Elevator to space?

[Arlo1]

On FB I joined a page called reality pod necause it seems like some cool stuff gets shown, and here is the new feed on the spce elevator.

http://realitypod.com/2013/02/japanese-company-to-build-an-elevator-from-earth-to-space/

A Japanese company is now prepping to build the elevator to space and will be completed by 2050. Japan’s Obayashi Corporation thinks that NASA is not moving fast enough so they plan to take the responsibility of do the next big thing in space research. However, the feasibility of the plan and the current technological capabilities of the company are still not disclosed. The total length of the elevator will be 22000 miles and will connect earth to a space station. The ground station on earth and the space station will be connected together through a cable. The space station will also act like an orbital counterweight to hold the cable up.

 

[parajared]

Sounds implausible to me due to the logistics behind keeping the thing from toppling over and the sheer amount of materials used.

 

[Arlo1]

Sounds implausible to me due to the logistics behind keeping the thing from toppling over and the sheer amount of materials used.

I admit I have not read it thoroughly yet. But I think the counter weight in space will be in orbit pulling the whole thing outward... Kinda like a weight on a string in your hand as you spin it will pull away from you. I think the whole thing is ridiculous and man the 8 day elevator ride will be scary as shit thinking for 8 days what could go wrong.... Maybe if the provide parachutes and oxygen masks with pressurized suits

 

[Drunkskunk]

Interesting. But 2 technical problems will stop this from happening in 37 years.

The first issue seems minor, but logisticaly it will be a nightmare. Anything in orbit around the earth is going to pass through every single point along the equator. A satellite, or piece of space junk, or micro meteorite will spend as much time above the equator as it does below, crossing back and forth every orbit. That can't be avoided, its just how the physics work.

Unfortunatly, that means every single satellite, along with every old nut, bolt, lost wrench, and natural spase debris will slam into the cable at 17,000 miles an hour, eventualy. At that speed 1 gram of debris is going to do huge damage. No material known today would survive that impact unscathed. You could no longer have satellites in orbit. So you would need to sweep earth's orbit clean, and give up all Satnav, satellite comunications, satelight weather forcasting, satelite sscientific study, ect. The only way to avoid that is to build many SEs so the stations on the end could cover horizon to horizon.

And that brings us to the second problem. There is no known material that could withstand the forces that a cable 22,000 miles long would be under. The cable will need to be able to take the weight of the platform, plus it's own weight. While the center will be in zero G, the ends won't be, and the cable will have to support all 22,000 miles of what ever it's made of. That could be trillions of tons.

This could happen eventualy, and indeed it should happen. But I don't see us getting it done in 37 years. there are so many minor technical issues beyond the first two that we may spend generations just developing the technology needed to even begin serious research for this.

 

[Chalo]

The length of a geostationary tether would need to be about 60,000 miles, because 22,000 miles out is only the center of gravity of the system. Since the earth's gravity diminishes with distance, the piece of tether outside geostationary orbit would have to be much longer than that between the station and the surface.

On the plus side, a tether cutting through that much of the earth's magnetic field can harvest enough electrical power to run the elevators and remain on station.

Another format for a space elevator is a wheel-type tether, with a massive satellite at a lower orbit extending two or more tethers that rotate, essentially "rolling" on the atmosphere of the earth and achieving zero or near-zero relative velocity at their lowest points. Payloads would be connected to the tether at the low point, then transferred to a much higher, faster orbit on the upper side. Or they could be released at escape velocity, or simply carried up to the central mass.

Both these designs presume materials properties that don't exist in commercially produced materials yet. One promising technology that could potentially unlock these projects is carbon nanotube fiber. But even if we had the materials available, the scale of an engineering project like this is unprecedented.

 

[MikeFairbanks]

I thought the priority was in developing planes that could switch fuels in order to continue their accent into the upper atmosphere and break away from the earth's gravity (in so much as to go into orbit or travel beyond our moon,etc.).


I taught my students just yesterday that we have the technology now to go anywhere in the world in an hour, but that the concepts of time travel and teleportation are likely impossible for a variety of reasons. First, you can't send matter at the speed of light, only information. So your body would have to be deconstructed in one spot, analyzed during the process, and then the info sent at the speed of light to another location where various tanks of chemicals would be used to reconstruct you. Sounds impossible to me. Plus, if it were possible then someone could send you to several places at once and you might be reconstructed in Denver, Miami, Moscow and Bakersfield all at the same time. Cloning.

