As The Atlantic explains:

In August of 1977, the first of two identical robotic probes was launched from Cape Canaveral, Florida, bound for our outermost planets and beyond. Voyager 1 and Voyager 2 have each traveled more than 10 billion miles in the past 40 years, sending back invaluable observations and images.

You might be interested in The Best Sites For Learning About Voyager 1 & Its Departure From Our Solar System.