page_title: Biosphere 2
section_title: Engineering
hierarchical_section_title: Biosphere 2 / Engineering
caption_attribution_description: Biosphere 2 from the inside, half the original size.
context_page_description: Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. It was originally constructed between 1987 and 1991, and has been owned by the University of Arizona since 2011. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the universe. It is a 3.14-acre structure originally built to be an artificial, materially closed ecological system, or vivarium. It remains the largest closed system ever created.
  Biosphere 2 was originally meant to demonstrate the viability of closed ecological systems to support and maintain human life in Outer Space. It was designed to explore the web of interactions within life systems in a structure with different areas based on various biological biomes. In addition to the several biomes and living quarters for people, there was an agricultural area and work space to study the interactions between humans, farming, technology and the rest of nature as a new kind of laboratory for the study of the global ecology. Its mission was a two-year closure experiment with a crew of eight humans.
context_section_description: The above-ground physical structure of Biosphere 2 was made of steel tubing and high-performance glass and steel frames. The frame and glazing materials were designed and made to specification by a firm run by a one-time associate of Buckminster Fuller, Peter Jon Pearce (Pearce Structures, Inc.). The window seals and structures had to be designed to be almost perfectly airtight, such that the air exchange would be extremely low, permitting tracking of subtle changes over time. The patented airtight sealing methods, developed by Pearce and William Dempster, achieved a leak rate of less than 10% per year. Without such tight closure, the slow decline of oxygen which occurred at a rate of less than ​¹⁄₄% per month during the first two-year closure experiment might not have been observed.
  During the day, the heat from the sun caused the air inside to expand and during the night it cooled and contracted. To avoid having to deal with the huge forces that maintaining a constant volume would create, the structure had large diaphragms kept in domes called "lungs" or variable volume structures.
  Since opening a window was not an option, the structure also required a sophisticated system to regulate temperatures within desired parameters, which varied for the different biomic areas. Though cooling was the largest energy need, heating had to be supplied in the winter and closed loop pipes and air handlers were key parts of the energy system. An energy center on site provided electricity and heated and cooled water, employing natural gas and backup generators, ammonia chillers and water cooling towers.
caption: Biosphere 2, viewed from the thornscrub, a transition zone between Savannah and Desert (foreground) and Ocean (background) sections
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