Planetary Radio: Space Exploration, Astronomy and Science

Just three interstellar objects have ever been detected in our Solar System, each arriving from the depths of interstellar space. In this episode, we explore the latest: 3I/ATLAS, a newly discovered interstellar comet first spotted on July 1, 2025. Bryce Bolin, research scientist at Eureka Scientific, joins host Sarah Al-Ahmed to share what makes this object special. As one of the few astronomers who has studied all three known interstellar objects—1I/ʻOumuamua, 2I/Borisov, and now 3I/ATLAS—he offers unique insight into how these rare visitors expand our understanding of planetary systems beyond our own. We also check in with Bruce Betts, chief scientist of The Planetary Society, for a look at the upcoming ESA and JAXA’s Comet Interceptor mission, which may one day chase down a future interstellar comet. Discover more at: https://www.planetary.org/planetary-radio/2025-3i-atlas See omnystudio.com/listener for privacy information.

The 2020s will be a decisive decade for in-space nuclear power. So argues Dr. Bhavya Lal, whose new report reframes the conversation around a simple idea: power, not propulsion, is nuclear's most immediate and disruptive capability. Power is what enables humans to stay and build on distant locales; without an abundance of it, she warns, we will never be more than visitors. But in an era of super heavy-lift capability, does this vision still require a nuclear solution, or can we simply brute-force our future in space with cheaper alternatives? Discover more at: https://www.planetary.org/planetary-radio/bhavya-lal-space-nuclear-powerSee omnystudio.com/listener for privacy information.

How do astronauts get quality sleep in space? Erin Flynn-Evans, director of the Fatigue Countermeasures Laboratory at NASA Ames Research Center, joins Planetary Radio to explore how her team studies sleep, fatigue, and circadian rhythms to keep astronauts healthy and mission-ready. She shares how her team translates sleep science into actionable strategies for NASA crews, and how a chance job as a sleep technician led her on a path to spaceflight research. Later in the show, Casey Dreier, The Planetary Society’s chief of space policy, and Jack Kiraly, our director of government relations, provide a quick update on NASA’s budget and what it means for the agency’s future. Then, Bruce Betts, our chief scientist, joins us for What’s Up to explore how and why our robotic spacecraft sometimes need to power down and rest. Discover more at: https://www.planetary.org/planetary-radio/2025-sleep-in-space See omnystudio.com/listener for privacy information.

On July 14, 2015, NASA’s New Horizons spacecraft made its historic flyby of Pluto, transforming our understanding of this distant world. Ten years later, we’re celebrating that iconic moment and the mission that made it possible. We begin with Alan Stern, principal investigator of the New Horizons mission, who reflects on the mission’s origins, its most surprising discoveries, and what comes next as New Horizons continues its journey through the Kuiper Belt. Then we check in with Adeene Denton, NASA postdoctoral program fellow at the Southwest Research Institute, who just returned from the “Progress in Understanding the Pluto System: 10 Years After Flyby” conference held at the Johns Hopkins University Applied Physics Laboratory. Adeene shares highlights from the event, which brought together scientists to explore new results from New Horizons, JWST, Hubble, and ground-based observatories on Pluto, Charon, and the broader Kuiper Belt. Finally, Planetary Society Director of Government Relations Jack Kiraly joins us with a major update on the ongoing fight to protect NASA science from devastating budget cuts. And don’t miss What’s Up with our Chief Scientist, Bruce Betts. We’re talking Arrokoth, the most distant Kuiper Belt object New Horizons visited after Pluto. Discover more at: https://www.planetary.org/planetary-radio/2025-new-horizons-pluto-flyby-10th-anniversary See omnystudio.com/listener for privacy information.

Author Andy Weir was as shocked as anyone when The Martian became a top bestseller novel in the US. He repeated that achievement with his equally mind-blowing science fiction masterpiece Project Hail Mary. Former Planetary Radio host Mat Kaplan welcomed Andy in April of 2023 for the first livestreamed author conversation in The Planetary Society's member book club. Now, with the film version of Project Hail Mary approaching, we’re proud to begin making these insider interviews available to Planetary Radio listeners. We’ll post them on the third Friday of each month. Join us as we talk with Andy about his obsession with getting the science right while his reluctant and unlikely hero attempts to save humanity from a deep space scourge. Discover more at: https://www.planetary.org/planetary-radio/book-club-andy-weir See omnystudio.com/listener for privacy information.

