Elevators in Space

listener mail. This listener mail comes from Alan, and Alan says Chris and John. I love your podcast and have a suggestion for a future topic. You mentioned in your rare Earth Metal show, the exciting possible uses of carbon nanotubes. I've heard that space elevators could be achievable with this new high strength weight material. Would consider a space elevator podcast. Thanks a bunch. Well, we considered it, and we decided to do it anyway. Yeah, this is sort of the

the area where stuff to blow your mind would normally cover. Yeah, but you know what, there's tech, so we're gonna talk about it, darn it, and we beat him to it. Yeah, I think so. I haven't gone through their entire list of of episodes. I don't know if they've done an episode about space elevators or not. But what is a space elevator? I hear you all ask. It's pretty much what sounds like. It's an elevator that goes into space. Yeah.

Like many things that we have talked about on this show, this was apparently originally conceived by a writer, Arthur C. Clark Gosh Fountains of Paradise, the guy I thought up a lot of stuff. He did he did well. I mean, uh, maybe not a lot of the things we've talked about, but we did talk about the geosynchronous orbit and using that for communications. That's something that that he came up

with for for for his writing. And in Fountains of Paradise, engineers build a space elevator on an island called temp Robane. Probably mispronouncing that, but I'm okay with that. Um. Basically, it's a uh, it's basically Sri Lanka, which is where he lived apparently in many respects I have I haven't read it, um, but basically he in the book this island is on the equator, which is kind of important. Um,

as we'll get to in a few minutes. But the idea of being that there is a something I guess the top floor in geosynchronous orbit, which would allow the space elevator to to have a tethered cable at the other end, and the elevator could move on that cable up into space and back. Yeah. The the element that's in geo secrets orbit is essentially a counterweight. It's uh. If you've ever if you've ever had like maybe a yo yo and you've done it around the world, that

would be the kind of the concept here. Um the except of course that the weight is not being um held in place by the cable so much as the Earth's orbit or Earth's gravity rather, but it is an orbit around the Earth. That essentially means that it's constantly falling. That's essentially that's what orbit tends to be. UM, but you're falling in this circular pattern or elliptical pattern, and

uh the cable is uh anchored somewhere on Earth. Some plans I saw had it uh an anchor that would be on a uh something that would be a platform in the ocean. Okay, So that's kind of an interesting idea of because that gives you a little more mobility and we'll talk about why that might be important in a little bit. It. Uh some others I've seen where they suggested that the cable could be anchored to the top of a very tall building, which is not quite as mobile. As it turns out, you aren't able to

move tall buildings around easily. When tall moved buildings move around, that's usually a bad thing. So, uh, why would you even consider a space elevator in the first place. Well, that's a very good question. The point is not to reach the top floor where the penthouse looks out into

a nebula. That's funny. I was gonna say the crab nebula. Um. Now, I was reading an article from NASA called audacious or audacious I don't know, and Outrageous Space Elevators by Steve Price um and he was the one who explained to me that this actually came from Fountains of Paradise. But um, the idea would be that you could transport people and things and possibly even electric city between the Earth and

space too. I guess space stations or other objects in space that might, um, you know, be useful for people to use. Um that was redundant. So uh, yeah, the idea being that you could carry things out into space and back without having to launch a rocket or you know, spend spend the time and money and and have to

worry about weather openings and things like that. Um, I assume that having a giant cable reaching out into space would produce hazards of its own, but I'm sure, but it would be a fairly affordable method of getting things out into space. Yeah. The Uh, that's the big point there is affordable both both of the fact that it's affordable and in general safer in the sense that whenever you have a launch, there are a lot of risks involved. I mean, we all know this because we've unfortunately seen

tragic results of launch is gone awry. Uh, So there's always an element of danger launching anything into space. It takes an incredible amount of energy to launch anything off the surface of the Earth. So you want to be able to cut down that energy cost. You want to reduce the risks. According to our article on the site we actually have how space elevators will work on how stuff works dot com, it was written by Kevin Bonser

and Uh. According to to Kevin, the approximate cost to put one pound of equipment or one pound of anything UH into space using a rocket based method is ten thousan dollars ten dollars per pound. That's more expensive than the really good cuts of beef at my butcher by by a couple of factors. Actually, uh. The by contrast, a space elevator could in theory deliver a payload of around UH at around a hundred dollars to four per pound,

