The state of suspended animation that astronauts enter during long-haul space flights is a staple of science-fiction movies. But now the European Space Agency (ESA) wants to turn it into reality. Agency staff are planning future research into the possibility of inducing a hibernation-like state in humans. “We are not sure whether it is possible,” says Marco Biggiogera, an expert on hibernation mechanisms at the University of Pavia, Italy, who is advising ESA. “But it’s not crazy.”