An Analogy – The International Space Station
Water is equally precious to humans. About 70% of each of our bodies is water. It is the conduit through which we transport in energy and nutrients as well excrete waster. It regulates our body temperature. However after we use water then we can clean it. So on the road to self-sufficiency in space then this possibility may present the greatest opportunity. Current estimates put human usage in space at 11 litres a day per person.
We eat. Most of us really enjoy eating which presents its own problems. People in space will likely never have this concern as they will never have an excess of food. Or at least they won’t until they start producing their own food. Also note that food often includes a lot of liquid so it presents a slight source of water. Current estimates put human consumption at 0.83kg per day per person.
People are used to a certain ability to move. Some in crowded cities are used to and even enjoy continual close contact with thousands of strangers. Others prefer a certain amount of distance, even isolation. While the Moon has a vast surface to wander, it is barren. People will need to stay within a habitable chamber. While the need to move varies for different activities let’s assume that we need a habitable volume 25 cubic metres per person.
Given these requirements then we see the following necessities for our habitat.
|Time||Number of People||Water (l)||Air (kg)||Food (kg)||Habitable Volume (m3)|
|2nd to 5th||6||32142||1000||7276||150|
|6th to 10th||10||80355||2500||18188||250|
|10th to 20th||25||334812||10417||75789||625|
This table shows that our habitat will need significant mass of supplies if its residents remain reliant upon the Earth for all its needs. This confirms our need for the residents to be self-sufficient as soon as possible.