Перегляд за Автор "Melikyants, S. M."

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  • Ескіз
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    Atlas of light curves of space objects
    (2021) Koshkin, Mykola I.; Shakun, Leonid S.; Korobeinikova, E. A.; Strakhova, S. L.; Melikyants, S. M.; Terpan, S. S.; Golubovskaya, T. A.; Dragomiretsky, V. V.; Ryabov, A. V.; Кошкін, Микола Іванович
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    LIGHT POLLUTION IN LEO-SATELLITE TRACKING
    (Astroprint, 2015) Shakun, Leonid S.; Marsakova, V. I.; Golubovskaya, T. A.; Terpan, S. S.; Melikyants, S. M.; Korobeinikova, E. A.
    Because of the high level of the light pollution in Odessa city, only the observations of LEO (low Earth orbit)-satellites are performed in the main office of the Astronomical observatory of Odessa National University named after I.I. Mechnikov. As the one of the observation results we obtain the sky background measurements along the satellite’s way through the sky (at different azimuths and altitudes that change during the satellite tracking). We propose the method of irregular extinction changes diagnostics that realized by using the different data filtration methods. Also as the result of our analysis of these observations we present azimuth-altitude diagram of sky background that shows the most significant light pollution at the north-western and northern directions caused by the Port of Odessa and the stadium “Chernomorets”.
  • Ескіз
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    Monitoring of space debris rotation based on photometry
    (Одеський національний університет імені І. І. Мечникова, 2018) Koshkin, Nikolay I.; Shakun, Leonid S.; Korobeinikova, E. A.; Melikyants, S. M.; Strakhova, S. L.; Dragomiretsky, V. V.; Ryabov, A. V.; Golubovskaya, T. A.; Terpan, S. S.; Кошкин, Николай Иванович; Кошкін, Микола Іванович
    The number of spacecraft and space debris (SD) in orbit has become so great that there is a real threat to flight safety. The task of precision calculation of the upcoming positions of any space objects (SO) in orbit in order to predict dangerous mutual approaches and to solve practical tasks has become topical. For the development of a modern orbit propagation model and the associated unified forecast of the evolution of orientation and rotation of an uncontrolled satellite, it is necessary to rely on long-term series of high-quality measurements and their analysis. At present, the direction of research on determining the state of SO rotation around a center of mass has become more and more developed. In our work, we analyze the results of photometric observations of several large objects of space debris obtained at the Astronomical Observatory of Odessa University using the KT-50 telescope during the last six years or more. The results of the evolution of the rotation rate and orientation of the Topex/Poseidon, Envisat, Oicets, Cosmos-2487 (Kondor- E) and Sich-2 satellites are presented.
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    Monitoring of the inoperative Envisat satellite’s behaviour
    (Astroprint, 2013) Shakun, Leonid S.; Koshkin, Nikolay I.; Korobeinikova, E. A.; Melikyants, S. M.; Strakhova, S. L.; Terpan, S. S.; Кошкин, Николай Иванович; Кошкін, Микола Іванович
    New positions data and light curves were received for the inoperative Envisat spacecraft still in orbit. The satellite pole and sidereal rotation period were determined on the base of the photometric data for the period from April to August 2013. The presence of a precession of the Envisat rotation axis was deduced.
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    Simulation of the orbiting spacecraft to analysis and understand their rotation based on photometry
    (Одеський національний університет імені І. І. Мечникова, 2019) Koshkin, Nikolay I.; Melikyants, S. M.; Korobeinikova, E. A.; Shakun, Leonid S.; Strakhova, Svitlana I.; Kashuba, V.; Romanyuk, Ya.; Terpan, S. S.; Кошкін, Микола Іванович; Кошкин, Николай Иванович; Шакун, Леонід С.
