The South Pole Greenhouse is an enigma. Here we are, at the bottom of the world, surrounded on all sides by a frozen ocean of ice, an environment that is inhospitable and hostile in every respect, basically the last place on Earth where you would expect to find anything growing. Yet here it is, a botanical oasis in the middle of the icy desert.
Aside from us humans and the occasional bug brought in with the weekly fresh food delivery, the plants growing in the greenhouse are the only living things within hundreds of miles (not counting the gazillions of microbes and bacteria that we brought with us, that is. Oh, and there are a few microbes outside too, blown in with the wind, but they don’t really constitute an ecosystem per se). None the less, the point I am trying to make is that the fact that we as humans have developed to a level of sophistication capable of artificially creating a living and growing ecosystem, in a place that to all degrees we have a hard time surviving, is in my opinion, nothing short of a miracle.
The implications of this achievement, while subtle, are significant: if we as humans ever have a hope of serious space exploration, our ability to bring a little piece of living “earth” with us will be paramount to our success- not only to keep everyone on the space ship sane, but to recycle their waste, to convert the limited supply of air back into oxygen, and of course, to provide food. The South Pole Greenhouse does a good job with two of these needs- keeping people from going crazy, and supplying tasty things to eat, but as far as the others go, we are still on Earth, so there is no worry about lack of oxygen, and our waste is just pumped into a giant hole in the ice, so no need to muck around with it trying to fertilize plants. That being said, the greenhouse could perform these other two tasks with a few extra pieces of equipment and were it many more times larger than it is.
It turns out that to supply enough oxygen for one human to breathe takes about 50 square meters of growing plants, and to provide a sufficient amount of food takes about 100 m2. As it is, our greenhouse is nowhere close to these proportions, only being about the size of a small garage. Even so, the greenhouse control system monitors all the essential variables such as O2 and CO2 levels, humidity, pressure, evaporation, power usage by the UV lamps, and pH and nitrate levels in the water (the plants are all grown via hydroponics, being that the Antarctic Treaty prohibits bringing foreign soil to the Pole), and everything is maintained at a precise equilibrium to provide supreme growing conditions for the plants. Scale this system up by a factor of 40 or 50, and you could easily imagine a giant greenhouse on the Moon or Mars, supplying all the needs for a base of happy, vegetarian astronauts.
Being limited in size, the greenhouse only grows about 25 or 30 different varieties of plants, from peppers to cucumbers and lettuce to sunflowers- there is even a watermelon growing nice and plump, probably to be served at the Mid-winter Dinner Party held in the middle of June. Mostly though, lettuce and leafy greens are the main produce coming out of the greenhouse. Fresh salads are a luxury at the Pole- even in the summer when other fresh fruits and veggies are flown in, lettuce never makes the cut because it would go bad before it reached us. But even though we grow it on station, our nice green salads come at a price. Consider all the inefficiencies in the process: flying in the fuel to run the power plant; generating the electricity to power the UV lamps; converting the electricity into light, most of which misses any plant material, hitting the greenhouse walls or floor instead; of the light that does hit a plant’s leaf, only about 4% of it is converted into energy that the plant can use to grow; and only a proportion of that energy is used to grow the edible fruit or leaf that we are interested in. All told, a tasty little green salad grown at the South Pole costs roughly $50 a pound! Now, that does seem like a lot, and not being the biggest salad fan, I am inclined to say that it is not worth it. But I am a fan, a big fan, of the idea of exploring space, and if a $50 dollar salad is what it takes to get us there, then I say “Can you pass me the dressing?”