I've read the books too and I think they've done a pretty good job given the circumstances. You very well know it's an impossible book to convert into a movie. It's very heavy in political discourse and there are too many paragraphs where there are just a bunch of people sitting in a room talking. That doesn't make for good cinema.
@@PVilarnovo I'll answer your question with another question: why not make it? The more people that know about the series the better, even if it's just a TV adaptation. If anything, it could be their gateway into the books. The Foundation series needs more recognition for its colossal contribution to science fiction. Ideas such as hyperdrives, laser weapons and star wars were first envisioned in the series.
@@dannybodros5180 so… we will recognize the importance of Foundation with a series that has nothing to do with Foundation besides the name of the series and the name of some of the characters? Makes no sense.
The first scene of the underrated "Ad Astra" begins with an incident in an orbital elevator. And "The Fountains of Paradise by Arthur C. Clarke" is a classic about this theme.
And I don´t remember the books ever mentioning a space elevator. the first space elevator description I ever saw in a book was Fountains of Paradise, by Arthur C Clarke. And then of course, the Mars Trilogy books.
I’m glad I stumbled across this channel, I’ve been fascinated with the idea of a space elevator since reading about one in the Mars trilogy by Kim Stanley Robinson, and I’m glad they put one in Foundation, I’m sure Asimov himself would have considered the idea too much when he was writing them originally, he admitted as much before he died too… it fits for this story.
Great video! I remember a similar scenario in Red Mars by Kim Stanley Robinson with another space elevator built, then sabotaged above Mars. It's been years since I read it, but I vaguely remember there being equally dramatic results. Like one of the scenarios you mentioned, the book used an asteroid as the station/orbital end to provide the required mass to keep the cable taut. Due to the transit times it seems like a realistic space elevator would be more useful for cargo and bulk materials than passengers.
Thanks! I still need to read Red Mars, it seems like a really good book! I think you're right, space elevators would be ideal for moving non time critical stuff around. I'm not sure too many people would want to spend a month to commute into space!
Transit times are on par with long distance travel in the modern world. And both are vastly faster than travel in the past. Just because a rocket will do it in a few minutes doesn't mean a few hours is unbearable.
Due to Mars' lower mass, the cable isn't as long as what would be needed by Earth, and also due to Mars' much thinner atmosphere, the cable didn't burn up on the way down, and it was still long enough to wrap around the planet a couple times.
@@tonygoinggonzo Also IIRC it was tethered to one of Mars' tiny, porous moons and the weight of the cable brought it down. If I've remembered this wrong please tell me and I'll go and write my own space opera :)
@@GavinMorris1 it was tethered to and built using materiel from a captured asteroid. during the same war they blew up one of the moons, but I can't remember if it was Deimos or Phobos? when they rebuilt the elevator, they used another captured asteroid
Suggestion: You wrap the cable in superconductive wire and put a few hundred amps through it. In case the cable were broken the strong magnetic field would bring the ends of the cable together again so it wouldn’t fall. OK, you’d have to go up and actually strengthen the cable again at the break point but you wouldn’t have to start from scratch again. As the magnetic flux lines are parallel to the direction that the transporter chamber would take when transporting people and freight to and from orbit, it wouldn’t apply any extra force on them, and would only be a problem with it’s interaction with the earths magnetic field which would cause the cable to tilt towards the pole. Actually that could make the cable a little shorter.
Would bring a lot of complexity to the system and in 99.99% of the cases whatever broke the actual cable (which is ridiculously strong) would also break the wrapping wire.
@@ItsMySpaceship You're right about the complexity, but on reflection, you wouldn't need to use wire, you can use a sheath, like shielded wire, and have the current just flowing inside the shielding. The shielding can also be extreamly thin, sub-micron. OK, granted you would need to use a high temperature superconductor. But there is some evidence that carbon nanotubes could be strong enough to form the backbone of the cable, and also some evidence that nanotubes are superconductive under certain circumstances. Maybe we can circulate a current through the cable itself and so produce a strong enough magnetic field to pull the broken ends together again. I know all this is speculation about things that we don't yet know how to make, but it's still fin to play at "what if...".
@@martinstent5339 Why would there be a magnetic field if the superconductor is severed? Current flow would also be severed, so no field would be created.
@@TheHalcyonTwilight because the current is going AROUND the wire, and not along the wire. It means you need an insulating core in the centre of the supercunductive wire, but that only needs top be a few molecules thick. The current going around the wire creates a magnetic field along the wire lengthways and can't be stopped by breaking the wire, so if the wire gets broken you will immediately get a north and south pole very near each other and they will pull back together.
Fascinating and informative. I remember reading Arthur C Clarke's novel featuring space elevators (Fountains of Paradise) and being intrigued by the whole idea so its good to see the science behind such a construction so well laid out. Thank you.
@@stefanr8232 they do have anti gravity. It obviously wouldn’t be used to increase the gravity, it would be used to counteract it. Anti gravity implies advanced active suspension. You could make it so that there’s no stress on the cable. Yes obviously that tech would make the elevator pointless especially since they have the only space elevator and presumably the thousands of other planets get by just fine without them. Also they’d need to use some sort of active gravity since their ships are capable of containing Planetary mass black holes without ripping themselves apart.
@@stefanr8232 I would assume anti gravity is energy consuming, theres a reason we send so much freight by slow ships rather than hovercraft, even though we have the tech its not economical to use it in all cases.
Magic would really help with all the engineering problems of an Earth space elevator. Magically producing a million tons of cable of supersophisticated materials. Magically getting elevators to be able to crawl up it. Magically damping vibrations. Magically healing radiation and micrometeorite damage. Magically eliminating electromagnetic effects along thousands of kilometres of cable. Most people and trades that want to travel in space would just get out of deep gravity wells and stay on nice little rocks.
Only applies to geosynchronous. Need to recalculate for trantosynchronous. Need the number of seconds in a day, the acceleration of gravity at the surface, and the surface escape velocity (or radius). Luna is low enough gravity the elevator could be made out of materials currently on the market. For Haumea the elevator is so easy we could almost build it as a tower under compression but not quite. Mild steel or cotton is easily strong enough for Haumea under tension. On Phobos we could do it with corrugate boxes and stretch wrap and it would support itself with both compression and tension.
There is no currently available materials, however the tensile strength of carbon nanotubes is suppose to have a sufficient margin. The problem is a) it would need to be a continuous (perfect) nanotube, b) we cannot make the stuff in sufficient quantity or quality
When you describe what happens to the top of the elevator once the tether is severed, you said it would simply rise to a higher orbit. Actually, the top of the elevator would simply enter an eccentric orbit instead. Before the tether is severed, the entire elevator is orbiting the Earth its center of mass, in a circular orbit defined by the length of the tether. Once the tether is severed the two parts now each have their own center of mass. The topmost part is traveling too fast for the orbit it was previously in and would act like a spacecraft firing its engines directly downward toward the Earth, accelerating instantly outward. This would push it into an elliptical orbit were it would continue to lose velocity until it reached its aphelion, at which it would start to fall inward toward the Earth, gaining velocity until it reached its perihelion, where it would be traveling too fast to be pulled all the way back to Earth and be flung outward again. This is similar, to a Hohmann Transfer maneuver, it which a spacecraft in a lower orbit needs to rendezvous with another in a higher orbit. One thrust burn puts it into an eccentric orbit going outward. Another burn is needed to make its orbit circular again.
In the show the severed elevator station does fall back to Earth years later but is detonated into debris before it hits the atmosphere to avoid a great impact.
Didn't see your comment before I post my own, arguing the same point. One correction to your is that Aphelion only applies to solar orbits. Apoapsis is the generic term and Apogee is in Earth's SOI. As I stated in the other comment, the proper terms for Trantor's SOI are probably Apotor and Peritor.
@@2nd3rd1st The station should NOT fall back to earth (lower case E). The lowest point in it's new orbit should be the altitude it's new center of mass was at when the cable snapped.
@@Corbald But the orbit would decay slowly, and in the show considerable time passes between the elevator getting free from Trantor and Empire finally making the call to demolish the remains.
@@cheytacsnipes Yes, but not that quickly. Most of the orbital decay experienced by artificial satellites in Earth's orbit is caused by interactions with our atmosphere. While it gets very thin, our atmosphere extends nearly to the moon! Even still, objects in _geostationary_ orbit (or beyond, as the platform would have to be) experience _very little_ orbital decay. It would take _centuries_ for it to decay enough to pose a threat to the planet. An example of this is that there are still fuel tanks in orbit of the Earth from the Apollo era, and the Apollo 11 lunar module is likely still in orbit around the moon.
I've been watching tons of Space Elevator stuff recently and Issac Arthur has a great channel where he covers all sorts of science and sci-fi stuff (shameless plug for his channel here). One idea that he mentions is that the station at the top could be attached by more than one cable. This would not only provide stability (fasten anything with three different guide ropes as an example), but the other cables would act as the buffer if one were damaged or destroyed. At a high enough orbit the station could be powered by the sun and it could even become a solar power station, sending surplus power back to Earth. As for the 'wrap around' effect from a falling cable cut high in orbit, it would take a lot of explaining to convince me that the result wouldn't be a horror show that would make 9/11 look like a fender-bender. Even if the cable weren't very heavy, it would still be traveling at terrifying speed both because of gravity pulling it down AND the rotation of the planet winding it up like a string around a yoyo.
Great video. I had wondered about which elements of the space elevator worked and which might not. Your explanation about the forces involved, the orbital speeds, and how where the break occurred (as well as the likely mass of such a structure) impacts the aftermath were enlightening. The engineering behind how to actually create such a thing must be astounding.
6:29 - You're counting the total distance to the counterweight, though. The actual space station could be half way along the cable (in fact, there could be multiple stations at different altitudes).
@@CharlieQuartz - The one in the show does several physically impossible things; the example he was giving was an attempt to get (the main part of) the physics right. He even correctly called that mass "the counterweight" (not "the station"), but then measured the distance to it and apparently forgot that there could be a station (or several stations) at different altitudes.
There is a better option that will make space elevator as a children's toy it's called ORBITAL RING and no magic material needed much higher throughput
An orbital ring doesn't get you to orbit though. You try to step off into the void and you fall back to earth instantly. You gain altitude and you get out of the atmosphere, but to reach orbit or leave to another place in space you still need something like a rocket to gain delta and get there. You are still under something like 90% nominal earth gravity, to get to orbit at the altitude you are already at you still need most of the fuel mass you would have needed if you launched from the surface.
