Re: Space elevator tech implementations
I am going to combine the two most recent space elevator threads later today or tomorrow.
I am going to combine the two most recent space elevator threads later today or tomorrow.
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Re: Space elevator tech implementations
I still see dropping a 20-30 thousand mile long super strong cable from GS orbit as a recipe for disaster. If somehow they lost control how long would that cable whip around in the atmosphere and what possible damage could it do to both aircraft and on the ground?
I still see dropping a 20-30 thousand mile long super strong cable from GS orbit as a recipe for disaster. If somehow they lost control how long would that cable whip around in the atmosphere and what possible damage could it do to both aircraft and on the ground?
Re: Space elevator tech implementations
Excuse me, but why talk only about Earth based space elevators ? What about Moon elevator or asteroid elevators ? They could be made with existing materials, at least i think so.
Building them would also add to experience in building, operation and all other related knowledge.
Excuse me, but why talk only about Earth based space elevators ? What about Moon elevator or asteroid elevators ? They could be made with existing materials, at least i think so.
Building them would also add to experience in building, operation and all other related knowledge.
Moon elevator should be much much longer than Earth-based elevator. Moon is rotating only once per 27 days. Asteroids are different matter.
Re: Space elevator tech implementations
Point taken. The design requires further working.
I had no idea the book made them so massive.
The bobbing up and down could be an energy source, compressing gas or regular atmosphere on the down stroke and making low pressure on the up. If the bore and stroke, to use piston terminology, is several city blocks and a few metres, and air is not just sucked in through a one-way valve but forcibly pumped in, a massive amount of energy is generated. In the event of earth-quaking, it is the Compressing Chamber that breaks. If the bottom of the cable is in water, say, 109 degrees East (between Singapore and Borneo) or Lake Tanzania for potable water, then a large volume of water can be pushed into a long thin cylinder and propel an elevator car some of the way.
Which is worse: the cable bends; the cable doesn't bend?
Since the cable can't break and assuming it doesn't bend it has four states:
Balanced and upright between skies and earth;
Flying off into space;
Piercing the earth like a well-thrown javelin;
Seesawing like a javelin resting and balancing on a basketball.
Whether its final position is piercing or seesawing, only a tiny portion of it is touching the earth. The worst seesawing resting place maybe is between and south of Greenland and Iceland and aligned north-south. It would disrupt North Atlantic shipping and be of least use as a launch ramp because it points to both poles. The ideal finishing place would seem to be located between Antarctica on one side and Tierra del Fuego and Cape of Good Hope on the other. It points East-West and is fairly well out of the way. Falling from the above-mentioned places, it goes over the Andes and Mt. Kilimanjaro, then Australia, Argentina, Zimbabwe, then into the Southern Ocean coming to rest by South America.
It would take some time to fall from balance. If sufficient weight at the bottom end could be hurriedly removed from the structure, the weight distribution would change and the structure rise rather than fall.
David C
willpittenger":37qu0nb4 said:
Point taken. The design requires further working.
I had no idea the book made them so massive.
The bobbing up and down could be an energy source, compressing gas or regular atmosphere on the down stroke and making low pressure on the up. If the bore and stroke, to use piston terminology, is several city blocks and a few metres, and air is not just sucked in through a one-way valve but forcibly pumped in, a massive amount of energy is generated. In the event of earth-quaking, it is the Compressing Chamber that breaks. If the bottom of the cable is in water, say, 109 degrees East (between Singapore and Borneo) or Lake Tanzania for potable water, then a large volume of water can be pushed into a long thin cylinder and propel an elevator car some of the way.
bdewoody":37qu0nb4 said:
Which is worse: the cable bends; the cable doesn't bend?
Since the cable can't break and assuming it doesn't bend it has four states:
Balanced and upright between skies and earth;
Flying off into space;
Piercing the earth like a well-thrown javelin;
Seesawing like a javelin resting and balancing on a basketball.
