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- Path: sparky!uunet!paladin.american.edu!darwin.sura.net!mips!sdd.hp.com!ux1.cso.uiuc.edu!news.cso.uiuc.edu!uxa.cso.uiuc.edu!tjn32113
- From: tjn32113@uxa.cso.uiuc.edu (Thomas J. Nugent)
- Subject: Re: Beanstalks in Nevada Sky (was Re: Tethers)
- References: <63811@cup.portal.com> <1992Aug11.124107.1@fnalb.fnal.gov>
- Message-ID: <Bsw5rI.6C2@news.cso.uiuc.edu>
- Sender: usenet@news.cso.uiuc.edu (Net Noise owner)
- Organization: University of Illinois at Urbana
- Date: Wed, 12 Aug 1992 22:14:02 GMT
- Lines: 58
-
- higgins@fnalb.fnal.gov (Bill Higgins-- Beam Jockey) writes:
-
- >In article <63811@cup.portal.com>, Eric_S_Klien@cup.portal.com writes:
- >> Would it be possible to put something in near orbit over Nevada and
- >> attach tethers to it so that people could reach the object via
- >> elevators? I know it wouldn't be easy, but is there a way to pull
- >> this off?
-
- >Hmm. Interesting question. To first order: No, it's impossible, for two
- >reasons.
-
- >Let's examine your question again.
-
- >> Would it be possible to put something in near orbit over Nevada and
- >> attach tethers to it
-
- >You could hang over Nevada in a non-Keplerian orbit, that is, if you
- >were willing to thrust continuously. You can hire a helicopter pilot
- >to do this until her fuel runs low.
-
- >Bob Forward has proposed using high-performance solar sails to put
- >payloads into such orbits. I think there's a pop discussion of this
- >in his book *Future Magic*, and more technical stuff in various AIAA
- >papers. There's no obstacle in principle to this that I know of, but
- >the technology required (really light, really large, highly reflective
- >sails) is at least a couple of decades away.
-
- >If the altitude were low enough, the strength requirements on your
- >tether would go down, and it might really be buildable (given
- >staggering technology).
-
- One thing you forgot, Bill: Space fountains. Accelerate ferromagnetic(?)
- "hula hoops" electromagnetically, aiming them nearly straight up. Then
- decelerate them electromagnetically, transferring both momentum and
- electricity to the decelerator. This is itself a huge ring, sort of.
- Imagine a hollowed out cylinder, with two much smaller cylinders cut
- out of the remaining material, opposite each other. The hoops go up thru
- one side, where they are decelerated, giving an upward momentum boost to
- the huge cylinder, and with the power generated from this, they are
- accelerated downward on the other side (when they reached the top of the
- fountain, they were turned back down towards Earth), thus balancing the
- momentum transfer on both sides of the cylinder. STack a bunch of these,
- and voila! a space fountain. This was also studied by Forward, along with
- many others. As far as I can remember, it doesn't require any material
- advances. And the neat thing is, by working it properly, you can have
- a geosynchronous satellite above just about any point on Earth, up to any
- height. The power requirements are very large, of course (I don't remember
- exactly), but within reason. You can then also ride this up to space in
- a variety of fashions.
-
- "Far better it is to dare mighty things, to win glorious triumphs, even
- though checkered with failures, than to rank with those poor spirits who
- neither enjoy nor suffer much, because they live in the gray twilight that
- knows not victory nor defeat."
- - Theodore Roosevelt
- --
- "To be average scares the hell out of me." -- Anonymous
- Tom Nugent e-mail: tjn32113@uxa.cso.uiuc.edu
-