The current drive for a Mars colony revolves around two central axes: one is a fear of existential risk and the other is a search for existentialism. On the former, philosophers and probabilists remain deeply concerned about humanity’s Achilles heel: that our entire existence depends on the sustenance of a single blue dot in the Milky Way. Humanity’s fate is fundamentally tied to this single rock, which gives little redundancy from an asteroid strike, nuclear winter, or pandemic. At the same time, many entrepreneurs hear a rallying cry when they think about a Mars colony, arguing that a bold and long-term project is precisely what is needed to galvanize humanity to work together, overlook our internecine differences and find transcendence amidst the celestial cosmos. Even if outside our lifetime, a drive toward a space colony could be an existentialism that offers meaning and sustenance to our lives. In this second and final episode, Zack Weinersmith, who along with his wife Kelly Weinersmith are the authorial duo of A City on Mars, join host Danny Crichton and Lux’s scientist-in-residence Sam Arbesman to talk more about their negative prognostication for a Mars colony. Taking a more optimistic view, we also talk with Zach about what we should be doing to prep for a colony, including collecting more laboratory data and expanding science’s understanding of life under microgravity conditions.