Strangeness of translational and rotational motion of the geosynchronous object 10294 according to optical observations

Представлены особенности изменения параметров движения геосинхронного объекта 10294 SIRIO-1 №1977-080A по результатам оптических наблюдений в обсерваториях в Звенигороде, на пике Терскол и на горе Санглох республики Таджикистан. Пассивный итальянский научный космический аппарат SIRIO-1 представляет интерес тем, что он описывает классическую восьмерку вокруг точки либрации 75 ◦ в.д. без дрейфа по долготе и всегда доступен наблюдениям с наших пунктов. Это дает возможность детально исследовать поступательно-вращательное движение объекта, используя только результаты своих измерений. SIRIO-1 наблюдался нами для проверки аппаратуры и программного обеспечения как тестовый объект с очень устойчивой орбитой. В 2018 г. у этого объекта были обнаружены изменения в движении и в кривых блеска, не свойственные космическому мусору. Были зафиксированы небольшое скачкообразное изменение орбиты между 7 и 11 марта 2018 г. и изменение коэффициента отношения площади миделевого сечения объекта к его массе; кроме того перестал надежно определяться период изменения блеска и появилось характерное изменение блеска на одном и том же участке траектории с периодом, примерно равным звездным суткам. The features of changes in the motion parameters of the geosynchronous object 10294 SIRIO-1 No.1977-080A based on the results of optical observations at the observatories in Zvenigorod, Terskol Peak and Sanglokh Mountain in the Republic of Tajikistan are presented. The passive Italian scientific spacecraft SIRIO-1 is of interest to us because it describes the classic eight around the libration point of 75 ◦ E without longitude drift and is always available to observations from our observation points. This makes it possible to study in detail the translational-rotational motion of the object, using only the results of their measurements. SIRIO-1 was observed by us to test the hardware and software as a test object with a very stable orbit. In 2018, this object was found to have changes in motion and in the light curves that are not characteristic to space debris. A small abrupt change in the orbit between March 7 and 11, 2018, and a change in the area-to-mass ratio of the object were recorded. In addition, the period of change in the brightness was no longer reliably determined, and a characteristic change in the brightness appeared on the same part of the trajectory with a period approximately equal to the sidereal day.

ρ-Libration point in the three body problem

Herein, the restricted circular three-body problem in homogeneous and inhomogeneous media is considered. Particular attention is paid to libration points. The conditions of their existence or non-existence in the Newtonian and post-Newtonian approximations of the general theory of relativity are derived. Several regularities, new Newtonian and relativistic effects arising due to the impact of the additional relativistic forces on bodies of gravitational fields of mediums in the differential equations of the motion of bodies are indicated. Using the previously derived equations of the motion of two bodies A1, A2 in the medium, the authors substantiated the following statements. In a homogeneous medium (density of the medium ρ = const) in the Newtonian approximation of the general theory of relativity there are ρ-libration points , 1,...,5, moving along the same circles as the Euler and Lagrangian libration points Li but with an angular velocity 0 , greater than the angular velocity ω0 of libration points Li in a vacuum. Bodies A1, A2 also move along their circles with an angular velocity 0 > w When passing from the Newtonian approximation of the general theory of relativity to the post-Newtonian approximation of the general theory of relativity, the centre of mass of two bodies, resting in a homogeneous medium in the Newtonian approximation of the general theory of relativity, must move along a cycloid. The trajectories of the bodies can not be circles, the libration points Li disappear. In the case of an inhomogeneous medium distributed, for example, spherically symmetrically, the centre of mass of two bodies, already in the Newtonian approximation of the general theory of relativity, must move along the cycloid, despite it was at rest in the void. Therefore, bodies A1, A2 must describe loops that form, figuratively speaking, a «lace», as in the case of a homogeneous medium in the post-Newtonian approximation of the general theory of relativity. The figure illustrating the situation is provided. Due to the existence of the «lace» effect, the libration point Li movements are destroyed. In the special case, when the masses of bodies A1, A2 are equal (m1 = m2), the cycloids disappear and all the ρ-libration points exist in homogeneous and inhomogeneous media in the Newtonian and post-Newtonian approximations of the general theory of relativity. Numerical estimates of the predicted patterns and effects in the Solar and other planetary systems, interstellar and intergalactic mediums are carried out. For example, displacements associated with these effects, such as the displacement of the centre of mass, can reach many billions of kilometres per revolution of the two-body system. The possible role of these regularities and effects in the theories of the evolution of planetary systems, galaxies, and their ensembles is discussed. A brief review of the studies carried out by the Belarusian scientific school on the problem of the motion of bodies in media in the general theory of relativity is given.

Formation-Keeping Strategies At The Earth-Moon L4 Triangular Libration Point

This thesis examines the use of thrusters and solar sails for spacecraft formation keeping control at the Earth-Moon L4 point. Particular emphasis was placed on the study of underactuated control, in which fewer control inputs than the system's degrees of freedom are available. A linear LQR control scheme, an integral augmented sliding mode controller and a bang-bang controller were applied to the dynamic spacecraft system. The nonlinear controllers produced errors falling with tighter tolerances than the linear controllers in the perturbed environment. Performing similarly well as the underactuated thrusters system was the solar-sails-controlled spacecraft formation using a bang-bang controller. This shows that solar sails could be a viable propellantless technique for relative control. A linear control technique was able to bound errors to within a couple of hundred metres, using a hybrid propulsion system. Of the cases studied, only the fully-actuated thrusters-based system was able to explicitly track a circular trajectory, but had [Delta]V requirement of more than 100 times greater than that needed for tracking the natural, elliptical trajectory.

Formation-Keeping Strategies At The Earth-Moon L4 Triangular Libration Point

This thesis examines the use of thrusters and solar sails for spacecraft formation keeping control at the Earth-Moon L4 point. Particular emphasis was placed on the study of underactuated control, in which fewer control inputs than the system's degrees of freedom are available. A linear LQR control scheme, an integral augmented sliding mode controller and a bang-bang controller were applied to the dynamic spacecraft system. The nonlinear controllers produced errors falling with tighter tolerances than the linear controllers in the perturbed environment. Performing similarly well as the underactuated thrusters system was the solar-sails-controlled spacecraft formation using a bang-bang controller. This shows that solar sails could be a viable propellantless technique for relative control. A linear control technique was able to bound errors to within a couple of hundred metres, using a hybrid propulsion system. Of the cases studied, only the fully-actuated thrusters-based system was able to explicitly track a circular trajectory, but had [Delta]V requirement of more than 100 times greater than that needed for tracking the natural, elliptical trajectory.