NASEM Space Studies Board 17 novembre 2021 Musk évoque les avancées de Starship de SpaceX, les plans de lancement orbital et l'exploration de Mars lors d'une séance de questions-réponses avec le Space Studies Board des National Academies.
Musk évoque les avancées de Starship de SpaceX, les plans de lancement orbital et l'exploration de Mars lors d'une séance de questions-réponses avec le Space Studies Board des National Academies.
Transcription Session Chair
Okay, well, welcome to our last open session of this meeting. Subject is SpaceX Starship. And we are very pleased to welcome Elon Musk, who leads SpaceX, Tesla Neuralink and the Boring company. As the founder and Chief Engineer at SpaceX, Elon Musk oversees the development of rockets and spacecraft for missions to Earth orbit. In 2008, SpaceX Falcon 1 was the first privately developed liquid fuel rocket to reach orbit. And in 2017, SpaceX reflew both the Falcon 9 rocket and Dragon spacecraft for the first time. They are also currently developing the Starlink mega constellation of communication satellites and the Starship heavy lift launch system. And we welcome you. And you can unmute yourself and I'll mute me.
Elon Musk
Great, thanks for having me. I think there may be an introductory video potentially that we can play. Okay. It does have sound, but maybe you'll.
Moderator
Andrea, can you check the sound? Car, Car.
Elon Musk
Rocket. But it's rocket on a big car.
Session Chair
Let me try that again.
Elon Musk
Okay. The sound isn't essential.
Elon Musk
It. Great. So that was just an introductory video regarding the Starship program. That was all real, no CGI there. So what we're aiming to develop with Starship is a generalized means of transporting large amounts of mass or people, but just in general large amounts of mass anywhere in the solar system. The idea behind, behind this is to have a, the first fully and rapidly reusable rocket, which is, that's the really the holy grail of rocketry. If you can have a fully and rapidly reusable rocket over a rocket, then the cost of transport of a ton to orbit drops by about two orders of magnitude, maybe better. So just as a word for really any mode of transport, if you say had aircraft or cars that were not reusable, you would see very little use of aircraft and cars because you'd have to buy a new aircraft every time you went somewhere. And if you traveled somewhere in a car that was single use, you'd have to obviously tow a small car behind you just for the return journey. So, you know, so I think this is quite profound. If we are successful, and at least from a design standpoint, it appears to be, you know, all of the calculations closed, or having a fully reusable 100 ton to low Earth orbit capability. The vehicle is very big. So one of the things that helps with reusability is scale because, for example, the electronics that control the brain of the vehicle, if you will, does not actually get any heavier if it is a big vehicle or a small vehicle. So things like avionics, control Inertial measurements, sensors and whatnot become round out to basically almost no percentage of the mass for a big vehicle, whereas for a small vehicle obviously that would be much more of an issue. So scale certainly helps. And then we're using the most advanced engine cycle, which from a physics standpoint is the that the best you can extract the most amount of momentum for a given amount of fuel or propellant, which is a full flow stage, a full flow gas, gas staged combustion engine. That's the Raptor engine. There are currently 29 of those on the base of the booster. We'll be expanding that to 33 and at 33 engines and with the Raptor 2 we'll be doing about 76, 7700 metric ton force of thrust on liftoff. So it's about 2.2, 2.3 times the thrust of a Saturn V. So it's really a very big vehicle. It's the biggest rocket ever, ever designed. And we're close to our initial launch, our initial orbital launch. We've done several suborbital flights and have been able to land the vehicle successfully. The first orbital flight we're hoping to do in January. So we've completed the first orbital booster and first orbital ship and we'll be complete with the launch pad and launch tower later this month. And then we'll do a bunch of tests in December and hopefully launch in January. There's a lot of risk associated with this first launch, so I would not say that it is likely to be success successful, but I think we'll make a lot of progress. And then we've also built a factory for making a lot of these vehicles. So this is not a case of just one or two, we're aiming to make a great many. Ultimately I think in order for life to become multi planetary, we'll need maybe a thousand ships or something like that. The overarching goal of SpaceX has been to advance space technology such that humanity can become a multi planet species and ultimately a space faring civilization. And to make true the things that we read about in science fiction and have them not always be fiction. I think this is actually quite important. Well, long term it's, it's essential for preserving the light of consciousness. Eventually something will happen to us, hopefully not soon, but either natural or man made that would cause the end of civilization. So the probable lifespan of civilization is much greater if we are a multi planet species and ultimately even go beyond our solar system. But the first step is as being multi planet Mars being the only realistic option for that so I think from a standpoint of. Yeah, like I said, from a standpoint of preserving the light of consciousness and I think we should regard as fragile. I think it's extremely important that we try to become a multi planet species as quickly as possible. Obviously along the way we will learn a great deal about the nature of the universe and it will be possible to have many more space based experiments if you have a very large vehicle