On 26 September 1991, eight crew members (four men and four women) were sent to live in Biosphere 2 for two years, completely cut off from the outside world. Biosphere 2, located in Arizona in the US, was the world’s largest artificially enclosed system. The mission was to discover whether a group of humans could live in an isolated colony, like they would on another planet. The 12,000-square-metre structure had its own oxygen system, its own rainforest and its own ocean. The crew produced its own food, recycled waste and water, and conducted research. However, after less than a year, food was getting low and the crew began to argue. In early 1993, oxygen levels in the dome had dipped so low that the crew was struggling to breathe. The medical team was forced to let oxygen into the dome, and open the air locks.
Although the mission lasted a full two years, many people deemed the project a failure because it had to be helped out by the medical team.
The team spent two years in isolation.