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    <title><![CDATA[Discussion on Going up? Take an elevator ride to space ]]></title>
    <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427]]></link>
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    <lastBuildDate>2013-05-22T23:14:56-07:00</lastBuildDate>
             

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        <title><![CDATA[Good God]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-66514]]></link>
        <description><![CDATA[Where can I get some of the stuff you're smoking? Get back to your bong, hippie.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-66514]]></guid>
        <dc:creator><![CDATA[ddferrari]]></dc:creator>
        <pubDate>Tue, 20 Mar 2012 11:38:59 -0700</pubDate>
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        <title><![CDATA[Didn't bother to read your post...]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-66490]]></link>
        <description><![CDATA[but I gave it a big &quot;thumbs down&quot; for being longer than the article itself. Reel it in, Bob.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-66490]]></guid>
        <dc:creator><![CDATA[ddferrari]]></dc:creator>
        <pubDate>Tue, 20 Mar 2012 11:36:47 -0700</pubDate>
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        <title><![CDATA[Rubbish learn some physics]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-65034]]></link>
        <description><![CDATA[Potential energy is added to the elevator cab from energy sources in orbit or on the ground, no PE is drawn from the elevator itself.  This is the point of the elevator, the cab does not need to carry its own energy source and can recover the PE required to climb out of the gravity well when it falls via regenerative braking.  Rockets and jets have to carry their own energy sources as well as a reaction mass.  Most of a rocket is reaction mass/fuel and the hardware to manage it.  In fact if more mass is imported from space than is exported the elevator transport would be a net energy generator.While we are fanatsizing, laminate supercondutor on the surface of the elevator and plasma coat that with reflective material.  The resulting structure should be effectively immune to thermal shock from laser or other sources and provide a handy way to deliver power to the ground.Locating the elevator in a remote location is daft.  That is like locating a major seaport, airport, rail and road terminus (same thing really) in a remote location.  The only results are to pollute the remote location to inconvenience all the staff and users who have to relocate to the remote location and add to the construction cost.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-65034]]></guid>
        <dc:creator><![CDATA[Paul Kemp]]></dc:creator>
        <pubDate>Fri, 02 Mar 2012 12:42:30 -0800</pubDate>
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        <title><![CDATA[Floating Anchor is Fine]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64962]]></link>
        <description><![CDATA[Adding weight to the hold down floating anchor will be much easier than adding cable and counterweight to lift it up.  For example, a 100,000 km cable and its counterweight is about 75 times the mass that it can lift from the earth's surface.  You mention the pulls and pushes caused by the movement of the 'cabs'.  Putting on too heavy of a cab will actually pull the space elevator down.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64962]]></guid>
        <dc:creator><![CDATA[EmmettRedd]]></dc:creator>
        <pubDate>Thu, 01 Mar 2012 11:10:13 -0800</pubDate>
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        <title><![CDATA[Payback]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64927]]></link>
        <description><![CDATA[It's a question of payback. You have to look at the total cost of building and launching the rockets for a given amount of conclusion. You also look at the cost of building and operating the total cost of the elevator. The elevator will have a much longer time to payback than the rockets, but it will only have to be built once. The rockets are not reusable (currently). Payback time is close to 20 years in studies I have seen.currently, businesses want new construction to have a payback time of 14 years. So, it's not a business case yet, but the case is improving. Every year it gets closer to being economical.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64927]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 20:39:39 -0800</pubDate>
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        <title><![CDATA[Steel]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64926]]></link>
        <description><![CDATA[Speaking as an Engineer, yes, this material would enable a lot of things. But, don't expect steel to dissapear. Wood is after all still with us.Concrete gives excelent strength in compression. Concrete is weak in tension. Steel is strong in both tension and compression. Carbon nano tubes are strong in tension and weak in compression. Yes it will have uses, but the uses will be somewhat limited. Cost will also be a factor.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64926]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 20:34:15 -0800</pubDate>
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        <title><![CDATA[Debt Reality]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64925]]></link>
