In Andy Weir’s thought-provoking novel Project Hail Mary, two of the three astronauts meet a tragic fate during a lengthy interstellar journey. But why did this happen? Haig Aintablian, an emergency physician and flight surgeon at UCLA’s space medicine program, suggests that the astronauts’ four-year-long medically induced comas could be a significant factor. While the idea of sleeping through space travel sounds appealing—waking up just in time to land on a recent planet—Aintablian cautions against the viability of such a method for human survival.
“How cool would it be if you went to sleep a few hours after launch and woke up right as you arrived at your destination?” he muses. However, he adds, “I don’t think keeping the human alive and in a comatose state is necessarily the best option.” This raises the question: how can humans realistically survive the rigors of interstellar travel?
Understanding the Risks of Extended Comas
When considering extended space travel, it’s essential to recognize the human body’s limitations. Aintablian points out that astronauts in a comatose state are at risk for serious health complications, including blood clots, muscle atrophy, and infections resulting from medical devices. The body is not designed to be stagnant, making such a state dangerous for long durations.
Exploring Alternatives: Freezing and Hibernation
One intriguing alternative to extended comas is the concept of freezing astronauts for the duration of their journey. Aintablian suggests that if technology advances to the point where humans can be safely frozen and later thawed, it could solve many challenges of interstellar travel. However, this approach similarly faces significant biological hurdles. According to Matthew Regan, an integrative biologist from the University of Montreal, human hearts struggle to function at temperatures below 28 degrees Celsius. While some individuals have survived brief episodes of extreme hypothermia, enduring such conditions over several years poses an entirely different challenge.
Another potential solution is to harness the natural hibernation process observed in certain mammals. For instance, arctic ground squirrels can lower their body temperatures below freezing during periods of torpor, significantly slowing their metabolism to just 2% of its normal rate. Regan notes, “They’re just barely ticking over. It’s like pilot light levels.” In contrast, hibernating bears drop their body temperatures to around 31°C to 32°C (approximately 88°F to 90°F), allowing them to conserve energy without suffering from the detrimental effects of inactivity.
The Benefits and Challenges of Hibernation
If humans could similarly reduce their metabolic rates, interstellar travel would require fewer resources, making it a viable option for long journeys. Regan posits that being in a state of torpor could provide some protection against the harmful effects of ionizing radiation, a significant concern for space travelers.
However, a continuous hibernation during an entire trip is likely impractical. Ground squirrels and other hibernators periodically awaken to rewarm their bodies and engage in movement, which may be crucial for maintaining muscle health and cognitive function. Neurochemist Kelly Drew from the University of Alaska Fairbanks emphasizes the importance of these awakenings, suggesting they promote muscle regeneration and brain health.
Navigating the Health Risks of Space Travel
As fascinating as these concepts are, they come with their own sets of challenges. For instance, hibernation biologist Hannah Carey from the University of Wisconsin–Madison warns that packing on weight before hibernation, which bears do, can lead to elevated cholesterol levels that may result in heart disease for humans. In her research, some ground squirrels gained excessive weight but died mysteriously during hibernation, raising concerns about the physical toll that this state could take on astronauts.
None of this, however, explains the fatalities depicted in Project Hail Mary. Weir himself has clarified that the astronauts’ deaths were not due to biological failure but rather a technical malfunction. “Being in a coma for four years is a dangerous proposition in the best of times,” he explains. “A small tech failure can lead to catastrophic results, which it did in this case.”
As we look towards the future of space exploration, these discussions not only highlight the imaginative aspects of science fiction but also the practical implications for real-life astronauts. Understanding the medical, technological, and biological hurdles is crucial as humanity ventures deeper into space.
With the film adaptation of Project Hail Mary set to hit theaters soon, it invites audiences to reflect on the complexities and challenges of interstellar travel. As we continue to explore the universe, the conversation about how to preserve astronauts safe and healthy during long voyages will remain vital.
