maddoxt@novavax.UUCP (Thomas Maddox) (06/27/88)
A short while ago, I posted a list of queries about the
design and functioning of space cities. As I explained in that
posting, I am currently working on a novel in which a
space city figures prominently.
So, as promised, here are excerpts from the replies I got.
J. Storrs Hall ("JoSH," moderator of the sci.nanotech newsgroup)
says, with regard to the overall design:
I would expect as much variation in space cities as ground
cities--lots of room for style, random variation,
"historical reasons", etc. Not to mention differences in
overall functionality.
Concerning the ecology of the city:
Genetic engineering will almost certainly be able to create
systems of artificial life that are specifically designed to
be the "opposite half" of a human-bearing ecology.
[A]ll the plants are designed for the job. I would expect
the plants to be the bio-engineered terminal nodes of the
climate control system. All wired into the "nerve net" of
the city. They act as sensors and controllers for humidity
and gas content of the air. They, and the lights and the
doors and a zillion other things are the "fingers" of an
intelligent environment. I suspect the intelligent
environment is not only a fancy extra, but will be
considered a necessity for safety reasons.
And the economic infrastructure:
An early occupation of the space city will probably be the
manufacture of antimatter, and genetic engineering, and
other pursuits that involve tiny, dangerous things,
presumably carried out in nearby, detached, facilities.
And the politics:
Take a population of smart, intellectually aggressive people
in close (confined) social contact, all dependent on the
same integrated system for their lives, and you have a sure
recipe for the hairiest, fieriest, politics in human
history.
One of my central questions concerned an asteroid that my
city dwellers would discover, snag, and transport to the space
city. JoSH says,
To my surprise, when I worked out the math, this will
actually work. Solar orbital velocities in this area are
about 30 km/sec, and for a 100-meter asteroid massing 1e11
kg, that represents 3e14 watts of kinetic energy. Assume we
can build a 10 gigawatt fusion plant (modern fission plants
are 1 gigawatt) it can supply that amount of energy in a
year. Build more plants (or assume more powerful ones) and
time shrinks. You still need transit time after the thrust,
of course.
The thing could be up to a mile (multiply above numbers by
200). They could find it anywhere inside Jupiter's orbit,
depending on the time constraints of the plot. There are
occasional asteroids that cross Earth's orbit, though most
are found between Mars and Jupiter. You would not be too
far off base to assume the composition was any fairly small
distortion of earth's. Silicates, boron, nickel, iron.
Spice it with rare earths to fit the plot.
Marc Ringuette says,
The spokes are very useful things - probably exercise gyms
and recreational facilities at anywhere from null to full
gravity, as well as science research, hospital recovery
facilities . . .
I presume there'd be a fair bunch of non-rotating zero-g
docking, communications, maintenance, and research modules.
So what are some idea-generating features of the
environment?
- variable gravity available
- vacuum available
- linear organization of the city (a skinny loop)
- closed society. towns of 10,000 barely have a swimming
pool!
- high tech population - jobs are space, mining, science,
astronomy
John Turner, from L5 Computing, Edmonds, Washington, writes:
1) Be sure to portray the window shielding right. I don't
remember whether Heppenheimer's book mentioned the chevron
shields. They are cribs of some dense material faced with
mirrors, supported on metal legs above the torus windows.
Sunlight follows a crooked path through the mirror maze this
creates, with the hard radiation absorbing harmlessly into
the rock, metal, etc. that fills the cribs. Try to find a
diagram if you don't have one already; without the chevron
shields a Stanford torus is a joke.
2) Don't make your metal asteroid much larger than five
hundred meters across, about one-half billion tonnes mass.
The motors for moving such a beast would rate around 100,000
tonnes thrust for a fairly speedy trip, less if a few
microgravities is all you'll need. Many plans for mining
such small objects include a sort of bag surrounding the
body, to catch flying shards during blasting or excavation.
[. . .]
5) Spin gravity isn't the same as the real thing. The
coriolis effect in even a large structure like a Stanford
torus could be *felt* as a weak vertigo if you rocked your
head, twisted it side to side. Gossip has it that you could
find the spinward direction from anywhere in a Stanford
torus by nodding your head a few times.
6) Space eats your brains out. Even inside the stationary
"bicycle tire" shield and window shielding of a Stanford
torus, enough radiation gets through to make personal
dosimeters a good idea. Traveling through the unshielded
spokes would cause blue splotches to dance before your eyes;
they are called phosgenes and are a visible (to you)
manifestation of dying brain cells. Too many dead brain
cells and you'll be a vegetable, fed blue liquid down a
tube.
Space settlers would be almost obsessive about tracking
their radiation histories, and would forbid their children
access to poorly shielded areas.
Douglas F. DeJulio, from Carnegie-Mellon, suggests,
How 'bout several concentric toruses (torusi?) of different
sizes, with different rotational speeds? The closer to the
center, the faster the spin.
That way it covers more area (because you have people live
at more than one radius) and you have similar gravity in
each ring. Travel from ring to ring would be interesting.
Travel *within* a ring could be done by hopping to another
ring, waiting, and hopping back in a new place.
And Jack Campin, from Glasgow University, asks:
OK, what about radiation shielding? I don't recall any of
the advocates of space colonies having an answer to the
infrequent (every few decades) but REALLY lethal blasts of
solar wind that are detectable in the tree-ring record by
the C14 they generate (see last week's New Scientist). You
could maybe have enough lead boxes for the humans, but for
the whole ecosystem?
