Subject:
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Re: NASA IS GOING BACK BABY
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Newsgroups:
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lugnet.space
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Date:
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Wed, 7 Feb 2007 23:53:02 GMT
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Viewed:
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5785 times
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In lugnet.space, Brian Davis wrote:
> In lugnet.space, Mike Petrucelli wrote:
>
> > > It's that it's not *cost effective* to do it [with rockets].
> >
> > I would add *yet* to that.
>
> The problem is rockets use reaction mass, and need to carry it along, so the
> rocket equation enters into everything you do. And honestly a rocket is not a
> very good way to use the energy: you have to launch at high speed (rocket
> equation again), which costs you... a lot, actually... in terms of air
> "firction". There's a reason rockets go up, and it's to get out of that lousy,
> lossy atmosphere before you start trying to build up any significant speed (LEO
> orbital velocity = Mach 25 or so. Ouch).
On the other hand "Space Ship One" already surpassed NASA in efficiency with the
use of a "carrier plane" to get a much higher start. Building a plane
specifically designed for high altitude super sonic launching of "rocket ships"
is one easy way of making it more efficient already. That would make another
good MOC. :-)
>
> Space elevators and tethers have a big advantage in that energy can be delivered
> in a cheap (semi-primary) way (electrical), and the "reaction mass" used doesn't
> have to be carried along (the entire Earth). Even better, for something like an
> orbital or "space" elevator, a significant part of your energy requirements are
> *free*, tapped out of the rotational energy of the Earth - you *don't* have to
> supply it.
Eventually I can see tethers being the preferred method of getting there but the
inital construction would really be far easier to "drop" the tether down to
earth. The first one at least would still rely almost exclusively on "rocket
ships".
> > I don't know a town layout on the floor with a "space elevator"
> > to a manufacturing platform way up on a shelf could make a
> > really cool albeit parts intensive MOC.
>
> Well, one thing you could do would be a model of the base of a space elevator.
> The mopst likely one at this point would be something like the ones based on a
> carbon-fiber "ribbon", where the cable itself would be absolutely invisible at
> any MOC scale (current plans are for the ribbon to be perhaps 10 cm across or
> less, with a thickness measured in *microns*... and use, that could be used to
> haul loads to orbit, and support itself. Impressive). A model of the proposed
> base would be interesting (current desings are based on the SeaLaunch platform,
> so it looks somewhat like an off-shore floating oil rig without the derrick).
>
> From fiction, a lot of authors have proposed that the base of the tether in
> particular grows into a town of some size, piling up around the tether
> connection point. That could make an interesting MOC, sort of a furturistic city
> on top of a mountain (Kilimangaro (sp)?), forming a cone city tapering to the
> nearly infinite-appearing thin cable at the center.
>
> I also remember vividly a scene from Pellegrino's "The Killing Star" of an
> Earth-based orbital tower that had essentially grown into a 23,000 mile tall
> mega-city, with residences, malls, industries, etc all plaster along the sides.
> Not likely, but a beautiful image... just before is was vaporised in a fraction
> of a second by an R-bombing attack from another star, but that's a different
> story :-).
All nifty ideas but I prefer to see the station and the town/city, even though
the scale would be completly off. I guess that why snow capped mountain MOCs
with coastlines at the bottom don't bother me, even though the scale is usually
only a hundered meters or so. That would be even more wacky with a tethered
space station but it would be fun to look at and/or build.
-Mike Petrucelli
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Message has 1 Reply:
 | | Re: NASA IS GOING BACK BABY
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| (...) Yep, but it came no where *near* orbital velocity - about a factor of 30 to low in energy. I agree, it's a nice mechanism to get away from the atmosphere problem, but so do balloons (for a far lower cost, actually). no offense to Space Ship (...) (18 years ago, 8-Feb-07, to lugnet.space)
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Message is in Reply To:
| | Re: NASA IS GOING BACK BABY
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| (...) The problem is rockets use reaction mass, and need to carry it along, so the rocket equation enters into everything you do. And honestly a rocket is not a very good way to use the energy: you have to launch at high speed (rocket equation (...) (18 years ago, 6-Feb-07, to lugnet.space)
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