Starting out small

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Dan Wylie-Sears

> How important is it to have the option of expanding the same
> colony, over a large size range, rather than building
> separate new colonies?

That seems to be a recurring point of contention between the original,
1970's concepts of space habitats, and more recent attempts by some to
update the concept. In the original designs, it was considered no big
deal that you had to build the entire habitat before you could move in,
and that when expansion was desired it would be accomplished by building
another habitat, rather than by attempting to somehow enlarge the
original structure.

I still don't have a problem with it. It's important to remember that
even Earth-like habitats would start out at the Bernal Sphere or
Stanford Torus level, so expansion would occur in discrete units with
10,000 population capacity. Even by the time we've moved up to the
Island 3 stage, it's occurred to me that one needn't necessarily develop
the entire interior of a cylinder at once. One might initially only
develop one end of each of the three valleys, leaving the biggest length
of each unfinished (perhaps provided with soil but left without
landscaping or other furnishing), and then only grow down the length of
each valley as population increases.

For some reason, some more recent thinkers seem to feel that it's
vitally important for the habitat to be able to grow in size but remain
a single unit. And (as Ralph touched on) I've even had it argued to me
that we must settle Mars rather than orbital space because on Mars we
can expand incrementally, whereas in orbit we must always build a
completely new habitat to grow. (I'm unconvinced that this outweighs
the many good points O'Neill made about orbital locations.) Other than
its discrete vs. incremental nature, I'm not sure what the objection is
to a new habitat vs. enlargement of an existing one. Maybe people are
thinking about the fact that going from one habitat to another will
always involve "space travel". But I've often visualized a string of
co-orbiting habitats interconnected by a maglev system. In that case, I
don't see a big advantage to enlargement of an existing structure vs.
replication of the small structure you're living in. In fact, I can see
the many small structures as being safer in the sense of being more
segmented and isolated.

Coming back to my "baton" suggestion before, I suppose one might start
out with a two-armed baton, and then later expand it to four arms. One
might even do it without halting the rotation, if one was cautious about
keeping construction workers and equipment from "falling off" (being
flung off, actually). Then four arms might later get extended to six
and then to eight. Somewhere along this process it would be
advantageous to install curving tunnels that connected each sphere to
its neighbor, so that one needn't go all the way up to the spin axis
just to get from one sphere to the other (and can remain under normal
gravity for the entire trip). So one might start out with a baton, and
in the long run wind up with a torus-shaped bead necklace.

Regards,

Mike Combs