What is keeping us from anchoring a cable to Earth’s surface and tethering a platform in space?
In: 10077
that’s the concept behind a space elevator.
it has a number of issues tho:
1: we do not know of any material currently that could take the stresses involved on such a long cable.the ones that might, cant be manufactured in industrial scale yet.
2:in order for such a structure to be stable it needs a very specific location(somewhere around the equator that’s geologically stable) and the space part of the structure needs to be far enough to achieve geosynchronous orbit(especially considering said cable needs ot end in a significant counterweight iun ordwer to be able to tense up)
3:such a system requires that a significant counterweight is put in place on the other end of the cable(in order ot keep the cable tensed up), we do not have the means ot get such a thing in orbit with current tech.
4: the existence of a such a structure would give its owner essentially a monopoly over the Earth’s orbit(since it would make the cost of sending stuff into orbit plummet) so it would be a political nightmare that would likely spark wars, so you need the right political mindset(aka, you basically need world peace)
The concept you’re describing is called a space elevator, and the good news is that it doesn’t break any laws of physics, so all the challenges are engineering. That doesn’t mean it’s easy. It’s not.
– the cable. It needs to be light and crazy strong. There have been some promising developments here, but we’re still a long way away from anything practical.
– a counterweight. If we have a cable up to a space station, the cable actually needs to go further and end up tethered to a big counterweight. So we would probably need to capture a small asteroid or something heavy and human-made.
– add concerns about space debris and terrorism. Fun fact, if broken, the cable would fall and encircle the earth two and a half times
The launch platform would probably be at the equator and on the ocean.
Getting stuff into space is the hardest and most expensive part of the process. A space elevator would be a huge achievement in allowing us to get materials up there at a fraction of the cost.
So, bottom line, this is doable, but we’re still a good way away from it moving from science fiction to reality. This is a huge, difficult, expensive project with technology that has yet to be invented but I’m very optimistic that we could see something in my lifetime.
Most of these answers here appear to be right on track. In theory, we need to turn toward spiders’ webs. And, scientists ARE working on it. It won’t be long.
Meaning, a spider’s web, upscaled for human capabilities in flight, could stop a Mach 3 jet… better than any technology we currently possess.
In the end, you’re going to read a lot about “carbon nanofibers.”
Tethering an orbital platform to the Earth has been an hypothetical for nearly a century. They call them ‘elevators.’ but for all intents, it’s a way for a line to be attached to an object in orbit.
Sounds simple enough, but in practice, not easy at all…
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Try to imagine what would happen if something went horribly wrong and a 40k kilometer long cable broke loose and started falling to Earth, which is 40k kilometers in circumference and constantly spinning.
Most of these answers here appear to be right on track. In theory, we need to turn toward spiders’ webs. And, scientists ARE working on it. It won’t be long.
Meaning, a spider’s web, upscaled for human capabilities in flight, could stop a Mach 3 jet… better than any technology we currently possess.
In the end, you’re going to read a lot about “carbon nanofibers.”
Tethering an orbital platform to the Earth has been an hypothetical for nearly a century. They call them ‘elevators.’ but for all intents, it’s a way for a line to be attached to an object in orbit.
Sounds simple enough, but in practice, not easy at all…
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All the top comments are bringing tensile strength, but another major issue is resistance to heat and friction.
While most of a space elevator would be outside the worst of it, the portion between 0 and ~80km is going to be experiencing drag from the atmosphere. While it’s possible to make it long enough that the counterweight balances out the drag which would make it *collapse*, that’s tens of kilometers of material which is being consistently blasted by air going speeds of upwards of 450km. That air carries ice and dust.
You would make the assumption that since it’s high altitude it’s cold, which it is, but relative temperature matters a lot in this case because so far humans don’t have any materials which don’t become brittle at low temperature. On top of that, all the strong stuff we have has very low ductility (the ability to bend and shape).
So the moment, even the stuff we have that is theoretically strong enough *also* becomes brittle at low temperatures *and* can’t withstand the friction.
There’s actually a fantastic point in *Project Hail Mary* where this problem is addressed. It’s by Andy Weir, the guy who wrote *The Martian* (which the movie is based on). I definitely recommend it.
All the top comments are bringing tensile strength, but another major issue is resistance to heat and friction.
While most of a space elevator would be outside the worst of it, the portion between 0 and ~80km is going to be experiencing drag from the atmosphere. While it’s possible to make it long enough that the counterweight balances out the drag which would make it *collapse*, that’s tens of kilometers of material which is being consistently blasted by air going speeds of upwards of 450km. That air carries ice and dust.
You would make the assumption that since it’s high altitude it’s cold, which it is, but relative temperature matters a lot in this case because so far humans don’t have any materials which don’t become brittle at low temperature. On top of that, all the strong stuff we have has very low ductility (the ability to bend and shape).
So the moment, even the stuff we have that is theoretically strong enough *also* becomes brittle at low temperatures *and* can’t withstand the friction.
There’s actually a fantastic point in *Project Hail Mary* where this problem is addressed. It’s by Andy Weir, the guy who wrote *The Martian* (which the movie is based on). I definitely recommend it.
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