Remember Biosphere 2?

Remember back in 1991, when a colony of eight people set about to live inside a sealed environment for two years?

Scientists interested in space travel and the possibility of colonizing the Moon or Mars sealed people inside the structure, hoping to learn what problems would arise from living in a closed system.

The site of this experiment, Biosphere 2, is located about 30 miles north of Tucson. We began our tour by passing through The Village, living quarters for present-day conference attendees.

Built in the late 1980s in the foothills of Arizona's Santa Catalina Mountains with $150 million in funding from Texas oil magnate Edward Bass, Biosphere 2 was designed as an airtight replica of Earth's environment (Biosphere 1).

The 7,200,000-cubic-foot sealed glass and space-frame structure was home for 24 months for the first crew of Biospherians (4 women and 4 men) who entered Biosphere 2 on September 26, 1991. All had spent several years in training to become more proficient in their own fields as well as gaining expertise in the skills of the others.

The facility covers a little over three acres and the glass-enclosed structure is 91 feet at its highest point. The ecological systems of Biosphere 2 include agriculture, a human habitat, an ocean (photo # 3 below), a tropical rainforest (photo # 4 below), a savannah, a marsh, and a desert (photo # 5 below). Each different system was built with soils, water, plant, and animal life collected from all over the world. Biosphere 2 sustains approximately 3,800 living species within its glass walls.

The buildings in the center of this photo were the housing units and work areas for the participants. On the far right is one of the two domed buildings that house the "lungs" of the Biosphere 2 (more later).

The crew members remained inside for two years, emerging on September 26, 1993, setting a new world record for living in a closed system.

The crew members lost an average of 16% of their pre-entry body weight before stabilizing. Their health continued to be excellent, due in large part to their low-calorie, low-fat, nutrient-rich diet.

The leader of our tour mentioned that some disagreements among the eight members led to the formation of two groups of four each during the course of the two years. The psychological effects of this type of living condition has led to increased study of this phenomenon.

The development of a sustainable, highly productive, and non-polluting agriculture system was clearly one of the top achievements of Biosphere 2. Eight humans were fed from half an acre. The crew had produced approximately 80% of their food with the other 20% being drawn from a three-month supply of food that was grown inside the facility before the experiment began and from seed reserve.

The chemical-free system recycled all human and domestic animal waste products and utilized dozens of crop varieties to provide nutritional balance and allow for crop rotation.

One of the few medical problems was related to altitude sickness due to an unpredicted decline in the atmosphere's oxygen content. The low oxygen concentration - at its lowest point, equivalent to the oxygen concentration at about 9,500 above sea level - caused some crew members to experience fatigue, disrupted sleep, and shortness of breath.

We thought the most interesting part of the tour related to the engineering components of Biosphere 2. In their world, the Biospherians managed and controlled every system from waves, tides, waterfalls and currents to rain, temperatures and humidity. This photo shows a small portion of these controls.

Because Biosphere 2 is air-tight and covered with glass, sunlight heating the air inside would cause the air to expand and cause the glass to explode; conversely, prolonged cooling could cause the glass to implode. Two "lungs" serve as variable volume chambers--able to expand or contract in response to temperature changes that affect the air volume within Biosphere 2. As pressure from the heated air increases during the day, the disc suspended by a rubberlike substance (the black area in the left of the photo) rises. As the pressure decreases from cooling at night, the aluminum disc descends. In this way, the disc functions as a lung.

Since a second crew of seven biospherians had their isolation suspended in 1994 before completion, there have been no resident crews living inside Biosphere 2, and no future human habitation is planned.