        <description><![CDATA[Blaming the US National Debt on one political party or another is just a cop out!When Clinton left office, the National Debt was around 8 Trillion Dollars. It was around 7 trillion when he entered office. When Bush left Office, the National Debt was 10 Trillion Dollars. It is now around 15 Trillion Dollars, that means that 1/3 of the total National Debt has been run up under the current President. But, The spending of the government is the domain of Congress. Most of the build up of Debt under Bush was in his last two years. That was under the Democrat dominated congress of Pelosi and Reid. This was also the makeup of congress during the first two years of the Obama Administration.However, no Congress since the beginning of the great depression has had the discipline to pay off the debt. That includes both Democrat and Republican congresses over more than 80 years.Sadly, the current memes in Washington is to just pass the problem on to later generations. That only works as long as you can still get people to buy the bonds. We are approaching the end of that road.As Van Johnson observed in 'The Pied Piper of Hamlin', &quot;For come what will or come what may, the day will come you have to pay...The Piper!&quot;That day will soon be here.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64925]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 20:29:04 -0800</pubDate>
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        <title><![CDATA[Forces]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64933]]></link>
        <description><![CDATA[The problem with the 'floating anchor' is that the cable requires tension to avoid resonance problems (like a flapping flag). There will be several hundred tons of upward pull on the ground end of the tether. It's be embarrassing to have your sea anchor go flying off into interplanetary space. There will also be the pulls and pushes caused by the movement of the 'cabs'.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64933]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 20:16:29 -0800</pubDate>
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        <title><![CDATA[You Don't Take It Down]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64924]]></link>
        <description><![CDATA[For a spinning tether, you don't 'take it down', you just cut it in half, and both halves go flying off into space. The timing of the cut will determine where they go. The pieces can be retrieved later for recycling. If you have the reaction mass available, you could also just push on the center and move the tether to any point desired.For practical use, the tether will need thrust units at both ends, and in the center. These are not simple machines.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64924]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 20:11:54 -0800</pubDate>
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        <title><![CDATA[Energy]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64942]]></link>
        <description><![CDATA[No, raising the loads requires energy. That is supplied by a large orbital power station. There is not loss or gain of momentum that is not included in the calculations. There is even an acceleration on the cable from the Earths magnetic field that will have to be taken into account.That is all taken care of in the overall totals.Long term, the total energy up and down will balance. If not, the planet would either be slowed down or sped up. But, it might take a million years to be able to measure it.by the way, the Moon is slowing down the Earth anyway. Earth is also speeding up the Moon too. Someday (in about 5 Billion Years) the Earth will fling the Moon off into space.Meanwhile, the Sun is slowly changing the earths orbital speed too. (Geological change is rapid in comparison to how fast the Solar Orbit is changing.)Space is complicated.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64942]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 20:07:08 -0800</pubDate>
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        <title><![CDATA[Not All Locations.]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64920]]></link>
        <description><![CDATA[Not all locations on the Equator are equal. There are two preferred locations because the Earth is not a perfect sphere.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64920]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 20:00:58 -0800</pubDate>
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        <title><![CDATA[Check it Out]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64932]]></link>
        <description><![CDATA[Yes, we did check it out years ago. The results were that it is a good idea, but that it isn't feasible yet. it is within the known strength of materials, but is too hard for us at the level of technology available then. Our ability is getting closer to what it would take, but it's still a project for the future. First go around it was considered not doable for a Century. The, not for a half century. Now, it seems to be something to consider seriously in around 20 years. I think that the time to seriously consider doing it will be in 10 to 15 years. Meanwhile, the research should consider. This report is someone who is pushing for the research.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64932]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 19:57:55 -0800</pubDate>
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    <item>
        <title><![CDATA[Money]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64923]]></link>