The same goes for time travel, except you have the added problem that going back in time is not only impossible, but if you could go back in time just ten minutes you would find yourself in space because the Earth is not holding still. It spins, of course, and also is traveling at 67,000mph in an orbit around the sun, which means that we travel a distance of 18 miles in one second, or the diameter of the earth in about seven minutes. Traveling, therefore, just ten minutes into the past would put you outside the entire planet and you would be dead.

The earth has never been in one place. It will never visit the same place twice because the sun is also moving through space as it orbits the center of the galaxy.

And the galaxy is moving too.

For these reasons I don't think time travel and teleportation are possible ever.


Wow, I digress. As far as a space elevator is concerned: It sound hokey to me. I'd rather a jet that can travel all the way from the runway to orbit.

I mentioned before that I taught my students that we can go anywhere in the world in under an hour via the Space Shuttle (yes, it's out of commission and all that, but you get the idea). Obviously it's too expensive to just launch a space shuttle with seven people, get into orbit and then drop right back down in Japan less than an hour later. But it's possible.

That, to me, should be our priority: Finding the least expensive way possible to break out, go into orbit, and drop back in on the other side. Imagine if one day your boss in Los Angeles tells you to be in Moscow by lunchtime. It's 9am. You head to the airport and buy a quick ticket, take off at 10:30am, leave the atmosphere twenty minutes later. Stay buckled in (or not), and another half hour later you're on your way back down. Now that would be cool.

 

[HAROX]

Mike, i must remind you willie wonka already got that transporter thing perfected, and as for time travel, my boss already has that licked. He always says, 'I want that done...yesterday'

 

[Dauntless]

http://www.amazon.com/Black-Holes-Time-Warps-Commonwealth/dp/0393312763/ref=sr_1_1?ie=UTF8&qid=1361048820&sr=8-1&keywords=kip+thorne

 

[salty9]

I don't know for sure but I suspect from Newton's Third Law that the energy to power such a space elevator would come from the Earth's rotation eventually slowing it to a point where it becomes unstable with unforeseen results. If we do develop a way to build this I hope we don't until we become wise enough to know whether or not we should. The law of unintended consequences bites as bad or worse than Murphey's Law.

 

[Chalo]

I don't know for sure but I suspect from Newton's Third Law that the energy to power such a space elevator would come from the Earth's rotation eventually slowing it to a point where it becomes unstable with unforeseen results.

I hate to break it to you, but the earth's rotation has been slowing all along. What do you reckon powers the tides?

And as for Mike Fairbanks's preference for a space plane: The problem with space launch is and has always been the amount of energy required. An orbital vehicle that requires fuel will never be economical. A space tether/elevator would be a much less energy-intensive way to reach orbit.

 

[salty9]

I do know that like King Canute we can not stop the tides but we do not have to accelerate our journey to chaos.

 

[doctorGONZO]

There are many serious problems in the orbit elevator concept. Here is one that hasn't been mentioned (or maybe I missed it).

The elevator "cable" itself will act as a power tether. It will produce a continuous back-torque to slow the cable, whether or not power is drawn from it. It is very simple basic electrodynamics. So the elevator assembly orbital velocity will continually deteriorate from the first moment of service. Not surprisingly, it will need as much power input to maintain orbit as the cable-tether could produce, except there will be resistance loses, so that some net power input will always have to be input to hold the orbit.

And another one...the elevator will require exactly as much energy to move each pound up to orbit as a space plane would use. Here it is very simple basic mechanical physics. It requires a specific amount of energy to lift the weight against gravity and give it horizontal velocity regardless of the means used to lift it and shove it.

Sorry, no free lunch and no magic elevators. Apologies to Mr. Clarke. I enjoyed the movie.

 

[salty9]

Or, perhaps we could run an electric catapult up the west slope of the Andes and launch satellites electrically.

http://www.defenseindustrydaily.com/emals-electro-magnetic-launch-for-carriers-05220/

Near the equator we should get maximal rotational assist and avoid chemically blasting through the heavy lower atmosphere.

 

[Chalo]

And another one...the elevator will require exactly as much energy to move each pound up to orbit as a space plane would use. Here it is very simple basic mechanical physics.

You account only for the kinetic energy required to attain altitude and orbital velocity. Rockets require quite a bit more than that, both to oppose aerodynamic drag and to counter gravity drag. And that's compounded by the fact that jet propulsion by whatever means is quite a bit less efficient than mechanical or electromagnetic traction. And compounded again by the fact that you have to use so much energy to accelerate the fuel itself, which can be up to about 90% of the launch vehicle's initial weight. If you don't have to accelerate the rocket fuel, that's about a five-fold advantage all by itself.

