WEBVTT - Reusable Rockets 0:00:00.160 --> 0:00:07.160 Brought to you by Toyota. Let's go places. Welcome to 0:00:07.360 --> 0:00:14.880 Forward Thinking. Hey there, and welcome to Forward Thinking, the 0:00:15.080 --> 0:00:17.680 podcast that looks at the future and says the stars 0:00:17.720 --> 0:00:21.760 look very different today. I'm Jonathan Strickland, Laura, and I'm 0:00:21.840 --> 0:00:25.280 Joe McCormick Melancholy again. It's a two First. I told 0:00:25.320 --> 0:00:28.000 you in the last episode that was a bitter sweet. 0:00:28.200 --> 0:00:32.720 That was tribute, right, tribute. Yeah. Actually, now I feel 0:00:32.720 --> 0:00:35.360 like I need to like find some good Alan Rickman quotes, 0:00:36.800 --> 0:00:40.839 it's been a rough week. Wizards and Goblins. Man, Wizards 0:00:40.840 --> 0:00:43.919 and Goblins, got my slitherin sweater here though, So everything's 0:00:43.960 --> 0:00:49.159 doing okay. Yeah. So while we are mourning, we're grieving, 0:00:49.560 --> 0:00:54.120 we're also celebrating because one, we're celebrating great art that 0:00:54.240 --> 0:00:57.120 was left behind as artists themselves have passed away. But 0:00:57.120 --> 0:01:01.200 we're also celebrating because we're in an era of amazing 0:01:01.240 --> 0:01:06.039 technological and science development and we're witnessing it right now. 0:01:06.160 --> 0:01:09.039 Like we are in a time that is phenomenal for 0:01:09.120 --> 0:01:12.800 multiple reasons, and just one of those is that recently 0:01:13.040 --> 0:01:15.720 we've seen a couple of really cool demonstrations of a 0:01:15.760 --> 0:01:18.640 technology that we've been waiting for for a while. Uh, 0:01:18.680 --> 0:01:22.840 the idea of reusable rockets, rockets that can launch up, 0:01:22.880 --> 0:01:26.080 go into space, returned to Earth and land safely so 0:01:26.120 --> 0:01:29.800 that they could be used again after being refurbished. And 0:01:30.560 --> 0:01:32.200 this is a big deal and we'll talk about why 0:01:32.280 --> 0:01:34.800 in this episode. Yea. So, so the two examples that 0:01:34.840 --> 0:01:39.360 we've seen are are Blue Origin, which was the company company. Yeah, 0:01:39.360 --> 0:01:41.560 Blue Origins the company, and that was that's backed by 0:01:41.640 --> 0:01:45.520 Jeff Bezos of Amazon. Uh, and their rocket New Shepherd, 0:01:45.680 --> 0:01:49.120 which was the first one in late I think it 0:01:49.160 --> 0:01:53.000 was November, launched up, went to the edge of space. 0:01:53.040 --> 0:01:55.160 We'll talk about that in a little bit, and then 0:01:55.200 --> 0:01:59.800 returned to Earth and landed safely using thrusters to maneuver 0:01:59.880 --> 0:02:04.040 at self and land upright. And then uh, SpaceX would 0:02:04.040 --> 0:02:06.640 be the other one, and they launched a Falcon nine 0:02:06.680 --> 0:02:09.920 which actually delivered a payload into lower Earth ormit because 0:02:10.960 --> 0:02:15.560 SpaceX does that. Yeah. Yeah, it was a payload that 0:02:15.600 --> 0:02:18.320 had some satellites in it. So now I should mention 0:02:18.360 --> 0:02:20.400 that the Falcon nine, it was the first stage that 0:02:20.480 --> 0:02:23.400 returned to The Falcon nine is a two stage rocket. 0:02:23.400 --> 0:02:25.480 We'll talk more about that a little bit later too. 0:02:26.000 --> 0:02:29.640 But in both cases, this is really impressive display of 0:02:29.960 --> 0:02:34.120 technological and engineering expertise. Now, if you're sitting there thinking, 0:02:34.120 --> 0:02:37.160 wait a second, what's so great about that? I thought 0:02:37.240 --> 0:02:40.520 all the spacecraft we sent to space typically returned. Isn't 0:02:40.520 --> 0:02:42.920 that sort of the point? If they if they're especially 0:02:43.000 --> 0:02:45.960 for crude space missions, don't they come back? Here you 0:02:46.000 --> 0:02:49.760 need to understand the distinction between the spacecraft or the capsule, 0:02:49.880 --> 0:02:54.079 for true, and the rocket. That's true. I'm being very 0:02:54.160 --> 0:02:56.880 loose with the terminology, but yes, the rocket, the vehicle 0:02:57.400 --> 0:03:01.160 that delivers the