Planetary Radio: Space Exploration, Astronomy and Science

Four astronauts — Commander Reid Wiseman, Pilot Victor Glover, Mission Specialists Christina Koch and Jeremy Hansen — are on their way around the Moon, on a journey that will take them farther from Earth than any human has gone before. This week on Planetary Radio, we bring you the sounds of launch day and the voices of the people who lived it. You’ll hear from the engineers who built the spacecraft, including Mark Tobias, chief engineer at Northrop Grumman, Jan-Henrik Horstmann, European Service Module team leader at ESA, and Debbie Korth, deputy manager of NASA's Orion Program. U.S. Representative Mike Haridopolos and Senator and former astronaut Mark Kelly share their perspectives from the ground. Canadian Space Agency astronaut Joshua Kutryk reflects on what it means for Canada to have one of their own heading to deep space for the very first time. NASA Chief Exploration Scientist Jake Bleacher and Lisa Carnell, director of Biological and Physical Sciences at NASA's Science Mission Directorate, break down some of the research happening on this mission. NASA astronaut Steve Bowen shares what it feels like to watch a crew launch knowing exactly what they're about to experience. And Joel Kearns, NASA's deputy associate administrator for exploration, reflects on what this moment means for the future of human spaceflight. Plus, Planetary Society Science Editor Asa Stahl and Digital Community Manager Ambre Rose Trujillo, share what it was actually like to be there on launch day. And Planetary Society Chief Scientist Bruce Betts joins us for What's Up, with a look at what we've learned about the Moon since the Apollo era. Discover more at: https://www.planetary.org/planetary-radio/2026-artemis-ii-launch See omnystudio.com/listener for privacy information.

What makes Cape Canaveral the center of U.S. spaceflight? The answer is a fascinating mix of geography, military strategy, Cold War politics, and a fair amount of historical accident. In this episode of the Space Policy Edition of Planetary Radio, host Casey Dreier, chief of space policy at The Planetary Society, sits down with Stephen C. Smith, author and writer behind the Substack The Space Pundit, to discuss his book Return to Launch: Florida and America's Space Industry. A longtime Kennedy Space Center Visitor Complex communicator and Merritt Island resident, Smith brings a unique perspective to the story of how a remote Florida peninsula became the gateway to the Cosmos. The conversation spans the full arc of Cape Canaveral's history, from captured Nazi V-2 rockets fired off a concrete slab in 1950, the Apollo era's dramatic economic boom and bust, and the rise of commercial spaceflight. Along the way, Smith and Dreier explore why Mexico's president inadvertently shaped U.S. launch site selection, how eminent domain built a spaceport, and what Space Florida did to help break the region's cycle of economic dependence on government programs. See omnystudio.com/listener for privacy information.

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 See omnystudio.com/listener for privacy information.

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 See omnystudio.com/listener for privacy information.

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 See omnystudio.com/listener for privacy information.

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 See omnystudio.com/listener for privacy information.

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 See omnystudio.com/listener for privacy information.

Is the United States really in a new space race with China? Or is that framing missing the bigger picture? In this Space Policy Edition of Planetary Radio, Casey Dreier, chief of space policy at The Planetary Society, sits down with Patrick Besha, former NASA strategic advisor on China, to explore the realities behind China’s rapidly advancing space program. They discuss how China’s political system shapes its long-term space strategy, why the rhetoric about a “space race” may be misleading, and how competition between the United States and China in space is likely to unfold over the coming decades. Discover more at: https://www.planetary.org/planetary-radio/spe-us-china-space-race See omnystudio.com/listener for privacy information.

