YouSaid · the spoken record

Tim Dodd

lines on the record: 382
first: 2023-02-02
most recent: 2023-02-02
sittings or episodes: 1
sources: podcast

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“Actually, and then there's tap off expanders. Like, I mean, all of them kind of do the same thing, but you end up at some point spinning a turbine. You know, a turbine can take some of the heat energy and the pressure of an engine, and then that can be connected to a shaft to pumps. And those pumps can increase the pressure of the propellants and force it into the combustion chamber. Now, the difference between open cycle, closed cycle, full flow all those is what happens after the gas has flown through the turbine. So after you've used the turbine and spun up the energy, you know, spun up the engine, what happens to that gas? So in an open cycle engine, you basically have like a separate small rocket engine in a sense. It's a gas generator, they call it. And that will be used to create someone, you know, take a little, we'll say 10% of your propellant flowing to the”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“So ultimately, like we said, your ultimate goal is you want to get heat and pressure into an engine. So obviously at some point, you can either make really thick tanks of your rocket. You can get it so thick that you store the propellants in really, really high pressures. But obviously, that doesn't scale very well. At some point, your rocket's so heavy you can't even leave the ground or, you know, it's just so much of your mass is just literally the walls of the rocket. So at some point, people realize, hey, we could actually just pump the fuels and the oxidizer into the engine at a high pressure and increase the pressure through a pump. Now obviously a pump is going to require energy. You have to get that energy from somewhere. And again, at some point, people were like, well, rockets are, there's already rocket fuel here. We'll just use some of the energy from the rocket fuel to spin these pumps. So that would be considered like open cycle, closed cycle, full flow stage combustion cycle are ways to tap into the propellant.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“They're simple and easy, but these days, like, you know, you'll still see them kind of as traditionally boosters. Like they're used to just help get something off the ground or help give it a little extra boost. So the space shuttle famously had those two huge white solid rocket boosters attached to the orange fuel tank. Those are solid rocket propellants. Things like the Atlas V can have up to five smaller solid rocket boosters. There's very few rockets that use a pure, at least these days that use a pure solid rocket motor for its first stage. There still are, especially in China, there's a lot of startup rocket companies that kind of use just missile technology. They might use a variant of an ICBM that just use solid rocket fuel because it is very relatively easy to develop model rockets, use solid rocket motors and stuff like that. So they're still around, but they're just not as elegant and not as, yeah, not as used these days.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah, and the United States really is the only ones that, well, the only ones, I guess early on, because it was really just the Soviet Union versus the United States. The United States started to use solids pretty early on.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“But then if you get into hypergolics, you'll normally have nitrogen tetroxide, which is your oxidizer and some form of hydrazine for your fuel. There's solid rocket propellants, like solid rocket boosters, and those are actually pre mixed. Your oxidizer is inherently like baked, literally kind of baked into the sludge of fuel.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Enough to store in tanks. You know, it's a thousand times more dense when it's in a liquid than it is as a gas. RP1, which is basically kerosene, is a very common fuel. Another common fuel nowadays is methane, liquid methane, liquid hydrogen is another, it's the most efficient potential for the most efficient since it's one of the lightest molecules.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“So, really, I mean, fuels, there's kind of two terms. You'll generally hear the word propellant being used. It's anything that is used to propel a spacecraft or used in a rocket engine. So you have to have, you know, you can have a fuel. You have to have a fuel. You have to have an oxidizer. And you have to have a spark to actually get those things burning. And that's just a general law of like the universe. You have to have fuel and oxidizer and a spark. Now some fuels will by themselves spark like hypergolic fuels, but ultimately you're always left with some kind of fuel oxidizer and a spark. So the general ones used most often are rockets, liquid oxygen is kind of the king of, well, there's better oxidizers, but they're extremely, extremely hard to work with, like fluorine. But generally liquid oxygen, so you just chill oxygen down to its liquid state minus 183 degrees Celsius. So it can be dense.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Straight up, and the engines are pointing straight down. Pony end up flaming and down, you're fighting gravity. And so that's kind of your biggest enemy outside of the Earth's atmosphere too.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“We're lucky because if I think of it as 10% either way, like 10% harder, it'd be like we could still do it. With our current technology, we'd still be able to get stuff into orbit. Man, things like reusability and this commercialization, the success that we've seen in the last 10 years, we'd just be on tooth in a margins, I think. 