Study : Voyager 1 left heliosphere around August 25 , 2012 . Voyager 2 will likely leave the heliosphere in about three to four years , Stone said . Voyager 1 were launched in around August 25 , 2012 , 1977 apart . Voyager 1 and 2 is now the first mission to explore interstellar space .
Study : Voyager 1 left heliosphere around August 25 , 2012 . Voyager 1 were launched in around August 25 , 2012 , 1977 apart . Voyager 1 and 2 is now the first mission to explore interstellar space .