Voyager 1 was NASA’s first spacecraft to reach interstellar space.
Launched on September 5, 1977, Voyager 1 conducted close flybys of Jupiter and Saturn before beginning its journey outward from the Solar System. Its trajectory was shaped by gravity assists, including a close encounter with Saturn’s moon Titan.
NASA announced in 2013 that Voyager 1 had crossed the heliopause, the boundary where the solar wind gives way to interstellar plasma. It was the first human-made object confirmed to enter interstellar space, although it remains gravitationally bound to the Milky Way.
Voyager 2 launched first, on August 20, 1977, but followed a different path and crossed the heliopause in 2018. The two spacecraft carry identical Golden Records containing sounds and images intended as messages from Earth.