Re: Nanotube cable will connect Earth and Luna
Nano-transistor self-assembles using biology 19:00 20 November 03 NewScientist.com news service http://www.newscientist.com/news/news.jsp?id=ns4406 There will be some pretty weird stuff happening over the next decade or so. I sometimes wonder if we'll get our carbon nanotube fiber from biological systems in the end. Much depends on whether we'll see Moore's Law-type effects in this technology. Moore's Law depends on the highly parallel nature of photolithography and chemistry, on carving structures into planar surfaces by exposure of substances to light patterns. Biotech depends more on the exponential growth curves of microorganism cultures and DNA can do 3-dimensional construction, not just 2D. One of the founders of Intel said they had trouble predicting anything in their technology more than 7 years out, even with the driving forces pretty well understood. I really wonder if anyone knows what's going to happen at the biotech/nanotech interface even 3 years out, at this rate. For all we know, space elevator reasoning may seem crudely extrapolative in 10 years, with either much better approaches discovered, or all hopes dashed. -michael turner [EMAIL PROTECTED] == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: Nanotube cable will connect Earth and Luna
(BYet another afterthought: Ray Bradbury coined the phrase, "From romance to (Breality," with the implicit suggestion that the romance can be retained in (Bthe process. Real life is seldom like that, however. (B (BIs there anything less romantic than a civil engineering project? And yet, (Bthat's ultimately what the space elevator would be. (B (BRockets had romance ... for a while. The Shuttle mated the enduring romance (Bof winged flight to the fading romance of the rocketship concept, but look (Bwhat it's come to. It collided with realities, including many political (Brealities, and recently collided with pieces of itself, with disastrous (Bconsequences. Where romance and reality are at cross purposes, I'll always (Bgo with reality in the end. (B (BThe space elevator is very exciting from a pure engineering point of view. (BBut it would still be an elevator: fundamentally inelegant, functional, (Bslow, brute force. (The "brute force" in this case being interatomic forces (Bin carbon lattices.) The real fun won't start for most until someone steps (Bout on the top floor. Until then, the fun is in helping in its design. One (Bof the sharper aerospace engineers of my acquaintance told me once that when (Bhe sees the Shuttle on the launch pad, he's looking at the gantry, not the (Bship. That's the mentality required, I think. (B (B-michael turner (B[EMAIL PROTECTED] (B (B (B- Original Message - (BFrom: "Joe Latrell" [EMAIL PROTECTED] (BTo: "Europa IcePIC mailing list" [EMAIL PROTECTED] (BSent: Thursday, November 20, 2003 2:27 PM (BSubject: Re: Nanotube cable will connect Earth and Luna (B (B (B (B Don't get me wrong here and maybe I am being a bit slow here, but I have (B some issues that just keep bugging me about the concept of a space (B elevator. (B (B 1. How do you get it down in the first place. Upper atmosphere winds (B can move at over 150 MPH. How do you get a ribbon through that without (B it whipping so bad that it either tears itself apart or will be (B impossible to catch. A simple issue but one that is troubling. (B (B 2. What about the electrical discharge from something like that (B connecting to the earth. Over that distance the static charge alone (B could blow the thing apart when it connects to the ground. No one has (B ever explained how to solve this to me in a way that amde sense. (B (B 3. Orbital mechanics are pretty picky. Pertibations of the orbit alone (B will account for hundreds of meters of slack/tension. What do you do, (B spool it up when it goes slack? Now the anchoring system has to be able (B to wind up and down too? (B (B 4. This cable/ribbon will have to undergo a large amount of both (B tension and compression from multiple angles. I don't know that (B nanotubes are tested in a fabric mode that could provide for all of (B these forces. I have also heard that if the ribbon does snap, it will (B remain stationary and can be repaired. Stationary to what? Again the (B speeds involved with pertibation and wind forces, it will not remain (B stationary for very long. (B (B I really want to believe in the space elevator but so far, these (B questions are unanswered and untested. Anyone have ideas or am I just (B being a wet blanket? (B (B Joe L. (B (B On Wed, 2003-11-19 at 