http://www.space.com/businesstechnology/technology/space_elevator_020327
-1.html
Awesome. I can't wait. In fact, I want to buy a ticket now....
For other reading:
Excellent book by Robert Sheffield called Web Between Worlds (though his
attachment method was questionable)
2300AD (Traveller 2300): They had beanstalks and also covered the impact
(literally) of one that is unleashed on the planet it services.
> Tomb wrote:
> Awesome. I can't wait. In fact, I want to buy a ticket now....
Oh, yeah. I've been WAITING for this.
> For other reading:
Would you say he didn't know jack about beanstalks?
I believe there's one in Friday by Heinlein as well (though that is by no
means an endorsement of the book). I could have misread it though.
> 2300AD (Traveller 2300): They had beanstalks and also covered the
I'm assuming you meant of the tether comes loose from it's space end. I'm
curious to see a story/scenario where it comes detached at the earth end
of
the tether - talk about an olympic hammer throw. ;-)
3B^2
> I believe there's one in Friday by Heinlein as well (though that is
There is at least one--Nairobi IIRC.
> On Wed, 27 Mar 2002, Laserlight wrote:
> > I believe there's one in Friday by Heinlein as well (though that is
I'm pretty sure it's Nairobi; the scene occurs right at the beginning of the
book. 'Friday' suffers from a totally goofy ending and the usual
Heinlein-esque oddities, but it's the closest he ever got to cyberpunk,
and a lot more dystopian than most of his stuff. With the caveats I've
mentioned, a very good book.
Lots of FMAS or SG2 inspiration in it, actually. Our heroine is a
martial-arts/weapons expert spy/spec ops type; and there's a couple of
fights & assaults mentioned in enough detail to provide scenario fodder.
> > There is at least one--Nairobi IIRC.
Quito too, now that I think of it.
> I'm pretty sure it's Nairobi; the scene occurs right at the
Not when compared to Number of the Beast or a couple of others.
> Lots of FMAS or SG2 inspiration in it, actually.
well...there's the assault on the farm house. Nothing else that would do for
SG that I recall although you could put a merc company on a riverboat and see
wo's bright enough to wear a life jacket.
I don't know if anyone mentioned this yet or not, but you should really take a
look at:
http://flightprojects.msfc.nasa.gov/fd02_elev.html
Great wallpaper, too!
On Wed, 27 Mar 2002, Brian Bilderback begged to be Narn'd by writing:
> Tomb wrote:
***whack***whack... etc... :>
> >2300AD (Traveller 2300): They had beanstalks and also covered the
I'm
> curious to see a story/scenario where it comes detached at the earth
See Kim Stanley Robinson's Red/Green/Blue Mars trilogy. Incredible
books, and there's a space elevator collapse in either the first or second
book. The thing is so long it wraps right around Mars (at least once, possibly
twice...). One of hte characters notes that Mars now as a big black line
marking the equator, just like he thought Earth had from looking at the globe
as a little kid!
Seeing as we're in a book-recommending mood this week, do read Red
Mars/Green Mars/Blue Mars. No combat worth mentioning, just lots of
people stuff mixed with a healthy dose of cool tech stuff. Excellent books.
In Robinson's Red Mars saga someone does manage to drop a beanstalk - it
wraps around Mars a coupla times. I'd love to see that done by a good CGI
studio.
> Brian Bilderback wrote:
> I'm assuming you meant of the tether comes loose from it's space end.
> I'm curious to see a story/scenario where it comes detached at the
I'll chip on this series again. It's a political/social/ecological
story. I'd consider Mars to be the main character, and I will warn that long
odes to the martian landcsape abound, however it worked for me.
A lot of trilogies wrap up in an unsatifying manner. This series ends very
well. Then the 4th book, The Martians adds a very elegant coda to the series.
It
> Brian Burger wrote:
> On Wed, 27 Mar 2002, Brian Bilderback begged to be Narn'd by writing:
I'm
> curious to see a story/scenario where it comes detached at the earth
> On Wed, Mar 27, 2002 at 06:02:02PM -0500, Tomb wrote:
Charles Sheffield. And it's, um, not entirely tolerant of failures at the last
moment, I agree...
> Michael Llaneza wrote:
> In Robinson's Red Mars saga someone does manage to drop a beanstalk -
Someone else mentioned this one. Dounds like a very good story. But my
curiosity was not about dropping a beanstalk, it was about letting one go
from the bottom - the opposite effect.
3B^2
> Someone else mentioned this one. Dounds like a very good
This happens as a planned action in the 2300AD sourcebook Invasion, to prevent
the Kafers from dropping it. I can't recall much about what happened to the
Beanstalk after separation and most of what I can remember was about the
powerloss due to the fact that the Beanstalk was the major solar power
collector. On the otherhand I don't have the books immediately to hand.
In a message dated 3/28/02 8:26:53 AM Central Standard Time,
> bbilderback@hotmail.com writes:
> Someone else mentioned this one. Dounds like a very good story. But
A beanstal top would be geo-stationary, would it not. It would not have
much angular momentum and would at most drift away and be recoverable for some
time. The 2300 AD universe has a beanstalk detached during a planetary
assault - to keep it from being dropped upon the planet (Kafer war
scenario pack).
