Talk:Space elevator

Unclear

"A newly discovered type of carbon nanotube called the colossal carbon tube may be strong and light enough to support a space elevator. Its tensile strength is only 6.9 GPa, but its density is only .116 g/cm3, making its specific strength sufficient for a space elevator. In addition, it has been fabricated in lengths on the scale of centimeters, a headstart on the thousands of kilometers needed for a space elevator.[38]" —Preceding unsigned comment added by Cmiych (talk • contribs) 16:58, 12 June 2009 (UTC)

In general, the entire article seems unclear and confusing, at least in terms of explaining the technical feasability or lack of such. The language is messy, people have edited the article without reading it properly themselves, and it has citation needititis. The entire Cable section is mostly suitable for confusion, especially if the reader has troubled himself with reading other sections, which seems to contradict the parts that are not themselves self-contradictory. In the section Powering climbers, there is an additionally confusing sentence that I cannot make sense of: "The fuel cell used also for the electric vehicle is expected to be used to the climbers of each ton." --anon 84.215.1.3 (talk) 23:59, 4 January 2010 (UTC)

Certainly, various people's sentences mix, and it doesn't understand well. In the section Powering climbers, The fuel cell that I had written was edited. Azure777 (talk) 12:20, 5 January 2010 (UTC)

Math

There's a nice page that does some quantitative calculations [1]. It would be great if his math could be checked and some information included in this article, which in its current form is pretty lite on science. —Preceding unsigned comment added by 24.16.88.14 (talk) 04:54, 18 August 2009 (UTC)

Space elevators on Mars or the Earth's Moon

If a space elevator on Mars can be much shorter than an Earth elevator, due to lower gravity, why would an elevator on the Earth's moon be very much longer. The Moon has even lower gravity, so the elevator should be even shorter than a Martian one. This discrepancy should be explained.JohnC (talk) 20:03, 25 August 2009 (UTC)

It's because the moon only spins once a month, whereas Mars spins every 26 hours or so.- (User) Wolfkeeper (Talk) 20:24, 25 August 2009 (UTC)

Looks like we are going to have an edit war. An anonymous contributor keeps adding a statement of his opinion that a Lunar Space Elevator is unrealistic. The Moon's geosynchronous orbit may be about the same distance as the Earth but that is only a cost issue. The Moon's rotation is tidal locked to the Earth so any space elevator built on the far side will not hit the Earth. Also as the section on Extraterrestrial elevators says the Lunar elevator will probably use one of the Lagrangian points, making it shorter. Andrew Swallow (talk) 04:53, 3 November 2009 (UTC)

Nah, he's got no references. He's wrong anyway of course: lunar space elevator.- (User) Wolfkeeper (Talk) 05:57, 3 November 2009 (UTC)

For missing citation in introduction

Pugno M, 2007, The role of defects in the design of space elevator cable: From nanotube to megatube, in Acta Materialia 55 (Elsevier) pp. 5269-5279 gives required strength to weight ratios of space elevator cable, theoretical s:w of carbon nanotube exceeding this, and actual s:w ratio of this material in laboratory tests /still/ exceeding requirements, even allowing for weakness due to the natural rate of defects in manufacture of carbon nantotube. —Preceding unsigned comment added by 129.96.121.117 (talk) 10:16, 10 September 2009 (UTC)

Dynamics of tethered satellite motion and control

The article seems to be missing a section on the dynamics of tethered satellites such as this would be. The equations of motion of a tethered satellite are considered to be non-linear differential equations with tendencies towards chaotic behavior. Theoretical analysis suggests that this can be controlled by varying the tension of the tether although the scale of the space elevator may require a different approach (http://www.springerlink.com/content/g7327314v627wm84/fulltext.pdf) and others. It doesn't seem consistent with the idea presented in the article that the tether would just point straight upwards and naturally return to that position.

An object moving up or down the space elevator would not change angular velocity as a simple consequence of is height change as the article seems to suggest. It would need to accelerated or decelerated with additional challenges for the dynamics of the system. (QuietJohn (talk) 02:22, 10 January 2010 (UTC))

But it would change angular momentum, and that's where problems arise.96.54.53.165 (talk) 01:40, 13 January 2010 (UTC)