capable of transporting things to orbit or the moon or anywhere at 100 times less than it currently costs. So it offers sort of profound possibilities. And I think this, you know, there's a fundamental juncture in the history of really any civilization on a single planet which is do you get to the second planet or do you not? I propose we do and I think we should do it as soon as possible. The window of this opportunity is opened now for the first time in the four and a half billion year history of Earth. It may, it may be open for a long time or it may be open for a short time. And I think we should, you know, be hasty so that just in case. It's only open for a short time. Yeah, so like I said, I think this is very important for the long term preservation of the light of consciousness. And of course we'll naturally, we'll learn a lot of science and develop a lot of technology along the way. So that, that's what Starship's all about. And we have an interesting project that we're working with Solar Polymeter at Berkeley on which is to have a really big telescope. This is taking a ground based lens that a lens that was intended for a ground based telescope and creating a space based telescope with it. So that could be I think pretty interesting and we'd love to do other things as well. So. Yeah, and I think people may know that NASA has selected Starship for the transport of astronauts to the lunar surface. So we look forward to doing that for NASA. And then I think it really could be it has the ability because of the mass transport capabilities of transporting enough mass and people to the moon to actually have a permanently occupied, I think base on the moon much as we have a permanently occupied base at Antarctica. We could have a moon research station which I think would be amazingly so. Yeah, I think anyway, this is a very profound vehicle and nothing really like it has, it's being developed or, and I don't think anything quite like it has been even proposed, but has the potential to affect human destiny in a very profound way. I'm happy to answer any questions I'm unsure quite what you'd like to know. So maybe real time questions are the best way to address what people may be thinking.
Moderator
Terrific. Thank you so much, Elon. From our board members, please raise your hands for questions. And our first question will come from Louis Demaro.
Elon Musk
I think you may be on mute.
Moderator
Yeah, still muted.
Board Member
Just saying thank you for that.
Elon Musk
It's rather big vision.
Board Member
I wonder, you know, in order to achieve this goal that you painted, what type of international collaboration do you see to get this done and what are the possibilities of actually pulling that off?
Elon Musk
Well, we're not assuming any international collaboration. We're building this thing right now and we're really building it from internal funds. There's NASA is providing some support because they tend to use starship for transporting astronauts to the surface of the moon. But this has really been an internally funded effort, probably at least 90% internally funded thus far. And we expect to reach orbit probably. I don't know if we'll get there on the first attempt, but I'm confident we'll get there next year and we intend to have a high flight rate next year.
Elon Musk
it's difficult for us to actually have national involvement because of Itar. So I'm not sure and I don't really see anyone outside the US who is building some part of what we need. So yeah, we're just doing it.
Moderator
That's great. Wonderful answer. Next question will come from Adam Burrows.
Board Member
Fascinating vision.
Elon Musk
I don't know where to begin, but I will ask just a technical question. It was surprising to many that I believe you chose a stainless steel for the vehicle. I could be wrong, but what were the technical and engineering reasons for that? And don't stint on the details. Sure. That's I think a very interesting question because to a lot of people intuitively they would think of steel as being heavy and rockets need to be light.
Elon Musk
Well, that seemed pretty. A pretty odd choice picking a heavy sounding thing for rockets, especially orbital rockets that need to be very light. I mean the nature of Earth's gravity being quite strong and the dense atmosphere means that you really have to have an incredibly good propellant mass percentage and you have to have very efficient engines to get anything to orbit at all. So then why steel? So we started off with an advanced composite. So intuitively if you ask people understand materials, they will say we want to make something incredibly light. They'll say probably you would want to use state of the art carbon fiber composite. That's usually what they'll say. And that's what we started out with, which was really a very advanced carbon fiber. And actually it was only made in very small quantities. It cost $130 per kilogram. So it was very expensive material. And there are some challenges if you want to make the primary structure out of carbon fiber, which is that you've got to contain cryogenic fluid and you need gas in sort of what's called Elliot gas pressurization gas to pressurize the propellants in the main tanks and feed the engine turbo pumps with the given inlet pressure. So if you have a carbon fiber tank, because it tends to be porous and also potentially flammable when subject to warm gaseous pure oxygen, because our vehicles are postulously pressurized. So the oxygen tank is pressurized with gaseous oxygen and the fuel tank is pressurized with gaseous methane. So the resin and the carbon in the carbon fiber is potentially flammable with hot pure oxygen gas. So you'd have to have some kind of liner. So when you look at the full mass and complexity of a carbon fiber system, you start having things that reduce the mass efficiency of carbon fiber, such as having an inert liner and being