Sleep like a hamster, wake up on Mars: Why hibernation is the future of deep space missions

The National

2 days ago

The idea of astronauts snoozing their way to Mars may sound like something straight out of a Hollywood sci-fi movie, but scientists are exploring whether it could one day become a reality.
Researchers in Europe and the US are studying whether slowing a person's metabolism could put them into a state of hibernation that lasts days, or even several weeks.
The concept, known as torpor or synthetic hibernation, would involve reducing the body's metabolic activity to minimal levels, including lowering the heart rate and body temperature. Researchers believe this could help reduce the resources needed during space travel, while also protecting crew members from radiation and the effects of microgravity.
'Every kilogram launched into space is expensive,' said Dr Alexander Chouker, an academic director and physician at Ludwig Maximilian University of Munich and who works closely with the European Space Agency. 'We could cut down the need for food, water, oxygen and even space if you hibernate.'
The agency commissioned studies looking at how hibernation could work during a mission to Mars, including theoretical designs of hibernation pods.
The idea is to place astronauts into torpor for most of the journey, allowing them to wake up as they near their destination.
What is torpor and how does it work?
Some animals can enter a state of torpor naturally. It allows them to conserve energy by lowering their metabolism in response to environmental challenges such as cold or a scarcity of food.
Dr Vladyslav Vyazovskiy, a professor of sleep physiology at the University of Oxford, has worked on studies involving mice and said they can enter a state of torpor when there is a lack of food.
'They calculate how much energy they need and enter this low-energy state for a few hours a day,' he told The National. 'Hamsters do it kind of proactively. They create conditions which remind them of winter.
'For example, when I make their day short and night long, they switch to winter mode, where they start entering torpor every day. My animals enter torpor at room temperature. You don't need to make it cold. The metabolic slowdown comes first, then the body cools down.'
Even though there has been extensive research on animals, scientists still do not how to enable humans to enter the same state. Dr Vyazovskiy said sleep was one of the most important factors, but it is still not clear what kind of effect hibernation would have on a human brain.
'An important barrier is the dramatic change in physiology, in how the body and organism functions, and we need to be really sure that we do not produce a state which will affect the brain or the body negatively,' he said. 'I'm actually surprised that there is so much interest in introducing the state of torpor or hibernation, but nobody cares what the state does to you, so I think it's really important.
'And this is what I studied in my lab – what torpor does to the brain. Does the animal still have memories? Does the brain function is preserved before we can safely apply this to primates or humans?'
Medical potential on Earth
Dr Chouker said that more investment was needed to boost research and the development of technology that could help humans achieve a state of hibernation.
He said it would revolutionise health care on Earth, with any benefits to space travel 'the cherry on the cake'.
'It will change medicine because you can control metabolism, including of a human who's waiting for a specific therapy that needs time," he added. "We could avoid any kind of intensive care or reduce intensive care degeneration and deconditioning effects.'
Could humans hibernate?
Dr Dominique Moser, a biologist also at Ludwig Maximilian University of Munich, said humans may one have had the ability to enter a state of torpor.
'There is some evidence from human history that showed capacity of going into torpor state,' she said. 'There were some bone findings in a cave in Atapuerca [in northern Spain] half a million years ago that showed signs of performing hibernation.'
She said that theory was supported by genetic research that suggests hibernation is not controlled by a single gene, but a complex set of gene expressions triggered under specific environmental conditions.
'It might be that there's some kind of genetic programme that is encoded in plenty of animals, irrespective of species and phylogenetic relationships," Dr Moser said. 'This programme could be encoded in a huge set of mammals such as bears, hedgehogs, apes and even rodents, so why not humans?'
Developing hibernation pods
US company SpaceWorks Enterprises researches human hibernation for the purposes of space travel. It received grants from Nasa in 2013 and 2017 to develop a concept for a hibernation habitat for Mars missions.
Dr John Bradford, chief executive of the company, told The National that it put together a medical team at the time to carry out the study, including researchers from the Mayo Clinic, animal hibernation experts and an astronaut.
He said their findings showed it was possible to develop the sort of hibernation technology typically seen in movies. "It [hibernation] is kind of artificially induced, a low metabolic state, and it involves manipulating the thermal regulatory system of your body," he said.
Among the challenges is finding the right drug combination to temporarily lower the body's thermal set point of 37°C by about 5°C or 10°C.
"That's one of the challenges ... is finding the drugs that can override your body's tendency to basically always keep itself warm and active there, so that you spend a lot of energy doing that," Dr Bradford said.
But even when such medicine and technology is invented, Mr Bradford said there would have to be many human experiments before it can be considered reliable for deep space missions, including tests on the ground and in Earth's orbit.
Astronaut hibernation
The process of inducing human torpor would probably involve several stages – preparation, induction, maintenance and reawakening. Bears, for example, take three to four weeks to fully enter hibernation, suggesting it is a gradual biological process.
'You'd need to get the body ready, perhaps through a combination of environmental cues and pharmacological support,' Dr Chouker said. 'The induction might involve drugs, while the maintenance phase could be supported by automated technology regulating temperature and humidity.'
Light, noise, temperature changes or medication could be used to bring people back out of that state.
Missions to Mars
Space agencies are working towards sending humans back to the Moon, and eventually to the surface of Mars.
Missions to the Red Planet would take seven to 10 months and studies are continuing on how extended deep space missions would affect human psychology and physiology.
SpaceX is developing its Starship rocket, with the aim of sending crewed missions to Mars, or even deeper into space. Placing astronauts into state of hibernation could help them cope with the challenges of long space missions.