Do they need solar panels on the climber? Is it possible to just send power up the cable?

Ian-
The short answer is no.
The elevator will need the same amount of energy to climb the cable regardless where that energy comes from. Solar panels on the elevator itself are the best way to get that energy. The two most obvious alternatives to solar panels on the climber are fueling the climber (gasoline, hydrogen, ect), or transmitting the power from the ground (which could be generated any number of ways. In both cases, the biggest problem is in the weight. The amount of fuel the climber would require would be significant, I am guessing somewhere in the tens of thousands of gallons.
In the case of transmitting power, you would need a conductive cable. That would be a metal cable. In order to transmit the power needed to move the elevator, that cable would need to be fairly thick. Even having a metal cable as thin as speaker wire would snap under its own weight at the length required for the elevator.
So no, it is not possible to send power up the cable.

I'd hope they would find a way to trasmit power to the lift. I'd think they could use the carbon cable to support an electrical delivery cable without the metal snapping under its own weight as it were. It's most certainly better to add weight to the carbon cable instead of the lift.

I have three questions am unable to answer, perhaps a physicist may shed some light.
1)Assuming the ultra light carbon nanotubes weighs x kilos per mile, how shall they get x*62000 kilos to space so as to start drawing the cable downward till ground (assuming they opt to do it this way). Lets not opt for helium balloon to lift this cable as balloons can only go a few miles before they loose their effectiveness due to ambient air thinness.
2)This cable will pass the ionosphere on it's way downwards, assuming the cable will conduct electricity as it is made out of carbon, this cable may provide a vehicle for the vast number of electrons found here to reach the lower levels of the atmosphere where these free ions may be captured by positive ions.
3)How will the cable void being the vehicle of choice for electron transfer between ground and the clouds (and between lower clouds and higher clouds) in stormy weather, will the cable sustain such loads of electrical current. Lightning is usually brought about by such activity.

Allan.

NikoT: Carbon nanotubes can be excellent conductors, so a power cable would not need to be made of metal.

Allan: In answer to your first question, one posited plan is to haul up a very thin cable, and use that to haul up a more substantial one (and so forth if necessary).

I think positioning of the cable anchor close to the equator is the main proposed way of minimizing lightning strikes; but you're right, there's no complete answer to that yet. Perhaps some sort of nonconductive insulation on the vulnerable parts of the fiber would be possible.

If the cable conducts electricity this seems like a much better way to ferry power from solar arrays in space than microwaves that could potentially damage where they hit.

if space elevators became fairly common, couldn't there be a potential problem with travel by air (planes, helicopters, etc.)? or would they primarily exist on a temporary basis? there might be something i'm missing here, but it doesn't sound completely practical.

What about reentry? Will it be travelling slow enough to not build up enough friction to make it an issue?

they way to power the elevator is with a stationary laser at the base of the nanowires. since lasers travel in a strait line, it will always hit the solar panels unless interrupted by an aircraft, asteroid ect.
reentry... possible to have a heat sheild, but that might be tricky.

(plus the laser would have to be big with like a million watt diode) [exxaggeration may have been implied]

to strictbusinees14, aircraft strikes are not impossible but the airspace around it would be controlled much like the airspace around military bases, forest fires and other special exceptions. Pilots need clearance to enter these zones but potential terrorist attacks could still happen although I imagine the military would have a close eye on it.
Thank you Paul Adams, I was pretty sure carbon nanotubes were almost perfect conductors, perhaps though it makes a difference if the tube is not continuous from end to end. They don't say if the nanotubes would be woven together from shorter strands or if they could create a continuous tube that would span the entire distance. From my understanding they haven't been able to create tube of significant length.

In fact, when Boeing built the first 787, one of the concerns was how to handle lightning strikes.

The problem is that even though the carbon construction fiber is relatively non-conductive (as compared to a "true conductor"), there is enough conduction as a result of the "other" components that the heat generated as a result of a massive voltage/amperage multi-pulsed load (characteristic of lightning strikes) would cause the structure would heat at the strike contact point and possibly vaporize some of the carbon and form ionic carbon dioxide (which is a much better conductor than the carbon itself). The solution was to embed a copper foil mesh just under the surface of the outer carbon layer and provide an "entry/exit" pathway for the strike. One other characteristic of very high voltage events is that the electricity is carried as a "skin conduction on the surface" (current only flows through a very thin layer - the "corona effect" is what it's called). The intent was to give a "through path" for the power to pass around the outside of the aircraft and re-enter the atmosphere for its trip either "up" or "down" ("to" or "from" the cloud to "earth" - meaning a different "potential" - as applicable)

