>Materials that we take for granted, like hydrocarbons and plastics, are unobtainable off-earth. Yes, plastics are useful, but they're not a necessity for very

>Materials that we take for granted, like hydrocarbons and plastics, are unobtainable off-earth. Yes, plastics are useful, but they're not a necessity for very many things. They were invented in the past century. In the short term, many things are unobtainable, but longer term, space contains a hell of a lot of material in a large variety. If there's a reason to figure out ways of doing things in space, we will figure them out. >More seriously, the moon and Mars have almost no native sources of energy. Solar cells work well in space for small needs, and fission provides great fuel energy density for larger needs. Both of these work fine in an environment bereft of oxygen. There's no reason they couldn't be self-sustaining long-term.