        <description><![CDATA[No, money is a way of counting things, and comparing their value. Thinking that we can spend an infinite amount of money wastes a lot of resources. Everything you or I do is trading some value (mostly our time and talents) for something someone else did. What we are doing is not making money something you don't have to worry about, it's really just changing the way we track it. (we have gone from valuable metals to paper and now to bits.) It doesn't change the reality of what we are tracking, however. If you want to say that it does, you are just making your money (and mine probably) become worthless.It doesn't matter if you want to take the money spent on arms and use it to buy food. That doesn't change the amount of food there is, it also doesn't change the value of the unused metal. It does though, deprive the metal workers now producing tanks of a means of supplying their families with what they need. Ever try to eat a tank? It isn't very nutritious.I do like the idea of settling space. I don't however delude myself that we can just spend without paying off or paying back the sources of the money.Yes, the resources expended in a small war would be enough to pay for a colony on the Moon with a population similar to that of Wyoming. But it would still be an expense that would ultimately have to be either paid, or have the sponsoring society harmed to that amount.Money may be 'imaginary', but it represents real work and real resources. Don't be misled. Every Cent must be accounted for, or you are harming someone.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64923]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 19:50:06 -0800</pubDate>
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        <title><![CDATA[Not So]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64931]]></link>
        <description><![CDATA[Starman35, this has been studied by physicsists and chemists as well as astronomers. At the ground, the tether would be a ribbon around a meter wide, and only a couple of millimeters thick, except for where the power and communications cables are installed. It would taper up in thickness to the station, then taper off after the station. If Carbon Nano tubes (pure) are used, it would be around 30 Meters across at the station. If Diamond were used, it would have to be thicker, around 150 Meters across at the station. If Tungston Steel were used, it would have to be around 2 Meters across at the ground end, and taper up to around 5 KM across at the station. There are ranges of size needed that are dependent on the tensile strength of the material used. Even spider silk has been considered. The problem there is that the strength of the silk requires water in the bonds. It would have to be encapsulated. Spider silk is about 10 X stronger than steel in tension. That's better than we get with current tether materials, but less than the carbon nano tubes are capable of.It probably won't be possible to build until after we already have colonies in space. It's much easier to build it in place and then lower it to the ground.So it is possible, will be profitable, but not in your lifetime. It's long range research at this point. But, research has spinoffs. There will be whole new industries in the next 20 years or so from this effort.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64931]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 19:35:41 -0800</pubDate>
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    <item>
        <title><![CDATA[The Engineer in Me.]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64890]]></link>
        <description><![CDATA[As one Engineer to another, this isn't an elevator cab which is either a cable suspended or a hydraulic lifted cab. The plan for a space elevator has always been to have several cables, with an electric current in conductors inside the cables creating an electric field, then using magnets in the cars to run up the cable as a linear motor. Presumably, the cars would draw power from other wires in the cable too.What I wonder about is the limiting of the car to 200 KPH. This would make sense in the atmosphere. Vibrations would be induced in the cables by winds. Once above the atmosphere, there is no reason to limit the cars speed. It could then accelerate up to any reasonable speed. It would of course have to decelerate at the top too. But, speeds of up to 5000 KPH would appear reasonable once you are more than say 150 KM above ground level. It would be a comfortable trip if you kept the acceleration down to around 12 M/S^2. Changeover would be uncomfortable, as the room would seem to flip from right side up to upside down, but a simple gimbals system would make that easier to take. A quick back of the envelope calculation would give a total trip time of only a few hours. Less than the time for a subsonic transatlantic trip.The thing would be a power hog. Existing conductors are not up to the task of the power levels that would be needed. You would probably want to power the system from both space and from the ground. The electrical coordination required would be quite interesting.The existing nano tube fiber systems are not near the strength required for the systems yet. Nano tube fibers to date are not very long. They are also quite flammable. Yes, they will cut steel or even titanium. No need to worry about the fictional terrorists cutting the cable with an aircraft. It would take a laser. But, the cable would burn very well.Current tether materials are more plastics with the carbon nano tubes embedded. This has the advantage of both binding the little