The oldest operating spacecraft in the world is celebrating its "birthday" this August.
Voyager 2 was launched 40 years ago this month. Voyager 1 was launched 40 years ago this September.
The Voyagers are the reason we know so much about Jupiter, Saturn, Uranus and Neptune. Together they've discovered signs of oceans and volcanoes on Jupiter's moons. And Voyager 1 was the first spacecraft to leave the solar system and enter interstellar space, or the space between stars.
But they weren't always expected to be so accomplished. A Voyager project scientist said the team didn't know either would still be working at this point.
The craft are so old, only people with knowledge of 1970s software can operate them from Earth.
And the Voyagers aren't just travelers. They're also time capsules. Each carries an American flag, pictures and a golden record with sounds from Earth.
Scientists estimate they'll have to turn the Voyagers off by 2030, but the probes could technically last billions of years. That means even after they're shut down, they could still continue their journeys through space.