TWiS 151: In Search of Alien Megastructures - With Former NASA Chief Scientist, Dr. Jim Green - podcast episode cover

TWiS 151: In Search of Alien Megastructures - With Former NASA Chief Scientist, Dr. Jim Green

Mar 07, 20251 hr 16 minEp. 151
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Episode description

In this episode of This Week in Space, Rod Pyle and Tariq Malik talk with Dr. Jim Green, former NASA Chief Scientist. He discusses how we can search for technosignatures that might indicate advanced civilizations in other star systems, new ideas on Mars sample return, and his fascinating experience consulting on the movie, The Martian! Also: this week's robotic landings on the Moon - one successful, one partly so; what's up with the USAF X-37B mini-shuttle; and recent news on those Energizer Bunnies of space, Voyagers 1&2. Their wings have been clipped a bit, but they just keep going... join us!

News

  • Lunar Landing Week: Firefly Aerospace's Blue Ghost lander achieved a flawless touchdown in Mare Chrisium, the Intuitive Machines Athena lander reached the Moon's south polar region but experienced issues with its navigation radar (and tipped over), and SpaceX's Starship test flight 8 successfully caught its booster for the third time but lost control of the upper stage, resulting in the breakup of the upper stage and debris over the Bahamas and Caribbean.
  • NASA powered down additional instruments on both Voyager 1 and Voyager 2 to extend their remaining power supply, including Voyager 1's cosmic ray system that helped confirm its entry into interstellar space in 2012.
  • The secretive US Space Force X-37B space plane landed at Vandenberg Space Force Base after 434 days in orbit, completing its seventh mission, which tested new orbital capabilities, including aerobraking techniques.
  • A newly released list showcases the world's top ten locations for dark skies and stargazing, with the US only having only one location—in Hawaii—to make the list.

Dr. Jim Green

  • His Career: Dr. Green goes over his former role as NASA's Chief Scientist and highlights key aspects of his career, including running the National Space Science Data Center (NSSDC) and leading NASA's Planetary Science Division, and how his interest in space first began.
  • The Martian: Dr. Green also explains how he got involved as a consultant for Ridley Scott's movie, "The Martian," and how NASA got really involved with the film. He also shares his favorite scene from the movie.
  • NASA's Search for Alien Civilizations: Dr. Green shares how he helped shift NASA's focus from traditional SETI to searching for technosignatures like Dyson Spheres and O'Neill structures in other star systems, securing $10 million in funding for research that could detect megastructures in our astronomical data while noting that humanity may need similar space habitats in 800 million years when the sun makes Earth uninhabitable.
  • Mars Sample Return Strategy: Dr. Green explains how NASA's evolving plan to return samples fropm Mars includes developing Mars Ascent Vehicles that could eventually support human missions while revealing that Perseverance was deliberately designed to place sample tubes on the surface so any nation could retrieve them, making the mission more politically viable with budget offices and Congress.
  • Humanity's Cosmic Future: Dr. Green reveals that he helped create NASA's Commercial Lunar Payload Services (CLPS) program to support new companies for lunar missions. Despite early failures, he emphasized that humanity must utilize space resources and capabilities to

These show notes have been truncated due to length. For the full show notes, visit https://twit.tv/shows/this-week-in-space/episodes/151

Hosts: Rod Pyle and Tariq Malik

Guest: Dr. Jim Green

Transcript

Primary Navigation Podcasts Club Blog Subscribe Sponsors More… Tech A Week of Moon Landing Triumphs and Setbacks

Mar 11th 2025 by John Ashley

AI-created, human-reviewed.

In the latest episode of This Week in Space podcast, hosts Rod Pyle and Tariq Malik dive into what might be described as "Moon Landing Week" – a period that saw both spectacular successes and disappointing setbacks in humanity's renewed push to explore our lunar neighbor.

Firefly's Flawless Landing

The week started with a resounding success for commercial space company Firefly Aerospace. Their Blue Ghost lander executed what Tariq Malik described as a "textbook touchdown" on the lunar plains of Mare Chryseum.

