Episode Details

John and I had the pleasure of welcoming Dr. Robin Andrews from the UK to discuss planetary defense. Robin introduced us to the term “City-Killer,” which refers to an asteroid large enough to cause devastating damage if it were to strike a populated area. While such an impact would result in severe local destruction, it wouldn’t pose a global threat. Robin explained that a "City-Killer" asteroid typically measures between 140 and 160 meters in diameter and provided historical examples of similar impacts.

We also discussed the recent NASA DART mission, which successfully demonstrated the ability to alter an asteroid’s trajectory by deliberately crashing a kinetic energy impactor into it. Robin acknowledged NASA as the leading entity in planetary defense research but also gave credit to ESA and other international organizations contributing to the effort.

During our conversation, Robin addressed the complex and sobering decision-making process involved in either evacuating a threatened area or choosing to absorb the impact — a scenario no one wants to face. He also answered questions about different types of asteroids, including “rubble piles,” and shared insights on potential mitigation strategies. These included nuclear interceptors, gravity tractors, and other developing technologies.

Robin emphasized the importance of early detection and long lead times, stressing that the sooner we identify a threatening asteroid, the greater our chances of successfully deflecting it.

In the second part of the program, John asked Robin what he would do with an unlimited budget for planetary defense. Robin advocated for enhanced infrared observation capabilities, rigorous testing of nuclear interceptors, and maintaining ready-to-launch rockets and missions. He highlighted the Vera Rubin Observatory as a key upcoming asset in the hunt for potential threats like "City-Killers." When asked if a nuclear interceptor could trigger an EMP (electromagnetic pulse), Robin reassured us that this wouldn’t be a concern, as any detonation would occur millions of miles from Earth.

Special thanks to our sponsors:

Northrup Grumman, American Institute of Aeronautics and Astronautics, Helix Space in Luxembourg, Celestis Memorial Spaceflights, Astrox Corporation, Dr. Haym Benaroya of Rutgers University, The Space Settlement Progress Blog by John Jossy, The Atlantis Project, and Artless Entertainment

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