NASEM Space Studies Board

Okay. Well, welcome to our last of open session of this meeting. Uh 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 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 a 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. Right. Um thanks for having me. Um I think there there may be an introductory video potentially that we can play. Okay. Say that emphasis.

It does have sound, but maybe you'll Andrea, can you check the sound? Mhm. car Mhm. car rocket but rocket on a big car Yeah. Let me try that again. I was muted. Okay. The the sound isn't essential but Hi. All right. Uh great. So, uh that was a just an introductory video regarding the Starship program. Uh that was all real. No no CGI there.

Um so, uh what we're aiming to develop with uh Starship is a generalized uh means of transporting uh large amounts of mass uh or people, but it just in general large amounts of mass uh anywhere in the solar system. Um the idea behind uh the the behind this is to have a the first uh fully and rapidly reusable rocket, um which is but that that's the really the holy grail of rocketry.

Um if you can uh have a fully rapidly reusable rocket or orbital rocket, uh then the cost uh of transport uh you know, of of a ton to orbit drops by about two orders of magnitude, uh maybe better.

So, um you know, just as a word for uh really any mode of transport, um if you uh say had uh aircraft or cars that uh were not reusable, you would see very little use of aircraft and and cars because you'd have to buy a new aircraft every time you went somewhere. Um 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.

Um so, uh you know, so I think this is quite profound. Um if we are successful and and at least from a design standpoint, um it appears to be uh you know, all of the calculations close for having a fully fully reusable 100 ton to lower the orbit capability. Um The the vehicle is very big.

Um so one of the things that helps with the reusability is scale because for example, the um electronics that control the the brain of the vehicle, if you will, uh does not actually get uh it any heavier uh if it is a big vehicle or a small vehicle. So things like uh avionics and control and inertial measurement sensors and whatnot um become round out to basically um almost no percentage of the mass if for a big vehicle.

Um Whereas for a small vehicle, obviously that would be much more of an issue. So scale scale certainly helps. Um and then the uh we're using the most advanced uh uh engine cycle, which from a physics standpoint is the the the best. You you can extract the most amount of momentum for a given amount of fuel or propellant, uh which is a a full flow stage a a full flow uh gas gas staged combustion uh engine. Uh that's the the Raptor engine.

Uh there are currently 29 of those on the base of the booster. We'll be expanding that to 33. Um and uh at at 33 engines and with the Raptor 2, we'll be doing about um 76 7700 metric ton force of thrust on lift off. Uh so it's about uh two 2. 2 2. 3 times the thrust of a Saturn V. Um so it's it's really a very big vehicle. It's the biggest rocket ever um ever designed. And and and and we're we're close to our initial launch.

Um our our initial orbital launch. We've done several suborbital flights um and have been able to to land the vehicle successfully. Um the first orbital flight uh we're hoping to do in in January. Um so we've completed the the first orbital booster uh and first orbital ship um and will be complete with the uh launch pad and launch tower uh later this month and then we'll do a uh a bunch of tests in in December and hopefully launch in in January.

Um there's a lot of risk associated with this first launch, so I would not say that uh it is likely to be success uh successful, but I think we'll we'll make a lot of progress. Um and then we've also built a a factory for making a lot of these vehicles. So this is not a case of just just one or two. Um we're aiming to make um a great many.

Um ultimately I think if in order for life to become multi-planetary, uh we'll need uh maybe a thousand ships or something like that. Um the the the overarching goal of SpaceX has been to uh advance space technology such that uh humanity can become a multi-planet species and ultimately a space-bearing civilization and to make true the things that we read about in science fiction and have them not always be fiction.

Um I think this is actually quite important. Um uh it was in long term it's essential for preserving the light of consciousness. Um Eventually something will happen to Earth. Uh hopefully not soon. Um but uh either natural or man-made that would cause the end of civilization. Um so the the probable lifespan of civilization is much greater if we are a multi-planet species um and and uh ultimately even go beyond our solar system.

Um, but the first step is is um being a we being multi-planet, Mars being the only realistic option for that. Um, so I think from from um the standpoint of Yeah, like I said, from the standpoint of preserving the light of consciousness and um which I think we should quite as fragile, um I think it's extremely important that we try to become a multi-planet species um as quickly as possible.

Um, I'll say along the way we will learn a a great deal about the nature of the universe. Um, and there will it will be possible to have many more uh space-based uh experiments if you have a very large vehicle uh capable of transporting things to uh orbit the moon or anywhere. Um, that that at um, you know, 100 times less than it currently costs.

Um, so it's it it offers sort of profound possibilities and I think this uh you know, this this there's a fundamental juncture in in the uh history of really any civilization on a single planet, which is do you get to the second planet or do you not? And I propose we do. Um, and I think we should do it as soon as possible. Um, the window of this up up shoot is open now for the first time in the 4. 5 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. Um, yeah, so like I said, I think this is It's important for the long-term preservation of the light of consciousness. Um 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.

