March 10, 2025
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How humans can reinvent themselves to live on other worlds
by Alan Boyle, Universe Today
Let's face it: Space is a hostile environment for humans. Even on Mars, settlers might have a hard time coping with potentially lethal levels of radiation, scarce resources, and reduced gravity.
In "Mickey 17"—a new sci-fi movie from Bong Joon Ho, the South Korean filmmaker who made his mark with "Parasite"—an expendable space traveler named Mickey (Robert Pattinson) is exposed over and over again to deadly risks. And every time he's killed, the lab's 3D printer just churns out another copy of Mickey.
"He's dying to save mankind," the movie's poster proclaims.
While it's possible to create 3D-printed body parts for implantation, the idea of printing out a complete human body and restoring its backed-up memories is pure science fiction. Nevertheless, Christopher Mason, a Cornell University biomedical researcher who studies space-related health issues, is intrigued by the movie's premise.
"If you could 3D print a body and perfectly reconstruct it, you could, in theory, learn a lot about a body that's put in a more dangerous situation," he says in the latest episode of the Fiction Science podcast. "I think the concept of the movie is actually quite interesting."
Reinventing the Human Body for Space Exploration
Mason explores the ways in which the human body can be optimized for living in space in a book titled "The Next 500 Years: Engineering Life to Reach New Worlds." He argues that it's up to us humans to ensure the long-term future of life in the universe by taking the tools of evolution into our own hands.
Even if we're able to avoid blowing ourselves up, or succumbing to the effects of climate change, we have only about a billion years before the sun reaches a level of activity that would make Earth unlivable.
"I want to think about preserving life, which necessitates us going to other planets and eventually other stars," Mason says. "Because humans are the only species with an awareness of extinction, this gives us a unique duty toward life … what I call a deontogenic sort of principle, the genetic duty toward all life."
Adjustments to Human Physiology
The good news is that we can adjust to many of the rigors of spaceflight, at least temporarily. Mason and other researchers saw that when they monitored the health of NASA astronaut Scott Kelly during his nearly yearlong stint on the International Space Station in 2015–2016. They compared Kelly's physical and genetic profile with that of his twin brother, Mark Kelly, who was monitored down on Earth.
The NASA-sponsored Twins Study found that Scott Kelly experienced changes in the ways that his genes and his immune system worked while he was in space—possibly because of radiation exposure and other space-related stresses.
"More than 90% of these changes really seemed to come back to normal within a few months of being back on Earth," Mason said. But some of the changes were longer-lasting.
"There's this nagging question of this small percentage of genes and functions that were perturbed that we're still studying to this day in other crews, with SpaceX and other commercial providers," he said.
The Radiative Threat in Space
The stresses of the space environment are likely to become more concerning as explorers and settlers go beyond Earth orbit and our planet's protective magnetic shield. Which gets us back to the things that can kill Mickey 17 and other earthly life forms.
Radiation is the top concern. The studies done to date suggest that astronauts could be exposed to cancer-causing levels of radiation during a three-year mission to Mars and back. Thick shielding could reduce the risk, but Mason suggests using genetics as well.
"For example, tardigrades are these water bears that can survive even the vacuum of space and heavy doses of radiation," he says. "We've made cells in my laboratory that can actually take a tardigrade gene and use it in a human cell, and have this increase of radiation resistance—an 80% decrease in the [DNA] damage that we observe."
If scientists could use CRISPR-style gene-editing tools to insert the tardigrade gene into Mickey's genome, that might head off one of his deaths. In his book, Mason lists other genetic techniques that could improve the vision of space travelers, boost their immune response, or make it easier for them to "hibernate" during a long trip.
Self-Sufficiency in Nutrient Production
"The simplest one, I think, includes the ability to make all of your own amino acids and vitamins," Mason says. "The gene to make vitamin C, for example, is still embedded in all of our DNA. It's just been degraded, and it's no longer functional. But with a few small modifications, you can make your own vitamin C."
As scientists learn more about health-related genes in humans and other species, and improve their gene-editing techniques, Mason thinks the challenges of spaceflight will become less daunting—not only for professional astronauts, but for the rest of us as well.
"You could imagine a case where you can ethically and responsibly and safely modify someone to get them into space," Mason says. "That's not that far away."
And if space travelers run into unexpected challenges on another world—for example, alien microbes on Mars—they wouldn't have to handle it on their own.
"I talk a bit in the book about a 'point-to-point biology' concept, where weird things might appear on Mars, but there's not a lot of resources there to do high-throughput screening, or high-dimensional characterization of the organisms," Mason says.
In that case, the alien microbe's genetic code could be sequenced on-site, using a next-generation version of equipment that's already been tested on the International Space Station. Then the DNA data could be transmitted back to lab researchers on Earth.
"They could synthesize it and then study it there with more resources, and send updates back to Mars," Mason says. "You could imagine this idea of a virtuous cycle of observation, interrogation, study, transfer of data, repeat in a place with more resources—and then send back that knowledge and help the organisms adapt."
That's a world where Mickey wouldn't have to die every day.
Conclusion
As humans venture into the cosmos, the ability to modify our biology to endure the extremes of space travel and habitation may transform our species and our survival. Innovations in genetics, coupled with the growing understanding of space's treacherous environment, will play a crucial role in ensuring the human race can thrive beyond Earth. The continued exploration of ethical genetic modifications will allow future generations not only to visit other worlds but to settle and thrive on them as well, ultimately fulfilling our responsibility as stewards of life in the universe.
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