"If you want to talk about a flawless landing... it was absolutely spectacular," Malik enthused during the podcast. The mission, part of NASA's Commercial Lunar Payload Services (CLPS) program, carried ten different NASA experiments to the lunar surface.

The Blue Ghost lander not only touched down smoothly but quickly began returning images, including what Malik called a "haunting picture of its silhouette or shadow on the surface with the Earth up above." The mission is designed to last 14 days (one lunar day) and has already begun testing various experiments, including a vacuum device designed to collect lunar regolith.

As Rod and Tariq discussed, the lander's design may have contributed to its success. With its squat, low center of gravity and wide stance, the Blue Ghost's design seems to have taken lessons from NASA's 1960s Surveyor missions, which demonstrated that wide legs and a low profile work well for lunar landing vehicles.

Intuitive Machines' Challenging South Pole Attempt

Just one day before the podcast recording, space watchers witnessed a very different outcome when Intuitive Machines attempted to land their Athena spacecraft near the south pole of the Moon.

This mission was particularly ambitious, as Tariq explained: "This was actually a really audacious mission." The Athena lander carried NASA's ice-drilling PRIME-1 drill, two small rovers, a hopping spacecraft called GRACE, a Nokia Labs cell tower experiment, and numerous other payloads.

Unlike Firefly's landing site in the smoother mare regions, Intuitive Machines targeted the Moon's challenging south pole, where the terrain is much more rugged and the lighting conditions are especially harsh due to the low sun angle.

"They had new cameras, new navigation systems, all sorts of stuff on it," Malik noted. Despite these improvements over their previous IM-1 Odysseus lander (which had tipped over during its landing earlier in 2024), the Athena mission encountered serious difficulties.

According to the information shared during the podcast, Intuitive Machines believes their navigation radar experienced significant noise issues during descent. While the approach initially seemed promising, the spacecraft hit the ground and tipped over, ending up with its legs pointing upward "almost like a cartoon character," as Malik colorfully described it.

The mission's location in a crater at the south pole proved especially problematic for power generation. Without adequate sunlight to charge its batteries, the spacecraft quickly lost power. "They're not getting the charging that they need to keep the spacecraft alive," Tariq explained, noting that the mission appeared to be over much sooner than planned.

Engineering Challenges and Looking Forward

During their discussion, Rod pointed out that he'd been consulting with various engineers and scientists about these lunar landers, including their mutual friend Pascal. A key concern has been the center of gravity on these vehicles.

Interestingly, Tariq noted that despite appearances, Intuitive Machines' chief technology officer Tim Crane had stated during a post-landing press conference that "the center of gravity is lower than it looks" on their vehicle. Nevertheless, the rugged nature of the south polar region presented challenges that proved too difficult to overcome in this case.

Despite the setback, Intuitive Machines isn't giving up. The company already has plans for IM-3 next year and IM-4 in 2027 under a $117 million contract with NASA. As Tariq noted, "They're going to learn from this... and they're going to stick it, hopefully, on the next attempt."

The Contrasts in Lander Design

Rod highlighted an interesting observation about the two landers: "If you look at the Blue Ghost lander, it's very squat, it has a very wide stance... we learned in the 60s with Surveyor, with that series of landings on the moon, that you wanted really wide legs and a very low machine."

This design philosophy clearly paid dividends for Firefly, while Intuitive Machines' taller, more top-heavy design (which Rod likened to R2-D2) faced greater challenges, particularly in the unforgiving terrain of the lunar south pole.

This week of lunar landing drama was just one segment of a packed episode that also featured discussions about SpaceX Starship's latest test flight, updates on the aging Voyager spacecraft, the return of the X-37B space plane, and a fascinating interview with former NASA Chief Scientist Dr. Jim Green.

To hear the complete conversation, including Dr. Green's insights on Mars sample return missions, the search for extraterrestrial civilizations, and his remarkable career journey from a high school astronomer to NASA's top scientist, check out the full podcast episode of This Week in Space on your favorite podcast platform.

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Mar 7 2025 - In Search of Alien Megastructures
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