    Analysis of the photometric information allows to determine the parameters of spacecraft rotation. We will consider the light curves of a rotating satellite. Smooth changes in brightness, which are caused by diffuse scattering of sunlight, are characterized by the amplitude, quantity, shape and asymmetry of brightness variation during the rotation period of the body. In addition, the so-called “specular” flashes of light of very large amplitude are present on light curves. By analyzing the observed light curves of the inactive satellites Topex/Poseidon and Sich-2, the determination of pole orientation these objects in space is demonstrated. To interpret the light curve's contained information, we are planning to creat optical-geometrical models of this satellite and simulated geometrical conditions by its orbit passages. Further comparison of the model and observed light curves should allow us to confirm the correctness of the satellite attitude determination. For the simulation, we used the MaxScript programming language, which allows to create a satellite model, and simulate the opticalgeometric conditions of its passage, including the complex rotation of the spacecraft.
  • Ескіз
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    The observations of artificial satellites and space debris using KT-50 telescope in the Odessa University
    (Одеський національний університет імені І. І. Мечникова, 2016) Shakun, Leonid S.; Koshkin, Nikolay I.; Korobeinikova, E. A.; Melikyants, S. M.; Strakhova, S. L.; Terpan, S. S.; Burlak, N.; Golubovskaya, T. A.; Dragomiretsky, V. V.; Ryabov, A. V.; Кошкин, Николай Иванович; Кошкін, Микола Іванович
    In paper the equipment, images analysis techniques in the frame and the method of the satellite brightness estimation in the standard photometric system are describes. Within two years, on the KT-50 telescope were obtained measurements of about two hundred objects in more than 2,000 passages. The results of statistical analysis of actual data observations array in 2015 and 2016 are given.
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    The photometric model of artificial satellite AJISAI and determination of its rotation period
    (Astroprint, 2012) Korobeinikova, E. A.; Koshkin, Nikolay I.; Shakun, Leonid S.; Burlak, N.; Melikyants, S. M.; Terpan, S. S.; Strakhova, S. L.; Кошкин, Николай Иванович; Кошкін, Микола Іванович
    ABSTRACT. Photometry is used to make remote diagnostics of an artificial satellite’s motion around its centre of mass. Experimental satellite Ajisai was designed to explore the effects of the space factors, such as gravitation and magnetic fields, solar radiation and others, on its orbital motion and rotation. In the present study we consider the use of peculiar light curves of Ajisai, exhibiting a complex sequence of momentary flashes, for precise determination of the rotation period and velocity variations. For the first time, on the basis of the high-speed photometry, the model of placement of mirrors on the satellite’s surface was designed to carry out further analysis of its kinematics.
  • Ескіз
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    The research of variation of the period and precession of the rotation axis of Egs (Ajisai) satellite by using photometric measurement
    (Astroprint, 2014) Burlak, N.; Koshkin, Nikolay I.; Korobeinikova, E. A.; Melikyants, S. M.; Shakun, Leonid S.; Strakhova, S. L.; Кошкин, Николай Иванович; Кошкін, Микола Іванович
    The light curves of EGS Ajisai with temporal resolution of 20 ms referred to the time scale UTC (GPS) with an error of at most 0.1 ms were obtained. The observed flashes are produced when the mirrors which cover the spinning satellite’s surface reflect off the sunlight. In previous paper the analysis of sequence of flashes allowed of reconstructing the arrangement and orientation of the mirrors, i.e. developing an optogeometric model of the satellite (Korobeynikova et al., 2012), and to apply that model along with new photometric observations to determine the satellite’s sidereal rotational period with an accuracy that was previously unachievable. A new technique for determination of the spin-axis orientation during each passage of the satellite over an observation site was developed. The secular slowdown of the satellite’s spin rate (Рsid = 1.4858EXP(0.000041099T), where Т is measured in days counted from the date of the satellite launch) and its variations correlating with the average duration of the satellite orbit out of the Earth’s shadow were refined. New parameters of the spin-axis precession were estimated: the period Pprec = 116.44 days, αprec = 18.0h, δprec = 87.66°, the nutation angle θ = 1.78°.