The Perfect Astronaut Is Changing

To reach Mars, future astronauts will need to maintain uncommon levels of cheer in situations both terrifying and boring. They will be dealing with unknowns the likes of which humanity hasn’t seen since the inception of spaceflight. They will also be trapped with their co-workers in small capsules for years. The commute to Mars alone will take more than 200 days.

The challenges that today’s astronauts face don’t compare: The journey to the International Space Station can be as short as four hours; to the moon, a few days. The average stint at the ISS is six months, and at this point even the riskiest work there is relatively routine. If humans are to even set foot on another planet, Earth might need to send a different type of astronaut. And the most promising candidates might be people whom NASA has long looked to for inspiration, but rarely as hires—outdoor explorers used to navigating challenging and unknown environments, in small groups and relative isolation.

The gap between people who adventure for a living and current astronauts is still wide enough that few would think of a career in space. Joe Dituri, a lifelong diver, biomedical engineering professor, and retired U.S. Naval officer, is one exception. In 2023, he spent 100 days in a 200-square-foot lab, dropped 22 feet below the surface of a murky lagoon, breaking the record for time spent underwater without depressurization. One of his aims, he said early in the experiment, was to help research physical and mental aspects of traveling to Mars.

On his 86th day underwater, I dove down to visit him, following a guide rope through bathtub-warm water until I could duck into the habitat’s entrance. To my right, a voice boomed from a closed hatch leading into the habitat’s kitchen, living room, and office space: Dituri was teaching a biomedical-engineering class. I soon found that, despite the lab’s chugging air pumps, cramped shower, and surrounding darkness, he was simply stoked: about biomedical research, mixed-gas diving, even the salmon he poached in the habitat’s microwave. “When people go, ‘Are you scared?’ I’m like, ‘What’s there to be scared of?’” he told me. “Water’s my jam.”

Dituri did apply to be an astronaut in 2024; he never heard back. Although he meets current qualifications, in many ways he’s not an ideal applicant—he’s so bombastic, for instance, that he’s unlikely to pass the portion of NASA’s intense screening in which applicants live together and evaluate one another’s cohabitation skills. (Kelley Slack, an organizational psychologist who’s worked with NASA, described it to me as “a very dignified Big Brother.”) And his taste for risk—by his count he’s skydived 822 times, despite disliking heights—could count against him. So could his atypical experience, primarily spent underwater as a saturation diver and subjecting himself to hyperbaric environments.

But in the new era of space exploration, that kind of background might offer advantages distinct from those of the engineers and pilots NASA tends to prefer. In May, the Trump administration proposed allocating $7 billion for lunar exploration—likely the first step toward manned missions to Mars—and $1 billion for Mars programs. The political will for this particular ask, though, could well be a casualty of Donald Trump’s public break with Elon Musk, who’s long advocated for colonizing Mars. Musk’s own ambitions include launching SpaceX’s first uncrewed Mars mission by the end of 2026 (a timeline that, like all of Musk’s space-related deadlines, SpaceX is unlikely to meet), and he has imagined the company could eventually take hundreds of thousands of people to the red planet.

If any of these plans come to fruition, the ever-changing magic combination of traits that make up the “right stuff” will need an update.

NASA is thinking ahead. Brandon Vessey, a scientist in NASA’s Human Research Program who provides scientific oversight for spaceflight, told me that the agency already chooses and trains astronauts for six-month missions with longer-duration trips in mind. For a Mars mission, though, “every skill ends up being more important,” he said. So NASA could weigh skills differently than it does now, with some—such as working autonomously and dealing with isolation—“taking on increased importance compared to current missions on the International Space Station.”

And the agency has long had an inkling that terrestrial explorers might thrive under space travel’s extreme job conditions. Apollo crews were dropped in the jungle for training in the ’60s, and current astronauts often train with the National Outdoor Leadership School in places such as the deserts of Utah. NASA research programs frequently look at the experiences of people who have lived in polar stations or submarines. Almost never, though, has the agency actually hired such a person.

The first time NASA chose astronauts for a mission that no one had ever attempted was the 1950s, when Project Mercury was racing to send the first human into orbit. The ideal person needed to withstand being crammed into a capsule the length of two baseball bats, flung into the heavens, then hurtled back, in a fireball reaching more than 3,000 degrees Fahrenheit, straight into the Atlantic Ocean. The actual skills required were so limited that a popular internal term for astronauts was Spam in a can.

For this, NASA considered drawing from a range of unusual professions, including balloonists and mountain climbers. Ultimately the agency worried that adventure professionals would be difficult to locate and require more training, so it chose pilots instead. Until the 1980s, a majority of astronauts had military or aviation backgrounds, or both. Engineers and scientists began joining during the shuttle program, when there was more room onboard and not everyone needed to know how to steer the thing. In the current era of the ISS, essentially a research lab in orbit, most astronauts come equipped with an advanced degree, and nearly half are civilians.