21:53, Michael Turner wrote: (B My take on this: the right kind of space elevator need not compete for (B orbital space with an Earth-Moon tether. A space elevator moving in the (B equatorial plane of the Moon could be an enabling technology for (Bbuilding (B the Earth-Moon tether, since it's probably the cheapest per pound way to (Bget (B both to Earth-Moon L1 and to the surface of the Moon. It makes sense to (B think more in terms of how they might be complementary than competing. (B (B Designs I've seen so far for space elevators assume they are tethered to (Bthe (B Earth, and have an equatorial orbit for their center of mass. However, (B geosynchronous orbits don't have to be equatorial orbits. The Earth is (B tilted with respect to the Earth-Moon orbital plane, so a space elevator (B tethered to the Earth would either have to pendulum, or the tip of it (Bwould (B have to travel north and south through the atmosphere, making a round (Btrip (B every 24 hours. (B (B A space elevator "ground floor" that travels thousands of miles a day is (B still moving slowly enough for a jet plane, and maybe a helicopter, to (Breach (B it, a small added cost. A pendulum approach might not work -- anchoring (Bit (B might be too hard, and might introduce angles that conflict with an (B Earth-Moon tether. I don't this means we shouldn't do an anchored (Belevator, (B starting with equatorial orbit. Just that it should be designed so that (Bit (B can be unhooked and moved to an Earth-Moon orbital plane later wit
Re: Nanotube cable will connect Earth and Luna
--- Michael Turner [EMAIL PROTECTED] wrote: I don't know how much perturbation is expected, but remember that the center of mass is about 23,000 miles out. At those distances, GEO satellites carry rather small engines to correct for perturbations that accumulate over *decades* of operation. Presumably, being a ribbon, it also has some elasticity, and over tens of thousands of miles, you'll probably just see some slight variations in tension. Note that the orbital perturbations seen in GEO satellites must be corrected, otherwise they'll drift out of range of fixed dishes. But if you get some drift in the center of mass of a space elevator, the next question is not how do we correct it? It's so what? This reminds me -- It's been at least ten years since I read the book, but in Arthur C. Clarke's _The Fountains Of Paradise_, IIRC, they talked about another cause of drift (swaying) of the elevator, which is the up and down motion of the elevator cars. In fact, when they built a space elevator on Mars, they actually planned on timing the motions of the cars continually to cause the elevator to swing wide of Mars' moons, Phobos and Deimos, since it proved necessary to build the elevators out past their mean orbits. Wild stuff. Their attitude on the drift was even better than so what -- they used it to their advantage. That's IIRC. --Mark __ Do you Yahoo!? Free Pop-Up Blocker - Get it now http://companion.yahoo.com/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: Nanotube cable will connect Earth and Luna
, the real problems will come from very unexpected directions. -michael turner [EMAIL PROTECTED] Joe L. On Wed, 2003-11-19 at 21:53, Michael Turner wrote: My take on this: the right kind of space elevator need not compete for orbital space with an Earth-Moon tether. A space elevator moving in the equatorial plane of the Moon could be an enabling technology for building the Earth-Moon tether, since it's probably the cheapest per pound way to get both to Earth-Moon L1 and to the surface of the Moon. It makes sense to think more in terms of how they might be complementary than competing. Designs I've seen so far for space elevators assume they are tethered to the Earth, and have an equatorial orbit for their center of mass. However, geosynchronous orbits don't have to be equatorial orbits. The Earth is tilted with respect to the Earth-Moon orbital plane, so a space elevator tethered to the Earth would either have to pendulum, or the tip of it would have to travel north and south through the atmosphere, making a round trip every 24 hours. A space elevator ground floor that travels thousands of miles a day is still moving slowly enough for a jet plane, and maybe a helicopter, to r each it, a small added cost. A pendulum approach might not work -- anchoring it might be too hard, and might introduce angles that conflict with an Earth-Moon tether. I don't this means we shouldn't do an anchored elevator, starting with equatorial orbit. Just that it should be designed so that it can be unhooked