@@DrewLSsix true but u can use a simple linear accelerator and as u are in vacuum u can reach orbital speeds easily and dude to size u have more than enough length to do it
I believe that once we have the infrastructure to build such an object, we will no longer need such an object. Also, the tether may not do much damage, but what about all the elevator pods/carts with people or cargo on them? In order to make these economical, you would need a lot of traffic going up and down at the same time and each one would probably be much denser than the cable. Also, a space elevator is not more efficient. It requires the same amount of energy to reach a particular orbit for a specific amount of mass. It just matters where you get the energy. Today a chemical solution does seem much more expensive (although a lot quicker), but don't forget that your object has to reach the top and then burn some fuel to adjust its intended orbit or escape velocity. Also, don't forget the fuel will need to be used to help with station keeping. That heavy counterweight will need some pretty nice RCS thrusters as the orbit will never truly be stable, especially when you consider all the forces acting on the cable and the dynamic amount of mass entering and leaving earth through the cable/station changes the center of mass. There are a lot of problems. These problems are/should be solvable. But just because they are solvable doesn't mean the solution will be practical. I am willing to bet that once we have confidence in building such a system, we would also no longer need to build it. But then again... who knows.
Nonsense. First of all, it isn't about whether you NEED it. It's about the expense it would save. If you could DO something but it cost a thousand times as much to do it one way as another, would you not do it the cheaper way because you don't "need" it? And yes, it IS much more efficient, and you need MUCH LESS fuel, because you don't need to lift the weight of the fuel, and the extra fuel needed to lift the extra fuel, and the extra fuel needed to lift the extra fuel needed to lift the extra fuel, which is the problem you face with using rockets. The rocket equation is an exponential function for this reason. If you had a space elevator, you could have the thing POWERED by an electrical station ON THE GROUND. That is why it would be much more efficient. You really don't know what you're talking about. You know what they say, it's better to keep your mouth shut and worry about the world thinking you're a fool, than to open it and remove all doubt.
The thing is I agree with your pointsd 100%, but keep in mind for many of these exact reasons the space elevator makes a great 'make work' project and show of empirial 'greatness'. It's kind of an Arch of St.Louis thing.
but having such a thing would save so much energy you would otherwise need to produce the chemical fuel aswell as saving the energy said fuel would waste in heat while being burned. you could power it electricaly, which is much more efficient then chemically, via a giant solar farm or even a nuclear power plant. once it is set up, you wouldn't need as much energy as you'd need with a rocket because you don't need to waste it anymore to fly around the earth fast to get into that orbit, you can just go straight up. having such a thing set up, could be a turning point for a young space fairing race. think about the possibilities, you could even have a little shipyard as the counter weight station and start building spacecraft in space. you could just send all the ressources and materials up with the elevator. wanna have a satelite in orbit, no need for big fucking rockets anymore, just build the satelite there and launch it without a launch vehicle. wanna send one of elons starships to mars, no need for the super heavy booster, just build the ship there and send it to mars. of course there is so much stuff to consider with these things but still, having the technology and the ressources to build this new infrastructure and not do it would be very stupid.
@@Rekcoj Firstly I did have a response to earlier comments that, for some reason, got deleted or was never posted that did bring some of this up... not sure what happened to it. 1) "but having such a thing would save so much energy you would otherwise need to produce the chemical fuel": Ok sorta. The 'economy of scale' will undoubtedly reduce the price of fuel significantly. So while a space elevator would use theoretically zero how much are you saving? And what are you gaining/losing? Do not get so hung up on an advantage, for there are always disadvantages. In our history, we have invented many technically better things that never got used simply because of some other unaccounted for disadvantage. 2) "you don't need to waste it anymore to fly around the earth fast to get into that orbit, you can just go straight up.": What about objects or people who wanna leave orbit? Want a lower orbit? Not every satellite will want the same orbit. Also, the energy provided to the cargo by the time it reaches the orbiting station is not enough for the mass to achieve circular orbit. It will need its own propulsion and fuel to leave the station and circularize its orbit. The station itself will have to have station-keeping thrusters that also burn fuel. It is nowhere near the same amount as the current rocket launch, but the point is that a Space elevator doesn't completely remove the need for fuel. 3) "think about the possibilities": This is not an argument for space elevators. All space elevators do in theory is provide reliable and cheap access to space. The possibilities can come from any technology that sufficiently provides reliable and cheap access to space. This argument would only be valid if space elevators were their only option. And it simply is not. 4) "and not do it would be very stupid." Humans have done this very thing countless times in our past. Sometimes it is seen as short-sighted/stupid while others times it was clear why. My main argument is the 'chicken and the egg' situation. That once we have the technology, confidence, and infrastructure to build a space elevator, we wouldn't need one. Because a Space Elevator is a megaproject that would first require technology, confidence, and infrastructure that provides reliable and cheap access to space. ---- Also, cheap!? Really!? The unsung hero of space flight is the launch pad. Easily more expensive to build than most rockets, and it is costly to maintain as well. The prep before and after each launch isn't talked about because it's boring. It's all about the rocket. But it is easily the second most expensive part of launching a rocket. You wanna make a product that probably costs 1000X as much as a launchpad to not only build but to maintain as well, and then claim its gonna make space cheaper!? Really? Why because it doesn't burn fuel? Fuel is one of the cheapest parts of space flight. And again, as the production of a newly in-demand product increases, its price usually drops significantly. Going forward, fuel is gonna be even cheaper, and it already isn't a serious concern. Lastly, if we believe we can achieve something like a space elevator in the future, then what about all the other future tech that is possible. Single Stage to Orbit reusable craft? In-takes that liquify oxygen as it passes through the air to 'breath' so you don't have to have all the fuel on launch? Hyper-Sonic plans. All of these things are possible and have been or are being researched. And that is just what could come out in the next decade or so. What about 50 years a 100? A nation like USA would likely push for that before letting some country on the equator control 'cheap' access to space.
Would definitely recommend 'The Space Elevator' by Dr Bradley C. Edwards. Great read, spends a lot of time on the physics, logistics and economics of elevators. All we need is a CNT ribbon that can self support about 30 000 tons and is about 50,000 miles long ...he didn't say it would be easy :)
In episode 3 of Foundation, many years after the attack, the Empire brothers discuss what to do with counterweight that is orbiting the planet. The counterweight is orbiting, as you expected.
The brothers also decide to Nuke it instead of rebuilding it.... Which makes no sense whatsoever because you can use it again and another question is it's been 30 years...why hasn't it been rebuilt...?
@@Shinzon23 That's an indicator of how the empire has decayed. It's one of the main points that were predicted by psychohistory (at least in the books and yes I know they didn't have the elevator).
I love how it takes less than the length of the video for commenters to come up with the solutions that the empires greatest engineers somehow failed to foresee over their lifetime of designing and building the elevator. Anyway, it does not matter how the elevator broke in the story, its used as a plot piece to show that the empire is not infallible and leads to public doubt in the empire sowing the seeds for the future.
Back here on Sol, rather than Trantor, space elevators for Mars are more easily achievable than for Earth. About the same rotation, but lower gravity, translates to less strength needed for the cable. Not sure whether you can keep Phobos around with a space elevator. Might need to use a sky hook with Phobos as the pivot.
I gotta say, people seem to REALLY forget about the kind of voltage and current levels we are dealing with when we are talking about making an object that is going from the ground out beyond the magnetosphere. If you have ever seen the footage of NASA's tether experiment in low orbit, the crazy plasma formations produced would give you a good idea of what is going to happen to any space elevator type object. It's not just a matter of tensile strength, you're talking about trying to handle insane amounts of charge in an optimal situation much less trying to deal with large solar flares.
At first, the lower part of the cable would fall slowly, but the upper part would snap like a whip at hypersonic speed. It would send a huge continuous shock wave around the globe as it enters the atmosphere (like when the asteroid exploded over Cheliabinsk) and if it reaches the ground, you would face way more destruction...
I think Foundation got it right. You can't treat as a point mass because the elevator size is large compared to the size of the Earth. Any parts of the elevator out to 80% of geostationary orbit will crash into the Earth over about 4 hours. The final pieces will hit the Earth at about 10 km/sec. It won't be pretty. When it hits the Earth, it will be shorter by about 20%. Even if it's in one piece when it starts, it will tear itself apart as it falls. Things from 80% to about 150% will go into orbit around the Earth. After that it's iffy. They showed an exceptional example of how it would fall.
Robert Forward has done some interesting speculation (with an eye to the physics!) about the space elevator and several variants not requiring any geostationary orbiting. [ interesting point, some of his designs are chain-drive! ]
Tbh, I don't think a space elevator should be the endgame but relatively early in a space faring civilization. That way our ships, depending on their purpose, don't have to consider taking off from the planet but can be built in orbit.
You can build the in orbit right now if you so wanted - you just need to get resources from space (other objects with low gravity well - asteroids, moons...) instead from Earth. You will always have a problem of going to orbit from a planet. But there are two approaches. One is to build an entire ship on surface, then launch. That is a huge waste. The other is to have large ships in orbit and some system to just facilitate surface-orbit transfer. And, in fact, that is what Space Shuttle was originally designed to be. It was supposed to be a truck that would transfer people and what not to orbit, and then other craft up there, nuclear powered, would take over. It was supposed to be a two stage system. So the thing you've said - it was actually planned. Just not with an elevator but multi-use rockets instead. And the end game for a civilization is a ship like Millennium Falcon - one that does not care where it goes, it is the same to it. Is such a thing even possible - who knows. But that is the end game concept for space travel :) Elevators are simply not that practical. A lot of resources spend, and one damn huge target. Not to mention that is one accident away from global disaster. Earth is showered by meteorites all the time... and you'd have a gigantic piece of infrastructure that has to endure everything that humanity and space can throw at it... for several centuries... in order to pay itself off? I am not holding my breath.
Kim Stanley Robinson is a brilliant writer. Profound incite into human behavior. Unparalleled ability at describing scenes. He is not a physicist though. He actually makes fun of a few errors in later books. I recommend reading both the Mars trilogy and later publications. I would not use them as orbital physics reference.
@@stefanr8232 I have only read Red Mars of all of his books so far. Got sidetracked from the rest of the series by other books from other authors a while ago and the profuse profanity and sexuality makes me hesitate to return even though I very much enjoyed the story. Call me a prude, but I wasn't raised that way and so such elements didn't add to the story, only distracted me. I have the same problem with Tom Clancy.
They should start with a moon prototype and test orbital compensation techniques. Work on a 140km rubber ducky building, 5km long 2km under water with a hyperloop
One thing missing here is that space elevators were not a new concept created by the writers of this TV Series. The Foundation series was of course originally written by Isaac Asimov and published from 1942 onward. Additionally, Arthur C. Clarke's and Charles Sheffield's (both published in 1979) are generally considered to be the works that introduced space elevators to the science fiction community at large.
