Nothing touched by a human has ever traveled this far. Voyager 1 was launched in 1977 to study Jupiter and Saturn close up, and it kept on going and going, taking the first close pictures of Uranus and Neptune and becoming the first object from Earth to leave the solar system. It currently sits about 20,000,000 kilometers from us and is speeding away at 17 kilometers a second through empty space. Voyager isn’t doing much now, just conserving its batteries and keeping its systems in standby. They’re expected to last until 2025 or so.
Voyager 1 sent back full-color digital images using a camera under 1 megapixel, with a super-slow data transfer rate and a computer that’s less powerful than the average calculator. In case other civilizations come in contact with it, it carries a record (you know, like vinyl, but in this case it’s made of metal) and instructions on how to build a record player. Yet, in the 35 years since its launch, we don’t really have a better, more reliable way to build a spacecraft. Sure, we could build one with a better camera or one with faster transmission, but in terms of sheer ability to survive, Voyager 1 trumps them all.
Science fiction stories have talked of the day when we follow Voyager out to the stars, but so far we’ve yet to set foot on even our closest planetary neighbor. For better or worse, Voyager 1 will be alone out there for a long, long time.