OPTIMIZATION OF ENERGY COSTS AT COMBINED WITHDRAWAL OF OBJECTS SPACE DEBRIS FROM LOW EARTH ORBITS

Abstract

The given article is devoted one of most acute problems of use of a space – clearing of low earth orbits from space debris. As one of ways of its solution is offered withdrawal of large objects of space debris in dense layers of atmosphere of the Earth with use of the propulsion system and an aerodynamic sail. The propulsion system supplies formation of an elliptical orbit of withdrawal with a perigee in an upper atmosphere, and an aerodynamic sail - gradual slowing down at the expense of effect on a sheaf «a withdrawal means - space object» forces of an aerodynamic drag of atmosphere. Obviously that efficiency of such method of withdrawal in many respects depends on a condition of the upper atmosphere which is function of solar activity. Hence, and energy expenses will depend not only on altitude of an initial orbit, ballistic factor, but also from a phase of solar activity at the moment of the beginning of withdrawal of space object, changing cyclically with the period in 11 years. On the basis of it is possible to draw a conclusion on repetition of change of energy expenses and minimum presence. The problem of minimization of energy expenses for withdrawal taking into account dynamically changing atmosphere of the Earth in the presence of limitations on lifetime is considered. For its solution imitating modeling of motion a sheaf «a withdrawal means - space object» in a near-earth space under the influence of gravity and an aerodynamic drag of atmosphere of the Earth is used. Parametric optimization of weight of the fuel components necessary for formation of an orbit of withdrawal with lifetime 25 years from circular orbits in altitude 500…1500 km, depending on a phase of solar activity at the moment of the beginning of withdrawal and ballistic factor is conducted. Areas of the minimum expenses of the fuel components supplying withdrawal are received. The estimation of efficiency of an offered combined method concerning withdrawal by actuation of propulsion system is executed. It is shown that combined withdrawal supplies economies of weight of fuel components in comparison with withdrawal by an orbital stage with propulsion system in limits from 20 % to 90 % depending on altitude of an initial orbit and ballistic factor.