WEBVTT - Setting Sail for the Stars 0:00:00.160 --> 0:00:07.080 Brought to you by Toyota. Let's go places. Welcome to 0:00:07.280 --> 0:00:13.520 Forward Thinking. Hey there, and welcome to Forward Thinking, the 0:00:13.560 --> 0:00:17.000 podcast that looks at the future and says, I'm sailing away. 0:00:17.200 --> 0:00:20.480 I'm Jonathan Strickland, I'm Lauren Bocan, and I'm Joe McCormick. 0:00:20.960 --> 0:00:24.680 And guys, I thought today we could talk about solar sales. 0:00:24.720 --> 0:00:27.200 We've mentioned them a few times in past episodes, and 0:00:27.680 --> 0:00:30.040 I will probably talk about them in future episodes too. 0:00:30.080 --> 0:00:32.360 But the reason why I specifically wanted to bring it 0:00:32.440 --> 0:00:34.840 up is because, not too long ago, in the news 0:00:35.080 --> 0:00:40.000 we're recording this in June, there was a story about 0:00:40.040 --> 0:00:43.519 a crowd funded solar sale projects. So we're gonna talk 0:00:43.560 --> 0:00:46.159 about that a little bit later in the episode. But 0:00:46.200 --> 0:00:49.199 in order for that conversation to even make sense, we 0:00:49.280 --> 0:00:51.160 need to just kind of talk about what these things 0:00:51.200 --> 0:00:54.400 are in general and what their purpose is. Now we're 0:00:54.440 --> 0:00:58.400 solar sales, the vessels that Sailor Moon and the other 0:00:58.520 --> 0:01:01.920 sailor scouts sail I don't know, because Lauren had not 0:01:02.040 --> 0:01:06.320 gotten that far into the explanation of what Sailor Moon 0:01:06.560 --> 0:01:09.320 is all about for us. Can you help us out here, Lauren, 0:01:09.520 --> 0:01:12.520 um I believe they are not, although I'm sure the 0:01:12.600 --> 0:01:17.119 magical cats Luna and Artemis are very fine sailors. We 0:01:17.120 --> 0:01:21.959 we honestly were having Lauren explained to us what sailor 0:01:22.000 --> 0:01:26.080 Moon is all about earlier. So so, yeah, that's just 0:01:26.160 --> 0:01:29.679 a peak in the inner working, so forward thinking. But 0:01:29.760 --> 0:01:33.160 of course solar sales are not a component of a cartoon. 0:01:33.240 --> 0:01:37.480 They are a reality. Yeah. Yeah, it's a propulsion system 0:01:37.520 --> 0:01:42.640 that doesn't require fuel. Now, we just recently on this podcast, 0:01:42.680 --> 0:01:47.160 talked about a supposed propulsion system that doesn't require fuel 0:01:47.240 --> 0:01:50.160 in our podcast on the M drive and the microwave 0:01:50.200 --> 0:01:54.000 oven that makes rockets go, well, yes, supposedly, no, no, 0:01:54.160 --> 0:01:56.840 makes a vessel go without the need for rockets, and 0:01:57.120 --> 0:02:01.080 the appeal of the M drive as it is supposed 0:02:01.120 --> 0:02:03.760 to work. Now, we ended that podcast with a lot 0:02:03.800 --> 0:02:06.720 of hesitation about whether something like this could actually work. 0:02:06.800 --> 0:02:09.640 But if you take the M drive proponents at their word, 0:02:09.760 --> 0:02:12.920 what they're saying happens is they've got a method for 0:02:13.040 --> 0:02:17.120 making a spaceship go through space without a chemical reaction, 0:02:17.440 --> 0:02:20.120 shooting stuff out the back of it without any kind 0:02:20.120 --> 0:02:23.760 of propellent. Yeah yeah. And and the reason why that's important, 0:02:23.800 --> 0:02:27.480 obviously is that you can't carry an infinite amount of 0:02:27.560 --> 0:02:31.399 fuel on your spacecraft, right you. You are limited by 0:02:31.520 --> 0:02:35.880 the volume of whatever vessel you have, and the reality 0:02:35.960 --> 0:02:37.880 that fuel is a three dimensional thing that you have 0:02:37.919 --> 0:02:40.360 to lug around, right yeah, And that it adds weight 0:02:40.400 --> 0:02:42.960 to the spacecraft, which means the more weight you add, 0:02:43.000 --> 0:02:45.600 the more fuel you need in order to escape the 0:02:45.639 --> 0:02:48.679 gravitational poll of the Earth I mean. And then once 0:02:48.680 --> 0:02:51.600 you're out into space, then you need more fuel to 0:02:51.760 --> 0:02:54.040 get to where you're going to accelerate to whatever the 0:02:55.240 --> 0:02:58.280 top speed is. You can only accelerate so much with fuel. 0:02:58.760 --> 0:03:01.079 Of course, if you had some sort of system that 0:03:01.120 --> 0:03:07.200 could gather fuel while you are sailing through space, then 0:03:07.320 --> 0:03:10.320 that would help solve it. And there are ideas like 0:03:10.360 --> 0:03:13.919 that you can travel along through space picking up tiny 0:03:14.000 --> 0:03:17.120 particles and ions and and heaving