What will it take to send humans to Mars and back? And what about actually colonizing Mars? Time to Geek Out! Richard talks through the history of manned missions to Mars, starting with Werner Von Braun's own Das MarsProjekt. The story evolves with Robert Zubrin's Case for Mars and the idea (and technology) behind In-Situ Resource Utilization - refuelling ships on Mars by making methane. That's the beginning elements of humans actually living on Mars. Elon Musk talks about creating an independent colony on Mars, requiring one million colonists. What would it take to make that possible?