Humans might be able to hibernate during space travel

A teenager joins a line of people boarding a spaceship. Once on board, she approaches a bed, crawls in, closes the lid and falls asleep. Her body is frozen for a trip to a planet several light-years from Earth. A few years later she wakes up, still the same age. This ability to put her life on pause while asleep is called “suspended animation.”

Scenes like this are a staple of science fiction. There’s plenty of other ways that suspended animation has touched our imagination, too. There’s Captain America, for instance, who survived nearly 70 years frozen in ice. And Han Solo was frozen in carbonite in Star Wars: The Empire Strikes Back. The Mandalorian’s main character brings in some of his bounties cold, too.

All of these stories have something in common. People enter an unconscious state in which they can survive for a long time.

Hibernation may look like a deep form of sleep, but it’s not sleep. As an animal hibernates, it chills its body and slows its heart rate and breathing. Metabolism also slows. To do this, an animal must turn on and off certain genes when they hibernate. Those genes do things like controlling whether an animal burns sugars or fats for fuel. Other genes are involved in keeping muscles strong

Hibernation: Secrets of the big sleep:

Some animals’ body temperatures drop below freezing when they hibernate. Humans may not survive that chill, says John Bradford. He is the chief executive officer of SpaceWorks, a company in Atlanta, Ga. Bradford once proposed a space capsule where astronauts could hibernate. He thinks NASA could use such a capsule to send people to Mars