Questions tagged [space-elevator]

Questions about a hypothetical transportation system between Earth and space that would not require large rockets to transport payloads.

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66
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17answers
20k views

Why is using a space elevator cheaper than rocket power?

Why is rocket power so much less efficient? In both cases you want to lift a given weight a certain height. What does climbing a tether give you that you don't have when using rockets? Wouldn't a ...
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5answers
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If we build a space elevator from Earth surface to GEO, could I step off it at GEO and remain in GEO?

Ignore for a moment the question of whether building such a space elevator is practical. Let's also ignore the minute delta-v involved in "stepping off" something in orbit. If we were to build a ...
32
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3answers
2k views

Could a partial space elevator be practical and useful?

Would it be technologically and economically practical to build and operate a space elevator that only provided transport between lower and higher orbital paths? Such a mechanism would only avoid some ...
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3answers
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What technological barriers do we need to overcome to build a space elevator?

The concept of a space elevator unfortunately still seems like one confined to fiction, at least for now. However, I've heard some sources claim that carbon nanotubes could be the first material ...
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11answers
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Why isn't it possible to build a space elevator at the north pole?

Why isn't it possible to build a space elevator at the north pole? Why does it have to be built on the equator?
23
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1answer
1k views

What's the path of something dropped from a space elevator

What sort of paths would payloads follow after being released from a space elevator such as the one described in Clarke's Fountains of Paradise?
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6answers
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Why can't they just drop a solar winch down from a shuttle and have planes fly up and clip things on?

Why can't they just drop a solar winch down from a shuttle and have planes fly up and clip things on? I know of the idea to have a space lift but the cable necessary is too expensive. Why can't we ...
14
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7answers
5k views

Would reusable rockets render the idea of space elevators useless? [closed]

With the expected advances in reusable rocket technology within the next decade, will constructing a space elevator become meaningless? Or will it still be way cheaper, safer and convenient to use ...
14
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4answers
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What is a “space elevator”?

I've seen an hypothetical "Space elevator" referenced in various media the last couple of years. Is this something thats really planned in the making, or just a hypothetical scenario? How will a space ...
13
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5answers
4k views

Why does the material for space elevators have to be really strong?

If the space elevator platform (The very top) is orbiting a planet in a geosynchronous orbit, wouldn't the forces on the elevator "rope" be minimal?
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5answers
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How long would it take to ride to the top of a space elevator?

The question What is a “space elevator”? describes two key points about the length of a space elevator: equatorial geosynchronous orbit at 22,245 miles (35,800 km) above mean sea level, and an ...
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3answers
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Space Elevator Between Doubly-Tidally Locked Bodies

Space elevators may be a reality only in the future, but I know we have the basic principles down pat. Something has been bugging me, though. If we had the proper materials, we could build such an ...
13
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3answers
918 views

Between a space elevator on Mars versus the Moon, which would have lower material strength requirement?

On one hand, the Moon has lower gravity, and the gravity from Earth also reduces the distance the it has to span. This is particularly true for EML-1, and a little less so for EML-2. I don't know if ...
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2answers
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Where could we build a space elevator today (2014)?

A space elevator is an interesting concept, allowing for very low cost transit to orbit. Currently we don't seem to have a technology that will provide a strong enough cable to make the climb from ...
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4answers
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Reverse Lunar Space Elevator

The possibility of a space elevator from the lunar surface is discussed in this question. A lunar elevator for the purpose of return to Earth could be achieved at the L1 Lagrange Point between Earth ...
11
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4answers
671 views

What tensile strength would be needed for a lunar space elevator?

A space elevator from the Moon's equator, slightly past the L1 Lagrange point and extending into cis-lunar space would have a substantially lower tensile strength requirement than an Earth-based ...
11
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1answer
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Tethered geostationary orbit

One of the biggest issues that I've heard of in building a space elevator is the high tensile strength of the cord used to tether the the elevator to the ground. If there's a structure that's at ...
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5answers
1k views

Would a 'space elevator'/sling on a rotating asteroid work?

