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SPACE ELEVATOR!!! XPRIZE TAKE NOTE! update!!!!!

Posted by: Rob Goldsmith - Tue Jun 29, 2004 4:05 pm
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SPACE ELEVATOR!!! XPRIZE TAKE NOTE! update!!!!! 
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Post SPACE ELEVATOR!!! XPRIZE TAKE NOTE! update!!!!!   Posted on: Tue Jun 29, 2004 4:05 pm
First of all read this guys!
http://www.space.com/businesstechnology ... 40629.html

Seems its realy got momentum, and what was mentioned that caught my attention was them mentionaing that it would be the new way to get to space cheap!!!!!!!! so people may think this will kill the private space industry but i see it helping it drastically!

So imagine with me for a sec' here! the huge lift moving up and down on this elevator, well now how much cheaper would it be for ships like SS1 to be attached to the elevator and flown from 62miles! no need for white knight designs anymore, simply start the engines from space! fire off from there in ss1 on a full fuel tank. The options are huge! if you could rent the elevator to ship goods then nasa or whoever would make the money to keep it running and there would be a boom in space. Like a station to the stars?
Who's with me

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Post    Posted on: Tue Jun 29, 2004 5:39 pm
There is no such thing as a "free lunch". Proponents of space elevators will find that out as soon as they try to take the concept from abstract designs on paper into a workable system.

Going to space is hard - that's why it is tempting for people to fantasize about weird stuff like cold fusion, anti-gravity, and space elevators instead of actually doign the hard work.

The X-prize group and the various competitors have nothing to worry about...

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Post    Posted on: Tue Jun 29, 2004 9:23 pm
Someone will build a space elevator someday unless it becomes cheaper (per pound) to launch other ways before one gets built.


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Post    Posted on: Sun Sep 12, 2004 4:58 pm
I see the space elevator as being the river-barge of space. It will be the cheapest way to get bulk goods to GEO, but beyond that it probably won't be used much in the long run as a personell transport. Takes to long to get up to 22,000 miles on an elevator. Assuming the elevator was able to climb 500mph, that's still almost two days. That's a lot of time sitting in a can, passing through Van Allen belts.


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Post    Posted on: Mon Sep 13, 2004 6:39 am
Concerning the realisation of the space elevator let's wait for the results of the competition for the climber-prize, the cable-prize and the energy-prize.

But there is one very important property of the elevator providing not only a technological breakthrough - or as JustMeKevin said a next evolutionary step - but a source of intensive use of the elevator for manned missions too: By using the extension of the elevator beyond the geostationary orbit up to an altitude of 100.000 km spacecrafts can be accelerated and launched to the planets without any consumption of propellant!

The climber is reusable - and everything whats transported by it too.

Do you see the new world of possibilities and opportunities?



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Post    Posted on: Mon Sep 13, 2004 1:24 pm
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By using the extension of the elevator beyond the geostationary orbit up to an altitude of 100.000 km spacecrafts can be accelerated and launched to the planets without any consumption of propellant!


Um, wouldn't that just put the elevator in a 100,000km orbit? HEO, I know, but not really escape velocity.


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Post    Posted on: Tue Sep 14, 2004 3:57 pm
Anything that has a circular orbit at 100,000 kilometers take much more than 1 day to orbit. But the top of the elevator is a faster "orbit", because the earth spins the whole elevator once per day. As a result of the faster orbit, you're pulling away from Earth because of centripetal force overcoming gravity. Force something to orbit faster; the object pulls away from the center of gravity. Eventually the speed is high enought to escape earth.

But, anything released from a space elevator before escape altitude will go into an elliptic orbit. (Sole exception is geostationary altitude, at which point, orbit will be circular). Anything released above geostationary orbit will have greater pull AWAY from earth but eventually gravity pulls it back, curving the object back down, resulting in an elliciptal orbit.

At some altitude (I remember it was 47,000km), the top of the elevator is already at escape velocity. When you're much higher at 100,000km, you got WAY MORE centripetal force than gravity, just like swinging a counterweight tied to a string above your head. Your object escapes Earth before it hits the apoapsis (highest point of elliptic orbit). The centripetal pull-away force is strong enough to be escape velocity at approximately 47,000km altitude on the elevator, That means it will never fall back to earth because it escapes earth before falling back, because the centripetal force of the spinning earth "SHOT-PUTTED" (olympic-style) the mass away from the planet, overwhelming gravity.

In this case, a space elevator is just like a mammoth shotput.

As a related note, this is exactly how you keep a flimsy ribbon or rope taut: A sufficient counterweight above geostationary orbit ensures that the whole space elevator stays standing!