worried about gas permeating through the carbon fiber and that kind of thing. So then. But it still would be an okay choice. However, we were having a lot of trouble making progress with the carbon fiber because this is a 9 meter diameter rocket. And so you're wrapping carbon fiber with typically in this case, 60 or 220 plies depending upon where you are in the tank. And you have to get all of those wrappings accurate and not leave bubbles or separator sheets or all the things that typically happen. Or you've got to scrap the whole thing and then you've got to get good mass properties, put it in autoclave and put it under a large pressure. And then you need a gigantic autoclave because it's a 9 meter diameter with a 70 meter long boost stage. So this is autoclave from hell. And we just weren't making rapid progress with this material. So then I. So then the next step, the next thing. The other two materials worth considering are a high strength form of aluminum or aluminium or potentially steel. So for Falcon 9 we use aluminum lithium, which is the highest strength weight aluminum alloy that you can use. Very difficult to weld, but that's what we use for the primary structure of Falcon 9 then. But the problem is it's very difficult to weld. You need to do friction stone welding. And also the material cost is quite high. So you Know that sort of material cost arguably on the sort of $40 a kilogram level and like vertical to world. And then there's the steel. Now the interesting thing about 300 series stainless steel is that its properties at cryogenic temperatures, its strength properties increase dramatically. So if you were to look at the material properties of room temperature, you, you'd be like, oh, it's not that great. But now go. Now go look at the temperature properties at liquid oxygen temperature. Oh, actually much stronger also. No, no meaningful increase in brittleness. So you still has high toughness. At cryogenic temperatures it is much stronger. Depending on how cold you go up to twice as strong. And then the. Yeah, so and then you can also cold work it. So again, if you go sort of full hard cold work and do the final bit of cold work at cryogenic temperatures, you get outstanding strength properties which are roughly equal to an advanced carbon fiber. In our case, for starchip, both the fuel and the oxygen are cryogenic. So this helps a lot. Whereas for Falcon 9 use cryogenic oxygen, but kind of room temperature kerosene fuel. So anyway, so we're both. This is quite a long explanation, hopefully interesting. If both fuel and oxygen are. Fuel and oxidizer are cryogenic. Now you get the strength properties in the primary structure of both tanks. And so both are very strong, very tough and resilient. Also very easy to weld stainless steel. And we started off with stainless steel 301 that did have some fracture toughness issues at quadrant temperatures. We switched to 304 and now we have our. We developed our own alloy which is three ox, which is better than either 301 or 304. So and so. So now stainless steel only costs about $4 a kilogram. So we're from $130 a kilogram advanced carbon fiber to $4 a kilogram stainless steel from 120 plies to one ply. It's just coil from the mill and basically the same strength and very high toughness and resilience and don't even need to paint it, which is great. Paint is, you know, not paint on a big vehicle, weighs many tons and it's quite difficult to paint big things. So but now there's another advantage. So obviously you can tell I'm a huge fan of stainless steel. Stainless steel and I should get a room or something. So the. So in making the vehicle reusable. So now the. It's coming in very hot. So the ship is coming in at hypersonic velocities coming, you know, kind of like a Mach 25 entry velocity. So this is, this would just obviously just melt it. And, and if you've got steel, your melting point is much, much higher than aluminum. And you can have it handle much better temperatures than carbon fiber because the resin tends to have problems. Like you can basically go, you know, anything much above say 200 Celsius, or for carbon fiber or aluminum, you start falling off a cliff from a strength standpoint. But for steel, you go 800 and it's fine. Even a thousand can be fine. So for the ship, this means that the heat shield mass is significantly reduced because the heat shield mass is determined by the temperature on the back of the tile that it then transmits to the hull. So if the hull is steel, you can have thin heat shield tiles, whereas if the hull is carbon fiber or aluminum, you have to have thick heat shield tiles. And you also need no heat shielding at all on the leeward side of the ship. So it is actually lighter than the most advanced carbon fiber vehicle. Yeah, I'm very surprised at that, but that was very, very interesting. I appreciate your long disposition on this. And I thought that the steel substituting for aluminum on re entry made some sort of sense. I didn't realize any of the other stuff.
Elon Musk
the right thing. And then it's just, and it's, it's like the cost is ridiculously low. It's like $4 a kilogram even for the special alloy that we're developing, although it requires like a mill run, it's not using anything super exotic. We might throw a little exotic, spicy something in there. But it's a small, it's, you know, it's gonna be like 0.2%. So it's still going to be like maybe $4 a kilogram, maybe 450. And then it's just very easy to weld. And yeah, I love it. It's great. And then if we want to just add something to, if you want to, you know, it's easy to repair. It's. If you want to, you know, add a sort of something to carry some wiring or plumbing or whatever, you just weld it right on. It's super easy. It's great.
Elon Musk
I very much appreciate that.
Moderator
It's a high tech, low tech. Wonderful. Our next question will come from Howard Singer Elon. Hello.
