Elevator up 30km to the Spaceport Hotel

update: There's a serious flaw in this idea that didn't occur to me when writing it...balloons lose their efficiency with altitude. So, yes, permanent platforms in the sky might me possible, and even useful (I like the idea of a floating yet anchored hotel), but they aren't going to be high enough to make space elevators any more practical. However, I'll leave the rest of this post as is.


For years, science fiction writers have been describing the concept of a space elevator. Rather than blasting off the face of the earth in a rocket, why not crawl up a cable all the way to space? It would certainly be much more efficient, though with somewhat less spectacular launches. The problem is, most experts say it will take a decade or more to build an actual space elevator.

Yes, it's a big problem to get a tether that stretches 100km into space, not the least of which is getting a material that can support it's own weight over that great a distance. Even then, the payloads are going to be small for quite some time. But, there just might be an easy short-term solution: balloons. Balloons can get 30km up fairly easily - and stay there for extended periods of time.

This might sound simplistic, but why don't we tie a whole bunch of high-altitude balloons onto a platform that is tethered to the ground? Why are we launching rockets from the ground when we could have a spaceport 30km up the gravity well? I'm not talking about launching a rocket after hoisting it up with a balloon. I'm talking about having a big platform, 30km up, regularly serviced by multiple elevators running up and down tethers. I'm talking about a high-altitude tourist hotel. If the proposed Aeroscraft will be capable of lifting 500 tons of material. What's to stop an absolutely massive structure supporting orders of magnitude more?

Imagine, if you will, a very large circular structure, something like the donut space stations of science fiction, with a central launch platform for rockets or, eventually, a tether all the way into space. Around the outside are hotel rooms for tourists; above them, hundreds of large balloons. So many balloons that they can be individually replaced as needed without any significant effect. Below, multiple tethers to the earth with elevators running up and down them constantly.

It would be a structure low enough down such that high-strength tethers could be used; not flimsy ribbons of carbon nano-tubes that can barely hold their own weight. I'm talking thick, heavy cables that tons of material can be hoisted up and down. I'm talking lots of thick cables capable of holding the spaceport where it is, no matter what the wind brings. It would be a structure high enough that it would be practically useful; a rock-solid spaceport securely suspended above all the nasty thick atmosphere and weather. It would be a place where it's easy to launch small rockets into space, where a 70km long space-tether might just stand a chance of working.

Why does the space-elevator concept have to go from the ground up to space in one go? We could easily break off the lower 30km segment, where most of the problems with wind exist, just by floating a platform with balloons.


Anonymous said...

Even then, the payloads are going to be small for quite some time.

Perhaps - we're aiming for a 20 ton GVW, 14 tons payload. The key is throughput; our goal is to have seven vehicles at a time on the ribbon, average travel time is seven days.

What's to stop an absolutely massive structure supporting orders of magnitude more?

Cost would be a big obstacle. It's going to cost a lot just to maintain that platform; probably more than the savings you would gain from the altitude boost.

Brian Dunbar said...

That was my comment above - I meant to put my sig at the bottom, sorry.

Brian Dunbar