Take the cold tolerance of bacteria that thrive in arctic ice, add the ultraviolet resistance of tomato plants growing high in the Andes mountains, and combine with an ordinary plant. What do you get? A tough plant “pioneer” that can grow in Martian soil. Like customizing a car, NASA-funded scientists are designing plants that can survive the harsh conditions on Mars. These plants could provide oxygen, fresh food, and even medicine to astronauts while living off their waste. They would also improve morale as a lush, green connection to Earth in a barren and alien world.