significantly cheaper, right. Um. Yeah, the the NASA article actually quoted David Smitherman, who is UH Marshall's advance of NASA and the Marshall Advanced Space Projects Office. Um, and he's actually looked into the possibility of of UH creating a space elevator. Um and he said that, Yeah, I saw

um Kevin Monster's article. But the compared cost here, according to smither And, what Smitherman would be um, oh, shoot, about two hundred two dollars for a passenger with baggage at about hundred and fifty, So that's two not bad. Compare that to the massive amounts of money you would have to pay to go up on our Russian rocket to visit the International Space Station, as some as a

person I know actually did Hello, Richard aread Um. But the yeah, the the the article that we have on the side has some really interesting uh factors in there. You might wonder exactly how would this work? How would you get a machine to go up a cable all the way into space? Uh? Well, the the concept here is is really fascinating to me. It's a it's essentially a platform or some sort of enclosure, depending upon what you're putting on there, and it is attached to this cable.

The cable itself is not necessarily really thick either, because it's it's it theoretically built out of carbon nanotube nanotubes and I'll talk a little bit more about those in a second. Um. But the the platform has these robotic climbers that can either climb up or climb down the cable once they are powered. And the way you get power to the elevator is that has these photovoltaic say cells, Man,

I can't talk today either. We we recently changed our podcast recording time and our mouths aren't haven't caught up to the rest of us. But photo voltaic cells, so those are the same kind of cells like solar power cells, right, but these cells tend to be tuned to a different frequency of light than our solar power cells are UM they're used, they're made out of different materials. Are solar

cells are are made out of silicon. These are made out of other materials that absorb different frequencies of light. Then you use lasers or lasers to direct the light onto the cells, which then the cells will convert the light into electricity, which then powers the robotic climbers. So all you have to do, I'm making this sounds simple. All you really have to do just point your laser at the photo voltaic cell and it does the rest. Not granted it's it's definitely not in all you have

to do kind of thing. I dismissed that as being far too easy. But the idea here is that using light, essentially you are providing power to this platform which will then climb all the way up into space. Uh. And there have been some very variations on this idea where you might have multiple space elevators on the same cable and uh and they would kind of do sort of like a fireman brigade type thing where you would transfer the payload from one to the other, so you don't

have one UM one platform going the whole way necessarily. Uh, and it's kind of uh it depends on which which approach you read. Uh that that will tell you, like how how high up the counter measure is going to

be and how fast the platform will move. In the article on our site, uh, Kevin was talking about a company called Liftport that had suggested putting a platform that would be or acount of count of way, that would be two thousand miles above the surface of the Earth, and it would move at a speed of The elevator would move at a speed of around one miles per hour.

So I did some math. Yeah, that means that to to make the entire trip to go all the way up, not a round trip, but one way, it would take five d point four hours of travel, or around twenty two days. That's a long time to listen to the girl from Eponinus that song bum. Okay, that's all I can do before I get sued. But yeah, now that is that no one should be forced to listen to music for twenty two days straight. Excuse me, I got all choked up. UM. So yeah, it's funny that that

you point that out. I did want to make that point that this um the article is is very uh, is really kind of centered on Liftport's concept of doing this, because um, the version that David Smitherman suggested uses a little bit different um technology. Now, he said there were five things that needed to happen in order to make space elevators possible. The first thing is you needed high strength materials for the cables and the tower. Well, okay,

the carbon nanotube should probably cover that. I think. The second is, uh, you know, the the continued development of the tether technology, which I imagine is going on. I don't know that for a fact, Um, you also need lightweight and composite, lightweight composite structural materials to be able to build the towers and the buildings that necessary to make it work. The fourth is high speed electromagnetic propulsion. Um.

I'll get back to that in just a second. And then the fifth is the development of the infrastructure needed to support the space construction. So um. The fourth is the one that really applies to the difference between this and Spaceport because his version basically uses magnetic propulsion. Rather than touching the cable, necessarily you would be able to like a maglev train. It would basically you know, move up the cable without actually touching the cable necessarily, rather

than rather than climbing it. Um. And if I'm if I'm understanding it correctly, uh, which is really kind of cool. Um. I don't know how. You would have to be very cool. You'd have to have a really low resistance in those cables, so that would mean you have too super cool of course once you got into space. But it's a neat idea. No, it's a fascinating idea. I had not come across that

in my research, So that is an incredible idea. And the reason he suggests, the reason it's so important to have stations placed at the equator is the uh, likelihood of storms decreases at the equator, so you're less likely to have atmospheric interference with the space elevator traveling up and down the cable. Um. So I found that completely

