Six people have shut themselves inside a dome in Hawaii for a year, in the longest US isolation experiment aimed at helping Nasa prepare for a pioneering journey to Mars.
The crew includes a French astrobiologist, a German physicist and four Americans - a pilot, an architect, a doctor/journalist and a soil scientist.
They are based on a barren, northern slope of Mauna Loa, living inside a dome 11m across and 6m tall.
The men and women have their own small rooms, with space for a cot and desk, and will spend their days eating foods like powdered cheese and canned tuna, only going outside if dressed in a spacesuit, and having limited access to the internet.
Crew member Sheyna Gifford described the team as "six people who want to change the world by making it possible for people to leave it at will," she wrote on her blog, LivefromMars.life.
Nasa's technology can send a robotic mission to the Red Planet in eight months, and the space agency estimates a human mission would take between one and three years.
With all that time spent in a cramped space without access to fresh air, food, or privacy, conflicts are certain to occur. The US space agency is studying how these scenarios play out on Earth before pressing on to Mars, which Nasa hopes to reach in the 2030s.
The first experiment involved studies about cooking on Mars, and was followed by a four-month and an eight-month co-habitation mission.
Nasa is spending US$1.2 million ($1.85 million) on these simulations, plus another $1m for three more in the coming years according to principal investigator Kim Binsted.
Binsted said conflicts arose during the eight-month mission but the crew was able to work through them.
- AAP