I worked for years for an company that looked at lots of different prospective launch techniques, and rocket propulsion is about the most energy intensive of any of them on a joules per kg to orbit basis. We only use it because it is technically understood, with relatively low initial costs.

 

[JennyB]

If I remember my A level Physics aright, the fastest no-power Earth orbit would take about 86 minutes. The trouble with point-to-point orbital passenger flight is with any bearable acceleration it would take rather longer than that to get up to speed. :?

 

[Toorbough ULL-Zeveigh]

the project is too big to swallow in one gulp.
they need to take baby steps before they get there by building an escalator to nowhere first.

 

[salty9]

the project is too big to swallow in one gulp.
they need to take baby steps before they get there by building an escalator to nowhere first.

Should be able to sell it to Congress by telling each Represenative that there will be a stop in his district.

 

[John in CR]

I'll take an anti-gravity device over a space elevator.

 

[Hillhater]

I'll take an anti-gravity device over a space elevator.

Im sure you can smoke something to get that effect !! :wink: :lol:

 

[doctorGONZO]

And another one...the elevator will require exactly as much energy to move each pound up to orbit as a space plane would use. Here it is very simple basic mechanical physics.

You account only for the kinetic energy required to attain altitude and orbital velocity. Rockets require quite a bit more than that, both to oppose aerodynamic drag and to counter gravity drag. And that's compounded by the fact that jet propulsion by whatever means is quite a bit less efficient than mechanical or electromagnetic traction. And compounded again by the fact that you have to use so much energy to accelerate the fuel itself, which can be up to about 90% of the launch vehicle's initial weight. If you don't have to accelerate the rocket fuel, that's about a five-fold advantage all by itself.

I worked for years for an company that looked at lots of different prospective launch techniques, and rocket propulsion is about the most energy intensive of any of them on a joules per kg to orbit basis. We only use it because it is technically understood, with relatively low initial costs.

Thank you for your completely kind and generous reminder of Gravity Drag. It was not needed, since I have been aware of that factor for many decades. I am sure that you meant only to be helpful and kind to a person assumed to be much more ignorant than yourself, and you are thanked accordingly. You have implied that Gravity Drag will be absent in your Orbit Elevator; I will be delighted to read your detailed description of how you plan to eliminate it.

You are invited to read my post again carefully. It was composed carefully to focus on moving payload to orbit. I am aware that much of the fuel energy in a rocket is thrown away in lifting the fuel itself.

When you carefully consider how you will provide power to your elevator, you will discover a problem. You will discover that it will be inefficient. You will discover that when you try to run electric power through 22,000 miles of "cable" you will lose a bit of it by resistance. Across 22,000 miles will you lose 5-fold of the power required to move your payload, or even more than that?

(helpful hint): You will have a truly enormous amount of resistance across 22,000 miles.

 

[Chalo]

Thank you for your completely kind and generous reminder of Gravity Drag. It was not needed, since I have been aware of that factor for many decades. I am sure that you meant only to be helpful and kind to a person assumed to be much more ignorant than yourself, and you are thanked accordingly. You have implied that Gravity Drag will be absent in your Orbit Elevator; I will be delighted to read your detailed description of how you plan to eliminate it.

I'll answer your question with another question:

How much energy does it take to hang a kg of mass motionless on a cable, versus how much energy to hang the same kg of mass motionless using a rocket? That's gravity drag, and it's why those losses would not be incurred using a system of mechanical traction. A rocket leaving Earth's surface has to come up with 9.8m/s^2 of acceleration and only the margin above that is available for upward movement, where a traction system must only come up with the energy required to move.

At the moment of launch, Saturn V was 85% propellant by mass, with 6.5 million pounds of total vehicle weight (thus over 5.5 million pounds of propellant) and only 7.6 million pounds of thrust. So it could accelerate at one-sixth of a G at first, making it less than 15% efficient at the outset due to gravity drag, while 85% of what it lifted off the pad was fuel to be burned later. A rocket engine has a maximum raw efficiency of about 70% in converting fuel energy to thrust. Thus, the Saturn V's initial efficiency at lifting dry mass during the period of highest energy consumption was about 15% of about 15% of no more than 70%, or roughly 1.5%. And that does not distinguish between payload mass, the dry mass required to support the payload, and the dry mass required to support all the propellant.

To put it in automotive efficiency terms, Saturn V's first stage made 5 inches per gallon of kerosene and liquid oxygen during its entire flight profile, low and high efficiency extremes included.

