The Voyager probes were launched about two weeks apart in 1977. Voyager 2 was initially supposed to make a four-year sojourn to Saturn, but 33 years later it is still beaming back data from the far reaches of the solar system. Data, but no alien transmissions, at least not yet. But just in case it does run into someone out there, Voyager 2 carries a disk with greetings in more than 50 languages.