This is what we knew about the moon already. The moon goes around the earth about once every 28 days, and a lunar day is also 28 (earth) days long. That means that the sun is in the sky for two whole weeks, then the lunar daytime is followed by two weeks of lunar nighttime. With all that sunlight, it gets really hot during the lunar day (about 250° F/121° C), and it gets really cold during the lunar night (about -250° F/-156° C). There is only the tiniest, tiniest bit of an atmosphere on the moon, but it's so thin, most people would say there's no atmosphere there at all. It's too thin to breathe, airplanes won't work in it, parachutes won't work in it, meteors and rockets won't slow down in it, and there are no clouds or weather in it. The dirt on the moon is a mix of rocks and a lot of really fine dust, and it's made of almost the same chemicals as dirt on Earth. The moon's gravity is 1/6th as strong as earth's gravity. If you can jump two feet (0.6 meters) high on earth, you'ld be able to jump about 12 feet (3.6 meters) high on the moon!
Even though we only knew a little about the moon, we knew a whole lot about being rodents. We live in the same kind of an environment that people do: we need fresh air and water, and the temperature can't be too hot or too cold -- around room temperature (68° F/20° C) is about the best. We like to eat mostly plants and grains. We don't need quite as much water as people do, but we still need enough to drink. Here's what NASA decided a grown person needed each day to breathe, eat, drink, and stay clean and healthy on a Space Station:
Oxygen 0.83 kg
Food (dry) 0.62 kg
- water in food 1.15 kg
Drinking Water 1.61 kg
Cooking Water 0.79 kg
Water for washing 25.52 kg
Water for the toilet 0.49 kg
Every person also creates a bunch of waste that has to be taken care of. Here's NASA's table of how much waste a person would create each day on a space station:
Carbon Dioxide 1.00 kg
Water from Sweat
and breathing 2.28 kg
Water from Urine, etc. 1.59 kg
Water from cooking 0.04 kg
Water from washing 25.53 kg
Water for the toilet 0.49 kg
Waste Solids 0.11 kg
Since a moonbase is pretty much like a space station, we figured that these numbers were about right, or at least they were a pretty good guess for what we would need.
But before long we noticed we had several really big problems we had to figure out. Every day, we were going to use up a lot of oxygen and create a lot of carbon dioxide from our breathing. Also, we were going to use up a lot of water, and create a lot of urine and other waste. How were we going to permanently live on the moon with all this waste, and no air outside? Not only that, every month the outside temperature was hotter than boiling water for two weeks, then so cold your whiskers would crack off for the next two weeks. These were some pretty big problems all right...
How were we going to solve them?