Galileo at 30: How a mission transformed our understanding of Jupiter

Thirty years ago, NASA’s Galileo spacecraft became the first mission to orbit Jupiter, opening a new chapter in our exploration of the outer Solar System. Over eight years around Jupiter, Galileo transformed how we understand Jupiter and its moons, revealing a powerful and dynamic planetary system, uncovering evidence for oceans hidden beneath icy worlds, and reshaping the search for life beyond Earth. To mark the 30th anniversary of Galileo’s orbital insertion, scientists, engineers, historians, and advocates gathered at the California Institute of Technology for a special symposium: Galileo at 30. In this episode of Planetary Radio, host Sarah Al-Ahmed takes you inside that celebration. You’ll hear how Galileo survived seemingly impossible challenges, how its team adapted when things went wrong, and how its discoveries reshaped planetary science. You’ll hear from key voices in Galileo’s story, including historian Erik Conway, project manager Bill O’Neil, magnetometer principal investigator Margaret Kivelson, Europa Clipper Project Scientist Bob Pappalardo, and Dragonfly mission Principal Investigator Elizabeth “Zibi” Turtle, along with reflections from many others whose lives and careers were shaped by this remarkable mission. Together, they tell the story of Galileo not just as a spacecraft, but as a shared human effort, one whose legacy continues to guide exploration today. Discover more at: https://www.planetary.org/planetary-radio/2025-galileo-at-30See omnystudio.com/listener for privacy information.

Why do we explore space, and why does science matter in the first place? In this Space Policy Edition rerun, Planetary Society Chief of Space Policy Casey Dreier revisits a deeply influential 2020 conversation with philosopher and ethicist J. S. Johnson-Schwartz, author of The Value of Science and Space Exploration. As debates over NASA’s budget and the future of space science continue to resurface, this conversation remains strikingly relevant. Dr. Johnson Schwartz makes a compelling philosophical case that science itself is not merely useful or beneficial, but a moral obligation. Beyond economic returns, technological spinoffs, or national prestige, the pursuit of knowledge has intrinsic value, and public space agencies play a critical role in representing that shared human interest. Discover more at: https://www.planetary.org/planetary-radio/the-moral-case-for-spaceSee omnystudio.com/listener for privacy information.

The 2025 International Mars Society Convention convened at the University of Southern California this October for three days of passionate discussion about humanity’s future on the red planet. Speakers explored science, policy, technology, AI, synthetic biology, and the long-term path toward becoming a multi-planet species. In this episode, Mat Kaplan, senior communications adviser at The Planetary Society, shares his conversations with speakers and guests at the Convention. We hear from Robert Zubrin, founder of The Mars Society, who delivered a fiery call to protect NASA’s science programs in the face of unprecedented budget cuts. Humphrey “Hoppy” Price, Chief Engineer for NASA’s Robotic Mars Exploration Program at the Jet Propulsion Laboratory, updates us on the future of Mars Sample Return and new mission architectures. Keynote speaker Dex Hunter-Torricke, a longtime communications leader for SpaceX, Meta, and other major tech organizations, reflects on AI’s promise and peril, and why Mars remains a beacon of hope for humanity’s future. Biologist and technologist Tiffany Vora, vice president for innovation partnerships at Explore Mars, and Erika DeBenedictis, biologist and founder of Pioneer Labs, reveal breakthroughs in synthetic biology and engineered microbes that could help future Martians survive. Steve Benner, chemist and founder of the Foundation for Applied Molecular Evolution (FfAME), revisits the Viking lander experiments and makes a provocative case that we may have found Martian life nearly 50 years ago. Architect Melodie Yashar, CEO of AENARA and a pioneer in 3D-printed habitat research, shares progress in additive construction on Earth and Mars. James Burk, executive director of The Mars Society, discusses advocacy, analog research stations, and the organization’s expanding international footprint. Finally, we meet Sasha, a 13-year-old presenter whose enthusiasm offers a bright glimpse of the next generation of explorers. We wrap up the show with What’s Up with Bruce Betts, chief scientist at The Planetary Society, with a discussion of perchlorates in the Martian soil. Discover more at: https://www.planetary.org/planetary-radio/2025-mars-society-conventionSee omnystudio.com/listener for privacy information.

NASA’s twin ESCAPADE spacecraft have finally launched on their journey to Mars. Designed to study how the solar wind interacts with Mars’ patchy magnetic fields and drives the loss of its atmosphere, ESCAPADE is NASA’s first dual-spacecraft mission to the Red Planet and a major milestone for the SIMPLEx program’s small, low-cost planetary explorers. The mission began its voyage aboard Blue Origin’s New Glenn rocket after several weather and space weather delays, marking the vehicle’s first science launch. We begin with Ari Koeppel, AAAS Science & Technology Policy Fellow and Space Policy Intern at The Planetary Society, who was at Cape Canaveral for the prelaunch activities. Ari shares what it was like to navigate repeated scrubs and even a powerful solar storm, along with the emotional experience of watching a spacecraft carrying an instrument he helped build begin its voyage to Mars. Next, we are joined by Dr. Rob Lillis, ESCAPADE’s Principal Investigator and Associate Director for Planetary Science at UC Berkeley’s Space Sciences Laboratory. Rob explains how ESCAPADE aims to unravel Mars’ complex space environment using two coordinated orbiters, why its measurements are key to understanding atmospheric escape, and how its innovative trajectory made the mission possible after the loss of its original rideshare opportunity. Finally, Dr. Bruce Betts, Chief Scientist of The Planetary Society, returns for What’s Up to talk about why Mars produces aurora even without a global magnetic dynamo. Discover more at: https://www.planetary.org/planetary-radio/2025-escapadeSee omnystudio.com/listener for privacy information.