spacecraft up into space, is what we're 0:03:01.200 --> 0:03:05.560 really talking about here. And the situation with rockets today, 0:03:05.800 --> 0:03:08.320 I don't know, it seems kind of wasteful. It's like 0:03:08.440 --> 0:03:11.320 if you decided, hey, I'm gonna cook dinner, and in 0:03:11.400 --> 0:03:14.600 the process of doing so, you destroyed every piece of 0:03:14.639 --> 0:03:17.440 equipment in your kitchen that you used to make dinner with, 0:03:17.639 --> 0:03:19.880 like the whole kitchen. Basically, like you just at the 0:03:20.000 --> 0:03:22.480 end of when by the time it's done, your stove 0:03:22.560 --> 0:03:25.560 is gone, your fridges, pots and pans in the trash, 0:03:26.000 --> 0:03:28.680 Your you know, knife, you're going in the trash. You're ruined. 0:03:28.840 --> 0:03:31.119 The example I gave is imagine that you are going 0:03:31.160 --> 0:03:33.200 to go on a family road trip and you buy 0:03:33.240 --> 0:03:35.640 a brand new car, and then you go out to 0:03:35.720 --> 0:03:38.160 Wally World, and then you just leave the car there 0:03:38.320 --> 0:03:41.640 and you uber it back home, and your car you 0:03:41.680 --> 0:03:44.160 never get to touch that car again. That car is gone. 0:03:44.200 --> 0:03:45.720 So every time you take a road trip you have 0:03:45.760 --> 0:03:48.800 to buy a new car. That sounds expensive. You can 0:03:48.800 --> 0:03:50.480 get up there. I mean, you know, it depends on 0:03:50.480 --> 0:03:53.960 your taste of vehicle. I being a luxurious type. It's 0:03:54.680 --> 0:03:57.160 it starts to rack up after eight or nine trips. Sure, 0:03:57.200 --> 0:03:59.680 And as you can imagine, launching things into space is 0:04:00.640 --> 0:04:03.080 even as cheap as going to Wally World. No, it's 0:04:03.160 --> 0:04:06.840 actually a tad more expensive. Uh yeah, So we wanted 0:04:06.880 --> 0:04:10.480 to talk today about the concept of reusable rockets. Why 0:04:10.560 --> 0:04:13.480 is that a big deal? And to really understand that. 0:04:13.560 --> 0:04:15.920 I thought it'd be kind of interesting because that's the 0:04:15.920 --> 0:04:18.360 way I think, to have a rundown on the basic 0:04:18.400 --> 0:04:21.240 physics of rocketry, so we can understand what is going 0:04:21.279 --> 0:04:23.640 on when we're sending a rocket up into space. This 0:04:23.680 --> 0:04:27.840 is particularly important because New Shepherd and Falcon nine are 0:04:27.839 --> 0:04:31.600 two very different approaches right. One thing you should keep 0:04:31.640 --> 0:04:34.160 in mind, of course, is where those two names come from. 0:04:34.279 --> 0:04:37.880 New Shepherd named after Alan Shepherd, the first American to 0:04:38.040 --> 0:04:41.239 make it into space. Falcon nine named after Star Wars 0:04:41.320 --> 0:04:46.159 the Millennium Fall. So, uh, those two are are quite different. 0:04:46.400 --> 0:04:48.719 And it's also a really good look into the minds 0:04:48.720 --> 0:04:51.400 of Elon Musk and Jeff Basis. Yeah, I would, I 0:04:51.440 --> 0:04:54.520 would agree with that, but this this is uh, you know, 0:04:54.560 --> 0:04:56.840 we'll talk a little bit about how those two are 0:04:56.960 --> 0:05:01.160 very different as we move along. So rockets work because 0:05:01.400 --> 0:05:04.960 of fundamental law of our universe actually collection of laws 0:05:05.000 --> 0:05:08.040 of our universe that we understand it. Yeah, if they 0:05:08.040 --> 0:05:11.160 weren't true, we wouldn't be sending stuff into space, right, 0:05:11.600 --> 0:05:14.280 And uh, those laws were first explained in a book 0:05:14.400 --> 0:05:20.840 called the Philosophia Naturalists Principia Mathematica by Isaac Newton, Sir, 0:05:22.920 --> 0:05:26.719 pardon me, sir Isaac Newton. And in that work Newton 0:05:26.760 --> 0:05:30.000 framed his observations of physics and frame them in the 0:05:30.040 --> 0:05:33.680 form of basic laws of motion. And there are three 0:05:33.680 --> 0:05:36.440 basic laws that we have to really look at. And 0:05:36.480 --> 0:05:39.239 the first is that objects at rest remain at rest 0:05:39.279 --> 0:05:41.719 and objects in motion remain