[jcfrei]

I don't really see the benefits of space elevators, to be honest. At an altitude of 100km the gravity is still virtually the same. And you still need a huge amount of fuel in order to put your rocket/plane into orbit. Unless you build an elevator with a height of 42'164km (geostationary orbit) - but that seems unrealistic to me.

[thedufer]

> Unless you build an elevator with a height of 42'164km (geostationary orbit) - but that seems unrealistic to me.

Actually, much of the point is to build one that is significantly taller than that. The idea is that, if the center of mass sits at geostationary orbit, the elevator doesn't actually have to hold itself up. Centripetal forces do the heavy lifting. Try the wikipedia link posted by gp - the first thing you'll see is a very clear diagram.

[ZenoArrow]

> "I don't really see the benefits of space elevators, to be honest. At an altitude of 100km the gravity is still virtually the same."

You would have made the first 100km of the journey more fuel efficient, is that not a good enough reason?

[jcfrei]

I think it's just prohibitively expensive at the moment. 100km (I think it would have to be a lot more anyway) is not much in terms of space exploration. And even then you will always use the majority of your fuel for acceleration towards and deceleration at your destination (however fuel needs for deceleration might be much lower if you can do some sort of atmospheric braking).

[imglorp]

There's a very real possibility that a conductive cable would generate tons of power which could be used by the climber plus surplus on the ground.

[david-given]

You have to build space elevators up to geostationary orbit (and beyond). That's the whole point; they don't work otherwise.