This week on Planetary Radio, we’re sharing a special conversation from our friends at the Smart Girl Dumb Questions podcast. Host Nayeema Raza sits down with The Planetary Society’s Chief of Space Policy, Casey Dreier, to explore one of the most common questions in space exploration: Why does space matter, and is it really worth the cost? Casey breaks down how space exploration impacts daily life, from GPS and weather forecasting to cutting-edge technologies and scientific discoveries that could reshape our future. Together, Nayeema and Casey unpack the big ideas behind NASA’s ~$25 billion budget at a moment when U.S. national priorities are shifting. Stick around after the interview for a special U.S. Thanksgiving-week edition of What’s Up with Chief Scientist Bruce Betts. Discover more at: https://www.planetary.org/planetary-radio/2025-smart-girl-dumb-questionsSee omnystudio.com/listener for privacy information.

There was a time when almost everyone, from Alexander Graham Bell to the Wall Street Journal, believed there was a supremely intelligent civilization on Mars, one that was probably trying to talk to Earthlings. Most of this belief could be traced to an amateur astronomer and charismatic speaker named Percival Lowell. David Baron tells this story in “The Martians: The True Story of an Alien Craze that Captured Turn-of-the-Century America,” the product of seven years of research into this strange chapter of history. He shares many of the most surprising, fascinating, and very entertaining details, including much that had been lost to history, in this book club conversation with Mat Kaplan. Discover more at: https://www.planetary.org/planetary-radio/book-club-david-baronSee omnystudio.com/listener for privacy information.

When his filmmaking career stalled during the pandemic, Toby Lockerbie turned to the one place that had never stopped inspiring him: the Universe. With no background in visual effects, he taught himself the tools needed to transform complex space science into cinematic stories using everyday objects and beautifully crafted visuals to make the Cosmos feel human. His channel, Epic Spaceman, now reaches millions and has earned multiple Webby Awards for its innovative approach to visualizing scale, awe, and accessible science. This week on Planetary Radio, Toby joins host Sarah Al-Ahmed to discuss the creation of Epic Spaceman, how visual metaphors can change how we understand the Universe, and why awe remains one of the most powerful tools for science communication. Then we welcome Bruce Betts back for What’s Up, where we reflect on the end of the Japanese Aerospace Exploration Agency’s Akatsuki mission to Venus. Discover more at: https://www.planetary.org/planetary-radio/2025-epic-spacemanSee omnystudio.com/listener for privacy information.

The Planetary Society heads to TwitchCon 2025 to explore how scientists and educators use livestreaming to share the excitement of discovery. We begin with Moohoodles, one of Twitch’s pioneering space science streamers and co-host of the live panel “The Planetary Society: Space, Time, and You.” She explains how she built a thriving community around astrobiology and space exploration long before Twitch even had a Science & Technology category. Then we share moments from the panel, featuring a special video message from Bill Nye, CEO of The Planetary Society, and highlights of how livestreaming helps inspire new audiences to look up. At the Science & Technology Meet and Greet, Sharkg33k and Paleontologizing explain how their streams connect life on Earth to exploration beyond our planet. Later, Jack Kiraly, The Planetary Society’s Director of Government Relations, joins the show for a Space Policy Update on Jared Isaacman’s renomination as NASA Administrator, examining what it could mean for the agency’s leadership and direction. The episode wraps up with What’s Up with Bruce Betts, The Planetary Society’s chief scientist, celebrating the third anniversary of the end of the LightSail 2 mission and sharing a new random space fact. Discover more at: https://www.planetary.org/planetary-radio/2025-twitchconSee omnystudio.com/listener for privacy information.

In 1996, a controversial claim of fossilized life in a Martian meteorite ignited a golden age of Mars exploration. Nearly 30 years later, a potential biosignature detected by the Perseverance rover at Jezero Crater has sparked…nothing, not even a formal effort to revive the beleaguered robotic Mars Sample Return project. Why did the claims surrounding the Allan Hills meteorite (which were ultimately rejected) kick off 25 years of unprecedented robotic exploration of the Red Planet? And why did the discovery at Cheyava Falls fail to ignite the same level of interest? Lou Friedman, former Executive Director of The Planetary Society and longtime proponent of Mars Sample Return, joins the show to contrast these to tipping points of Mars exploration, and argues why space scientists should seize this discovery to push for a scientific future at the Red Planet. Discover more at: https://www.planetary.org/planetary-radio/spe-lou-friedman-on-msr-and-tipping-point-eventsSee omnystudio.com/listener for privacy information.

If we ever meet intelligent extraterrestrials, will we even be able to talk about physics? Physicist Daniel Whiteson of UC Irvine and cartoonist Andy Warner join Sarah Al-Ahmed to explore one of science’s strangest and most profound questions: if alien civilizations exist, would their understanding of the Universe look anything like ours? Their new book, “Do Aliens Speak Physics?”, discusses the nature of knowledge itself, asking whether math and physics are truly universal, or if even our most “objective” truths are shaped by our human perspective. Together, they consider what it would take to communicate with alien intelligence and how humor and illustration can make those big cosmic ideas feel surprisingly down-to-Earth. Then, stick around for What’s Up with Bruce Betts, as we discuss how difficult it is to explain physics to humans, let alone extraterrestrial life. Discover more at: https://www.planetary.org/planetary-radio/2025-do-aliens-speak-physicsSee omnystudio.com/listener for privacy information.