Construction of a Three-Pulse Approach to Phobos Trajectories with Access to the Mars Hill Sphere Based on the Solution of a Series of Lambert's Problems

The optimization problem of the expedition to Phobos with returning to the Earth in a pulse setting is considered. The trajectory is assumed to be a combination of a series of Lambert's problems solutions. The problem was solved numerically with taking into account the ephemeris. The gain of three-pulse approach to Phobos in comparison with the direct flight scheme was estimated.