Inspiring the world.

Biosphere 2 becomes ‘big science’

As you approach the turnoff for Biosphere Road, 30 miles north of Tucson on State Highway 77, you see nothing but the Sonoran Desert of southern Arizona and a couple of semi-civilization knickknacks. There is a rock with the Biosphere 2 logo on it. There is a flagpole. At the flagpole, in order from top to bottom, wave (1) that star-studded banner that the current administration in Washington detests so much, (2) the starburst of the copper state of Arizona, and finally the University of Arizona “A” flag.

Turn right (if heading north). Spend a couple of miles past cattle crossings, a copper mine, an electrical substation that has nothing to do with B2, and an empty guard post at the entrance to what was once Sunspace Ranch. As you walk in, you might catch a glimpse of what Columbia University called “The Apparatus” when they ran the place. It ends in a tree-lined parking lot next to an entrance plaza equipped with fabric awnings. Watch for snakes.

Just to get it out of the way, note that Biosphere 2 offers “under glass” tours inside the 3.14-acre biosphere apparatus (the U of A likes to call it “The Sphere”) from 9 a.m. to 4 p.m. 363 days a year except Thanksgiving and Christmas Day, which they call “December 25.” They do tours even though it snows a little. (Biosphere 2 is 3,900 feet above mean sea level, 1,400 feet above downtown Tucson.) They do so even if the summer monsoons are wreaking havoc in the foothills of Catalina Mountain, where the Biosphere is located, as long as it is deemed safe. For ticket prices (around $20), you will have called 520-838-6200. The voice is automated, so you will NOT find out this way that you can get a better deal with membership, as revealed by the B2Science website. See “Links” at the end of the article.

The website also explains why people with physical limitations may not be able to take the tour. Stairs are unavoidable. The balance can be uncertain. You have to watch your head. You have to watch your step. You have to see both at the same time.

Well, it can’t be that bad. Over 100,000 visitors a year come this way, from 100 a day or less in the summer months, when tours run 1 hour and 15 minutes apart, to 900 a day in the winter, when tours start every 15 minutes. Add in the ten minutes or so it takes to get to the starting point, and you should allocate 90 minutes to the tour, not counting bathroom breaks, shuffling through underwater caves to see the man-made ocean floor , or visiting what was the human habitat when Biosphere 2 was the home of the “biospherians”. Fifteen biospheres on two “missions” lived there in simulated space colony conditions from 1991 to 1994. There is a souvenir shop. There is a “café”, but its offer is limited, as are its hours. If you’re not in a hurry, Biosphere 2 is good for 2.5 hours.

You start the tour with a 10 minute movie. Make a main call if you don’t care about the party line, because it’s all about political imagery. It indicates to the viewer that the “Sphere” is the only place where certain experiments can be performed, and therefore the U of A must control the Sphere, or the world will end. You will hear that over and over again, throughout the tour. If you question the concept, you’ll hear it again, along with the words “I said that”, so don’t torture the tour guide.

Look out for signs posted everywhere proclaiming that the Biosphere is now, thanks to the University of Arizona, “Great Science.”

Be that as it may, Biosphere 2 is a feat of engineering. That becomes clear as your guide points out construction details, such as the triple-pane hermetically sealed glass and steel structure, the cave-like air registers and massive returns, the network of rain pipes on the top and the Artificial Ocean Wave Machine. The tour will include a passage through the “Technosphere”, domain of air handlers, coolers, pumps, tanks, reverse osmosis filters, circuits and pipes. Above, you may have noticed that the rainforest might be running at 120 degrees Fahrenheit with 90% relative humidity, while the coastal desert is 85 degrees with 25% humidity. Each biome has its own independent environmental control system in the Technosphere.

Although the temperature inside the glass should vary with the time of day and season to mimic that of the Earth, it is essential that the pressure variation inside the glass does not exceed the strength limits of the glass (Charles Law, people, chemistry high school). The problem is solved by the use of two dome-covered “lung” structures to the south and west of the main Biosphere. Inside each protective white dome, there is a cylinder covered by a rubber diaphragm (Hypalon) that lifts a central weight. Both the diaphragm and the disc-shaped weight form the roof of the wide cylinder connected to the biosphere by a tunnel. The weight controls the pressure and the diaphragm moves up or down like a piston to convert what would otherwise be a change in pressure into a change in volume as it rises and falls throughout the day (Boyle’s Law). Your tour will visit the southern lung, with its added feature of a 250,000-gallon reservoir to collect “rainwater” for recycling. With a pair of massive pumps visible above the central pool on the floor, the depot also provides firefighting service for the Biosphere.

As you exit the southern lung to the outside world, hold on to your hat. A fierce wind will blow you out when you cross the hatch. That wind will provide your best evidence of positive air pressure within the biosphere.

Later, as you tour the habitat dwellings on your own, be sure to visit the bathroom. You will find the usual toilet paper in a roll, but it will be in an awkward place, as if the bathroom was not designed to contain it. it wasn’t. Note the hose and valve on the wall. It’s a bidet. Biospherians never used toilet paper. The sewage treatment plant was, well, plants, in the saltwater marsh. Everything, including the sewage, was recycled for closed-loop life support. Today, of course, the bathroom is connected to a standard septic system. That will be your best evidence that Biosphere 2 is no longer closed to the outside.

In fact, Biosphere 2 has been reconfigured to allow certain gases (mainly carbon dioxide) to enter and exit. By this method, the composition of its atmosphere can be precisely controlled, as is necessary to do the kind of science that is done there now. The water is no longer completely recycled. If it were, the isotopic markers used to identify the drainage source would be counted twice.

Biosphere 2 is an ecology laboratory, but its appearance and setting preserve the romance of its story in a place that, at times, evokes the magnificent desolation of the Red Planet. Only the most passionate and emptied visitors buy the “Big Science” story. Seriously, they’re going to Mars.


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