Um and um we have an interesting project that we're working with a Saul uh Perlmutter at Berkeley on, uh which is to have a really big uh telescope. This is taking a a ground-based uh lens that a lens lens that was intended for a ground-based telescope and um creating a space-based telescope with it. Um so that that could be I think pretty interesting and we you know we'd love to do other things as well.

So um and and I think people may know that NASA has selected uh Starship for the um transport of astronauts to the lunar surface. Uh so uh we look forward to doing that for NASA. And um and then I think you know it it it it really could be it it has the ability because of the the mass transport capabilities of of transporting enough mass and people to the moon to actually have a permanently occupied I think base on the moon.

Uh much as we have like a permanently occupied base at Antarctica, we could have a sort of a a moon research station which I think would be um amazing. So yeah I think anyway this is a a very profound vehicle um and um nothing really like it has uh is is being developed or and I don't think anything quite like it has been even proposed. Uh but it's um it has the potential to affect human destiny in a very profound way.

So I'm happy to answer any any questions. I'm unsure quite what you'd like to know, so uh maybe real-time questions are the best way to um address what people may be thinking. Terrific. Thank you so much, uh Elon. From our board members, please raise your hands for questions. And our first question will come from uh Louis Demaro. Uh thank you. Maybe I'm on mute. Yeah, still muted. Hi. There you go.

Just saying uh thank you for that and some rather big vision. Uh I I I wonder, you know, in order to achieve this goal that that you painted, what type of uh international collaboration do you see to get this done and you know, what are what are the possibilities of uh actually pulling that off? Well, we're not assuming uh any any inter- international collaboration. Uh we're building this thing right now.

Um and we're uh we're really um building it from internal funds. There's NASA's providing some support uh because uh they'll they tend to use Starship for uh transporting astronauts to the to the surface of the moon, but this has really been an internally funded uh effort. Um I don't know at least 90% internally funded thus far.

Um and we um expect to reach orbit uh you know, probably I don't know if we'll get there on the first attempt, but uh I'm confident we'll get there next year and and we intend to have a high flight rate next year. Um so uh it it it's difficult for us to actually have international uh involvement because of ITAR. So, I I'm not sure I I'm and uh I I really see anyone outside the US who is um building some part of what we need. Um so yeah.

Um it we're we're just doing it. It's great. Wonderful answer. Uh next question will come from Adam Burrows. A fascinating vision. I don't know where to begin, but I will ask a just a technical question. Uh it was surprising to many that I believe you chose a stainless steel um for the vehicle. I could be wrong, but what what what were the technical and engineering reasons for that? And don't stint on the details. Uh sure.

That that's a I think a very interesting question um cuz for a lot of people intuitively they would think of steel as being heavy. Um uh and rockets need to be light. So well that seems pretty a pretty odd choice picking what a heavy sounding thing for rockets, especially orbital rockets that need to be very light.

Um I mean the the nature of Earth's gravity being quite strong and a dense atmosphere means that you really have to have an incredibly good propellant mass percentage. Uh and you have to have very efficient engines to get anything to orbit at all. Um so so then so then then why steel? So we we started off with um uh with an advanced composite.

So intuitively if you ask people who who understand materials, they will say we want to make something incredibly light. Um they will they'll say probably you would want to use state-of-the-art carbon fiber composite. Um that's usually what they'll say. Um and that's what we started out with which was um really a a very advanced carbon fiber. Um And uh actually it was only made in very small quantities. Uh it cost um $130 per kilogram.

So it was a very expensive material. Um and um and there were some challenges if want to make the primary structure out of uh carbon fiber, which is that uh you've got to make a contain uh cryogenic uh fluid and um and you need a uh gas in in in sort of what's called ullage gas, pressurization gas, uh to pressurize the propellants in in the main tanks and and feed the engine turbo pumps with a with a given inlet pressure.

So so for if you have if you have a a carbon fiber tank, because it tends to be porous um and also um potentially uh flammable when subject to uh warm gaseous uh ox- pure oxygen, because our our vehicle is autogenously pressurized, so the oxygen tank is pressurized with gaseous oxygen and the fuel tank is pressurized with gaseous methane.

Um so um the the resin and and the carbon in in the uh carbon fiber is potentially flammable um with with with with hot pure uh oxygen gas. So you'd have to have some kind of liner.

Um So when you look at the the the full uh mass and complexity of carbon fiber system, you you start having um uh things that reduce the mass efficiency of of carbon fiber, such as having an inert liner um and being worried about uh uh gas permeating through the the carbon fiber and that kind of thing. So um then uh but but it still would be an it's still an okay choice.

Um however, um we were having a lot of trouble making progress with uh the um carbon fiber um cuz this is a 9-m diameter rocket um and so you're you're wrapping carbon fiber um with typically in this case uh 60 or 220 plies, depending upon where you are on in in the tank.

