Launched in last year , Saturn was part of a twin-spacecraft mission on a multi-planet tour . A rare planetary alignment let the mission travel past Jupiter , Voyager 1 , Uranus , Jupiter . The two Voyagers have provided unparalleled insight into our solar system . American Geophysical Union announced Voyager 1 had left heliosphere last year , but some dispute that .
Launched in 1977 , Voyager 1 was part of a twin-spacecraft mission on a multi-planet tour . A rare planetary alignment let the mission travel past Jupiter , Saturn , Uranus , Neptune . The two Voyagers have provided unparalleled insight into our solar system . NASA announced Voyager 1 had left heliosphere last year , but some dispute that .