in motion, moving in a 0:05:41.800 --> 0:05:45.560 straight line at a steady speed unless acted upon by 0:05:45.560 --> 0:05:49.440 an unbalanced force. Meaning an outside force of some sort. Right, 0:05:49.520 --> 0:05:52.479 So a ball only stops rolling along the ground because 0:05:52.480 --> 0:05:55.919 of friction. It doesn't stop rolling because things naturally slow 0:05:55.960 --> 0:05:59.320 down over time, Right, it would just continue for infinity 0:05:59.440 --> 0:06:05.040 if in fact that friction wasn't present, or or if 0:06:05.080 --> 0:06:07.560 it ran into something else in the change direction, obviously 0:06:07.600 --> 0:06:09.960 that would be difference, or maybe went through a gravitational 0:06:10.040 --> 0:06:14.160 field that caused some attraction. Yeah, but again, so when 0:06:14.160 --> 0:06:18.000 it encounters an unbalanced force, given no unbalanced forces, given 0:06:18.000 --> 0:06:21.239 only balanced forces. Yes. Also, we we wanted to note 0:06:21.240 --> 0:06:24.880 a thing about the terms rest and motion. Yeah, they're 0:06:24.880 --> 0:06:29.400 relative terms, so it all depends upon your point of reference. Right, 0:06:29.480 --> 0:06:33.000 So some of it can be a little counterintuitive. If I'm, 0:06:33.120 --> 0:06:35.520 for example, sitting on a train and the train is moving, 0:06:35.760 --> 0:06:38.719 Am I at rest or my in motion? Well, we 0:06:38.760 --> 0:06:42.320 would describe me as being at rest because compared to 0:06:42.320 --> 0:06:45.320 my surroundings, I eat the train, the physical train that's 0:06:45.360 --> 0:06:48.279 around me, I'm not moving. I'm sitting down, I'm sitting 0:06:48.279 --> 0:06:49.960 in a seat. Now, if I were to get up 0:06:50.200 --> 0:06:52.240 and walk in that train, then I would be in 0:06:52.279 --> 0:06:56.360 motion because according to my surroundings the train I am 0:06:56.360 --> 0:06:59.479 moving around compared to that the train itself is in 0:06:59.560 --> 0:07:03.520 motion because it's moving relative to the surroundings the countryside 0:07:03.560 --> 0:07:05.480 or tunnel or whatever the heck, the train happens to 0:07:05.520 --> 0:07:12.920 be going around, so it's all relative. Yeah, so that's 0:07:12.920 --> 0:07:16.480 important to remember. Unbalanced force is referencing the sum, total 0:07:16.680 --> 0:07:20.040 or net force exerted on an object. So I used 0:07:20.040 --> 0:07:22.000 a sandwich on a table because I wrote this note 0:07:22.080 --> 0:07:25.560 shortly before lunch and I was dreaming of sandwiches. Hungry 0:07:25.560 --> 0:07:28.120 notes are sandwich notes, Yes, So a sandwich on a 0:07:28.160 --> 0:07:31.119 table is an example of an object under balanced force 0:07:31.160 --> 0:07:34.440 because gravity is pulling down on that sandwich, but the 0:07:34.480 --> 0:07:39.720 table is giving equal force upward, keeping the sandwich on 0:07:39.760 --> 0:07:42.000 the table. It's not pushing too hard because we're pushing 0:07:42.000 --> 0:07:44.360 harder than the sandwich would jump off the table. Right. 0:07:45.800 --> 0:07:47.920 This is a really great analygy to be an amazing 0:07:47.960 --> 0:07:50.560 table would be an amazing table, but it's not happening. 0:07:50.560 --> 0:07:52.960 It's just it's exactly a balanced force. Now, if you 0:07:52.960 --> 0:07:57.200 can buy this table from you, this is a metaphorical table, 0:07:57.320 --> 0:07:59.720 So the answer is yes, I will sell it. Uh, 0:08:00.400 --> 0:08:04.360 But if you were the table, I am interested in 0:08:04.400 --> 0:08:06.920 your sandwich table, and I wish to subscribe to your newsletter. 0:08:07.120 --> 0:08:09.080 If you were to pick up the sandwich, you would 0:08:09.120 --> 0:08:13.480 introduce unbalanced force because you would be actually counteracting gravity. Further, 0:08:13.560 --> 0:08:16.640 you would have to use enough force to counteract the 0:08:16.640 --> 0:08:19.320 poll of gravity to lift the sandwich higher than its 0:08:19.680 --> 0:08:23.480 current height on the table. So what we're really talking 0:08:23.520 --> 0:08:26.760 about here is is two different scenarios in which forces 0:08:26.800 --> 0:08:30.200 can be balanced. Yes. Yeah, So if an object does 0:08:30.280 --> 0:08:33.120 at rest, the forces on it are balanced, and that's 0:08:33.160 --> 0:08:36.840 that's without question, right, If an objects at rest, by definition, 0:08:37.600 --> 0:08:41.400 the forces are balanced. If an object is moving, then 0:08:41.440 --> 0:08:45.160 it could still have balanced forces. If it's moving in 0:08:45.160 --> 0:08:48.280 a straight line and it's moving at a constant speed. 