(above from Get Your War On).

Historically, crossing oceans and setting up farmsteads on new lands conveniently stripped of indigenous inhabitants by disease has been a cost-effective proposition. But the scale factor involved in space travel is strongly counter-intuitive.

[…]

We’ve sent space probes to Jupiter; they take two and a half years to get there if we send them on a straight Hohmann transfer orbit, but we can get there a bit faster using some fancy orbital mechanics. Neptune is still a stretch – only one spacecraft, Voyager 2, has made it out there so far. Its journey time was 12 years, and it wasn’t stopping. (It’s now on its way out into interstellar space, having passed the heliopause some years ago.)

[…]

Space elevators, if we build them, will invalidate a lot of what I just said. Some analyses of the energy costs of space elevators suggest that a marginal cost of $350/kilogram to geosynchronous orbit should be achievable without waving any magic wands (other than the enormous practical materials and structural engineering problems of building the thing in the first place). So we probably can look forward to zero-gee vacations in orbit, at a price. And space elevators are attractive because they’re a scalable technology; you can use one to haul into space the material to build more. So, long term, space elevators may give us not-unreasonably priced access to space, including jaunts to the lunar surface for a price equivalent to less than $100,000 in today’s money. At which point, settlement would begin to look economically feasible, except …

We’re human beings.

[…]

Colonize the Gobi desert, colonise the North Atlantic in winter – then get back to me about the rest of the solar system!

Very good article, lots more detail besides what I’ve excerpted here.

Full Story: Charlie’s Diary.