The project conducted two sealed missions; the first from 1991 September 26 to 1993 September 26, and the second for six months in 1994. During the first mission, oxygen and carbon dioxide fell. Oxygen and other supplies were provided, and the project lost some credibility.
In 1995 the Biosphere 2 owners transferred management to Columbia University. Since 1996, over 1200 graduate students have spent a year in the Biosphere 2 Center (as of 2003). The site has its own hotel and conference center.
Science and engineering
The scientific method is difficult to apply due to the complexity of the biosphere and the absence of a control. Like the Apollo program, Biosphere 2 is an achievement of engineering rather than science.
Difficulty of creating successful artificial biospheres
An interesting consequence of the experiment is that it showed the difficulty of copying the functions of the natural capital of the evolved Earth biosphere with infrastructural capital constructed by humans with present technology. Despite expenditure of over $150 million, this attempt at a new biosphere did not sustain eight humans, for a limited time, while the original sustains billions of humans, and shows little sign of failing any time soon.
Value of Earth's biosphere
Some economists have used the price of the Biosphere 2 project as an input to value of life calculations, and attempts to calculate the total value of all natural capital on Earth. According to them: given that it does at least as good a job at sustaining humans as Biosphere 2, it should be worth at least as much per resident. This leads to a rather large, but finite, price of Earth itself.
Other artificial biospheres
See also: biological engineering, Controlled Ecological Life Support System, ecological engineering, life support (environment)