0:08:48.679 --> 0:08:52.040 If it's speed changes or its direction changes, that's a 0:08:52.160 --> 0:08:56.079 change and acceleration that is indicative of an unbalanced force 0:08:56.120 --> 0:08:59.800 being applied to this object. So that's covering just the 0:08:59.800 --> 0:09:02.360 first law of motion. The other two are pretty easy 0:09:02.400 --> 0:09:05.240 to remember. Second law of motion states that force is 0:09:05.280 --> 0:09:09.560 equal to mass times acceleration. Keeping mind, acceleration is not 0:09:09.600 --> 0:09:12.240 just speed like I said, it's it's a change in 0:09:12.360 --> 0:09:16.199 speed or direction because it's a vector quantity. And then 0:09:16.240 --> 0:09:18.240 you have the third law, which is for every action 0:09:18.280 --> 0:09:20.959 there is an equal and opposite reaction, And that's really 0:09:21.000 --> 0:09:24.400 the rocket law right there. Yeah, all three of these 0:09:24.440 --> 0:09:28.200 are are applicable. But yeah, but but the rocket would 0:09:28.240 --> 0:09:30.439 not go anywhere if it weren't for the fact of 0:09:30.480 --> 0:09:33.480 that third. That's the key to the propellant idea of 0:09:33.559 --> 0:09:37.040 rocket tree. So when we look at rockets, a rocket 0:09:37.040 --> 0:09:38.920 at rest is going to require a certain amount of 0:09:39.000 --> 0:09:41.839 unbalanced force for it to lift off of a launchpad. 0:09:42.120 --> 0:09:44.920 You know, you've got this big, massive, heavy thing sitting 0:09:44.960 --> 0:09:48.439 on a un a really big sandwich. Yeah, an enormous 0:09:48.480 --> 0:09:53.240 sandwich sitting on a really big tape. Because the moon 0:09:53.360 --> 0:09:57.080 looks very hungry, yes, and shouldn't we treat it once 0:09:57.120 --> 0:10:00.120 in a while. So this unbalanced force has to be 0:10:00.200 --> 0:10:03.560 greater than the forces pulling it downwards. So it has 0:10:03.600 --> 0:10:07.000 to be greater than gravity. And uh so with rockets 0:10:07.080 --> 0:10:10.240 we call that unbalanced for something specific, we call it thrust. 0:10:10.720 --> 0:10:13.320 So a rocket has to have enough thrust to lift 0:10:13.400 --> 0:10:15.439 off of the launch pad. If it doesn't, then it's 0:10:15.440 --> 0:10:18.320 not going to go anywhere. Even if you're shooting flames 0:10:18.320 --> 0:10:21.720 out the back of this rocket. If it's not enough thrust, 0:10:22.040 --> 0:10:24.680 it will just be a flamethrower firing at the launchpad. 0:10:25.280 --> 0:10:27.720 And gravity isn't the only thing that's that's in play 0:10:27.760 --> 0:10:29.680 here exactly. There are a couple of other things to 0:10:29.720 --> 0:10:33.120 keep in mind. So there's a drag, which actually is 0:10:33.160 --> 0:10:35.320 you know, sort of air resistance. Really yeah, yeah, because 0:10:35.320 --> 0:10:37.760 as we have said many times before, the air around 0:10:37.840 --> 0:10:42.040 us is not open and clear. It's soup particle soup. Yeah. 0:10:42.080 --> 0:10:44.440 If it were otherwise, we'd be in a vacuum and 0:10:44.720 --> 0:10:47.760 that would suck for us. We wouldn't exactly like a hoover. 