 

[doctorGONZO]

Thank you for your completely kind and generous reminder of Gravity Drag. It was not needed, since I have been aware of that factor for many decades. I am sure that you meant only to be helpful and kind to a person assumed to be much more ignorant than yourself, and you are thanked accordingly. You have implied that Gravity Drag will be absent in your Orbit Elevator; I will be delighted to read your detailed description of how you plan to eliminate it.

I'll answer your question with another question:

How much energy does it take to hang a kg of mass motionless on a cable, versus how much energy to hang the same kg of mass motionless using a rocket? That's gravity drag, and it's why those losses would not be incurred using a system of mechanical traction. A rocket leaving Earth's surface has to come up with 9.8m/s^2 of acceleration and only the margin above that is available for upward movement, where a traction system must only come up with the energy required to move.

At the moment of launch, Saturn V was 85% propellant by mass, with 6.5 million pounds of total vehicle weight (thus over 5.5 million pounds of propellant) and only 7.6 million pounds of thrust. So it could accelerate at one-sixth of a G at first, making it less than 15% efficient at the outset due to gravity drag, while 85% of what it lifted off the pad was fuel to be burned later. A rocket engine has a maximum raw efficiency of about 70% in converting fuel energy to thrust. Thus, the Saturn V's initial efficiency at lifting dry mass during the period of highest energy consumption was about 15% of about 15% of no more than 70%, or roughly 1.5%. And that does not distinguish between payload mass, the dry mass required to support the payload, and the dry mass required to support all the propellant.

To put it in automotive efficiency terms, Saturn V's first stage made 5 inches per gallon of kerosene and liquid oxygen during its entire flight profile, low and high efficiency extremes included.

"I'll answer your question with another question:"

Than' yuh vurra much, but I was hoping for my question to be answered by your answer. But it doesn't really matter, since I already knew that Gravity Drag cannot be eliminate either in a rocket or in your Orbit Elevator.

By the way, my original post featured the energy required to put PAYLOAD into orbit.

And my original post mentioned a SPACE PLANE.

Now to your "question-answer". My question was: "I will enjoy reading your detailed explanation of how you plan to avoid Gravity Drag." Or something like that, because in your post it sounded like you thought an Orbit Elevator could avoid it. You have so far failed to explain how an Orbit Elevator traction system turns off gravity. You did by fiat say that gravity does not drag the elevator down, but I already had it figured out that you believe that.

My understanding of an Orbit Elevator is that it would have ONE cable which is rigidly affixed to the Earth and also rigidly attached to the Low Earth Orbit satellite and attached to the higher counterweight satellite much higher (66,000 miles?). That is not the layout of an ordinary traction system in which there are moving cables. The traction system I have read of for an Orbit Elevator is for the car to have a gripping means which forcibly clamps onto the fixed "cable" and pulls the car up, possibly by a grooved or toothed wheel which also acts as the gripping means. Which is the layout you are seeing in your imagination, one similar to an everyday elevator with moving cables, or the one I just described with no moving cable?

By the way, you do realize that the fixed cable scheme with the gripping-powering wheel must have a motor in the car and either carry as much fuel as a rocket would need, or, be provided with electric power from the base of the cable? Electric power traveling through 22,000 miles? And of course you must have TWO cables, a hot wire and a ground wire? Of course you could carry a nuclear reactor in the car. That would have the public favor, wouldn't it....a ton of Plutonium dangling 22.000 miles overhead.

Forget about it! Better to continue to try to back engineer the antigravity motors of those flying saucers in A51.

 

[Arlo1]

FYI they plan to use lazers and beem the power from the ground to solar cells on the bottom. There was even a compatition for this and winnner got $120,000
Here is a raw video I will try to find the other one I watched. [youtube]VkdfuQdoW_Q[/youtube]

 

[doctorGONZO]

@Arlo
I became aware of this power transmission scheme in about 2005, give or take. It is an obvious solution. So I may have invented it before I heard about someone else thinking the same concept. It doesn't matter. I design engineered it far enough to run into so many practical problems that I gave up on it.

How much design engineering have you personally done on this concept?

Possibly not enough.

But what do I care. Be happy with your dream.

 

[Arlo1]

@Arlo
I became aware of this power transmission scheme in about 2005, give or take. It is an obvious solution. So I may have invented it before I heard about someone else thinking the same concept. It doesn't matter. I design engineered it far enough to run into so many practical problems that I gave up on it.

How much design engineering have you personally done on this concept?

Possibly not enough.

But what do I care. Be happy with your dream.

LOL oh its not my dream! I would never ride in an elevator that takes 8 days! It would be interesting to see space but I'm cautious about other peoples inventions.
I posted about this just because its pure crazy and new tech that's really cool to talk about.