What happens when scientists, students, space communicators, and refugee engineers float together in zero gravity? Former Planetary Radio host Mat Kaplan joins a remarkable group of flyers aboard a Zero-G flight organized by Space for Humanity. You’ll hear from participants and mentors including Emily Calandrelli, Sian Proctor, and Roxy Williams, as well as Space for Humanity Executive Director Antonio Peronace and Zero-G CEO Kevin Sproge. Together, they share how a few moments of weightlessness offered a powerful shift in perspective. We explore the mission to make space more inclusive, the awe of the “overview effect,” and what it means to carry that inspiration back down to Earth. Then, Bruce Betts joins us for What’s Up. Discover more at: https://www.planetary.org/planetary-radio/2025-mat-kaplan-zero-g See omnystudio.com/listener for privacy information.

The Vera C. Rubin Observatory has shared its first public images, revealing millions of galaxies, stars, and asteroids in stunning detail. Stephanie Deppe, astronomy content strategist at Rubin Observatory, joins us to explain what makes these images so revolutionary, how the observatory works, and what’s coming next as Rubin prepares for its ten-year Legacy Survey of Space and Time. Later in the show, we reflect on the life and legacy of the observatory’s namesake, Vera Rubin, the groundbreaking astronomer who provided the first convincing evidence of dark matter. Jess Soto, STEM Strategies Coordinator at Mount Wilson Observatory and creator of Science Women Shirts, reflects on Rubin’s efforts to open up opportunities for women in space science. Then we close out the show with Bruce Betts in our regular What’s Up segment, featuring the discovery of a brand-new interstellar object, 3I/ATLAS, the third known object to travel through our Solar System from interstellar space. Discover more at: https://www.planetary.org/planetary-radio/2025-first-images-rubin-observatory See omnystudio.com/listener for privacy information.

Have Democrats ceded leadership in space policy? That’s what Mary Guenther believes. She’s the Director of Space Policy at the Progressive Policy Institute and the author of an editorial that claims Democrats have ceded their leadership. She traces the party’s arc from Obama-era reforms to recent data showing that Democrats introduced a third fewer space bills than Republicans in recent years, and proposes ways that the party should embrace this forward-looking field while tying it to their core issues of job creation, supply chains, and climate science. See omnystudio.com/listener for privacy information.

Recorded at the 2025 Humans to the Moon and Mars Summit (H2M2) in Washington, D.C., this episode features two powerful conversations about the future of human space exploration. Hosted by Mat Kaplan, senior communications adviser at The Planetary Society, these panel discussions explore the scientific and diplomatic foundations guiding humanity’s journey beyond Earth. The first panel, Space Science: A Vital National Interest, features James Green, former NASA chief scientist and chair of the Explore Mars advisory board, James Garvin, chief scientist at NASA Goddard Space Flight Center, Britney Schmidt, astrobiologist and associate professor at Cornell University, and John Mather, Nobel Prize–winning astrophysicist and senior scientist for the James Webb Space Telescope. They discuss how space science drives innovation, strengthens U.S. national priorities, and deepens our understanding of the universe, especially in the face of proposed funding cuts. In the second panel, Artemis Accords: International Collaboration in Deep Space, Mike Gold of Redwire, Marc Jochemich of the German Aerospace Center (DLR), Adnan Mohammad Alrais of the Mohammed bin Rashid Space Centre, and Sohair Salam Saber of The Hague Institute for Global Justice explore how diplomacy and shared values are shaping global participation in lunar exploration. The conversation also highlights the Washington Compact, an effort to bring shared values and responsible behavior in space to commercial companies and other non-governmental organizations. We wrap up the show with a new What’s Up segment with Bruce Betts, where we talk about what could happen if the Gateway lunar space station is canceled, and how that would impact humanity’s dreams for Mars. Discover more at: https://www.planetary.org/planetary-radio/2025-H2M2 See omnystudio.com/listener for privacy information.