10% easier and we would have been like, I mean, it's just like totally different. It's so much easier. It's like this big, you know, sliding scale and 10% in either direction we'd be either screwed or really happy as far as getting into space. So it's just hard enough that things like fully reusable becomes very, very, very difficult. I think it's completely achievable. We have all the pieces to make it achievable. It does not disobey any laws of physics. It does not disobey any, there's no hard stops. It's just very, very, very hard. And so ultimately, yeah, like on Earth, for the first bit of launch, again, when the rocket's pointing.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Basically, like how much can you convert is really the ultimate game? How much pressure and heat can we convert into thrust? Like that's really at the end of the day, that's what a rocket engine is. So you have to have a powerful enough rocket engine to actually lift the rocket and a rocket is mostly just fuel. It's like 90 plus percent just the weight of fuel. So you just have to lift the fuel that's going to take it into orbit.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“From point A to point B with a smaller pipe, it just has to go faster. So obviously, you can constrict it, but at some point, you actually get to a physical limitation, and that happens to be the speed of sound. Once it gets to the local speed of sound, you can then actually do the opposite. You actually expand it back out, and you're continuing to convert the pressure into velocity at that point, but it's now supersonic. And what's interesting is while you're doing that, you're actually cooling it down too. Each bit of that pipe that you're making wider and wider and wider, you're cooling down. So the more heat energy you have to work with, the more work you can actually do. So at some point, a hot, high-pressure rocket engine is the best source of, like, that's the ultimate amount of work you can do.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“And it's the majority of our atmosphere. It's more sparse. You can condense that down sort of a really high pressure bottle and then just literally shoot it through what's called a D-Lavel nozzle, which is something that chokes the flow a little bit, gets it to be, takes it and gets it into supersonic speeds. Once it's at supersonic speed, you actually can't choke it down anymore. You'll just constrict the flow of mass flow. You'll constrict the airflow. So you actually go opposite. You start making it wider. And once it's already at supersonic speeds, if you expand it and make it wider, it actually gets faster and faster. So at first, you know, when it's subsonic gas, you start shrinking, you can strict the flow, you know, it's actually speeding up just like, you know, a highway. If you go from, you know, any of these examples like a water hose, if you pinch it down, you want to flow the same amount of water from point A to point B through a smaller pipe, you can flow more water or the same amount of water.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah, ultimately a rocket engine converts high pressure and heat into kinetic energy. Like that's the only real job of a rocket engine is to take high pressure gas, hot, high pressure gas, very energized. There's a lot of energy involved and then literally turning that into molecules shooting in one direction, into kinetic energy. So yeah, what you do basically, you know, I mean, the simplest version of it is, of course, like famously a balloon. You take a balloon, you fill it up with air, you've got a pressure, you let go of it. Some of the air shoots out in a general direction-ish. You converted that pressure into kinetic energy. Now, if you start scaling that up, you know, you can continue to do something like that, like cold gas thruster would be kind of the most simple and easiest rocket engine to make would be a cold gas thruster. And all that is you literally just take air or specifically nitrogen because it's a little bit more dense than all the others.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“And not just Richard, but it improves their lives. We can look at every modern technology that is bestowed upon us today, air conditioning, electricity, internet access, fresh, clean water, running water, blah, blah, blah, 100 years ago, so many of the things that I listed either didn't exist or were only accessible by the ultra-wealthy. And it's through the innovation of technology and engineering and education that we were able to have it be that even someone below the poverty line and most of the developed world will have a good number of those things in their life. And that's just continuing to increase and continue to get better. So I think, yeah, that's to me in the grand scheme more important, but to each of their own.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Like being able to defend ourselves against asteroids. Like, if politics has their way and everything goes to crap and we don't even get to, you know, yeah, we're not going to be able to continue spaceflight and things like that. But like, I don't know. I just think there's better ways to do it and more uniting ways to do it than, you know, what feels like immature name calling sometimes, you know? Yeah.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“And this really isn't like anything about my personal politics or anything like that, but really just generally any of my friends that are like the first thing you hear about them in their day is something that happened in politics or something that some world leader is doing or not doing or saying and not saying I just don't find that to be the most important thing really I know that obviously that can affect a lot of people that has big real world consequences politics do But like I just and this is just me. I'm such a like who come together you know cheerio kind of guy that I just really think like you need something bigger than bickering about what you know what people said and did and what they voted on and all this stuff to really push humanity forward like I you know I know that politics and by extracting that social media can affect things like space flight and even our like planetary defense”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Personally, I just don't think that a social media, no matter what it is, I don't see that in a social media. And I don't see any sort of politicking as ever anything that's really ever uniting thing.