Slashdot Mirror
Space Elevators Going Up
MikShapi writes "CBC is running a new piece on the Space Elevator. Nothing dramatically new, as we're all still waiting for one of the many Carbon Nanotube research centers to announce they reached the famous 100GPa red line from page 10 of the NIAC Phase 2 Report, thus obtaining 'unobtainium' [pun intended], the material necessary to build the Elevator. The report predicts this will happen during the course of the next two years or so. It's then that the fun really starts - A REAL all-out space race, open to everyone with will and a national budget, winner probably getting to own space [read last paragraph]. In the meanwhile, we can all spread the word, discuss, debate and brainstorm every nook and cranny of the program here on Slashdot, and give Edwards a shoulder by giving the program every bit of mass-exposure we can."
Getting 100 GPa for carbon nanotubes composite is one thing. Getting 100 GPa on a 100000 kilometers carbon nanotube composite is another.
I'm more interested in the length of the nanotubes than in their strengh since increasing the strengh is quite easy (basically all we need is to increase the fraction of carbon nanotubes in the composite) compared to increasing the length of the composite.
Iraq: war to save the U
Warren Buffet often argues that since he is more productive than average, it's better for him to put his money to work than donate it to the needy. Once he dies, the argument goes, the money (a greater sum due to compounding) can be distributed. Take any discovery expedition - Columbus, Cortez, Polo - figure the aggregate value gained vs. the actual cost. This is the principle of investment.
...the 100 GPa number sounds ridiculous.
For context: the most common type of structural steel currently used has a yield strength of 350 Mpa. 100 GPa is 285 times stronger. And stronger isn't enough, it has to be dependable and resistant to cyclicle loading and fatigue, which isn't easy to quantify, especially under such unusual conditions.
To suggest that this can be achieved in a couple of years sounds silly to me, considering whatever material used would a lengthy term of testing and a proven track record before sinking billions of dollars into it.
Unless it breaks, it can't tip over. It's like hanging a yoyo from your finger. There's no way the string is going to tip over onto your hand.
I'm not the least bit concerned about the carbon nanotubules. I'm still trying to figure out how their going to ATTACH the damn thing. All buildings are essentially resting upon the Earth. This thing can't rest, it needs to be attached. For a cable this long, a "stupid hurricane" could set up a vibration is going to build to the point where the whole thing starts "walking" across Columbia.
Don't blame me, I didn't vote for either of them!