If you pay attention during the Halo 3 ODST Mission on at the Zoo, when they pass and one of them makes a comment about the Space Elevator snapping. You can see the Elevator cord in the middle shoot up into the sky as its support rings fall down.
In Kim Stanley Robinson's trilogy about the terraforming of Mars, one of the books -- I think it's late in the first book, "Red Mars," a space elevator is sabotaged and there's quite a good description of what happens on the ground as a massive cable long enough to reach high orbit comes crashing down & wrapping itself around the planet. (If it's not in Red Mars, then it's in one of the sequels: Green Mars, or Blue Mars -- I recommend them all for anyone interested in "hard" SF.)
Thanks for informing me there is a Foundation TV series. I didn't know! I have read EVERY one of the Robot. Empire and Foundation books. Including all the "connecting" like
I'm very sad to say if you enjoyed the foundation books then you probably won't like the Foundation TV series. The apple TV series should have a "Adapted for TV from the Foundation Series by Isaac Asimov" disclaimer.
So I had an idea on how to possibly get space elevators ''soon''. Stage 1: Copy the movie Geostorm and create a net around the world in which there are satellites to control weather phenomena to prevent natural disasters. Stage 2: Start the construction of a frame on the net around the world creating part/s of the basic frame of a ring world. Stage 3: Build space elevators up to the frame. With this we can transport materials directly into space without rockets much earlier, meaning less wasted resources. The distance will be nowhere near as far as a traditional space elevator meaning less transport time while if made of the right materials the frame will be able to support it? Not only can we create multiple space elevators for the cost that just 1 traditional would have cost but we can build shipyards on the frame and so many other things. Not only that but stage 1 is also essentially a prototype terraforming system, meaning we could learn all kinds of things for when we start to colonize other planets. I am by no means an expert, this is just an idea I got out of nowhere.
Some of the stuff I see in the tv series I recognise in books by...Arthur C. Clarke. He too posited that it would be more practical to build on on Mars. The trick would be to tune the bean stalk so it would bow allowing Phobos and Deimos to pass safely. In terms of energy consumption, as with conventional elevators you have a counter-balancing compartment at the other end of the cable. As one ascends the other descends. The challenges of a beanstalk on Earth are described in his novel Fountains of Paradise.
The question is when you have spacecraft that have some kind of anti-gravity that lets them land and take off from planets directly, what do you need a space elevator for? 11:00 make the cable thick enough for massive traffic and even a low density material will have a high enough mass to surface area ratio to carry its momentum through the atmosphere. More feasible to build are orbital rings, tethered rings, and launch loops.
hmmm, you forgot something, the elevator would short circuit the ground to the solar wind. there would be a massive flow of energy from the van-alan belts to the ground, normally we see this as Aurora and red and blue sprites above dense cloud formations. such a structure could create a pretty spectacular light show and cause, some interesting ground voltage, EMF/RFi effects at the point of ground contact.
A method to mitigate the damage that a severed falling cable would cause would be to detect the point where the break had occurred and at that moment sever the rest of the cable up into much smaller links where each link would settle into a slightly lower orbit. They could eventually be rejoined from the top down as long as the links had been designed with contingency thrusters to maneuver them back into place. There are still other ways to space now possible without requiring rockets or super long singular space cables. Think tethered concentric orbital rings. That’s where all the plastics/co2/carbon fossil fuels should be going to - raw carbon based construction material - we will need a crazy amount to pull it off.
Great video as usual! I actually thought space elevators are very dangerous and can cause catastrophic damage but you clarified that pretty well. The fall of new mombasa elevator in Halo 3 was awful guess thats what made me think they were dangerous lol. And I think why we cant make space elevators probably is not because they are not scientifically possible as you said, but rather that its not possible production and economics wise. Even if we find the perfect material that fulfills all requirements, imagine how much of a challenge it is to produce 40,000KM of that stuff. And not to speak how expensive it will be. It will a massive and unrealistic undertaking for a single superpower like USA and will porbably require a multi national consortium and thats where politics will come. Even if we figure out science, it'll take a very long time to figure out the economics and politics to make it possible.
I think Halo 2/3 was the first time I saw a space elevator, and it certainly left a lasting impression on me as well! Space elevators would certainly require a very stable political climate. It's quite easy to imagine scenarios where control of the elevators controls the world in some way. Hopefully humanity will work out the social and technical issues of elevators sometime soon!
The space elevator is destroyed in the opening cut scene of halo ODST / the end of the 3rd or 4th human mission of halo 2. However, the elevator is severed at skyscraper hight when the ship enters ftl. So most of the elevator should have floated off into space right?
The issues I have with Space elevators are: 1. Everyone talks about when it is operating, but no one explains how you would build such a space elevator… perhaps you can explain how such an elevator can be constructed… do you pay out the cable from space to ground, or take the cable from ground to space… as an engineer… I am not interested in ‘well it just get made..”… I am interested in practical solutions… perhaps you should do a video on that would show your mettle… 2. You need to take into account the atmospheric drag the cable would have, because such a wide cable going through the atmosphere will have a considerable wind loading pressure and force applied to it 3. Electrical potential voltage across the cable.. especially in space. This is because of the experience from the application of space tethers on the space shuttle that were cut because the high voltage difference and high current through it burned out the space tether. This voltage can be induced by cutting the lines of earth’s magnetic field, and the charge particles coming from the sun, and at 40 000 km in length will this space elevator be in the Van Allen belt?
Seems like Red Mars had a relatively realistic approach. Kick one of Mars' moons to areostationary orbit, use automated machines to convert its material into the tether material and use the remaining mass as the 'anchor' and space station. Seems like the real trick is inventing a tether material that's strong enough to resist all the forces you've mentioned as well as micrometeorite and debris strikes and other dangers, while still be light enough to not just collapse under its own weight within the higher gravity regions closer to the surface. Correction: I think they used a captured comet injected into mars orbit, since the higher carbon content of the comet made it useful for manufacturing massive amounts of carbon fiber.
More accurately, the orbital platform wouldn't raise it's _entire_ orbit, just the Apoapsis, with the (new) Periapsis being at the point in it's orbit where the cable was severed. Apotor? Peritor? Dibs on naming credit!
Also: If the cable snaps near the base, it would begin to spin in it's orbit, around it's new center of mass, until it coils up. Initially it'd resemble a sky-hook, until it's orbital dynamics and self-gravitation inevitably turn it into as near a sphere as it'll get.
Given the time for transit, a space elevator would be used for transporting cargo to orbit. The life support requirements for carrying people for a week would be problematic.
it doesnt need to go all the way to the the station, but it would be beneficial as it would be close to the moon and reduce the fuel use needed to get there and come back. but they can build a "pod" that can handle that duration with current technology.
@@TheInsaneupsdriver The transfer to a spaceship has to occur at geostationary hight. At any other point the differential between the speed of the elevator and the orbital speed is too high to get a safe dock/undock.
"The life support requirements for carrying people for a week would be problematic" That hasn't been a problem for the international Space Station. The elevator wouldn't be the same size elevator car you currently take up and down within a building now days. We're talking anything up to the size of a cruseliner
@@DontScareTheFish The larger your elevator car, the larger and stronger your cable needs to be. Using Ryan's estimate of elevator speed of 300 km/sec and allowing for sufficient time for acceleration and deceleration, the transit time is about 6 days. You need to have capacity for life support for whatever number of passengers you carry plus the general cargo. The ISS is not an apples to apples comparison as the number of crew members on the station is small. If you only carry 3-4 people on each 6 day one way trip, might not be a huge problem. If you are carrying tons of cargo and 50-100 people as they did on the TV show, you need a really big elevator car.
@@pcuimac Depends on a planet's rotation rate, mass, and density. If it is small enough and rotating fast you could build a space elevator using rubber bands or braided grass.
To prevent an Earth cable catastrophe, how about this for an answer: -We send millions of robots to mine for materials at the asteroid belt. -Build Mars colony with Base, Observatory, Mining Factory, Space Elevator Factory, Space Ship Factory, Asteroid Robot Mining factory, and a terraforming Mars company. -Send asteroid belt materials to Mars. That way if any tragedy were to occur, it wouldn't happen on Earth, there's less gravity on Mars, so a space elevator probably wouldn't have to be as long.
Sometimes it's better to tell the truth. Carbon nanotubes, even boron nitride, don't come within an order of magnitude of the tensile strength needed for a surface-orbit structure on Earth. On Mars or the Moon, it _might_ be possible due lower gravity effects and shorter distances. And the idea that the collapse of such a structure would do minimal or no damage is.. optimistic. The amount of PE embodied in such a structure is immense, far greater than the sum of all nuclear weapons yet made, so there would be significant backlash.
Not sure why the speed would be limited to 300kmh, most of the journey is made in the vacuum of space so there is absolutely no speed limit until it reaches the atmosphere.
This video has made me think: Can space elevator be a game changer for delivering supplies from the surface of the Earth, when it is not that important the time it takes?
i think this scene is taken from Kim Stanley Robinsons Mars Trilogy, where a falling Sppace elevator cable wraps itself around the martian Equator (with much less atmosphere than on a habitable word).
You need to also consider electrical implications. The elevator would carry an enormous current down to Earth, emptying the ionosphere-Earth capacitor. How would that affect life on Earth?
Another great video. What do you think about Orbital Rings? To me they seem more achievable because they can be built with known materials. Mass production of grapheme and carbon nanotubes always seems to be 20 years away.
Great video on the general concept of space elevators, really enjoyed it. The other day, I've read about a concept of putting the counterweight/ "top floor" of the elevator another 38.000km away, making the center of gravity the midpoint of the whole structure - giving any outgoing spaceships one hell of a slingshot into deep space (minus the energy required to counter the corriolis effect, of course). Also, wouldn't a failing space elevator, busted near the top floor as shown in "Foundation", wrap severa times around Earth/ Trantor? God knows it'd be long enough? If I'd be building the damn thing, I'd orient my design on Arthur C. Clarke's design in "The Fountains of Paradise", using little more than cables (also doing dry runs on mars to get the engineering right might be a great idea, too). And when using carbon based nanotubes, I'd include some self- destruct charges along the cable to cut it into bits small enough so they'd definitely burn up upon re- entry. Which carbon is prone to do.
It's a balancing act. First off all we can't yet manufacture any length of carbon nanotube. It has to be flawless. Then you have a balance the elevator weight against the cable, knowing that requiring more strength means more cable weight, means more strength required. I hadn't even considered how long it would take. This turns the elevator into a ship with food, restrooms and sleeping quarters. It's quite possible it can never compete with rockets, especially if a two wat trip takes months.
