Sending humans virtually anywhere in space beyond the Moon pushes logistics of health, food, and psychology to limits we’re only just beginning to grasp.

A staple solution to these problems in science fiction is to simply put the void-travelers to bed for a while. In a sleep-like state akin to hibernation or torpor, metabolism drops, and the mind is spared the boredom of waiting out endless empty hours.

Unlike faster-than-light travel and wormholes, the premise of putting astronauts into a form of hibernation feels like it’s within grasp. Enough so that even the European Space Agency is seriously looking into the science behind it.