Red sand shifts under the boots of the crew members. In the distance, it appears that a rocky mountain range is rising out of the Martian horizon. A thin layer of red dust coats the solar panels and equipment necessary for the year-long mission. This landscape isn’t actually 145m miles away. We are in a corner of the Nasa Johnson Space Center in Houston, in a large white warehouse right next to the disc golf course and on the tram route for tourists and school groups. But starting this June, four volunteer test subjects will spend a year locked inside, pretending to live on Mars. Nasa researchers say they’re doing everything they can to make it as realistic as possible so they can learn the impact that a year in isolation with limited resources has on human health. “As we move from low Earth orbit, from moon to Mars, we’re going to have a lot more resource restrictions than we have on the International Space Station and we’re going to be a lot further from Earth or any help from Earth,” said Dr Grace Douglas, the principal investigator for the Crew Health Performance Exploration Analog, or Chapea for short. The four crew members will live in a small housing unit that was constructed using a huge 3D printer to simulate how Nasa may create structures on the Martian surface with Martian soil. They’ll conduct experiments, grow food and exercise – and be tested regularly so scientists can learn what a year on Mars could do to the body and mind. “This is really an extreme circumstance,” said Dr Suzanne Bell, who leads the Behavioral Health and Performance Laboratory at the Nasa Johnson Space Center. “You’re asking for individuals to live and work together for over a one-year period. Not only will they have to get along well, but they’ll also have to perform well together.” Watching four people spend a year in a 3D-printed box is Nasa’s next small step toward landing humans on the surface of Mars. Nasa says it hopes to send humans to the red planet as early as the 2030s. The first mission could be a nine-month trip one-way, and could leave the astronauts on the surface for two and a half years before starting the long trip back home. Preparations for that trek are already well under way with the agency’s Artemis program. Artemis is sending astronauts back to the Moon for the first time since 1972, including the first person of color and woman to walk on another celestial body. As part of the Artemis missions, Nasa is also launching Gateway, a space station that will orbit the Moon and serve as a pit stop for Mars-bound missions. Getting to the Moon means getting to Mars, and getting to Mars means testing the physical and behavioral health of a crew in isolation. That’s where Chapea comes in. The mission isn’t Nasa’s first test at long-term trial runs before sending humans deeper into space. In 2015, astronaut Scott Kelly and cosmonaut Mikhail Kornienko spent a year on the International Space Station. Scientists compared Kelly’s biometrics with his Earth-bound identical twin, Senator Mark Kelly, to learn the effects of extended spaceflight. Nasa’s scientists are also conducting a series of “analog missions” meant to simulate various parts of space exploration here on the ground. “No matter how challenging or large or expensive something like this is, it’s easier than doing it in spaceflight,” said Scott Smith, who leads the Nutritional Biochemistry Laboratory at Nasa Johnson Space Center. “So when we want to look at bone loss and muscle loss, we put people to bed. When we want to look at vitamin D and people that don’t see the sun, we go to Antarctica. When we look at oxidative stress, we go to the bottom of the ocean. And when we want to look at closed environments and stress, we build chambers like this.” Nasa hasn’t identified the four crew members set to enter the habitat in June, but said they were selected using similar criteria to the astronaut corps. They are people with advanced degrees in Stem fields (Science, Technology, Engineering, Maths) and fit a physical and psychological profile to make them suited for such an experiment. The 1,700 sq ft home for the next year includes four private quarters and a shared bathroom with a shower and toilet. There are dedicated workstations, a medical station and lounge area – complete with board games like Settlers of Catan: Starfarers edition and Monopoly, and a Play Station 3 and Super Nintendo console. Using indoor greenhouses, the crew members will grow ready-to-eat food like tomatoes and leafy greens, which will also let Nasa evaluate the quality and efficacy of its plan to grow crops on Mars. Their trash will be analyzed by Nasa scientists working to design products that can be reused in space. There will even be a 22-minute communication delay between the Chapea inhabitants and the outside world, just like astronauts will experience when communicating with Earth. “The whole experience is impacting the human, and what we’re looking at is the response to the human,” Smith said. “All that will likely show up in the data we’re collecting.” The most striking feature in the Chapea habitat is the 1,200-sq ft sandbox outside. The crew will don pseudo space suits and go through a fake airlock to enter the “outdoor” portion of the habitat – an inflatable bubble filled with sand and a simulated Martian landscape. It’s here that the participants will complete simulated missions – Nasa’s calling them “Marswalks” – which will be completed in pairs, complete with virtual-reality technology to make it seem like they’re actually traversing the red planet’s surface. Some of those traverses will use basic geology skills – identifying rocks of interest, photographing them and bringing a sample inside for analysis – or site evaluation skills for possible construction of other structures as our footprint on Mars expands. Other missions will involve maintenance to the Chapea structure or dusting sand off of the habitat’s outdoor solar panels. Using treadmills and the VR simulations, they could hike for hours, like real astronauts may need to, to conduct research and gather resources on Mars. But Nasa won’t just be collecting data from the experiments conducted by the Chapea participants, they’ll also be monitored closely for signs of physical and mental stress. Nasa says it wants to make the experiment as Mars-like as possible, which means not just isolation, but extra manufactured stressors like resource limitation, equipment failure and heavy workloads. The crew members will have a limited food supply, for example, and will need to allocate resources carefully. They’ll need to submit regular blood samples and conduct psychological surveys. “We are very interested in the stress response to a situation like that, particularly in that long-term isolation and confinement,” Bell said. “We don’t have a lot of data about what happens to someone in isolation for a year.” Douglas said the participants are allowed to leave the habitat and the experiment if they wish and two alternates have also been selected just in case. “We’ve set the team up for success,” Bell said, “but we still need that data before we actually send people to Mars.”