Non-physicist / writer here, rate my idea: Build /half/ a space elevator with a huge staging area at the top, and then launch stuff via mass drivers and/or lighter than air balloons. Higher altitude means less air density, and a bit of decrease in gravity would make it much easier to get into orbit, correct? The structure could pull double duty as a powerplant, too, since it's of course going to have extremely high security anyway and built like a fortress at its base. To me this seems like a better idea than a traditional (read: vulnerable) space elevator, at least until the civilization has gotten around to building full orbital rings.
What you're describing is simply a tall building, not a space elevator. The difference is a tall building holds itself up off the ground with the structure in compression, while a proper space elevator is anchored down to the ground with the structure (cable) in tension.
Your right, I feel silly for the faulty nomenclature, but otherwise how would this idea stack up against the traditional space elevator design? I still envision it as much more robust of a deliver system to space.
Your idea would work if we stand it on its head! Build a space elevator, but start from the only place such a thing can start from... geostationary orbit. Once you have reached the tensile limit of your materials, you just let it dangle there, still thousands of kilometers above Earth surface. There is really no need to connect it all the way to Earth, indeed you would not want to, because its lower reaches would be imbeded in swarm of LEO satelites doing 24,000km/hr relative to it. To reach the bottom of the cable several thousand kilometers up I would suggest a series of skyhooks. These are like smaller versions of the geostationary orbiting cable you built, but as they orbit closer to the Earth they are going progressively faster around the planet. Instead of hanging vertically, these cables will be cartwheeling end over end. A spaceplane with electromagnetic grapple could climb these much like a flying trapeze acrobat. Grabbing on at the lowest point of its cartwheel and realeasing at the highest, to catch the next higher skyhook, and so on up and around the Earth orbits untill reaching the base of your hanging geostationary cable station.
If the journey to the orbiting station does take the better part of a month or even a week, you might quickly run into the problem of a significant part of the elevator car's mass being taken up by food and especially water for the human passengers. And you'd probably want to put a toilet, a shower, and some bunks in there too, further limiting passenger capacity. I would imagine with the travel times discussed in the video, space elevators would primarily be used for cargo, transporting raw materials and finished goods for space industry.
I'm not an expert, but the weight of the object at the top of the cable should make a significant difference on how it behaves when it starts to orbit freely. Also, after it is free to orbit, any internal friction that is created is being borrowed from the orbital potential energy, causing it to lose some of its orbital energy and altitude. Its endpoints will probably be busy whipping around and breaking off with enough energy to leave orbit and return to the ground. Your comment at 7:25 said "to minimize strain on the cable" seems wrong, because the strain on the cable is already enormous, and the extra strain caused by a moving vehicle along the cable is relatively zilch compared to the strain that's already there. Besides, there's probably no physical contact between the cable and the vehicle, since it's probably using electro-magnetism to keep them apart. Eg, MAGLEV. In any case, good clip. But I want more math.
Two things I noticed is that the counterweight station in foundation provides thrust while rotating, as if the plan was to weaken the cable and then twist snap it off. Also, the videogames halo 2 & 3, and Halo odst features a space elevator cable snap near the base and some of the aftermath. It's been 20 years so I don't recall what the exact scale of damage was in the game lore. And I think Halo also snapped another space elevator cable in a tie in movie. 😕
You would probably need some emergency disconnect on the planet side along with some backup propulsion systems built into the cable to yeet it into space if there ever is a failure
Even if huge portions of the space elevator cable were to burn up upon re-entry, I wouldn't categorise the resulting damage as minimal. Even if the cable impact isn't likely to cause canyons in the earths surface, surely the cable impact (or what little remains of it) would be capable of destroying many a skyscraper in its path (killing who knows how many, in the process), or worse should it hit power stations (as we are most likely to use nuclear power stations currently for an elevator) etc.
Even if the end might burn up on re-entry, there's still 30 or so miles of cable that was previously under huge tensile strength and now isn't. It'd be like a garrotte. Fortunately, we'd know what the elevator's trajectory would be (due east in Earth's case) and only zone parks or such in the immediate crash zone. It'd only have to be ~a city block wide given the relative size of the cable.
In the books Trantor had a population of 40Bn. The only reason the loss of life cause by the "Terror attack on the star bridge" would not be a statistical rounding error when compared with the typical birth and death rate is because of the politics involved.
great video. What are your thoughts on space elevator alternatives. Heinlein's The Moon is a Harsh Mistress describes what is essentially a large rail gun on top of a mountain to launch crafts into orbit. It seems like this idea would have many of the benefits of a space elevator but without the engineering complexity or risk of a large-scale catastrophe in the event of a failure.
Disney world has just opened a new "orbiting restaurant" that requires customers to board a space elevator to get up to it.... The simulation looks pretty cool as you get to see the earth recede away below as the station gets larger above. They even have the sound get quieter as the atmosphere gets thinner and thinner. You can see people's videos on UA-cam it does look pretty neat.Its called " Space 220"... I'd be curious to know what you think of their ideas.
Very fascinating. How long would the space elevator take to ascend if it takes 14 hours to descend? I am just imagining "The Girl From Ipanema" instrumental looped for 210 times while the space elevator takes 14 hours to descend.
If you actually made a space elevator, you would want two space stations. One being the counter weight as described here, and one being a station at geostationary orbit would allow you to launch spaceships to go to other locations - other orbits or other planets. Anywhere else and after you detach you would be at the wrong speed thus creating a very rapid acceleration. Although, I guess if you could build a space elevator, you could figure out how to detach at any point along it... Another interesting point not discussed, but I assume to be the case, if you are not at geostationary orbit I assume you would feel a force that would create a sensation of gravity.
Loved the video! Do you think going with an Orbital Ring as opposed to a Space Elevator would be easier? The ring can be made only a couple hundred KMs up, so the tethers only have to support that much weight as opposed to trying to stretch it up to geosync. The only downside is that once you reach the ring, you have no orbital velocity, so you have to expend energy to get up to speed. But at least there's no atmosphere anymore.
Just out of curiosity, what happens to the Cable at the base if a hurricane or other significant weather system hits it? To be sturdy enough to withstand a hurricane seems to argue against the necessary lightness of the Cable.
Oh, here's another problem... We don't know the size of Trantor compared to Earth, but given the sheer MASS of the space elevator in Foundation, I would believe not only that the center of mass of Trantor would be well OFF axis, but would even threaten to PULL the planet into an exotic orbit of its sun. Perhaps the rotation of Trantor would be somewhat erratic as the elevator daily pulled harder as it swung away from and then swung in the direction of planetary travel.
You've explained an incredible amount about the physics on a completed space elevator, however what I'm struggling to imagine is how one would be built to begin with. If you start from the ground and work your way up, if the cable isn't heavy enough it won't have the rigidity to build directly upwards. So instead do you have a spacestation at geostationary orbit first and build down, then extend the orbit slowly once it's connected? Again, then it would be traveling too slow at the point of connection and would collapse. So where do you start? If the latter is the solution, getting all the materials up there to build down seems like a waste as it would impose the original problem of leaving the atmosphere with rockets to build the initial cable.
You begin the build from geostationary, paying out cable both Earthward and anti-Earthward. If you were a smart astroengineering company, you first went out to the first likely size Carbonaceous Chondrite asteroid to source your carbon for nanotubes, instead of paying a gajillion Terran Cryptodubloons to source Carbon from the deep gravity well of Earth.
Would the tether really burn up in the atmosphere though, its relative velocity to the atmosphere would not generate enough braking force for that to happen as I see it?
The "end game" of a spacefaring civilization is not a space elevator i'd say. It's more like an orbital ring. maybe you could do a video on those along with some ideas on how they'd work, their practical applications and how you might construct one. Just a suggestion but I'd be interested in your take.
Probably a hybrid. An orbital ring with multiple tethers around the globe. The "problem" is that the ring is then also needing to support those tethers
@@DontScareTheFish Sure but I mean all orbital rings have/need tethers, otherwise, what's the point of them? As for supporting the tethers, easy, you just "overspin" the ring to a velocity greater than its orbital height usually dictates.
the mass effect music is a subtle touch and I love it lol
i love it, so fitting
I've read the foundation novels. The TV series is just vaguely similar. And by the way.. the god of YT (the algorithm) has noticed you. Go for it!
Sad but true.
I've read the books too and I think they've done a pretty good job given the circumstances.
You very well know it's an impossible book to convert into a movie. It's very heavy in political discourse and there are too many paragraphs where there are just a bunch of people sitting in a room talking. That doesn't make for good cinema.
@@dannybodros5180 so… why make it? Just for bucks? Isn’t a bad series. Just it’s not Foundation. They could just called it NGO….
@@PVilarnovo I'll answer your question with another question: why not make it? The more people that know about the series the better, even if it's just a TV adaptation. If anything, it could be their gateway into the books.
The Foundation series needs more recognition for its colossal contribution to science fiction.
Ideas such as hyperdrives, laser weapons and star wars were first envisioned in the series.
@@dannybodros5180 so… we will recognize the importance of Foundation with a series that has nothing to do with Foundation besides the name of the series and the name of some of the characters? Makes no sense.
The first scene of the underrated "Ad Astra" begins with an incident in an orbital elevator. And "The Fountains of Paradise by Arthur C. Clarke" is a classic about this theme.
This channel is criminally under-recommended by UA-cam. Another fantastic discussion on the depiction of physics concepts in sci-fi.
Thanks! Maybe one day I'll break through the great filter that is UA-cam's algorithm!
@@RyanRidden Worked for me 🤷🏻♂️ 😝
Do joined feature video with some scotsman living in US who also does space videos :)
Yeah so true, I noticed him because of some Scott Manley community post. I am glad I followed it
Agree. Also, I think it is time for Ryan to open up a Patreon 🧐
I am glad I found your channel. Was worth it for sure.
My first comment was also how underrated u are, I think Scott Manley brought me to you.
I'm glad you found your way here!
And I don´t remember the books ever mentioning a space elevator.
the first space elevator description I ever saw in a book was Fountains of Paradise, by Arthur C Clarke.
And then of course, the Mars Trilogy books.
Came here to say that. Glad it wasn't just my faulty memory.
The most significant damage was to my memory of the novel.
Great video. Liked and subscribed.
im very grateful to youtube algorithm to suggest me your channel..excellent content
Imagine one month of banter in Mass Effect‘s elevator 😂
Great video and many thanks for the explanations!
Garrus would find a way to do calibrations for a month!
@@RyanRidden Mass Effect reference earned you a subscriber!
I’m glad I stumbled across this channel,
I’ve been fascinated with the idea of a space elevator since reading about one in the Mars trilogy by Kim Stanley Robinson, and I’m glad they put one in Foundation, I’m sure Asimov himself would have considered the idea too much when he was writing them originally, he admitted as much before he died too… it fits for this story.
Great video!