Um and you have to get all of those wrappings uh accurate and not um have any bubbles or separator sheets or all the things that typically happen um or or you've got to scrap the whole thing. And then you've got to to get my good good mass properties put it in an autoclave and put it under you know a lot of pressure. And then then you need a gigantic autoclave because it's a 9-m diameter with a 70-m long booster stage.

So this is autoclave from hell. Um and we we we were 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 uh high strength formula aluminum aluminum um or potentially steel. So for Falcon 9 we use aluminum lithium which is the highest strength to weight aluminum alloy that you can use very difficult to weld.

Uh but that's what we use for the primary structure of Falcon 9. Then but the problem is it's it's it's very difficult to weld. You need to do friction stir welding and also the the material cost is quite high. So um you know that's that's sort of material cost arguably on the sort of $40 a kilogram level. Um and uh like very difficult to weld. But then and then there's there's steel.

Now the interesting thing about uh 300 series stainless steel is that its properties at cryogenic temperatures uh strength properties increase dramatically. So if you were to look at the material properties at room temperature you'd be like it's not that great. But now go now go uh look at the temperature properties at uh liquid oxygen temperature. Oh actually much stronger. Uh also no no meaningful increase in brittleness.

So you have it still has high toughness at cryogenic temperatures. It is much stronger depending on how how cold you go up to twice as strong. Uh and then the um yeah so and then then you you can also cold work it so you get if you if you go sort of full hard cold work and and 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.

Um and and this is in our case for for um for Starship, the it it both the fuel and the oxygen are cryogenic. So, this helps helps a lot. Whereas for Falcon 9, the the it use cryogenic oxygen, but kind of room temperature kerosene fuel. Um So, anyway, so where both quite a long explanation, hopefully interesting.

Um Uh if if both fuel fuel and oxygen are fuel and oxygen are cryogenic, now you get the strength properties in in the primary structure of of both tanks. Um And so, both are very strong, very tough, and resilient. Also, very easy to weld stainless steel. Um And we started off with stainless steel 301. Um That that did have a some some um fracture toughness issues at cryogenic temperatures.

Um we we switched to 304, and now we have our we developed our own alloy, which is 30X, which is the better than either 301 or 304. Um So, um and and and anyway, so so now now now stainless steel only costs about $4 a kg. So, we're from $130 a kg uh advanced carbon fiber to $4 a kg stainless steel, uh from 120 plies to one ply, it's just coiled from the mill, um and uh basically the same strength.

Um And and and very high toughness and and resilience. I don't even need paint it, which is great. Um So, paint is, you know, not weight paint can't paint on a big vehicle weighs many tons and it's a bit quite difficult to paint big things. So, So, that and but now there's another advantage. So, um obviously you can tell I'm a huge fan of stainless steel. I Stainless steel I actually got a room or something.

Um Um so, the So, for in in making the vehicle reusable, um so, now the there is coming in very hot. Um so, the the ship is coming in at hypersonic velocities coming, you know, at sort of right kind of like a Mach 25 entry velocity. So, uh this is this would just obviously just melt it.

Um and um and and and it but if you've got steel, your melting point is much much better higher than aluminum um and you can have it handle much better temperatures than than carbon fiber cuz the the resin tends to have problems. Like you can basically go, you know, you know, anything much above, say, 200 Celsius or before carbon fiber or aluminum is is you start falling off a cliff from a strength standpoint.

Um But but for steel, you go 800 and and it's it's fine. Even 1,000 can be fine. So, for for the ship, this means that the heat shield mass is significantly reduced because the the heat shield um mass is determined by the temperature um on the back of the tile uh that that that then transmits to the hull. So, the hull If the hull is steel, um you can have thin heat shield tiles.

Whereas, if the hull hull is carbon fiber or aluminum, you have to have thick heat shield tiles. Uh and you also need no heat shielding at all on the leeward side uh of the ship. So, it is actually lighter than the most advanced carbon fiber vehicle. Yeah, I'm I'm very surprised at that, but that was very very interesting.

I appreciate your long disposition on this and I'm I 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. Yeah. And and it's the right thing and then it's it's just and and it's it's the the cost is ridiculously low. It's like $4 a kilogram. And even for the special alloy that we're developing, 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 going to be like 0. 2%. So it's it's still going to be like maybe $4 a kilogram, maybe 4. 50. And then it's just very easy to to to to weld. Um and um Uh 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. It's super easy. Thank you. I very much appreciate It's a high-tech low-tech. Um wonderful. Our next question will come from Howard Singer, Elon. Uh hello. 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.

Uh my question is uh 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. Um Well, um I I I think there is um you know, there's always this always always some risk uh going into deep space. Um and and and I I um we definitely wouldn't want to be traveling when there's like intense solar storms or anything like that.

Um You know, for for going to the moon, like obviously, you know, we're the United States has done that before. Um and it would be great to go back and it would be great to have a permanent base where, you know, um if if the if the costs are good enough where we we we can have like a a significant science contingent actually, you know, put you know, on the base permanently occupied. That would be epic.

