How a sci-fi dream could be built today


But before we get to that even more impossible-sounding idea, let’s stick with the basic science for a moment. If the people of your time are so used to Space Elevators that they seem as dull as the regular variety, it’s going to be because enough people of our time (your grandparents and great-grandparents) began to truly believe we could build such a thing.

And that’s tough, because the idea of a cable going straight up into the heavens does not make intuitive sense. Quite the opposite. To many of us, the Elevator sounds like a beanstalk from a fairy tale, or a Tower of Babel: some kind of vertigo-inducing folly, bound to come tumbling down from the heavens by the end of the story. We’ve seen enough monuments to human hubris to suspect that.

But if we think this, it’s because we forget something else that doesn’t make intuitive sense: The Earth is spinning, at the impressive speed of 1,000 miles per hour. This means a tether connected to a space station at the right distance (at least 60,000 miles up), with its center in geostationary orbit — that is, traveling above the Equator at 1,000 miles an hour, so the Earth seems to stand still — would be as solid as any cable in an elevator shaft.

That explanation still requires math. Here’s the analogy that clicked for me when I first wrote about Space Elevators 15 years ago, one that still seems to work for a lot of people new to the concept. Imagine yourself in your yard, spinning around as fast as you can with a tennis ball on the end of a piece of string. Would that string be taut? You betcha — so much so that an ant could easily climb from your hand to the ball. Well, the Earth is you, the counterweight space station is the ball, and the Space Elevator is the string. (The only difference is that the Earth never gets tired or dizzy.)

The Earth-Sputnik Elevator

We also have to clear our minds of traditional ideas about how you build something that tall. Russian scientist Konstantin Tsiolkovsky is sometimes credited as coming up with the Space Elevator concept in 1895. But in his highly speculative essays, Tsiolkovsky suggested building from the ground up — an orbital tower, basically — because he’d just seen the Eiffel Tower. That wouldn’t work; even with super-strong materials, the base of such a tower would need to be wider than Paris.

It wasn’t until 1960 that Soviet engineer Yuri Artsutanov came up with the basics of the idea we know today: You put a satellite in geostationary orbit, with a tether rolled up inside it like a tape measure. Then you extend the tether up into space and down towards the Earth’s equator at the same time, keeping a perfect balance between the two. Artsutanov had a nice turn of phrase; he called his proposal an “Earth-Sputnik-Earth” elevator and a “heavenly funicular.” Unfortunately, his work was published only in Pravda, the Soviet propaganda newspaper, not the big science journals, so the world beyond the Iron Curtain knew nothing about it.

Luckily, U.S. scientists came up with the idea independently anyway. In 1966, four American oceanographers proposed what they called a “Sky-Hook” that would “elongate satellites.” (Oceanographers seem to have a curious connection to the history of Space Elevators, which makes sense when you consider they deal with long cables that have to hang under their own weight.) But their proposed tether was too thin, making it an easy target for micro-meteorites. And famed space scientist Jerome Pearson didn’t even know about it when he too re-invented the Space Elevator in a 1975 paper. 

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