fascinating because it's one of those things. I think the first time I actually came across the idea of a space elevator was in playing Civilization Too, So, uh, you know, I was going space elevator. What's that? How the heck is that even possible? Yeah? Because you sit there and you think about it, like, how could you do that? How could you get you know, how do you keep the tension on the wire. Well, that's easy, the countermeasure

does that for you. Because it's in orbit, we should yes, Yeah, until if the counter measure were to fall out of orbit, that would be a bad thing. Uh exactly, if something were to happen to the cable, that would also be a bad thing. It wouldn't necessarily mean the counter measure would fly off into space, because again it's an orbit, but it would mean that you would, you know, you would have a broken space elevator. You would have to find some way of either repairing or attaching a new cable.

Let's talk about the cables for a little bit. Uh, the carbon nanotubes in particular, which I find fascinating, you know, just by themselves. Yeah, carbon nanotubes are kind of like the miracle equipment of the future, right, I Mean it's like it's like that material that everyone's heard about and uh, no one's really like it's hard to explain exactly what it does or what it you know, what what it kind of functions, it may it may fill in the future.

Carbon nanotubes are made up of think of a sheet of carbon molecules and they are arranged in a heck like a pattern of hexagons. Yes, okay, so if you've ever had any kind of graph paper that was in hexagon form, I'm looking at you all my war gamer friends out there, um here okay, I mean the other ones. I've got more than just you. So anyway that if you think about it, you've got a sheet of hexagons all connected together, and then you roll that sheet up

into a tube that's essentially a carbon nanotube. It's it's takes this sheet of molecules, you roll it up, and depending on the angle that you roll this sheet into, um it has certain properties. So if you roll the carbon nanotubes or the carbon sheet rather one way, you're going to get certain properties out of this this carbon. If you roll it another way, you'll get totally different properties.

And you might think, well, wow, that's insane that you would just just by changing the angle that changes the properties of the material. But then think about what all the stuff that carbons in. Right, you look at the difference between graphite and diamond, one of the softest materials that we know about, one of the hardest materials we know about. Clearly, carbon has got some flexibility, uh figuratively speaking, so well it is. It is considered as flexible as plastic.

That's that's the line. That and it's stronger than steel if you roll it the right way, right and um, from what I understand to the idea wouldn't necessarily be to take a single tube and run it into space. They would actually braid these tubes together, which seems like it would make it in more. I would imagine you'd have to grope, yeah, because if you didn't do that, if it were a single tube, I think it would be so thin that anything, right, you just slice right

right in half if you came in contact with it. Um, you know, yeah, you're exactly right. It would have to be several all. When I say several, I'm talking like millions, all uh, interwoven together. And that's one of the big problems we have right now is just the finding the methodology to create carbon nanotubes length sufficient to work in this kind of uh you know, this kind of application. Right.

If we were able to do it now, we'd already have lots and lots of things made out of carbon nanotubes. So it's it's an ongoing process. I mean, you do find some products out there that have carbon nanotubes built into them, like um For instance, there's a some block, really some some block has carbonano tubes in it because of one of the properties of being able to um block harmful radiation. That's one of the cool things there.

There's also clothing that has carbonano twos interwoven into it. UM. There was the idea that you would be able to eventually create a Spider Man type suit out of carbonano twos because one of the the things you could do is make it so that it would adhere to surfaces, so you could actually climb up the side of buildings just by wearing the right kind of suit. It's pretty cool, huh, Except for my question was how do you get your when you put your hand down and it adheres to

the building, how do you get it off right? If it's strong enough to hold you there, how do you pull? And apparently it was all in the angle, at least in this sort of concept that this one scientist had for it. Anyway, that's an off track. I just I just had this image in my head of somebody, you know, successfully climbing a wall and the suit and somebody, can I have your autograph and I want my pen back. Sorry, that's done. You should do that's you know, I can't

get into my else anymore. My keys are stuck right here. Yeah. So anyway, the carbon nanotubes play a big part in this because it's it's a material that has the potential to to withstand the the pressure that the tensile um strength. It has the tensile strength necessary to fulfill this. I mean, you're gonna have platforms climbing up this taut cable and down this taut cable, you know, thousands of miles. It's

got to be strong. Yeah, And I think that's, uh, that's obviously since that's the very very first thing um that Smitherman said. You know, you've got to have something strong enough to to work for this cable, no matter what type of propulsion the elevator is using to get up and down the cable, you've got to have something as robust as something or like the carbon nanotubes. I am having so much trouble talking today. It's it's a

Friday morning, folks, give us a little break. So anyway, now, it's, uh, it's really neat to see that they've they've gone this far, but you know, what about the possibility that there are going to be whether problems with it or you know that the cable is going to break while somebody is in space, or even or they need repair simple repair

right there. There's also the issue of their stuff in space there what lots of there's lots of stuff in space as space, as it turns out, is big, really big, um the but there's lots of little things floating around in space that could potentially cause damage to either the cable or more likely the actual elevator as it was traveling through space. So debris, um, you know, anything from you know, meteorites entering the atmosphere to uh, you know, satellites.