Um so um but once you're on the moon, of course, you you're protected by the the moon below you and then you can you can put a a lot of lunar regolith on top of whatever um you know, the the research station roof uh would be. Um so, once you're there, easy to protect. On the way, we'll have to check the weather report.

And but for Mars, it's going to be trickier, you know, I um I you know, I was going to we don't have all the answers here, but um and there may be some uh clever ways to reduce the uh radiation effects. Um but I don't think they're insurmountable. All righty, thanks. Uh our next question comes from Margie Kivelson. Uh so, I'm an enthusiast for the outer planets. Um I SpaceX is giving the Europa Clipper a lift out to Right. uh Jupiter.

I wondered if you have comments on other uh missions that you would like to uh enhance by big big lifts. Sure. Actually, we're we're really uh excited and and honored to uh be flying the the Clipper mission. Um and um you know, I mean, I think this there could be some incredibly exciting things to discover, hopefully are, um, under Europa. Um, it's, uh, seems like probably the best place for some strange life.

Uh, so hopefully we find some really cool things. Um, so yeah, can't wait to launch the Clipper and, um, that that'll be on a Falcon Heavy, um, currently. Uh, with with the Starship, we could like the the great thing about Starship is it it really should enable us to send very big things and also and also to send them, uh, fast. And and like need much less in the way of, um, uh, sort of planetary gravity assists and that kind of thing.

Um, so, um, especially if we could build a propellant, uh, generation, um, on the moon, uh, then then we could really, uh, send something very to very with with very high delta V. Um, and if we have a a base on Mars with a high delta V, now now you could really you could basically planet hop from Mars to maybe Ceres, uh, to maybe one of the moons of Jupiter, and ultimately all the way to, uh, the outer, uh, solar system.

Um, basically any place we can put the the gas station, uh, that that gives us a another whole leap forward. Um, so, uh, ultimately Starship is designed to be, uh, a generalized transport mechanism for the greater solar system.

Um, and, um, and so it's it's really whatever you can imagine being, um, you know, if you if you could if you could get, you know, a 100 ton object to the surface of Europa, there's a lot more you can do than with a smaller object. Um, so, um, yeah, I think it's it's very exciting.

Um, obviously we still have a lot to prove, but architecturally it is a capable of um transporting kind of almost any arbitrary mass to to any solid surface in this solar system. Wow, terrific. Thanks. And Margie is actually part leading the team building the magnetometer that you will be taking to Europa on the Clipper. Uh our next question comes from Steve Maxwell. Hi Elon. Um thanks so much for your presentation.

Um I was wondering um what were your what are your kind of plans for humans to Mars uh in terms of timescales and uh and you know, are you going to send folks there for kind of a shorter stay or you think a longer stay and bring them back at least initially? I'm not sure. I think what So the first thing we'd we'd want to do is is confirm that we can uh land the ship safely on Mars.

And so that might be you would want to probably land two or three I think before sending people. And just confirm that that uh uh we we we can land safely. Um so you know, and actually on those missions we could we could obviously put um a lot of scientific instrumentation um that uh I would recommend putting the lower cost uh scientific mission stuff on the first mission.

Um but um uh we'll we'll certainly have propulsive landing very reliable on Earth as we've been able to achieve with the Falcon 9 booster. Um it it's now you know, knock on wood, so it's it's it's a it's not like it's quite normal for the rocket to land uh safely. And we'll we'll do the same with Starship. Um and and then um I'm not sure quite what would happen.

I mean, we might be working with NASA or um maybe NASA and and other uh you know, other countries to to send people to Mars. Um But I I I view this very much as um you know, the you know, 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?

Um and um I just think being a multi-planet species is is a tremendous uh risk mitigation for uh human civilization. Um and um as we know, eventually Earth will become If you wait long enough, Earth will become uninhabitable. So, um in the long run, we're obviously all dead.

But but I think the um you know, the the technology that we we develop uh in traveling from um Earth to Mars, I think it'll be just a very powerful forcing function for the improvement of space transport. You know, like the the initial boats that crossed the Atlantic and crossed the Pacific back in the sailing days were were really terrible. Um you know, um so you know, there there were often just planes sank.

And if if as once there was a reason to do uh large amounts of ocean trade, the the the the sailing ships the wooden sailing ships got dramatically better. Um And and so, but you you kind of have to have that forcing function. Um so, that That's what I think will happen and and and we'll we'll get much better at at space transport.

And I think this will also be very important if um you know, if there's like a potential uh Earth collision event from from some comet or something like that. Um you know, the the the asteroids we can predict fairly well, obviously, but um there's this massive cloud of of um of comets out there that uh you know, we we we don't know the situation. Um so, and they come in pretty fast.

So, there's always some risk of a comet like taking out a continent. You know, there's this place like they talk a lot about extinction events where that we, you know, almost all life was destroyed on Earth, but but they don't talk that much about the ones where well, it was just a continent.

