Biosphere 2 is a 3.14-acre closed ecological system research facility in Oracle, Arizona, built between 1987 and 1991 to study whether sealed environments could support human life in space. It contains seven distinct biomes plus agricultural and living areas, and has been used twice for full closure experiments (1991-1993 and 1994), though both encountered challenges with food, oxygen, and crew dynamics. Now managed by the University of Arizona since 2007, it continues research while serving as a public educational facility.