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WERTMULLER'S EVALUATION This article - "Space Elevator Economics" - as presented before December 26 2005, was severely flawed.
First there was no consideration of dramatic improvements in alternative space technologies. For example, Bert Rutan's Space Ship One completed two flights to an altitude of 100 km and a speed of Mach 3 carrying a payload equal to three men at phenomenal low cost in just the past year. Space Ship One weighs less than 10 000 pounds. See Wikipedia "Scaled Composites SpaceShipOne". It is carried from the ground to a launch altitude of about forty thousand feet by a special mothership. Such "lift-launch" spacecraft are more efficient than simple rockets. Yet this technology was not compared at all to the space elevator. And "lift-launch orbiters" will surely be improved. Consider what Burt Rutan could launch if he leased and used the new Airbus A380 for his ground launch mothership. See Wikipedia "Airbus A380".
So the economics of other technologies has probably been mistated towards the high side. Meanwhile, the economics of the space elevator have undoubtedly been mistated on the low side due to mistakes regarding the basic physics of tethered space elevators. I will present the corrected physics here in this section. I recommend leaving the current mistakes in the "Physics" section unchanged so that new readers can comprehend what has transpired. The best way to understand everything is to perform "Gedanken" experiments......
You are floating in space in your space suit in absolutely perfect geosynchronous Earth orbit. You gently unholster your favorite weapon - a grenade launcher - and fire one off in precisely the opposite direction from Earth.
Conservation of momentum and energy together with Newton's Third Law means you move initially with a small constant linear velocity towards Earth. See Wikipedia "Newton's Laws of Motion". But you are in orbit! This means you have both linear and angular velocity relative to Earth. Your angular velocity is your number of orbits around Earth per unit of time - exactly one revolution per 24 hours at first. Your linear velocity in geosynchronous orbit is roughly 7 000 miles per hour - straight "east". You would fly off straight into space but gravity pulls you around in a circle. Newtonian physics dictates that this linear velocity remains unchanged unless some force changes it.
But you are moving closer to Earth because of the grenade so you are traveling around in a smaller and smaller circle around Earth. Smaller circle; Same linear speed. You circle the Earth in slightly less time. You are no longer in geosynchronous orbit.
You also are no longer "stabile". Since you travel around Earth in slightly less time, you have higher angular velocity hence higher centrifugal force. This higher centrifugal force throws you away from Earth counteracting the inward speed you got from your grenade. The grenade launch is actually a brief linear impulse which does not remain directed at the Earth's center as you fly around curving thru space, but we can ignore this non-Earth-centricity for a short time for simpler exposition with little error. In due time you stop moving in or out from Earth and stabilize in a lower, faster, non-geosynchronous orbit.
The exact same forces occur in reverse if you push yourself away from Earth, that is, if you fire a grenade towards Earth. You would keep the same linear velocity in a larger orbit; lose angular velocity; lose some slight centrifugal actually centripetal force; and stabilize at a higher, slower, non-geosynchronous orbit. Changes in angular velocity with changing orbital altitude is directly related to the Coriolis Effect. See Wikipedia "Coriolis Effect".
DEPLOYMENT
The forces described above greatly complicate the deployment of a tethered space elevator. Again we assume you are in perfect geosynchronous orbit. An alien from another galaxy drops off a complete space elevator kit without making the slightest gravitational wave or other distrubance. Following the included easily comprehended directions, you begin unwinding the thousands of miles of graphite ribbon. But the ribbon does not drop down to Earth.
No object changes its state of motion unless it is forced to do so. Newton's Laws. If you spin a reel of tether in space centripetal force will pull all the ribbon en masse off the reel in a tangled mess. It will not "unwind" like an elevator cable on Earth which is subject to constant gravitational acceleration - constant force. Hence some method of careful folding might be best when transporting space tether tape.
But then you must unfold it. It will not unfold itself. It will just "hang" there in orbit wherever some rocket unloaded it. Most likely you will use some kind of little rocket propelled tractor to pull the tape towards Earth. And you pull the other end away from Earth. And for every inch of movement, you encounter the exact same forces described above. Higher angular velocity in lower orbits destroying geosynchronicity. Rocket-propelled correction required. Continuously. During all unfolding and movement. Likewise lower angular velocity in higher orbit. Rocket firing will be required at both ends of the tape during all deployment movements. Thousands of miles. Hundreds of hours. Weeks. Months. A year?
