At the risk of bursting the bubble, what's the purpose of a space elevator? There's zero point in putting people into space (no, we apes are never going to be a "star going species") because robotic missions can do much more, much faster, for much less. Sure, there will be some tourism, but that's hardly the basis for a $400 billion engineering endeavor (to estimate the cost look at current projections, then multiple by the average cost over-run for every other ambitious leading-edge engineering project over the last 50 years). Although rockets aren't a very elegant solution the per-kilogram launch cost continues to fall dramatically, thus invalidating the supposed financial benefit of the hypothetical elevator. All in all, given the huge challenges and the meager rewards, the space elevator will remain the stuff of cheap Sci-Fi - and probably just as well, as the hazards it would create would be horrific.