In the early 1990s, a set of enclosed biomes and living spaces in the Arizona desert, called Biosphere 2, housed four men and four women. The goal was to to see how humans might survive in outer space. The group lived inside for two years and attempted to be fully self-sustaining.
Over the course of that experiment, however, food became scarce and oxygen levels in the community dropped (partly because organic matter in the soil promoted the growth of oxygen-hungry bacteria). By the end, the residents had divided into factions and some were barely on speaking terms.
Belvisi told Venture Beat she has spoken with the experiment's alumni to learn how to avoid these issues.