This week 13 people will begin a nine-month mission inside a small, remote station largely cut off from the world. Outside their habitat there is little air, extremely cold temperatures and no sunlight. The crew must eat only what they've stockpiled and recycle their precious water for reuse. Despite appearances, however, these people are not going to space, but to the next best thing: Antarctica.



The European Concordia Research Station is set to begin its 10th winter season on the southernmost continent, where the sun will not rise for more than three months starting around May. In addition to conducting astronomical, atmospheric and glacier research, among other projects, the crew will serve as test subjects on a mock mission to Mars. After all, their experiences are the closest we can come to learning how astronauts will fare on a real long-distance space voyage without actually sending them off Earth. "We’ll never be able to be 100 percent prepared for everything," says Oliver Angerer, project manager for Concordia at the European Space Agency (ESA). "We can only do the best we can by learning as much as we can from similar situations."



Scientists will closely monitor how the Concordia crew members fare physically, mentally and emotionally. "You have limited space for a bunch of people, no contact with the outside world in a normal way, no sunlight or normal circadian triggers," says Peter Gräf, life sciences program manager at the German Aerospace Center, who has worked on numerous Mars analogue missions. "You have a bunch of people you have to get along with, and you have no alternatives and no escapes." Studies will track how their diet and metabolism correlate with mood changes, whether their sleep is disturbed by the lack of sunlight and pressure changes, and how the isolation and stress of the situation affect crew dynamics. All of these data will eventually be used to help plan the first official missions to Mars and other deep-space destinations.



Concordia station, which is jointly operated by the French Polar Institute and the Italian Antarctic Research Program, is just one of several Mars analogue missions undertaken by the world's space agencies and science organizations. In 2010 Russia, the ESA and China collaborated on the Mars 500 mission, which sent six volunteers inside a sealed habitat for 520 days on a mock mission to and from the Red Planet. NASA routinely sends astronauts to the desert as well as deep under the sea on the Aquarius research station to simulate space missions. And the nonprofit Mars Society is planning a yearlong mission simulation at its Flashline Mars Arctic Research Station (FMARS) in northern Canada starting in summer. "By practicing these missions you can find out what technologies you need and what technologies you don’t need," says Mars Society president Robert Zubrin. "You can find out what the real requirements for crew psychology are. And I think these things do one other thing: they focus people's attention on what the space program should be doing." Simulating a mission to Mars, he says, can excite the public and galvanize support for a real journey there.



All of the Mars analogue missions to date have drawbacks. Concordia station, for example, is primarily a scientific research outpost, so its operations do not always match the procedures of a space mission. For instance, there is no mock "mission control" orchestrating from afar, and the mission is not structured around the timeline for a transit to and from Mars. Tailor-made analogue missions such as Mars 500, however, have other downsides. The schedule and operations of that simulation closely adhered to expectations for a real space mission, but it lacked a central element: danger. The trial took place in a mock spacecraft at the Russian Academy of Sciences's Institute for Biomedical Problems in Moscow, so unlike at Concordia station, the participants knew that if something went seriously wrong, the real world was waiting just outside the door. "You have advantages and disadvantages in either setting, and they are complementary," Angerer says. In many ways the International Space Station is the best analogue for the trip to and from Mars. It cannot, however, serve as a test bed for all of the strategies and technologies needed to survive on the Red Planet's surface.



Already analogue missions have taught surprising lessons. During short-term precursors to this summer's FMARS mission, the Mars Society tested out various vehicles that have been proposed to carry astronauts over Martian terrain. Some experts had favored pressurized SUV-like buggies, whereas others advocated for open-air rovers or individual scooters. "For a long time I was behind the SUV type," Zubrin says, "but on the basis of the field work we've done, I'm now a convert to a single-person all-terrain vehicle." Their tests found that pressurizing and depressurizing every time an astronaut wanted to get out of the vehicle was too laborious. A spacesuit-clad astronaut riding a smaller transport had more flexibility. "Before you got to the trouble of spending a billion dollars to develop a rover or all-terrain vehicle that can work on Mars, you need to decide which one is the one you want," Zubrin says. "It's important in engineering to build things right, but it's even more important to build the right things."



Physiological and psychological studies show functioning under the stress and isolation one is likely to encounter on a Mars mission is no easy feat. Four of the six crew members of Mars 500, for example, showed significant adverse reactions. Some lost sleep or the motivation to eat and exercise. Others became depressed and socially isolated. "Those four crew members would not be ideal for a long-duration mission and would potentially be a problem that could create serious consequences," says David Dinges, a psychologist at the University of Pennsylvania Perelman School of Medicine who worked on the Mars 500 experiment and other analogue space missions. Being able to tell ahead of time which crew members are vulnerable to these problems and what personal qualities protect against them is the "holy grail question," he says. "In our lab we search for the biological basis of these differential responses, and try to figure out how to use that knowledge to identify and mitigate the risk."



One upside of spending time away from the everyday routines of Earth can be a newfound appreciation for simple things. Past crews of Concordia station have spoken about seeing the sun for the first time after a dark Antarctic winter. "It's really impressive how they describe the moment when the sun is returning," Angerer says, "what a huge effect it has, basically reconnecting them with everything that is beautiful."

