Eric Watt Forste wrote:
> Ask the cosmonauts how they and everything they were living among
> smelled after the end of a long stay in Mir. (If you can't find a
> cosmonaut, ask a sailor who has done a long tour of duty on a
> nuclear submarine.) Foul air is an unsolved problem for long-term
> missions. Biosphere 2 experienced no foul air problems (although
> there was that bit about uncured concrete stealing the oxygen)
> although earlier biosphere closures had, because they pumped their
> air through a soil bed with a variety of carefully chosen bacterial
> cultures growing in it.
Uh-huh. Nuclear submarines have the same problem after a couple of months down. So what? Bad smells aren't lethal, and besides, the problem in conventional vehicles has as much to do with overcrowding and severe weight/volume/power constraints as anything else.
> As we extend human presence in space to larger populations and
> longer stays, more problems of this kind are going to come up.
> Your assertion about "mechanical systems and a decent energy source"
> has *never* been tested in a closed biosphere with a large human
> population over a long period of time, and I see no reason to accept
> it in advance of such testing. Don't confuse wishful thinking
> with practical optimism.
It seems to have escaped your attention that we are discussing a space program with access to nanotechnology, not one that is limited to 60s-era electromechanical contraptions. The processes needed to purify air and water are no more complex than those we would be using to produce fuel and chemical feedstocks from natural materials. That being the case, it seems perfectly reasonable to expect these problems to be quite easy to deal with.
Food production is more complex, as I said before, and we would be well advised to bring along lots of alternatives and allow ourselves a shakedown period in which to stabilize production. However, once again I can see no reason to expect agriculture in a space colony to be much more difficult than the ordinary kind.
Perhaps you could point out some specific problems that you think would be show-stoppers?
> The setup you propose with its "mechanical systems" *is* a biosphere
> which will have to be created, so of course moving self-sustaining
> food production into space will be exactly as difficult as creating
> an entire biosphere.
There is a vast difference between building farms and creating a rain forest.
Agricultural production requires only that we successfully grow a few dozen plant species in an environment where temperature, light levels and atmosphere composition are all subject to direct external control. This will, of course, require that we support a small variety of insects and microorganisms that are essential to the survival of said plants, but you don't need a complete ecosystem. As long as you can maintain the system in a stable state with a reasonable amount of human intervention you're in good shape.
The "Biosphere" approach, in contrast, requires that you create a completely self-sustaining ecology. You end up with at least an order of magnitude increase in the number of species involved, lots of extra biomass, and an unmanageable mess of interlocking feedback loops that are almost impossible to manage. Making it work at all will be far more difficult than in the agriculture approach, and making it produce food with any reasonable efficiency will be nearly impossible.
Billy Brown, MCSE+I