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So our next speaker is Marcus Landgrab, who currently works for the European Space Agency ESA, you might have heard of them. They're like the NASA of Europe. He's going to talk about space elevators because, you know, the rocket equation is pretty it's pretty unforgiving. And the drive doesn't really get you out of gravity wells. So we might need a space elevator. Please welcome our speaker. Thank you. Who have you have heard of the space elevator? Who have you believe? Keep your hands up. Keep your hands up. Who have you believes to see a space elevator in their lifetime? All right. OK, I get the picture. So most of you have heard about the space elevator and about half, I would guess, believe it would become reality. So I would like to make it extra real for you tonight. It's about as real as it gets, I believe, because I'm going to talk about the elevator to the moon since I'm also a representative of ESA. I would also like to talk about what ESA does today to go to the moon and why to go to the moon. So let me give just a quick overview on why and how one, anyone can get to the moon and then talk about why ESA goes to the moon today or how we actually do that. And then we come to the really the the core of the talk, which is beyond rockets, going beyond rockets. And of course, that's the elevator. And then talk about benefits because you're a big community, you are very successful community. What draws you here? But what really draws you here is the benefits that drive you. Everybody, every one of you has is looking for benefits, for fun, for knowledge, for meeting people. And the community is really exists because you draw benefits from it. And that's also true for anything that we try to do in society. And space exploration is part of that. And that brings me to the final point, which is the community. I would also like to share a couple of links with you that will enable you to engage in the space elevator in lunar exploration in general and with ESA, of cour
se. All right. Enough said about the overview. So why the moon? This is a little fun bit that I put together and I would just read it to you. I will not comment on it because it is a bit the folklore about space and the moon, and you can form your own opinion about those things. Some of them. I will also talk during my talk today. So there's this famous guy by the name of the casing who, of course, says that Apollo was filmed in a Hollywood studio. Everybody who likes to watch British animated films knows Wallace and Gromit, and they insist that the moon is made of cheese, which solves that cracker problem. Of course, you all know the Apollo program that ended in 1972. So there is an issue of the TIME magazine that says soon robots will be intelligent so there is no need to risk human lives. 2010, President Obama said while talking about his vision on the space program that we have been there before. And I will leave that without any comments. And there's another nice movie by the name of Aaryn Sky and and that movie. Yeah, I like to. And then, of course, in that movie, you have President Sarah Palin and she says that who are these guys anyway? Nazis from the moon, Wahaha. So so this is, I think, very inspirational folklore about the moon. Let's get to the to the real thing, why we explore space. Now, if I say we I always am in these talks with ESA, I'm always talking about us Europeans. But the European idea is bigger than Europe. So so let's just feel as Europeans for a minute, because the moon is in our exploration DNA. We Europeans are explorers. And I just visited my hometown of CUSA in Hessen, south of here a couple of last days, and I took a picture there in a museum. And that's a picture of 18th century artist scientist who made you observe the total eclipse of the moon. And he did that under contract of a nobleman in CUSA who sponsored artists, scientists to come to his court and teach about science. So already, two hundred years ago and even earlier, we ha
ve been really engaged in science because we understand this is part of our cultural heritage. Actually, this nobleman is the grand grand grandson of another nobleman who hired the Swiss guy to come also to CASA to measure the position of the stars in the sky at the time, a very difficult undertaking because the sky, the stars move in the sky due to the Earth's rotation. So you have to know the time very well. If you want to tell what is the position of a star, because it's if you don't know the time, it's moving all, all, all the time. So this guy used Bourgie, made a clock and that clock was so precise and it needed a third indicator, which was the indicator for the second. So the second the time unit second was invented in my hometown of customers. Not many people know that. And that shows that exploration is not only in our DNA, but it is also to our benefit, because without the second hand on our watches, we would be in trouble. Now, these days we don't need them anymore. But but it tells you that our everyday life is really much inspired by inspiration and inspired by exploration. Of course, another reason why we should go to the moon is discoveries now a little bit arguing against President Obama. We have not been there. We have been in a couple of places which are very special, but the moon is largely unexplored country. There's a nice book by Arlene Cross University Press. You can get it for cheap on any even as you book. I believe that beside him there is a new moon. Many of the most dramatic recent discoveries in planetary science are lunar. Only in the past few years has lunar exploration accelerated again, and many do not realize how rapidly our knowledge of the moon is changing. Have just put the two pictures here that are from recent observations of the moon. The upper right one is a hole that was punctured by a meteorite in the roof of a cave on the moon and the underground world of the moon. We have no idea what's inside there. And of course, the fi
