The Mars Exploration Rover science team has conclusively announced that there was once water, and lots of it, on Mars' Meridiani Planum. Our guest this week helped make this momentous discovery. Ben Clark's experience on the Red Planet goes back at least to the Viking missions in the seventies. He's Lockheed Martin's Chief Scientist of Space Exploration. Bruce Betts also makes a noisier than usual visit with the latest What's Up!, and a new planetary trivia contest.