It is possible to find numerous studies of space elevators, for Earth, Luna, Mars and even Phobos. But would a 'space elevator' work on an asteroid? I use scare quotes because typically the point of a ...
11
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2answers
441 views

Is it feasible to pump fuel into orbit?

Imagine a huge fuel depot in geostationary orbit. Suppose further that it is tethered to the Earth and that there's a large hose snaking down all the way. Is it feasible to pump fuel up 35,786km? Can ...
11
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2answers
853 views

Benefit of sling shot effect with a space elevator

The upper end of a space elevator is moving considerably faster than orbital speed at that distance from Earth. As a result anything released from the top of elevator would get thrown away from the ...
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4answers
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Could I tie together two satellites at different altitudes?

Could I tie together two satellites at different altitudes? Is there an existing name for this? Can this be stable, or will it spin out of control? How strong of a rope will I need? For the sake ...
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2answers
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Can we make a space blimp?

OK. Hear me out. I know that blimps float because of the buoyancy of air, and there is no air in space. But think of the way a boat floats on the top of water even though the material that the boat is ...
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2answers
718 views

Impact of space junk on Earth based space elevators

It is well known there is a lot a space junk orbiting the Earth. From previous questions posted on this site it appears that if it were possible to establish a space elevator cable for Earth it would ...
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1answer
402 views

Needed height from the release of a space elevator to get a stable elliptical orbit?

As we know, something released from around 36000 km height from a space elevator will remain in geostationary orbit around the Earth. Things released from lower will go into an elliptical orbit ...
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2answers
913 views

Can a “free launch” from a space elevator really be free?

The question Benefit of sling shot effect with a space elevator implies that you can get free $\Delta V$ from a space elevator launch. As highlighted in this answer on SciFi quoting Sheffield book "...
6
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2answers
308 views

Atmospheric effects on a space elevator

Were I able to build a space elevator (ignoring for the moment that I can't due to current material science etc), what issues would there be relating to atmospheric conditions? Presumably it would be ...
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2answers
867 views

How would the foundation/anchor for a space elevator work?

In a perfect scenario the space elevator is in Geosynchronous Orbit, it could be suspended a papers width above an egg, the egg would never be harmed and there would always be just enough room to ...
6
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1answer
389 views

“Propeller-head” polar space elevator?

"Why isn't it possible to build a space elevator at the north pole?" made me think... Like the funny hat with a propeller on a kid's head - replace the head with Earth and propeller blades with space ...
6
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1answer
516 views

Space Elevator Hurdle: Can you ground out the Van Allen belts?

Problem One of the biggest problems of a space elevator concept is that the elevator would have to be centered on the equator, and its tethers would pass through the Van Allen belts that contain super ...
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1answer
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Space elevator - cord thickness - why is the strength to weight ratio a problem?

To my understanding the main problem with space elevators is that the strength to weight ratio is not high enough to support the cable's weight. Naturally the first thought that would come to mind is ...
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2answers
925 views

Standing at the top of a space elevator would 'up' be towards the Earth?

If I rode a space elevator to the top, assuming only natural forces apply, would the Earth be over my head or under my feet? If it was over my head how is that possible?
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1answer
425 views

How will the angular momentum of a Space Elevator be preserved?

This question has been bugging me for some time. First a little background. We know that a space elevator is essentially a (very) long rope with a heavy asteroid attached at the other end well beyond ...
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1answer
229 views

Rotovators and booster recovery: is there a free lunch here?

Rotovators have the big advantage that they don't have as much force on them as a full space elevator and thus can be constructed without such incredibly strong materials. The big downside is that ...
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1answer
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What sensations would I feel on a Space Elevator?

