Images of rockets blasting off into outer space are pretty awe-inspiring. But what about the bathroom technology that’s inside them? Or the food that is specially engineered to be edible in zero gravity? This is the part of space travel that fascinated writer Mary Roach. She wondered how astronauts keep up their personal hygiene in space without baths or showers? How they cope with isolation so far from earth? Or how sex works without gravity? Our guest Mary Roach talks about her new book Packing for Mars: The Curious Science of Life in the Void and explains why putting human beings into outer orbit is so complicated.