I remember a similar scenario in Red Mars by Kim Stanley Robinson with another space elevator built, then sabotaged above Mars. It's been years since I read it, but I vaguely remember there being equally dramatic results. Like one of the scenarios you mentioned, the book used an asteroid as the station/orbital end to provide the required mass to keep the cable taut.
Due to the transit times it seems like a realistic space elevator would be more useful for cargo and bulk materials than passengers.
Thanks! I still need to read Red Mars, it seems like a really good book! I think you're right, space elevators would be ideal for moving non time critical stuff around. I'm not sure too many people would want to spend a month to commute into space!
Transit times are on par with long distance travel in the modern world. And both are vastly faster than travel in the past. Just because a rocket will do it in a few minutes doesn't mean a few hours is unbearable.
Due to Mars' lower mass, the cable isn't as long as what would be needed by Earth, and also due to Mars' much thinner atmosphere, the cable didn't burn up on the way down, and it was still long enough to wrap around the planet a couple times.
@@tonygoinggonzo Also IIRC it was tethered to one of Mars' tiny, porous moons and the weight of the cable brought it down. If I've remembered this wrong please tell me and I'll go and write my own space opera :)
@@GavinMorris1 it was tethered to and built using materiel from a captured asteroid. during the same war they blew up one of the moons, but I can't remember if it was Deimos or Phobos? when they rebuilt the elevator, they used another captured asteroid
Suggestion: You wrap the cable in superconductive wire and put a few hundred amps through it. In case the cable were broken the strong magnetic field would bring the ends of the cable together again so it wouldn’t fall. OK, you’d have to go up and actually strengthen the cable again at the break point but you wouldn’t have to start from scratch again. As the magnetic flux lines are parallel to the direction that the transporter chamber would take when transporting people and freight to and from orbit, it wouldn’t apply any extra force on them, and would only be a problem with it’s interaction with the earths magnetic field which would cause the cable to tilt towards the pole. Actually that could make the cable a little shorter.
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Would bring a lot of complexity to the system and in 99.99% of the cases whatever broke the actual cable (which is ridiculously strong) would also break the wrapping wire.
@@ItsMySpaceship You're right about the complexity, but on reflection, you wouldn't need to use wire, you can use a sheath, like shielded wire, and have the current just flowing inside the shielding. The shielding can also be extreamly thin, sub-micron. OK, granted you would need to use a high temperature superconductor. But there is some evidence that carbon nanotubes could be strong enough to form the backbone of the cable, and also some evidence that nanotubes are superconductive under certain circumstances. Maybe we can circulate a current through the cable itself and so produce a strong enough magnetic field to pull the broken ends together again. I know all this is speculation about things that we don't yet know how to make, but it's still fin to play at "what if...".
@@martinstent5339 Why would there be a magnetic field if the superconductor is severed? Current flow would also be severed, so no field would be created.
@@TheHalcyonTwilight because the current is going AROUND the wire, and not along the wire. It means you need an insulating core in the centre of the supercunductive wire, but that only needs top be a few molecules thick. The current going around the wire creates a magnetic field along the wire lengthways and can't be stopped by breaking the wire, so if the wire gets broken you will immediately get a north and south pole very near each other and they will pull back together.
Fascinating and informative. I remember reading Arthur C Clarke's novel featuring space elevators (Fountains of Paradise) and being intrigued by the whole idea so its good to see the science behind such a construction so well laid out. Thank you.
I've read quite a few of his novels, but I haven't read that one. I'll need to check it out!
No. The whole video is pure nonsense.
@@RyanRidden It's a great book.
They’ve got magic artificial gravity on the space ships. This technology would allow them to make the cable extra girthy.
If the have anti-gravity there is no point in the elevator at all. Extra gravity is not helping in this case.
@@stefanr8232 they do have anti gravity. It obviously wouldn’t be used to increase the gravity, it would be used to counteract it. Anti gravity implies advanced active suspension. You could make it so that there’s no stress on the cable. Yes obviously that tech would make the elevator pointless especially since they have the only space elevator and presumably the thousands of other planets get by just fine without them. Also they’d need to use some sort of active gravity since their ships are capable of containing Planetary mass black holes without ripping themselves apart.
@@stefanr8232 I would assume anti gravity is energy consuming, theres a reason we send so much freight by slow ships rather than hovercraft, even though we have the tech its not economical to use it in all cases.
Magic would really help with all the engineering problems of an Earth space elevator. Magically producing a million tons of cable of supersophisticated materials. Magically getting elevators to be able to crawl up it. Magically damping vibrations. Magically healing radiation and micrometeorite damage. Magically eliminating electromagnetic effects along thousands of kilometres of cable. Most people and trades that want to travel in space would just get out of deep gravity wells and stay on nice little rocks.
@@bigdopamine9343you need antigravity to get the right force profile in the cable. You can't get it right with just tension.
Literally just found your channel, you're a godsent my dude. Gorgeous video and explanation! Earned a fan, you have!
Thanks a lot for this very informative video!!
I once calculated the forces on an elevator to geosynchronous orbit and found that no material could support the weight of just the string itself
Only applies to geosynchronous. Need to recalculate for trantosynchronous. Need the number of seconds in a day, the acceleration of gravity at the surface, and the surface escape velocity (or radius). Luna is low enough gravity the elevator could be made out of materials currently on the market. For Haumea the elevator is so easy we could almost build it as a tower under compression but not quite. Mild steel or cotton is easily strong enough for Haumea under tension. On Phobos we could do it with corrugate boxes and stretch wrap and it would support itself with both compression and tension.
@@stefanr8232 fair enough, my calculation was for a story set on Earth
There is no currently available materials, however the tensile strength of carbon nanotubes is suppose to have a sufficient margin. The problem is a) it would need to be a continuous (perfect) nanotube, b) we cannot make the stuff in sufficient quantity or quality
@@DontScareTheFish Also c) you would need a large taper ratio A straight single tube would not be able to do it. It would be much wider at the top.
The elevator’s string is intended to be self supporting, ie: pushing up by an active support system
RIP string :(
Thanks for making me aware of another cool show.
Sometimes science requires sacrifices
@@RyanRidden It's just Foundation, not 'The' Foundation
When you describe what happens to the top of the elevator once the tether is severed, you said it would simply rise to a higher orbit. Actually, the top of the elevator would simply enter an eccentric orbit instead. Before the tether is severed, the entire elevator is orbiting the Earth its center of mass, in a circular orbit defined by the length of the tether. Once the tether is severed the two parts now each have their own center of mass. The topmost part is traveling too fast for the orbit it was previously in and would act like a spacecraft firing its engines directly downward toward the Earth, accelerating instantly outward. This would push it into an elliptical orbit were it would continue to lose velocity until it reached its aphelion, at which it would start to fall inward toward the Earth, gaining velocity until it reached its perihelion, where it would be traveling too fast to be pulled all the way back to Earth and be flung outward again. This is similar, to a Hohmann Transfer maneuver, it which a spacecraft in a lower orbit needs to rendezvous with another in a higher orbit. One thrust burn puts it into an eccentric orbit going outward. Another burn is needed to make its orbit circular again.
In the show the severed elevator station does fall back to Earth years later but is detonated into debris before it hits the atmosphere to avoid a great impact.
Didn't see your comment before I post my own, arguing the same point. One correction to your is that Aphelion only applies to solar orbits. Apoapsis is the generic term and Apogee is in Earth's SOI. As I stated in the other comment, the proper terms for Trantor's SOI are probably Apotor and Peritor.
@@2nd3rd1st The station should NOT fall back to earth (lower case E). The lowest point in it's new orbit should be the altitude it's new center of mass was at when the cable snapped.
@@Corbald But the orbit would decay slowly, and in the show considerable time passes between the elevator getting free from Trantor and Empire finally making the call to demolish the remains.
@@cheytacsnipes Yes, but not that quickly. Most of the orbital decay experienced by artificial satellites in Earth's orbit is caused by interactions with our atmosphere. While it gets very thin, our atmosphere extends nearly to the moon! Even still, objects in _geostationary_ orbit (or beyond, as the platform would have to be) experience _very little_ orbital decay. It would take _centuries_ for it to decay enough to pose a threat to the planet.
An example of this is that there are still fuel tanks in orbit of the Earth from the Apollo era, and the Apollo 11 lunar module is likely still in orbit around the moon.
I never understood why geostationary orbit works before this. Thanks
I've been watching tons of Space Elevator stuff recently and Issac Arthur has a great channel where he covers all sorts of science and sci-fi stuff (shameless plug for his channel here).
One idea that he mentions is that the station at the top could be attached by more than one cable. This would not only provide stability (fasten anything with three different guide ropes as an example), but the other cables would act as the buffer if one were damaged or destroyed. At a high enough orbit the station could be powered by the sun and it could even become a solar power station, sending surplus power back to Earth.
As for the 'wrap around' effect from a falling cable cut high in orbit, it would take a lot of explaining to convince me that the result wouldn't be a horror show that would make 9/11 look like a fender-bender. Even if the cable weren't very heavy, it would still be traveling at terrifying speed both because of gravity pulling it down AND the rotation of the planet winding it up like a string around a yoyo.
Great video. I had wondered about which elements of the space elevator worked and which might not. Your explanation about the forces involved, the orbital speeds, and how where the break occurred (as well as the likely mass of such a structure) impacts the aftermath were enlightening. The engineering behind how to actually create such a thing must be astounding.
Nice MASS EFFECT PRESIDIUM MUSIC !
Bruhh there vision of the warp drive was🔥🔥🔥
6:29 - You're counting the total distance to the counterweight, though. The actual space station could be half way along the cable (in fact, there could be multiple stations at different altitudes).
The station in the show must be the counterweight, though, so he is doing the calculations correctly for this situation
@@CharlieQuartz - The one in the show does several physically impossible things; the example he was giving was an attempt to get (the main part of) the physics right.
He even correctly called that mass "the counterweight" (not "the station"), but then measured the distance to it and apparently forgot that there could be a station (or several stations) at different altitudes.
There is a better option that will make space elevator as a children's toy it's called ORBITAL RING and no magic material needed much higher throughput
An orbital ring doesn't get you to orbit though. You try to step off into the void and you fall back to earth instantly.
You gain altitude and you get out of the atmosphere, but to reach orbit or leave to another place in space you still need something like a rocket to gain delta and get there.
You are still under something like 90% nominal earth gravity, to get to orbit at the altitude you are already at you still need most of the fuel mass you would have needed if you launched from the surface.
@@DrewLSsix true but u can use a simple linear accelerator and as u are in vacuum u can reach orbital speeds easily and dude to size u have more than enough length to do it
Excellent use of Mass Effect music 😍
Mass Effect has an incredible sound track!
