Planetary Radio: Space Exploration, Astronomy and Science

Artemis II is the first crewed lunar mission since Apollo 17, and riding alongside the crew is one of the most ambitious biology experiments ever sent to space. It's called AVATAR, short for A Virtual Astronaut Tissue Analog Response: tiny organ chips grown from the astronauts' own cells, flying the same trajectory around the Moon, exposed to the same deep-space radiation and microgravity as the crew themselves. Lisa Carnell, director of NASA's Biological and Physical Sciences Division, explains what this experiment could mean for the future of human exploration.
Then, Alain Maury, asteroid hunter and Planetary Society Shoemaker Near-Earth Object grant recipient, tells the story of how his MAPS survey in Chile's Atacama Desert spotted a faint, fuzzy object that turned out to be something extraordinary. C/2026 A1 (MAPS) is a sungrazing comet now falling toward the Sun on a path that will bring it within 162,000 kilometers (100,000 miles) of the solar surface on April 4th. If it survives that encounter, it could become one of the most spectacular comets in decades.
And finally, Planetary Society Chief Scientist Bruce Betts joins us for What's Up, including how to spot the comet yourself, if it makes it through.
Discover more at: https://www.planetary.org/planetary-radio/2026-avatar-and-sungrazer
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Artemis II is about more than getting four humans to the Moon and back. It's an opportunity to gather data on human health in deep space that we haven’t had in over 50 years.
This week, we’re joined by Steve Platts, chief scientist of NASA's Human Research Program, who walks us through the suite of human health experiments flying aboard Artemis II, from the ARCHER wearable sensors tracking crew health and team dynamics, to dry saliva swabs measuring stress hormones. Then Casey Dreier, chief of space policy at The Planetary Society, helps us make sense of NASA's Ignition Day, a major press event held on March 24 in which the agency unveiled sweeping changes to its lunar exploration plans and beyond.
And we close with Bruce Betts, chief scientist of The Planetary Society, in our weekly What's Up, where we explore one of the stranger phenomena in human spaceflight, the flashes of light astronauts sometimes see when cosmic rays pass through their eyes.
Discover more at: https://www.planetary.org/planetary-radio/2026-astronaut-health-experiments-artemis-ii
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Join us for an awe-inspiring conversation with astrobiologist and astronomer Caleb Scharf as he eloquently makes the case for "dispersal," the nearly inevitable advance of life and humanity across our solar neighborhood. From the book: "The idea of Dispersal is one where the sheer scale and scope of life’s future extension into the solar system profoundly changes things: not because of some new (and unlikely) cultural enlightenment from within but because of what the enormous expanse of space will do to dilute and change our species and all others.” Adam Frank says of the book, “If we can make it through the many crises of the next century, then the Solar System and the stars beyond await us. In The Giant Leap, Caleb Scharf demonstrates how becoming a true space-faring species is more than just humanity’s future.”
Discover more at: https://www.planetary.org/planetary-radio/book-club-caleb-scharf
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Humanity is going back to the Moon, and Europe is already playing a critical role in making it happen. This week, Planetary Radio brings you voices straight from the 18th European Space Conference in Brussels, Belgium, where more than 2,000 of the world’s top space leaders gathered to shape the future of European space exploration.
We begin with conference co-organizer Tomas Dimitrov of Logos and Business Bridge Europe, who sets the stage for the conversations ahead. From there, we hear from European Commissioner for Defence and Space Andrius Kubilius, ESA Director General Josef Aschbacher, French Minister Delegate for European Affairs Benjamin Haddad, and Germany’s Federal Space Minister Dorothee Bär.
We also take you inside the Moonlight Initiative panel, bringing you the full conversation as scientists and engineers from ESA, NASA, and industry lay out their vision for building GPS and communications infrastructure around the Moon, and wrestle with what it will really take to support a permanent human presence there.
Then, Planetary Society Chief Scientist Bruce Betts joins us for What’s Up to tackle one of the most fascinating and unexpected challenges of lunar exploration: what time is it on the Moon?
Discover more at: https://www.planetary.org/planetary-radio/2026-european-space-conference
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Gentry Lee spent nearly five decades at NASA's Jet Propulsion Laboratory, and in that time he helped shape some of the most ambitious missions in the history of space exploration. A new documentary, “Starman,” chronicles his career and the big question that runs through it: is there life beyond Earth? Lee worked on every NASA mission to land on Mars, helped Carl Sagan bring the Universe to living rooms around the world with “Cosmos,” and oversaw dozens of active missions as Chief Engineer for the Solar System Exploration Directorate at JPL. Few people have had a front-row seat to the Space Age quite like him.
In this episode, host Sarah Al-Ahmed sits down with Gentry at Planetary Society headquarters just one day after his retirement from JPL. He reflects on the colleagues who shaped him, the missions that changed our understanding of the Solar System, and why the search for life beyond Earth remains the most profound endeavor humanity has ever undertaken.
Discover more at: https://www.planetary.org/planetary-radio/2026-starman
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