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“I mean, personally, I just see that as a lot less important. And personally for me, inspirational than Starship and the work done at SpaceX and Tesla, to me, those were two very impactful and really, really just generally like, you know, they uniting, like, you know, something to rally around, get excited about. Rally and just like a future look forward to, you know, the idea of we're going to be building the world's most powerful biggest rocket ever and it's eventually going to be able to get humans on Mars for the first time. And we're going to transition the world into fully sustainable, awesome, just totally badass cars that do all these cool things. To me, those were like that brought a sense of unity and a sense of like, we can do this.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah, big time. And I think they really had to push, you know, if they hadn't done that, if they hadn't done that big push. Know we might only be now seeing a rocket stacked for the first time. It might be a lot more finished rocket, a lot more high fidelity, a lot more flight worthy rocket finished and stacked. But and they might not have to walk stuff backwards, but at the same time you do have to in this world to make rapid iteration rapid change and progress. So it's interesting. I don't know.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“It was just not done very well. They got a fully stacked Starship rocket out on the launch pad. You know, and it set, I think at some point you kind of have to stabilize some things enough and just say like, this is what we're doing to catalyze some things and say, now do this. It's almost like do it for fake, now do it for real, almost.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah, too many tornadoes. And I think it could almost be like you need someone to come back in and backfill almost because I've heard definitely stories of like, like, well, public is a good example would be last year or two years ago, 2020. Yeah, was that, yeah, or no? 2021, they did the first full stack of Starship Super Heavy. And they called it the big surge. All of a sudden, like thousands of SpaceX employees, you know, came down to Starbase and they just started building like you wouldn't freaking believe. I mean, it's just things going crazy, beeping. It was actually in the middle of that first interview I did with him, it was in the middle of that surge. There was like commotion like you wouldn't believe. You couldn't hardly talk because there's just so much going on. People just welding and blah, blah, blah, you know. Everything they did during that period was basically scrapped.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“100%. So I think the big mission, if we're measuring SpaceX's success on getting to Mars or not, I think they'd have a really hard time continuing to fulfill that drive without Elon at the helm. Now, I think there's a certain balance and beauty of Elon, specifically when it was Tesla and SpaceX, where Elon will go in, you know, have mild tornadoes around the factory and the engineering, you know, and like mix everything up and things get sometimes just totally thrown together, you know, and totally just like get it done just to get it done and start moving that direction. And then he'll leave and go to that same thing at space X or Tesla, vice versa. And then there's a little bit of a calm where people come back in and they fill in those gaps, you know, and I think that's kind of always been a pretty healthy thing, honestly, is like, I think if he is too focused on any one thing, it almost is like he'll spin.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Just super far forward, not taking note for an answer on things approach. And almost to his dismay, I think he is afraid of the sunk cost fallacy so much that it almost almost gets to the border of like being throw out everything before it's even, we've known it or not. At the same time, like it moves the needle so fast so far. So as far as the question of would SpaceX continue to like succeeding and be able to ultimately go to Mars without Elon, the Mars thing I think would probably be hard to uphold without. I think a lot of that drive for Mars is from Elon. It is maybe too fantastic for the average person and the average employee and maybe the average CEO that might step in to have a company's mission be to go to Mars.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Okay, the first thing I think to remind people is just how many brilliant people do work in each of these companies, obviously. Yes. You know, Elon's had some of the best teams assembled ever, just incredible people. He knows this. He will gladly tell people. And he says it often, like the amazing people, the amazing teams here. So it is important to remember that. That being said, like there is something to Elon's.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“It's looking, I think it's one of those things where you look at the curve. You look at like 10 years ago, that was ridiculous. Following this curve, if SpaceX goes from two years ago launching, I don't remember what it was, 40 times to 60 times to 100 times this year, is there amount? And if we just keep extrapolating that out, if they maybe not that exponential, maybe it goes more linear or whatever. What's 20, 30 years, like the amount of stuff we can put on orbit and the potential we have to do things likely. Now, I don't want to put a time frame. Yeah, I think, but you got to think we're increasing the number of launches. We're increasing the amount of things in space. We're increasing the amount of payload on orbit. That's probably not going to decrease anytime soon. And therefore...”