Voyager 1 and Voyager 2 launched in 1977 and made a grand tour of the solar system's outer planets. They are the only functioning spacecraft in interstellar space, and they are still sending back measurements of the interstellar medium.
NASA's Hubble celebrates decade of tracking outer planets
NASA's Hubble celebrates decade of tracking outer planets - EurekAlert
NASA’s Hubble Celebrates Decade of Tracking Outer Planets