(The answer I have: the rotating ring of the torus [and the
central hub] would be protected by a shield of crushed lunar
rock; light would be reflected into the ring through a system of
mirrors and shields, the chevron shields alluded to by John Turner
above. Travel through the spokes would simply be prohibited
during radiation storms. Anyone got a comment or refutation on
this topic? It's obviously of overwhelming practical
importance.)
Dani Eder, who works for Boeing on the Space Station program,
writes:
You are trying to retrieve a stony-iron type [of asteroid]
(because of the variety of materials found within). You
start with a solar concentrator and heat up some metal found
in the asteroid then roll it out in thin sheets. Us this as a
bigger solar concentrator to melt more metal, etc. bootstrapping.
The sheets are attached to 'masts' made of extruded bar
stock of the same metal. Use refractory oxides from the
'stony' part to make the dies through which the bars are
extruded.
This assemblage becomes a solar sail , so that the asteroid
sails ITSELF to earth orbit.
Rick Crownover, from Duke University, promises more and writes
concerning the city's orbit:
A quick note on the design: oblate and prolate ellipses are
ok also, and if you look in the letters section of IASFM's
June issue, there is discussion of a counterbalanced
"pendulum" which might suit your needs quite well -- even
has a useful place to park the asteroid.
J. Eric Thompson writes from "Flatline" (I'll tell Gibson about
it, if J. Eric will tell me what it is) in Houston, concerning the
city's biological functioning:
Soybeans. Lots and lots of soybeans. You can make lots of
stuff from soybeans. :-). Seriously, though, everything
from food to clothes, and that's just from non-genetically
engineered plants. No telling what you could do with a
mutant strain or three...
And concerning social life:
A closed environment of 10,000 people can be really nasty.
(Says he who lived in a small town of 10,000 people for a
few years).
Without a changing population (immigrants and uh . . .
outer-grants?) stable family lines may develop. Also, the
"everybody knows everybody else" starts to develop.
Minorities. Especially blacks, hispanics and homosexuals.
They seem to get left out of most future-novels . . .
Especially blacks and homosexuals. There're a thousand
orientals it seems, and a hispanic every now and then, but
they're mostly minor characters. There seem to be no blacks
in science fiction. Well, in Gor... :-)
I take that back. My SO just read a book where the central
character was a black female. I can't remember the author's
name, though . . .
(Wouldn't be Octavia Butler, would it?)
Homosexuals. Mistreated more than females.... Oh well.
It'd be nice to see a future community where a wide spread
of people are represented. . . .
Beverly Erlebacher writes from Toronto:
the most land-efficient agriculture is found in southern
china and other parts of southeast asia. under very good
climatic conditions and meticulous hand cultivation, an acre
can support about 5 people with enough calories for
reasonable health. . . . a closed ecology with cheap power
and labour might optimise for maximal nutritional value
produced per square or cubic footage per unit time.
under such a system, green vegetables would be cheap and
plentiful, most carbohydrates would come from root crops
like potatoes and tropical yams rather than from grains, and
tree fruits would be incredible luxuries. small amounts of
meat, eggs and milk could be produced by rabbits, chickens
and goats or cattle consuming garbage and agriculture waste.
on the other hand, fish would be much more available. as
part of the water recycling system, there are large tanks of
algae cultures feeding fish such as tilapia and possibly
some invertebrates. nutrients for the hydroponics come from
the same system.
in your book, you might consider some of the lush tropical
vegetation being food plants like fruit trees and squash,
bean, melon and grape vines.
on another topic, that of air, you might want to read the
may issue of scientific american which had an article on
indoor air pollution. up here in the north, in order to
save heat, new buildings are often tightly sealed and air is
recirculated. these buildings are really awful to live and
work in. the air has a bad character to it, and people
often get headaches or a sort of general dopey feeling after
a few hours. colds are much more common. unions have been
trying to get things changed for their workers on these
issues.
i could do some hand waving about 'wild' animals and birds
in your space city, but for now, i think i would just
recommend you avoid importing rats, mice, pigeons, sparrows,
starlings, rabbits and red deer. on the other hand, these
critters are pretty well guaranteed to succeed. :-)
Finally, Graeme Williams writes from somewhere I won't mention:
I have one observation on what sort of society might develop
in a space city, assuming that it is driven by technology
and doesn't end up re-creating small-town Kansas.
Fashion is possible (only?) when trivial changes in form are
possible with negligible changes in function. Observing my
colleagues . . . we have that in spades.
This sort of change interacts with our organizational
culture, which seems basically tribal. We are of course
organized in a hierarchy, but as you might expect this has
the most impact at the level of sections (up to about 10
people) and departments (up to about 50, although above
about 35 it doesn't really seem stable).
This posting having grown quite large, I'll abandon it
(though I may return to the topic later with comments and further
queries) by saying thank you to all who took the considerable
trouble of thinking about and replying to my questions. All the
replies were intelligent and well-informed, many gave gratifying
detail. I have benefitted enormously from reading them, and you
may consider me in your debt.
If I have slighted anyone, or improperly identified anyone
or his or her affiliation, my apologies: I simply wanted to give
proper credit.
By the way, I'm still happy to receive responses.