rst idea that comes to everybody's mind is we could live there. We could be protected from meteorites and from solar radiation. The lower image is in this very mysterious region is called enough. And Einer is apparently the tip of a volcano, ancient volcano that blew away this dusty lid of the moon. So what you see here, this more bright stuff is probably the real surface of the moon while the rest of the real surface is still hidden under this dusty, little bit more dark, what people call the regolith. So there's so much more to explore. And certainly if aliens would come to Earth and would take a couple of samples in the Sahara Desert and some in the Gobi Desert, they could not claim that they've been on Earth and have explored Earth completely. So here's a philosophical take on it. And because it's philosophy, it has a lot of text and will not read that. I will ask you to read it after the talk and then report back to me what you take from it. Now, I will just say the basic idea. So there are two school of thoughts. One school of thought says there's limits to growth. Earth will run out of resources soon. So we better be very careful with them and the other school of thought, which is much less famous. Says there there's a limitless amount of resources because we are connected to the universe and the letter one is called The Extraterrestrial Imperative, was formulated first time by Cruft Ellika, a German philosopher philosopher who was also part of the team of the Fondren engineering team that went to the United States to build the moonwalk. And he basically says nature has shown to us that whenever there is a limit, evolution will overcome that limit. And he gives the example of phytoplankton, which is a bacteria or a single celled organism that ran out of energy at some point but discovered the use of extraterrestrial energy source, which is the sun. So to plankton discovered by evolution, how sunlight, which is extraterrestrial, could be used to make energy an
d store energy on Earth. And by the same token, he says, human technological development is the kind of evolution and we will be able to overcome that. And how do we overcome that is pretty clear that we use resources that are not from this planet. So this is the extraterrestrial imperative. The third reason why we should use the moon is, of course, you see this nice gravitational well that is made by the earth and it's difficult to get out of it because you need energy to get out. But the moon creates an extra spot there, which has this interesting structure that allows us to put spacecraft in a equilibrium state and put it like stations there so that you can reach the surface of the moon as well as deeper into the solar system. So really, these three things we can it's in our culture, it there is new knowledge to be gained and it is a great starting point for further exploration. So these three things are reasons to explore the moon. Why is it so hard to go there? Why are we why did we stop? And the reason is the rocket equation. This is the rocket equation formulated by Konstantin Sikorski in 1895 is basically an expression of the Newtonian law of mechanics that says to each reaction, you need an equal but opposite reaction and this is the only way to propel yourself in space. If I'm walking across the stage, what I'm doing is I'm pushing the stage behind me so that I'm propelled forward. And the the link that makes it possible for me is my soles of the shoes. If there was if there was a slippery surface that would not allow the transmission of momentum between myself and the stage and we just slip and fall. But if in that case, I would have to use reaction principle of Newton to propel myself. And in this formula there's a very important parameter is the Delta V that's on the left hand side, which gives you the amount of how much you have to change your velocity to reach a certain target. And in the lower part, you see the numbers here that are not very importan
t, but it's very difficult to get from Earth into low earth orbit, which is the first little gravestone there, and then three thousand two hundred meters per second to go to the lunar vicinity and then on top to go to lunar orbit, to need another 800 and then to the surface of the moon, you need two thousand. If you know that our current technology limits us to use exhaust velocities, which is the V, they're of less than 5000 meters per second. That tells you why we need big rockets to launch small payloads. We need a 10, 700 ton around five rocket to launch a ten ton satellite into geostationary transform. And that makes it so expensive. Now, expensive means what is the economics of space transportation? And what you see on the right hand side is much more interesting. This is a table of how much it costs today. If you would go to a launch service provider to launch your stuff into space in Earth's orbit is about ten thousand euros into cislunar space is ten, ten times that or a hundred thousand to lunar orbit. Two hundred thousand down to the surface of the moon, one million euro, one kilo to bring anything back from the moon. Ten million euros. So if you even would get back platinum or the most precious stuff that you can think of, it's still cheaper to get it on Earth. So forget about the space economy with rockets that will not work. The only thing that the private sector can do is they can make space travel more efficient so that for the governmental players, everything becomes a little bit cheaper. But there will be never be able to get stuff from the moon and sell it here on Earth. That's just physically impossible. If they use rockets and the left hand side, you see that actually the. The cost raises with the square root of the matter. So if you have a big rocket, it's more expensive, but the rate of increase is lower than one. So that means that for each kilo, you'll pay less if you have a big rocket. And that's why around five is, for example, bigger than
