I am not sure about the concepts of 'impossible technology' mentioned here. There has actually been a lot of serious thought by real scientists into some of the technology discussed in this article and the concensus is that some of it is plausible theoretically if not practically possible now...
Replicators (one thing I have not read anything on yet) are surely along from the tech tree from current recycling technologies. You put in stuff you don't want (torn clothing, old newspapers, tin cans, faeces, urine etc) and these things are broken down to make an atom soup which can then be used to make other stuff - food, water, clean clothing etc. Ok, the breaking down and reforming bit is hard but I can see us getting there eventually.
FTL travel has been extensively discussed and I have seen a number of serious science tomes takng the concept seriously. Two main methods - wormholes and warp drive - have been considered possible by physicists (I would quote which ones but my book collection is somewhat out of the way at present... moving...). Wormholes avoid Einstein's theory by shortcutting through the universe but require technology we don't currently have (including something called exotic matter, ask a phycisist if you want to know what that means, I'm too scared in case they answer
) to make the wormhole stable. Once that is achieved, however, phycisists predict that FTL is possible using one of these.
warp drive (according to one book I read) requires creating a field of warped space around your vessel which you can (apparently, my understanding of this is not good, there were equations...) move through space in a way that means you can avoid the issues of relativity. Again, it is possible if advanced tech were available. Though one issue that was mentioned was that, due to relativity, people in the front of the ship would be in a different rate of time than those in the back of the ship... they may also be moving at different speeds which means the ship may fall apart...
As i say, all of these are well into the 'if we had some as yet undiscovered scientific concept' area of physics speculation but it does show that Sci fi quite often gets it right and also science and science fiction do feed off one another...
I was surprised they did not mention Space elevators, though... from what I have read we are close (with current nanofibre technology) to making Arthur C Clarke's idea of energy neutral space travel a reality. For those who don't know what it is, its a giant elevator hitched to a geosynch satellite which can be used to transport men, equipment and supplies into orbit without needing to use loads of expensive rocket fuel. It is energy neutral because you lift an equal weight to what you are lowering so the carriages counterbalance.
The only reason no one has yet considered building them, I think, is because of the massive initial cost. Governments in general are interested in short term results so they can win elections and so are quite happy to spend, say, 6 billion to put a man on the moon or mars for the publicity but less willing to spend 20 billion or more on an ongoing project which may not even be complete by the time their term ends and so someone else takes the credit for
A lot of interesting thoughts in the article, though, and well worth a read for anyone wanting to consider realistic space travel. Much of this I already knew from my 'Physiology of unusual environments' module at uni...
