Question How do you get a spacecraft up a space-elevator?

[Stormloop]

So the space-elevator is a not realised concept in which you make an elevayor to several kilometers height in lower atmospheres, with the reasoning that launcjing a rocket from there would require way less fuel. Now ive been wondering how you would get the spacecraft up to the top? Do you use a winch and take days? A separate elevator and... take days and ofcourse a lot of electricity? I understand tjis is still less than the fuel to get up to this height normally but i feel like im missing something here.

 

[Stormloop]

Please do not mind the numerous typing mistakes, this was on a mobile and im everything but good at typing on one

 

[YetAnotherBob]

The plans I've seen are that the elevator cars climb up the cable. They need some power source from above or below for this. Generally lasers or masers are considered. The cable is anchored at the top and the bottom. The bottom is anchored to the Earth, any large chunk of bedrock will do. The top has some weight out past geosynchronous orbit. So counterweight isn't holding the cable up. The cable is holding the counterweight down.
Climbing up the cable then is a matter of crawling up from the ground. Transit times I've seen vary from six to eight hours to a couple of weeks. It really depends on how fast the climber can climb. It's climbing a bit over thirty five thousand kilometers after all.
If you don't go that far, you're not at an orbital velocity.
Time for this is around three weeks if you are climbing at 60 KPH. It's around 17 hours if your climber can climb at around 2000 KPH. Wheeled vehicles have been used for most tests. They can make the former speed. Magnetic levitated vehicles can make the latter.
Given the climbing times, most plans have multiple cables called for. There will be up cables and down cables. The cable has to be able to support both itself and the total weight of cargo and transport on it, plus whatever tension is created by the counterweight.
It's an interesting engineering problem.
We don't have a good material yet for making the cable. The best so far is some plastic coated carbon nanotube rope. I haven't seen any yet in lengths longer than a few centimeters. The Japanese are working on it. They claim to be able to make lengths of up to a kilometer. That may be marketing speaking however.
But the lengths needed are more like fifty thousand kilometers per cable however. That's why nobody has tried yet to actually build one. We simply can't do it yet. It's getting closer to possible however.
Kevlar would work fine for the Moon or perhaps Mars. Steel is possible, but the steel cables for the Earth would be literally thousands of kilometers thick at the top. Not really doable.
There are other problems as well. Those include dealing with meteorites, debris collision in orbit, vibration induced by atmospheric winds, power transfer, and flammability issues.All of these seem solvable, but it's not an easy problem.

 

[Dwight_A.]

The plans I've seen are that the elevator cars climb up the cable. They need some power source from above or below for this. Generally lasers or masers are considered. The cable is anchored at the top and the bottom. The bottom is anchored to the Earth, any large chunk of bedrock will do. The top has some weight out past geosynchronous orbit. So counterweight isn't holding the cable up. The cable is holding the counterweight down.
Climbing up the cable then is a matter of crawling up from the ground. Transit times I've seen vary from six to eight hours to a couple of weeks. It really depends on how fast the climber can climb. It's climbing a bit over thirty five thousand kilometers after all.
If you don't go that far, you're not at an orbital velocity.
Time for this is around three weeks if you are climbing at 60 KPH. It's around 17 hours if your climber can climb at around 2000 KPH. Wheeled vehicles have been used for most tests. They can make the former speed. Magnetic levitated vehicles can make the latter.
Given the climbing times, most plans have multiple cables called for. There will be up cables and down cables. The cable has to be able to support both itself and the total weight of cargo and transport on it, plus whatever tension is created by the counterweight.
It's an interesting engineering problem.
We don't have a good material yet for making the cable. The best so far is some plastic coated carbon nanotube rope. I haven't seen any yet in lengths longer than a few centimeters. The Japanese are working on it. They claim to be able to make lengths of up to a kilometer. That may be marketing speaking however.
But the lengths needed are more like fifty thousand kilometers per cable however. That's why nobody has tried yet to actually build one. We simply can't do it yet. It's getting closer to possible however.
Kevlar would work fine for the Moon or perhaps Mars. Steel is possible, but the steel cables for the Earth would be literally thousands of kilometers thick at the top. Not really doable.
There are other problems as well. Those include dealing with meteorites, debris collision in orbit, vibration induced by atmospheric winds, power transfer, and flammability issues.All of these seem solvable, but it's not an easy problem.

Maybe if we just launched from high elevations it could be more cost efficient. There are high elevation plateaus in Chile, just a thought.

 

[Catastrophe]

"In pysics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, it is often represented as the product of force and displacement." Wiki

The work is the same although the efficiency of different methods may differ.

Cat )

 

[Particle Article]

the theory is that centrifugal force pulls a counterweight outwards, allowing the outward termination to levitate

 

[josefnspace]

Q. How do you get a spacecraft up a space-elevator?

A. One piece at a time.

Robinson's trilogy Red/Green/Blue Mars
describes space elevator operations in very real terms

 

[Catastrophe]

the theory is that centrifugal force pulls a counterweight outwards, allowing the outward termination to levitate

Does that not have a very high ratio of circular force to upward lift?
I.e., is it not very inefficient?

Cat

 

[Particle Article]

the Earth travels at around 1500 kmh at the equator, so this device would work best on the equator, not either pole as far as I can see.
the line needs to be light and the weight massive as far as I can think. the termination weight needs to be well clear of Earth's gravity
The maths for this could be done by an interested party, I hear that even kevlar line does not possess the needed strength per weight