 our own four. So this is the economics of space transportation in this situation that we have today. And in that situation, ESA has a program that that takes us indeed to the moon. And I think just to sleights about how ESA goes to the moon today, like I said, the biggest problem is gaining access to the moon. And that is why there is the big blob and there is the little bit smaller, but still a challenging problem of surface operations. And these two problems really break down into smaller bits. We need to get to the moon. We need stagings. So we have to change the vehicle. You know, let it let some stages that already spent the fuel go away so that everything is lighter than we need landing, which is difficult because it's difficult terrain. And then we also have to launch from the moon, which is something that is incredibly difficult given the fact that already launching from Earth is difficult and then you can break it down further. And each of these topical problems has a program, for example, to get humans astronauts go to cislunar space. We are cooperating with NASA to build a human space vehicle that will launch first time in 2018 around the moon. Issa proposes a program to build a habitation module for this cislunar habitat. This is a habitation staging post in this house, in cislunar space that will enable access to the lunar surface, but also into deeper space than ESA works together with Roscosmos, the Russian space agency, to build a landing system for lunar applications. And there is a camera that will first go in 2018 2019 to prepare our technology for landing on the moon. And then further down the road, we're working together with an international consortium or with international partners to build a demonstrator mission that does everything so we land. We would take off and we have a little rover that shows mobility on the surface. And this is an integrated system that we are currently proposing to our member states. And I would like to play the par
t of the essent getting away from the launching a rocket from the moon. The problem here and then the final problem that we face is habitation on the lunar surface. And that is, of course, challenging is perhaps not as challenging as habitation and free space, but still there's difficult problems. Another topic that still needs to be addressed is getting resources from the moon, not necessarily to make money from it. Like a plane is probably not going to be a good profit, good business. But we already have a payload that tells us how we could use resources to sustain a base on the lunar surface. So now this is a little bit of a time arrow arrow here to show you how we want to develop that over over time. So the first thing is like a show. This is the drill and the camera, and that goes already in 2018 and 2021 in two missions together with Roscosmos. Then there is the Orion vehicle, first launch in 2018, the first human mission in 21. Then the cislunar habitat are going to be built up somewhere around the mid 20s, perhaps a little bit earlier. And then this interesting demonstration mission in the mid 2026. And then ESA does indeed plan or propose in cooperation with international partners to have a human mission or a series of human missions to the moon to really start the exploration. But all of that is still limited by our transportation problem. But that's what we can do today. Like, I promise that that's the realism of the situation right now. But let's go beyond this goal. Let's go beyond rockets. When I said that it can propel ourselves only in space, only by pushing something back by actually equals the actual. I lied a bit, so I was not completely honest with you guys, because if you have a physical connection to the planetary body that you're orbiting, then you can transmit momentum. And that physical connection is created by a space elevator. And the basic principle, I think really many people in the room already know it. So I will skip tours quite quickl
y. The idea is to have a long rope and the rope as the center of mass and that center of mass is orbiting the planet in sync with the planet's rotation. So in the end, the rope will touch the surface of the planet, but will not necessarily exert a force in it. So it's simply it's like a satellite, but it's going around the planet at the same rate as the planet is rotating. And then you can climb up and down that rope with with the cabin. You make a nice cabin around you with air and you can go up and down. And I'm not I know you're your heads are full of questions and I'll try to answer some of them. And certainly the broader space elevator community can answer most questions today. So just as a start, the energy actually is not so much the problem. Indeed, we still have to provide the energy to go from Earth's surface up into the gravity. Well, but that's only one kilowatt hour per kilogram. And how much is a kilowatt hour in Germany today? It's like 40 cents. I guess that's twice the price than in France. But never mind. It's still cheap enough, right? Then the climate can go up and down with electric energy. Has electric motors attached to that cable can go up and down. The cable is actually kept port by the forces of gravity and center should centrifugal force. So gravity pulls the part to the left down and centrifugal force pulls it to the right up so that the cables always taught then of. As the climate goes up and down, the climate creates what's called the Coriolis force, and that puts the sideways force on the cable and the sideways force creates a wave in the cable. And what does the wave to look much because of the high tension on the cable and then left hand side, you see a couple of wiggly lines, which is the free motion of the elevator. And if you can read the small numbers, we are talking about 700 meters of maximum amplitude of of that. And if you go to higher vibrational modes, it's it's really not causing a lot of a lot of vibration in terms of spa
tial vibration. Of course, the cable for Earth and this is the Earth cable would be 150, 4000 kilometers long. So this is not to scale right on the Y axis. You have one hundred fifty four, forty four thousand kilometers. And the Y axis, you have just kilometers. And you see that is the free motion of the cable. And by introducing a little bit of wiggle on the base of the cable, you can even manage that vibration. So if you have a vibration on it, you can cancel it out. So no problem. And the other side shows you what happens if the climate goes up. And this is actually on the moon. Cable is taken from a paper by Pearson Atoll where when the when the climate goes up, you will have a bit of oscillation in the order of a couple of meters normally. But that's not certainly manageable. OK, so let's talk about strong cables because we need strong cables to kind of not make them rupture. So what's the strong material like to express strength of a cable in terms of rupture length because it expresses the strength of the cable at the same time as its Pacific weight? The rupture length is the length of a cable you can suspended vertically in a 1g constant 1g without it snapping under its own weight. So steel cables are pretty strong. You can have 11 kilometers if you make it 12, it would just go bang because of its own weight. Carbon fiber goes up to three hundred thirty kilometers and a mystical. Material that's called material nanotube that exists only laboratories in very small quantities makes it up to three thousand three hundred kilometers for Earth, you need for Earth Elevator and you need about two thousand five hundred kilometers of rupture length. So so this mystical material would be able to do the earth elevator. So and there on the right hand side, you see other materials that are available today and you see somewhere figures about 250 to 500 kilometers length. The longer the better. Why does that? Why is that important? Because the magic of the taper people have
