Nothing green grows, and all you can see for miles are chunks of red rock and endless fields of lava tubes. It's easy to imagine you're on another world.

But it's even easier when you spot the 1,200-square-foot dome that sits near the summit, which looks exactly like the kind of space habitat that astronauts would use as a base camp on the red planet.

Researchers created this dome to lock volunteers inside and study the least-understood challenge that people will face on a real Mars mission, whether or not SpaceX or NASA sends them: Total isolation.

Volunteers are cooped up together for the better part of a year. Back in civilization, scientists monitor and measure their performance and see how well they work together as a team.