From: Robert Bradbury (bradbury@genebee.msu.su)
Date: Sat Apr 15 2000 - 08:14:33 MDT
On Fri, 14 Apr 2000, Technotranscendence wrote:
> On Sunday, April 02, 2000 5:53 PM Greg Burch GBurch1@aol.com wrote:
> > But I've come to a different conclusion now. The truth is that space
> > didn't pay and with 20th century technology it never could. I've yet
> > to see a good economic justification for the kind of truly massive
> > public spending required to do anything outside of LEO with that
> > kind of technology and, believe me, I WANT to see such a thing.
Greg, it has "relatively" little to do with the technology and a lot
to do with the volumes. I think there is a chapter in the Starflight
Handbook that deals with the fact that you have to have a *lot* of
people who want to go into space to make it work. The legacy that
Iridium may leave behind is the fact that is created a volume launch
requirement that may have permanently lowered the cost of getting
things into space. Rockets don't have to be terribly more expensive
than airplanes, they have to fly with airplane frequency however to
distribute the development and infrastructure costs over enough
seat miles to make such trips affordable.
>
> LEO is a start. (Actually GEO appears to be where a lot of money is for
> commercial satelites.) I think if the government space programs were shut
> down and private launch companies used exclusively, we'd see a lot of action
> in LEO leading to action higher up. My guess would also be that this would
> build a true infrastructure for space colonization, rather than the rickety
> one NASA has built, abandoned, and rebuilt.
I have my doubts. Tourism is the only application I could see that
would demand volumes that would bring ticket prices down $100K-1K range.
After you have your weather satellites, your multi-spectral imaging
satellites, your TV satellites and some comm satellites (rapidly being
displaced by fiber), *what* good is space? It doesn't have any resources
that humans, as currently engineered, really need that can not be obtained
for much less on the ground.
Now if you want to get creative, go for tele-operated no-holds barred
robo-wars on the moon. Get Sony to adapt that little doggie into a
robo-space-pit-bull and you would have dozens of teenagers saving
their pennies just to buy one and enter the games.
>
> > > Though I agree GNR will help make CAtS better, if we just took that old
> > > Saturn V design, which, if I'm right, is now unpatented, we could be
> > > making disposable launch vehicles that could put huge cargoes in orbit
> > > NOW!
There are plenty of other boosters that are reliable and have more efficient
designs that exist now if all you want is to put "cargo" into orbit. What
I think you mean is that you want to put large systems in space for efforts
oriented towards colonization and that fails the "humans are not designed
for space" test. If you want a rationale for going into space, you
need creatures that have an ecology *adapted* for space and use the
resources, esp. energy and minerals it provides. GNR doesn't immediately
result in CAtS. You still have to design the machines to do it. If
you get to the point where AI can do MNT design, then it will be AI
combined with MNT that will allow CAtS. What MNT does allow is the
eventual construction of an entirely space based ecology. That will
not make it an environment for us however. Sure, we can adapt it
to our needs, but conversely with that technology we can adapt
ourselves to that environment.
>
> I DISAGREE! The problem is not reusable vs. non-reusable. The fact that
> people think in those terms only shows how much this locks up the space
> mindset. Reusable rockets, like the Shuttle, have actually increased launch
> costs, according to David P. Gump in his _Space Enterprise: Beyond NASA_.
It depends how you do the accounting. Reusable only decreases costs
if the machines are reused as airplanes are, i.e. at high frequency.
If the complexity or safety requirements prevent rapid turnaround
times, then reusable is more expensive.
If you take the 1975 quoted cost of Apollo ($39 billion) and divide
it by some ~18(?) launches, that works out to something like $2 billion
per launch. That is still a lot more than $400 million (in Y2K $)
that a shuttle launch costs where you are putting up ~2x as many people.
(Of course the shuttle can't get you to the moon, so there is some
balancing that needs to be done.)
> > Daniel, if you're going to ask Earth to support an extraterrestrial
> > economy, I think you have to come up with an economic rationale.
> > I'm waiting . . .
>
> I'm not thinking that way, but I thought I answered this elsewhere.
As I recall, Daniel, those arguments seemed *thin* to me. For example,
you argue for space power with no comparative analysis of what a similar
investment in agricultural and/or electrical or transporation industries
would produce in terms of greater efficiencies that would eliminate
the need for greater power resources. As I've argued in other letters,
we are a *very* long way from the theoretical efficiency limits of
our current ecology. [For example, even a few $10's of millions put
into reversible logic designs would result in PC's in 10 years that
consumed much less power than those currently becoming ubiquitous
and consuming an ever increasing percentage of electricity produced.]
Robert
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