Voyager 2: Aug. 20, 1977 - 14:29:00 UTC

NASA’s Voyager 1 and 2 were designed to take advantage of a rare planetary alignment to explore the outer solar system. Voyager 2 targeted Jupiter, Saturn, Uranus and Neptune before joining its sister probe on an interstellar mission. Voyager 2 is the only spacecraft to study all four of the solar system's giant planets at close range