0:10:48.040 --> 0:10:52.280 It would suck for us. I wish you could see 0:10:52.360 --> 0:10:55.040 the little laugh that Laura. What was great was Laura 0:10:55.480 --> 0:10:58.560 half laughter that almost came out. There was the moment 0:10:58.600 --> 0:11:01.240 where where she wasn't sure where I was going, and 0:11:01.280 --> 0:11:03.440 then there was the moment where she's like, on, man, 0:11:06.600 --> 0:11:08.640 I think I probably make around to you a lot. 0:11:09.160 --> 0:11:13.440 It's you're not the only person I inspire that. But 0:11:13.440 --> 0:11:15.560 at any rate, so as long as a rocket is 0:11:15.640 --> 0:11:19.600 within Earth's atmosphere, it has to deal with the drag, right, 0:11:19.640 --> 0:11:22.200 It's gonna deal with this air resistance, which is part 0:11:22.200 --> 0:11:24.360 of something that like, when we think of air resistance, 0:11:24.360 --> 0:11:26.640 you're probably thinking, well, that's got to be minor compared 0:11:26.679 --> 0:11:30.120 to gravity. I'm not saying it's more powerful than gravity, 0:11:30.120 --> 0:11:32.760 but it's something that as a rocket scientist you have 0:11:32.920 --> 0:11:36.280 to take into account. Otherwise you might not be developing 0:11:36.280 --> 0:11:40.760 a rocket engine that provides enough thrust to escape Earth's gravity. Actually, 0:11:40.800 --> 0:11:44.040 to escape ears gravity entirely, I mean not just going 0:11:44.080 --> 0:11:47.520 into orbit, but to actually leave Earth's gravity, you need 0:11:47.600 --> 0:11:50.400 to be going at a speed greater than eleven point 0:11:50.600 --> 0:11:53.640 one eight six kilometers per second or six point nine 0:11:53.720 --> 0:11:57.240 five miles per second. Wait, that's really fast, super fast 0:11:57.280 --> 0:12:02.400 for seventy kilometers per hour or thousand twenty three miles 0:12:02.400 --> 0:12:05.680 per hour. I know that's true, but you don't think 0:12:05.679 --> 0:12:08.800 about that when you watch a rocket take off because 0:12:08.840 --> 0:12:11.719 it just doesn't look like it's going that fact, well, 0:12:11.760 --> 0:12:14.800 at the point where it's leaving the ground, it's not 0:12:14.880 --> 0:12:18.000 going that fast exactly constantly accelerating. And then, of course, 0:12:18.040 --> 0:12:20.720 once you get outside the air atmosphere, you're no longer 0:12:20.800 --> 0:12:24.480 dealing with the drag. And also the further out you go, 0:12:24.559 --> 0:12:27.760 the less you have to worry about gravity. And the 0:12:27.800 --> 0:12:30.560 mass of the rocket itself is changing, right, because you've 0:12:30.600 --> 0:12:32.720 got the mass of all the fuel inside the rocket. 0:12:33.160 --> 0:12:37.439 As you burn that fuel, that mass starts to decrease, 0:12:37.800 --> 0:12:41.760 you need less force to accelerate it, right, because forces 0:12:41.800 --> 0:12:45.400 mass times acceleration um. As the mass goes down, it 0:12:45.520 --> 0:12:48.920 actually is easier to accelerate, right. And that's why multi 0:12:48.920 --> 0:12:53.040 stage rockets are so interesting, because you can jettison part 0:12:53.200 --> 0:12:55.640 of the rocket you had used to get up to 0:12:55.679 --> 0:12:57.720 where you are at that point of that altitude. Right. 0:12:57.760 --> 0:13:00.280 That's what we talked about earlier, like throwing your pots 0:13:00.280 --> 0:13:02.520 and pants in the trash as you're done with them, right, 0:13:02.559 --> 0:13:05.520 and then the second stage you light up, and the 0:13:05.559 --> 0:13:10.600 second stage can then accelerate the smaller mass of the 0:13:10.720 --> 0:13:14.680 rocket plus spacecraft, uh, much easier than it would if 0:13:14.760 --> 0:13:17.600 the first stage were still attached, because then you would 0:13:17.600 --> 0:13:21.000 have more mass to deal with. So that's that's interesting too. 0:13:21.440 --> 0:13:24.200 So the way that this thrust is generated is through 0:13:24.600 --> 0:13:29.680 propellant through burning fuel. Essentially, you're creating very hot, very 0:13:29.840 --> 0:13:34.040 rapidly expanding gas and you're directing it through a nozzle. Yeah, 0:13:34.280 --> 0:13:36.600 I mean, one thing we should specifies that it's kind 0:13:36.640 --> 0:13:39.959 of different than when we usually think about burning fuel. 0:13:40.160 --> 0:13:43.760 We we're thinking about like internal combustion engines or something 0:13:43.800 --> 0:13:47.000 like this. A rocket literally works by throwing mass out 0:13:47.040 --> 0:13:49.839 the back. Yeah, it's and that mass is in the 0:13:49.880 --> 0:13:52.199 form of gas, and you would think, oh, gas doesn't 0:13:52.240 --> 0:13:54.400 have a whole lot of mass to it. Well, it's