It's the end of an era in space exploration: the Cassini-Huygens spacecraft's 20-year mission to Saturn is about to end with a bang — and a ball of fire. You may not know that some of Saturn's moons are very Earth-like, and Cassini even discovered that one moon might have the building blocks of life. Tomorrow we'll say goodbye to the spacecraft as it ends its mission by intentionally burning up in Saturn's atmosphere. We are joined by Morgan Cable, a technologist at NASA and member of the Cassini team, Sarah Hörst, assistant professor of planetary science at Johns Hopkins, Michelle Thaller, an astronomer and deputy director for science communications at NASA's Goddard Space Flight Center and Nadia Drake, a contributing writer at National Geographic.