The cost of this deployment operation was not even mentioned in the "Space Elevator" Wikipedia entry as it existed before December 26, 2005. And there is another cost underestimate which may be even more problematic. The December 25 2005 Wikipedia article contained these words:
"Launching Into Outer Space As a payload is lifted up a space elevator, it gains not only altitude but angular momentum as well. This angular momentum is taken from Earth's own rotation......"
The climber does not gain angular momentum solely from the Earth. Any object sitting on the surface of the earth at the equator is moving with angular velocity of exactly one revolution per 24 hours and a linear velocity of roughly 1 000 miles per hour. A satellite in perfect geosynchronous orbit also has an angular velocity of exactly one revolution per 24 hours but a linear velocity of roughly 7 000 miles per hour. Climbers do not obtain their velocity increase strictly from Earth. Every climber will distort the tape slightly and will pull on BOTH the elevator structure - including any counterweight - as well as the Earth. The climbers "want" to go "slower" slower angularlly as they go higher at every point. As climbers climb higher, more and more of this backward pull is levied upon the elevator and counterweight.
The backward pull slows the velocity of the entire elevator structure. The entire system - climber plus elevator - wants to rotate and "lie down" upon the Earth. The size of the backword force depends on how fast the climber climbs. If it goes up fast, it gains linear horizontal velocity faster which which requires greater horizontal force to create the acceleration. You cannot defeat Newton's Laws. A greater horizontal accelerating force on the climber means a greater horizontal retarding force on the Earth-Elevator system. The climber is accelerated to 7 000 mph and the elevator is correspondingly slowed, albeit less because of greater mass. Conservation of energy cannot be denied. The climber gains momentum and the elevator loses momentum. The elevator will have to be pulled back to proper velocity and position by a rocket motor firing at the far space end of the elevator during all climbing.
Thus both construction and operation of a tethered space elevator will be more costly than implied by the previous Wikipedia article.
There is an alternative. Attach a tether to the Moon instead of Earth. Allow a low orbit space station to "hang" close to Earth while dragged around from the Moon. The low altitude space station would be motionless relative to the Moon but would fly "backwards" relative to other Earth satellites. The Earth would be spinning around at a thousand miles per hour underneath the effectively motionless "satellite". Such a near-earth station would actually "hang" - it would not be held in place by centripetal force. The Earth would spin around every 24 hours below while the hanging station stayed motionless with the Moon. Low cost orbiters like Burt Rutan's Space Ship One could rendevzous with this slow moving space station just like fighter aircraft rendevzous with aerial tankers. There is still abundant uncertainty of cost and feasibility.
I posted the "anonymous economic evaluation" and herewith present an improved entry. Dudes: Somebody gotta post this in the main article. The Institute for Scientific Research is very nearly committing criminal fraud. IF NOT SEVERE ERROR, THEN con artistry. Capiche?
ECONOMICS RECONSIDERED
The Wikipedia Space Elevator article as presented before Christmas 2005 underestimates the cost of a tethered elevator due to a severe error in the basic physical design. The previous economic analysis also underestimates progress made with other technologies. See Wikipedia "Scaled Composites SpaceShipOne" and consider the added implications of the Wikipedia article "Airbus A380".
"Space Elevator" Section 2.5 contains the sentence "The angular momentum is taken from the Earth's own rotation." This is the same as saying that a bridge with two uneven supports - one larger than the other - is supported only by the larger support, which is absurd. Increased angular momentum is transferred to a climber via the Coriolis Effect. See Wikipedia "Coriolis Effect". Any climber on a space tether will gain angular momentum from both the Earth and the tether structure. The effect on the space end of the tether will be to pull it down and backward. The tether / counterweight structure will be pulled out of geosynchronous orbit. To pull it back will require a rocket motor firing nearly continuously at the space end of the tether. This implies enormous costs for fuel and refueling.
Installation of a tether involves similar problems. A reel of carbon tape unloaded from the Space Shuttle in geosynchronous orbit will not unwind itself. One end must be pulled into space with some kind of rocket tractor and the other end must be pulled to Earth. At all points of this unwinding operation the rocket tractors must compensate for the very same Coriolis effects. Installation thus means many many hours of very precise rocket firing with attendent costs. You cannot defeat conservation of energy. The Space Elevator disguises the energy of space acceleration as Coriolis Effect.