and moved to an Earth-Moon orbital plane later with relatively little trouble. Having a space elevator in the Earth-Moon equatorial plane is the first approximation to reducing the chance of an Earth-Moon tether and the space elevator ribbon crossing. aking the elevator ground floor mobile rather than fixed further reduces the intersection space. A second approximation might be to attach the Moon end of the Earth-Moon tether to one of the Moon's poles. This introduces a small angle. Finally, there's the issue of whether the Earth-Moon tether can be attached to the Earth, or whether it should just dangle outside the atmosphere. If the tip of the Earth-Moon tether is near the equator, there's a relative speed of about 1000 miles per hour. Consider, however, that once you're in an aerodynamic regime of any kind, all the rules change. As you get further into the atmosphere, you can use relative speed for aerodynamic lift, and rudders can steer the tether away from the equator, moving the tip into higher latitudes where the relative speed is much slower. The problems of attachment appear at the poles -- a relative tether-tip/atmosphere velocity that might become sub-aerodynamic. However, near those speeds, conventional aircraft could rendezvous with the tip, an attachment to the Earth would be unnecessary. One could imagine a standard cargo freight plane hovering over a landing pad at near stall speeds, then just touching down -- you wouldn't need something like an aircraft carrier dangling out there. The Earth-Moon's Earthside tether tip problems are further favored by being in an aerodynamic regime, because, unlike the space elevator's center of mass, the distance to the Moon is variable. The Earth-Moon tether tip would spiral upward in latitude, and when the Moon was closer, the slack would be taken up by drag forces within the atmosphere. How about the problem of pulling the Moon into the Earth? Well, maybe over a very long time. However, a counterbalancing tether, hanging outward from the Moon on its far side, would seem to take care of that problem. An Earth-Moon tether would be vastly more massive than a terrestrial space elevator. For one thing, the distance is much greater. For another, over much of that distance (past L1 toward the Earth), the forces of gravity won't be significantly counterbalanced by sub-orbital centrifugal forces. A space elevator's strongest point has to be at its center of mass in GEO. The Earth-Moon tether's problem, not long after the growth of it has touched down on the surface of the Moon, is in anchoring it strongly enough to the Moon. -michael turner [EMAIL PROTECTED] - Original Message - From: Mark Schnitzius [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, November 20, 2003 11:23 AM Subject: RE: Nanotube cable will connect Earth and Luna Obligatory quote from It's a Wonderful Life: George Bailey: What do you want, Mary? Do you want the moon? If you want it, I'll throw a lasso around it and pull it down for you. Hey! That's a pretty good idea! I'll give you the moon, Mary. Mary: I'll take it! Then what? George Bailey: Well, then you can swallow it, and it'll all dissolve
RE: Nanotube cable will connect Earth and Luna
Obligatory quote from It's a Wonderful Life: George Bailey: What do you want, Mary? Do you want the moon? If you want it, I'll throw a lasso around it and pull it down for you. Hey! That's a pretty good idea! I'll give you the moon, Mary. Mary: I'll take it! Then what? George Bailey: Well, then you can swallow it, and it'll all dissolve see, and the moonbeams would shoot out of your fingers and your toes and the ends of your hair... am I talking too much? Seriously, you could put a terminal at the Earth- moon L1 Lagrange point, but that's closer to the moon than it is to Earth. The pole idea might work. It wouldn't come close to crossing paths with any space-elevators that way too. I'm sure this crazy idea will fizzle for some other practical reason, though. To be replaced by something even crazier, no doubt. --Mark --- [EMAIL PROTECTED] wrote: Has anyone heard of this idea before? How would it work? The Moon doesnt revolve around the Earth at the same rate the Earth rotates, so how could such a cable be attached? (Through some sort of swiveling mechanism at the north or south poles, perhaps?) Would there be a danger of this cable getting tangled up with some Space Elevator cables that may have previously been built between the Earths Equator and synchronous orbit? If the cables got tangled, could they pull the Earth and Moon into each other? :-) John