The search for life elsewhere in the Universe is focused now on Mars, our closest planetary neighbor, with the Perseverance mission planned to launch sometime between the end of July and the middle of August. Astrobiologist Sarah Stewart Johnson is a Georgetown associate professor and NASA scientist who has spent her career searching for answers to these questions. Her book Sirens of Mars: Searching for Life on Another World captures the intersection between planetary science and her life's journey, and she joins Host Steve Curwood to explore the big questions that define space exploration and the human species' fascination with Mars. LEARN MORE about this story and everything in our decades of archives at loe.org. We've got audio, transcripts, links, photos and more! . . . PITCH IN with your tax-deductible contribution at https://loe.org/about/donate.html. Thank you for your support! . . . FOLLOW US and join the conversation on Twitter, Facebook, and Instagram. . . .