Space Ladder, alternative to space elevator

[impyre]

I've read quite a bit about alternate methods of getting to space.... space elevators, guns, etc. What about a space "ladder" as an alternative? Basically, put up a platform and structure at high altitude and hold it up with balloons, then tether that thing. Depending on how high you're able to get it, you could get into orbit relatively easily. You could launch small rocket-borne payloads up to one to two hundred kilograms in small reusable rockets. With this, the transit time could be pretty low and require somewhat less fuel. The only downside I can think of is that the payload limitation being so small would require everything to be built in orbit of much smaller parts. However, this could be offset somewhat by having vehicles that never need to reenter... like a shuttle that just hangs out up there. If you need to get back, use the reentry pods that were launched unmanned from the floating launchpad in the sky. If you need to get up there, just ride up the elevator, hope on a small rocket and rv with the station.

Thoughts?

[peadar1987]

Most of the delta-V expenditure for getting into orbit isn't getting up high, it's getting up to speed. The reason a space elevator works isn't primarily because the tip is high up per se, it's because it's a very long arm that magnifies the speed of rotation of the earth. You'd save a bit of delta-V launching from a balloon, for sure, but not a huge amount.

[lajoswinkler]

We've got mountains higher than 8 km, so we could launch from their tops. Thing is - expenses (money+energy) to haul the stuff up there is much higher than just stick boosters for getting out of troposphere. We don't need anything else because we don't live on Venus or Eve.

[Seret]

Depending on how high you're able to get it, you could get into orbit relatively easily.

You'd have to get pretty high to have much of an effect. Space elevators work because once you get up to c.40,000km altitude you've got enough velocity to be in orbit. The highest a balloon has ever gone looks like about 50km, so that's about 1/800th of what you need to attain orbital speeds.