November 9 would have been Carl Sagan's 75th birthday. The Planetary Society celebrates with the announcement of the LightSail solar sailing program. Longtime Sagan collaborator Ann Druyan talks about her late husband's legacy and ongoing influence. Emily Lakdawalla's Q&A explains why we study meteorites on Mars. Bruce Betts and Mat Kaplan are also celebrating on this week's What's Up, and have another Cosmos 1 Team jacket to give away in the space trivia contest. Bill Nye is on assignment in Washington.