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Post    Posted on: Thu Sep 16, 2004 8:36 am
Thats why its so tricky, the whole thing is under huge tension. It has esacpe velocity but is not escaping, and somethings got to hold on.

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Post    Posted on: Fri Sep 17, 2004 2:01 am
Mark Rejhon wrote:
In this case, a space elevator is just like a mammoth shotput.

As a related note, this is exactly how you keep a flimsy ribbon or rope taut: A sufficient counterweight above geostationary orbit ensures that the whole space elevator stays standing!


Not to rain on your parade, Mark, but for the tensions you're talking aobut, you'd basically have to have a cable the diameter of a small mountain. That and the Grand Canyon filled with lead for an anchor.

The tensions you're dealing with at that kind of altitudes and speeds are absolutely insane.

Although it's a really cool idea, that specific type of elevator is a long ways off. GEO elevators will come long before.

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Post    Posted on: Mon Sep 20, 2004 9:06 am
Please refer to Edwards's documents at the NIAC-site - there seem to be hints and proves that nanocarbontubes really fit to the tension. The elevator prize will cause increased research of that. Additionaly the tubes will be protected and strengthend by epoxy.

We should wait for he results of the elevator prize concerning the cable.



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Post    Posted on: Tue Oct 05, 2004 1:43 am
spacecowboy,

True for traditional materials, but potentially not really -- the unobtainium already exists -- it's called carbon nanotubes. Only 7 kilograms per kilometers for a space elevator ribbon capable of holding its own weight up;

The walmart-style yellow nylon-like rope that got demonstrated on Discovery TV channel as holding up 5 cars in an actual tests. This means the rope can hold about 500 to 1000 kilometers of itself before it breaks. Carbon nanotube ribbon would extend this to about 60,000 kilometers of itself with a large safety margin before it breaks. And don't forget suspension bridges... And don't forget the transatlantic cables... We've ALREADY chieved the tension of cable carrying >1000km of its own weight (imagine cable hanging a gigantic >1000km spool of itself, that tension is already achieved).

Yes, the GEO elevators will come long before, but they all have to be 60,000 kilometers anyway. So it's pointless to ignore the fact that escape velocity happens only a little more than 10,000km above geostationary orbit.

It's impossible to have a GEO elevator of the cable/ribbon type WITHOUT counterweight above the GEO orbit.

THEREFORE, ANY GEO elevator is ALSO capable of being a space elevator to bring you to escape velocity, because anybody deploying a GEO elevator will be at least 47,000km long just due to the mere requirement of counterweight ABOVE the geostationary orbit which is approximately 35,786 kilometers. Escape velocity is a MERE 12,000 kilometers higher up on the space elevator (which will already be there by necessity of a counterweight needing to exist above geostationary orbit to keep the cable taut)

And by the way, the escape velocity portion is UNDER LESS TENSION than the cable just right below geostationary orbit! Tension is NOT A PROBLEM at the ends of the cable -- i.e. top of the escape velocity cable, or at the surface of Earth. That's where the least tension will be. It's the GEOSTATIONARY portion of the cable that is the BIG PROBLEM -- geostationary happens to be the point of maximum tension in a space elevator cable.

There's no weight at geostationary orbit, but there maximum and equal amounts of immense tension right at the cable right below geostationary, and right above geostationary. Tension decreases as you go away from geostaionary. There must be EQUAL PULL UPWARDS AND DOWNARDS at the geostationary anchor, otherwise, you're pulling out of geostationary.

Again, I remind, counterweight ABOVE geostationary is a NECESSITY to keep the calbe taut -- therefore to have little mass above geostationary, ANY GEO elevator will also have escape velocity ability, (unless you want an asteroid or mammoth mass to compensate for the little weight that any mass has slightly above geostationary -- you want to go at least about 20,000 kilometers above GEO to use a small counterweight that can be built simply of dead climbers rather than an asteroid).

That's why it's not econimically pratical to build ANY GEO ELEVATOR that's LESS than approximately 60,000 kilometers long, and THEREFORE, with escape being at 47,000 kilometers, THEREFORE there will be escape velocity ability in the first GEO space elevator from Planet Earth. They could choose to ignore this, however, there's no difference in tension at the base above and below geostationary, and the tension decreases as you go away (up or down) away from geostationary.

And I requote a post of my previous post:
Quote:
[...snip...]Don't forget these newer space elevators concepts are simply a massive super-sizing of a simple children's toy :) -- a ball tied to a rope. Space elevators are NOT Earth-standing structures. Nothing needs to hold up the elevator -- it's swung taut simply by the spinning earth

Common children's toy -- a ball tied to a rope. Swing it around, and you've demonstrated how the space elevator stays taut. The rotating Earth keeps the line stretched. As long as there's enough weight above the geostationary orbit, the centripetal force OVERCOMES gravity!