 been asking, how strong does the cable have to be to make a space elevator? And there was a paper by Jeremy Pearson at All in Astronautical 1975, and he explains that we can do it from any kit, any material can even make it from steel. Only you have to make it much thicker at the center of gravity than you make it at the base. Now, this paper shows how that is called becomes so extreme for the Earth that for Veck materials, that elevator becomes not feasible. So I show you this magical material, nanotube material that allow us to have a space elevator from Earth with a table ratio of about eight or so material that exists today is, for example, carbon fiber or the famous honeycomb polymer. So that these are fibers you can buy in the shop today and you can see for Earth it would be like thousands of times thicker. And it's not a problem of making something bigger. But if you make something you start with, say, a centimeter and you have to make it 10000, 10 centimeters wide at its widest point. And the whole thing is four hundred forty four thousand kilometers long to total mass of this thing becomes humongous. So that's not going to work. So. So but for Moon and Mars, this is much easier. You can see. And the reason is, of course, the moon and Mars have lower gravity and they have slower rotational rates than the Earth. And then you end up saying that with existing materials. If I have a taper ratio of about eight or five or four, I can I can make an elevator. So why are space elevators easier on the moon than on Earth? We have a feasible ribbon material now. We call this thing a ribbon. And I will come back to why we call the rope a ribbon. We have very few artificial satellites around the moon that could potentially collide with the cable. And we have no human made space debris around the moon and there is no atmosphere on the moon that could kind of with chemical reaction, damage to cable. And there is no there is no strong trapped radiation in because there's no
 magnetic field around the moon. So so the elevator around the earth is quite futuristic. It is quite science fiction. But the elevator around the moon, it is still science fiction, but it's closer. So it's not two thousand thirty one is 2000, 2001. So if you compare the movies, then you know what I mean. Right. So one word about the climber. I know that climber is the most inspiring part of the space elevator, but it's by far not the biggest problem. And in my life, I always try to crack the thickest nut first. So, you know, one day when somebody gives me that cable, I will start talking about the climber. But there's a nice concept out there that basically runs on two wheels. You have electric motor and you have solar arrays providing the energy and you can have a couple of capsules attached to it that transport the transport the payload. So what is it that we get out of the moon elevator? Why should we do it beyond exploring the moon? Well, first of all, you'll remember that diagram, right? What made us a lot of headaches and stomach ache. But if you have space elevator, the first thing that goes away is this because you can go from one orbit to the lunar surface. So this change in velocity that you need to make in order to go from one orbit down to the surface all of a sudden goes away. So your rocket has to do much less work. Not only that, only this number goes away another 800 meters per second because you're starting already in the lunar vicinity. So this goes away. Your rocket makes even less work. So all you have to do is basically now you have to launch an Ariane five rocket. You get seven tonnes to the lunar surface today with an Ariane five, you get about five hundred kilos. So less than, yeah, roughly 10 percent of it. But if we had let's speculate a bit. If we had also an Earth elevator, you could also cancel those two figures. So the number that you see for Delta V becomes zero. That means you can have a free transfer from the earth's surface to the 
lunar surface. No propellant needed in that show. You in a minute how that looks like. Not in a minute. I show you now, right. This is a computer program is publicly available on the Web. And I have the URL shared with you. In my final slide and what I've done, I've played with it and you see this in the crosshairs, you see the earth and downward pointing is the earth elevator. And on this central ring, you see the moon with the long line and extending with a blue dot at the end. That's the moon elevator. Now, I put a payload, that's the little green dot down there and me and find my cursor so I can play with it. OK, so there is my payload, right? So now I'm starting to let the earth rotate and you see the time scale up there is 512. So it's a fact of 512 over real time. So the earth rotates and the payload goes with the elevator, of course. And while the earth rotates, of course, the moon is moving slightly but much more, much less fast when this reaches the 90 degree position I let go. So this payload will just be detached from the cable and then this will describe a freefall trajectory to whatever it takes it because of the loss of gravitation. And then now I have speeded up to eight thousand one hundred ninety two to make it a little bit faster. So you don't have to wait to sit here all evening because things as they go farther away from Earth, they go slower. And then what you can do and you see now every turn of the earth is, of course, one day is that at some point you find a trajectory where you can this object can fly a rendezvous with your moon elevator and you can just latch on and then descend on the moon elevator all the way to the lunar surface. So so you would have a direct connection from the earth to the moon and the other way round from the moon, you can bring any material, platinum, gold from the lunar surface back to earth without any use of propellant. And of course, what that would do is to enable us to make real use of space, economic use of s