> On 28-Mar-02 at 09:37, Popeyesays@aol.com (Popeyesays@aol.com) wrote:
But my
> > curiosity was not about dropping a beanstalk, it was about letting
The discussions I have seen on been stalks go something like this.
1. Put a satellite in geo-stationary orbit.
2. Simultaneously extend a fiber down and a fiber up. 3. Anchor the down fiber
to the ground. 4. Extend the up fiber a bit more and put weight on it.
The trick is the whole system only stays in its' current orbit because it is
anchored. When you cut it free it is going to fly off into space.
> Popeyesays writes:
> A beanstal top would be geo-stationary, would it not. It would not have
> much
Good point.
> Popeyesays writes:
> A beanstalk top would be geo-stationary, would it not. It would not
Depends on where it's cut, doesn't it? Imagine a bomb going off halfway up.
Very unhealthy to be on the ground where the lower half hits. I don't know
where the upper half would go but if it was in balance before it was cut, I
wouldn't think it would still be balanced afterwards
On 28-Mar-02 at 11:56, laserlight@quixnet.net (laserlight@quixnet.net)
wrote:
> Popeyesays writes:
It should never be in balance. If it's in balance when I put my payload on the
center of mass shifts down and it assumes another orbit. The thought of the
orbital mechanics makes my head hurt.
For instance...
To lower something in orbit you slow it down. (Yes, its' angular velocity
increases but its' absolute velocity decreases.) If I slow down the cable
though it is going to start moving relative to the sattelite and make it spin.
I'm guessing you ignore the normal "rules" and accelerate the end of the cable
directly at the surface. It's just when I imagine this I keep seeing integral
trees.
> Popeyesays wrote:
> A beanstalk top would be geo-stationary, would it not. It would not
I thought about this some more, and here's what I realized:
When dealing with an untethered orbiting satellite, this is true. But not
necessarily for a tethered beanstalk end. Here's why:
Remember the old image of a phonograph. The farther from a certain point you
are, the greater your linear speed must be to maintain the same rate of
rotation (rewvolution?). The opposite is true for orbiting: the greater the
distance from the center of mass, the LESS velocity needed to maintain orbit.
So the farther a satellite is from the earth, the slower it needs to go to
maintain orbit, but the faster it needs to go to stay directly above
any given point on the surface. Geostationary/geosynchronous orbits are
maintained at the distance at which these two velocities match (on a graphof
velocities, at the point where the two lines cross). If you set the end of a
beanstalk at that altitude, sure, if the module on the end ot the stalk were
detatched, it would probably maintain orbit. But if it extends further out,
two things will happen: the beanstalk is going to be pulling it along at
greater velocities in order to keep up with the base point on the surface, and
the necessary orbital velocity will DECREASE. That means a
stalk end set further out will be tugging at it's stalk, since it will
probably be at escape velocities. if untethered, it should go flinging away.
Or am I missing something?
3B^2
No, you are correct. And this is necessary to maintain tention on the
beanstalk. If you put the end mass at the orbital velocity point, you will
pull the whole thing down every time you send up a mass (as you pull it into a
slightly lower, unstable, orbit). Therefore the angular force of the endmass
has to be greater than the pull of gravity on the end mass, the beanstalk, and
any payload (including transport) that you send up the stalk. Or at least that
is how I understand it.
> Brian K Bell wrote:
> No, you are correct. And this is necessary to maintain tention on the
> into
That's how it struck me as well.
3B^2
Attaching a mass to send up doesn't necessarily have to tug the whole thing
down either. A couple of solutions are to have the same mass coming down as
going up (if the top end were in orbit near an asteroid being mined and ore
was shipped down), or to have the counterweight at the top with an adjustable
length tether. When you attach a elevator at the bottom, let the counterweight
out a bit and reel it in as your elevator climbs to the center of mass.
Another consideration is how much is an elevator going to affect the whole
system? This thing is going to be HUGE, and have a lot of mass. 50 tons of
mass a day may only be a small perturbation force compared to even things like
wind. The gravity from the moon and sun are also going to be pretty hefty
perturbations on its stability as well, just think what they do to the oceans
every day.
For a couple of additional references:
http://www.aleph.se/Trans/Tech/Megascale/tower.txt
http://www.aleph.se/Trans/Tech/Megascale
Randy Wolfmeyer
> On Thu, 28 Mar 2002, Bell, Brian K (Contractor) wrote:
> No, you are correct. And this is necessary to maintain tention on the
From: "Brian Bilderback" <bbilderback@hotmail.com>
> Popeyesays wrote:
Umm... not quite.
The concept that I'm most interested in consists of unanchored beanstalks.
These rotate (due to tidal forces). They can be at virtually any altitude.
Provided you keep on putting a tadge more energy into them (by ferrying
material into the gravity well) than you take out, their orbits won't decay.
The best thing about them is that they can be made right now with existing
> From: "Alan and Carmel Brain" <aebrain@webone.com.au>
> The concept that I'm most interested in consists of unanchored
All of which is a good point and very interesting, but not germaine to the
original question I aksed, "What would happen if an ANCHORED Beanstalk's end
mass got UNtethered - it seems the correct answer would be, "depends."
3B^2