During the 1980s an experiment was created outside the community of Oracle, just north of Tucson. The experiment was to create a totally enclosed biosphere ecosystem whereby humans could exist within a structure on any planet without oxygen. Called Biosphere 2 for the experiment, scientists created an environment whereby humans could exist for unlimited amount of time within the ecosystem with everything they required to sustain life. Eight scientists existed within Biosphere 2 for approximately two years. According to Wikipedia, the biosphere tests the “viability of closed ecological systems to support and maintain human life in outer space as a substitute for Earth’s biosphere. It was named “Biosphere 2” because it was meant to be the second fully self-sufficient biosphere, after the Earth itself (“Biosphere 1.”)
I lived in Tucson during this experiment. It turned out to be a failure. Factions developed amongst the scientists, and a power struggle began, particularly when it was discovered during the first year of no contact outside the ecosystem that one of the scientists had left the system to secure a hamburger. Undoubtedly the reduced oxygen and the calorie-restricted, nutrient-dense diet contributed to low morale. ... A faction feared that another faction were prepared to go so far as to import food if it meant making them fitter to carry out research projects. They considered that would be a project failure by definition.