What? No. Just… no.
Sigh. OK, here’s the short form: park an asteroid in Earth orbit, start unreeling a tether from it towards Earth. OK, fine so far… standard Space elevator stuff. But keep building it down until the bottom of the tether is in the atmosphere… and then hang a skyscraper from it.
Errrrmmmm… no.
For starters: materials science. The best stuff we can envision, graphene, *might* be just capable of making a tether that can support its own weight when hung from geostationary. With luck, we could get an elevator car to run up and down on it. But you know what weighs more than an elevator car? An entire friggen’ building.
Second: since the skyscraper is suspended from the cable above the ground, it’s free to wave about in the breeze. But that’s small taters, since the asteroid is not in a standard geostationary orbit, fixed over one spot over the equator. instead it’s on a 24-hour orbit, but highly inclined. Thus at one point in the day it’ll go as far north as New York City, and of course 12 hours later it’ll be just as far south of the equator. But you know what that means? it’s not just sedately wandering, it’s tear-assing across the sky like a jetliner. i can’t be bothered to figure out how fast it’ll be going when it crosses the equator, which is when it’ll be at its fastest, but I suspect it’ll be pushing Mach 1, And buildings kinda suck at that. It hangs down low enough that you have to design it so it doesn’t hit the terrain, so that means it’s a fantastic obstacle for jetliners. I further suspect that a cable 50,000 kilometers long won’t just stay pointed straight down, but might sway just a tad.
So, is this a serious proposal? It can’t possibly be. It’s a Neat Idea, safely sci-fi; a way for the design firm behind it to get some press. And press they got, unskeptical slobbery press akin to what Solar Roadways and Self Filling Water Bottles and Barack Obama got. I’ve got no problem with the designers… they label it as “speculative” and should take that to Hollywood and make some scratch. But the press needs to be smacked around some. At least some outlets bothered to contact someone who could tell ’em some debunkery.
One other notable flaw in the concept: the idea seem to be to build the major sections of the skyscraper *as* actual terrestrial skyscrapers, reaching kilometers into the sky. Then, they are attached to the bottom of the tether and hauled up. this may sound good… but it ain’t. The skyscrapers during construction would be, like every other tall building, under considerable *compression.* But when you grab ’em by the top floors and lift them up into the sky, they’re no longer in compression, but tension. These are essentially contradictory environments. Concrete is great from compressive loads; it sucks for tension. Graphene cables are great for tension; they’re no use at all in compression. These building would need to be built to handle *both,* and that’s the sort of requirement that makes engineers who are also trying to save weight – because, you know, they’re suspending this thing from 50,000 kilometers of bleeding-edge string – throw their hands up in disgust and decide to take up growing pot for a living.
