At this point in history, tremendous human progress becomes possible through converging technologies stimulated by advances in four core fields: Nanotechnology, Biotechnology Information technology, and new technologies based in Cognitive science (NBIC).The preceding was written in 2005. Do we even hear about NBIC any more? Here's a current summary. But it's certainly not from a mainstream source. Yet work proceed in all four areas. There's just less over-excited talk of convergence these days.
But what's my point? My point is that all four of the NBIC areas share one thing that distinguishes them from Space. (This blog post was inspired by Obama's speech on space and the future of NASA tody.) The four areas focus on information manipulation—the moving about of physical objects that represent other things, and doing it with relatively small amounts of energy. In contrast, space requires lots and lots of energy to move things about. Obama talked about developing a new "heavy lift" rocket. That's big energy technology.
Humans have succeeded in the past by developing big-energy technologies: factories, transpiration, etc. But we are succeeding in the present—and most likely in the future—by focusing on small-energy technologies, namely NBIC.
I guess it's still true that we need big-energy technologies. We still fly; we still manufacture machinery, etc. But all those big-energy technologies seem somehow 19th and 20th century. The late 20th and the 21st century seem destined to focus on small-energy technologies, where a little bit of energy provides a lot of leverage.