Re: [unrev-II] It could have happened...

From: Paul Fernhout (
Date: Fri Nov 10 2000 - 17:32:52 PST

  • Next message: Eric Armstrong: "[unrev-II] Stardates"

    Eric Armstrong wrote:
    > Fascinating stuff. Thanks for those links.

    You're welcome.

    > Never knew such designs existed.

    Shows a failure of NASA and sci-fi authors to educate us all about the
    real future in space... Even the sci-fi show Babylon 5 mangaged to make
    the interior of space habitat look like a badly lit submarine
    (supposedly the center was devoted to agriculture and so was rarely
    shown and no one could go there -- all because they couldn't think of a
    cheap way to show it).

    > Distant cataclysms and remote-probability
    > events don't concern me so much. But I suspect
    > that we are looking at more than one highly
    > probably cataclysm in our lifetimes, due to
    > the combined effects of overpopulation and
    > environmental damage, if nothing else.

    When you through in the possibility of runaway technology with
    unexpected effects, I would tend to agree.

    > The "habitat" idea is tres interesting.


    > But while the FAQ dismissed the idea of a
    > meteor as the low-probablity event it is,
    > a saw no discussion at all of the effects of
    > *very* common meteorites.
    > When your atmosphere is held within a shell,
    > as it were, rather than held within a
    > gravitational shield, what happens when a
    > meteorite punctures that shell? In the current
    > arrangement, they burn up in the atmosphere.
    > But we have a few miles of atmosphere, and
    > an "inverse" shell to hold it here. How do
    > the space habitats deal with that?

    The ratio of volume to surface area in a large (10KM wide) space habitat
    is fairly high. That is, there is a lot of air in them relative to the
    shell. Think of how long it takes to inflate or deflate a hot air
    balloon with a fan (tens of minutes). Studies show that even with a
    major hole (I think a meter in diameter?) in the space habitat shell, it
    would take 24 hours for all the air to escape. (Don't have the exact
    reference). That is plenty of time to apply a patch. You can have
    balloon patches that float around neutrally boyant and would be sucked
    into a small hole and plug it. In the case of the Savage/LUF bubble
    model, you have a six foot water shield at no or little pressure which
    would show any punctures by a stream of water.

    I'd be more worried about terrorism or ineptitude as far as disaster in
    a space habitat. But these are to some extent the same risks to life
    present when living in any technological artifact like a major city, an
    airplane, or a cruise ship.

    The good point about space habitats is the modularity. Since they are
    self-contained, disasters are localized. The problem with our current
    economy (and society) is it is not fairly modular -- so it is
    unpredictable and prone to widespread chaos.

    My interest in space habitats grew stronger initially in the 1980s as a
    response to the threat of nuclear war (think "The Day After" movie).
    Rather than expect arms control to succeed (not that we shouldn't try)
    or build even more terrible weapons as deterrants, I thought one could
    respond to the threat of destruction by growing faster than nuclear
    weapons can destroy -- the same way self-replicating duck weed survives
    on a pond despite rampaging flocks of ducks that find it tasty. Even
    though every duck weed plant is fragile and relatively defenseless
    (barring plant poisons), a duck weed population on a large pond is
    almost impossible to remove entirely.

    -Paul Fernhout
    Kurtz-Fernhout Software
    Developers of custom software and educational simulations
    Creators of the Garden with Insight(TM) garden simulator

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