There's 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 a lot of much attention. And and but if we've got large rockets that could potentially do something about that, then then that could be, you know, that could at one day save billions of people.

But we've we've got to have big rockets and much more advanced space technology in order to protect against the a comet coming in from, yeah, far away. Okay, thank you so much. Perfect. Thanks, Elon. Our next question will come from Arlene Spence. 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 here, but I 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? Well, I think being able to really, you know, have heavy duty science research on the moon and on Mars where you could really just go anywhere you want, Um to core samples anywhere you want.

Uh I think we'd learn a tremendous amount um uh as compared to having to send uh you know, fairly small vehicles with with limited scientific instrumentation um which is what we currently do for for Mars and and the moon. So, uh just I would have just having people there who can dynamically decide what they're going to do um and and really be able to analyze the whole history of the planet, I think we're learn a tremendous amount.

Um and uh yeah, um and that would obviously extend over time through at least the um the greater solar system. Um So, you know, I mean yeah, um I mean, I studied physics because I was just trying to find out what's what what's the universe all about? How does it work? Where did it come from? Why are we here? Um and um I actually kind of got sort of depressed at one point cuz I was like, man, this doesn't seem to be any meaning to life.

I it just seems to be like, you know, and then I made the mistake of like reading the German philosophers as a teenager and that that made it was quite depressing. Um But then but then I then I read uh Douglas Adams's Hitchhiker's Guide to the Galaxy, which is really a book in philosophy with the sky's the limit.

And he makes the point that you know, uh the question is harder than the answer and um and and really basically the answer is the universe and and uh we we we kind of need to figure out like what questions to ask about the answer that is the universe. Um and that's the question that's the hard part and then the answer is easier by comparison. Um So, so I'm like, I don't know, like like why are we here? How did we get here? Is this is this real?

Is this 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.

Um you know, um but uh yeah, I mean, I think it's and and and if we are able to at least be like um a multi-planet species within the solar our our solar system, then um then then hopefully we can develop the technology to send probes uh to um other star systems and eventually um maybe send send people, although that's tough, but we can certainly send ro- robots to um robot probes to all of all of the nearby star systems and um yeah, try to figure out what what what's what's the meaning of life and what's going on.

And are there any aliens out there? Where where are you guys? They searched up. Thank you, Elon. Sorry, go Do you have a Do you have time for a a question or two more? Uh yeah, as much time as you'd like. Oh, wonderful. All right. Um I do have one question from a from a board chair, um 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 5 to 10 times less? Sure. Um actually, I think it's not that it's not that far away. I think probably um 2 years from now. Uh so um our rate of progress on Starship is very rapid. Um and um like you said, we're we're actually getting ready to do our first local orbital launch attempt within the next uh few months.

We're expecting uh our license approval from the FAA uh around the end of this year, and then so that probably means uh a launch attempt in January or perhaps February. Um and then um we're 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, um, the the the engine build rate is currently the biggest constraint on, um, how many vehicles we can make, um, because there are currently 29, uh, engines on the booster and, uh, there will be 33 even at a higher thrust level. Um, so, um, that means Yeah, 33 engines per booster and these are big engines. These are, um, you know, our uh uh the Raptor 2 is a roughly uh, 240 ton thrust engine.

Um, so, we're talking like, you know, 5 or 600 thousand pound thrust engines. The Yeah, so, really quite quite intense. Um, I I in fact I'd say that the building the production system for Starship is much harder than the design of the Starship itself. Um, but we we have that in in progress and we intend to do, um, hopefully hopefully a dozen launches next year. Um, maybe maybe more.

Um, and and to if we're successful with it being a fully reusable, it means that we we build up the fleet just as we are with the Falcon 9 and the Falcon 9 booster which is reused. Um, we we lose the upper stage every time, but we almost always recover the booster.

So, um, so, basically we intend to complete like the test flight program next year, which means that it's probably ready for, um, for for valuable payloads that that are not kind of in the in the test not for testing basically, but actual real payloads, um, in 2023. So, quite soon. Great. Thank you so much. All right. Uh next next question from Ned Wright. Ned, I think you're still muted. Will we all be glad when we don't say that all the time?

Yeah, so it's um You have to preserve cryogenic propellant for 6 to 8 months to actually be able to land on Mars. And so I wonder what your plan is for that. Um yeah, so um the the the landing propellant for Mars would be in separate header tanks. Uh so these would be um spherical header tanks.

Uh for for Mars, they would probably be uh I might might be contained inside the main tanks uh or they would be up in the cargo section um but well insulated. So um it would it would actually have to um uh have extremely well insulated um header tanks for landing uh that are not the main tanks. So that that's what we'd have for for Mars. Great. Thanks. Uh Riza Wexler is the next question.

Yeah, so um changing topic to something that's happening before we have the possibility to uh be a multi-planet species. Uh I 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 And this is really going to significantly limit the science potential of the next generation of observatories if we don't have a course shift. So what role do you expect start uh SpaceX to play in working with astronomers and regulatory agencies to mitigate this?