I believe that once we have the infrastructure to build such an object, we will no longer need such an object. Also, the tether may not do much damage, but what about all the elevator pods/carts with people or cargo on them? In order to make these economical, you would need a lot of traffic going up and down at the same time and each one would probably be much denser than the cable. Also, a space elevator is not more efficient. It requires the same amount of energy to reach a particular orbit for a specific amount of mass. It just matters where you get the energy. Today a chemical solution does seem much more expensive (although a lot quicker), but don't forget that your object has to reach the top and then burn some fuel to adjust its intended orbit or escape velocity. Also, don't forget the fuel will need to be used to help with station keeping. That heavy counterweight will need some pretty nice RCS thrusters as the orbit will never truly be stable, especially when you consider all the forces acting on the cable and the dynamic amount of mass entering and leaving earth through the cable/station changes the center of mass. There are a lot of problems. These problems are/should be solvable. But just because they are solvable doesn't mean the solution will be practical. I am willing to bet that once we have confidence in building such a system, we would also no longer need to build it. But then again... who knows.
Nonsense. First of all, it isn't about whether you NEED it. It's about the expense it would save. If you could DO something but it cost a thousand times as much to do it one way as another, would you not do it the cheaper way because you don't "need" it?
And yes, it IS much more efficient, and you need MUCH LESS fuel, because you don't need to lift the weight of the fuel, and the extra fuel needed to lift the extra fuel, and the extra fuel needed to lift the extra fuel needed to lift the extra fuel, which is the problem you face with using rockets. The rocket equation is an exponential function for this reason. If you had a space elevator, you could have the thing POWERED by an electrical station ON THE GROUND. That is why it would be much more efficient. You really don't know what you're talking about. You know what they say, it's better to keep your mouth shut and worry about the world thinking you're a fool, than to open it and remove all doubt.
The thing is I agree with your pointsd 100%, but keep in mind for many of these exact reasons the space elevator makes a great 'make work' project and show of empirial 'greatness'. It's kind of an Arch of St.Louis thing.
but having such a thing would save so much energy you would otherwise need to produce the chemical fuel aswell as saving the energy said fuel would waste in heat while being burned. you could power it electricaly, which is much more efficient then chemically, via a giant solar farm or even a nuclear power plant. once it is set up, you wouldn't need as much energy as you'd need with a rocket because you don't need to waste it anymore to fly around the earth fast to get into that orbit, you can just go straight up.
having such a thing set up, could be a turning point for a young space fairing race. think about the possibilities, you could even have a little shipyard as the counter weight station and start building spacecraft in space. you could just send all the ressources and materials up with the elevator. wanna have a satelite in orbit, no need for big fucking rockets anymore, just build the satelite there and launch it without a launch vehicle. wanna send one of elons starships to mars, no need for the super heavy booster, just build the ship there and send it to mars.
of course there is so much stuff to consider with these things but still, having the technology and the ressources to build this new infrastructure and not do it would be very stupid.
@@Rekcoj Firstly I did have a response to earlier comments that, for some reason, got deleted or was never posted that did bring some of this up... not sure what happened to it.
1) "but having such a thing would save so much energy you would otherwise need to produce the chemical fuel":
Ok sorta. The 'economy of scale' will undoubtedly reduce the price of fuel significantly. So while a space elevator would use theoretically zero how much are you saving? And what are you gaining/losing? Do not get so hung up on an advantage, for there are always disadvantages. In our history, we have invented many technically better things that never got used simply because of some other unaccounted for disadvantage.
2) "you don't need to waste it anymore to fly around the earth fast to get into that orbit, you can just go straight up.":
What about objects or people who wanna leave orbit? Want a lower orbit? Not every satellite will want the same orbit. Also, the energy provided to the cargo by the time it reaches the orbiting station is not enough for the mass to achieve circular orbit. It will need its own propulsion and fuel to leave the station and circularize its orbit. The station itself will have to have station-keeping thrusters that also burn fuel. It is nowhere near the same amount as the current rocket launch, but the point is that a Space elevator doesn't completely remove the need for fuel.
3) "think about the possibilities":
This is not an argument for space elevators. All space elevators do in theory is provide reliable and cheap access to space. The possibilities can come from any technology that sufficiently provides reliable and cheap access to space. This argument would only be valid if space elevators were their only option. And it simply is not.
4) "and not do it would be very stupid."
Humans have done this very thing countless times in our past. Sometimes it is seen as short-sighted/stupid while others times it was clear why. My main argument is the 'chicken and the egg' situation. That once we have the technology, confidence, and infrastructure to build a space elevator, we wouldn't need one. Because a Space Elevator is a megaproject that would first require technology, confidence, and infrastructure that provides reliable and cheap access to space.
----
Also, cheap!? Really!? The unsung hero of space flight is the launch pad. Easily more expensive to build than most rockets, and it is costly to maintain as well. The prep before and after each launch isn't talked about because it's boring. It's all about the rocket. But it is easily the second most expensive part of launching a rocket. You wanna make a product that probably costs 1000X as much as a launchpad to not only build but to maintain as well, and then claim its gonna make space cheaper!? Really? Why because it doesn't burn fuel? Fuel is one of the cheapest parts of space flight. And again, as the production of a newly in-demand product increases, its price usually drops significantly. Going forward, fuel is gonna be even cheaper, and it already isn't a serious concern.
Lastly, if we believe we can achieve something like a space elevator in the future, then what about all the other future tech that is possible. Single Stage to Orbit reusable craft? In-takes that liquify oxygen as it passes through the air to 'breath' so you don't have to have all the fuel on launch? Hyper-Sonic plans. All of these things are possible and have been or are being researched. And that is just what could come out in the next decade or so. What about 50 years a 100? A nation like USA would likely push for that before letting some country on the equator control 'cheap' access to space.
Would definitely recommend 'The Space Elevator' by Dr Bradley C. Edwards. Great read, spends a lot of time on the physics, logistics and economics of elevators. All we need is a CNT ribbon that can self support about 30 000 tons and is about 50,000 miles long ...he didn't say it would be easy :)
Try 'The Fountains of Paradise' by Arhtur C Clarke
In episode 3 of Foundation, many years after the attack, the Empire brothers discuss what to do with counterweight that is orbiting the planet.
The counterweight is orbiting, as you expected.
The brothers also decide to Nuke it instead of rebuilding it....
Which makes no sense whatsoever because you can use it again and another question is it's been 30 years...why hasn't it been rebuilt...?
@@Shinzon23 Because the empire is broke
@@nicolas.p331 no indication given of any sort of economic issue.
@@Shinzon23 Unless you count the derelict space station.
@@Shinzon23 That's an indicator of how the empire has decayed. It's one of the main points that were predicted by psychohistory (at least in the books and yes I know they didn't have the elevator).
Thanks for mentioning coriolis force. I always wondered if it would be manageable.
I love how it takes less than the length of the video for commenters to come up with the solutions that the empires greatest engineers somehow failed to foresee over their lifetime of designing and building the elevator. Anyway, it does not matter how the elevator broke in the story, its used as a plot piece to show that the empire is not infallible and leads to public doubt in the empire sowing the seeds for the future.
Thx for the video!
Examining the Coriolis effect would be interesting. If you can, please cover it. Also, all information gets stored. Storage is cheap.
thankyou for introducing me to this series :)
The math is down cold, all that remains is the materials science.
Back here on Sol, rather than Trantor, space elevators for Mars are more easily achievable than for Earth. About the same rotation, but lower gravity, translates to less strength needed for the cable. Not sure whether you can keep Phobos around with a space elevator. Might need to use a sky hook with Phobos as the pivot.
I gotta say, people seem to REALLY forget about the kind of voltage and current levels we are dealing with when we are talking about making an object that is going from the ground out beyond the magnetosphere. If you have ever seen the footage of NASA's tether experiment in low orbit, the crazy plasma formations produced would give you a good idea of what is going to happen to any space elevator type object. It's not just a matter of tensile strength, you're talking about trying to handle insane amounts of charge in an optimal situation much less trying to deal with large solar flares.
At first, the lower part of the cable would fall slowly, but the upper part would snap like a whip at hypersonic speed. It would send a huge continuous shock wave around the globe as it enters the atmosphere (like when the asteroid exploded over Cheliabinsk) and if it reaches the ground, you would face way more destruction...
I think Foundation got it right. You can't treat as a point mass because the elevator size is large compared to the size of the Earth.
Any parts of the elevator out to 80% of geostationary orbit will crash into the Earth over about 4 hours. The final pieces will hit the Earth at about 10 km/sec. It won't be pretty.
When it hits the Earth, it will be shorter by about 20%. Even if it's in one piece when it starts, it will tear itself apart as it falls.
Things from 80% to about 150% will go into orbit around the Earth. After that it's iffy.
They showed an exceptional example of how it would fall.
Robert Forward has done some interesting speculation (with an eye to the physics!) about the space elevator and several variants not requiring any geostationary orbiting.
[ interesting point, some of his designs are chain-drive! ]
The welcome UA-cam algorithms strike again. Dr Ryan, you are my kind of nerd.
Tbh, I don't think a space elevator should be the endgame but relatively early in a space faring civilization. That way our ships, depending on their purpose, don't have to consider taking off from the planet but can be built in orbit.
You can build the in orbit right now if you so wanted - you just need to get resources from space (other objects with low gravity well - asteroids, moons...) instead from Earth.
You will always have a problem of going to orbit from a planet.
But there are two approaches. One is to build an entire ship on surface, then launch. That is a huge waste.
The other is to have large ships in orbit and some system to just facilitate surface-orbit transfer. And, in fact, that is what Space Shuttle was originally designed to be.
It was supposed to be a truck that would transfer people and what not to orbit, and then other craft up there, nuclear powered, would take over. It was supposed to be a two stage system.
So the thing you've said - it was actually planned. Just not with an elevator but multi-use rockets instead.
And the end game for a civilization is a ship like Millennium Falcon - one that does not care where it goes, it is the same to it. Is such a thing even possible - who knows. But that is the end game concept for space travel :)
Elevators are simply not that practical. A lot of resources spend, and one damn huge target. Not to mention that is one accident away from global disaster. Earth is showered by meteorites all the time... and you'd have a gigantic piece of infrastructure that has to endure everything that humanity and space can throw at it... for several centuries... in order to pay itself off? I am not holding my breath.
That scene reminded me of the book "Red Mars" where a similar event happened to a martian space elevator.
Kim Stanley Robinson is a brilliant writer. Profound incite into human behavior. Unparalleled ability at describing scenes. He is not a physicist though. He actually makes fun of a few errors in later books. I recommend reading both the Mars trilogy and later publications. I would not use them as orbital physics reference.