I can see that type of "elevator" construction "possible", but the weight penalty could get excessive - remember - everything needs to be put "up" there in the first place. the copper would be, in effect, a "parasite" (necessary, but not as a structural load carrying piece)

BTW - There's a reason lightning rods are attached to grounds with #10 (smallest I've seen) copper wires - the heat generated as a result of a strike will heat the wire quite a bit. It's even possible to "burst" copper wire (literally "explode" - vaporize - say a #30 wire) by applying a pulse of sufficiently high CURRENT. All the wire burst experiments I've ever seen don't have anywhere NEAR the power of a lightning strike, though - "millions" of amps - plus the wire burst is a "single electrical discharge" event - no small amount of electrical power, but nowhere close to an atmospheric lightning discharge

Ridiculous! the number of variables and potential problems to arise make this an impractical, un-logical pipe dream. The effects of wind current, wind storms, space debris, solar flares, thermal loading, expansion and contraction, thickness variations, lightening, and effectively shorting the ionosphere to ground will put the price tag high enough to bail out Wall Street!

Don't be ridiculous yourself. The cost of this technology would be irrelevant. The first country to develop such an elevator will effectively control access to space. Talk about priceless. Of course there are hurdles to overcome. Every great technological accomplishment in history has been viewed as impossible and preposterous by most people. The visionaries view impossibility as irrelevant and cost is just another hurdle.

For you technos, consider that the power used to climb the thread could be mostly recovered from gravity on the way back down. There would be some loss that could be recharged at the ground.

Hey Guys and Gals,

Just a thought, a lot of you gave your ideas regarding the space elevator's source of energy for going up or down. What if it would be similar to an ordinary elevator - that is - place a counterweight at the top that is heavier than the "things" that will be loaded. It's locked in place up there, then when it's time to put some cargo "up there", the "locks" could be released then let gravity do the work - the counterweight goes down and the "cargo" goes up.

The only problem that I see is getting the counterweight back up again. Well, at least it could help in lowering down the "power" requirements for this thing. I know it sounds like a crazy idea given that everything has to be super-strong because of the "stress" and the Gs involved. But that's just one of those crazy ideas that came to my mind.

By the way, it's now 2008 and isn't it about time for our Space Odyssey?

Here's the thing about powering the climbers. They are most likely to be powered by power beaming. This technology is in development and works like this. You convert electricity to microwave radiation in one place and from there you beam it to a receptor which converts the microwave radiation back to electricity. That seems to be the most promising technology for powering the climbers. Power beaming is also likely to be among the first commercial uses of space aside from communications. Solar power collected with greater efficiency in outer space will be beamed down to earth to provide clean, essentially infinitely renewable energy.

Somebody mentioned lightning strikes. Lightning strikes are a potential problem, but the idea of using some kind of lightning rod to protect the tether is not so far-fetched. While I'm not certain of the highest altitude occurrence of electrical storms, it is inside the atmosphere, so the added weight from a lightning rod would only affect, at most, the bottom 80 miles of the 62000 mile tether. It would likely not affect the strength requirements of the tether all that much.

As for airplanes, the tether would not be put anywhere close to major air traffic routes, and navigational systems can easily steer airplanes clear of it.

Of course there is a lot to overcome before a space elevator can become a reality. We need a higher strength tether material. We need to improve power beaming. We need climbers that can either ascend rapidly, or slowly but with large payloads. Despite these challenges the benefits of a space elevator are enormous. If it can really be done for only $10 billion, it would be a fire sale price tag.

Carbon nanotubes are classified as metallic because of their molecular structure and can carry an electrical density 1000 times that of copper or silver, not to beat a dead horse, but again why then can't we exclude any copper wire conductor and send power straight up the carbon nanotubes while also using the same tubes as the load carrying cable?

I see how using power beams can work but they are very inefficient, if they weren't then we would use them all the time for power transmission.

I'm just throwing this out there, but if lightning strikes would be so common then how about channelling that energy into a large heat sink like a large tank of water and use the hot water to heat a refrigerant medium that would flash off to spin a generator? Then we could harness lightning with a massive array of space elevators and conquer the world AHAHAHAHAHAHAHAHA! Sorry it's time for my medication again.

if you have read on it at all you will find out the plan on useing lasers as shown on the picture to send soloar energy up to the lift in the spectrum that solorpanles operate best at. sorry about the spelling to lazzy to spell check =p

if you have read on it at all you will find out the plan on useing lasers as shown on the picture to send soloar energy up to the lift in the spectrum that solorpanles operate best at. sorry about the spelling to lazzy to spell check =p

And if you had seen the results of university competitions to harness that energy with a climber then you would know that they barely convert any of that energy at all.

