Study of aerogravity assist transfer trajectory and application in interplanetary exploration missions

In interplanetary exploration missions, the gravity assist is an available approach for reducing launch energy and total velocity increments. The gravity assist technique is limited, however, by the turn angle of hyperbolic excess velocity vector that can be affected by a flyby body. This turn angle depends on the size and mass of the planet and so on. One method of circumventing this turn angle limitation is to use aerogravity assist (AGA). In this paper, we analyzed the AGA transfer trajectory and presented the patching condition for designing the AGA transfer trajectory. This patching condition is the basic principle for designing and analyzing AGA trajectory. Then, taking the exploring Ivar asteroid as an example, an approach of designing AGA transfer trajectory with plotting contour map and patching conic was presented, and the trajectory parameters for exploring Ivar asteroid were presented. The calculation demonstrates that AGA technique not only decreases the launch energy and total velocity increments but also finds more exploring opportunities.