SpaceElevator: Why is Cable Thicker at the Center?

• doublemint
In summary, the conversation discusses the design of a space elevator and the forces acting on the cable. It is stated that the center of the cable must be thicker than the tips due to the forces pulling from the platform and station. The participants also mention that there may be stress on the cable and that the center experiences the biggest load. The conversation ends with gratitude for the help provided.

doublemint

Hi all, I am doing a paper on the space elevator. On the wikipedia site it states that a climber would be far better off on a stationary cable rather than having a cable pulling the climber since "the cable to be significantly wider at the center than the tips". Why does the center have to be thicker then at the tips??

Thanks

DoubleMint

What are the forces on the cable at the bottom/middle and top?
Hint - do you need to attach the top to anything?

Well at the bottom of the cable, there is the platform and on top is the station. So there are forces pulling from those two points. Therefore the cable must be thicker in the middle to withstand the forces??

There are no forces at the ends

Well there must be some sort of stress on the cable...

doublemint said:
Well there must be some sort of stress on the cable...
Yes. At the centre. The rest of the cable is hanging down in both directions from the centre.

Ignore one half of the cable for the moment and think of just one cable hanging down from a very tall ceiling. What part of that cable experiences the biggest load?

Thanks for both of your help!

1. Why is the cable thicker at the center of a space elevator?

The cable of a space elevator is thicker at the center to support the weight of the entire structure and the payload that it carries. As the elevator extends farther from the Earth's surface, the weight it needs to support increases. Therefore, the cable needs to be thicker at the center to provide enough strength and stability.

2. How thick is the cable at the center of a space elevator?

The exact thickness of the cable at the center of a space elevator depends on the specific design and materials used. However, it is estimated that the cable needs to be at least 5-6 feet in diameter to support the weight and stress of the elevator and its payload.

3. What materials are used to make the cable of a space elevator?

Currently, there is no material strong enough to make a cable that can reach from Earth's surface into space. However, proposed materials for space elevator cables include carbon nanotubes, graphene, and other advanced materials with high tensile strength and low weight.

4. How does the cable of a space elevator stay in place?

The cable of a space elevator is anchored to a space station or counterweight in geostationary orbit, 22,236 miles above the Earth's surface. This geostationary orbit means that the space station is always in the same position relative to the Earth, providing a stable anchor for the cable to stay in place.

5. Can the cable of a space elevator break or snap?

In theory, the cable of a space elevator could break or snap due to extreme weather events or other unforeseen circumstances. However, engineers design space elevators with multiple safety features, such as redundancies and emergency brakes, to prevent catastrophic failures. Additionally, regular maintenance and inspections would be necessary to ensure the safety and integrity of the cable.