of the most dynamic and fruitful areas of science, developing in numerous fields - from the study of the atmosphere, space geodesy and Earth remote sensing to the study of the Universe in the whole spectrum of electromagnetic waves. In the article, the attention is paid to the emerging possibility of using the observations of satellites as targets for the studies of the Earth: its shape and gravitational field, the definition of fundamental astrometric and geodesic constants, determination and study of parameters of the Earth’s rotation.
         The necessity of reviewing the principles and methods of construction of basic reference frames has emerged. We briefly summed up  the main stages of high-precision determinations of parameters of the Earth’s gravitational field with the  help of the specialized satellites, as well as an effect of deviations of the Earth from the uniformly rotating solid body on the satellite orbits, changes in the speed of the Earth’s rotation. Satellites provide direct and accurate measurements of the Earth's flattening, data of its internal structure, terrestrial tides, and plate tectonics. The new problem has arisen, which is related to the intensive exploration of the near-Earth space. More than 50 countries participate in its exploration. The space industry has become an integral part of the world economy. The number of satellite launches for various purposes is now approaching 6000. Parts of launch vehicles, defunct satellites and their disintegration create the growing amount of space debris in the near-Earth space, which already poses a threat to space exploration. In this connection, the new research field arises in astronomy - the observation of the technogenic space debris, studying its distribution over the altitudes of orbits, its density at various altitudes, determination of its sizes, velocity and direction of its movement. All this leads to the development of methods and means of space debris removal from the near-Earth space to continue the space exploration.
Keywords: near-Earth astronomy, near-Earth space, optical observations, space debris