Lunar gravitational capture conditions

Certain classes of lunar trajectories allow spacecraft to approach the moon from outside its sphere of influence and to end up in a temporarily captured state around the moon without any thrusting necessary. The spacecraft's state at the moon associated with these efficient types of capture is investigated. First, analysis is done on objects approaching the moon from a direction that results in the lowest eccentricity at perilune. Following that, analysis is done on objects approaching the moon with trajectories that originate from the Earth. This second set of orbits are ballistic capture transfer trajectories that allow spacecraft to go from low Earth orbit to lunar capture with only one engine burn at Earth. The properties investigated provide insight to this particular form of transfer and can help in mission design.