My Wild Elevator-to-the-Moon Proposal

[Argus Skyhawk]

You know those nifty space-elevators you've heard of? Imagine a dozen or so of those things evenly spaced around the Earth's equator. I know that would be tricky since so much of the equator crosses the ocean, but nothing else about this proposal is going to be easy either, so just accept it.

Now imagine a giant ring connecting all of these elevators at the height of geostationary orbiting satellites (35,786 km). Another elevator connects to this ring, but instead of going down to the Earth it starts at the ring and extends outward. The connection with the outward-bound elevator moves along the ring from east to west so that to an outside observer it remains relatively stationary while the Earth rotates under it once every 24 hours.

The other end of this secondary elevator is rooted in surface of the nearside of the moon. The elevator is flexible, to account for the fact that the moon does not orbit in the exact same plane as the earth's equator. It can also collapse in on itself like a spyglass so that it can shorten to 350,000 km or lengthen to 410,000 km to account for the fact that the moon is closer to the earth at perigee than at apogee.

Imagine climbing into a comfortable compartment on the earth's surface, which automatically rides up to the ring, moves onto the ring, slowly accelerating from east to west until travelling approximately 11000 kilometers per hour, rendezvousing with the second connection, and spending the next day or so travelling in fun zero-G to your vacation destination: Hotel Luna.

Here is my obviously not-to-scale diagram:

I know it's crazy, but is it any more so than a Dyson sphere?

 

[JB2005]

The line is wavy...that's my first problem.

It's certainly imaginative, but with the material that would be required, you could build an armada of spaceships that would be able to get people to and from the moon just as effectively...

Out of curiosity, where would you get the material to build it? Asteroid Belt and Oort Cloud? Or dismantle Pluto? (I speak in seriousness, because we'd need to disassemble stellar bodies in order to get enough material to do this)

Though as I have said, easier to build spaceships.

 

[Robert Maxwell]

Dyson spheres aren't "crazy," just very impractical.

I don't see why the elevators on Earth need to be connected to the Lunar one at all. Wouldn't it make more sense to just have independent elevators/catch poles on the Lunar side of it? It would be possible to time your Earthly launch so that you are caught appropriately on the Moon side. However, you'd probably need separate catch/release elevators on both sides, depending on how you want to deal with deceleration. You could make the receiving side a highly frictive surface to facilitate deceleration, though that would generate a lot of heat. Retro-rockets, if they could be implemented economically, are another option.

I just think the ring concept is a bit too cumbersome.

 

[JB2005]

Question: Would a planetary ring be a good way to cope with over population?

 

[Robert Maxwell]

Question: Would a planetary ring be a good way to cope with over population?

Taller skyscrapers or even artificial islands would probably be more cost effective than hefting the materials for an orbital ring. I mean, it costs billions to keep a handful of humans in orbit right now (the ISS).

 

[JB2005]

Yeah, you're right. Well I thought I may as well ask the question!

 

[Argus Skyhawk]

The line is wavy...that's my first problem.

It's certainly imaginative, but with the material that would be required, you could build an armada of spaceships that would be able to get people to and from the moon just as effectively...

Out of curiosity, where would you get the material to build it? Asteroid Belt and Oort Cloud? Or dismantle Pluto? (I speak in seriousness, because we'd need to disassemble stellar bodies in order to get enough material to do this)

Though as I have said, easier to build spaceships.

I made the Earth-to-moon line wavy to indicate that the connection is flexible, as it would have to be to account for the fact that the moon doesn't orbit in the same plane as the equator.

Once built, traveling to the moon would only require a fraction of the fuel that an armada of spaceships would need.

I'm not convinced you would need all that much material to build it; the connection would obviously be long, but would not have to be very wide. There are currently 3.9 million miles of roads in the US and no one had to dismantle Pluto to build them. Of course, this elevator would probably have to be made of carbon nanotubes, not asphalt, so that is one of many difficulties to keep in mind.

 

[Robert Maxwell]

The line is wavy...that's my first problem.

It's certainly imaginative, but with the material that would be required, you could build an armada of spaceships that would be able to get people to and from the moon just as effectively...

Out of curiosity, where would you get the material to build it? Asteroid Belt and Oort Cloud? Or dismantle Pluto? (I speak in seriousness, because we'd need to disassemble stellar bodies in order to get enough material to do this)

Though as I have said, easier to build spaceships.

