Check out the development of diamond cable http://www.cnn.com/2014/10/10/tech/innovation/space-elevator-nanotechnology/
On Sat, Jan 17, 2015 at 8:41 PM, <[email protected]> wrote: > In reply to Jed Rothwell's message of Sat, 17 Jan 2015 17:47:23 -0500: > Hi, > [snip] > ><[email protected]> wrote: > > > > > >> Actually what I had in mind was more something with just jet engines iso > >> rocket > >> engines, not something carried into the air on the back of a jet. > >> > > > >What is the typo "iso" supposed to be? Instead of? Inside of? > > > >Anyway, you need both. The jet engines no longer work at high altitudes. > >The piggyback method is used so that you can leave the jet engines behind > >when they become useless for lack of air. > > > > > > > >> Space elevators should never be built. Far too dangerous (read "Red > >> Mars"?) and > >> unstable (wind problems). > >> > > > >I read "Red Mars." That is an incorrect portrayal of the way a space > >elevator would work, at least in the first implementation for the next > >century or so. If you cut one at that ground it would simply drift up and > >away. If you cut one at the space station terminal, or halfway down, it > >would fall to earth with approximately as much force as a falling > >newspaper, according to Edwards and Westling ("The Space Elevator.") The > >cable is about as thick as a piece of paper and about a 20 cm wide at the > >widest point, as I recall. It is 200 layers each 1 micron thick (0.2 mm). > >This would support 20 tons: > > > >http://www.thespacereview.com/article/47/2 > > The weakness in this as near as I can tell is that the strength of the > ribbon is > only the same as that of individual nano-tubes if they can be attached to > one > another effectively and with the strength of the bond equal to the > strength of > individual tubes. Either that, or individual tubes need to be 35000 km > long. > > Furthermore, I get the impression from the article that the given strength > of > 300 GPa, is only calculated, not necessarily measured. > > However if the problem(s) can be overcome, then I take back my claim that > space-elevators would never be built. > > > > >Of course if there were a 20-ton climber on the cable below where you cut > >the cable, the climber would come crashing back to earth. > > This is actually the most likely scenario, because the tension on the cable > increases with altitude, so it is maximal at the top, and hence that is > also > where it is most likely to break. However a single climber would most > likely > crash in the ocean, and is unlikely to do any significant damage. > > > > >Wind is not a problem. The thing can stand up to far greater forces than > >that. The total exposed surface in the atmosphere is smaller than the face > >of a large building. > > I was thinking of resonance (think violin string, loaded with a climber). > If this turns out to be a real problem, then the whole project might end up > being very short lived. > > > > >- Jed > Regards, > > Robin van Spaandonk > > http://rvanspaa.freehostia.com/project.html > >
