Yahoo group Return to the moon
From:  "vincecate" <vince@o...>
Date:  Fri Jan 16, 2004  7:05 pm
Subject:  [Return To The Moon] Re: Rotating Space Tethers

"tater schuld" <taters1@c...> wrote:
> but is it cost effective? usualy when you have to rely on
> exotics all chances of it being feasible for use go out
> the window.

Designing for not yet existing materials or engines is what
gets you in trouble. The cable is the same Spectra-2000 that
is used in fishing line. This is not like a "space elevator"
that needs carbon nanotubes joined together in a yet to be
determined method. Nanotubes are so short and so slippery
that it is very hard to join them together to make a cable.

Space tethers are reusable infrastructure that let you use a
much smaller suborbital rocket. Because the rocket does not
have to do so much it is much easier to make a reusable rocket.
Also, it does not have to do an orbital speed reentry,
so again it is easier to make it reusable.

For two way traffic you get to recycle your energy from the
mass going down. For one way traffic you can use a high ISP
thruster to replace momentum (or an EDT, or a solar sail).

I seems to be amazingly cost effective. I can not understand
why it is not more popular.

-- Vince