Scientists are exploring whether humans can hibernate to survive long space journeys, with European Space Agency (ESA) and NASA-backed research suggesting it could reduce radiation exposure, conserve resources, and protect astronauts’ health.
Human hibernation, once the realm of science fiction, is now a serious area of research for space agencies aiming to send astronauts to Mars. The idea hinges on inducing a state of torpor—similar to how animals like bears and ground squirrels survive harsh conditions—where metabolic activity drops, reducing the need for food, oxygen, and water. This could address critical challenges of deep-space travel, including radiation exposure, muscle atrophy, and psychological strain from confinement.
The Science of Hibernation: Lessons from Animals
Researchers are studying how hibernating animals, such as 13-lined ground squirrels and bears, survive for months without food or water.
ESA’s research, involving Jennifer Ngo-Anh, highlights that hibernation could cut a crew’s metabolic rate to 25% of the normal state, drastically reducing the amount of food, water, and oxygen needed for a Mars mission. This would minimize boredom, loneliness, and aggression in a spacecraft, Ngo-Anh notes. The agency’s studies suggest that astronauts could sleep in “soft-shell pods” with controlled temperatures and humidity, mimicking the conditions of natural hibernation.
However, translating these biological mechanisms to humans remains a challenge. Alexander Choukér, professor of Medicine at the Ludwig Maximilians University in Munich, points out that while bears emerge from hibernation with minimal muscle loss, humans are not natural hibernators. He emphasizes the need to understand how to safely induce and reverse torpor without long-term health consequences.
Human Trials and Medical Potential
Recent experiments have tested whether humans can enter a hibernation-like state. In a study led by Clifton Callaway at the University of Pittsburgh’s Applied Physiology Lab, volunteers were placed in a “twilight kind of sleep” using a sedative that reduced their metabolism by 20%. The participants remained able to rise from their bed, shuffle to the bathroom, and ring a bell to ask for food or a drink. This could be a way to protect astronauts during long missions, Callaway says.
The potential benefits extend beyond space travel. Alexander Choukér suggests that induced hypothermia could revolutionize medical care on Earth. It could extend the time doctors have to treat strokes or heart attacks, he explains. ESA’s research also explores how hibernation might protect against radiation, a major risk for astronauts exposed to cosmic rays during interplanetary travel.
Despite these promising developments, scientists caution that human hibernation is not yet feasible. Researchers are investigating drugs and environmental cues that might mimic the process, but the risks of brain damage or organ failure remain unclear.
Challenges and Ethical Questions
One major hurdle is the lack of a “central switch” in the human brain that triggers hibernation, as seen in animals. Vladyslav Vyazovskiy, a professor of sleep physiology at the University of Oxford, says that while mice can enter torpor naturally, we don’t know how to replicate this in humans.
What’s Next for Human Hibernation?
While the dream of hibernating to Mars remains distant, research continues to advance. ESA and NASA are funding studies to develop safe methods of inducing torpor, with a focus on medical applications first. If we can master this technology for Earth-based emergencies, it could pave the way for space travel, says Vyazovskiy.
The next steps will likely involve smaller-scale trials and a deeper understanding of the biological barriers that separate humans from true hibernation.
For now, the prospect of astronauts sleeping their way to Mars remains a tantalizing but unproven idea. As research progresses, scientists will need to balance the promise of hibernation with the realities of human physiology.
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