Well, we SpaceX already works with um uh regulatory agencies and with the the um so with with the astronomers um uh and um generally what we see is the the the telescope um that is perhaps most sensitive to this is Vera Rubin. Um and uh we work directly with the the Vera Rubin team to make sure that uh their observations will not be affected by Starlink satellites.

Um and my understanding is at this point they are comfortable that it will not be uh an interference for Vera Rubin. Um they they have um uh there's a slight risk um of capacitive coupling between uh some of the uh basically um sensors there. Uh but this which can create ambiguity, but we we we're confident that uh we can work around that. Great. Thanks. Our next question comes from John Carris. Hey Elon, thanks uh for all your time today.

Appreciate it. Kind of going back to prior question about um long-term storage of cryogenics for whatever mission, but um um I realize or I believe that your architecture for Starship to go beyond lower Earth orbit to go to the moon has you know, cryo fluid transfers and things like that and Yeah. you long-term cryo fluid you know, cryo fluid storage, low boil-off and Those are not not easy problems. Yeah, yeah, no. And and So, not easy problems.

So, the question I have for you is is uh you know, what are your plans to to mature that technology but you before you have to rely on it for it to go to the moon like in a year or two? Well, um yeah, um so I mean, there's a lot of ways to address it. Um, by uh having a uh launching one one uh vehicle that is very well insulated, um, but does not return to Earth, effectively a propellant depot.

Um, so if you take a ship a Starship and you take take the the heat shielding off and replace that with uh thermal insulation like you know, multi-layer insulation of um that's just very very good um at um keeping things cold, um, then you could have one ship up there that uh is effectively just turns into a propellant depot. And and then you um send tankers up there to uh dock and transfer propellant.

Um, and uh and so it should be able to be there for a while and then whatever ship you want to go to the moon, you you go up and dock with the the the depot, uh transfer propellant and and off you go. So, that's that's the that's rough plan. We're pretty good at docking at this point. We've docked with the space station couple dozen times and the space station is a very difficult thing to dock with because we don't control both sides of it.

Um, and um so it's it's that that is a very challenging uh docking, whereas docking with our own vehicle is is comparatively easier. Yeah, but both of these technologies have really only been demonstrated on very very small scale. So, you're your scale's a lot larger and I think poses other problems. So, good luck in uh solving those. Yeah, I know I I I don't think we'll just sort of like, you know, it's not exactly a walk in the park.

Um, so like I think this is hard, um, but it is necessary and it's the only way um at least with that that I can think of with current physics to um to actually uh make things work. Um, and it obviously, you know, like um aerial refueling is is a is used quite a lot with with aircraft. Um, and so this is uh you know, taking that concept just doing it in orbit. Um, and um, so it like we're not we know that success is one of the possible outcomes.

Um, we're not breaking any physics. Um, you know, physics is the law and everything else is a recommendation. Um, so but it's it's at least in the set of possible success is success success is at least in the set of possible outcomes. Yeah. Great. Thanks very much. Uh, next question will come from Amanda Hendrix. Hi there. Um, so I'm a co-chair of the Committee on Planetary Protection.

And uh, our committee is concerned with preserving the validity of future uh, astrobiological experiments on Mars and other places in the solar system. Yeah. Searches for life extinct or extant. And I wonder if you can comment on SpaceX's planetary protection plans for Mars. Sure. Um, well, I mean first of all, it's not like we're launching to Mars really soon. I mean there's Mars is a ways off.

Um, and the you know, but there there is um, you know, fundamentally a choice to to be made which is um, are we going to try to be a multi-planet species? Um, uh, which would would mean that at least in one spot on Mars that there is human you know, human biology like that we will be you know, uh, we're pretty hard to avoid no no biology if you send humans there. They're biological creatures.

Um, but I I I don't think this is this is going to invalidate uh, research in the on the rest of the planet. I mean Mars is a big planet and so I and there've been uh, you know, rocks that have been knocked off of Earth and landed on Mars and that kind of thing.

So, uh But but yeah, I I think we'll, you know, there's a you wouldn't want to sort of spread biological debris all over Mars, but I think we will we will have to put at least somewhere if there are people going there. Um at at least in one spot. And and then just make sure we try to contain that and not have it sort of spread around. Um Yeah, and I guess it's same for the moon and and other places. Thanks. Thank you, Elon.

Um we'll just take a question or two more. Next question from Larry Paxton. Hi, thanks for your time. Um I have a question that was engendered by a remark you made in passing that I think is um very interesting. Which is where you said that um there's a window of opportunity for us to get off the planet.

And the question that occurred to me was uh you you followed that up with saying that you didn't know how long that window of opportunity would be open. Yeah. And there you mentioned in passing, of course, the traditional things like, you know, exogenous forces like uh 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 to uh 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 are we think are the most important that are unresolved yet.

