Oxygen

One of the things we'll need when we go to Mars I think: Oxygen. Back in 1991 a company called Paragon set up a biosphere in the Arizona desert. The idea was to put 8 people in there and see if they could live there for 2 years without contact from the outside world, it was a space colony on earth. As usual the media ridiculed them and some pretty funny movies were made, but the experiment was pretty valid.

Once there, on Mars, or where ever, you don't get to call on the cell and say hey bring me some lima beans, we're all out. You make do, or you die, sort of like sailing the ocean in the 1500s. No one will come to rescue you. So understanding the basic needs is pretty important.

As it turns out oxygen was the problem. For some reason, about 16 months in, the oxygen began to falter, and thin. People inside suffered sleep disorders and hallucinations. They eventually had to pump more oxygen into the biosphere.

The experiment was successful as it pointed out a very basic problem that can afflict such a colony. If something goes wrong with the air . . . well, you won't have to worry about the water.