Classification of Out-of-Plane Swing-By Trajectories

Abstract

The swing-by maneuver uses a close approach with a celestial body to modify the velocity, energy, and angular momentum of a spacecraft. The literature has several papers studying this problem, usually using a patchedconic approximation. In the present paper the swing-by maneuvers are studied and classiŽ ed under the model given by the three-dimensional restricted three-body problem. To show the results, the orbits of the spacecraft are classiŽ ed in four groups: elliptic direct, elliptic retrograde, hyperbolic direct, and hyperbolic retrograde. Then the modiŽ cation in the orbit of the spacecraft caused by the close approach is shown in plots that specify from which group of orbits the spacecraft is coming and to which group it is going. Several families of orbits are found and shown in detail. The effect of every parameter involved in this problem is studied individually. The results generated here have a potential use to solve optimal problems, such as Ž nding trajectories that satisfy some given constraints (such as achieving an escape or capture) with some parameters being extremized (position, velocity, etc.). Two optimal problems are solved in this paper to show this application.