You do have to concede that the space elevator is more realistic now with the carbon nanotube "ribbon" concept. There's a lot of staggering engineering obstacles.

The excitement over one, would probably be similiar to the excitement from the 1858 transatlantic telegraph cable. (The 1866 cables were far more successful, though). Thousands of tons of continuous cable, all had to be rolled out flawlessly from a ship, without the cable breaking. These cables were extremely heavy (old thick impure copper, thick tar and early rubber-like substances called "gutta percha"; which was also used for 19th century golf balls as well). The 1857 attempt to roll the cable caused repeated snaps. Imagine several miles of cable pulling down on the ship, hanging diagonally, before it hit the ocean floor. Although underwater, you have to keep in mind that these cables were mostly metal and heavy tar-like substances, which meant immense amount of weight suspended as the cable-laying ship went across the Atlantic. These cables had to be among the strongest cables about 150 years ago, just because several miles

Today. Now we have cables that you can buy at stores (Home Depot, Walmart), that that can hang by its own weight by hundreds or thousands of miles hanging with enough room leftover to lift a small capsule. But that's not long enough for a space elevator. You can already use Home Depot nylon-like rope for a space elevator on many small bodies (i.e. for going into orbit around asteroids), it's strong enough. Today, household cable can be suspended by hundreds of miles -- the yellow cable you buy from Walmart or Home Depot (of course, you'd need weatherproofing and take into factor of water absorption, and other Murphy's Law factors). These cables are so light, that it's only a few pounds per mile (only a kilograms per kilometer) and you've seen some of those hold up the weight of a car (thousands of kilograms or thousands of pounds). A Discovery show showed some similiar cable holding up a whopping 5 cars. So these cables can easily be suspended in the 3-figure range (and the stronger cables, likely developed for the military, in the low 1000's range - the 4-figure range!), if you had something that high-up to suspend from. (Too bad the geostationary orbit isn't only 1000 kilometers above the surface of Earth!)

It's like a rope tied to a ball -- the rotating of the planet or body "swings" the counterweight away from the body. All you need is a big enough counterweight above the geostationary orbit, so that you've got "pull" that exceeds gravity, simply caused by the spin of the planetary body (i.e. Earth).

A space elevator would be very easy on an asteroid surface because asteriods are low gravity, and we even already have rope that can make a moon elevator already. But it's fiendishly difficult for Planet Earth -- it's only recently that the 'unobtainium' was found (Carbon nanotubes!) that just suddenly made space elevators very possible.

NOW....A pratical space elevator, requires 5-figures worth of cable or ribbon, something like 60,000 kilometers. Ignore past space elevator concepts like those found in books and in the 1980's and before which was tall structures or similiar, these concepts are unrealistic.

The other problems may prevent the space elevator from going up, but you do have to concede that it's a hell lot more realistic now.
[...snip...]

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Post    Posted on: Tue Oct 05, 2004 3:37 am
I'm going to side with Bad_Astra on this. While I firmly believe the space elevator will become a reality in 10 to 20 years, provided there's no world wide economic depression or something similar, I think the trip time will make it undesireable for passengers. Maybe a second generation elevator that lifts entire mini hotels that are well shielded and enjoyable for a weeks stay or so. I think there will always be rocket flight simply due to the time factors involved. The other promising outer edge launch systems aren't much better, JP Aerospace's Airship to Orbit is also pretty slow, gas gun/catapults to intense and practical laser launch ships possibly even more unlikely that the space elevator. Although I guess the climbers could be considered a type of laser launch vehicle.


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Post    Posted on: Thu Mar 10, 2005 7:13 pm
www.liftport.com


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Post    Posted on: Wed Apr 27, 2005 2:02 pm
publiusr wrote:
www.liftport.com

and to support that brief (yet highly informative) post on this subject, here is a news release from today (27/4/05) concerning the imminent fabrication of actual hardware by said company/group ...

http://cbs2.com/water/watercooler_story_116173449.html

Now can someone remind me what this thread is doing in the "Xprize in General" Forum?

DKH

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Last edited by Dr_Keith_H on Wed Apr 27, 2005 3:06 pm, edited 1 time in total.



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Post    Posted on: Wed Apr 27, 2005 2:10 pm
Hello, Dr_Keith_H,

I recently moved a large number of threads to section they seemed to fit into better.

I left this thread in this section because I mostly used the initial post of the threads as the criterion to move it or to move it not.

The initial post of this thread here now consideres space elevators, elevator prizes and prizes for technologies that could be used for elevators as prizes competing to the XPRIZE.

That's the reason why this thread fits into this section here from my point of view.

This means that I would like if each one posting here would concentrate on impacts of elevator etc. prizes on XPRIZE competitions.

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