NASA's Voyager 1 and 2, launched in 1977 to explore Jupiter, Saturn and other planets, are now in interstellar space beyond Sun's heliosphere. Voyager 1, launched on September 5, 1977, is about 25.3 billion km away, while Voyager 2, launched on August 20, 1977, is 21.1 billion km away. Voyager 1 lies in Ophiuchus, while Voyager 2 is in Pavo.