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Landings of an orbital class rocket that's 45 meters tall, 3.7 meters wide. Like this thing is huge, weighs 20 metric tons even empty when it's landing. That thing's already huge. So seeing the success of that, I think people are now more like, well, okay, maybe there is actually the opportunity to be fully reusable. That's definitely probably the biggest constraint that I think has been questioned.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Know, and there's a large number of people that had the factual reasons to think that and do that. At the time they'd only landed like two rockets or something, you know, when they did that, or maybe three. It was a very small number. When they announced that actually they had just lost a couple months prior, they just lost MO6. So there was still this young blossoming company. And they come in and be like, we figured out reusability and now we're going to go full scale and make the world's biggest, most heaviest, most powerful rocket ever. And we're going to fully reuse it. And it's going to go to Mars. It was just pretty out there. Like it really was. Know it's all about perspective, but now again, we're coming up on 100 consecutive.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Definitely, I think the number of people that are saying that today is a small portion of those that were saying that type of thing five years ago. You know, when Elon did that announcement in 2016 for the ITS, it was very, very aspirational. And people were just like, yeah, right.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Is that going to be worth it? Obviously, SpaceX said, Yeah, I think we can actually develop this Raptor engine. So it's just interesting to see the things that have been looked at or even reusability. The space shuttle was reusable. The upper stage, you know, the shuttle itself, the orbiter was, you know, I mean, that thing was for all intents and purposes a reusable rocket. Now did it live up to its expectations, not necessarily. So it left a lot of bad taste in people's mouth on the ideas of reusability. So for SpaceX to kind of come back into the room and on the table and say, we're going to use a reusable rocket. Specifically, we're going to do a fully reusable rocket. You know, a lot of people are, even still today, a lot of people going. Yeah, you're not going to be able to do that.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“The hardest thing to Of remember is like how much stuff was developed in the 50s and 60s. You know, the concepts finally being utilized today were already literally done in the 60s. So, a lot of the things that SpaceX is doing isn't a novel concept per se. For instance, the Raptor engine utilizes the full flow stage combustion cycle engine. And that was already developed by the Soviets in the 60s for an engine called the RD-270. And it makes sense. Like on paper, 100% it makes sense because you're basically extracting the absolute maximum potential of the chemical energy in both propellants. And at the end of the day, like, you have to be dumb enough to say we're going to try using this thing because it's actually really complicated to do what they're doing. But at the same time, so are rockets. Like rocket engines are already stupid complicated. So adding 10, 20% more pain in the butt during the R&D if it's in the long, long, long, 20, 30 year existence or whatever, you know, like future of that engine.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“You can't have everyone doing that either. There has to be some humility of knowing that something is a hardened. Concept in a hard, you know, like, especially, I'm not an engineer. I don't do this stuff, you know, but I can imagine you sitting there having spent six years on a type of valve that perfectly manages crowd genic propellants or whatever. And someone walks in and says, why don't you just put a heater element in there, you know, or something that's something like because we've done that 40 times or whatever, whatever. I'm sure there are things like that that are very frustrating, but.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“It was last summer. I met up with some friends and like, hey, do you want to go on rag by this year? I'm like, it's like a week away. They're like, yeah, you want to go? I'm like, yeah. And so I did. And it was one of those moments where I was proud of myself because like I, it's easy to just be like, no. Know, I'm not readier. This is my constraint is like I'm not in shape. But, like, just question that, you know, and so I think when it comes down to questioning your own constraints, it's yes, even to that level of like, why do you question yourself on what you can and cannot do?”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“I would definitely say the biggest takeaway I've had from my times with Elon at SpaceX is the idea of questioning your constraints. He says that a lot, but he also does it a lot. There'll be times where you'll see him change on a dime because he's like rethinking of something in a newer different way. And for me, you know, I think we all put constraints on ourselves. We think about our own limits, you know, on things that we can or cannot do. And I think it's made me kind of question like, well, why am I, why did I say no, I can't do that? Or, you know, just off the top of my head, a good example. So in Iowa, I live in Iowa, or half the time or whatever. There's a bike right across the state of Iowa called Ragbray. And every year you just, you know, like thousands of people get together and they ride across Iowa.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Oh, yeah, yeah. There's a lot of, especially like around DM2, there's a lot of talks in the press conferences and stuff where you'd hear people say, This was a big, this is well outside of our comfort zone to work with SpaceX in this manner because we take this approach to things where X, Y, and Z in this way, the way we normally certify things, and we're not used to SpaceX like, well, let's just try it. and do something to a point. And so they said it ended up being fantastic. They loved working that way because it was just less paperwork almost and more just do. But at the same time, SpaceX, I think, even expressed, I don't remember if it was Hans K ⁇ nigsman or someone in a press conference said, well, we really liked having someone just double check us so that we're not doing something super stupid right before we test something, you know?”