Session Chair
I started my science career watching Captain Video and reading Isaac Asimov. And you've made all that fiction real. So thank you very much. My question is what are you doing for radiation protection for the crews? And if you have you Explored the need for forecasts of the space weather conditions or the space weather environment. Sure. Well,
Elon Musk
I think there is, you know, there's always this, always some risk going into deep space. And we definitely wouldn't want to be traveling when there's like intense solar storms or anything like that, you know, for going to the moon. Like, obviously, you know, the United States has done that before and it would be great to go back and great to have a permanent base where, you know, if the costs are good enough, where we could have like a significant science contingent actually, you know, on the base permanently occupied. It'll be epic. So once you're on the moon, of course you're protected by the moon below you, and then you can put a lot of lunar regolith on top of whatever the research station roof would be. So once you're there, easy to protect. On the way, we'll have to check the weather report. And for Mars, it's going to be trickier. You know, obviously we don't have all the answers here, but. And there may be some clever ways to reduce radiation effects, but I don't think they're insurmountable.
Moderator
All righty, thanks. Our next question comes from Margie Kivelson. Hi.
Session Chair
So I'm an enthusiast for the outer planets and SpaceX is giving the Europa Clipper lift out to Jupiter. I wondered if you have comments on other missions that you would like to enhance by providing big lists.
Elon Musk
Sure. Actually, we're really excited and honored to be flying the, the Clipper mission. And you know, I mean, I think this, there could be some incredibly exciting things to discover and hopefully are under Europa. It seems like probably the best place for some strange life. So hopefully we find some really cool things. So yeah, I can't wait to launch the Clipper and that'll be on a Falcon Heavy currently with the starship. We could like, the great thing about Starship is it really should enable us to send very big things and also to send them fast and like need much less in the way of sort of planetary gravity assists and that kind of thing. So especially if we could build a propellant generation on the moon, then we could really send something with very high Delta B and if we have a base on Mars with high Delta B now you could really, you can basically planet hop from Mars to maybe Ceres to maybe one of the moons of Jupiter and ultimately all the way to the outer solar system. Basically any place we can put the, the gas station that, that gives us another whole leap forward. So ultimately Starship is Designed to be a generalized transport mechanism for the greater solar system. And so it's really whatever you can imagine being, you know, if you could, if you could get, you know, 100 ton object to the, the surface of Europe, there's a lot more you can do than with a smaller object. So yeah, I think it's very exciting. Obviously we still have a lot to prove, but architecturally it is capable of transporting kind of almost any arbitrary mass to any solid surface in the solar system.
Moderator
Wow, terrific, thanks. And Margie is actually leading the team building the magnetometer that you will be taking to Europa on the Clipper. Our next question comes from Steve macwell.
Elon Musk
Hi Elon, thanks so much for your presentation.
Elon Musk
what are your kind
Moderator
of plans for humans to Mars in
Elon Musk
terms of timescales and are you going
Board Member
to send folks there for kind of
Elon Musk
a shorter stay or you think a longer stay and bring them back at least initially?
Board Member
I'm not sure.
Elon Musk
I think so. The first thing we'd want to do is confirm that we can land the ship safely on Mars. And so that might be. It would want to probably land two or three, I think before sending people and just confirm that we can land safely. So, you know, and actually on those missions we could obviously put, put a lot of scientific instrumentation that I would recommend putting the lower cost scientific stuff on the first mission. But we'll certainly have propulsive landing very reliable on Earth as we've been able to achieve with the Falcon 9 booster. It's now knock on wood. So it's quite normal for the rocket to land safely and we'll do the same with Starship. And then I'm not sure quite what would happen. I mean, we might be working with NASA or maybe NASA and other countries to send people to Mars. But I view this very much as what set of actions can we take that maximize the probability that the future is good for civilization? You know, like what are sort of like civilizational risks that we can potentially mitigate. And I just think being a multi planet species is a tremendous risk mitigation for human civilization. And as we know, eventually Earth will become, if you wait long enough, Earth will become uninhabitable. So in the long run we are obviously all dead. But, but I think the, you know, the technology that we develop in traveling from Earth to Mars I think will be just a very powerful forcing function for the improvement of space transport. You know, the initial boats that crossed the Atlantic and crossed the Pacific back in the sailing days were really terrible, you know, so yeah, they Were often just plain sink. And as once there was a reason to do large amounts of ocean trade, the sailing ships, the wooden sailing ships got dramatically better. And, and so but you kind of have to have that forcing function. So that, that's what I think will happen. And we'll get much better at space transport. And I think this will also be very important if, you know, if there's like a potential Earth collision event from some comet or something like that. You know, the asteroids we can predict fairly well, obviously, but there's this massive cloud of comets out there that, you know, we don't know the situation. So. And they come in pretty fast. So there's always some risk of a comet like taking out a continent or you know, there's a specific, like they talk a lot about extinction events where, you know, almost all life was destroyed on Earth, but they don't talk that much about the ones where, well, it was just a continent. There's plenty of sort of continent level extinction events that have occurred in the fossil record. And they're like really so common as to really not really generate much attention. But if we've got large rockets that could potentially do something about that, that then that could be, you know, that could one day save billions of people. But we've got to have big rockets and much more advanced space technology in order to protect against a comet coming in from far away.
