We give them tasks to do; tasks that resemble what they might have to do on a real Mars mission. For example, there’s the Mars Desert Research Station, operated by the Mars Society and situated near Hanksville, Utah. Man, if there’s a place on Earth that looks a lot like Mars, it’s Hanksville, Utah. It’s so rigorous that when participants want to step outside, they have to put on a bulky and heavy space suit. It's on Earth that we’re gaining the valuable experience to go to Mars, exist on Mars, and thrive on Mars.