Just the fact that some set, not all satellites are geospatial satellites, right, They're not all locked into the same spot right, In fact, most aren't, I think. So you get to a point where you have to figure out, well, what what do we do in the case of there's a you know, uh, an object that's on a collision course with the elevator. You have to be able to detect those things. You have to be able to adjust the speed of the climb or descent of the space elevator,

so it avoids them. Um And with the the water based anchor, you know where you've got the bottom of the cable anchored to a platform that's on the ocean, you at least have the potential of moving that platform so that you can change the angle enough so that the elevator will avoid whatever the object is, because even a tiny object could do a massive amount of damage the elevator. Because you think, if it's an object that's moving around essentially in the orbit of the Earth, it's

moving on an incredible speed. So you have to plan these things out. You can't just say all right, well, now we've got the climbing technology, we've got the platform, we've got the cable. Let's do this. You've got to be able to protect what you've just built. We can build it. We have the technology right well, and there were there were fears of terrestrial problems as well, not just weather, but people who might want to sabotage the

space elevator. Yeah, as it turns out, you know, when people come up with these brilliant ideas that are um there are potentially going to change the way we do something you know, massive like moving things into space. It means that we've invested a lot of money in time into that, right, and so what better way to strike at an enemy than to hit a spot that's going to you know that that was the result of billions

of dollars of investment and and and countless hours of time. Um, you know, take sabotage that and then you've struck a huge blow. So especially if you have something like a platform floating down in the ocean. Um, depending upon how big that platform is, you might not have that many personnel assigned to it, so it becomes an attractive target. This is actually something that people have had to think about.

I mean, it's you know, if you're if you belong to a terrorist organization and you're looking at potential targets, then you want to look at high impact and you want to look at the high probability that your attacks going to work. So, I mean, it's an unfortunate reality. So that's another one of those things that people have had to think about, like, well, how would we protect this?

And I'm pretty certain that whichever nation comes up with this, or if even if it's a you know, a group of nations that work together to create the first space elevator. I'm certain they will have incredible security measures around that. Yeah, yeah, I would imagine so. But I don't think we're likely to develop a working space elevator in the next you know, short few years. I think it's still going to be quite a ways down the road. Um. And it seems

like the logistical things there's a lot to work out. Um. Sure, you know, it just seems it's always seem risky to me to have a cable running that far out into space and expecting it to stay where it is. You know, it just seems weird. The aliens don't like that. The aliens, yes, they don't. Uh. And you know, I forgot about one of the other potential uses for a space elevator. The

thought is actually really cool. One of the potential uses is actually launching UH vehicles from the space elevator into space, because the idea here is that you don't need as much fuel UH and you don't need as larger rocket in order to go into space once you're in orbit, because you don't have to escape UH or gravity from

the surface. Right. So, so it means that we could cut down on the costs of space travel, and potentially use a space elevator as a launching site for missions into deeper space, like another trip to the Moon or perhaps two Mars or who knows. Yeah, it seems like as long as the elevator work capable of carrying that weight through the you know, up until it reaches the edge of the gravitational pull, significant gravitational pull, it seems like it would be able to do that. But I

can't imagine. I would have to be a pretty hefty elevator to carry something the size of say the Space Shuttle. Boy, it's gonna carry that weight, carry that Wait a long time, Oh man, I can't let you out here, Dave. Yeah, it's interesting because you know, the space platform is just above hardware and uh and tools and uh that's a long long wait. Yeah, it's interesting because although we're calling it an elevator, obviously it would feel more like a uh,

some other kind of vehicle. Yes, something like that. It would have to be if we were going to be traveling for multiple days. You know, clearly you wouldn't be like, all right, did everyone go before they got in the elevator? Because this is important. It's gonna be several days before we get to the top. So clearly it would be more like you know, it had to be bigger, yeah, and it would have a you know, facilities clearly would have to beds, things like that. Food Yeah, yeah, Food

