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Rocket Science Explained by Elon Musk

Rocket Science Explained By Elon Musk who founded Space Exploration Technologies, or SpaceX. His goal was to make rockets for space travel more affordable, with the ultimate goal of creating a colony on Mars. “What Elon did was very different. He didn’t just throw some play money in. He put in his heart, his soul and his mind.” Chapters: 0:00 Intro 0:15 Orbital dynamics in rocket science 4:25 Rocket stage separation 4:43 Why rocket stages need to land in ocean on a drone ship 6:43 Rocket control in vacuum (Nitrogen Jets) 7:30 Rocket control in air (Grid Fins) 9:01 Why reusability of rockets is important 11:46 Elon Musk about Interplanetary Space Travel 11:51 Elon Musk channeling Carl Sagan 's Pale Blue Dot 14:24 Why Elon Musk want to build a city on Mars in his lifetime Thanks for the inspiration to @SpaceX , @NASA and for music thanks to @newarta and @Happy Soul Music Library ​ Video sources used: Some SpaceX rocket landing footages: TED : The future we're building -- and boring | Elon Musk Elon Musk | Full interview | Code Conference 2016: Lex Fridman interview with Elon Musk: Elon Musk channeling Carl Sagan 's Pale Blue Dot elon musk,elon musk rocket science,elon musk rocket landing,spacex landing,elon musk motivation,spacex launch,learn rocket science,elon musk interview,spacex,rocket to orbit,rocket stage separation dynamics,orbital dynamics,spacex rocket reusability,drone rocket landing,water landing rocket,rocket grid fin,rocket nitrogen thrusters,falcon 9 booster landing,orbital class rocket,orbital class booster,elon musk rocket landing back on earth,spacex falcon 9


Elon Musk | CEO Tesla | Asperger's 0:15

There is a bit of an education process that's needed to understand orbital dynamics. Because a lot of people can confuse like, Why the heck are you landing or ship, landing a rocket in a on a ship in the ocean? That seems pretty inconvenient. And the reason is because that going up and staying up is actually about velocity horizontal to the surface. So there's a huge difference between space and or space and or an orbit, like space you could think of is like, say being the international waters boundary for the Pacific Ocean. Like if you go, you know, 100 miles offshore, you're technically out of coastal waters, now you're in the Pacific. So it's like, technically, you're in the Pacific. But, but it's but orbit is like circumnavigating the globe. It's a really giant difference. And the reason that things go up and stay up is because you're zooming around the earth so fast that your outward radial acceleration is equal to the inward acceleration of gravity. And so those balance out and you have a net zero gravity. So when you see the space station, the thing that's little little sort of counterintuitive is that the space station is actually zooming around the Earth at 17,000 miles an hour. Even though it seems like it seems really still, you know, but it's moving really, really fast. Right? for them perspective, a bullet from a 45 gun your handgun is, is is just below the speed of sound. So the space station is going more than 25 times faster than that. And that's what's needed actually to go up and stay up. And that's why that's why there's the term escape velocity, not escape altitude, there's no such thing as an escape altitude, there's only escape velocity, you need to be a certain speed to escape the gravity of the earth. Yeah, you can think of gravity as kind of a funnel in space time. So we're thinking like a coin funnel, like it really is very much like that in, you know, but it's obviously a sort of a four dimensional coin funnel. But if you if you spend a spin a marble or coin on the coin funnel, but when it's when it's far out, it's sort of spin slowly. And then as it gets closer, it spins faster and faster. And if you want, if you want, if you were to start at the bottom of the coin funnel, and you wanted to, to, to exit, you'd spin it horizontally, and it would it would spin out. And and that's really how you how you get to orbit.

Unknown Speaker 3:06

Yeah, so how does the gravity Well, it's like a funnel, why you want to land on the on a ship in the ocean. Because in order to get to orbit, you, all that matters is your horizontal velocity, your altitude is doesn't really matter. In fact, the the, the force of gravity at say, the nominal boundary of space, 100 kilometers, is almost exactly the same as it is on the surface of the earth. Is it like it's a few percent lower than, than the surface the earth. So in order to go up and stay up, the only thing that matters is how fast are you going horizontal to the surface. So you have that outward radial acceleration, or think of it like maybe like tetherball, or something like that, it's really, that outward acceleration is the thing that matters. And so when the rocket is going to orbit, the only reason it's going up is to get out of the thick part of the atmosphere, because that's at high velocity, that atmosphere is thick as molasses. And so it goes up very briefly, but if you look at a long exposure of the Rockets trajectory, you'll see it goes up but immediately curves over and starts going horizontal. And so, the, at the at the point at which the the point at which the stage is separate those two stages separation.

Unknown Speaker 4:40

The primary Bruce stage, which is the most expensive part of the rocket pointer, which that's that staging occurs, can be as high as Mach 10. But it's, it's so it's going away from the launch site, a 10 times the speed of sound.

Unknown Speaker 5:01

So in order to get back to the launch site, you would have to have enough fuel and oxygen to reverse out that velocity. And, and, and boost back all the way to the launch site. And you just don't have the physics of it doesn't really allow you to have that much. It's not about saving money on fuel or anything, it's just physically impossible. So because another sort of thing about, if you're, if you're in space is that there's nothing to react against. So like, whereas an aircraft can, can circle very easily because it's reacting against air in vacuum, there's nothing to react against. So the only way to go back the other direction is to apply just as much energy as it took you to go. If you want to go backwards, you have to fly just as much energy as took you to go forward. In fact, or twice as much, really, because you got to zero it out. And then you've got to land elsewhere. Yeah, So bottom line is this thing is doing an app yet Super 10 times, it may well be over the ocean, because the ocean covers most of the Oh, it's it's actually the point of separation, it's not that far away, it's maybe 100 kilometers away from the launch site, but it is going like hell, in the opposite, you know, away from the launch site. So the the only way to really land it is to have it continue on that arc that was to garch and then land far out to sea on a ship. That's that's pre positioned to a particular latitude and longitude very, very precise to within about a meter. And then the rocket will then go from vacuum through rarefied air at hypersonic velocity. And what so where does it when it's in vacuum, it has to obviously you can't use Aero surfaces, you have to use nitrogen jets to control the the attitude and position.