I made the Earth-to-moon line wavy indicate that the connection is flexible, as it would have to be to account for the fact that the moon doesn't orbit in the same plane as the equator.

Once built, travelling to the moon would only require a fraction of the fuel that an armada of spaceships would need.

I'm not convinced you would need all that much material to build it; the connection would obviously be long, but not would not have to be very wide. There are currently 3.9 million miles of roads in the US and no one had to dismantle Pluto to build them. Of course, this elevator would probably have to be made of carbon nanotubes, not asphalt, so that is one of many difficulties to keep in mind.

You are talking about carbon nanotubes tens of thousands of miles long, put under enormous stress. Yeah, there are definitely some hurdles there.

 

[RobertVA]

In addition to the other concerns above:

With the ring spinning one revolution every 24 hrs and the base of the lunar cable going around only once every 29 days it's going to be quite a velocity change attaching to the bottom of the lunar cable.

 

[Alpha_Geek]

Does the ring spin at an incredible velocity?

 

[Argus Skyhawk]

With the ring spinning one revolution every 24 hrs and the base of the lunar cable going around only once every 29 days it's going to be quite a velocity change attaching to the bottom of the lunar cable.

Upon reassessing the proposal, that is my own biggest concern. If I have done my math properly, the connection between the ring and the lunar cable would have to be traveling along the ring at about 11000 km/hour, which would be faster than supersonic jets. I don't have a good solution for that one. Or even a bad one.

 

[Argus Skyhawk]

Does the ring spin at an incredible velocity?

My idea was that the ring would be geostationary.

 

[Alpha_Geek]

What makes it stay with the earth?

 

[Trekker4747]

I rate this thread 3 Tachys.

 

[Alpha_Geek]

The Ringworld is unstable!

 

[RobertVA]

Does the ring spin at an incredible velocity?

My idea was that the ring would be geostationary.

Geostationary isn't any more stationary than you are. The Earth rotates once very twenty four hours (relative to the Sun - a little slower relative to the rest of the universe). Orbiting objects, like satellites and the top end of hypothetical space elevators, are moving horizontally at such a high velocity they perpetually miss the Earth. The only thing special about "geostationary" is that a paired altitude and velocity is selected that is synchronous to a point on the planet's equator. The geosycronious satelite has to be traveling at a high velocity to cover the circumfrence of such a large circle in only 24 hours.

And that isn't taking the planet's orbital velocity around the sun and the solar system's velocity around the center of the galaxy into account. Earth spinning, wobbling because of the moons gravity, orbiting the sun, sun orbiting the galaxy (some scientists think there's a supermassive black hole at the center). I'm going to stop thinking about it for a while so I don't get motion sickness! (kidding)

 

[Argus Skyhawk]

What makes it stay with the earth?

It is in geosynchronous orbit around the earth.

Geostationary isn't any more stationary than you are. The Earth rotates once very twenty four hours (relative to the Sun - a little slower relative to the rest of the universe). Orbiting objects, like satellites and the top end of hypothetical space elevators, are moving horizontally at such a high velocity they perpetually miss the Earth. The only thing special about "geostationary" is that a paired altitude and velocity is selected that is synchronous to a point on the planet's equator. The geosycronious satelite has to be traveling at a high velocity to cover the circumfrence of such a large circle in only 24 hours.

And that isn't taking the planet's orbital velocity around the sun and the solar system's velocity around the center of the galaxy into account. Earth spinning, wobbling because of the moons gravity, orbiting the sun, sun orbiting the galaxy (some scientists think there's a supermassive black hole at the center). I'm going to stop thinking about it for a while so I don't get motion sickness! (kidding)

Did you think I wasn't aware of all that?

 

[Argus Skyhawk]

I rate this thread 3 Tachys.

Well, in the original post I did say "I know it's crazy..."

 

[Alpha_Geek]

What RobertVA said. Look up some of the math done on Ringworld and you'll see some of the difficulties this type of structure would face.

If this were to be locked to geosynch, the people already holding communitcation and satellites would be pretty torqued off since they'd have to move. There's only 1 Clark Belt.

And yeah, it is a... loopy... idea, but at least you put some math into it. The speed for Geosynch is 11068kph. You got that goin' for ya.

But if you want loopy, just build a conveyor belt for the whole round trip and be done with it. LOL

 

[paudemge]

I think most of the energy for space craft are the launching, so just elevators to get a craft up and away from earth would probably be sufficient. It could then fly the rest of the way to the moon. Maybe a smaller elevator on the moon itself for the return trip