would also probably be important. I would not want to go and not want to go between eight and twenty two days without eating. Um, I don't like going a

couple of hours without eating, tell you the truth. I wonder if I wonder if there's a way to send smaller things up the cable at the same time the elevator is like for example, uh, you know, you have the elevator going, and you have a small container of food, you know, for stay a week, and you send it on up and it caught up to the space elevator and they could you know, drop waste or trash or you know, I suppose a person breaking out because he's

in an enclosed space and freaks out an elevator. The longer you would the longer you go on the trip, Like, the closer you get to the top up, the longer it would take the supplemental material to get to you. Yes, it would, um, I would imagine that, but that would probably I wouldn't help prevent the need for carrying a

lot as much stuff. Yeah, I mean, if the robotic climbers are are powerful enough, it's not really an issue because I mean we're That's the other thing is we're not really thinking of Uh, you know it's space elevator is not the same as an elevator, and that elevators usually use cables to pull them up or lower them down, whereas in this case, the space elevator is using robotic climbers that climb either physically or magnetically in the case that you quoted the cable, So, um, I imagine. I

mean these these climbers have to be incredibly powerful. They have to be I mean there otherwise you wouldn't you know, nothing would go up the cable. Well, if there are any rocket scientists listening, you're happen to have any insight on that. Yeah, I just know I don't want to step into a space elevator. See otis on the door, and then you know, seven days into it, it stops and then I'm just sitting there. Essentially, you spent too much time on Martha equipment. Yeah, well, did you see

my tweet this morning? According to the sign my next train was arriving in one thousand, three d seventy four minutes. Rather I calculated that out. It means that I wouldn't be here until tomorrow. Well, it's a good thing that you are so that we can do this show. Um, it was very lonely without you last week. Okay, well I really don't have any else anything else. Yeah, Yeah, it's it's a really interesting approach. It's um. Obviously, it's an approach that comes with its own set of problems,

not all of which are trivial. But if we can get it to work, it will mean that we could rapidly, at least comparatively speaking, uh, shoot things up to say the International Space Station or bring it back down. Um. It would mean that we could build out other space stations. We could launch deeper exploration uh missions, whether they were robotic or human manned. Um, human manned, Well they if you, if you built enough of them, you could develop a

significant infrastructure in space to do all kinds of different things. Yeah, and eventually you could have a fantastic arcade game space elevator action. I'm not even going to touch that. Do Do Do Do Do Do Do Do Do Do Do Do? Alright, then hey, I love that game. All Right, Well, we're gonna wrap up this discussion. Clearly we're a little loopy, but no, space elevators really are an interesting idea. I'm

not sure we'll ever actually see one implemented. I hope so. Uh, there's certainly a lot of people who are really really smart who are working on this, who are really trying to make it work. Uh, and I hope there's a accessiful The projections for when we might see it tend to be around the end of around give or take a year or two um in either directions, So hopefully that will actually pan out. Yeah, you know, the thing that worries me more is not necessarily the technology, but

the logistics of actually making it happen. Yeah, that that actually seems to me to be the biggest problem. We didn't even talk about how they would get the cable there. Essentially, the idea I saw was that you would launch a rocket up that would be carrying this cable on a spool, and at a certain altitude it would start to unspool

as it continued to go up into space. So you would have the cable unspooling while it was still in the Earth's atmosphere and uh, then the rocket would reach its destination and stop, essentially um and possibly become the counterweight. That's that's one possibility is used the whatever vehicle you used to get the spool up there, use that as the counterway to secure it in space. There have been other suggestions that we'd use an asteroid, you know asteroid, yeah,

to to secure the cable to an asteroid and geosynchronous orbit. Uh, and then you would use an aircraft to capture the cable in the Earth's atmosphere and bring it back down to whatever you were going to secure it too. Yeah, it's kind of that's crazy. I mean, it's the whole concept is both amazingly awesome and insane. I could Yeah, I could do that. Yeah. So anyway, if you have any amazing, lee awesome but insane things to say to us, can you drop the insane part and just make it

amazingly awesome because the insane ones hurt my brain. But no, No, you can write us. You can actually contact us on Twitter or Facebook or handle at both of those is tech Stuff hs W, or you can email us that address is tech Stuff at hell Stuff Works dot com and Christen, I will talk to you again really soon. For more on this and thousands of other topics, visit how stuff Works dot com. To learn more about the podcast, click on the podcast icon in the upper right corner

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