It is possible but inefficient.

Being a conductive ribbon, spinning around the earth's magnetic field, wouldn't it be possible to generate electricity on it's own? If the cable was actually a loop, then I would think it would produce a sizable electric current. For example, the ribbon could be two ribbons with an insulator inbetween. A switch at each end of the ribbon would hold one end open, while the other was closed. Contacts on the climber would conduct from each side of the ribbon, closing the circuit. The solar winds are holding the magnetic lines of force around the earth, perpendicular to the sun. The loop of this conductive ribbon would be spinning through the lines, making it a giant generator. Remember the shuttle experiment a few years ago?

The ribbon doesn't actually move through much of the earths magnetic field so it would generate very little electricity. Since the elevator has to be in geosynchronous orbit, the tether and the earth's magnetic field rotate at the same rate.

Somebody mentioned sending electricity up and down the tether. I think that would be difficult due to the tethers length. 62,000 miles makes for a lot of resistance, even with carbon nanotubes which have very low resistance. Also, it's my understanding that the resistance is very low from one end of one tube to the other end of the same tube, but that resistance from one tube to another tube may be somewhat higher. This is because of things like the arrangement of the carbon in the nanotube, i.e. its geometry, and the resistance in whatever epoxy or other compound is used to hold the tubes together.

Aw cmon evey1 knows its just bs......we have better things to worry about.

Um, no everyone does not "know" this is bs. All your comments certainly are though.
I think it's something that needs a lot more research and development, but through years and years of learning it might be possible. Kind of like your potential normal kid.

Not all my comments are tough.

But ty anyway

The Tether will be thicker on the Earth surface than at the counterweight. As the car goes up the, counterweight loses energy and will come down. When a car comes down the counterweight goes back "up". The mass of the counterweight determines how much weight the Tether will handle.

If a plane runs into the Tether, then the Tether will stay put, it's in geosynchronous orbit(GEO). Plus its very strong.

A Tether moving though the Magnetic Field will generate Electricity, An elevator would be able to generate some because the magnetic field fluctuates.

You could put solar cells every so often on the tether once it is out of the atmosphere.

To install the Tether a rocket would carry a "spool" of cable up to space and then the spool would send a "wire" down at the same time it sends the counterweight up.

The space shuttle costs $10,000 a pound.
The space elevator costs $200 a pound.

At 1000 mph it would take 26 hours to get to GEO

As Author C Clarke said "When your at GEO your half way to everywhere!"

Engineers look at Delta V to see how much energy it takes to go to another planet or a moon. Just getting to Geo is close to one half the Delta V it takes to get to any other place in our solar system.

A great place to start is at tethers.com

What about space debre and other satellites.

-THE KID

Won't the solar winds tear up the elevator?

No energy beams! If I had anything to do with this elevator, i.e. if I was a passenger or had cargo on it I would not want high energy microwaves or lasers pointing at me in the climber or anywhere near the cable. Can you imagine the cable being cut by its own power system?

-I believe Lightning happens mostly in the lowest part of the atmosphere.

-There are of spacecraft, satellites and and space junk in low earth orbit to be concerned about. The military can't stop that.

-The cable wouldn't be a straight line: Low level winds and the jet stream will affect the cable and the climber at higher attitudes. Solar panels would act like wind sails. The capsule would need to be streamlined like an aircraft.

The tether 'could' be a loop, rotating the loop with an electric motor at the bottom.

Cargo containers could just latch on for the ride up, detach, unload and load for the return trip.

Multiple containers, could be on the way up and down at the same time, balancing the load.

Make that SHOULD be a loop...

To generate a current, you need motion through a magnetic field, that would include, the linear motion of a loop in both directions.

The tendency of high frequency AC, to travel to the outside of the conductor is "skin effect", but the linear motion would produce direct current. DC.

Geosync orbit is 35786 km which would require a loop length of ~72 km.

The big problem would be tidal force in that the loop would be under tremendous tidal stress.

One way or the other, move away from the equator, because if it snapped it would wrap around the earth. It's ends would hit the earth, at a very significant impact speed and energy. (a stonger than steel bullwhip?)

We live in amazing times...

By the way, microwaves beamed in from the communications sats in the same orbit have the footprint of 1/4 of the u.s.
Microwaves are anything but coherent, and light just doesn't have the power yet.

Chipper Smoltz, docjohn52 and I are thinking alike: A moving loop seems like the way to go. It could be powered by a ground based electric motor possibly augmented by a solar powered electric motor at the top.