Plants, Animals, Food, Oxygen, and Carbon Dioxide
The trick to living in space is to live there with some of your plant friends. You probably already know that animals breathe in oxygen and breathe out carbon dioxide. When plants are in sunlight, they 'breathe' in carbon dioxide and breathe out oxygen. So plants and animals help each other survive by using each other's 'waste' air. If your space habitat has the right number of animals or people and the right number of plants, then the air stays fresh and healthy for everybody. You could say this is how we 'recycle' air on the moon base.
The other very important thing plants give animals is food. Scientists at NASA have tested many different types of food plants to help people breathe and eat in space, and they have even developed special plants that make a lot of oxygen, but we still need a lot of plants to keep a human being alive in space (about 40 square meters of garden would supply the food and air needed for each person on the moon -- this is about half the area that a house sits on if laid flat, but in space the garden is built on many shelves like a very big bookcase, so it takes up a lot less room).
Plants still need a lot of help to grow. They need water, just
like us, and they also need a lot of light. One tricky thing about
plants is that they don't make oxygen for us if they're in the dark, so
we would have a very hard time breathing during the two week long lunar
night if we didn't have bright lights pointed on the plants. During
the two week long lunar day, there will be plenty of light to help out
the plants. Water is a little tricky too. Some of the water
we use for washing can be used on the plants as is. Other forms of
water get processed a little differently.
Where do we get our drinking water?
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Speaking of water, where do you think we could get the water we drink? You may be surprised to find out that we can get it out of the air! All living animals transpire (breathe out humid air) and perspire (sweat, which evaporates), and all living plants transpire through microscopic holes in their leaves. All that transpiring, perspiring, and evaporating puts a lot of water vapor into the air. If that air is blown across a cold pipe, water condenses out of the air onto the pipe. This is the same thing that happens in the summertime when you get a cold glass of soda or lemonade, and water condenses on the outside of the glass. So we have machines on the moon (kind of like air conditioners) which have cold tubes in them that air is blown across. Water forms on the outside of the tubes, and that water drips into a container for us to use for drinking and also watering plants. Using this machine is one way we 'recycle' our water on the moon base. |
What do we do with our trash (etc)?
There is one thing that is very different about living on the moon than
from living on Earth. That is, trash, sewage, and toilet water can't
be thrown out. This is because that stuff contains extremely valuable
nutrients for plants as well as that very precious substance water.
Special machines called bio-reactors use bacteria to break down the solids
in the trash and sewage into their basic nutrients. This also gets
rid of a lot of unfriendly germs as well. This works kind of like
the compost heap you may have in your garden. After the bacteria
are done with the trash, the remaining nutrient soup can be given to the
plants to help them grow. This way we 'recycle' our trash and sewage
on the moonbase.
Recycling is the Key
Did you notice how air, water, food, and waste all gets recycled on the moonbase? That's the most important key to living permanently on places like the moon and Mars. This is also true on Earth, but on Earth there is already a complex ecosystem filled with plants, animals, and bacteria, that takes care of all of the recycling for all of Earth's inhabitants. On the moon and Mars, you sort of have to build that ecosystem from scratch.