How do you keep a dazzlingly complex spacecraft in good health after 20 years in space? That’s the challenge for Julie Webster and her team of engineers supporting the Cassini mission at Saturn. Jason Davis reports on the possible discovery of the asteroid impact that wiped out most of Earth’s life. Bill Nye the Science Guy is following the youthful wanderings of Jupiter. Cassini is the source of this week’s space trivia contest on What’s Up.