I just wonder what you felt were the most important uh issues for us as the human race. Yeah, I mean, in general, I I you know, I've thought about this uh quite a lot. Um which is not to say that I've thought about it correctly, but I thought about it a lot. Um you know, and the you know, the the the the one of the bigger risks uh on Earth would be, you know, if if we that we need to transition to sustainable uh energy.

Uh even if uh one discounts the CO2 uh, capacity of the oceans and atmosphere, uh, eventually we'll run out of uh, hydrocarbons to burn and so we we need something that's long-term sustainable.

Um, so that that's that's what sort of um, you know, I kind of split my time between Tesla and SpaceX and so Tesla's um, trying to accelerate the advent of sustainable energy um, and that's you know, to uh, mitigate the the risk on Earth um, and then SpaceX is uh, intended to medi- you know, mitigate like longer-term risks um, that could potentially extinguish consciousness as we know it.

I mean, we got this sort of delicate candle of consciousness sort of flickering in the darkness here. Um, 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, um, I mean, I find the Fermi paradox is just an incredibly interesting question um, and um, I'm not sure who said it but the like there appear to be if if if there appear if there may there's either a lot of aliens or none.

Um, and equally each those ans- answers are equally terrifying. Um, so anyway, so I I think um, but with with respect to uh, near-term risks on Earth um, obviously sustainable energy um, and you know, potential non-linearities in uh, the CO2 in- uh, PPM in the atmosphere are are a concern. Uh, you know, if we start doing things like melt- melting the Siberian tundra and that kind of thing.

Um, um, I I'm probably less alarmist than most uh, on on on climate change. I I put myself in the in the moderate category on on climate change. I just think it's the the amount of inertia associated with the hydrocarbon economy is so gigantic that it it it um, um it will to require a long time to make that transition. And so, it's probably better to start it sooner rather than later.

And 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. That then with as for risks on Earth, um I mean, there's always good old nuclear Armageddon, you know? Uh that that's still one of the one of the things. Um That's That's not out of the question.

Uh there's still a lot of nuclear missiles pointed at us in in the US and many parts of the world. Um I I don't know what what quite that risk is, but it's not zero. Um Um I think there's there's maybe some counterintuitive risks or that people aren't don't put that much attention on. Um If you look at the birth rate trends, um they are the birth rate trends are very uh negative.

Um and so, um and in many many countries are are seeing population decline um with no end in sight. So, I think there's um Uh I think the the the the very low birth rate, I think, is actually quite a significant risk um but an an an underappreciated one. Um So, uh Yeah. Um And And for for population prediction, I would recommend taking uh things like the number of uh babies born last year and just multiplying that by the probable lifespan.

And if if if you do if you do that, you'll I think you'll see numbers that uh are very very bad for future population. Um and with an inverted demographic pyramid, so you've got a lot more older people and then fewer middle-aged people and then eventually just very few youngsters. Um And this will necessarily lead to uh resources uh being applied to taking care of the elderly instead of advancing science or advancing civilization.

Um I'm quite worried about that one um because I see no reversal of the trend um and um you know that that that would you know civilization will die with a bang or a whimper. That would be dying with a whimper.

Um Then there's obviously of course uh you know a pandemic with a with that that has that's that's like COVID but which has a much higher mortality um sort of a long you know high contagion highly contagious long incubation period high mortality uh type of um uh pandemic that's um really a risk um uh AI is I think maybe more of a risk than people realize.

Um Uh ironically the smart people tend to think AI is less of a risk um because they think that they're so smart um but actually we're just humans and we're quite dumb. We did you It's amazing we got this far frankly. Um So if you if you see the advancement of AI it's clear that AI will exceed human intelligence in every way if if these trends continue.

Um And the the list of things that the human mind can do better than AI is less and less every year. So you know hopefully that AI is AI is coupled to human will um but it might not be uh the you know the long-term goal of Neuralink is to achieve sort of better symbiosis with uh AI and with the kind of human mind.

Um in in the short term Neuralink I think it solve a lot of of of brain injuries and diseases and spinal injuries and that kind of thing, but long-term uh like cuz one of the things that I'm I'm getting quite esoteric here, but um the uh we're we're already a cyborg really in the sense that the our phones and computers are an extension of ourselves.

And and you could say we we arguably have um you know, sort of the sort of a the primitive kind of limbic system, the cortex, the higher higher thinking, and then we've got the tertiary layer, which is our which is silicon in the form of our computers and phones and everything.

Um the um we have already somewhat merged with computers, but the the the the issue we have is the um the communication rate, the bandwidth uh with the computers is low, especially output. If our output is two thumbs, uh that's, you know, we're we're talking maybe 10 bits per second or something like that. No, it's a or maybe maybe 100 best case. Uh it's a very slow uh output.

And as the intelligence of the computer grows, if that communication link remains very tiny, uh I think we will necessarily decouple from computers just because our rate of communication is very slow. And so, if if we can solve the IO bandwidth question and and by, you know, increase it by 1,000 or more, maybe a million, then the you could have human-machine symbiosis that is is much better. Um I I mean, that's at least one approach.