Unknown Speaker 7:05

So the first stage has already been a turnaround and you can see the nitrogen from our attitude control system helping guide it back

Unknown Speaker 7:16

and stave separation has been confirmed. And you can see the first stage they're whipping back, use the nitrogen thrusters.

Unknown Speaker 7:30

And then as it starts to encounter the air, we use grid phantoms because grid fins looked like sort of like a waffle. And as

Unknown Speaker 7:42

you guys have noticed, the grid fins have deployed on the side boosters as well as the center core. Those work to help guide the boosters back to a nice targeted soft

Unknown Speaker 7:51

landing. They work quite well across a wide regime from both very high velocity hypersonics through supersonic transonic and subsonic.

Unknown Speaker 8:03

Speed one transonic.

Unknown Speaker 8:08

So it's hard to it's hard to have Aero surfaces that work well across that entire regime. And then so once the air forces become high in the

Unknown Speaker 8:18

cape getting closer and closer, what a cool view. First stage is passing through the cloud layers right now.

Unknown Speaker 8:26

It uses the the four grid fins to sort of control its attitude and land itself. Yeah, it's controlling it's, it's controlling pitch, yaw, and roll with with the grid fins. And, and then once those grid fins will then position it to where it's fairly close to the ship. And then it will light in this case, three of the nine engines to arrest the velocity and then drop to one engine for precision rifle landing. Right. So why why is that important? Why has that this moment that important for you? Just a very tough engineering problem. In the last 12 months or so I've come conclusion that better can be solved. And I think SpaceX is going to try to do it.

Unknown Speaker 9:12

Falcon nine is essentially standing on the shoulders of Titans as they like to say and literature. We've built upon a lot of those lessons, the things that NASA has learned, we've taken that but use kind of a clean sheet of paper that says How can you build a rocket knowing that we want to do things that have not been done before?

Unknown Speaker 9:37

Well, so in order to reuse the boost stage, which is about 70% of the cost of rockets.

Unknown Speaker 9:44

For the first stage, it starts as engines backup. It flips itself around and the whole first stage is the entering the Earth's atmosphere and slowly making its way back down for a London on a gunship that is out in the Atlantic Ocean. Landing lakes deployed. And Falcon nine has landed to the woods cost is that how much? Well, I mean, it's sort of on the order of 30 to $35 million. Right. So you want to save that? Yeah.

Unknown Speaker 10:21

I mean, it's like I try to tell my team it's like, imagine there was a pallet of cash that was floating through the atmosphere. And it was gonna burn up and smash into tiny pieces. Would you try to save it? Probably yes. Yes. Okay. Yeah, that sounds like a good idea. Okay. So, so yeah, so we want to get it back. And that way. We don't have to make another one. Oh, my God. Sorry, this was landing legs. Touchdown. This configuration is about four times the thrust of this of the Saturn five moon rocket.

Unknown Speaker 11:47

Four times the thrust of the biggest rocket humanity ever

Unknown Speaker 11:50

created before? Yeah, yeah. I mean, in as one does, yeah. The universe appears to be 13 point 8 billion years old. birth, like four and a half billion years old. You're another half billion years or so. The sun will expand and probably back right the oceans and make life impossible on Earth. Which means that if it had taken consciousness 10% longer to evolve, it would never evolve at all. keeps them longer.

Unknown Speaker 12:30

And I wonder

Unknown Speaker 12:32

I wonder how many dead one planet civilizations that are out there in the cosmos. That never made it to the other planet and ultimately extinguished themselves or were destroyed by external factors.

Unknown Speaker 12:44

Probably a few

Unknown Speaker 12:46

channeling Carl Sagan. Look again at that dot. That's here. That's home. That's us.

Unknown Speaker 12:55

on it. everyone you love. Everyone you know, everyone you ever heard of every human being who ever was lived out their lives,

Unknown Speaker 13:06

the aggregate of our joy and suffering 1000s of confident religions, ideologies and economic doctrines. Every hunter and forager, every hero and coward, every creator and destroyer of civilization.

Unknown Speaker 13:18

Every Kingdom peasant, every young couple in love, every mother and father,

Unknown Speaker 13:24

hopeful child, inventor and explorer. Every teacher of morals, every corrupt politician, every superstar, every Supreme Leader, every saint and sinner in the history of SBC is left there, on a mote of dust suspended in a sunbeam. Our planet is a lonely speck in the great enveloping cosmic dark.

Unknown Speaker 13:48

In our obscurity, in all this vastness, there is no hint that hope will come from elsewhere. To save us from ourselves.

Unknown Speaker 14:01

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future to which our species could migrate. This is not true. This is Bob Marley.

Unknown Speaker 14:15

And I think Carl Sagan would agree with that he couldn't even imagine it at that time. What why Ilan, because this because why do we need to build a city on Mars with a million people on it in your lifetime, which I think is kind of what you said. You'd love to do. Yeah, I think it's important to have

Unknown Speaker 14:37

a future that is inspiring and appealing. I just think that they're like the happy reasons that you get up in the morning and you want to live like why do you want to live what what's the point what what inspires you what what do you love about the future? And if we're not out there if the future is not include being out there among the stars, and being a multi planet species, I find that It's incredibly depressing if that's not the future that we're gonna have

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