Comments on: Paper Critiques Space Elevator and Scientists Overstate Their Case http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html Chronicling and Commenting on Human Progress Thu, 28 Aug 2008 16:15:34 +0000 http://wordpress.org/?v=2.2 By: Steve H http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-34601 Steve H Fri, 07 Mar 2008 05:45:03 +0000 http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-34601 Just a little doomsday thought here: IF one were to create a carbon ribbon through the ionosphere, there is a possibility that this would provide a short-circuit path to ground. Discharging the ionosphere would destroy the Earth's protection from solar wind and would probably make the planet uninhabitable very quickly. Most likely, if this short-circuit did in fact form, the ribbon would burn out quickly. But the potential to create an ionized plasma along the path of the ribbon exists. The result would be the mother of all lightning strikes. Even if the cable were an insulator such as Kevlar any contamination such as carbon or moisture would make it much more conductive than our atmosphere. Let's just say it would be a REALLY bad idea to try this on December 21, 2012. For safety, any attempt to build this thing should place an electrical meter at the end of the ribbon. If high voltage potentials are read, the project should be aborted while the line is still very far from ground. Just a little doomsday thought here:

IF one were to create a carbon ribbon through the ionosphere, there is a possibility that this would provide a short-circuit path to ground.

Discharging the ionosphere would destroy the Earth’s protection from solar wind and would probably make the planet uninhabitable very quickly.

Most likely, if this short-circuit did in fact form, the ribbon would burn out quickly. But the potential to create an ionized plasma along the path of the ribbon exists. The result would be the mother of all lightning strikes.

Even if the cable were an insulator such as Kevlar any contamination such as carbon or moisture would make it much more conductive than our atmosphere.

Let’s just say it would be a REALLY bad idea to try this on December 21, 2012.

For safety, any attempt to build this thing should place an electrical meter at the end of the ribbon. If high voltage potentials are read, the project should be aborted while the line is still very far from ground.

]]> By: Gunjan http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-33662 Gunjan Thu, 18 Oct 2007 07:31:24 +0000 http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-33662 I think one point everyone seemed to have missed that will solve lot of problems is that the last 100 miles of the ribbon that would interact with storms,weather, atmosphere etc. need not be made of nanotubes at all. It could be made of kevlar, nylon and lots of other more traditional materials. Note that the lower part of the cable will have the minimum load on it. Also the ribbon can be planned on being put into a storm quite zone. Here is a good online study from NIAC/NASA to read on this topic which points out solutions to some of the problems: http://www.isr.us/Downloads/niac_pdf/contents.html I think one point everyone seemed to have missed that will solve lot of problems is that the last 100 miles of the ribbon that would interact with storms,weather, atmosphere etc. need not be made of nanotubes at all. It could be made of kevlar, nylon and lots of other more traditional materials.

Note that the lower part of the cable will have the minimum load on it.

Also the ribbon can be planned on being put into a storm quite zone.

Here is a good online study from NIAC/NASA to read on this topic which points out solutions to some of the problems:

http://www.isr.us/Downloads/niac_pdf/contents.html

]]> By: Bruce http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1058 Bruce Sat, 27 May 2006 15:23:46 +0000 http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1058 Great to have you back, Anthony - and with a very good article. I commented recently on the Discover article on the radiation threat and had read the piece on nanotube defects and skimmed the technical article. There is still much that is unknown about CNT's but with so many applications from high-speed computer circuits to strong/light weight "whatever," I'm sure the material issues will get plenty of attention in the next few years. -Bruce Great to have you back, Anthony - and with a very good article. I commented recently on the Discover article on the radiation threat and had read the piece on nanotube defects and skimmed the technical article. There is still much that is unknown about CNT’s but with so many applications from high-speed computer circuits to strong/light weight “whatever,” I’m sure the material issues will get plenty of attention in the next few years.

-Bruce

]]> By: Anthony Kendall http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1019 Anthony Kendall Fri, 26 May 2006 03:18:54 +0000 http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1019 Tom, Good point about the fact that ropes are not as strong as single molecules, though I don't know the latest science on what strengths materials scientists think that they will be able to achieve. I don't think that it would be a good idea to allow the nanotubes to be conducting, so I think the chirality should be chosen to make the nanotubes insulating. A nanotube ribbon would be one hell of a grounding conductor between the ionosphere and the Earth. Tom,
Good point about the fact that ropes are not as strong as single molecules, though I don’t know the latest science on what strengths materials scientists think that they will be able to achieve.

I don’t think that it would be a good idea to allow the nanotubes to be conducting, so I think the chirality should be chosen to make the nanotubes insulating. A nanotube ribbon would be one hell of a grounding conductor between the ionosphere and the Earth.

