Some scientists have an idea to bui 1

[Abd K]

Some scientists have an idea to build an elevator that could pull the spaceship from the ground of the earth to the spaceship orbiting around the earth. However, during the mission, the sling that is used to pull the spaceship from the ground to the spaceship orbiting around the earth is broken. The NASA engineer suggests that we increase the diameter of the sling, which may take more loads. What do you think about this idea? Is it the right thing to do? Can you verify mathematically? If this idea is not good, can you suggest the alternative? Please state all necessary assumptions.

 

[MintJulep]

Assumption: The sling material and application are such that Stress = Force/Area is valid.

Conclusion: Increasing the sling diameter is the right thing to do.

Does that help?

 

[ThomasH]

You mention "Some scientists", do you have a reference for this idea?

 

[zeusfaber]

The idea goes back at least as far as Tsiolkovsky in the 19th Century. I've never seen a satisfactory explanation of how the cable is supposed to be laid in the first place (there's a significant coriolis force to deal with).

 

[Compositepro]

For any given tensile strength and density of a material there is a maximum length of cable/rod that can be self-supported without breaking. Making it a larger diameter will not help in making it longer.

 

[Geoff13]

A space elevator was the basis of a novel by Arthur C Clarke (Wikipedia) in 1979.

He had the advantage of been able to use "continuous pseudo-one-dimensional diamond crystal" for the cable without the difficulty of actually creating said material.

 

[LittleInch]

The tallest man made structure in the world is less than 1km high.

The ISS orbits at about 400km above earth.

"Space" is deemed to start at about 80 to 100km above earth.

So this is pure fantasy.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[GregLocock]

While I don't think the sling idea is a space elevator as such it has been proposed as away of getting stuff off low g bodies.

The space elevator will wipe out every unmaneuverable satellite in LEO in about 6 years, I vaguely remember.

Cheers

Greg Locock


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[rb1957]

Apologies, as I think you are not a native english speaker, but your post is "word salad".

first sentence ... "Some scientists have an idea to build an elevator that could pull the spaceship from the ground of the earth to the spaceship orbiting around the earth." This is quite clearly talking about the space elevator concept, where a cable is erected to carry "stuff" up the geo-stationary orbit, and to balance the cable a counter weight is added above geo-stationary orbit so that the weight of the whole is balanced by the centrifugal force of the counterweight. And yes, this is a concept but some research is going on the see if we can make it a reality. Google "space elevator".

Then 2nd sentence "However, during the mission, the sling that is used to pull the spaceship from the ground to the spaceship orbiting around the earth is broken." Sling? where did this come from ? if it lifts the vehicle, what does it pull against ? I think this is not the right word, and so confusing the replies. The current idea is for the lift vehicle to be powered, rather than lifted, possibly by solar cells with the energy beamed to the lift vehicle by ultrawaves.

Because you then go back to the space elevator concept, the key problem is the strength to weight ratio of current materials. We need more material to react the load, but this extra material causes extra load, etc. Yes, this is the key design problem with space elevators. Currently the best material we have are carbon nano-tubes. Such a space elevator is, in my mind, built starting at geo-stationary orbit and building in both directions, keeping the structure balanced.

Building a space elevator on Earth is a very daunting, difficult, task. I suspect we are more likely to see one on the Moon or even Mars before we see one on Earth

"Wir hoffen, dass dieses Mal alles gut gehen wird!"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[MintJulep]

I took "sling" to be not the main cable.

If the main cable, then the problem of self-weight increasing the load exists.

 

[waross]

Try designing a tapered cable.
As the force on the cable increases, increase the diameter.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[LittleInch]

Sounds to me like a question which has been raised by a tutor and the OP is looking for other people to do his or her homework.

The "please state all necessary assumptions" gives it away a bit ...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[rb1957]

well, this is a student forum ... but, yes, we don't do their homework for them. Just a few breadcrumbs.

"Wir hoffen, dass dieses Mal alles gut gehen wird!"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[BEMPE16524]

OP, you copied exactly your lecturer's question and paste it here?



R.Efendy

 

[rb1957]

haven't been here long, eh ? pretty typical, and oft ranted at ...

"Wir hoffen, dass dieses Mal alles gut gehen wird!"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[BEMPE16524]

perhaps...

R.Efendy

 

[waross]

I don't usually do homework but this time"The Devil made me do it".
Challenges such as this may often be overcome by the liberal use of unobtainium.
Based on the use of unobtanium, with a strength to specific weight ratio to support 10 miles of its own weight including internal elevating functions..
A cylinder of unobtanium 5 miles in height has enough reserve strength to be able to support 5 miles of a cylinder of similar construction.
So
Two 5 mile high cylinders in parallel will support 10 miles of similar structure.
Now you are up to 15 miles.
For the next 5 miles use 4 cylinders in parallel.
For the next 5 miles use 8 cylinders in parallel.
Caveats:
At suitable intervals calculate and in your calculations the reduction in gravitational forces.
This design is contingent on the design and construction of suitable false-work to support the structure during erection.
Was that so hard?
Have you considered switching majors?

 

[ChorasDen]

Waross, if we are going the magical material route, why not also just drill a hole through the earth from the other side of the sling, then we can accelerate the payload through the earth and back out the other side, reducing the unobtainium material cost and requirements?

 

[Maslov]

I agree with Choras. Have you seen the cost of unobtainium these days? Not to mention it's a nightmare to work with.

 

[waross]

I guess if you find an unnamed magical material to shore the shaft at the earth's core it may work.
You have to overlook that the energy gained during the dive to the center will be used climbing back out of the gravity well to the earth's surface.
However if you start releasing water out the back of your transport device as you enter the higher temperature regions of the depths, you may be able to achieve escape velocity.
A great elevator going up.
Less than great coming down. grin