pace. We could create structures that are so humongous that they would just no collect enough sunlight, for example, 24/7 to provide earth with energy. This is a little animation showing you use microwaves to beam the energy down to to the earth's surface. And and you can make these structures, you can make space hotels, because all of a sudden you've broken this, you hacked celestial mechanics. And I think that's the basic idea. This is why there is interest in the space elevator. So my final thought here is that perhaps if you want to engage in space exploration, in the moon exploration and I would also like to point you towards the talk by my boss, actually, and Werner, the director general of ESA at 8:00 and in room number one. And he will talk about the Moon Village and how this community will make it happen, that we will engage into lunar exploration. And final word on the community. Here are a couple of links, emails, Twitter names and URLs that you can use when you download the presentation to make it happen and be part of the space elevator. Thank you. We have a rather generous half hour for Q&A, so please get ready to queue at a microphone for questions. There's basically microphones everywhere such as queue and also, of course, as always, we have questions from the Internet. So if you're in the chat watching the stream, we'll take care of you as well. We'll just start with a microphone to please. Hello. Thank you very much for your dog. So what I was wondering is that you do not mention at all if there is going to be an extra problem that the cable will have to take care of. That is the stretching due to the difference in gravity as it goes along the gravity? Well, is that going to be a problem or is that a very minor factor? Thanks for the question. I hid that, of course. And the answer is that the purest model is made such that the tension on the cable is constant through the cable by making it thicker at the place of the biggest force. Because, you kno
w, tension equals force divided by cross section, squared by cross section, and then that's taken care of. OK, thank you. Before we get to the next question, just a little announcement, please try to be quiet. And if you need to leave, leave very, very quietly. And if you don't have to leave very urgently, just do us a courtesy and wait until the end of the talk. Thank you. Uh, could we get an Internet question, please? Could we get the microphone, please? Question working with, OK, is it already known how the elevator affects the Earth's rotation? It does not at all. There's, of course, a small value, you know, that by nature affects the Earth, speeds up VirnetX contracts because of its cooling down. But it normally it slows down because of the presence of the moon. Attaching a Aluna cable of about a thousand tons will not affect any because the moon is much more heavy. Could we get microphone number seven, please? My question is, what will this mean for future further space exploration missions that what are the implications for further space exploration missions starting from the moon, or does that have other any implications for this? Thanks for the question. Yes, they are. And of course, that's part of the deal, that we try to prepare deeper space missions by making propellant on the lunar surface and then transporting it into cislunar space, which could be then the starting point for Mars missions or Jupiter missions or even at some point missions to Proxima Tantowi. But that's an extra torque. Thank you, Mike. Number one, please. Thank you for a great talk. I'll try to keep the question brief and feel free to direct me to the next talk by your boss if you feel like he could answer the question better. But it seems to me that most of the reasons for going to the moon. Apart from the science, of course, which is important, could be solved easier from Earth orbit. I'm thinking specifically of a refueling spacecraft and I believe that the low Earth orbit fuel dep
ots could be refueled from asteroids and you wouldn't need to build a space elevator on the moon. I'm with you 100 percent. And of course, my boss can answer any question better than I can. But let me give it a try. Let me give it a try. Of course, that's actually my day job. So I'm looking at architectures of exploration to find out what what's the best way. And you're right, if you were if your goal was to have a Mars mission or a series of Mars missions that use refueling, then you would perhaps not use fuel from the lunar surface. You would use asteroids and transport the material, not necessarily to low earth orbit because of the high penalty. But you're right there. There's competing things. And the real reason for this lunar elevator to just make it clear is if you want to exploit the moon economically for not necessarily use it for further space exploration, but for bringing precious metal to the earth, that would be the real reason for the denial of it. But do we not also have access to those materials and the asteroids? Not necessarily. If you have to bring it. If you have to bring it out of interplanetary space, because you have to then fly a reentry trajectory. And that is very expensive. But let's take that offline. Sure. Thank you. Do we have Internet questions? Yes. Why are carbon nanotubes or graphene sorbent materials? Can you repeat, please, I didn't catch the. OK, not to a carbon nanotubes are graphene has been in the materials that have talked about a lot, we haven't read this whole bed materials for the elevator. No, there are good materials, but they are not there yet. That's the thing. I gave a talk in 2002 13 on TotEx. Whoever wants to Google Duncalf space elevator finds that on YouTube. And there I am talking about how to make that possible. And and you can tell from my talk back then that I was a little bit younger at the time and a little bit uncertain. So and that's why. And then it's and that's exactly the reason is that that the nanotub
