The Depths of Space: A New Book About the Pioneer Planetary Probes

All were simple yet amazingly successful trailblazers, and two are carrying a controversial message to the stars. Author Mark Wolverton talks about his new book tracing the history of the Pioneer series of spacecraft. Emily wonders about the disappearing Martian atmosphere in the reprise of a Q&A segment, space exploration headlines, and Bruce Betts is on location at the zoo for this week's What's Up segment, including a new trivia contest.