Both Voyager probes feature three sets, or branches, of thrusters: two sets of attitude propulsion thrusters and one set of trajectory correction maneuver thrusters. During the mission’s planetary flybys, both types of thrusters were used for different purposes. But as Voyager 1 travels on an unchanging path out of the solar system, its thruster needs are simpler, and either thruster branch can be used to point the spacecraft at Earth.