Saturn is between 1.2 billion kilometers (0.0001268 light years) and 1.67 billion kilometers (0.0001765) from Earth, depending on where both planets are in their orbits, according to Universe Today. Earth and Saturn are farthest from each other when on opposite sides of the Sun.
Saturn is the farthest planet from the Earth that can still be seen by the human eye unaided, explains Space.Com. Pioneer 11, the first spacecraft sent to look at Saturn, took more than six years to get there. Launched a little over four years after Pioneer 11, Voyager 1 managed to make the trip in about three years, passing Saturn in November 1980. With a much quicker trip, this was only about one year after the previous Pioneer fly-by, and was only possible due to Voyager's taking advantage of a very rare, favorable gravitational alignment of the planets in order to do it.