@@stefanr8232 I have only read Red Mars of all of his books so far. Got sidetracked from the rest of the series by other books from other authors a while ago and the profuse profanity and sexuality makes me hesitate to return even though I very much enjoyed the story. Call me a prude, but I wasn't raised that way and so such elements didn't add to the story, only distracted me. I have the same problem with Tom Clancy.
They should start with a moon prototype and test orbital compensation techniques. Work on a 140km rubber ducky building, 5km long 2km under water with a hyperloop
The moon’s gravity is very low, so there aren’t any real benefits to making an elevator
One thing missing here is that space elevators were not a new concept created by the writers of this TV Series. The Foundation series was of course originally written by Isaac Asimov and published from 1942 onward. Additionally, Arthur C. Clarke's and Charles Sheffield's (both published in 1979) are generally considered to be the works that introduced space elevators to the science fiction community at large.
If you pay attention during the Halo 3 ODST Mission on at the Zoo, when they pass and one of them makes a comment about the Space Elevator snapping. You can see the Elevator cord in the middle shoot up into the sky as its support rings fall down.
Relatively simple to do. The biggest issue is what Foundation has had to deal with. Build something that big and you're painting a target on it.
In Kim Stanley Robinson's trilogy about the terraforming of Mars, one of the books -- I think it's late in the first book, "Red Mars," a space elevator is sabotaged and there's quite a good description of what happens on the ground as a massive cable long enough to reach high orbit comes crashing down & wrapping itself around the planet. (If it's not in Red Mars, then it's in one of the sequels: Green Mars, or Blue Mars -- I recommend them all for anyone interested in "hard" SF.)
Thanks for informing me there is a Foundation TV series.
I didn't know!
I have read EVERY one of the Robot. Empire and Foundation books. Including all the "connecting" like
I'm very sad to say if you enjoyed the foundation books then you probably won't like the Foundation TV series. The apple TV series should have a "Adapted for TV from the Foundation Series by Isaac Asimov" disclaimer.
@@DontScareTheFish yeah.
Watched them so far.
Good sci-fi but not really like the books.
So I had an idea on how to possibly get space elevators ''soon''.
Stage 1: Copy the movie Geostorm and create a net around the world in which there are satellites to control weather phenomena to prevent natural disasters.
Stage 2: Start the construction of a frame on the net around the world creating part/s of the basic frame of a ring world.
Stage 3: Build space elevators up to the frame.
With this we can transport materials directly into space without rockets much earlier, meaning less wasted resources. The distance will be nowhere near as far as a traditional space elevator meaning less transport time while if made of the right materials the frame will be able to support it? Not only can we create multiple space elevators for the cost that just 1 traditional would have cost but we can build shipyards on the frame and so many other things. Not only that but stage 1 is also essentially a prototype terraforming system, meaning we could learn all kinds of things for when we start to colonize other planets.
I am by no means an expert, this is just an idea I got out of nowhere.
Thought I heard Mass Effect music 👌🏻
Some of the stuff I see in the tv series I recognise in books by...Arthur C. Clarke. He too posited that it would be more practical to build on on Mars. The trick would be to tune the bean stalk so it would bow allowing Phobos and Deimos to pass safely. In terms of energy consumption, as with conventional elevators you have a counter-balancing compartment at the other end of the cable. As one ascends the other descends. The challenges of a beanstalk on Earth are described in his novel Fountains of Paradise.
Great video! What about a Orbital ring?
The question is when you have spacecraft that have some kind of anti-gravity that lets them land and take off from planets directly, what do you need a space elevator for?
11:00 make the cable thick enough for massive traffic and even a low density material will have a high enough mass to surface area ratio to carry its momentum through the atmosphere.
More feasible to build are orbital rings, tethered rings, and launch loops.
hmmm, you forgot something, the elevator would short circuit the ground to the solar wind. there would be a massive flow of energy from the van-alan belts to the ground, normally we see this as Aurora and red and blue sprites above dense cloud formations. such a structure could create a pretty spectacular light show and cause, some interesting ground voltage, EMF/RFi effects at the point of ground contact.
An interesting point. You could potentially use the space elevator as a power generator then, of a type never before seen.
Very fine.
A method to mitigate the damage that a severed falling cable would cause would be to detect the point where the break had occurred and at that moment sever the rest of the cable up into much smaller links where each link would settle into a slightly lower orbit. They could eventually be rejoined from the top down as long as the links had been designed with contingency thrusters to maneuver them back into place. There are still other ways to space now possible without requiring rockets or super long singular space cables. Think tethered concentric orbital rings. That’s where all the plastics/co2/carbon fossil fuels should be going to - raw carbon based construction material - we will need a crazy amount to pull it off.
Great video as usual! I actually thought space elevators are very dangerous and can cause catastrophic damage but you clarified that pretty well. The fall of new mombasa elevator in Halo 3 was awful guess thats what made me think they were dangerous lol.
And I think why we cant make space elevators probably is not because they are not scientifically possible as you said, but rather that its not possible production and economics wise. Even if we find the perfect material that fulfills all requirements, imagine how much of a challenge it is to produce 40,000KM of that stuff. And not to speak how expensive it will be. It will a massive and unrealistic undertaking for a single superpower like USA and will porbably require a multi national consortium and thats where politics will come. Even if we figure out science, it'll take a very long time to figure out the economics and politics to make it possible.
I think Halo 2/3 was the first time I saw a space elevator, and it certainly left a lasting impression on me as well!
Space elevators would certainly require a very stable political climate. It's quite easy to imagine scenarios where control of the elevators controls the world in some way. Hopefully humanity will work out the social and technical issues of elevators sometime soon!
The space elevator is destroyed in the opening cut scene of halo ODST / the end of the 3rd or 4th human mission of halo 2.
However, the elevator is severed at skyscraper hight when the ship enters ftl. So most of the elevator should have floated off into space right?
The car can go really fast while out of the atmosphere and slow down a lot when entering it and vice versa
The issues I have with Space elevators are:
1. Everyone talks about when it is operating, but no one explains how you would build such a space elevator… perhaps you can explain how such an elevator can be constructed… do you pay out the cable from space to ground, or take the cable from ground to space… as an engineer… I am not interested in ‘well it just get made..”… I am interested in practical solutions… perhaps you should do a video on that would show your mettle…
2. You need to take into account the atmospheric drag the cable would have, because such a wide cable going through the atmosphere will have a considerable wind loading pressure and force applied to it
3. Electrical potential voltage across the cable.. especially in space. This is because of the experience from the application of space tethers on the space shuttle that were cut because the high voltage difference and high current through it burned out the space tether. This voltage can be induced by cutting the lines of earth’s magnetic field, and the charge particles coming from the sun, and at 40 000 km in length will this space elevator be in the Van Allen belt?
Seems like Red Mars had a relatively realistic approach. Kick one of Mars' moons to areostationary orbit, use automated machines to convert its material into the tether material and use the remaining mass as the 'anchor' and space station. Seems like the real trick is inventing a tether material that's strong enough to resist all the forces you've mentioned as well as micrometeorite and debris strikes and other dangers, while still be light enough to not just collapse under its own weight within the higher gravity regions closer to the surface.
Correction: I think they used a captured comet injected into mars orbit, since the higher carbon content of the comet made it useful for manufacturing massive amounts of carbon fiber.
I mean maybe they discovered stronger materials in the future, which could enable such big and heavy cables. The station is pretty huge.
More accurately, the orbital platform wouldn't raise it's _entire_ orbit, just the Apoapsis, with the (new) Periapsis being at the point in it's orbit where the cable was severed.
Apotor? Peritor? Dibs on naming credit!
Also: If the cable snaps near the base, it would begin to spin in it's orbit, around it's new center of mass, until it coils up. Initially it'd resemble a sky-hook, until it's orbital dynamics and self-gravitation inevitably turn it into as near a sphere as it'll get.
Given the time for transit, a space elevator would be used for transporting cargo to orbit. The life support requirements for carrying people for a week would be problematic.
it doesnt need to go all the way to the the station, but it would be beneficial as it would be close to the moon and reduce the fuel use needed to get there and come back. but they can build a "pod" that can handle that duration with current technology.
@@TheInsaneupsdriver The transfer to a spaceship has to occur at geostationary hight. At any other point the differential between the speed of the elevator and the orbital speed is too high to get a safe dock/undock.
"The life support requirements for carrying people for a week would be problematic" That hasn't been a problem for the international Space Station. The elevator wouldn't be the same size elevator car you currently take up and down within a building now days. We're talking anything up to the size of a cruseliner
@@DontScareTheFish The larger your elevator car, the larger and stronger your cable needs to be. Using Ryan's estimate of elevator speed of 300 km/sec and allowing for sufficient time for acceleration and deceleration, the transit time is about 6 days. You need to have capacity for life support for whatever number of passengers you carry plus the general cargo. The ISS is not an apples to apples comparison as the number of crew members on the station is small. If you only carry 3-4 people on each 6 day one way trip, might not be a huge problem. If you are carrying tons of cargo and 50-100 people as they did on the TV show, you need a really big elevator car.
Nice KSP music for elevator. LOL
I've always wondered the possibilities of building one of these science fiction marvels
They would certainly be hard to build, but they would look pretty amazing!
They are not possible. The forces are higher than ANY chemical or physical bond between atoms.
@@pcuimac Depends on a planet's rotation rate, mass, and density. If it is small enough and rotating fast you could build a space elevator using rubber bands or braided grass.
To prevent an Earth cable catastrophe, how about this for an answer:
-We send millions of robots to mine for materials at the asteroid belt.
-Build Mars colony with Base, Observatory, Mining Factory, Space Elevator Factory, Space Ship Factory, Asteroid Robot Mining factory, and a terraforming Mars company.
-Send asteroid belt materials to Mars.
That way if any tragedy were to occur, it wouldn't happen on Earth, there's less gravity on Mars, so a space elevator probably wouldn't have to be as long.
I've dreamt about space elevators ever since reading Kim Stanley Robinson's Mars Trilogy.
Sometimes it's better to tell the truth. Carbon nanotubes, even boron nitride, don't come within an order of magnitude of the tensile strength needed for a surface-orbit structure on Earth. On Mars or the Moon, it _might_ be possible due lower gravity effects and shorter distances. And the idea that the collapse of such a structure would do minimal or no damage is.. optimistic. The amount of PE embodied in such a structure is immense, far greater than the sum of all nuclear weapons yet made, so there would be significant backlash.
Not sure why the speed would be limited to 300kmh, most of the journey is made in the vacuum of space so there is absolutely no speed limit until it reaches the atmosphere.
You have forces applied to the cable from the thing moving... even in space
In the novels, the Encyclopedia was a ruse to get people to go to Terminus.
