Actually, we will _never_ build large space or Mars colonies, because we have Venus for second home. Venus is after initial costs cheaper place to live than Earth, because solar energy at Venus is free (far cheaper than e.g. thermal cold fusion electricity could be), because outside temperatures are optimal for solar cells and solar flux is very high.
The pressure problem however is really difficult and it helps greatly if orbital habitats are kept at low pressure. I could not even imagine comfortable living in vacuum. Imagine landing with airplane at worst and multiply that with figure 100. Then you should get a feeling how radically uncomfortable pressure changes are at high vacuum habitats such as in Mars, Mercury and L1 points. There is no such thing as routine when we are dealing with high vacuum. There is also radiation hazard in orbital habitats. Of course ISS will get company and I would predict that in 2020's we are starting to build second generation space station with artificial gravity enabled into high lunar orbit. Perhaps into L1 point, what would be suitable anchor for lunar space elevator. Near Earth Asteroid material is relatively cheap to collect into high lunar orbit and it should compensate higher launch costs. In that Popular Mechanics article there was one very good and urgent prediction, that Connecticut could alone feed the world if advanced vertical farming projects are utilized. Vertical farming is the key idea why it is so cheap to live in Venus. For Earth as a living planet, vertical farming is essential, because we have already solved all environmental problems expect those that are related to horizontal agriculture. With advanced vertical farming there is no more such thing as environmental problem that is uncontrollable. —Jouni On Dec 16, 2012, at 10:29 PM, Jed Rothwell <[email protected]> wrote: > This kind of thing is such fun! See: > > http://www.popularmechanics.com/technology/engineering/news/110-predictions-for-the-next-110-years > > I have a book from 1890 with predictions by people such as Westinghouse for > the year 1990. A lot of them were smack on target. In some ways it is not so > difficult to predict the future. > > The latest issue of Sci. Am. is devoted to future predictions. Most of the > authors wimped out. They did not even take a stab at future computers. One of > them said that space-based cities would have to have low pressure, which > might affect the health of children. What a nitwit! Does he really think we > can build cities in space but we can't develop materials strong enough to > hold 1 atm of air pressure? > > - Jed >
