As I understand, part of what's changed is that materials for a space
elevator are now becoming available.  I don't think that the space
initiative has anything to do with it.  There are a few companies (such
as Liftport - http://www.liftport.com/) who have been talking seriously
about elevators for a while now - well before Bush's space initiative
was announced.

I thought Zubrin's  "Entering Space" an excellent book.

Barry

Helge Moulding wrote:

>Barry Haworth wrote,
>
>
>>The interesting thing is that, if these guys are right, we'll be
>>getting a space elevator *before* we have widespread space travel.
>>Both Clarke & Sheffield had their elevators built well after space
>>flight using more conventional means had become widespread.
>>
>>
>
>I wonder if the economics of conventional means were ever as clear as
>they are now. Zubrin talks about the economics in _Entering Space_. The
>current cost is in the thousands of dollars per pound of payload, partly
>due to the technological choices we're making. Zubrin seems to think
>that we could reduce the cost by a couple of orders of magnitude, even
>with conventional rockets. Back in 2000 David Smitherman (Space
>Elevators: An Advanced Earth-Space Infrastructure for the New
>Millennium) suggested the cost by elevator might be a couple bucks per
>pound. Smitherman also figured that it'd take maybe 50 years to build
>it. I gather some people are now, just 4 years later, saying we could do
>it in less than 20 years. What changed, besides Bush's proposed space
>initiative?
>--
>Helge Moulding
>mailto:[log in to unmask]                Just another guy
>http://hmoulding.cjb.net/                  with a weird name
>
>.
>
>
>