This is one in a series of whimsical retro posters designed to celebrate Cassinis Grand Finale after almost 20 years in space. NASA Presents: Cassinis Finale Saturn Sept 15 2017 End of Mission: 5:04 a.m. PDT The symbols show on the poster represent the four planets visited by Cassini (from left to right): Earth, Venus, Jupiter and Saturn. Credit: NASAJet Propulsion LaboratoryCaltech