Interstellar Travel Poses Biological Challenges

Coma, hibernation, and cryopreservation may be key to long-duration space missions, but each comes with significant risks.

Published on Feb. 22, 2026

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As the allure of interstellar travel grows, scientists are grappling with the physiological challenges of keeping humans alive during years-long voyages to distant stars. While medically induced comas, hibernation, and cryopreservation offer potential solutions, each approach carries significant risks, including blood clots, muscle atrophy, and the inability to safely freeze and thaw the human body. Experts caution that the human body is not designed for prolonged inactivity, and even mimicking the hibernation patterns of animals like bears and ground squirrels presents complex obstacles. Overcoming these biological hurdles will require innovative solutions and a deep understanding of human physiology.

Why it matters

Interstellar travel is no longer confined to science fiction, and as the possibility of reaching distant stars becomes more realistic, the need to address the physiological challenges of long-duration space missions is increasingly pressing. Exploring solutions like comas, hibernation, and cryopreservation could unlock the potential for human exploration beyond our solar system, but the risks and limitations of these approaches must be thoroughly understood.

The details

Medically induced comas, while appealing in theory, carry significant risks, including the development of dangerous blood clots, muscle atrophy, and increased susceptibility to infections. Induced hibernation or cryopreservation, where astronauts are frozen for the duration of the trip, remain in the realm of theoretical possibility, as the human body struggles to function at the extreme temperatures required. A more plausible alternative may lie in mimicking the hibernation patterns of animals like bears and ground squirrels, which can dramatically slow their metabolism during torpor. However, even this approach is not without its challenges, as these animals periodically arouse from their hibernation, a process that may be crucial for muscle regeneration and brain health in humans.

  • The novel 'Project Hail Mary' and its film adaptation have sparked renewed debate about the challenges of long-duration space travel.
  • Experts caution that maintaining human life in a comatose state for extended periods is far from a simple undertaking.

The players

Dr. Haig Aintablian

An emergency physician and flight surgeon at UCLA's space medicine program.

Dr. Matthew Regan

An integrative biologist at the University of Montreal who points out the challenges of human hearts functioning below 28° Celsius.

Kelly Drew

A neurochemist at the University of Alaska Fairbanks who suggests that periodic awakenings during hibernation may be crucial for muscle regeneration and maintaining brain health.

Hannah Carey

A hibernation biologist at the University of Wisconsin–Madison who cautions against simply 'fattening up' astronauts before a long voyage, as excessive fat reserves can lead to high cholesterol levels.

Andy Weir

The author of the novel 'Project Hail Mary', who explained that the deaths of the astronauts in the story were not due to the limitations of human physiology, but rather a consequence of the inherent risks associated with maintaining life support systems for extended periods.

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What they’re saying

“How cool would it be if you went to sleep a few hours after launch, and you woke up right as you arrived on the planet or the celestial body that you're approaching?”

— Dr. Haig Aintablian, Emergency physician and flight surgeon at UCLA's space medicine program

“The human body is not designed to just be a stagnant blob.”

— Dr. Haig Aintablian, Emergency physician and flight surgeon at UCLA's space medicine program

“It was a tech failure. Being in a coma for four years is a dangerous proposition in the best of times. So a small tech failure can lead to catastrophic results. Which it did in this case.”

— Andy Weir

What’s next

Researchers continue to explore innovative solutions and study the intricate mechanisms that govern human physiology to overcome the biological hurdles of long-duration space travel.

The takeaway

While the dream of reaching distant stars remains a significant challenge, the ongoing research into hibernation, cryopreservation, and metabolic control offers a glimmer of hope for future interstellar explorers, but significant risks and limitations must be addressed.