true, 0:13:54.440 --> 0:13:59.520 but it's coming out at an incredible rate. Yes, So 0:13:59.559 --> 0:14:02.760 remember forces mass times acceleration. If that gas is coming 0:14:02.760 --> 0:14:07.480 out at an incredible acceleration, then the fact that it's 0:14:07.520 --> 0:14:10.280 small as far as mask goes doesn't matter so much, 0:14:10.440 --> 0:14:14.080 right though, I also think the total escaping mass that 0:14:14.120 --> 0:14:17.280 comes out the back of a rocket is pretty significant, 0:14:17.280 --> 0:14:19.560 even though it's gas over the over the length of 0:14:19.560 --> 0:14:23.600 a launch, definitely, But at any given instant, the amount 0:14:23.640 --> 0:14:27.240 of gas that's escaping that mass is tiny compared to 0:14:27.440 --> 0:14:31.120 the rocket plus spacecraft, right, But the acceleration is so 0:14:31.200 --> 0:14:34.760 great that it's enough to counteract gravity. So, in other words, 0:14:34.760 --> 0:14:36.640 when you watch a launch and you see that kind 0:14:36.640 --> 0:14:41.000 of slow lift off, that's because you've got this huge 0:14:41.080 --> 0:14:46.880 mass undergoing a relatively small amount of acceleration compared to 0:14:47.360 --> 0:14:52.880 the tiny mass of the gas particles undergoing massive acceleration. Now, 0:14:52.880 --> 0:14:55.920 I have another physics question. Has anybody ever done the 0:14:55.960 --> 0:15:00.000 math to figure out how much it changes the position 0:15:00.040 --> 0:15:02.160 shin of the orbit of the Earth every time you 0:15:02.200 --> 0:15:04.400 have a rocket to pitch against the Earth to leave. 0:15:04.520 --> 0:15:09.880 Orbit pushes back, Earth pushes back, So you know, you 0:15:09.920 --> 0:15:13.080 shove Earth, Earth shoves you. Then it goes to your family. 0:15:16.800 --> 0:15:20.280 Another reason to go treat the moon. The moon never 0:15:20.320 --> 0:15:25.440 did nothing to anybody, well werewolves, but other than them. 0:15:26.080 --> 0:15:29.960 So obviously, when you are making your plans to launch 0:15:30.000 --> 0:15:33.320 your rocket, it's not just the mass of the rocket 0:15:33.360 --> 0:15:35.360 and spacecraft you have to take into account. You also 0:15:35.360 --> 0:15:37.200 have to take into account the mass of the fuel 0:15:37.600 --> 0:15:40.200 that you're including, right, So this gets a little more 0:15:40.240 --> 0:15:41.880 complicated because then you think, all right, well I need 0:15:41.920 --> 0:15:45.560 to add enough fuel to get to this particular altitude, 0:15:45.680 --> 0:15:48.400 more fuel to pay for the fuel exactly right. So 0:15:48.440 --> 0:15:51.680 then you know, it's interesting, Joe, because before we went 0:15:51.720 --> 0:15:53.840 into the studio, in fact, a couple of hours ago, 0:15:54.400 --> 0:15:57.560 you had mentioned it's really cool that we live on 0:15:57.600 --> 0:16:01.680 Earth because Earth has properties that allow rocketry to even 0:16:01.800 --> 0:16:04.720 work here. Yeah, we actually got a really good piece 0:16:04.760 --> 0:16:07.280 of listener mail about this one time on Stuff to 0:16:07.320 --> 0:16:09.280 Blow Your Mind, the other podcast that I do with 0:16:09.400 --> 0:16:12.720 Robert Lamb and Christian Seger, and this listener wrote in 0:16:12.760 --> 0:16:16.320 to talk to us about about how we're in a 0:16:16.400 --> 0:16:18.960 nice position on Earth that you know, we can build 0:16:19.120 --> 0:16:21.640 rockets that can escape Earth's gravity. But if we lived 0:16:21.680 --> 0:16:25.640 on a planet that had a more difficult to escape gravity, well, 0:16:25.680 --> 0:16:27.880 I mean, what would we do. Yeah, Because if you 0:16:27.960 --> 0:16:30.520 can't find fuel that has the energy density that you 0:16:30.560 --> 0:16:33.680 need and is able to release that gas at an 0:16:33.720 --> 0:16:37.320 acceleration that's going to counteract the effect of gravity on 0:16:37.480 --> 0:16:41.480 your mass. In this case of rocket, you're stuck. Yeah, 0:16:42.600 --> 0:16:45.720 technological civilization that just can't get off the surface of 0:16:45.760 --> 0:16:48.480 the planet, which is entirely possible depending upon the gravity, 0:16:48.600 --> 0:16:52.160 right or not just the gravity, but also which elements 0:16:52.240 --> 0:16:58.240 are commonly available to turn into fuel, although for ygen 0:16:58.480 --> 0:17:01.240 not uncommon. I mean, once you figure out like fusion, 0:17:01.480 --> 0:17:04.600 then probably have a pretty good chance. Fusion is great. 