One possible alternative is to deploy a tether all the way from the Moon to somewhere near the Earth. A space station then might literally hang near Earth. It would not be held up by centrifugal force. It would actually hang from the Moon. It would be motionless relative to the Moon. The daily rotation of the Earth would make it appear as if this station was flying towards the west at 1 000 miles per hour. Low cost orbitors such as SpaceShipOne could then rendevzous with this station and from there pull cargo all the way to the Moon. The Moon would sacrifice an unmeasureable amount of momentum.
I offer another revision proposal for the Space Elevator article......
Climbers could be equipped with sideways firing rocket motors to combat the Coriolis Effect. Some have argued that uncompensated Coriolis Effects would ruin the entire Space Elevator system, causing a loss of geosynchronicity thereby forcing prohibitevly costly rocket-powered realigmnment of the tether and counterweight. To avoid disturbing the tether / counterweight system, each climber could have a small sideways-firing rocket capable of exactly countering any Coriolis effects generated by the climber.
Dudes, you gotta face the fact that as it now stands, the Space Elevator article / design is outrageously wrong. As pointed out in my previous posts, the Earth alone does not drag the climbers to higher angular momentum. That is the same as saying only one of two supports carries all the load on a bridge. The climbers exert Coriolois force on both the Earth and the counterweight ((or vice versa)) thereby gaining momentum. And the slightest distuturbance of counterweight geosynchronicity will need to be corrected at some point.
Brian Dunbar I greatly appreciate your replies. I want to repeat that I am complaining about such a primitive, pivotal error that it ALMOST looks like fraud. But I lean strongly toward believing in outrageous error. It has happened before. Constantly. Seems to be something human...... Therealhrw 08:55, 27 December 2005 (UTC)
A revision of my previous proposed main article revision:
Wolfkeeper's replies regarding orbital decay and elliptic orbits are well made "Econonmic Evaluation". But it is a fact that climbers *will* affect the motion of the space end of a space elevator. A climber nearing the geostation will exert a negative acceleration (negative with respective to orbital motion) on the station / counterweight due to Coriolis effects. This negative impulse will add a slight negative velocity to the far end of the structure. The entire structure will "try" to wrap itself around the Earth, albeit imperceptibly at first. The connection of the tether to the ground will prevent continued westward motion leading to complex counter forces. These counter forces and continued westward impulses from climbers will lead to a complex decay of the position and motion of the elevator.
If you say you are going to store so much energy in the station / counterweight system that all perturbations will be acceptably small even for so many - millions? - of tons of payload, you are saying you are going to fire rocket tractors for hours; days; weeks; months; hauling everything into place during construction and then use the stored energy later to climb into space without rockets.
Why? Why not just fire a rocket when you want to go into space? Like Burt Rutan?
There remains the possibility of building uniquely efficient rockets either for construction or Coriolis compensation. This is the subject of my "Wertmuller's Rockets" proposed revision. Please read it. --THEREALHRW
If no objection posted here in next couple days, I will attempt to create archive within this page; titled 'Newbie's Arguements"; and move all my spam-grade entrys and related replies thereto. This would be entries 29, 30, 31, 32 and 33. Therealhrw 09:30, 30 December 2005 (UTC)
A little explanation here regarding my arrogant irrational persistence. A long time ago I told Frank Thornburg about the space elevator from my si fi reading. He said it wouldn't work. Frank was a really heavy duty aerospace engineer who worked on the kind of stuff you cannot talk about. I effectively relayed his criticisms to you after only the barest skimming of the article. With what I knew and that "asteroid" top front on the article, it really looked like a bunch of cold fusion con artists dragging around some dumb wikipedians. You might remove the asteroid.
The section on "Launching Into Space" might be improved. You might write: The spaced elevator transmits forces in and out of the Earth as long as there is tension on the tether. A rough analogy would be a monorail with a sail hanging loosely underneath. If a wind blows the loose sail, it just flaps. But if the sail is weighted, any wind will push the monorail. The Earth is the monorail. The sail is the space elevator. The wind is the force added or subtracted to Earth's rotation by climbers going up and down.
