The NASA Innovative Advanced Concepts program gathers its “fellows” each year to share what they’ve learned about some of the most fascinating science and engineering imaginable. Mat Kaplan visits with Program Executive Jason Derleth and seven leaders of funded studies.&nbsp;Astronaut Mae Jemison also attended and returns to Planetary Radio. Cosmonaut Alexei Leonov passed away last week at 85. He is remembered and praised by space historian John Logsdon.&nbsp;All this, headlines from <a href="http://planetary.org/downlink" target="_blank">The Downlink</a>, and Bruce Betts! Learn more about this week’s guests and topics at: &nbsp;<a href="http://www.planetary.org/multimedia/planetary-radio/show/2019/1016-2019-niac-symposium-leonov.html" target="_blank">http://www.planetary.org/multimedia/planetary-radio/show/2019/1016-2019-niac-symposium-leonov.html</a>See <a href="https://omnystudio.com/listener">omnystudio.com/listener</a> for privacy information.See <a href="https://omnystudio.com/listener">omnystudio.com/listener</a> for privacy information.

How Long Was Mars Wet?

Planetary Radio brings you the human adventure across our Solar System and beyond. We visit each week with the scientists, engineers, leaders, advocates, and astronauts who are taking us across the final frontier. Regular features raise your space IQ while they put a smile on your face. Join host Sarah Al-Ahmed and Planetary Society colleagues including Bill Nye the Science Guy and Bruce Betts as they dive deep into space science and exploration. The monthly Space Policy Edition takes you inside the DC beltway where the future of the US space program hangs in the balance. Visit planetary.org/radio for an episode guide and much more.