A mission to Mars would not only be longer than any journey yet attempted in space but would also be sprinkled with sub-challenges (mini expeditions, setting up a livable base) in an inhospitable environment with mountainous terrain. This would require a different type of psychological strength: “You need to be accepting of changes to the plan,” says Pascal Lee, the founder of the Mars Institute and a planetary scientist at the SETI Institute. “You’re exploring; you’re lucky if anything went according to plan.” (Lee runs yearly trips to the polar desert on Devon Island in the Canadian Arctic for Mars-related research, partly funded by NASA.) If someone like Elon Musk, the billionaire most interested in Mars, has any say in who should go, his answer is “anyone who wants to go to Mars,” per his recent “The Road to Making Life Multiplanetary” talk. In the past, he’s also praised a high tolerance for risk: “Basically, are you prepared to die? And if that’s okay, then you’re a candidate.” (Musk and SpaceX did not respond to a request for comment.)

NASA’s criteria will certainly be more detailed, but deep-space exploration will require the kind of boundary pushing that Slack likens to historical explorers: “You saw the ship disappear over the horizon and thought, We don’t know if we’ll ever see this person again.” A Mars crew would benefit from people who could provide medical care, build and maintain habitats and food-production systems, troubleshoot gear issues, plan and navigate on-planet expeditions. Assuming maybe five people could fit onboard a ship, each should be an expert at multiple things. “We’re not talking about a jack of all trades,” Lee told me, but “an ace of several trades.” And everyone would need to be able to handle emergencies and share a small habitation in a dangerous environment for long stretches. “Across a wide range of studies, we’ve seen that normal stresses on a team are magnified by the isolated environment,” Vessey, the NASA scientist, said. “What might be a minor irritation in one setting could cause significant issues in a team if they’ve been isolated together for a long period of time.”

Lee emphasized, too, that space simulations that replicate the confined habitat and sometimes length of Mars missions cannot substitute for actual experience with these pressures. “You are really not exercising the stress limits of a crew if they’re not facing real life-and-death decisions and dangers,” Lee said. And foregrounding those skills and experiences when selecting astronauts would net you a lot of expeditionists and outdoor professionals.

NASA came close to choosing a full-time adventurer when it hired Christina Koch, who’s currently on the crew of Artemis II, the United States’ planned mission around the moon. In many ways she’s an unsurprising pick. Her degree in electrical engineering is popular among astronauts, and she began her career at NASA Goddard Space Flight Center. But she also brings an expedition-heavy background. Much of her professional experience has been at remote scientific bases, including multiple tours of Palmer Station and a stint at Amundsen-Scott South Pole Station over the long Antarctic winter. Being hired as an astronaut doesn’t guarantee a specific amount of time in space, but Koch has logged enough that she now holds the women’s record for longest single spaceflight.

Nothing is currently stopping NASA from hiring more people like Koch. In fact, the application criteria are downright forgiving: A couple of years of advanced education or training as well as three years of related experience, in a STEM field or as a pilot, are all that’s required to be chosen to go to space.

To truly consider those who might not check all the usual boxes but whose careers involve survival, navigating mountainous landscapes, or living happily in extreme conditions for long stretches might require a notch more flexibility and active recruitment. The International Federation of Mountain Guides Associations certification, for example, is considered by some to be the doctorate of guiding and is currently held by only about 80 active guides in America who have mastered skiing, mountaineering, and climbing skills, and whose job requires getting along with pretty much anyone while doing all of that. The certification, though, requires no educational degree.

Whenever I asked experts why professional adventurers haven’t been considered for astronaut candidacy, though, they talked about a key drawback: risk taking. “You don’t want people who do it for thrill seeking,” which is why NASA doesn’t hire people who do extreme sports with a real chance of death, Slack said. Even for Project Mercury, when the entire job description was “endure a massive risk,” applicants knew to downplay their daring during interviews: “The psychiatrists always interpreted that as a reckless love of danger, an irrational impulse associated with the late-Freudian concept of ‘the death wish,’” Tom Wolfe wrote in his 1979 book, The Right Stuff. NASA brings everyone home; that’s its thing.

This attitude does run counter to common adventurous behaviors, such as pushing through less-than-ideal conditions, chasing first ascents, or climbing and diving to increasingly dangerous points. But that kind of behavior is an extreme expression of a key personality trait: high-octane, long-term motivation.

And on the flip side of that kind of motivation is one quality that experts told me could be weighed more heavily in astronaut selection for long-distance missions. It’s called “salutogenesis”: a sense of coherence that comes from finding intrinsic value and frequent moments of inspiration in the journey itself. This trait is not necessarily prioritized today. In 2010, the space anthropologist Jack Stuster studied ISS crew members’ journals to better understand their internal life, including what helped them feel adjusted to life in space. Mentioned fewer than 30 times in 545 entries: “beauty/wonderment.” On a longer journey, “you want someone who is going to be able to see the beauty and gain something out of being in space,” Slack said.

Appreciation of beauty might sound whimsical, but it might also be key in helping astronauts thrive in long-distance exploration—and maintaining a spirit of space travel that’s more about curiosity than conquering distant lands. It certainly helped Dituri during his 100 days at the bottom of that murky lagoon.

During my visit, Dituri spent much of the time pointing out the beauty of the world that surrounded us: a hamburger-size Cassiopea jellyfish that feeds belly-up, lobsters hanging out beneath the office porthole, comb jellyfish refracting pulsing rainbows into the dark. His favorite pastime most nights, he told me, was sitting in darkness, shining a flashlight out the porthole and waiting for sea life. Soon a cluster of plankton swarmed the beam. Worms inched over to eat them. The occasional fish darted in for a bite. Lit up against the pitch black of the lagoon, they looked kind of like stars.