very interesting NASA space elevator study

Thanks for the schooling on intermediate solutions. You wrote,

"then you should take it seriously, because it's not
necessarily more than about 10 years away"

You've got that right: anything that smells of being more than 10 years
away, even with significant investment, makes my eyes glaze over and I
loose interest.

Yes, I've seen http://www.tethers.com/ before. I'm particularly excited
by their near-term ideas such as electrodynamic reboost of ISS Alpha.

Ron
******

"johnf4303"
12/14/01 10:35 PM
Please respond to spacesettlers

To: spacesettlers@yahoogroups.com
cc:
Subject: [spacesettlers] Re: very interesting NASA space elevator study

Al Globus wrote:
> See http://www.niac.usra.edu/studies/ and find the space elevator
studies by Bradly Carl Edwards. There are two.

His 'Phase 1" is the hypersonic skyhook. It doesn't require
unobtanium materials, just presently used things used in different
ways (Spectra 2000 polyethylene in presently unheard-of lengths, and
any of a number of approaches to protecting it from atomic oxygen &
such).
The link from that NIAC site goes to an article that has been around
for a while. To see it without the NIAC frames, go directly to
http://members.aol.com/Nathan2go/SPELEV.HTM
Edwards also referenced the "affordable spaceflight" site. It's
worth a look. (again, without the NIAC frames)
http://affordablespaceflight.com
See their "step 3" for the hypersonic skyhook

His 'Phase 2' is the geosynchronous skyhook or the Beanstalk. Before
carbon nanotubes became lab curiosities, it was mainly used as a
numbers exercise, and ridiculed for its' impossibility.
That same NIAC site also has another article on the HASTOL (or
Hypersonic Skyhook)

> His approach is very clever and is significantly less impossible
than any other space elevator concept I've seen. It actually looks
almost as possible as landing a man on the moon must have looked in
1961.

There are "Space Elevators", there are "skyhooks" and there are
"tethers" (presented in reducing level of "impossibility", as
displayed by the nametag you label them with. If I talk of a tower
built up to GEO, you laugh. If I talk of a GEO beanstalk, you point
at the difficulty of using giga-tonnes of Buckytubes. If I talk of a
50km, 500kg multi-stranded, ballasted tether momentum-exchange
facility, then you should take it seriously, because it's not
necessarily more than about 10 years away, possibly made of
fiberglass!).
It's important to differentiate them. (Relatively) simple, small,
rotating, momentum-exchange tethers are as "less impossible" as the
first manned Apollo flight was in '61.

Have you seen Tethers Unlimited?
http://tethers.com/
They've been at it for a while, with several innovations to their
credit. They're presently working with NASA & Boeing, developing a
few very near-term approaches.
See especially (articles under the "TU Products" sidebar, provided
here without frames)
Tethers for Earth-To-Orbit Launch
http://tethers.com/HASTOL.html
Tether Boost Facilities for In-Space Propulsion (and the NIAC
sponsored article they've got in the "Tether Boost Facilities"
article under the "TU Products" sidebar)
http://tethers.com/LEO-Lunar.html
MarsEarth Rapid Interplanetary Tether Transport
http://tethers.com/MERITT.html

Note that the Cis-Lunar system is basically a scaled-up version of
what Bruce Mackenzie talks about in the "Bootstrapping" article I put
in this group's links.
http://www.ari.net/moon/forum/mp/mp-4/bootstrap.html
Don't let the cartoons fool you. There are some good points in there.
Note that he deliberately uses small near-term systems, and part of
the bootstrapping is to prove it out gradually, and build it up while
eking out whatever profit you can.