NASA has announced a major restructuring of the Artemis program, reshaping the roadmap for returning humans to the Moon. At a February 27 press conference, agency leadership addressed the rollback of Artemis II following post–wet–dress–rehearsal testing and unveiled significant changes to upcoming missions, including shifting Artemis III from a planned lunar landing to a low-Earth-orbit rendezvous and integrated systems test. In this episode, you’ll hear remarks from NASA Administrator Jared Isaacman and Lori Glaze, Moon to Mars program manager and acting associate administrator for NASA’s Exploration Systems Development Mission Directorate. They explain what happened with Artemis II and why NASA is changing course. Then, host Sarah Al-Ahmed is joined by Jack Kiraly, director of government relations at The Planetary Society, and Ari Koeppel, AAAS science and technology policy fellow, to unpack the political and strategic forces behind this shift and what it means for the future of lunar exploration. In What’s Up, Bruce Betts, our chief scientist, looks back at Apollo 9, the Earth-orbiting mission that proved the Lunar Module could operate independently before NASA attempted a lunar landing. Discover more at: https://www.planetary.org/planetary-radio/2026-artemis-update See omnystudio.com/listener for privacy information.

Could a single ancient impact have briefly transformed one of the Solar System’s darkest moons into a cryovolcanic world? When Voyager 2 flew past Uranus in 1986, it captured the only close-up images we have of Umbriel, a heavily cratered, charcoal-dark satellite long considered geologically inactive. But one feature stands out: a bright ring inside the 131-kilometer-wide Wunda crater. In this episode, Sarah Al-Ahmed speaks with Adeene Denton, NASA postdoctoral program fellow at the Southwest Research Institute, about her team’s new study published in the Journal of Geophysical Research: Planets. Using shock physics simulations, Denton and her colleagues reconstruct the impact that formed Wunda crater to determine what Umbriel’s interior must have been like at the time. Their modeling explores whether impact-induced cryovolcanism can explain the bright deposits observed on the crater floor. Then, in What’s Up, Bruce Betts, chief scientist of The Planetary Society, joins Sarah to break down one of the key mechanisms that keeps icy moons from freezing solid, tidal heating driven by orbital resonance. Discover more at: https://www.planetary.org/planetary-radio/2026-cryovolcanism-on-umbriel See omnystudio.com/listener for privacy information.

They informed and entertained together throughout the first 20 years of Planetary Radio. Listen in as the Society’s chief scientist and book club edition host Mat Kaplan share the mic once again for a delightful conversation about Dr. Betts’ two new space books for young people. “Are We Alone?” introduces the search for life across the Universe, while “The Size of Space” collects many of Bruce’s brilliant and hilarious ways to cut our Solar System down to human size. Discover more at: https://www.planetary.org/planetary-radio/book-club-bruce-betts See omnystudio.com/listener for privacy information.

This week on Planetary Radio, we mark a major leadership transition at The Planetary Society. Host Sarah Al-Ahmed sits down with Bill Nye, outgoing chief executive officer and newly appointed chief ambassador of The Planetary Society, and Jennifer Vaughn, incoming chief executive officer and former chief operating officer, for a candid conversation about this long-planned transition. Together, Bill and Jenn reflect on how the organization, under their shared leadership, grew into the world’s largest and most effective nonprofit dedicated to advancing the scientific exploration of space. Then, Bruce Betts, chief scientist of The Planetary Society, joins Sarah for What’s Up. They discuss an upcoming planetary alignment on and around February 28, 2026. Discover more at: https://www.planetary.org/planetary-radio/2026-jennifer-vaughn-ceo See omnystudio.com/listener for privacy information.

Where did Earth’s water come from? In this episode of Planetary Radio, we explore how scientists are answering that question by studying a remarkably well-preserved record of the early Solar System: lunar samples brought back by the Apollo missions. Host Sarah Al-Ahmed is joined by Tony Gargano, postdoctoral fellow at the Lunar and Planetary Institute with the University Space Research Association and a research affiliate at NASA’s Johnson Space Center. Gargano studies lunar rocks and regolith to understand how planets form, evolve, and acquire key ingredients like water over time. By analyzing subtle chemical fingerprints preserved in Apollo-era lunar regolith, his work helps constrain how much water meteorites could have brought to Earth and what that means for our planet’s path to habitability. The episode also features a short bonus segment with actor George Takei, recorded at the Academy Museum of Motion Pictures during a screening of “Star Trek IV: The Voyage Home.” Takei reflects on the enduring legacy of “Star Trek,” its influence on generations of scientists and explorers, and why he is excited about humanity’s return to the Moon in the Artemis era. He connects science fiction’s hopeful vision of the future with the real science helping us understand our origins today. Discover more at: https://www.planetary.org/planetary-radio/2026-earth-water-apollo-moon-dust See omnystudio.com/listener for privacy information.

