Air Is Pumped Into Biosphere; Dome Has Leaks, Operators Say

Outside air has been pumped into Biosphere II to compensate for leakage, operators acknowledged Thursday, but they denied that it violates their goal of creating a sealed, self-sustaining world.

About 600,000 cubic feet of air was pumped in Dec. 9, amounting to about 10% of the air in the glass-enclosed world, said Bill Dempster of Space Biospheres Ventures. Eight people went into the project Sept. 26 and plan to remain sealed inside for two years.

Dempster, director of systems engineering, said the intent was to replace air that had leaked out and not to deal with a rising carbon dioxide level that critics say endangers the private experiment.

“This is not even approximately that large a breath. This is like a little sip if you will,” he said.

The $150-million experiment calls for the crew of four men and four women to live inside the 3.15-acre domed complex with 3,800 species of plants. They are to grow all their own food and recycle air, water and wastes in what is portrayed as a prototype space colony.

In a telephone interview, Dempster said pumping in outside air does not invalidate the experiment. He said Biosphere’s biological systems are effectively isolated.

“It’s only a matter of degree. It’s impossible to build anything that is perfect in this regard, and so there’s always going to be some degree to which the perfection is not met,” Dempster said.

Within a month after the doors were sealed, the carbon dioxide level began to rise. Project directors say the increase was expected, and tourists who pay $9.95 to visit the dome in the desert northwest of Tucson are told it will be dealt with largely by natural systems.