Alicia Brown from the Commercial Space Federation and Brittany Webster from the American Geophysical Union join the show to discuss NASA’s fiscal year 2026 budget proposal, which aims to slash the agency’s funding by nearly 25%, cut science by 47%, and reduce staffing to levels not seen since 1960. Discover more at: https://www.planetary.org/planetary-radio/fy2026-nasa-budget-discussion See omnystudio.com/listener for privacy information.

The Giant Magellan Telescope (GMT) is poised to become one of the most powerful ground-based observatories ever built. On June 12, 2025, the U.S. National Science Foundation announced that the GMT will enter its Major Facilities Final Design Phase, bringing it one step closer to full construction. This week on Planetary Radio, host Sarah Al-Ahmed speaks with Rebecca Bernstein, Chief Scientist for the Giant Magellan Telescope Organization and astronomer at the Carnegie Institution for Science, about the groundbreaking technology behind GMT and how it will transform our understanding of the Cosmos. Later in the show, Casey Dreier, chief of space policy at The Planetary Society, returns to discuss his new op-ed in Space News on the White House’s controversial Mars plan, and why a bold vision without political consensus is unlikely to succeed. As always, we wrap up with What’s Up with Bruce Betts, Chief Scientist at The Planetary Society. Discover more at: https://www.planetary.org/planetary-radio/2025-gmt See omnystudio.com/listener for privacy information.

Few writers have captured the wonder of science through storytelling as powerfully as Dava Sobel. In this episode, we celebrate her remarkable career and her recent honor as the recipient of The Planetary Society’s 2025 Cosmos Award for Outstanding Public Presentation of Science. Mat Kaplan, senior communications advisor at The Planetary Society, sits down with Sobel for a conversation about the human lives behind great scientific discoveries, from Galileo and Copernicus to the women of the Harvard Observatory and Marie Curie’s lab. Later in the show, Jack Kiraly, our director of government relations, joins us with an encouraging update on our public advocacy campaign to save NASA science. And don’t miss What’s Up with Bruce Betts, where we reflect on the role of science communicators and share a fresh Random Space Fact. Discover more at: https://www.planetary.org/planetary-radio/2025-cosmos-award See omnystudio.com/listener for privacy information.

What does it take to turn a love of space into a global career in science journalism? Sarah Cruddas has done just that. With a background in astrophysics and a passion for storytelling, she’s become a leading voice in space media, covering rocket launches, interviewing astronauts, and writing books that bring the Cosmos down to Earth. In this episode, Sarah shares her path from the U.K. to the front lines of space communication and why she believes storytelling is essential to the future of exploration. She also reflects on the challenges of breaking into the field, the power of listening, and how space can unite people across the globe. Plus, Bruce Betts joins us for What’s Up, where we talk about what makes a great space journalist. Discover more at: https://www.planetary.org/planetary-radio/2025-making-space-matter See omnystudio.com/listener for privacy information.

Former NASA Chief Economist Akhil Rao explains why NASA needs economic expertise to navigate the complex—and often misunderstood—market forces that will determine the success or failure of its private partnerships. As NASA relies ever more on commercial companies to enable its own exploration efforts, it is imperative, Rao believes, to provide clear-eyed perspectives that highlight the challenges and solutions required to reach success. And why NASA puts itself at risk for pursuing faith-based program investments after dissolving the strategy and economics team at the agency a few months ago. Discover more at: https://www.planetary.org/planetary-radio/space-economy-akhil-rao See omnystudio.com/listener for privacy information.