Thank you all. I have learned about both space propulsion and wikipedians. Therealhrw 00:50, 31 December 2005 (UTC)
![]() | This page is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
WERTMULLER'S EVALUATION This article - "Space Elevator Economics" - as presented before December 26 2005, was severely flawed.
First there was no consideration of dramatic improvements in alternative space technologies. For example, Bert Rutan's Space Ship One completed two flights to an altitude of 100 km and a speed of Mach 3 carrying a payload equal to three men at phenomenal low cost in just the past year. Space Ship One weighs less than 10 000 pounds. See Wikipedia "Scaled Composites SpaceShipOne". It is carried from the ground to a launch altitude of about forty thousand feet by a special mothership. Such "lift-launch" spacecraft are more efficient than simple rockets. Yet this technology was not compared at all to the space elevator. And "lift-launch orbiters" will surely be improved. Consider what Burt Rutan could launch if he leased and used the new Airbus A380 for his ground launch mothership. See Wikipedia "Airbus A380".
So the economics of other technologies has probably been mistated towards the high side. Meanwhile, the economics of the space elevator have undoubtedly been mistated on the low side due to mistakes regarding the basic physics of tethered space elevators. I will present the corrected physics here in this section. I recommend leaving the current mistakes in the "Physics" section unchanged so that new readers can comprehend what has transpired. The best way to understand everything is to perform "Gedanken" experiments......
You are floating in space in your space suit in absolutely perfect geosynchronous Earth orbit. You gently unholster your favorite weapon - a grenade launcher - and fire one off in precisely the opposite direction from Earth.
Conservation of momentum and energy together with Newton's Third Law means you move initially with a small constant linear velocity towards Earth. See Wikipedia "Newton's Laws of Motion". But you are in orbit! This means you have both linear and angular velocity relative to Earth. Your angular velocity is your number of orbits around Earth per unit of time - exactly one revolution per 24 hours at first. Your linear velocity in geosynchronous orbit is roughly 7 000 miles per hour - straight "east". You would fly off straight into space but gravity pulls you around in a circle. Newtonian physics dictates that this linear velocity remains unchanged unless some force changes it.
But you are moving closer to Earth because of the grenade so you are traveling around in a smaller and smaller circle around Earth. Smaller circle; Same linear speed. You circle the Earth in slightly less time. You are no longer in geosynchronous orbit.
You also are no longer "stabile". Since you travel around Earth in slightly less time, you have higher angular velocity hence higher centrifugal force. This higher centrifugal force throws you away from Earth counteracting the inward speed you got from your grenade. The grenade launch is actually a brief linear impulse which does not remain directed at the Earth's center as you fly around curving thru space, but we can ignore this non-Earth-centricity for a short time for simpler exposition with little error. In due time you stop moving in or out from Earth and stabilize in a lower, faster, non-geosynchronous orbit.
The exact same forces occur in reverse if you push yourself away from Earth, that is, if you fire a grenade towards Earth. You would keep the same linear velocity in a larger orbit; lose angular velocity; lose some slight centrifugal actually centripetal force; and stabilize at a higher, slower, non-geosynchronous orbit. Changes in angular velocity with changing orbital altitude is directly related to the Coriolis Effect. See Wikipedia "Coriolis Effect".
DEPLOYMENT
The forces described above greatly complicate the deployment of a tethered space elevator. Again we assume you are in perfect geosynchronous orbit. An alien from another galaxy drops off a complete space elevator kit without making the slightest gravitational wave or other distrubance. Following the included easily comprehended directions, you begin unwinding the thousands of miles of graphite ribbon. But the ribbon does not drop down to Earth.
No object changes its state of motion unless it is forced to do so. Newton's Laws. If you spin a reel of tether in space centripetal force will pull all the ribbon en masse off the reel in a tangled mess. It will not "unwind" like an elevator cable on Earth which is subject to constant gravitational acceleration - constant force. Hence some method of careful folding might be best when transporting space tether tape.
But then you must unfold it. It will not unfold itself. It will just "hang" there in orbit wherever some rocket unloaded it. Most likely you will use some kind of little rocket propelled tractor to pull the tape towards Earth. And you pull the other end away from Earth. And for every inch of movement, you encounter the exact same forces described above. Higher angular velocity in lower orbits destroying geosynchronicity. Rocket-propelled correction required. Continuously. During all unfolding and movement. Likewise lower angular velocity in higher orbit. Rocket firing will be required at both ends of the tape during all deployment movements. Thousands of miles. Hundreds of hours. Weeks. Months. A year?
