Gravitation effect on a flux of sporadic micrometeoroids in the vicinity of near-Earth orbits

The new approach to gravitation effect determination in calculating the flux of sporadic micrometeoroids in the near-Earth space is proposed. The technique is based on integration of the equations of motion of sporadic micrometeoroids with accounting for bending their trajectories when particles are approaching the Earth. The technique and results of calculation of the gravitational focusing factor k_g for various conditions are presented. The feature of the proposed technique for calculating coefficient k_g consists in the fact that this coefficient does not explicitly depend on the values of particles velocity at the last point. The results of investigation of coefficient k_g have shown that, for the given initial velocity of micrometeoroids, the values of this coefficient depend on deflection of its direction from the direction to the Earth center. It is shown that for low-altitude orbits the flux density can increase up to 60%. The distribution of probabilities of various directions of particles flying to spacecraft structural elements is found to be non-uniform.