Whether its final position is piercing or seesawing, only a tiny portion of it is touching the earth. The worst seesawing resting place maybe is between and south of Greenland and Iceland and aligned north-south. It would disrupt North Atlantic shipping and be of least use as a launch ramp because it points to both poles. The ideal finishing place would seem to be located between Antarctica on one side and Tierra del Fuego and Cape of Good Hope on the other. It points East-West and is fairly well out of the way. Falling from the above-mentioned places, it goes over the Andes and Mt. Kilimanjaro, then Australia, Argentina, Zimbabwe, then into the Southern Ocean coming to rest by South America.
It would take some time to fall from balance. If sufficient weight at the bottom end could be hurriedly removed from the structure, the weight distribution would change and the structure rise rather than fall.
David C
Re: Space elevator tech implementations
That was kind of my line of thinking with having the counterbalance tether be retractable/extendable. You could add or remove tension/lift from the cable/javelin.
That was kind of my line of thinking with having the counterbalance tether be retractable/extendable. You could add or remove tension/lift from the cable/javelin.
There's actually a subtle difference between geosynchonous and geostationary.
Geostationary orbits must be over the equator and stay more or less over the same place on the surface on the equator. Geosynchronous techinically means that the orbit passes over the same longitude on earth avery day at the same time. They are related, but not the same.
Those posting here with ideas should probably try and understand the difference.
Wiki can help
http://en.wikipedia.org/wiki/Geosynchronous_orbit
Geostationary orbits must be over the equator and stay more or less over the same place on the surface on the equator. Geosynchronous techinically means that the orbit passes over the same longitude on earth avery day at the same time. They are related, but not the same.
Those posting here with ideas should probably try and understand the difference.
Wiki can help
http://en.wikipedia.org/wiki/Geosynchronous_orbit
I should point out that most of the geostationary locations are filled, and that geosyncronous orbits, being basically at the same height would run the risk of plowing into them....
MeteorWayne":37eqjgsb said:
For something this important, room can be made. The elevator operator would be in a position to offer multiple free launches to the person willing to move/deorbit their satellite. I have a hard time understanding any ideas that don't involve a geostationary orbit. I mean, you're going to carry payloads to the elevator at mach-something and offload them in flight? Seems to me you should just get a 99 year lease on some equatorial space and slow-boat the cargo over there.
Obviously the balloons construction idea was kind of silly, the only way I see that being useful is that you could construct from above down to some point well above the ground for safety reasons, and then construct from the bottom up for the remaining distance using balloons.
Would it help to anchor the cable on an angle to reduce bowing and movement or would it much matter?
What I mean is the below (apologies for the lack of scale)
This could also mean the cable could extend out along earth's surface for some distance, and you could get going quite fast laterally on the ground before heading up the cable, reducing the power needed to head straight up from a stop.
In other words, if you had a space train that could get going very quickly (mag lev or some such) that would streak along the ground and head up the cable at a gradual angle. Probably horrifically dangerous, but it would be one hell of a ride!
And at some point would the centrifugal force start to help you, not by pushing you out per say, but by pulling the cable back as you head up it? I need help with the physics!
What I mean is the below (apologies for the lack of scale)
This could also mean the cable could extend out along earth's surface for some distance, and you could get going quite fast laterally on the ground before heading up the cable, reducing the power needed to head straight up from a stop.
In other words, if you had a space train that could get going very quickly (mag lev or some such) that would streak along the ground and head up the cable at a gradual angle. Probably horrifically dangerous, but it would be one hell of a ride!
And at some point would the centrifugal force start to help you, not by pushing you out per say, but by pulling the cable back as you head up it? I need help with the physics!
tanstaafl76":s57nwmnk said:Would it help to anchor the cable on an angle to reduce bowing and movement or would it much matter?
What I mean is the below (apologies for the lack of scale)
This could also mean the cable could extend out along earth's surface for some distance, and you could get going quite fast laterally on the ground before heading up the cable, reducing the power needed to head straight up from a stop.
In other words, if you had a space train that could get going very quickly (mag lev or some such) that would streak along the ground and head up the cable at a gradual angle. Probably horrifically dangerous, but it would be one hell of a ride!
And at some point would the centrifugal force start to help you, not by pushing you out per say, but by pulling the cable back as you head up it? I need help with the physics!
Don't worry. Help is coming.
