Obtainable Ringworld around the Earth?

Greetings,

I don't think you need that strong a material, a
tapered Kevlar ribbon would do. If any of those
reading about these "Orbital Ring Systems" as Paul
Birch described them in his (JBIS, 1983) article, are
in the Space Elevator Group, they might want to pass
this info to there group.

This system is about 100 time more useful that the
space elevator to GEO, and would cost about
1/1,000,000th the amount a space elevator to GEO would
cost, assuming it were possible to obtain the Carbon
Nanotube fiber material for the ribbon. Furthermore
this ring system could be built now with existing
materials. More useful in that it could take more
material to orbit faster and cheaper.

The amount of mass that must be launched for this is
still pretty sizable, even for the start up ring from
which the full-scale ring could be eventually lifted.
Sizable means 1,000s or 10,000s of tons, so it's cost
(just for launch) would be in the $100B range.

Clearly massive space projects like this require a new
Very Low cost launch system. The best one that may
fit the bill is called "the Telephone Pole Launcher"
invented by By Henry Kolm (L5 News, September 1980),
see
http://www.nss.org/settlement/L5news/1980-massdriver.htm
But even this launcher would cost $3B-$5B today.
Maybe a scaled down version of the TPL could be built
for $2B to $3B, but who has that kind of money? Even
if it came from our taxes, that amounts to $10.00 to
$15.00 from every man, woman and child in the U.S.!

Regards,

Dave Handwerk

--- Xenophile wrote:

> --- In spacesettlers, "Lucio de Souza Coelho" wrote:
>
> > Another Ringworld-related problem that I forgot is
> dynamic
> > stabilization. Since this structure would not be
> in orbit, behaving
> > instead like a "solid" ring around Earth with the
> center of mass
> > matching that of Earth, some portions of it could
> be slightly closer
> > to Earth than the others; and as a result the ring
> would be
> > irrevocably pushed toward Earth from some side and
> be destroyed.
>
> Well, I've got a simple solution to that, but it
> strays into
> unobtainium territory. Not by much, though.
>
> Since the ring is geostationary (despite being at
> Shuttle height), you
> could have a bunch of space elevators connecting it
> to the ground.
> Then, if one side drifts closer to Earth, the other
> side has to drift
> farther away, and the elevator ribbons won't allow
> that. You could
> position one, say, every thousand Km around the
> equator, giving you
> forty of them.
>
> And a tether that can support itself for 200 Km is
> probably more
> "obtainium" than one which can support itself for
> 35,792 Km.
>

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