es are not there yet. So thanks for the question. Number eight, please. So high up here, high up there. You talked about that we have the material to build a lunar elevator, but not the Earth one. So is it possible to make the Earth cable just shorter and then use a rocket to connect to the lower part of the elevator? That is true. And you were invited to give a talk next year about that. Now, it's yeah, there's a whole community out there about space tethers and yes, there's options, but there are sometimes risky because you have to fly around the room at the end of the cable. And ESA even was involved in tether experiments back in the 90s. So, yes, there is a community out there that makes it possible. But the real benefit that solves a lot of operational problem is when you create a real elevator that actually attaches to the celestial celestial body. I have a follow up question. If you have a space tether, don't you need fuel on board to reposition it, otherwise it flies away or come back, correct? That is correct. And normally people you'll ever solve that problem by making a low thrust transfer using solar electric propulsion or using the Earth's magnetic field by putting in electric power. So there's all kinds of solutions for that. Oh, thanks. Could we get No.6, please, when you travel to the moon and the obvious advantage of rocket space transportation is that you can more or less freely choose the point of your landing. So with that space elevator concept, allow to reposition the the elevator so you can more freely choose where you're going. Yes, there is a paper that I'm citing also in this talk by Pearson in two thousand five or eight, where they basically connect the elevator to a tramway. So they bend the elevator a bit to higher latitudes and then starting from that higher latitude points to a tramway. But in any case, you can once you're on the surface, you can drive. I mean, oh, come on, take your take you over. Always drive and just go. Or there's 
more easy solutions to that then than with a rocket. And you're right, with the rocket, you can choose your landing site, Frehley. Could we get my number three, please? Yes, I have a question about the failure state and how it differs from for Earth cable and the moon cable. So I would guess an Earth cable would burn up in the atmosphere. If something goes wrong, what would it be for a moon cable? So so first of all, the moon cable, if it disconnects so that there is one part coming back, it would just impact the lunar surface and be destroyed upon impact, normally with high velocity impact to get a complete obliteration of the material. And about only 10 percent or even five percent stay on the surface. The rest goes into the solar wind. But that that doesn't have to take place. You can always sever the cable on purpose when you have a break. And there are a couple of other things are the reasons that I didn't explain in my talk why potentially you can make it so that the cable never breaks. Make number four, please. I your slides that the calculations about to Caban Wobble were taken with elevator speeds of about 250 kilometers per hour, calculating that the cable from Earth would be about 150000 kilometers long. I make that four point five weeks around that. So the whole transfer would take multiple months. Yes. Are there any plans on sending humans up with that space elevator or would it be like cheaper because they're faster? The only reason we have unmanned space program is because you can you cannot make small humans. And and if you have a system that is so capable, like the space elevator, you would take humans from day one. So. So, yes. And they would just have the food for four, five, five months. OK, thank you. You're welcome. Well, technically, we have small humans, very small. But could we get another question from the Internet place? Yes. How about the vote that's generated by the magnetic field of the elevator? Would it be a risk or another source of 
energy both for the Earth elevator? It could be a source of energy or depending on the material you choose. But for the moon elevator, there is no voltage because there is no global magnetic field around the moon. Number eight, please. You saved a space elevator from Earth is not possible with materials. We know what is about a launch loop or. Something a so you talk about you try to connect both ends of cable up to the earth and oh, OK, I haven't looked at that concept, never heard of it, but thanks for the inspiration. I will look it up. Launch love. You said, though, like they have both hands on the earth and then with centrifugal force you can. Yeah, OK. The tension will probably be the same. But let me let me check it out. Sounds interesting. Thank you. Could we get number three, please? Coming back to your question from the beginning, whether we will see it as in our lifetime or not. Can you give an estimate, maybe an optimistic or realistic estimate on the time line? How far is the research? So. So if I was president of the world will have it in 2050. It really depends very much on the decisions that are taken on a global scale and these days just look at the new US administration and some movements here in Europe that are detrimental to the efforts of gaining more knowledge. So but if we take the path of knowledge, I'm pretty sure that will have more. Well, yes, I plan to have a moon program in the 20s, 30s, and the moon village will be implemented that Boehner will talk about. I'm pretty sure we'll have a permanent settlement on the moon somewhere in the mid 20s, 30s. And then and then the necessity of having the efficient transport system will force people to build a space elevator. And that will be then 20, 50. And I plan on being around that long. Make number four, please, on the topic of focusing resources, so we talked about the cost effectiveness of rockets, but we didn't talk about reusable rockets as push for now by Elon Musk and SpaceX. I was wonde
