Space Settlement FAQ's]

More from Dennis May, responding to Mike Combs.

Monart
~ * ~
Starship Aurora

Subject: [Starship_Forum] Re: SpaceSettlement FAQ's
Date: Thu, 15 Nov 2001 17:55:39 -0600
From: Dennis May
Reply-To: Starship_Forum@yahoogroups.com
To: Starship_Forum@yahoogroups.com

Mike Combs wrote (11/15):

> ...the recommendations of the
> NASA-Ames/Stanford Summer Study Group. They assumed the metal and glass
> structure of the habitat as well must come from space-derived resources
> to be economical. For myself, I'd have to say that building such a torus
> at even 1/2 or 1/3 of the scale but entirely from Earth-boosted components
> doesn't sound very likely to me, even if the shielding did come from space
> resources (but granted, that's the lion's share of the total mass).

I don't doubt that a dozen men could build
such a structure and I don't doubt that
a Study Group found it feasible to do so.
I do however doubt that it is economically
sound to wait the many years it will take
for such a small crew to pull off such a
task. I work with a group of fabricators
who are more qualified to do such work than
any existing astronauts. They could do it
but NASA has a history of underestimating
costs and time frames by hundreds if not
thousands of percent. They may envision
the project taking a few years, I would say
a few decades is more likely. Underfunding
and underestimates drive prices even higher,
cause inefficiencies, loss of moral, loss of
support, and worst of all huge unseen time
related losses.

The first habitat built will require
re-building or replacement before the puny
infrastructure could produce a second one.
The huge number of re-supply missions for
such a puny payback in infrastructure does
not adequately address long term needs.
Economies of scale apply to space as they
do anywhere.

I wrote:

> A circular track on the moon sheltered
> from radiation fixes both problems.

Mike Combs wrote:

> Again, you seem to proceed from the idea that this circular track and
> large, high-speed vehicle is going to be easier to construct than a small,
> rotating, shielded habitat in orbit. Both construction programs would take
> place in vacuum, and well away from the Earth. I don't see
> the lunar track being all that much cheaper. Once a small habitat is set
> rotating in orbit, it basically will rotate forever.

It comes back to a disagreement over the
critical mass of people required to create
an industrial infrastructure in space. I
see it taking 10-20 times more people than
the estimates of NASA think tanks. I would
have to see a prototype materials production
factory function for an entire production
run of creating such a habitat before I would
believe their estimates. Then after they
produce one run I would double the actual
required time to take into account problems
not encountered in the first run done under
ideal laboratory conditions.

I cannot emphasize enough that time is as
critical a component in economic calculations
as is upfront money. A well thought out
initial Moon infrastructure will make
everything done afterward function much
faster and much more efficiently.

Mike Combs wrote:

> And if there were no such thing as CC type NEOs, I'd agree that Mars would
> be next.

I'm sure they will be of great value but
the time issue involved in developing them
for mining should be a large consideration.
I would expect investors will see Mars
as further but having larger long term
promise. Until the first CC type NEO is
mined they will remain largely a question
mark regarding how efficiently and
economically it can be done.

B.T.W. I created a work of art in 1984
showing the mining of a CC type NEO.
It was part of a college class. I want
them mined but I am not convinced they
would be the most logical place to look
for resources at the beginning of
an expanding infrastructure.

Dennis May