Designing of the “Spectr-RG” spacecraft's orbit with the guaranteed radio visibility from Russian tracking stations

This work covers polytypic quasiperiodic orbits’ ballistic design for the Sun-Earth system $L_2$ libration point. M.L. Lidov's isoline building method providing one-impulse transfers from LEO to a quasi periodic orbit in the vicinity of the collinear libration point has been used for the “Spectr RG's” required orbit forming with the daily radio visibility from Russian ground tracking stations. The results of numerical calculations for real windows of the “Spectr RG” project with the daily radio visibility are presented. This will significantly improve the reliability of the spacecraft's control.