The cost of this deployment operation was not even mentioned in the "Space Elevator" Wikipedia entry as it existed before December 26, 2005. And there is another cost underestimate which may be even more problematic. The December 25 2005 Wikipedia article contained these words:
"Launching Into Outer Space As a payload is lifted up a space elevator, it gains not only altitude but angular momentum as well. This angular momentum is taken from Earth's own rotation......"
The climber does not gain angular momentum solely from the Earth. Any object sitting on the surface of the earth at the equator is moving with angular velocity of exactly one revolution per 24 hours and a linear velocity of roughly 1 000 miles per hour. A satellite in perfect geosynchronous orbit also has an angular velocity of exactly one revolution per 24 hours but a linear velocity of roughly 7 000 miles per hour. Climbers do not obtain their velocity increase strictly from Earth. Every climber will distort the tape slightly and will pull on BOTH the elevator structure - including any counterweight - as well as the Earth. The climbers "want" to go "slower" slower angularlly as they go higher at every point. As climbers climb higher, more and more of this backward pull is levied upon the elevator and counterweight.
The backward pull slows the velocity of the entire elevator structure. The entire system - climber plus elevator - wants to rotate and "lie down" upon the Earth. The size of the backword force depends on how fast the climber climbs. If it goes up fast, it gains linear horizontal velocity faster which which requires greater horizontal force to create the acceleration. You cannot defeat Newton's Laws. A greater horizontal accelerating force on the climber means a greater horizontal retarding force on the Earth-Elevator system. The climber is accelerated to 7 000 mph and the elevator is correspondingly slowed, albeit less because of greater mass. Conservation of energy cannot be denied. The climber gains momentum and the elevator loses momentum. The elevator will have to be pulled back to proper velocity and position by a rocket motor firing at the far space end of the elevator during all climbing.
Thus both construction and operation of a tethered space elevator will be more costly than implied by the previous Wikipedia article.
There is an alternative. Attach a tether to the Moon instead of Earth. Allow a low orbit space station to "hang" close to Earth while dragged around from the Moon. The low altitude space station would be motionless relative to the Moon but would fly "backwards" relative to other Earth satellites. The Earth would be spinning around at a thousand miles per hour underneath the effectively motionless "satellite". Such a near-earth station would actually "hang" - it would not be held in place by centripetal force. The Earth would spin around every 24 hours below while the hanging station stayed motionless with the Moon. Low cost orbiters like Burt Rutan's Space Ship One could rendevzous with this slow moving space station just like fighter aircraft rendevzous with aerial tankers. There is still abundant uncertainty of cost and feasibility.
I posted the "anonymous economic evaluation" and herewith present an improved entry. Dudes: Somebody gotta post this in the main article. The Institute for Scientific Research is very nearly committing criminal fraud. IF NOT SEVERE ERROR, THEN con artistry. Capiche?
ECONOMICS RECONSIDERED
The Wikipedia Space Elevator article as presented before Christmas 2005 underestimates the cost of a tethered elevator due to a severe error in the basic physical design. The previous economic analysis also underestimates progress made with other technologies. See Wikipedia "Scaled Composites SpaceShipOne" and consider the added implications of the Wikipedia article "Airbus A380".
"Space Elevator" Section 2.5 contains the sentence "The angular momentum is taken from the Earth's own rotation." This is the same as saying that a bridge with two uneven supports - one larger than the other - is supported only by the larger support, which is absurd. Increased angular momentum is transferred to a climber via the Coriolis Effect. See Wikipedia "Coriolis Effect". Any climber on a space tether will gain angular momentum from both the Earth and the tether structure. The effect on the space end of the tether will be to pull it down and backward. The tether / counterweight structure will be pulled out of geosynchronous orbit. To pull it back will require a rocket motor firing nearly continuously at the space end of the tether. This implies enormous costs for fuel and refueling.
Installation of a tether involves similar problems. A reel of carbon tape unloaded from the Space Shuttle in geosynchronous orbit will not unwind itself. One end must be pulled into space with some kind of rocket tractor and the other end must be pulled to Earth. At all points of this unwinding operation the rocket tractors must compensate for the very same Coriolis effects. Installation thus means many many hours of very precise rocket firing with attendent costs. You cannot defeat conservation of energy. The Space Elevator disguises the energy of space acceleration as Coriolis Effect.