Sheff Cambridge, MA 02139 [EMAIL PROTECTED] -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of LARRY KLAES Sent: Tuesday, November 18, 2003 9:59 AM To: setipublic Cc: BioAstro; europa Subject: Nanotube cable will connect Earth and Luna NANOTUBE CABLE WILL CONNECT THE EARTH AND THE MOON Andrew Yee [EMAIL PROTECTED] InformNauka (Informscience) Agency Moscow, Russia Contact: A.N. Redkin or L.V. Maliarevich Institute of Problems of Microelectronics Technology and Extra Pure Materials Russian Academy of Sciences Chernogolovka, Moscow Region + 7 (095)962-80-74, + 7 (095)962-80-47 [EMAIL PROTECTED] 14.11.2003 THE NANOTUBE CABLE WILL CONNECT THE EARTH AND THE MOON Researchers from the Institute of Problems of Microelectronics Technology and Extra Pure Materials (Russian Academy of Sciences) have designed and tested a new device for production of a new promising material -- nanotubes. The researchers believe that it is exactly the material a transport cable can be produced of to connect the Moon and the Earth. Back at the beginning of the last century, the idea was born to build a transport cable between the Earth and the Moon to deliver goods from our planet to the Moon. Until recently, there has been no material enabling to make this idea a reality. Polymers would not stand cosmic radiation, and the steel cable would have enormous weight. The most durable material as of today -- Spectra 1000 -- would allow to produce a cable of only 315 kilometers long, as the longer cable is simply unable to bear its own weight. Carbonic nanotubes would very well suit the role of a structural material for such a cable. According to the researchers' estimates, a lightweight cable of required length can be produced from this material, the cable being 50 times stronger than the current most durable materials. The problem is that the researchers have not learned yet to produce high quality nanotubes in large quantities: that is either too expensive or feasible only in the laboratory environment. Therefore, this material is still pretty exotic, its price varying from $60 through $100 per gram. The scientists from Chernogolovka have designed a device that allows to produce pretty large amounts of high quality nanotubes. The device is based on a rather simple scheme: spirit, glycerin or their mixture gets from a specially cooled chamber into the zone of graphite heater bar, where the temperature reaches 1000-2000 degrees C. That results in ultraspeed heating and substance combustion. The products precipitate on a special carbonic glass bell covering the device, or they are removed outside together with vapors and gases, thus allowing to protect the product from various unnecessary impacts. Precipitations of such kind normally contain amorphous carbon, soot and various particles covered by a shell of carbon, as well as carbon fibre and nanotubes. However, in this particular case the researchers came across a surprise: the precipitations obtained in the device turned out to contain only nanotubes and carbon fibre. No other admixtures were found. It means that a laborious procedure is not required for rectification from unnecessary compoments. The fibres are 30-150 nanometers thick, and nanotubes are 20-50 nanometers thick, their length being several micrometers. The growth of nanotubes can be accelerated with the help of
Re: Nanotube cable will connect Earth and Luna
My take on this: the right kind of space elevator need not compete for orbital space with an Earth-Moon tether. A space elevator moving in the equatorial plane of the Moon could be an enabling technology for building the Earth-Moon tether, since it's probably the cheapest per pound way to get both to Earth-Moon L1 and to the surface of the Moon. It makes sense to think more in terms of how they might be complementary than competing. Designs I've seen so far for space elevators assume they are tethered to the Earth, and have an equatorial orbit for their center of mass. However, geosynchronous orbits don't have to be equatorial orbits. The Earth is tilted with respect to the Earth-Moon orbital plane, so a space elevator tethered to the Earth would either have to pendulum, or the tip of it would have to travel north and south through the atmosphere, making a round trip every 24 hours. A space elevator ground floor that travels thousands of miles a day is still moving slowly enough for a jet plane, and maybe a helicopter, to reach it, a small added cost. A pendulum approach might not work -- anchoring it might be too hard, and might introduce angles that conflict with an Earth-Moon