... Ballistics, navigation and flight control of the spacecraft, going to the L2 point of Sun-Earth system. ... and calculation algorithms have been developed: - an algorithm, building nominal trajectories for one impulse flights to the L2 point of Sun- Earth system, including a Moon swingby maneuver or not. - an algorithm, calculating corrections of spacecraft trajectory needed for the flight from Earth to halo orbit and for stationkeeping of the spacecraft moving in halo ...