Have you ever wondered what it would take for humans to live on Mars? Billionaires like Elon Musk say that we’ll visit before the decade is out, with the long-term goal of building a self-sufficient civilization. What would this effort take? Whether we’re dreaming about terraforming to make a new Earth or just scraping out the most meager of subsistence farms, let’s be honest that living away from our home world wouldn’t be easy.