For simplicity: Standard, 50,000km space elevator from equator to the counterweight. Acceleration, followed by constant velocity, followed by deceleration, and a stop past geostationary orbit. What ...
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2answers
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Why would a space elevator / structure need to be in Geosynchronous orbit?

I've read a bunch on space elevators and from what everyone is saying, it would be required that the elevator is in geosynchronous orbit. From my understanding, that is so that it would stay fixed in ...
4
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2answers
236 views

Could a skyhook be used to remove space junk?

Is it possible to remove the space junk having orbital velocity with the help of a skyhook? Has any country in the world planned to place a skyhook in orbit?
4
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1answer
612 views

Taper ratio for partial space elevator

The calculations for the taper ratio of a space elevator don't seem to be all that difficult and it is easy to find some equations to use. You can even find an expression written out for the total ...
4
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1answer
385 views

Would it be possible to suspend a space elevator in the stratosphere?

Having a material strong enough to support a space elevator built from the ground up seems like it may never be able to happen. I had also seen another suggestion for building a space elevator ...
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0answers
145 views

What is the specific compression strength of an orbital tower structure?

Taper ratio is a central concept for space elevators and tethers. It tells how much larger the cross section of the tether has to be at one end of the tether, compared to the other. Being a ...
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3answers
1k views

How about space ziplines

I've heard of the hypothetical space elevator. But how about space ziplines. Have the idea been explored if so what are the challenges? By zipline I mean giant long cables connecting space station to ...
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4answers
411 views

If a space elevator uses both compression and tension design, will we still need new materials?

We build as much of the space elevator under compression as possible and the remaining part using carbon based materials. Is this trick going to work or am I missing something?
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3answers
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How does the gravity of Earth change as you climb a space elevator?

I'm doing research for a movie. If you were in a space elevator/tower at an altitude of 250 miles, how much gravity would you experience? (I've heard various estimates of .9Gz and .65Gz) How about if ...
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2answers
201 views

Can the modern space elevator design be altered so as to reduce the tensile strength requirement of the material?

Most probably, we'll be able to mass manufacture diamond nano-threads and carbon nano-tubes in the near future, but they might not be strong enough. Is there a way to significantly reduce the tensile ...
3
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0answers
394 views

Chinese find material to make space elevator. How much will the cable weigh?

The article China has strongest fibre that can haul 160 elephants – and a space elevator? came out today in the SCMP, and I would like to find out how much the cable would weigh. But I'm not sure if ...
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1answer
257 views

“Free energy” moving the space elevator possible?

In this other question I have found the following: A space elevator can climb at a low, constant vertical speed (albeit for a very long climb), and gets its orbital speed for free [borrowed from ...
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2answers
262 views

What is the shape of a space elevator?

When we think of a space elevator, we might usually think of a purely vertical tower, sticking perpendicular to the surface of the Earth, extending way past the geostationary belt, to the end-mass. ...
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3answers
404 views

Space elevator: Is there some way you could make one to a low earth orbit?

All the current proposals for a space elevator seem to be for one to the GSO.However is there some proposal for a space elevator to a low earth orbit? I know that it would require continuous power to ...
2
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3answers
558 views

Could pull from a space elevator be used to assist a rocket launch?

Well, more specifically, using a counterweight like you'd find in a non-space elevator to give the rocket a little acceleration before firing up and spending all that fuel-to-lift-the-fuel-to-lift-the-...
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1answer
102 views

How do you find ZRVTOs between tethers from coplanar, tidelocked bodies?

In 1984 JPL engineer Paul Penzo described a ZRVTO (Zero Relative Velocity Transfer Orbit) between an elevator anchored on Deimos and an elevator anchored on Phobos. Here is a Penzo’s illustration: ...
2
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1answer
151 views

Which solar system objects could a space elevator be built on with modern tech?

Which solar system objects have the right combination of low gravity and fast spinning rate, that an object tall enough to be a space elevator could be built on with modern construction tech? By "...