In science fiction, when people need to travel immense distances through outer space and don’t have a wormhole nearby, they bed down for a very long nap. For this, the heroes of films like "Aliens," "Avatar," "Interstellar," and "Passengers," have put themselves into suspended animation.
It would be convenient if real astronauts could hop in a sleep pod and wake up years later without aging a day. The bad news is we’re nowhere near this reality.
But scientists and engineers are collaborating with NASA and other space agencies to develop suspended animation projects for missions to Mars and beyond. Instead of being frozen in time, though, astronauts could be knocked out for weeks or months in a state called torpor that resembles hibernation.
If these projects are successful, ships could be more compact and more sparsely equipped, making them less expensive to propel through space. Astronauts could also spare their physical and mental health. And torpor could help us here on Earth, too.
The Case For Torpor
On a voyage to deep space, humans will be more demanding cargo than a rover or satellite. For one, we must eat. We also need room to move around and tend to chafe at sharing cramped quarters for long periods. And our bodies will be bombarded with cosmic rays and face numerous health issues caused by low gravity, including loss of bone density and muscle mass.
Putting astronauts into a hibernation-like state could help with some of these problems.
“The core characteristic of hibernation is that you suddenly stop consuming energy,” says Matteo Cerri, a physiologist at the University of Bologna in Italy. “If you’re not consuming any fuel you’re going to cool down.”
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During hibernation, an animal’s metabolism grinds to a near standstill. The heart beats more slowly and body temperature drops. The hormones and composition of the blood are altered. Breathing, cell replication, and brain activity slow. “It’s like a movie that progressively slows down," Cerri says. "Every frame gets slower and slower."
But humans can’t hibernate. “We’re just trying to make them appear to hibernate, or creating the benefits…of hibernation,” says John Bradford, president and COO of SpaceWorks Enterprises, an Atlanta-based aerospace engineering firm working with the NASA Innovative Advance Concepts (NIAC) Program.
If the crew could spend most of
the flight in torpor, they would need less food and could occupy a
smaller living space. Shipping anything into space is incredibly
expensive because of added fuel costs for each extra pound, so a smaller
spaceship would be a huge advantage.
Torpor could help fit more people on smaller ships to help rapidly populate space colonies. SpaceWorks
It might also be more pleasant for the astronauts.
“If you’re in a small tin can with the same other three people for nine months and you can’t really move about the cabin…it may actually be that sleeping for 14 days is the preferred way to go,” says Jason Derleth, program executive of NIAC.
Torpor could also have health benefits. While hibernating, animals don’t suffer muscle atrophy or bone degeneration from lack of use, although it’s not clear why. And there’s evidence that animals are less vulnerable to radiation during hibernation. So torpor might give astronauts added protection during spaceflight. On the other hand, a lowered metabolism means the body may not repair itself as quickly, so radiation damage might be more profound, Derleth says.
Having the crew stay in one place would make it easier to shield that portion of the ship from radiation since it would be incredibly expensive and impractical to shield a whole spacecraft.
How Will It Work?
The European Space Agency is working with Cerri and his colleagues to study suspended animation. They have already used drugs to shut off a brain area that controls metabolism in non-hibernating rats, sending the rodents into torpor.
Meanwhile, SpaceWorks has a team of engineers, former astronauts, physicians, and hibernation researchers that are pondering how to send astronauts into torpor safely and how a spacecraft could be designed to accommodate them.
SpaceWorks’ ideas build on a procedure used in emergency rooms called therapeutic hypothermia, in which the body is cooled to prevent brain damage after crises like cardiac arrest. But this has been done for days, not weeks or months. And it’s unclear whether it causes side effects because the people who receive this treatment are already ill.