tether. I don't this means we shouldn't do an anchored elevator, starting with equatorial orbit. Just that it should be designed so that it can be unhooked and moved to an Earth-Moon orbital plane later with relatively little trouble. Having a space elevator in the Earth-Moon equatorial plane is the first approximation to reducing the chance of an Earth-Moon tether and the space elevator ribbon crossing. aking the elevator ground floor mobile rather than fixed further reduces the intersection space. A second approximation might be to attach the Moon end of the Earth-Moon tether to one of the Moon's poles. This introduces a small angle. Finally, there's the issue of whether the Earth-Moon tether can be attached to the Earth, or whether it should just dangle outside the atmosphere. If the tip of the Earth-Moon tether is near the equator, there's a relative speed of about 1000 miles per hour. Consider, however, that once you're in an aerodynamic regime of any kind, all the rules change. As you get further into the atmosphere, you can use relative speed for aerodynamic lift, and rudders can steer the tether away from the equator, moving the tip into higher latitudes where the relative speed is much slower. The problems of attachment appear at the poles -- a relative tether-tip/atmosphere velocity that might become sub-aerodynamic. However, near those speeds, conventional aircraft could rendezvous with the tip, an attachment to the Earth would be unnecessary. One could imagine a standard cargo freight plane hovering over a landing pad at near stall speeds, then just touching down -- you wouldn't need something like an aircraft carrier dangling out there. The Earth-Moon's Earthside tether tip problems are further favored by being in an aerodynamic regime, because, unlike the space elevator's center of mass, the distance to the Moon is variable. The Earth-Moon tether tip would spiral upward in latitude, and when the Moon was closer, the slack would be taken up by drag forces within the atmosphere. How about the problem of pulling the Moon into the Earth? Well, maybe over a very long time. However, a counterbalancing tether, hanging outward from the Moon on its far side, would seem to take care of that problem. An Earth-Moon tether would be vastly more massive than a terrestrial space elevator. For one thing, the distance is much greater. For another, over much of that distance (past L1 toward the Earth), the forces of gravity won't be significantly counterbalanced by sub-orbital centrifugal forces. A space elevator's strongest point has to be at its center of mass in GEO. The Earth-Moon tether's problem, not long after the growth of it has touched down on the surface of the Moon, is in anchoring it strongly enough to the Moon. -michael turner [EMAIL PROTECTED] - Original Message - From: Mark Schnitzius [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, November 20, 2003 11:23 AM Subject: RE: Nanotube cable will connect Earth and Luna Obligatory quote from It's a Wonderful Life: George Bailey: What do you want, Mary? Do you want the moon? If you want it, I'll throw a lasso around it and pull it down for you. Hey! That's a pretty good idea! I'll give you the moon, Mary. Mary: I'll take it! Then what? George Bailey: Well, then you can swallow it, and it'll all dissolve see, and the moonbeams would shoot out of your fingers and your toes and the ends of your hair... am I talking too much? Seriously, you could put a terminal at the Earth- moon L1 Lagrange point, but that's closer to the moon than it is to Earth. The pole idea might work. It wouldn't come close to crossing paths with any space-elevators that way too. I'm sure this crazy idea will fizzle
Re: Nanotube cable will connect Earth and Luna
An amusing afterthought to my last: You're flying from Tokyo to London, over the North Pole. The pilot announces a rendezvous with the Earth-Moon tether tip. The plane touches down on the landing pad there. Some people get off, others get on. A passenger takes the seat next to you. He looks very tired. He pulls something out of his pocket. Want to hold a moon rock? he asks. I've also got a chunk of a captured asteroid And you act bored. Because that's SO two years ago. -michael turner [EMAIL PROTECTED] == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: Nanotube cable will connect Earth and Luna