things, and protecting them from the oxygen. This approach has yielded tethers of over a kilometer in length. But, the strength is only a little better than steel. Much work remains to be done on tether materials.The Space Elevator will need something that can be responsive to vibration dampeners in the atmosphere, resistant to impacts from orbital debris, as well as resistant to UV radiation and cosmic rays. It would also have to have better bonding of the carbon nano tubes into the matrix, and be able to increase the amount of nano tubes in the matrix. It's an interesting materials problem. Progress is being made though. The sort of material needed will be useful for many construction projects here on Earth too. It will be a wonderful tension member. It can provide great compression strengthening too by having a non compressible material inside a wrapping of this material. Tether wrapped concrete columns would enable mile high buildings to be much lighter. It would enable much longer bridge spans. It would also enable structures that are not currently possible.The biggest hurdle to developing the basic system is to be able to reliably produce the long strands of carbon nano tubes for inclusion in the matrix.The material for the power wiring is another fascinating area for consideration. a room temperature superconductor would be ideal. A material that doesn't super-conduct might be necessary, but I would want a material with lower resistance than copper wire.All of these details are why Aurthur C Clark said it would take 50 years after people stopped laughing before it was done. they stopped laughing 5 years ago.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64890]]></guid>
        <dc:creator><![CDATA[YetAnotherBob]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 19:14:13 -0800</pubDate>
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        <title><![CDATA[space elevator]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64913]]></link>
        <description><![CDATA[I only wish I would live long enough to take that elevator ride but before the elevator is built maybe we can span the oceans with nanotube arches that will carry cargo on trains powered with solar powered magnetic drive and ... International trade can become as efficient and fast as international communications has become. Oh the brave new world lay before us a paradise for the young to enjoy..No?]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64913]]></guid>
        <dc:creator><![CDATA[ltchaos]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 14:57:02 -0800</pubDate>
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        <title><![CDATA[Money?space]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64880]]></link>
        <description><![CDATA[I like this long view and the not war part now if we can just get everyone to cooperate.]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64880]]></guid>
        <dc:creator><![CDATA[ltchaos]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 14:28:09 -0800</pubDate>
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        <title><![CDATA[CREATVIE IDEA]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64898]]></link>
        <description><![CDATA[First of all if we did come up with a material that could handle this sort of thing, what would be the cost of building it in the first place? Second yes it is probably a lot cheaper then Rockets but might have to look at the cost of building it verses a rocket. But i like the idea and it would be fun to ride in one someday. Thinking of new an innovative idea means we are thinking outside the box, and that is how we move forward. ThanksJust an opinion]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64898]]></guid>
        <dc:creator><![CDATA[bookkeeper@...]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 11:54:12 -0800</pubDate>
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        <title><![CDATA[What if ......]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64878]]></link>
        <description><![CDATA[&quot;What if&quot; is the excuse for doing nothing.  What if I go out to get in my car and a tree falls on me?  I should not go out; I should stay inside.  What if there is a gas leak in my house and it explodes?  I should not stay inside; I should go out.  I'm so confused ... I am locked in a set of 'what if' tragedies and disasters .... Oh, there is no escape .... what to do, what to do .............]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64878]]></guid>
        <dc:creator><![CDATA[bmyers@...]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 07:25:56 -0800</pubDate>
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        <title><![CDATA[New Material - huge new opportunity]]></title>
        <link><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64874]]></link>
        <description><![CDATA[What people seem to miss is that if Graphite Nano-tubes become a reality it will totally revolutionise the construction industry. Steel will simply be a material of the past. There is plenty of carbon about so we would look at the end of the metal era and eneter a totally new era, probably of fusion of digital with strength (graphene has extraordinary electrical properties as well as enormous strength).]]></description>
        <guid><![CDATA[http://www.smartplanet.com/forum/discussions/1-9427-64874]]></guid>
        <dc:creator><![CDATA[lhesselgren]]></dc:creator>
        <pubDate>Wed, 29 Feb 2012 02:27:45 -0800</pubDate>
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