Moderator
Okay, thank you so much. Perfect. Thanks Ilan. Our next question will come from Harlan Spencer.
Board Member
Elon. Thank you for sharing your time and your vision with us. I had a question about looking back the history of exploration, human exploration, as we ventured from one place to another. Scientific discovery has always been an element of that. And you've shared a little bit about some opportunities there, but I was hoping you could share a little bit more. When you think about the aspects of scientific discovery that will accompany becoming a multi planet species, what are the kinds of things that you're thinking about in terms of what we would discover along the way?
Elon Musk
Well, I think being able to really have heavy duty science research on the moon and on Mars, where you could really just go anywhere you want, drill core samples anywhere you want, I think we'd learn a tremendous amount. As compared to having to send fairly small vehicles with limited scientific instrumentation, which is what we currently do for Mars and the moon. So just having people there who can dynamically decide what they're going to do, and really being able to analyze the whole history of the planet, I think we learn a tremendous amount and. Yeah, and that would obviously extend over time through at least the greater solar system. So you know, I mean, yeah, I mean I studied physics because I was just trying to find what's the universe all about, how does it work? Where did it come from? Why are we here? And I actually kind of got sort of depressed at one point because I was like man, this doesn't seem to be any meaning to life. It just seems to be like, you know. And then I made the mistake of like reading the German philosophers as a teenager that made it was quite depressing. But then I, then I read Douglas Adams the Chaga's Guide to the Galaxy, which is really a book in philosophy, disguises humor and he makes point that in know the question is harder than the answer. And really basically the answer is the universe. And we kind of need to figure out like what questions to ask about the answer to that is the universe. And that's the question is the hard part. And then the answer is easier by comparison. So I'm like, I don't know, like why are we here? How do we get here? Is this real? Is this simulation or something? At least if we go to these other planets we'll make the simulators work harder and have to buy more computers to run the simulation or something, you know. But yeah, I mean I think it's, and if we are able to at least be like a multi planet species within the solar our solar system, then hopefully we can develop the technology to send probes to other star systems and eventually maybe send people, although that's tough, but we could certainly send robots to, to robot probes to all the nearby star systems and yeah, trying to figure out what's the meaning of life and what's going on and are there any aliens out there? Where are.
Moderator
Do you have time for a question or two more?
Elon Musk
Yeah, as much time as you like.
Moderator
Oh, wonderful. All right, I do have one question from a board chair and it's this One aspect of SpaceX that has distinguished it from the previous organizations has been its willingness to embrace failure as a development tool. When do you think you will be able to start selling starship launches at prices significantly less expensive than Falcon 9? Say five to ten times less? Sure.
Elon Musk
Actually I think it's not that, it's not that far away. I think probably two years from now. So our rate of progress on starship is very rapid and like I said, we're actually getting ready to do our first local orbital launch attempt within the next few months. We're expecting our license approval from the FAA around the end of this year and then so that probably means a launch attempt in January or perhaps February. And then we're actually building the, the factory to make lots of starships and make lots of engines in parallel. So there will be many, many vehicles. The engine build rate is currently the biggest constraint on how many vehicles we can make because There are currently 29 engines on the booster and there will be 33 even at a higher thrust level. So that means 33 engines per booster. And these are big engines. These are, you know, the Raptor 2 is a roughly 240 ton thrust engine. So we're talking like five or six hundred thousand pound thrust engines. So really quite, quite intense. In fact, I'd say that building the production system for starship is much harder than the design of the starship itself. But we have that in progress and we intend to do hopefully a dozen launches next year, maybe, maybe more. And if we're successful with it being fully reusable, it means that we build up the fleet just as we are with Falcon 9 and the Falcon 9 booster, which is reused. We lose the upper stage every time, but we almost always recover the booster. So basically we intend to complete the test flight program next year, which means that it's probably ready for valuable payloads that are not kind of in the test, not for testing basically, but actual real payloads in 2023. So quite soon.
Moderator
Great, thank you so much. Next question from Ned Wright. Ned, I think you're still muted. Won't we all be glad when we don't say that all the time?
Session Chair
you have to preserve cryogenic propellant for six to eight months to actually be able to land on Mars. I wonder what your plan is for that.
Elon Musk
Yeah, so the landing propellant for Mars would be in separate header tanks. So these would be spherical header tanks for Mars. There would probably be, it might be contained inside the main tanks or there would be up in the cargo section, but well insulated. So we'd obviously have to have extremely well insulated header tanks for landing that are not the main tanks. So that's what we'd have for Mars.