Make a simple test. Take a rope. Attatch some weight to the end of it. Now spin it - it'll strighten up. Now try to spin it under angle as you described. If you manage to do it constantly, write a dissertation about it and You'll get Nobel price because you have disproven Newtonian physics and that is groundbraking.
Before proceeding with the reinvention of the space elevator, It'd be good to read some stuff written by Brad Edwards. Book is good, but NIAC reports do the work as well. Last one is here: http://www.niac.usra.edu/studies/521Edwards.html
Sorry for the tangent, but is a launch loop really so much more feasible?
http://www.examiner.com/x-23511-Portlan ... ace-travel
Sorry I had a brain fart but my point was that the elevator has to remain over the same point on the equator not over Scandinavia.MeteorWayne":1o3ap8bj said:There's actually a subtle difference between geosynchonous and geostationary.
Geostationary orbits must be over the equator and stay more or less over the same place on the surface on the equator. Geosynchronous techinically means that the orbit passes over the same longitude on earth avery day at the same time. They are related, but not the same.
Those posting here with ideas should probably try and understand the difference.
Wiki can help
http://en.wikipedia.org/wiki/Geosynchronous_orbit
Reading about the launch loop gave me flashbacks to this scene in Contact....
http://www.youtube.com/watch?v=bdcE3VyKv5U
http://www.youtube.com/watch?v=bdcE3VyKv5U
tanstaafl76":22ql410d said:
That'd be very stiff material. Very-very stiff. Other option is to use another tether anchored elsewhere. Either way I don't see the point. Why?
Just trying to think of a way that lateral speed on the surface could be utilized to gain altitude and thus reduce the power requirement of an elevator that would go straight up.
tanstaafl76":2cyr4j04 said:
WEll, it does because the higher the glimber gets on the rope, the smaller is the gravity pull (cause the centrifugal force is becoming larger). Essentially becoming 0 in the GEO.
Yes, 30,000 kilometer with a very massive counterweight. 91,000 kilometers with a modest counterweight. Even longer, means the far end is faster, allowing anywhere in the inner solar system with a tiny bit of mid course correction fuel. I agree, the savings are tiny going to LEO, but they are fabulous going farther from Earth. It appears the space elevator can be anchored as much as 2000 kilometers from the equator, but there are disadvantages that increase with distance from the equator. There are lots of details in the forum at http://www.liftport.com
Long CNT = carbon nano tubes with great specs is the principle barrier to starting construction, of a space elevator. That could happen tomorrow or 2099. Most of the other details are unproven, but look good in theory. I recommend funding for the other details and for simulations, such as a rotating (end over end) tether a few kilometers long in LEO.
The launch loop would be increadibly expensive and most of the details are unproven, but I agree, they look good in theory. Any idea how to simulate a launchloop? We might have to start building ten before we got a working launch loop. Neil
Long CNT = carbon nano tubes with great specs is the principle barrier to starting construction, of a space elevator. That could happen tomorrow or 2099. Most of the other details are unproven, but look good in theory. I recommend funding for the other details and for simulations, such as a rotating (end over end) tether a few kilometers long in LEO.
The launch loop would be increadibly expensive and most of the details are unproven, but I agree, they look good in theory. Any idea how to simulate a launchloop? We might have to start building ten before we got a working launch loop. Neil
After skimming over this thread, I did not see any mention of Arthur C. Clarke's "The Fountains Of Paradise", which provides an excellent treatment of the construction of a space elevator. Since few people here are likely to read it, I will try to provide a synopsis.
Development of an ultra-strong synthetic material (Clarke used diamond monofilament) is made possible by zero-gravity manufacturing. Starting from geosynchronous orbit (which I call the Clarke orbit, because it is easier to spell,) two tapes, or cables, are constructed, one going up, the other going down. The mass of the structure must be kept in equilibrium to prevent it from wandering off station. A counterweight of several million tons is attached to the upper end as the lower end is anchored on Earth. The structure is a square tube, with tracks running up each side. Payloads are not lifted, they propel themselves up the tower, or are allowed to descend with braking forces. (Regenerative braking is used to capture energy.) Payload costs are equivalent to running an electrical motor of a few horsepower for about 30 hours, because the vehicle is not having to hold itself up against gravity, nor does it have to deal with atmospheric resistance. Payloads for other planets can be launched by the tower acting as a sling.
