Single Injection Earth Return Trajectory Options for Small Spacecraft Missions to the Moon

Single Injection Earth Return Trajectory Options for Small Spacecraft Missions to the Moon

There exist several classes of high energy trajectories that are injected from Earth centered orbits to deep space destinations and return to the vicinity of the Earth sometime later due to the direct influence of a third body perturbation. These trajectories can be designed to flyby the moon or near Earth asteroids and comets. The appealing characteristic of these trajectories is that they require a single injection maneuver at the Earth and no further translational control thereafter. A spacecraft on such a trajectory can take observations and measurements of the flyby body and download the data once it returns to the vicinity of the Earth. The return trajectory could place the spacecraft into a direct reentry path through the Earth's atmosphere or an elliptical or hyperbolic Earth flyby that will be completely passive since no maneuvers are made. This type of trajectory is applicable to passive spacecraft missions such as student built micro satellites that have no on board propulsion for attitude or translational control. Issues addressed are the dispersions in the return trajectory due to errors in the injection maneuver and other orbit parameters. The characteristics of an Earth return lunar flyby mission for small satellites are discussed.