Moderator
Great, thanks. Reza Wexler is the next question. Yeah, so changing topic to something that's happening before we have the possibility to be a multi planet species. I also study the universe and I'm trying to understand how it works and how it got here. And as you know, the satellite constellations from Starlink and other sources are already having a huge impact on astronomical observations. And this is really going to significantly limit the science potential of the next generation of observatories if we don't have a core shift. So what role do you expect Star SpaceX to play in working with astronomers and regulatory agencies to mitigate this?
Elon Musk
Well, SpaceX already works with regulatory agencies and with the astronomers. And generally what we see is the telescope that is perhaps most sensitive to this is Vera Rubin. And we work directly with the Vera Rubin team to make sure that their observations will not be affected by Starlink satellites. And my understanding is at this point they are comfortable that it will not be an interference. For Vera Rubin, there's a slight risk of capacitive coupling between some of the basically sensors there. But this, which can create ambiguity. But we're confident that we can work around that.
Moderator
Great, thanks. Our next question comes from John Karras.
Board Member
Elon, thanks for all your time today. Appreciate it. Kind of going back to prior question about long term storage of cryogenics for whatever mission, but I realize or I believe that your architecture for starship to go beyond low Earth orbit to go to the moon has, you know, cryofluid transfers and things like that and you know, long term cryofluoroids, you know, cryo fluid storage, low boil off.
Elon Musk
Not easy problems. Yeah, yeah, no,
Board Member
so not easy problems. So the question I have for you is, is, you know, what are your plans to, to mature that technology before you have to rely on it to go to the moon like in a year or two?
Elon Musk
yeah, so I mean there's a lot of ways to address it by having a launching one vehicle that is very well insulated but does not return to Earth, effectively a propellant depot. So if you take a ship, a starship, and you take the heat shielding off and replace that with thermal insulation, like you know, a multi layer installation that's just very, very good at keeping things cold, then you can have one ship up there that is effectively just turns into a propellant depot and then you send tankers up there to dock and transfer propellant. And so it should be able to be there for a while. And then whatever ship you want to go to the moon, you go up and dock with the depot, transfer propellant and off you go. So that's a rough plan. We're pretty good at docking at this point. We've docked with the space station a couple dozen times and the space station is a very difficult thing to dock with because we don't control both sides of it. And so that is very challenging docking. Whereas docking with our own vehicle is just comparatively easier.
Board Member
Yeah, but both of These technologies have really only been demonstrated on very, very small scale. So your, your scale is a lot larger and I think poses other problems. So good luck in solving those.
Elon Musk
Yeah, no, I don't think we'll just sort of like, you know, it's not exactly a walk in the park. So I think this is hard, but it is necessary and it's the only way, at least with that, with current physics, to, to actually make things work. And obviously, you know, like aerial refueling is used quite a lot with, with aircraft. And so this is, you know, taking that concept, just doing it in orbit. And so like we don't, we know that success is one of the possible outcomes. We're not breaking any physics, you know, physics is the law and everything else is a recommendation. So just because it's at least in the set of successes. At least in the set of possible outcomes.
Moderator
Yeah, great, thanks very much. Next question will come from Amanda Hendricks. Hi there. So I'm a co chair of the Committee on Planetary Protection and our committee is concerned with preserving the validity of future astrobiological experiments on Mars and other places in the solar system. Searches for life extinct or extant. And I wonder if you can comment on SpaceX's planetary protection plans for Mars. Sure.
Elon Musk
Well, I mean, first of all, it's not like we're relaunching to Mars really soon. I mean Mars is a ways off and the, you know, but there is, you know, fundamentally a choice to be made which is are we going to try to be a multiple planet species? Which would mean like at least in one spot on Mars that there is human biology like that we will be, you know, pretty hard to avoid no biology if you send humans there. They're biological creatures. But I don't think this is going to invalidate research on the rest of the planet. Mars is a big planet and so, and there have been rocks that have been knocked off of Earth and landed on Mars and that kind of thing. So. But yeah, I think we'll, you know, you wouldn't want to sort of spread biological debris all over Mars, but I think we will have to put at least somewhere, if there are people going there, at least in one spot and then just make sure we try to contain that, not have it sort of spread around. Yeah, and I guess same for the moon and other places.
Moderator
Thank you, Elon. We'll just take a question or two more. Next question from Larry Paxton.
Board Member
Hi, thanks for your time. I have a question that was engendered by a remark you made in passing that I think is Very interesting. Which is where you said that there's a window of opportunity for us to get off the planet. And the question that occurred to me was you followed it up with saying that you didn't know how long that window of opportunity would be open. And you mentioned in passing, of course, the traditional things like, you know, exogenous forces like cometary impact or near Earth object. But I was wondering, you know, with all these compelling reasons for us to get off the planet and including the compelling reason to have another refuge for the human race, what do you see as the biggest threats? And in particular, we have a wide range of expertise here. We've been talking about some of the problems that we think are the most important that are unresolved yet. I just wonder what you felt were the most important issues for us as a human race.
