It’s the Grandest Finale. The spectacular Cassini mission’s exploration of Saturn will end on September 15th when the spacecraft plunges into the planet. Cassini Project Scientist Linda Spilker is back with one last mission update. Mat also announces a live Cassini celebration on the evening of September 18, 2017. Bruce Betts and Mat Kaplan are back from the Great American Eclipse’s path of totality with another What’s Up segment and a new space trivia contest that features the eclipse.