What does a NASA authorization bill actually do, and why does it matter? In this episode of Space Policy Edition, we dig into one of the most misunderstood but powerful tools Congress uses to shape the future of U.S. space exploration. Host Casey Dreier, chief of space policy at The Planetary Society, is joined by Jack Kiraly, the Society’s director of government relations, for a deep dive into how NASA authorization bills work, how they differ from appropriations, and why they can have decades-long consequences for science missions, human spaceflight, and planetary defense. The discussion also reflects on a major recent win for space advocates: Congress’s bipartisan decision to protect NASA science funding. Discover more at: https://www.planetary.org/planetary-radio/spe-what-is-a-nasa-authorization-bill See omnystudio.com/listener for privacy information.

What if Europa’s seafloor isn’t alive with activity after all? This week on Planetary Radio, host and producer Sarah Al-Ahmed explores new research that reframes how scientists think about one of the Solar System’s most intriguing ocean worlds. Sarah is joined by Paul Byrne, associate professor of earth, environmental, and planetary sciences at Washington University in St. Louis. Paul is the lead author of a new study suggesting that the seafloor beneath Europa’s global ocean may be geologically quiet today, potentially lacking the hydrothermal activity often associated with habitable environments on Earth. Together, they discuss how scientists investigate places we can’t yet observe directly and why Europa remains a compelling world to explore regardless of what we find. Then, Bruce Betts, chief scientist of The Planetary Society, joins us for What’s Up to explain why Saturn’s moon Enceladus shows strong evidence for active hydrothermal vents beneath its icy crust, offering a fascinating contrast between two ocean worlds. Discover more at: https://www.planetary.org/planetary-radio/2026-europas-quiet-seafloor See omnystudio.com/listener for privacy information.

Humans are preparing to return to the Moon. On this episode of Planetary Radio, host Sarah Al-Ahmed is joined by Kelsey Young and Noah Petro, two of the scientists helping turn humanity’s return to the Moon into reality. Kelsey Young is a research space scientist at NASA Goddard Space Flight Center and serves as the Artemis Science Flight Operations Lead. She also leads the Lunar Observations and Imaging Campaign for Artemis II, defining what astronauts will observe, document, and study as they fly around the Moon for the first time in more than 50 years. Noah Petro is the lab chief of the Planetary Geology, Geophysics, and Geochemistry Laboratory at NASA Goddard and the Project Scientist for the Lunar Reconnaissance Orbiter. He also serves as the Project Scientist for Artemis III, helping shape the science behind humanity’s first lunar footsteps of the 21st century. Together, they discuss how Artemis II and Artemis III build on decades of lunar science, how astronauts are being trained to observe the Moon like geologists, and why the Moon’s south pole is such a compelling destination for future exploration. Then, we wrap up with What’s Up, where Bruce Betts, chief scientist of The Planetary Society, shares the story of the first and so far only professional geologist to walk on the Moon. Discover more at: https://www.planetary.org/planetary-radio/2026-artemis-ii-and-iii See omnystudio.com/listener for privacy information.