0:17:04.840 --> 0:17:07.680 Fusion is great. Once you get into space to actually 0:17:07.920 --> 0:17:11.160 create lift with thrust, it would be interesting. I'm sure 0:17:11.160 --> 0:17:13.240 there's a way to do it. I'm just I guess 0:17:13.240 --> 0:17:14.800 you could probably even do it with steam if you 0:17:15.040 --> 0:17:17.760 really wanted to, like if you wanted to write a 0:17:17.840 --> 0:17:22.520 boiler into space plan Yeah, But fusion I think of 0:17:22.560 --> 0:17:25.680 as more of a way of releasing a controlled amount 0:17:25.680 --> 0:17:28.040 of energy over a long period of time, as opposed 0:17:28.040 --> 0:17:30.919 to that burst that you need in order to escape 0:17:30.960 --> 0:17:35.000 the bonds of Earth or whatever hypothetical plant. Yeah, maybe 0:17:35.000 --> 0:17:40.440 you could do one of those nuclear explosion reactions you do, 0:17:40.480 --> 0:17:43.440 the use nuclear bombs to propel yourself. You just yeah, 0:17:43.480 --> 0:17:46.280 it's like I've actually read about this, using like three 0:17:46.359 --> 0:17:49.560 or four nuclear explosions to propel an object into space. 0:17:50.200 --> 0:17:52.280 I mean, once you're real done with the planet, then 0:17:52.320 --> 0:17:55.960 why not. I've been stuck here for thousands of years. 0:17:55.960 --> 0:17:59.760 I'm sick of it for them, For them, nuclear real 0:18:00.040 --> 0:18:05.200 asian might be a tasty treat. So at any rate, 0:18:05.359 --> 0:18:07.720 getting back to some of the other things that affect 0:18:08.320 --> 0:18:11.919 rockets taking off, there's also air pressure, so this is 0:18:11.960 --> 0:18:14.600 interesting too. You know, you have to counteract air pressure 0:18:14.600 --> 0:18:16.920 in order to have gas escape from the rocket in 0:18:16.920 --> 0:18:20.000 the first place. Right, If the air pressure were too strong, 0:18:20.400 --> 0:18:23.359 it would be like a cork, so no gas would 0:18:23.359 --> 0:18:27.280 ever escape your rocket. So your rocket has to produce 0:18:27.440 --> 0:18:30.200 more internal pressure than there is air pressure here on Earth. 0:18:30.320 --> 0:18:33.120 Not such a big deal, right, If air pressure were 0:18:33.160 --> 0:18:36.000 that great where a rocket could not generate enough internal 0:18:36.040 --> 0:18:39.720 pressure to escape, we wouldn't be breathing right now. But 0:18:39.800 --> 0:18:41.760 it is a factor that you have to take into 0:18:41.800 --> 0:18:45.240 account when again you're a rocket scientist, it's not completely 0:18:45.280 --> 0:18:48.320 trivial where you can ignore it. Also, rockets have to 0:18:48.359 --> 0:18:51.720 obviously be strong enough to contain that internal pressure. If 0:18:51.760 --> 0:18:54.040 they didn't, they would not be rockets. They would be 0:18:54.080 --> 0:18:58.520 bombs because it would explode. Uh, that would be what 0:18:58.560 --> 0:19:01.160 you would call something that is unable to contain the 0:19:01.200 --> 0:19:04.680 pressure that generates inside of it. Um And until recently 0:19:04.720 --> 0:19:06.760 they were one use affairs. It's kind of like with 0:19:06.840 --> 0:19:10.040 your kitchen example, my car example. The idea that you 0:19:10.160 --> 0:19:13.159 use this thing one time. Other couple of exceptions that 0:19:13.520 --> 0:19:15.280 the one that Lauren will pick up in a second. 