The astronauts arrived at the Mars base one by one, dressed in faded orange spacesuits. After they walked through a pressurized chamber and removed their helmets, they were blasted in the face with some sort of decontaminating mist. When the cyclist Lance Armstrong walked in, one of his comrades was in awe. “The fact that we have an astronaut is so crazy,” Ariel Winter, an actor who appeared on Modern Family, told another contestant, who was visibly confused. Winter had mistaken this Armstrong for Neil Armstrong, the first man on the moon, who died in 2012.

So began the first season of Stars on Mars, a Fox reality show that sent celebrities to “space” (the Australian desert), and whose season finale airs tonight. Over the course of 12 episodes, viewers have watched the participants live as Mars astronauts would, on freeze-dried meals and a 20-minute communication delay with the rest of Earth, fertilizing potato crops with (fake) human waste, à la The Martian. The point of the show is for contestants to work together when things go wrong—a communication tower goes down, a robot dog needs to be rescued, the habitat’s precious garden catches fire. If the group decides you aren’t “mission critical,” you go home. The winner gets the prize of being declared “the brightest star in the galaxy.”

Like most reality TV, Stars on Mars is cringy, mindless fun. It might also be the most believable reality show I’ve ever seen. We humans still have much to figure out before dispatching a real-life mission to Mars. We have to build the spaceships and rockets to get there, find a way to protect astronauts from intense radiation on the flight over, and figure out how they’ll live off the inhospitable environment once they land. Stars on Mars highlights one of the most significant challenges of extended spaceflight, one that’s often overlooked: the crew itself, with all of its personalities, opinions, and feelings. There will be drama on Mars.

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NASA knows this. Psychologists know this. For years, they've been running space simulations on Earth designed to study cognitive performance, interpersonal interactions, and team dynamics in an isolated, inescapable environment; the latest began in June, with four volunteers prepared to spend 378 days in a 1,700-square-foot outpost, only venturing out in spacesuits, as they do on Stars. Travelers to Mars will be stuck with one another for some seven long months—each way. Such a mission is the ultimate group project, and picking the right people is crucial. Everything researchers learn from simulations will someday be incorporated into guidelines for keeping astronauts nice and stable on long-term space missions, and not tearing at one another’s throats.

The researchers who run simulations, not unlike reality-TV producers, introduce “resource limitations, equipment failure, communication delays, and other environmental stressors” to see how the participants handle them, as NASA has in its new Mars experiment. In a 2017 simulation, NASA put four recruits inside a tiny habitat for 45 days and kept them quite sleep-deprived in order to study the effects of crew fatigue. “After about a week, it was more like grunts than actual conversation,” John Kennard, one of the participants, told me back then. The crankiness led to some misunderstandings, the participants told me. One day could feel like an entire week. People got on one another’s nerves. All of this, in 650 square feet.

In 2018, I reported on a NASA-funded Mars simulation in Hawaii that was cut short after one of the participants sustained an electric shock. The others covered the shivering, injured crew member with blankets and called 911. When they heard an ambulance outside, one of them moved toward the exit. That participant, Lisa Stojanovski, told me that the simulation’s commander stopped her, warning her that whatever the crew did next—such as leaving the habitat without a spacesuit, for example—could compromise the experiment. “I actually lost my temper at this point,” Stojanovski told me. “I don’t remember exactly what I said, but there were some curse words involved.” The crew eventually opened the door, allowing first responders inside.

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Real-life astronauts on Mars might behave even less predictably. They won’t have the same kind of oversight as crews on the International Space Station, or even on the moon. They will make many decisions without constant support from mission controllers, and perhaps sometimes without their approval too. “That’s the complexity of humans. They are going to do things on their own, maybe outside of the mission rules,” Jennifer Fogarty, the former chief scientist at NASA’s Human Research Program, the office that helped fund the failed Mars simulation, once told me. “So thinking you can keep them in this tight little box of emotions is unrealistic.”

Unlike the Stars on Mars contestants, the crew of a real Mars mission would not consist of strangers. The astronauts will have spent months, perhaps years, training together, and they would have signed up—to borrow a term from another reality-TV show—for the right reasons. They will have undergone extensive psychological screening and been selected for roles that suit their skills and temperament. All of that, however, is no guarantee of a good time. “You can select a crew all you want, get the right fit and mix, but there’s too many variables when it comes to human beings,” Raphael Rose, the associate director of the Anxiety and Depression Research Center at UCLA, told me in 2018.

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Some of those variables showed up on Stars. The drama was mostly minor and predictable; contestants would get annoyed when they felt that their fellow crew members weren’t pulling their weight on field missions. But at times, the tension rocketed up. In one episode, Armstrong, chatting with another contestant, the professional wrestler Ronda Rousey, declared that trans athletes should not compete alongside cis ones. (No, this had nothing to do with space missions.) The rest of the crew pushed back. Armstrong clashed in particular with Winter, and when the group picked Winter to be base commander—a position that rotates each week—Armstrong threatened to leave. “I’m not living in this hab another day with certain people,” Armstrong said; he quit a few episodes later. (This guy may not be cut out for Mars.)

Despite the fact that it’s a silly show stuffed with celebrities and edited to look as dramatic as possible, Stars on Mars may not be the worst thing to watch if you’re planning a crewed Mars mission. Even Dwayne Day, a respected historian of the American space program, thinks the series could teach us about the personalities best suited for expeditions beyond Earth—despite the fact that he’d expected to hate it. The show is “consistent with the requirements of a real space mission,” Day wrote in The Space Review last month. “A commander who makes choices based upon who they like rather than who is most capable is a lousy commander. A crewmember who doesn’t always do their best during an important task that the rest of them depend upon is a danger to their safety.”

Luckily for psychologists, no Mars spaceship is idling its engines on a launchpad, waiting only for someone to crack the secrets of human relationships before heading out. A Mars mission is still many years—decades, probably—from taking off. But if Stars on Mars is any indication, mission planners have their work cut out for them. Winter went home earlier this month, and on her way out, she said she was glad to have been on the show but also that “it was like a little bit of hell.” When people finally do make it to Mars, we’ll be the aliens, fumbling our way around a world that is not designed to sustain creatures like us. But we’ll still be only human.