, a counterbalancing tether, hanging outward from the Moon on its far side, would seem to take care of that problem. An Earth-Moon tether would be vastly more massive than a terrestrial space elevator. For one thing, the distance is much greater. For another, over much of that distance (past L1 toward the Earth), the forces of gravity won't be significantly counterbalanced by sub-orbital centrifugal forces. A space elevator's strongest point has to be at its center of mass in GEO. The Earth-Moon tether's problem, not long after the growth of it has touched down on the surface of the Moon, is in anchoring it strongly enough to the Moon. -michael turner [EMAIL PROTECTED] - Original Message - From: Mark Schnitzius [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, November 20, 2003 11:23 AM Subject: RE: Nanotube cable will connect Earth and Luna Obligatory quote from It's a Wonderful Life: George Bailey: What do you want, Mary? Do you want the moon? If you want it, I'll throw a lasso around it and pull it down for you. Hey! That's a pretty good idea! I'll give you the moon, Mary. Mary: I'll take it! Then what? George Bailey: Well, then you can swallow it, and it'll all dissolve see, and the moonbeams would shoot out of your fingers and your toes and the ends of your hair... am I talking too much? Seriously, you could put a terminal at the Earth- moon L1 Lagrange point, but that's closer to the moon than it is to Earth. The pole idea might work. It wouldn't come close to crossing paths with any space-elevators that way too. I'm sure this crazy idea will fizzle for some other practical reason, though. To be replaced by something even crazier, no doubt. --Mark --- [EMAIL PROTECTED] wrote: Has anyone heard of this idea before? How would it work? The Moon doesn't revolve around the Earth at the same rate the Earth rotates, so how could such a cable be attached? (Through some sort of swiveling mechanism at the north or south poles, perhaps?) Would there be a danger of this cable getting tangled up with some Space Elevator cables that may have previously been built between the Earth's Equator and synchronous orbit? If the cables got tangled, could they pull the Earth and Moon into each other? :-) John Sheff Cambridge, MA 02139 [EMAIL PROTECTED] -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of LARRY KLAES Sent: Tuesday, November 18, 2003 9:59 AM To: setipublic Cc: BioAstro; europa Subject: Nanotube cable will connect Earth and Luna NANOTUBE CABLE WILL CONNECT THE EARTH AND THE MOON Andrew Yee [EMAIL PROTECTED] InformNauka (Informscience) Agency Moscow, Russia Contact: A.N. Redkin or L.V. Maliarevich Institute of Problems of Microelectronics Technology and Extra Pure Materials Russian Academy of Sciences Chernogolovka, Moscow Region + 7 (095)962-80-74, + 7 (095)962-80-47 [EMAIL PROTECTED] 14.11.2003 THE NANOTUBE CABLE WILL CONNECT THE EARTH AND THE MOON Researchers from the Institute of Problems of Microelectronics Technology and Extra Pure Materials (Russian Academy of Sciences) have designed and tested a new device for production of a new promising material -- nanotubes. The researchers believe that it is exactly the material a transport cable can be produced of to connect the Moon and the Earth. Back at the beginning of the last century, the idea was born to build a transport cable between the Earth and the Moon to deliver goods from our planet to the Moon. Until recently, there has been no material enabling to make this idea a reality. Polymers would not stand cosmic radiation, and the steel cable would have enormous weight. The most durable material as of today -- Spectra 1000 -- would allow to produce a cable of only 315 kilometers long, as the longer cable is simply unable to bear its own weight. Carbonic nanotubes would very well suit the role of a structural material for such a cable. According to the researchers' estimates, a lightweight cable of required length can be produced from this material, the cable being 50 times stronger than the current most durable materials. The problem is that the researchers have not learned yet to produce high quality nanotubes in large quantities: that is either too expensive or feasible only in the laboratory environment. Therefore, this material is still pretty exotic, its price varying from $60 through $100 per gram. The scientists from Chernogolovka have designed a device that allows to produce pretty large amounts of high quality nanotubes. The device is based on a rather simple scheme: spirit, glycerin or their mixture gets from a specially cooled chamber into the zone of graphite heater bar
Re: Nanotube cable will connect Earth and Luna
