Six scientists tasked with simulating life on Mars emerged on Saturday after eight months living under a dome located 8,000 feet above sea level in a dormant Hawaii volcano.

The six were part of a human performance study funded by NASA and had not left the dome without a spacesuit on since entering the study almost a year ago. Operating in complete isolation, the scientists were monitored by surveillance cameras, body-movement trackers and electronic surveys to track how they worked as a team.

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“Astronauts are very stoic people, very level-headed, and there’s a certain hesitancy to report problems,” University of Hawaii professor Kim Binsted, principal investigator for the study, told the AP. “So this is a way for people on the ground to detect cohesion-related problems before they become a real issue.”

To release stress, the crew members could use a treadmill or stationary bike–only on sunny afternoons, however, because both were solar powered. Their diet consisted mainly of freeze-dried chili.

Mauna Loa was a prime site for the study because of its terrain and silence. When looking out the dome’s porthole windows, the scientists could only see lava fields and mountains.

[AP]

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