After months of uncertainty, NASA science has been spared from the largest proposed budget cuts in the agency’s history. In this episode of Planetary Radio, host Sarah Al-Ahmed unpacks how Congress moved to restore near-full funding for NASA science and what that victory really means for missions, researchers, and the future of space exploration. Sarah is joined by Jack Kiraly, director of government relations at The Planetary Society, and Ari Koeppel, an AAAS science & technology policy fellow at The Planetary Society, to break down what passed in the FY 2026 budget, why the details matter, and how bipartisan support helped protect science programs across planetary science, astrophysics, Earth science, and heliophysics. The conversation also takes an honest look at the costs of the past year, from lost jobs and disrupted missions to shaken morale, and why rebuilding NASA’s scientific workforce will take time, even after this hard-won win. We also look ahead to what comes next as the FY 2027 budget process begins, and why sustained public engagement remains essential to protecting space science. Plus, Bruce Betts, chief scientist of The Planetary Society, joins us for What’s Up, where we discuss the recent early return of astronauts from the International Space Station, what’s known about the situation, and what it means for station operations. Discover more at: https://www.planetary.org/planetary-radio/2026-nasa-science-saved See omnystudio.com/listener for privacy information.

Famed astrophysicist and science communicator Adam Frank shares his sense of wonder and humor in a live conversation about his excellent new book, “The Little Book of Aliens.” Join Adam and host Mat Kaplan as they explore the origin of life, the search for extraterrestrial intelligence, and whether all those UFO sightings are worthy of deeper investigation. Discover more at: https://www.planetary.org/planetary-radio/book-club-adam-frank See omnystudio.com/listener for privacy information.

Our Solar System is wrapped in a vast, invisible bubble created by the Sun, a protective region that shields Earth and the planets from much of the radiation that fills our galaxy. But until recently, scientists have only had rough sketches of what this boundary looks like and how it behaves. In this episode of Planetary Radio, host Sarah Al-Ahmed is joined by David McComas, professor of astrophysical sciences at Princeton University and principal investigator of NASA’s Interstellar Mapping and Acceleration Probe (IMAP) and Interstellar Boundary Explorer (IBEX) missions, along with Matina Gkioulidou, a heliophysicist at Johns Hopkins Applied Physics Laboratory, former IMAP-Ultra instrument lead, and current IMAP project scientist and co-investigator. Now stationed at the Sun–Earth L1 Lagrange point, IMAP uses 10 instruments to study the heliosphere — the region where the solar wind collides with material from interstellar space. The mission does this by tracking energetic neutral atoms, particles that travel in straight lines from distant regions of the heliosphere, allowing scientists to map areas of space that spacecraft can’t directly sample. McComas and Gkioulidou explain how IMAP builds on the legacy of Interstellar Boundary Explorer, what makes this mission different, and why understanding the Sun’s influence across space matters not just for fundamental science, but for space-weather forecasting and protecting technology and astronauts closer to home. Discover more at: https://www.planetary.org/planetary-radio/2026-imap See omnystudio.com/listener for privacy information.

What does it really mean to enter interstellar space, and what have we learned since humanity first crossed the invisible boundary between our Sun and the stars? In this episode of Planetary Radio, we explore the science of the heliosphere and the realm beyond with Linda Spilker, project scientist for the Voyager mission at NASA Jet Propulsion Laboratory. Drawing on decades of experience with the twin spacecraft, Spilker shares how Voyager reshaped our view of the Solar System’s outer frontier, from the nature of the heliopause to the unexpectedly rich structure of the local interstellar medium. We unpack what Voyager 1 and Voyager 2 have taught us about charged particles, magnetic fields, and cosmic rays beyond the Sun’s protective bubble, and why those measurements have upended earlier ideas about where the Solar System truly ends. Spilker also reflects on the mission’s extraordinary longevity, the ingenuity required to keep the spacecraft communicating across the vastness of space, and what Voyager’s legacy means for future journeys between the stars. Then, in What’s Up, Bruce Betts, chief scientist at The Planetary Society, places Voyager in context, showing how long-lived missions shape the bigger picture of space science and why observing longer can lead to some of our most profound discoveries. Discover more at: https://www.planetary.org/planetary-radio/2026-voyagers-and-the-heliopause See omnystudio.com/listener for privacy information.