]]> By: Tom http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1015 Tom Thu, 25 May 2006 20:47:00 +0000 http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1015 As the world's one-greatest purveyor of nanotube physical properties *wink* (http://www.pa.msu.edu/cmp/csc/ntproperties/) I can say that the 30GPa tensile strength estimate is pretty good for any kind of nanotube "rope", i.e. not one continuous molecule (100GPa). His one long but defective nanotube must equate to that of a rope, essentially. That is unless my data is really out of date and they can make long ropes or bundles above 30GPa tensile strength that I am not aware of. Anyway, if you had one long molecule that was getting all sorts of damage done to it, 30GPa is not an unreasonable conclusion. So, I don't know. This doesn't mean that it's impossible because nanotubes are being improved upon at such a fast rate that other technologies might make it possible.. particularly the ability to vapor-deposit coatings on the outside. What I haven't heard yet is how the nanotubes will be organized chirally... which makes a big difference in terms of electric conductivity. If they make it conductive, then one could send signals / power up and down the elevator, which could power the cabin or whatever. But, this thing is going to be the biggest tree on the golf course when it comes to weather since it's going to be poking through the clouds. Do you know how this issue might be overcome? As the world’s one-greatest purveyor of nanotube physical properties *wink* (http://www.pa.msu.edu/cmp/csc/ntproperties/) I can say that the 30GPa tensile strength estimate is pretty good for any kind of nanotube “rope”, i.e. not one continuous molecule (100GPa). His one long but defective nanotube must equate to that of a rope, essentially. That is unless my data is really out of date and they can make long ropes or bundles above 30GPa tensile strength that I am not aware of. Anyway, if you had one long molecule that was getting all sorts of damage done to it, 30GPa is not an unreasonable conclusion. So, I don’t know. This doesn’t mean that it’s impossible because nanotubes are being improved upon at such a fast rate that other technologies might make it possible.. particularly the ability to vapor-deposit coatings on the outside.

What I haven’t heard yet is how the nanotubes will be organized chirally… which makes a big difference in terms of electric conductivity. If they make it conductive, then one could send signals / power up and down the elevator, which could power the cabin or whatever. But, this thing is going to be the biggest tree on the golf course when it comes to weather since it’s going to be poking through the clouds. Do you know how this issue might be overcome?

]]> By: Anthony Kendall http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1010 Anthony Kendall Thu, 25 May 2006 17:37:27 +0000 http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1010 Thanks Paul! I hadn't intended to break out of my blogging vacation until next week, but that article was just something I felt I needed to address. Thanks Paul!

I hadn’t intended to break out of my blogging vacation until next week, but that article was just something I felt I needed to address.

]]> By: Paul Gilster http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1009 Paul Gilster Thu, 25 May 2006 17:26:40 +0000 http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-1009 This is exactly the kind of article we need more of. The annals of spaceflight are littered with prognostications gone wrong, including the famous New York Times editorial ridiculing Robert Goddard, and as you say, many people of sound scientific background have provided hopelessly wrong estimates about the future of various kinds of technology. The one thing we ought to know by now is that the future will surprise us, deeply and irrevocably, and part of the surprise will be the number of 'impossible' things that will eventually become all but routine. Great article, Anthony. This is exactly the kind of article we need more of. The annals of spaceflight are littered with prognostications gone wrong, including the famous New York Times editorial ridiculing Robert Goddard, and as you say, many people of sound scientific background have provided hopelessly wrong estimates about the future of various kinds of technology. The one thing we ought to know by now is that the future will surprise us, deeply and irrevocably, and part of the surprise will be the number of ‘impossible’ things that will eventually become all but routine. Great article, Anthony.

]]> By: The Space Elevator Blog http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-997 The Space Elevator Blog Thu, 25 May 2006 05:03:04 +0000 http://www.anthonares.net/2006/05/paper-critiques-space-elevator-and-scientists-overstate-their-case.html#comment-997 <strong>Paper Critiques Space Elevator and Scientists Overstate Their Case...</strong> One of my favorite websites is Anthonares.  The current essay responds to Nicola Pugno’s article claiming that Space Elevator’s are impossible with today’s technology (including carbon nanotubes).  The author, Anthony Kendall, is n... Paper Critiques Space Elevator and Scientists Overstate Their Case…

One of my favorite websites is Anthonares.  The current essay responds to Nicola Pugno’s article claiming that Space Elevator’s are impossible with today’s technology (including carbon nanotubes).  The author, Anthony Kendall, is n…

]]>