Voyager outside the solar system, illustration. From left to right are: the Sun, its planets, the Voyager spacecraft leaving the heliosphere and the Oort Cloud. The heliosphere is a protective bubble around the Sun, separating the planets from interstellar space. It has a turbulent outer boundary known as the heliosheath. Voyager 1 and Voyager 2 (both launched in 1977) crossed the heliosheath thus passing into interstellar space in August 2012 and November 2018 respectively. They will take around 300 years to reach the inner edge of the Oort Cloud (cloud of icy objects, right) and could take 30,000 years to fly past it.