Elon Musk
Yeah, I mean, in general I've thought about this quite a lot, which is not to say that I've thought about it correctly, but I thought about it a lot. One of the bigger risks on Earth would be that we need to transition to sustainable energy. Even if one discounts the CO2 capacity of the oceans and atmosphere, eventually we will run out of hydrocarbons to burn. And so we need something that's long term sustainable. So that's sort of, you know, I kind of put my time between Tesla and SpaceX. And so Tesla's trying to accelerate the advent of sustainable energy and that's, you know, to mitigate the risk on Earth. And then SpaceX is intended to mitigate like longer term risks that could potentially extinguish consciousness as we know it. I mean, we got the sort of delicate candle of consciousness sort of flickering in the darkness here. And I don't know if you guys have seen any evidence of aliens, but I sure haven't. I get asked that a lot. So, I mean, I think the Fermi paradox is just an incredibly interesting question and I'm not sure who said it, but the like it appear to be if there may, there's either a lot of aliens or none and equally those answers are equally terrifying. So anyway, so I think. But with respect to nearer term risks on Earth, obviously sustainable energy and potential Nonlinearities in the CO2 ppm in the atmosphere are a concern. If we start doing things like melting the Siberian tundra and that kind of thing. I'm probably less alarmist than most on climate change. I put myself in the moderate category on climate change. I just think it's the amount of inertia associated with the hydrocarbon economy is so Gigantic that it will require a long time to make that transition. And so it's probably better to start it sooner rather than later. And that's why I describe fundamental good of Tesla as the degree to which it accelerates the advent of sustainable energy. It will happen, I think anyway, but faster is better. Then as for risks on Earth, I mean, there's always good old nuclear Armageddon, you know, that's still one of the things that's not out of the question. There's still a lot of nuclear missiles pointed all at us in the US and many parts of the world. I don't know what quite that risk is, but it's not zero. I think there's maybe some counterintuitive risks or that people don't put that much attention on. If you look at the growth rate trends, birth rate trends are very negative and so. And in many countries are seeing population decline with no end in sight. So I think there's, I think the very low birth rate I think is actually quite a significant risk, but an underappreciated one. So. Yeah. And for population prediction, I would recommend taking things like the number of babies born last year and just multiplying that by the probable lifespan. And if you do that, you'll, I think you'll see numbers that are very, very bad for future population and with an inverted demographic permit. So you've got a lot more older people and then fewer middle aged people and then eventually just very few youngsters. And this will necessarily lead to resources being applied to taking care of the elderly instead of advancing science or advancing civilization. I'm quite worried about that one because I see no reversal of the trend. And you know, that would, you know, civilization will die with a bang or a whimper. That would be dying with a whimper. Then there's obviously, of course, you know, a pandemic that's like Covid, but which has a much higher mortality, sort of a long, you know, high contagion, highly contagious, long incubation period, high mortality type of pandemic. That's clearly a risk. AI is, I think, maybe more risk than people realize. Ironically, smart people tend to think AI is less of a risk because they think that they're so smart. But actually we're just humans and we're quite dumb. It's amazing we got this far, frankly. So if you see the advancement of AI, it's clear that AI will exceed human intelligence in every way if these trends continue. And the list of things that the human mind can do better than AI is less and less every year. So hopefully that AI is coupled to human will, but it might not be. The long term goal of neuralink is to achieve sort of better symbiosis with AI and with kind of human mind. In the short term, neuralink I think will help solve a lot of, of brain injuries and diseases and spinal injuries and that kind of thing. But long term, because one of the things that I'm getting quite esoteric here, but the, we're, we're already a cyborg really in the sense that our phones and computers are an extension of ourselves. And you can say we arguably have sort of, sort of the primitive kind of limbic system, the cortex, the higher thinking. And then we've got a tertiary layer which is our, which is silicon in the form of our computers and phones and everything.
Elon Musk
we have already somewhat merged with computers. But the issue we have is the communication rate. The bandwidth with the computers is low, especially output. If our output is two thumbs, that's, you know, we're talking maybe 10 bits per second or something like that, maybe 100. Best case, it's a very slow output. And as the intelligence of the computer grows, if that communication link remains very tiny, I think we will necessarily decouple from computers just because our rate of communication is very slow. And so if we can solve the I O bandwidth question and by increase it by a thousand or more, maybe a million, then the, you could have human machine symbiosis that is much better. I mean, that's at least one approach. Let's see, what else is there? I mean, religious extremism, you know, if that, that becomes, if that grows over time. Religious extremism is certainly a threat to advancement of science. So depending on how far that goes, that could be an issue. What do you think?
Board Member
I only add, I think that this is a fundamental question because as you said, the Fermi paradox, there should either be a tremendous number of alien civilizations or there is some gate that so many civilizations have failed to get past. And the question is, are we going to fail to get past that gate as well?