ring if you could talk about the cost effectiveness of reusable rockets versus space elevators in terms of focusing our resources that we have currently. Right. Great question. Thank you. We know from Elon that that rockets, reusable rockets are about 30 percent better than your reusable ones. Right. So that brings down anything back to the moon from 10 million to nine hundred nine million seven hundred thousand per kilogram. So that's great. But it's still rocket technology. The space elevators are estimated to lower that by a factor of 100. Now, that includes the initial investment, but assuming that the initial investment will be less than 10 percent of the turnover. So the turnover, of course, you have to put a lot of business in it to make it work. And that's that's the problem with the space elevator. If there is not enough business for it to do, then people will never engage in it. Mike, number six, please, so thanks for the talk. And first, and so from our talk, I guess that the moon elevator is currently already technically feasible or suitable. So are there any plans or what's the timeline? The ESA has not it does not have a space elevator program. We have made a couple of experiments with space tethers that were quite successful and we have that in our knowledge base. The reason why ESA is not engaging in it is because our task is to enable research for our member states. And research is not the prime target of the space elevator. There is a space elevator consortium and you will find something on the for example here, the one that I showed the lift part dotcom. You will find that they have a timeline in them and it's a private consortium and their plan is to make a business case for the space elevator. OK, thanks, Mike. Number two, please. Thank you at first. Thank you for the nice talk. I have the question. There's often the argument that we shouldn't engage in human space travel because of the costs and the risks. And it's really, really hard. What wou
ld you give as an argument against that? So I'm in space business in 16 years, so I have answered that question in a couple of times. So forgive me if I feel a little bit superior at this stage. So so first of all, the cost is not tremendously high. And don't forget, any euro that you put in the space program does not go to space. The euro stays here. And we've done a benefit analysis by ESA that roughly for each euro invested by our member states, they get five euros back. And I can tell you about the details if you if you want. The second thing is that that space is right now we're looking at about one percent or less than one, much less than one percent of national spending. So there is not a big part of the national budget. The third point about the risk is human space flight risk is really only to the astronauts. And they have a contract that says you have a risky job. Are you ready to take that risk? And they say, sure, go, go, go ahead. And so that's the risk bit. And that was it, right? Yeah. As opposed to the point that we can do it without humans or people tell me I'm not really behind this. Tell me we can do it without you. And so why don't we try? So I cannot exclude that possibility that someday we will have intelligent machines. But I've tried to know I've I've fooled a security camera the other day by just having my glasses, my shades hanging out of my mouth. Right. Not putting them on. Just put them in your mouth. No security camera will recognize your face. So so that tells you there is not intelligent computers today because the security sector has billions and billions of euros to spend on this stuff. And like I said in my beginning in 1972, there was an article which said that there will be intelligent robots very soon and I am still waiting for them. I'm sorry, but it could be there in 20 years. No, could be. Thank you. Could we get the Internet, please, if this is a quite practical question, however, to deploy and fix the cable. Yeah, that's a 
brilliant question. And I skip that in my talk and apologies for that. Thanks. And that's why the question gives me an answer opportunity to answer it. So the rocket would bring roughly a hundred to a thousand tongue cable to the libration point to this stable point that I showed before. And then from that point on, the cable would be deployed at the same rate upwards and downwards, maintaining the center of gravity at that stable point and doing a little bit of station keeping, not too much. And once deployed, it will stay there for decades. So so then after that you can launch another rocket, very small one with a with the climber and fly rendezvous, attach it and then it could go up and down any time. So it's really and I would prefer that the person who has asked the question also to the space elevator, Vickki, that I'm listening here on my links because there is some information there. Mike, number three, please. I have two questions, the first one is, how are we going to build the cable? Is it are we transporting materials from Earth to moon or are we going to mine it from there? And the second question is, how are we going to build the cable? Are we using, like, 3-D printers? So so first part of the question, both options exist so you can bring everything from Earth there. That's the more expensive way, but the more safe way. The other alternative is you bring a small pilot cable and then you start building strands of the cable and pull it along the pilot cable up and then make a thicker cable out of the pilot cable through through a that's cheaper and less risky one. And a yes, footprinting printing is definitely an option. And I actually deleted one slide that showed how the structure of the cable is because I wanted more of your questions. So I deleted slides. So so the the idea is to have like a crisscrossing set of strands that would allow the breakage of one strand without the cable breaking, or you can make it breakage of five strands without breaking 
