Welcome back to Season 2 of my weekly live QA. Your chance to ask me your questions about space and astronomy... live. You wanted to know about recent news about astronauts mixing concrete in space, the formation of craters on Titan, and what might be the difficulties of people going to the Moon or Mars? 04:22 Mixing concrete on ISS? 12:22 Formation of Titan's lakes14:02 Why don't millionaires and billionaires live on the Moon?