On this day 35 years ago.
Voyager 1 was launched. About the size of a small car it carries some cameras and scientific instruments. It has been for some years the most distant man made object from the Earth (Currently it is more than eleven billion miles distant from the Sun and receding rapidly). It may already be the first man made object to leave the Solar System.
Before leaving it did the Grand Tour of the known planets and sent back pictures of Jupiter’s Red Spot, erupting volcanoes on Io, traces of water under the ice of Europa and methane rain on Titan, all unexpected discoveries.
It flies on, with sufficient fuel for instruments and communications until at least 2020, it is, of course, nuclear powered.