Like the Mass Effect music
This video has made me think:
Can space elevator be a game changer for delivering supplies from the surface of the Earth, when it is not that important the time it takes?
i think this scene is taken from Kim Stanley Robinsons Mars Trilogy, where a falling Sppace elevator cable wraps itself around the martian Equator (with much less atmosphere than on a habitable word).
Mass Effect!!!!
You need to also consider electrical implications. The elevator would carry an enormous current down to Earth, emptying the ionosphere-Earth capacitor. How would that affect life on Earth?
Another great video. What do you think about Orbital Rings? To me they seem more achievable because they can be built with known materials. Mass production of grapheme and carbon nanotubes always seems to be 20 years away.
Great video on the general concept of space elevators, really enjoyed it.
The other day, I've read about a concept of putting the counterweight/ "top floor" of the elevator another 38.000km away, making the center of gravity the midpoint of the whole structure - giving any outgoing spaceships one hell of a slingshot into deep space (minus the energy required to counter the corriolis effect, of course).
Also, wouldn't a failing space elevator, busted near the top floor as shown in "Foundation", wrap severa times around Earth/ Trantor? God knows it'd be long enough?
If I'd be building the damn thing, I'd orient my design on Arthur C. Clarke's design in "The Fountains of Paradise", using little more than cables (also doing dry runs on mars to get the engineering right might be a great idea, too).
And when using carbon based nanotubes, I'd include some self- destruct charges along the cable to cut it into bits small enough so they'd definitely burn up upon re- entry. Which carbon is prone to do.
It's a balancing act. First off all we can't yet manufacture any length of carbon nanotube. It has to be flawless. Then you have a balance the elevator weight against the cable, knowing that requiring more strength means more cable weight, means more strength required. I hadn't even considered how long it would take. This turns the elevator into a ship with food, restrooms and sleeping quarters. It's quite possible it can never compete with rockets, especially if a two wat trip takes months.
Not a science guy but i " THINK " i understood everything you said " GREAT " job
Glad it made sense!
Non-physicist / writer here, rate my idea: Build /half/ a space elevator with a huge staging area at the top, and then launch stuff via mass drivers and/or lighter than air balloons. Higher altitude means less air density, and a bit of decrease in gravity would make it much easier to get into orbit, correct? The structure could pull double duty as a powerplant, too, since it's of course going to have extremely high security anyway and built like a fortress at its base. To me this seems like a better idea than a traditional (read: vulnerable) space elevator, at least until the civilization has gotten around to building full orbital rings.
What you're describing is simply a tall building, not a space elevator. The difference is a tall building holds itself up off the ground with the structure in compression, while a proper space elevator is anchored down to the ground with the structure (cable) in tension.
Your right, I feel silly for the faulty nomenclature, but otherwise how would this idea stack up against the traditional space elevator design? I still envision it as much more robust of a deliver system to space.
Your idea would work if we stand it on its head!
Build a space elevator, but start from the only place such a thing can start from... geostationary orbit.
Once you have reached the tensile limit of your materials, you just let it dangle there, still thousands of kilometers above Earth surface.
There is really no need to connect it all the way to Earth, indeed you would not want to, because its lower reaches would be imbeded in swarm of LEO satelites doing 24,000km/hr relative to it. To reach the bottom of the cable several thousand kilometers up I would suggest a series of skyhooks. These are like smaller versions of the geostationary orbiting cable you built, but as they orbit closer to the Earth they are going progressively faster around the planet. Instead of hanging vertically, these cables will be cartwheeling end over end. A spaceplane with electromagnetic grapple could climb these much like a flying trapeze acrobat. Grabbing on at the lowest point of its cartwheel and realeasing at the highest, to catch the next higher skyhook, and so on up and around the Earth orbits untill reaching the base of your hanging geostationary cable station.
If the journey to the orbiting station does take the better part of a month or even a week, you might quickly run into the problem of a significant part of the elevator car's mass being taken up by food and especially water for the human passengers. And you'd probably want to put a toilet, a shower, and some bunks in there too, further limiting passenger capacity. I would imagine with the travel times discussed in the video, space elevators would primarily be used for cargo, transporting raw materials and finished goods for space industry.
I'm not an expert, but the weight of the object at the top of the cable should make a significant difference on how it behaves when it starts to orbit freely. Also, after it is free to orbit, any internal friction that is created is being borrowed from the orbital potential energy, causing it to lose some of its orbital energy and altitude. Its endpoints will probably be busy whipping around and breaking off with enough energy to leave orbit and return to the ground. Your comment at 7:25 said "to minimize strain on the cable" seems wrong, because the strain on the cable is already enormous, and the extra strain caused by a moving vehicle along the cable is relatively zilch compared to the strain that's already there. Besides, there's probably no physical contact between the cable and the vehicle, since it's probably using electro-magnetism to keep them apart. Eg, MAGLEV. In any case, good clip. But I want more math.
Two things I noticed is that the counterweight station in foundation provides thrust while rotating, as if the plan was to weaken the cable and then twist snap it off.
Also, the videogames halo 2 & 3, and Halo odst features a space elevator cable snap near the base and some of the aftermath. It's been 20 years so I don't recall what the exact scale of damage was in the game lore.
And I think Halo also snapped another space elevator cable in a tie in movie. 😕
You would probably need some emergency disconnect on the planet side along with some backup propulsion systems built into the cable to yeet it into space if there ever is a failure
If you would snap the caple at the bottom, with most of its weight in low to zero gravity _ would it start rising until its all out in space ?
Hang on a second Dr. my brain is malfunctioning... CTRL-ALT-DEL, okay All set. WTA? What a time to be alive!
Please do another onw about the physics of Ringworld.
Even if huge portions of the space elevator cable were to burn up upon re-entry, I wouldn't categorise the resulting damage as minimal. Even if the cable impact isn't likely to cause canyons in the earths surface, surely the cable impact (or what little remains of it) would be capable of destroying many a skyscraper in its path (killing who knows how many, in the process), or worse should it hit power stations (as we are most likely to use nuclear power stations currently for an elevator) etc.
Even if the end might burn up on re-entry, there's still 30 or so miles of cable that was previously under huge tensile strength and now isn't. It'd be like a garrotte. Fortunately, we'd know what the elevator's trajectory would be (due east in Earth's case) and only zone parks or such in the immediate crash zone. It'd only have to be ~a city block wide given the relative size of the cable.
In the books Trantor had a population of 40Bn. The only reason the loss of life cause by the "Terror attack on the star bridge" would not be a statistical rounding error when compared with the typical birth and death rate is because of the politics involved.
Given that the cable would fall along the equator, your concerns would be real, but minimal, outside anything but possibly Brazil
great video. What are your thoughts on space elevator alternatives. Heinlein's The Moon is a Harsh Mistress describes what is essentially a large rail gun on top of a mountain to launch crafts into orbit. It seems like this idea would have many of the benefits of a space elevator but without the engineering complexity or risk of a large-scale catastrophe in the event of a failure.
I think it is even more of an engineering challenge than a space elevator.
They've explored using hydrogen propellant instead of a railgun in the US Navy called Project Sharp
Google SpinLaunch. =)
Disney world has just opened a new "orbiting restaurant" that requires customers to board a space elevator to get up to it.... The simulation looks pretty cool as you get to see the earth recede away below as the station gets larger above. They even have the sound get quieter as the atmosphere gets thinner and thinner. You can see people's videos on UA-cam it does look pretty neat.Its called " Space 220"... I'd be curious to know what you think of their ideas.
It looks really cool! The more space related things we get the better to help inspire people to look up!
Very fascinating.
How long would the space elevator take to ascend if it takes 14 hours to descend?
I am just imagining "The Girl From Ipanema" instrumental looped for 210 times while the space elevator takes 14 hours to descend.
There are also untethered rotating elevator Skyhawks. Conservation of momentum.
If you actually made a space elevator, you would want two space stations. One being the counter weight as described here, and one being a station at geostationary orbit would allow you to launch spaceships to go to other locations - other orbits or other planets. Anywhere else and after you detach you would be at the wrong speed thus creating a very rapid acceleration. Although, I guess if you could build a space elevator, you could figure out how to detach at any point along it...
Another interesting point not discussed, but I assume to be the case, if you are not at geostationary orbit I assume you would feel a force that would create a sensation of gravity.
Loved the video! Do you think going with an Orbital Ring as opposed to a Space Elevator would be easier? The ring can be made only a couple hundred KMs up, so the tethers only have to support that much weight as opposed to trying to stretch it up to geosync. The only downside is that once you reach the ring, you have no orbital velocity, so you have to expend energy to get up to speed. But at least there's no atmosphere anymore.
Just out of curiosity, what happens to the Cable at the base if a hurricane or other significant weather system hits it? To be sturdy enough to withstand a hurricane seems to argue against the necessary lightness of the Cable.
Oh, here's another problem... We don't know the size of Trantor compared to Earth, but given the sheer MASS of the space elevator in Foundation, I would believe not only that the center of mass of Trantor would be well OFF axis, but would even threaten to PULL the planet into an exotic orbit of its sun. Perhaps the rotation of Trantor would be somewhat erratic as the elevator daily pulled harder as it swung away from and then swung in the direction of planetary travel.
You've explained an incredible amount about the physics on a completed space elevator, however what I'm struggling to imagine is how one would be built to begin with. If you start from the ground and work your way up, if the cable isn't heavy enough it won't have the rigidity to build directly upwards. So instead do you have a spacestation at geostationary orbit first and build down, then extend the orbit slowly once it's connected? Again, then it would be traveling too slow at the point of connection and would collapse. So where do you start? If the latter is the solution, getting all the materials up there to build down seems like a waste as it would impose the original problem of leaving the atmosphere with rockets to build the initial cable.
You begin the build from geostationary, paying out cable both Earthward and anti-Earthward. If you were a smart astroengineering company, you first went out to the first likely size Carbonaceous Chondrite asteroid to source your carbon for nanotubes, instead of paying a gajillion Terran Cryptodubloons to source Carbon from the deep gravity well of Earth.
Would the tether really burn up in the atmosphere though, its relative velocity to the atmosphere would not generate enough braking force for that to happen as I see it?
The "end game" of a spacefaring civilization is not a space elevator i'd say. It's more like an orbital ring. maybe you could do a video on those along with some ideas on how they'd work, their practical applications and how you might construct one. Just a suggestion but I'd be interested in your take.
Probably a hybrid. An orbital ring with multiple tethers around the globe. The "problem" is that the ring is then also needing to support those tethers
@@DontScareTheFish Sure but I mean all orbital rings have/need tethers, otherwise, what's the point of them? As for supporting the tethers, easy, you just "overspin" the ring to a velocity greater than its orbital height usually dictates.