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Evolve it so quickly. Literally, like one after another was never really the same, and we're definitely seeing that with Starship now. You just can't even keep up with it, you know.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“I remember at some point That NASA, as they're leading up to flying humans for the first time for NASA, there's some talk that like we're going to do a design freeze because SpaceX does evolve and iterate so quickly. They were saying that it was leading, because especially at the time it was a mission called Amos 6 and they lost a rocket. They've only lost two rockets ever, really, as far as trying to get something to space for the Falcon 9, sorry. And the second one, AMO6, I mean, that was back in 2016. So it's been a long time. But at the time, you know, they're looking at flying humans in the near future. And it's like, if you guys keep tweaking this thing every time you take it out to the pad, there's going to be a problem, you know? And so there is some pressure from NASA to kind of slow down on that iterative process. But that is also why they were able to evolve the Falcon 9 to be what it is today is because they did.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“It's just so crazy because there's all these, like, I would just love to see the trade studies, you know, when you're like trying to figure out like, is this more important than this or this or this? And it's like, you change this one little thing and all of a sudden, you know, like all everything changes. It's just even the profile, like the launch profile, the trajectory of it. I mean, everything. Everything.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“At the end of the day, that is definitely the ultimate metric how much does one kilogram cost to orbit eventually. But it's so funny because spaceflight is just the ultimate, you know, it's the ultimate compromise. Every little thing, any variable can just change everything else. So you can tweak so many different things to get to different numbers and conclusions, you know, but even things like on your first stage when the rockets pointing straight up and the engines are pointing straight down, you're dealing more with the thrust weight ratio of the rocket. So how much thrust is it producing versus how much is gravity pulling down on it is actually more important metric than how raw efficient the engine is. So it's funny. Then in space, it's kind of the opposite. Thrust to weight ratio doesn't really matter. What really matters is the actual impulse, it's called her, like the nozzle escape velocity of the injection velocity of the how fast is the gas moving. It's like the more important number on orbit, but it's.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“That now as an index is. Well, and when you think about it, I don't know of any other company prior that had kind of tried to measure their performance of their engine, not and like thrust to weight ratio or like how efficient it is in specific impulse, but literally in like dollar to thrust ratio, like how much does this engine cost? How much thrust can it produce? And using that as a trade study instead of just pure metrics of, you know, because at the end of the day, like, okay, if it's cheaper and does, you know, X amount of work, even if it's less efficient, it can actually be better long term.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“What's there? Engines are relatively small number, which is easy for us. Yeah, the Merlin's evolved throughout time to be from like the Merlin to the Merlin 1 seed and the Merlin 1D to the Merlin 1D full thrust and all these other kind of tweaks of the same architecture. Kestrel ended with Falcon 1. They also have the Merlin vacuum engine, which is the upper stage engine for Falcon 9. Same relative system, but just optimized for vacuum so it has a much larger bell nozzle. There's the Draco thrusters, which you kind of can consider engines. Well, they are rocket engines, but they're just small. They're not like the orbital engines. There's these Super Draco engines, which are the abort thrusters on Crew Dragon capsule. And then nowadays they have the Raptor engine and the Raptor vacuum variant. But they've already had two versions of Raptor. We've already seen kind of the Raptor development engine. We've kind of seen like a Raptor 1.5 whereas kind of taking hints of the future Raptor, but now we're...”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Oh, yeah, it could absolutely be done. The hard thing at this point, because it's on an eccentric orbit, would be rendezvousing with it because you kind of have to be in alignment with its orbit to really line up well with it. But yeah, I mean, someday I don't see any reason why we couldn't at least send for sure an uncrewed Elon wanted to just fly a robot out there to check up on it and photograph it or something like we could that could be well within the realm of things.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah, it's orbiting the sun. It's orbiting the sun, and its orbit is basically between the Earth's orbit and beyond Mars. So I think of like 2.5 AU, if I remember right. So it's beyond Mars' orbit at its highest point, and it's back at Earth, kind of in its lowest point.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“So you can literally measure in like a yield of explosive power like you could TNT. You can take a look at how much propellant is left over at the time of the exposure. And Starship, what's flown so far, even though it's physically one of the largest flying objects ever, just with the upper state alone. They've not filled it more than like 10 or 20% full of propellant And so it actually hasn't been the failures have been really epic looking, big visual fireballs. But in terms of spaceflight, they're still pretty small explosions, believe it or not.