Voyager 1

Launched in 1977, Voyager 1 flew past Jupiter and Saturn, discovered active volcanoes on Io, and took the iconic "Pale Blue Dot" photo from 6 billion kilometers away. In 2012, it became the first human-made object to enter interstellar space. Nearly 50 years later, it's still transmitting data from over 24 billion kilometers away — the most distant human-made object in existence. It carries a Golden Record with sounds and images of Earth, just in case someone out there is listening.