Propulsion Systems
Spacecraft Trajectory
The Voyager 1 and Voyager 2 trajectories are illustrated on Fig.1. Slingshot trajectory significantly reduces the required amount of energy but also increases the traveling time since the spacecraft trajectory has to travel from one planet to another one. Besides, it is important to mention the slingshot acceleration cannot be greater than twice the speed of the planet.
Fig.1: Simplified slingshot mechanism
Actually, the extra distant traveled as well as the low speed increase (about 20 km. s-1 for every gravitational slingshot in the solar system) makes this technique very time-inefficient for this interstellar travel.
Fig.2 : Voyager 1 and Voyager 2 trajectories
From then on, we privilege a straight trajectory continuously assisted with a propulsion system in the solar system.