One possible alternative is to deploy a tether all the way from the Moon to somewhere near the Earth. A space station then might literally hang near Earth. It would not be held up by centrifugal force. It would actually hang from the Moon. It would be motionless relative to the Moon. The daily rotation of the Earth would make it appear as if this station was flying towards the west at 1 000 miles per hour. Low cost orbitors such as SpaceShipOne could then rendevzous with this station and from there pull cargo all the way to the Moon. The Moon would sacrifice an unmeasureable amount of momentum.
I offer another revision proposal for the Space Elevator article......
Climbers could be equipped with sideways firing rocket motors to combat the Coriolis Effect. Some have argued that uncompensated Coriolis Effects would ruin the entire Space Elevator system, causing a loss of geosynchronicity thereby forcing prohibitevly costly rocket-powered realigmnment of the tether and counterweight. To avoid disturbing the tether / counterweight system, each climber could have a small sideways-firing rocket capable of exactly countering any Coriolis effects generated by the climber.
Dudes, you gotta face the fact that as it now stands, the Space Elevator article / design is outrageously wrong. As pointed out in my previous posts, the Earth alone does not drag the climbers to higher angular momentum. That is the same as saying only one of two supports carries all the load on a bridge. The climbers exert Coriolois force on both the Earth and the counterweight ((or vice versa)) thereby gaining momentum. And the slightest distuturbance of counterweight geosynchronicity will need to be corrected at some point.
Brian Dunbar I greatly appreciate your replies. I want to repeat that I am complaining about such a primitive, pivotal error that it ALMOST looks like fraud. But I lean strongly toward believing in outrageous error. It has happened before. Constantly. Seems to be something human...... Therealhrw 08:55, 27 December 2005 (UTC)
A revision of my previous proposed main article revision:
Wolfkeeper's replies regarding orbital decay and elliptic orbits are well made "Econonmic Evaluation". But it is a fact that climbers *will* affect the motion of the space end of a space elevator. A climber nearing the geostation will exert a negative acceleration (negative with respective to orbital motion) on the station / counterweight due to Coriolis effects. This negative impulse will add a slight negative velocity to the far end of the structure. The entire structure will "try" to wrap itself around the Earth, albeit imperceptibly at first. The connection of the tether to the ground will prevent continued westward motion leading to complex counter forces. These counter forces and continued westward impulses from climbers will lead to a complex decay of the position and motion of the elevator.
If you say you are going to store so much energy in the station / counterweight system that all perturbations will be acceptably small even for so many - millions? - of tons of payload, you are saying you are going to fire rocket tractors for hours; days; weeks; months; hauling everything into place during construction and then use the stored energy later to climb into space without rockets.
Why? Why not just fire a rocket when you want to go into space? Like Burt Rutan?
There remains the possibility of building uniquely efficient rockets either for construction or Coriolis compensation. This is the subject of my "Wertmuller's Rockets" proposed revision. Please read it. --THEREALHRW
If no objection posted here in next couple days, I will attempt to create archive within this page; titled 'Newbie's Arguements"; and move all my spam-grade entrys and related replies thereto. This would be entries 29, 30, 31, 32 and 33. Therealhrw 09:30, 30 December 2005 (UTC)
A little explanation here regarding my arrogant irrational persistence. A long time ago I told Frank Thornburg about the space elevator from my si fi reading. He said it wouldn't work. Frank was a really heavy duty aerospace engineer who worked on the kind of stuff you cannot talk about. I effectively relayed his criticisms to you after only the barest skimming of the article. With what I knew and that "asteroid" top front on the article, it really looked like a bunch of cold fusion con artists dragging around some dumb wikipedians. You might remove the asteroid.
The section on "Launching Into Space" might be improved. You might write: The spaced elevator transmits forces in and out of the Earth as long as there is tension on the tether. A rough analogy would be a monorail with a sail hanging loosely underneath. If a wind blows the loose sail, it just flaps. But if the sail is weighted, any wind will push the monorail. The Earth is the monorail. The sail is the space elevator. The wind is the force added or subtracted to Earth's rotation by climbers going up and down.
Thank you all. I have learned about both space propulsion and wikipedians. Therealhrw 00:50, 31 December 2005 (UTC)