e lapsing into (Bsevere doubt. At this point, the real problems will come from (Bvery unexpected directions. (B (B-michael turner (B[EMAIL PROTECTED] (B (B (B Joe L. (B (B On Wed, 2003-11-19 at 21:53, Michael Turner wrote: (B My take on this: the right kind of space elevator need not compete for (B orbital space with an Earth-Moon tether. A space elevator moving in the (B equatorial plane of the Moon could be an enabling technology for (Bbuilding (B the Earth-Moon tether, since it's probably the cheapest per pound way to (Bget (B both to Earth-Moon L1 and to the surface of the Moon. It makes sense to (B think more in terms of how they might be complementary than competing. (B (B Designs I've seen so far for space elevators assume they are tethered to (Bthe (B Earth, and have an equatorial orbit for their center of mass. However, (B geosynchronous orbits don't have to be equatorial orbits. The Earth is (B tilted with respect to the Earth-Moon orbital plane, so a space elevator (B tethered to the Earth would either have to pendulum, or the tip of it (Bwould (B have to travel north and south through the atmosphere, making a round (Btrip (B every 24 hours. (B (B A space elevator "ground floor" that travels thousands of miles a day is (B still moving slowly enough for a jet plane, and maybe a helicopter, to r (Beach (B it, a small added cost. A pendulum approach might not work -- anchoring (Bit (B might be too hard, and might introduce angles that conflict with an (B Earth-Moon tether. I don't this means we shouldn't do an anchored (Belevator, (B starting with equatorial orbit. Just that it should be designed so that (Bit (B can be unhooked and moved to an Earth-Moon orbital plane later with (B relatively little trouble. (B (B Having a space elevator in the Earth-Moon equatorial plane is the first (B approximation to reducing the chance of an Earth-Moon tether and the (Bspace (B elevator ribbon crossing. aking the elevator "ground floor" mobile (Brather (B than fixed further reduces the intersection space. (B (B A second approximation might be to attach the Moon end of the Earth-Moon (B tether to one of the Moon's poles. This introduces a small angle. (B (B Finally, there's the issue of whether the Earth-Moon tether can be (Battached (B to the Earth, or whether it should just dangle outside the atmosphere. (BIf (B the tip of the Earth-Moon tether is near the equator, there's a relative (B speed of about 1000 miles per hour. Consider, however, that once you're (Bin (B an aerodynamic regime of any kind, all the rules change. As you get (Bfurther (B into the atmosphere, you can use relative speed for aerodynamic lift, (Band (B rudders can steer the tether away from the equator, moving the tip into (B higher latitudes where the relative speed is much slower. The problems (Bof (B attachment appear at the poles -- a relative tether-tip/atmosphere (Bvelocity (B that might become sub-aerodynamic. However, near those speeds, (Bconventional (B aircraft could rendezvous with the tip, an attachment to the Earth would (Bbe (B unnecessary. One could imagine a standard cargo freight plane hovering (Bover (B a landing pad at near stall speeds, then just touching down -- you (Bwouldn't (B need something like an aircraft carrier dangling out there. (B (B The Earth-Moon's Earthside tether tip problems are further favored by (Bbeing (B in an aerodynamic regime, because, unlike the space elevator's center of (B mass, the distance to the Moon is variable. The Earth-Moon tether tip (Bwould (B spiral upward in latitude, and when the Moon was closer, the slack would (Bbe (B taken up by drag forces within the atmosphere. (B (B How about the problem of pulling the Moon into the Earth? Well, maybe (Bover (B a very long time. However, a counterbalancing tether, hanging outward (Bfrom (B the Moon on its far side, would seem to take care of that problem. (B (B An Earth-Moon tether would be vastly more massive than a terrestrial (Bspace (B elevator. For one thing, the distance is much greater. For another, (Bover (B much of that distance (past L1 toward the Earth), the forces of gravity (B won't be significantly counterbalanced by sub-orbital centrifugal (Bforces. A (B space elevator's strongest point has to be at its center of mass in GEO. (B The Earth-Moon tether's problem, not long after the growth of it has (Btouched (B down on the surface of the Moon, is in anchoring it strongly enough to (Bthe (B Moon. (B (B -michael turner (B [EMAIL PROTECTED] (B (B (B - Original Message - (B From: "Mark Schnitzius" [EMAIL PROTECTED] (B To: [EMAIL PROTECTED] (B Sent: Thursday, November 20, 2003 11:23 AM (B Subject: RE: Nanotube cable will connect Earth and Luna (B (B (B (B Obligatory quote from It
