Space Elevators, was Re: [extropy-chat] good space shuttle article

[Jay Dugger]

Probably time to change the subject line...

On 8/3/05, Mike Lorrey <mlorrey at yahoo.com> wrote:
> Actually, I wouldn't mind riding a real bomb propulsion system. Orion
> needs doing. Five moderate sized nukes could put an aircraft carrier
> worth of cargo and spaceship into orbit. I think the trade off is worth
> it.
> 

The statistic I remember from "Project Orion" is something like more
mass to orbit in the first flight than in every shuttle flight
combined.

> Space elevators are a penultimate system to develop, but we've got to

Next to last? What trumps an elevator?

> build lots of rockets between now and then to get the mass into orbit

Yes, one or two presentations at the 2nd conference (available
on-line, check del.icio.us or Google) talked about what sort of
heavy-lift we need for it. Edwards and Westling's book, "The Space
Elevator"  discusses this on pages 73-86. They assume exotic
spaceships such as the Shuttle, the Delta IV Heavy, the Atlas V, and
one paper spaceship--a Shuttle C.


> we need to build the tools to build the tools to build the space

Edwards and Westling propose doing as much possible on Earth--that's
where the industrial base lies. The basic model is to lower a small
cable from GEO, use that to raise a slightly larger cable, use that to
raise a slightly larger cable, repeat. Once done, quickly build
another elevator to provide dedicated elevators for up and for down.

> elevator. Besides that, we don't even have buckycable yet. Baby steps.

Baby steps indeed. Again, Edwards and Westling suggest not the
six-meter thick diamondoid monster from Robinson's "Red Mars," but
something more like a ribbon of scotch tape reinforced by
aligned-through-extrusion nanotube fibers. Weird that you get
something that looks like strapping tape from the corner store, but
they develop the argument in very good detail on pages 19-37.

As I remember, the latest problem with a SE was vibration, harmonics,
and damping. Damien Broderick gave some attention to this during the
conferences. Any comments, D.B.?


Now for some more fun speculation. In some computer war-games I
played, building a space elevator was an offense punishable by
surprise cybernetic or nuclear attack. In game (and real-world) you
could do things such as fractional orbital bombardment at low cost.
Run your troop drop-ship up the elevator just high enough, release,
brake, and steer. While this would have been great for package
delivery and high-speed passenger traffic, in game you could only move
military units.

Just how destabilizing would an SE prove? The first group to do it
gets a big advantage. See Edwards and Westling [152-155]. This seems
to depend on surprise applications. Deployment of a ribbon to Mars,
while long-term, (first SE + ~8 years), gets predicted. What
inevitable surprises do you all think might happen?

-- 
Jay Dugger
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Sometimes the delete key serves best.