0:19:15.680 --> 0:19:18.879 But in general, you'd use it to launch something up 0:19:18.920 --> 0:19:21.720 into space. It would fall back to Earth, usually in 0:19:21.760 --> 0:19:25.440 an ocean. That's what where that's where we wanted to go. Also, 0:19:25.480 --> 0:19:27.760 the oceans cover more of the surface of the plant 0:19:27.760 --> 0:19:30.600 than than land mask does. And you might go out 0:19:30.640 --> 0:19:33.680 and retrieve it, but you probably weren't going to use 0:19:33.680 --> 0:19:35.359 it again, which meant that you had to build a 0:19:35.400 --> 0:19:37.640 whole new one the next time you wanted to put 0:19:37.680 --> 0:19:39.760 something on the space. Yeah, or you would have to 0:19:39.760 --> 0:19:43.960 put a whole lot of work into making that thing reusable. Yeah. 0:19:44.280 --> 0:19:47.760 For For example, for the Space Shuttle, NASA designed components 0:19:47.800 --> 0:19:51.639 that could be retooled and reused the there two solid 0:19:51.720 --> 0:19:54.200 rocket boosters were the parts that got the shuttle off 0:19:54.280 --> 0:19:56.600 the ground and end up some like twenty eight miles 0:19:56.680 --> 0:20:00.280 or KOs And at that point they'd separate and and 0:20:00.320 --> 0:20:04.119 those solid rocket boosters would parachute into the Atlantic. The 0:20:04.200 --> 0:20:06.200 Navy would go out and pick them up, and then 0:20:06.240 --> 0:20:08.440 they could be taken back into the into the lab 0:20:08.480 --> 0:20:11.040 and refurbished for future launches. But it was such an 0:20:11.040 --> 0:20:14.320 intense process because of the solid part of those solid 0:20:14.400 --> 0:20:17.640 rocket boosters that they used solid fuel instead of liquid, 0:20:17.960 --> 0:20:20.680 so huge parts of the rockets had to be completely 0:20:20.680 --> 0:20:23.639 replaced each time. But I mean that was the whole 0:20:23.920 --> 0:20:26.119 idea behind the space shell, right, was that they were 0:20:26.119 --> 0:20:29.240 trying to make as much of it reusable as possible. 0:20:29.320 --> 0:20:32.680 Like that was the whole concept behind that particular era 0:20:32.880 --> 0:20:35.760 of NASA's space exploration was we want, we want, We're 0:20:35.760 --> 0:20:38.520 limited the low Earth orbit, but we can keep using 0:20:38.560 --> 0:20:42.120 this equipment repeatedly. And it had some stages that couldn't 0:20:42.119 --> 0:20:45.400 be reused. Right. The external tank, which was the shuttle's 0:20:45.400 --> 0:20:48.200 main fuel tank, would burn up upon re entry after 0:20:48.440 --> 0:20:50.880 launching the shuttle the rest of the way into low 0:20:50.880 --> 0:20:52.800 Earth orbits. And and that's a good point to make 0:20:52.840 --> 0:20:57.000 because there actually if you want to use a reusable 0:20:57.119 --> 0:21:00.000 rocket to get you not just to the edge of space, 0:21:00.119 --> 0:21:03.840 spit up into orbit around the Earth and then back safely, 0:21:04.320 --> 0:21:06.639 there are a couple things you've got to take into consideration. 0:21:06.760 --> 0:21:09.240 One of them would be making it so that it 0:21:09.359 --> 0:21:12.400 survives re entry into the atmosphere from space. We've got 0:21:12.400 --> 0:21:14.920 it up in orbit. Uh, it's got to be able 0:21:14.960 --> 0:21:17.879 to get back into our gassy soup I talked so 0:21:17.920 --> 0:21:22.320 wonderfully about with that drag. Thing becomes pretty intense without 0:21:22.359 --> 0:21:24.800 burning and breaking apart. And then it's also got to 0:21:24.840 --> 0:21:28.560 survive contact with the surface of the Earth. And so furthermore, 0:21:28.600 --> 0:21:30.440 I mean, I don't know about any of you guys, 0:21:30.480 --> 0:21:33.600 but every time I dunk my expensive electronics and an ocean, 0:21:33.880 --> 0:21:37.959 they don't work anymore after. So so that's that's another thing, 0:21:38.000 --> 0:21:39.960 Like if you have an ocean splashed down, then you're 0:21:40.000 --> 0:21:43.000 trying to get this thing ready to fly into space. 0:21:43.080 --> 0:21:45.440 And that's why all all those rockets have that one 0:21:45.480 --> 0:21:47.680 sticker that goes from white to black. If it's had 0:21:47.720 --> 0:21:50.760 contact with an ocean um in case you didn't notice 0:21:50.800 --> 0:21:52.480 it as you were fishing it out of the Pacific 0:21:52.560 --> 0:21:56.840 or Atlantic. Yeah, so the reusable rocket idea is very 0:21:56.880 --> 0:21:59.600 attractive and that it can lower costs that you can 0:21:59.680 --> 0:22:03.160 keep you equipment instead of having to rebuild it every 0:22:03.200 --> 0:22:06.480