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah, and lots of times it'd be like literally that they're building, you know, because at Starbase and what SpaceX is working on, like one foot is always in front of someone else's foot, and the arm is not knowing what the leg is doing sometimes. They will have someone working on, you know, they'll just be like, hurry up and build 40 of these tank sections. And you build the bulkhead and you build the downcomer and you build the header tank, blah, blah, blah. And all of a sudden, like, oh, we actually evolved that. We don't use that header tank now. So it's going to go on to this one. So they'll have parts of certain rockets built. And it's like, ah, literally scrap it. Like not scrap it in the joke term, but like literally just go scrap it. And they, so yeah, they just evolve and iterate so quickly.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“So far, the milestones we've seen, I'd say the first one would be the hop, they call it Starhopper, and it's basically a very rudimentary rocket, but it was the first time they utilized their new Raptor engine to produce thrust to fly something. It first flew like literally like three meters off the ground or something like tethered to the ground. Then it flew like 15, and then finally it flew 150 meters. And that was in 2019. And that was the first big milestone of Starship. And then after that, we saw SN5, SN6 kind of do the similar like 150 meter hops with a little bit more elegant systems, you know, proving out more of their tank building, proving out more of just subsystems. And then the big ones physically were in end of 2020 and early 2021 when they flew the SN8, 9, 10, 11, and 15.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah. And not just into space because, you know, there's been people that have done space flights with, you know, like suborbital hops, but going into orbit. And especially docking and rendezvousing with the International Space Station is a big deal. It's a whole until you really understand the physics involved and the scale involved with like just crossing the Karman line going straight up versus going into orbit. They're just completely different things almost.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah, I would say definitely the big ones, obviously, like any of the first, like the first flight of Falcon 1, first flight of Falcon 9, first time they went to the International Space Station, the first time they landed a booster. The first time they reused a booster, which is, I think, about six months after, no, it was a year after it was SES-10, 2017. It was the first time they reused one of those boosters. And that was a big milestone. Can we even, yeah, we recovered when we caught one, you know, it's like we got one now what? That was the first time they reflew one. Yeah, then flying humans was a huge one. DM2, Bob and Doug.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah. So they went from the cargo version of Dragon that flew about 20 times successfully to the International Space Station, except for that one CRS-7 where the rocket blew up and the capsule obviously didn't make it to the ISS. Then they went into the Dragon 2, which has two variants. It has a crew variant. So we just call it Crew Dragon. And then there's the cargo version of Dragon 2. And that's just an updated sleeker, sexier version of Dragon. And ironically it's heavier altogether. So you'll never see those cool returned launch site landing. The booster is coming back to land for CRS missions anymore like we used to, but they landed on the drone ship anyway. And yeah, that's been flying successfully. That's kind of the, so there's, yeah, Starlink, Dragon, Falcon 9, Falcon Heavy, and Starship system is kind of the whole SpaceX world, really.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“And that's what we see with Starship and Super Heavy. So the super heavy booster, the whole system, it's confusing. The whole system is kind of considered Starship, but technically the Starship is just the upper stage, which is also like the spaceship, which is also the upper stage, and then the booster itself is considered the super heavy booster. And that's what they've been working on. Publicly, it came out in 2016 as the time it was the ITS, the interplanetary transportation system. Later in, I think about the end of that year, 2017, it kind of became known as the BFR, the big Falcon rocket. Yeah. And then I think it was about end of 2018. They started calling it Starship. But that is where we're at today. And that's what they're working full steam ahead on.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source
“Yeah, realistically, the Falcon 9 evolved more or less kind of just got more powerful and a little bit longer and more capable. But nowadays they fly what's called the Block 5, even though it's like the eighth or ninth iteration of the Falcon Adam, but they call it Block 5. It's the one that has the black landing legs, the black interstage. They have a fleet of roughly 10 or so that are doing the majority of the legwork these days. And they're flying, you know, up to 15 times, I think, right now is the current booster leader. They're also recovering the fairing so the nose cone of the rockets are frequently, if not every time, being recovered. Same with, yeah, same with the booster for the most part. And the only thing being expended is the upper stage. And that's kind of where the Falcon 9 is ending. It really doesn't make sense to develop that infrastructure any longer. So they went with the next step, which is go even bigger physically. So they have more margin for upper stage reusability.”
2023-02-02 · Lex Fridman Podcast · #356 – Tim Dodd: SpaceX, Starship, Rocket Engines, and Future of Space Travel · IDENTIFIED FROM THE TRANSCRIPT · source