of the cable. And by that way and also that would allow then crews to go up and fix the cable if there is a broken strand that would go up, displace the cable and then get the strand out, put the insert the new splice and pull a new cable thing and adjust the tension on it. Thanks. Could we get number six, please? Arthur C. Clarke have never thought of paradise and where you described the elevator concept and they have many papers written about this concept to using hyperbolic structures like all independent oil drilling platform are using it also. And I would like to know they have already calculated an equation how much how much time it takes to lift up a human being from Earth to Earth and the sea global space exploration strategy. This is because it looks like the International Space Station will be up until 2025. At least the financing is secured until then. And what it will be after is also possible to use his S4 as a springboard, as is often mentioned to the moon. OK, you think so at three parts, right? So, yes, an orphan of paradise, a very good book. And it's really about the economic and socio economic impact of a space elevator. So that's very interesting things worth mentioning that now the technical solutions and discussions that are in this book and Arthur C. Clarke as an engineer are very interesting. And honestly, I haven't looked into them so, so very much. There is a lot of interesting solutions there for the anchor point. The second part of the question was about the the travel time, and that was answered by a colleague before. So we're talking about months. If you have a slow elevator, you can speed it up. You know, you're in a vacuum so you can go a thousand kilometers an hour without too much damaging your haircut. So so that would work. So cut it down from a couple of months to a couple of weeks. And the third question was the global space exploration is the International Space Exploration Coordination Group. And thanks for that question, beca
use in that group, we're preparing the next steps together with NASA, with Roscosmos, with the Chinese space agency. And the next step will very likely be the creation of a small staging outpost in cislunar space. Could we get microphone number one, please? Yeah, OK, thank you. Two small questions. The first ones might seem a little naive, but once the elevator is in place to climb up the elevator, wouldn't that apply a downward momentum? How do you keep the edge of the rope in place? Right. Yes, but it's so small that the one ton cabin you would have a you would have a thousand tonne cable, No. Two ton the two ton climber would have a thousand tonne cable simply because of the math, how it works out. And you can check the papers. So the Sea Org would go a little bit slower, lower, and you can compensate that by a little bit of motion below its intricate. So the horizontal motion by a mobile platform that travels 100 meters on the lunar surface can compensate, can provide the energy to attach it. Once you have attached to this cabin, then it climbs up and the COAG will approach again its original state. But these are menu changes and mainly they they cause oscillations that didn't have to be managed in horizontal mode. OK, and the other question was, say we managed to build an elevator on the moon, but the whole technical thing for the earth just doesn't work out. And so we are stuck with just an elevator on the moon. Yes. How useful would that actually be? So so the usefulness of that and get back to that image is. This so you cut to the delta in half, enabling reusable rockets going to and from the moon, so it will be about half as expensive as it is today. So you cutting from 10 million to five million? Is that enough for our economy? I don't know. OK, so it would be better, but it wouldn't solve the problem at all. Exactly. OK, thank you. Number two, please. So you talked about economy and I wondered, is there any concerns about who owns the moon or may we face 
the next war on resources in 2050? That that there is a there is a consensus officially by the UN, which means that nobody can no nation can own the moon. And that includes, by the way, private companies, because each private company has to have its legal framework set up by a nation. But, of course, you know, things always go different than the official ways. And already now there is a lot of discussion about who owns the moon. And I think we'll have to wait for the war. Maybe that's a chance to occupy the moon. Could we could we get a question from the Internet? Traveling from wooden back to Earth via elevator, would you amend the U.S. atmosphere to break or would you have to have some propellant you don't need either? Because when you go down on the cable, you will keep rotating with Earth. So unless there is a high altitude wind, there will be no friction with the atmosphere. So we would basically go that the air would become ever denser. As you go down. Basically the first 100 for the one hundred forty or more than one hundred thirty thousand, no mass on stage is just terrible mental mass on stage. You should try it one day. So. So the first ninety nine point ninety nine percent of the cable will be in vacuum and then the last bit, the last 30 kilometers. So so you know, one hundred forty four thousand minus 30, that's 30 kilometers. You would be in the air and then you would feel the air becoming thicker and of course, high in the atmosphere. You have some winds, you know, you have the jet stream. But at that stage, you will still be in your little cabin until you reach about 3000 meters when you can basically get off the lift if you want. One last question from number one. Please make a chart if you can. Of course. Thank you, Mr. President, for the nice talk of actually. My question is quite similar to the one from Mike to just now, but not the question who would own the moon but who would own the elevator? Because if you're not the president of the world, ob
viously in space, things go far better together than on Earth, like an ISIS and something. But due to the cost of the elevator, what do you think? Will it be a public project like with either NASA or will it be something like SpaceX and private investors? That's a very interesting question. My my pretty and I really haven't thought this through, but my answer would be very likely it's going to be private because the benefits are really intrapreneur benefits by getting material from the moon or building big infrastructures in space that offer services. So so I would guess would be private. And then your question is very relevant because it's a huge, powerful piece of infrastructure. Is that even possible to have a private entity owning it without interfering with national interest and national strategic interests? Because in the end, you could bomb any place on the Earth from that elevator if you want. So perhaps some nations are not very happy to have a private company controlling this thing. And that is a little bit also addressed if you if you read Arthur C. Clarke's Fountain of Paradise, because then this whole problem becomes very clear. And I don't have a good answer for you. Sorry. Thank you. So we are out of time. Please thank our future president.