joaquin ruiz is the director of biosphere two. - [justin] it alst reminds me of like a palace. (laughs) not like a laboratory or research environment, but more like a science palace. can you tell us about what's going on here in high level? - sure. right in front of us is the rainforest, you have a big ocean and then you have a desert. - [narrator] it was an audacious idea. build a small scale version of earth, in completely closed quarters. in a matter of years, they recreated a wide array of ecosystems that originalltook billions of years on earth to evolve. to succeed, biosphere 2 needed to be completely self-contained and sealed off with nothing brought in or taken out. - [biosphere volunteer] we have to recycle the nutrients. we're recycling our water, our air. we're recycling everythi. - [narrator] in 1991, 8 volunteers of biospherians lived inside biosphere 2 for two full years. like a future habitat on mars, biosphere 2 had to be perfectly thought out and highly engineered. the health and safety of future explorers depended on its success. any habitat on mars would need