The White House has released its Fiscal Year 2026 congressional budget justification for NASA, and the implications are staggering. If enacted, this proposal would slash NASA’s science program funding by nearly half, cancel dozens of active and upcoming missions, and reduce the agency’s workforce by one-third. Sarah Al-Ahmed is joined by Jack Kiraly, The Planetary Society’s director of government relations, to examine what’s in the nearly 500-page document, what it means for the future of space science and exploration, and how advocates can still act to save NASA science. Then, in What’s Up, Planetary Society Chief Scientist Bruce Betts shares insights on China’s newly launched asteroid sample return mission, Tianwen-2. The spacecraft will rendezvous with near-Earth asteroid 469219 Kamoʻoalewa, offering new scientific opportunities amidst a moment of global uncertainty in space exploration. Discover more at: https://www.planetary.org/planetary-radio/2025-FY-2026-budget-proposal See omnystudio.com/listener for privacy information.

Volcanoes aren’t just an earthly phenomenon. They’re found all across the Solar System. In this compilation episode of Planetary Radio, we explore volcanic and geothermal activity on planets, moons, and distant dwarf planets. You’ll hear from Rosaly Lopes, Nick Schneider, Rae Paoletta, Robbie Herrick, Scott Hensley, and Christopher Glein as they share insights into everything from lava flows on Venus and eruptions on Io to the mysterious heat signatures of icy bodies like Eris and Makemake. This journey spans over 20 years of Planetary Radio, featuring interviews hosted by both current host Sarah Al-Ahmed and founding host Mat Kaplan. Then, our Chief Scientist, Dr. Bruce Betts, returns for What’s Up and shares new findings from NASA’s Juno mission, which recently completed close passes by Jupiter’s volcanic moon, Io. Discover more at: https://www.planetary.org/planetary-radio/2025-volcanic-worlds See omnystudio.com/listener for privacy information.

As debates over NASA's future heat up, questions about the value of space exploration are popping up everywhere. This week on Planetary Radio, we're tackling the tough questions head-on with The Planetary Society's staff, including Casey Dreier, chief of space policy, and Ambre Trujillo, digital community manager. They break down the biggest misconceptions about space science, public versus private investment, and why exploration still matters in an ever-changing world. Then Jack Kiraly, director of government relations, joins us for a space policy update. We discuss the growing movement to save NASA science, how community action is ramping up, and what’s happening behind the scenes on Capitol Hill. And in What's Up with Bruce Betts, we explore some of the most recent NASA spinoffs, technologies developed for space that are making life better here on Earth. Discover more at: https://www.planetary.org/planetary-radio/2025-space-science-under-fire See omnystudio.com/listener for privacy information.

This week on Planetary Radio, we explore the decades-long journey of Kosmos 482, a Soviet-era Venus probe that spent 53 years orbiting Earth before its dramatic return on May 10, 2025. Ben Fernando, a postdoctoral researcher in seismology and planetary science at Johns Hopkins University, joins us to explain the history of Kosmos 482 and how seismology and acoustic sensors are helping scientists detect and locate objects impacting Earth. Then Bruce Betts, our chief scientist, joins us for What's Up, where we look back at the largest human-made objects ever to crash back to Earth. Discover more at: https://www.planetary.org/planetary-radio/2025-kosmos-482 See omnystudio.com/listener for privacy information.

TOI-270 d is revealing secrets about the most common type of planet in our galaxy, sub-Neptunes. Sarah Al-Ahmed is joined by planetary geochemist Chris Glein from the Southwest Research Insitute to discuss his team’s new analysis of its atmosphere, using data from JWST and insights from Earth analogs. Then, The Planetary Society’s Director of Government Relations, Jack Kiraly, breaks down the historic budget cuts proposed for NASA in the U.S. President’s “skinny” budget request, including a 47% reduction to its science program funding. We close out with Bruce Betts and What’s Up. Discover more at: https://www.planetary.org/planetary-radio/2025-toi-270-d See omnystudio.com/listener for privacy information.

No one person knows how to build a spaceship. Dr. Janet Vertesi has seen this firsthand. She’s spent years embedded in NASA science teams, not as a participant, but as an observer. She’s a sociologist who studies the team dynamics of NASA missions. She is alarmed at the prospect of indiscriminate firings at the agency, and at the potential loss of institutional knowledge that won’t easily be rebuilt. Discover more at: https://www.planetary.org/planetary-radio/spe-janet-vertesi-on-threats-to-nasas-group-brain See omnystudio.com/listener for privacy information.