Breakage of the tower does not result in the whole thing falling down, because the upper portion is kept in orbit by its velocity. Only the lower few miles of the tower is subject to atmospheric disturbances, which would be the most likely cause of a failure. The tower would be a flexible structure, which would result in bowing, or distortion, as payloads ascend and descend. The capability of launching payloads by sling is limited because of the energy transfers involved, which cannot exceed certain values.
Clarke took a huge leap of speculation in '3001', supposing that it would be possible to connect towers together at the Clarke orbit altitude, eventually forming a ring around the planet. The towers are still supported by the orbital structure, and are not held up from below.
Manufacture of the material used to support the structure is almost certainly going to have to happen in space, because thousands of miles of CONTINUOUS cable is required, and the cable must have a tensile strength of thousands of tons per inch. The amount of carbon required, as well as the energy needed to process it, makes it unlikely to happen on Earth, even if the problems of gravity effects on the manufacture of the cable could be overcome.
Once constructed, no other method of reaching space could be as cheap as the tower, because any vehicle must hold itself up against gravity while traversing the portion of the atmosphere which is too dense to pass through at high velocity. A vehicle climbing the tower only needs enough energy to climb against gravity, not to hold itself up as well as climb.
Don't expect to see a space elevator in construction until we have cheap and easy access to space. But the amount of commerce which will happen between Earth and space will eventually not only justify constructing an elevator, but necessitate it. Where one or two people used to walk or ride horseback, now thousands travel at a time. The same will be true with space. Where one or two traveled by rocket, someday thousands will ride by elevator.
Development of an ultra-strong synthetic material (Clarke used diamond monofilament) is made possible by zero-gravity manufacturing. Starting from geosynchronous orbit (which I call the Clarke orbit, because it is easier to spell,) two tapes, or cables, are constructed, one going up, the other going down. The mass of the structure must be kept in equilibrium to prevent it from wandering off station. A counterweight of several million tons is attached to the upper end as the lower end is anchored on Earth. The structure is a square tube, with tracks running up each side. Payloads are not lifted, they propel themselves up the tower, or are allowed to descend with braking forces. (Regenerative braking is used to capture energy.) Payload costs are equivalent to running an electrical motor of a few horsepower for about 30 hours, because the vehicle is not having to hold itself up against gravity, nor does it have to deal with atmospheric resistance. Payloads for other planets can be launched by the tower acting as a sling.
Breakage of the tower does not result in the whole thing falling down, because the upper portion is kept in orbit by its velocity. Only the lower few miles of the tower is subject to atmospheric disturbances, which would be the most likely cause of a failure. The tower would be a flexible structure, which would result in bowing, or distortion, as payloads ascend and descend. The capability of launching payloads by sling is limited because of the energy transfers involved, which cannot exceed certain values.
Clarke took a huge leap of speculation in '3001', supposing that it would be possible to connect towers together at the Clarke orbit altitude, eventually forming a ring around the planet. The towers are still supported by the orbital structure, and are not held up from below.
Manufacture of the material used to support the structure is almost certainly going to have to happen in space, because thousands of miles of CONTINUOUS cable is required, and the cable must have a tensile strength of thousands of tons per inch. The amount of carbon required, as well as the energy needed to process it, makes it unlikely to happen on Earth, even if the problems of gravity effects on the manufacture of the cable could be overcome.
Once constructed, no other method of reaching space could be as cheap as the tower, because any vehicle must hold itself up against gravity while traversing the portion of the atmosphere which is too dense to pass through at high velocity. A vehicle climbing the tower only needs enough energy to climb against gravity, not to hold itself up as well as climb.
Don't expect to see a space elevator in construction until we have cheap and easy access to space. But the amount of commerce which will happen between Earth and space will eventually not only justify constructing an elevator, but necessitate it. Where one or two people used to walk or ride horseback, now thousands travel at a time. The same will be true with space. Where one or two traveled by rocket, someday thousands will ride by elevator.
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