Elon Musk
The great filters. Yeah. So I think at least one of the great filters is does a civilization become multi planetary or not? Yes. If a civilization does not become multi planetary, then then eventually the sun's going to expand and boil the ocean and that's game over. And actually think about it from a percentage standpoint, it's been around four and a half billion years. Then it took us 1.5 billion years to get this far. It may be as soon as another 500 million years and the sun might have expanded enough by that time to boil the oceans. Potentially it's not 500 billion years, it's not much beyond that. Which is basically means that if it took 10% longer for civilization to evolve, it would never have evolved.
Moderator
There's an interesting one. Elon, do you have time for one more question? Wonderful. All right, Jill Dahlberg, please. So let me just say I feel
Elon Musk
lucky that you are here.
Moderator
So thank you. And not just here in our panel. You're very inspiring. My question is mundane. You're going to have these rockets, they're going to go up and they're going to go to two places that are going to need energy. The Earth needs a lot of energy as well. So what are your plans for making energy? I'm thinking space based solar power or something like that. Does your company have plans for plethorating energy systems you're going to need?
Elon Musk
Well, Tesla does do solar power and solar is actually there's quite an amazing amount of energy that reaches us from the sun that, I mean really when you think about it, Earth is almost entirely solar powered. If it were not for the sun, we would be a frozen dark ice ball at 3 degrees Kelvin. So apart keeping us warm and not super cold and frozen and dark is pretty helpful. And then the almost the entire ecosystem is solar powered. You know, plants are a solar powered chemical reaction and you know, apart from chemotropes at the bottom of the ocean, it's basically, you know, everything's solar powered. So really talking about just like a little bit of incremental power from the sun being used to power civilization. The, you know, as a sort of good rule of thumb is because you get about a kilowatt per square meter of solar energy in a square kilometer. There's a million square meters. So now you've got a gigawatt of solar energy per square kilometer. And so if you've got like 25% efficient panels and there are maybe 80% of the area is panel of, then you've got basically 200 megawatts per square kilometer of solar power. And so then if you say well okay, then you really won't need a very large area to power the entire United States with solar, like a little corner of Utah or Texas, obviously you prefer it to be distributed, but you can just say like, okay, how much is actually needed to power the US and it's somewhere between a square that's roughly 150 to 200 kilometers on a side will power the entire, entire United States. So it's really clearly no problem to power civilization with a, with solar. And then of course there's wind and you know, I'm actually pro nuclear vision wise and there's also hydro and geothermal. So I think we will solve Earth's energy needs and they are being sold. If you look at the growth of wind power and solar power, it's, it's really has a very high growth rate and needs to be paired with batteries in order to, because of the intermittency of wind and solar. But the combination of solar plus battery will completely solve all of us energy needs. In fact, for satellites that are in orbit, that's all they use is solar panels and a battery. And what is Earth but a large satellite? Sorry, I think you're.
Moderator
Yeah, I was thinking something more grandiose like a space based solar power system. But you have a good argument. You would just use solar on Earth and plethora. I like that. Thank you.
Elon Musk
Looks great. Because if we think civilization uses a lot of energy, but it's actually very tiny compared to the amount of solar energy that reaches the Earth every day. Yeah, it's just there. I get asked a lot about fusion and in my opinion like if you, if you just make a very large thing of magnetically confined fusion, you could absolutely make it work. I don't think any, any really major breakthroughs needed to make fusion work but, but I think it's, it's unnecessary to make fusion work because we've got a giant fusion reactor in the sky that just shows up every day with, doesn't require any maintenance. So it's a low maintenance fusion reactor, shows up every day. So if we just, just catch the energy from you know where catch it, it's just keep loving all this energy at us. Just catch it with the photovoltaics and stored in the batteries and it'll, that'll, that'll solve for everything. Basically. Yeah, we need a lot of batteries but there's also like the next question might be is there or do we face some materials limitation with batteries? And the answer is definitely not. I think most, the vast majority of stationary storage will use an iron cathode lithium ion battery. So there's obviously plenty of iron on Earth. No shortage of iron. There's also no shortage of lithium. Lithium is extremely common on Earth basically everywhere. And so if you have basically an iron phosphate cathode with a graphite anode and lithium carbonate, there's enough of that on Earth to power many civilizations. Several easily order magnitude larger civilization than ourselves. Could be powered with battery materials that are readily available. So I don't want to suggest complacency here, but just that there is a very clear path to a sustainable energy future.
Moderator
Okay. Thank you. Elon, we just want to thank you so much. The National Academy of Sciences is so pleased to have you here with us today. Paul Worcester is a member of the Space Studies Board, and this is also the board on Physics and Astronomy. And just thank you so much for the time and the interaction with our members and answering so many questions so graciously. I know it's past the 7pm hour on the east coast or wherever you are.
Elon Musk
Well, thank you for the great questions, and it was an honor to speak to everyone.
Moderator
Thank you. Thank you.