Several robotic spacecraft have used the "gravity assist" technique to achieve their targets "high up" in the Sun's gravity well. Voyager 2 launched in August 1977 and flew by Jupiter for reconnaissance, and for a trajectory boost to Saturn.
To get the best gravity effect or slingshot it is vital to launch the space craft at the right time so that it gets the slingshot effect in the right direction, hurling it towards its destination rather than whipping it out away from the Solar System into deep space.
