A hundred meters below the surface of the moon lie caves untouched by humans. They were discovered about ten years ago, but space agencies want to send robots to investigate these mysterious cavities before astronauts venture in. "On the moon's surface, the temperature is 150 degrees above zero during the day and 150 degrees below zero at night," says Lucas Froissart, who recently completed a Master's degree in mechanical engineering at EPFL. "In these subterranean caves, which can be reached through natural, vertical pits, the temperature is -30 degrees and there's no radiation. Since the climate is constant and tolerable for human beings, these tunnels could conceivably serve as base camps."