For six crew members who were part of an unprecedented NASA study, their year on Mars is finally over.
OK, they were actually on a volcano in Hawaii, not Mars, but their lives for the past year simulated what it would be like to be on the fourth planet.
Apart from the occasional walk over the rocky terrain in a space suit, they were stuck in some really close quarters with five other people for a year. Not the kind of Hawaiian vacation most of us have in mind.
It's called the Hawaii Space Exploration Analog and Simulation. That's its name, anyway. Mostly it's called HI SEAS.
A psychological and emotional test
Solving the technological challenge of flying through space to Mars and surviving on its barren landscape is not the only hurdle involved in visiting the red planet.
There's also the challenge of staying psychologically healthy during such a long strange trip. That's where NASA benefits from the input of Gloria Leon, a University of Minnesota psychology professor emerita who has been consulting with the space agency on astronaut selection since the 1990s.
Astronauts who serve extended tours aboard the International Space Station have provided some of the most useful information about the psychological effects of the isolation of space.
Naturally, astronauts miss their family members but that's not all. The U of M's Leon tells the Christian Science Monitor: “They get to miss the feeling of wind on their faces. They miss the smells of nature, or the smell of food cooking. On a Mars voyage, Earth will be out of view. It will be the equivalent of twilight, looking out of the porthole. So there will be boredom – monotony, really – in terms of the environment.”
The dome's diameter is 36 feet
The crew members emerged on Sunday from a two-story dome that's only 36 feet in diameter. Crammed into that space are a kitchen, dining area, bathroom, bedrooms, a common area, a lab, an exercise area, and a workshop. There's lots of background here about the dome, the crew, and what NASA's been studying.
With daily sunrises and sunsets, the HI SEAS crew did not experience the kind of environmental monotony that Leon mentioned to the Christian Science Monitor.
Nor did they encounter seeing Earth in the context of other heavenly bodies, something that has had a profound impact on some earlier astronauts.
When Edgar Mitchell of the Apollo 14 crew died earlier this year, Motherboard looked back at the epiphany Mitchell had on his trip back to Earth and noted that several astronauts have described a feeling of oneness with the universe after their missions are over.
Leon tells Motherboard she uses the term "universalism" to refer to this change of perception travelers through the cosmos may have after seeing how fragile and small Earth appears from space.
Perhaps it provides a new take on the wind in your face or the smell of bacon. Or the taste of shaved ice.