AZ Trip #34: The Giant Lung and more Underneath Biosphere 2

The Giant "Lung" underneath the Biosphere

Last week I toured you through the biosphere in the Arizona desert. Today, we'll take you to the underground part of the biosphere, where you'll learn about the famous giant "Lung" and the oxygen challenge...
Read on! 

Rob and Dan descending into the Biosphere's "Lung"

WHAT IS THE BIOSPHERE 2? As a reminder, here's the summary of the biosphere: 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. ... Its mission was a two-year closure experiment with a crew of eight humans ("biospherians"). The self-contained and sustainable environment (that would simulate what it's like living on another planet in a domed in environment.

Outside look that the windows and steel construction

WHAT'S UNDERGROUND? - Below ground was an extensive part of the technical infrastructure. Heating and cooling water circulated through independent piping systems and passive solar input through the glass space frame panels covering most of the facility, and electrical power was supplied into Biosphere 2 from an onsite natural gas energy center.

Outside another part of the Biosphere - Many windows! 

THE GIANT "LUNG" - 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.  LOOKS LIKE A TRAMPOLINE - The lung resembles a giant trampoline and it rises and descends based on the temperature and air pressure inside the Biosphere 2 environment above. It's fascinating to see. 

The Santa Catalina Mountains

Rob and Dan leaving Biosphere 2

THE OXYGEN CHALLENGE -  There were several challenges to maintaining it as a habitable environment, and that included oxygen and CO2 levels. The oxygen inside the facility, which began at 20.9%, fell at a steady pace and after 16 months was down to 14.5%. This is equivalent to the oxygen availability at an elevation of 4,080 meters (13,390 ft). Since some biospherians were starting to have symptoms like sleep apnea and fatigue, Walford and the medical team decided to boost oxygen with injections in January and August 1993. The oxygen decline and minimal response of the crew indicated that changes in air pressure are what trigger human adaptation responses.

WHERE IS IT LOCATED? The glass and spaceframe facility is located in Oracle, Arizona at the base of the Santa Catalina Mountains, about 50 minutes north of Tucson. Its elevation is around 4,000 feet (1,200 m) above sea level. 

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