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Space Elevator Challenge
MattSparkes writes "For the second year in a row, no team has won the $200,000 prize in the Space Elevator Challenge at the Wirefly X Prize Cup. Three teams were disqualified before the contest even started. Another competition at the event has been held up by confusion. Incredibly, it seems the organisers of the competition are not sure whether the ribbon used was 50 or 60 metres long, and whether any team completed the climb fast enough to win."
Can anyone enlighten me how that thing supposed to work?
See Wikipedia.
We fasten one end on ground and second end is fastened... where???
To an orbiting counterweight.
And what about Earth rotation?
Earth's rotation is what makes it work. Otherwise:
I still think that normal elevator - a-la tower - is much saner idea and can be achieved easier
Yeah, nobody ever thought of that idea. They're pursuing orbital tethers because they're all insane masochists.
A tower would be much more massive and would have to support its full weight. Tethering to an orbiting counterweight allows centrifugal effects to lighten the total load, since the Earth is rotating. You couldn't build one high enough to reach geosynchronous orbit, and thus whatever you brought to the top wouldn't be in a nice circular orbit when it got there; it would still need something like rocket thrust. With a tether, as soon as you get up to geosynchronous, you're automatically in a circular orbit. See the "compressive structure" entry on Wikipedia.