It’s been 40 years to the day since the Voyager mission commenced with the launch of Voyager 1 on September 5, 1977, with its twin Voyager 2 launching two weeks later. This groundbreaking and incredibly ambitious mission touched on practically every aspect of our solar system and planetary neighbors.
Here are 20 of the most important images and bits of science sent back by the pioneering spacecraft. As a rule, the images are from NASA/JPL, but they were collected from numerous sources, including Wikimedia Commons (where some high-resolution files are hosted) and the Space Science Data Coordinated Archive. If you want to learn more, NASA and JPL have you covered.