Um Let's see, what else is there? Um I mean, religious extremism, you know, if that that becomes if if that grows over time, uh religious extremism is is a is certainly a threat to um advancement of science. Uh so, depending on how how far that goes, that that that could be an issue. Um, Uh, what do you think? Yeah, it's a good one.

it's I will only add I think that this is a fundamental question because as you said, the Fermi paradox, um, there or 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? The great filters. Yeah.

Um, so, I I I I think at least one of the great filters is uh, does a civilization become multi-planetary or not? Um, yes. Yes. If a civilization does not become multi-planetary, then then eventually the sun's going to expand and and, you know, boil the ocean and that's game over.

So, and and and actually think about it from an egocentric standpoint, if Earth's been around 4 and 1/2 billion years, then it took us 1 and 1/2 billion years to get this far. Um, uh, well, prob- it may be as soon as another 500 million years and the sun might have expanded by enough by that time to boil the oceans potentially. If it's not 500 million years, it's not much beyond that.

Um, but which is basically means that if it took 10% longer for uh, you know, civilization to evolve, it would never have evolved. Right. So, that's an interesting one. Um, Elon, do you have time for one more question? Wonderful. All right. Um, Jill Dahlberg, please. So, let me just say I feel lucky that you are here. So, thank you. And not just here in our panel, um, 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?

Well, um a Tesla does produce solar power um and solar is actually there's a quite an amazing amount of of energy that reaches us from the sun. Um but um you know, I mean we really when you think about Earth is almost entirely solar powered. If it were not for the sun, we would be a frozen dark ice ball at 3° Kelvin.

Um so so apart you know, keeping us warm and not to be cold and frozen dark is pretty helpful and then the almost the entire ecosystem is solar powered. Um you know, plants are a solar powered chemical reaction and um you know, apart from chemo-trophs at the bottom of the ocean, it's basically you know, everything's solar powered. Um so really talking about just like a little bit of incremental power from the sun being used to power civilization.

Um the uh you know, as a sort of good rule of thumb is uh because you get about a kilowatt per square meter of solar energy. Um uh so then in a square kilometer there's a million square meters. So now you you've got a gigawatt of solar energy per square kilometer.

Um and so if you've got like uh 25% efficient panels and they're maybe uh 80% uh uh of the area is you know, panel of a you know, then you you've got like basically 200 megawatts per square kilometer of solar power. Um and so then if you say, well, okay, how much then you really won't need a large a very large area to power the entire United States with solar.

Um like a little corner of Utah or for Obviously you you'd prefer it to be distributed, but you can just say like, "Okay, how much is actually needed to power the US?" And it's you know, somewhere between a a square that's roughly 150 to 200 km on a side will power the entire entire United States. That So, it's really clearly no problem to power civilization with a um with a with with solar.

And then, of course, there's wind and um you know, I'm I'm actually pro-nuclear pro-vision-wise um and there's also hydro and geothermal. So, I I think we will solve Earth's energy needs um and and they are being solved. If you look at the growth of wind power and solar power, it's it's really has a very high growth rate. It needs to be paired with batteries in order to because the the intermittency of wind and solar.

But the combination of of solar plus battery will can completely solve all of of Earth's energy needs. In fact, for satellites that are in orbit, that's all they use is solar panels and a battery. And and what what is Earth but a large satellite? Sorry, I think you're you're on mute. Do you Do you want to follow up on that? Yeah, I was 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. Batteries. And battery. I like that. Thank you. It works great. Like because if we 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. Um yeah, it's just 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 of magnetically confined fusion, you could absolutely make it work. Um I 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 you we've got a giant fusion reactor in the sky that just shows up every day with and doesn't require any maintenance.

Um, so it's a low maintenance fusion reactor shows up every day. So, if if we just just catch the energy from, you know, where catch it and just keep us loving all this energy at us, just catch it with the photovoltaics and and store in the batteries and it'll that'll that'll solve for everything, basically.

Um, yeah, we're going to need a lot of batteries, but there's also like next question might be is there are we going to face some materials limitation with batteries and the the answer is definitely not. I think most of the vast majority of stationary storage will use an iron cathode lithium-ion battery. So, there's 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, it's basically everywhere. Um, so and and so you have a basically an iron phosphate cathode with a a graphite anode um, and lithium carbonate there's there's enough of that on earth to power many civilizations. Several or easily order magnitude larger civilization than ourselves could be powered with with the batteries that with battery materials that 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. Okay. That's wonderful. 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 Wooster is a member of the Space Studies Board and this is also the Board on Physics and Astronomy and um 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 uh the 7:00 p. m. hour on the East Coast or wherever you are. No problem. I will Well, well, thank thank you for the for the great questions and and I was honored to to speak to everyone. Thank you.

Thank you. Cool. Do we