Reaching New Heights In Space Elevator Technology

I figure that by this point most people already know what a space elevator is, but I really love them so I’m going to talk about them anyway. For anyone who still doesn’t quite understand the concept, a space elevator is a cable (or theoretically a building, although this is almost certainly impossible) that stretches up from the ground far out past geostationary orbit until it’s center of mass is in geostationary orbit. It’s possible to get around this and have it end much closer to geostationary orbit if you include something very heavy at the end like the asteroid in Red Mars.

So the first thing to talk about is a space elevator on Earth. Geostationary orbit on Earth is 22,206 miles up, which is roughly 4,000 Mount Everests tall or roughly 9% of the way to the moon. This presents a problem as a thread of any material has a length at which it will be too heavy to support itself. Until recently Zylon the material which held the record for highest tensile strength had a “breaking length” of 238 miles, which is great but still roughly 22,000 miles too short. Luckily for the space elevator carbon nanotubes have come into production recently with their astounding breaking length of *drumroll please* 3,100 miles.

Again luckily for our friend the space elevator this problem has two solutions, one of which is applied automatically by the laws of physics. The first solution is that gravity gets weaker the farther you are from a planet which reduces the weight and increases the breaking length of a material. The second is that in the same way you can make a building wider at the base to build taller you can make a cable wider at the top to support more weight. Applying both of these factors you end up with a cable that is 1.3 times wider at the top than at the bottom.

So that seems easy. Time to launch our space elevator. Sadly, it isn’t that simple currently the cost of those carbon nanotubes could go into the trillions and it just isn’t feasible, but with all of the research and money currently being invested into them, a space elevator could definitely be possible within the next 50-100 years. As a closing note for those worried about the effect of a falling space elevator, it’s in orbit. If it were to be cut most pieces of it would fall/rise (depending on whether they are above or below geostationary orbit) into a stable elliptical orbit. Any part that wouldn’t go into orbit would be moving at the same velocity as the earth and would pile up at the ground attachment point. And if you’re still worried just put some parachutes on it.