those out the back 0:03:17.160 --> 0:03:19.520 of a spacecraft. There's not much mass in those, so 0:03:19.560 --> 0:03:22.440 you don't get a lot of acceleration, but slowly over 0:03:22.480 --> 0:03:25.000 time you can build up speed with the method like that. 0:03:25.160 --> 0:03:28.880 And another method similar is solar sales, and that it's 0:03:28.960 --> 0:03:34.040 again one something that has a steady but but low acceleration, 0:03:34.600 --> 0:03:38.480 so you're you're consistently accelerating at least until you get 0:03:38.520 --> 0:03:41.480 to really kind of the top speed of whatever mass 0:03:41.880 --> 0:03:46.000 you are you are using. Uh, but you are accelerating 0:03:46.040 --> 0:03:48.680 steadily up to that point. It's just that it's a 0:03:48.720 --> 0:03:51.560 low level of acceleration. And the reason why we call 0:03:51.560 --> 0:03:55.080 them solar sales is that they're very similar, at least 0:03:55.080 --> 0:03:58.160 in concept, to the sales that we use here on 0:03:58.280 --> 0:04:01.800 Earth to propel things like oats and ships, right, which 0:04:01.800 --> 0:04:04.680 are I suppose technically fueled by the sun because the 0:04:04.680 --> 0:04:08.760 Sun heats the Earth which makes the wind blow. That's true. Yeah, 0:04:08.800 --> 0:04:11.080 if we go far enough back, it is. It is 0:04:11.200 --> 0:04:14.200 kind of a solar powered means of propulsion. But surely 0:04:14.200 --> 0:04:17.920 you're not suggesting that there is wind in space. Well, 0:04:17.960 --> 0:04:22.680 it's similar into wind in space. We're specifically talking about 0:04:22.680 --> 0:04:25.680 photons in the case of solar sales. But before I 0:04:25.680 --> 0:04:27.520 get too far, I do want to make one distinction 0:04:27.600 --> 0:04:31.720 clear for any of our sailing friends out there. It's 0:04:32.000 --> 0:04:35.479 more a solar sales more like a an Earth sail 0:04:36.040 --> 0:04:39.520 if you were sailing directly downwind. Uh. This is an 0:04:39.520 --> 0:04:42.400 important distinction because sales can actually be used to sail 0:04:43.480 --> 0:04:46.480 sort of into the wind, which seems counterintuitive. But it's 0:04:46.520 --> 0:04:49.720 because the construction of sales is such that they act 0:04:49.800 --> 0:04:53.400 kind of like a airplane wing does, so you can 0:04:53.440 --> 0:04:57.359 actually yeah, yeah, Otherwise you could only go in the 0:04:57.400 --> 0:04:59.279 same direction that the wind is blowing, which would not 0:04:59.320 --> 0:05:02.880 be terribly that would be inconvenient. I've actually always wondered 0:05:02.880 --> 0:05:05.160 about that. I have no idea how that works. It's 0:05:05.279 --> 0:05:07.800 very much like a like an airplane wing. It's designed 0:05:07.839 --> 0:05:11.240 so that the airflow is different across one surface than 0:05:11.320 --> 0:05:15.040 the other, and it's it's similar to generating left except 0:05:15.040 --> 0:05:19.159 you're generating thrust essentially, So solar sales are more like 0:05:19.279 --> 0:05:21.760 if you're sailing directly down wind, you're catching the wind 0:05:21.880 --> 0:05:24.440 to push you forward. In this case, a solar sale 0:05:24.480 --> 0:05:28.120 is capturing or or is acting as kind of a 0:05:28.160 --> 0:05:32.880 surface for photons to bounce off of. And photons, as 0:05:32.880 --> 0:05:35.400 we have talked about many times on this show, are 0:05:35.480 --> 0:05:39.360 particles of light. Sure, A photon is a a quantum 0:05:39.520 --> 0:05:43.040 of light. It's the smallest indivisible unit of light energy 0:05:43.520 --> 0:05:48.560 that transfers the electromagnetic force throughout the universe. So yeah, 0:05:48.600 --> 0:05:51.080 the Sun is of course putting out lots of photons 0:05:51.120 --> 0:05:53.880 all the time, shining them out into the universe. That 0:05:54.080 --> 0:05:57.839 shining is of course electromagnetic radiation, and it turns out 0:05:57.920 --> 0:06:02.080 you can use that shine, meaning the sunshine, the electromagnetic 0:06:02.200 --> 0:06:05.320 radiation coming off of the Sun to push a sail 0:06:05.480 --> 0:06:07.640 in the same way the wind would push a sail 0:06:07.720 --> 0:06:12.240 on Earth. But that's kind of weird because the wind 0:06:12.360 --> 0:06:15.240 that pushes a sail on Earth is made up of 0:06:15.720 --> 0:06:20.200 particles of air. It's gas, it's massive particles, and it's 0:06:20.279 --> 0:06:22.600 very easy to see how that imparts a force, how 0:06:22.680 --> 0:06:27.320 that gives momentum to the craft that's attached to the sail, right, 0:06:27.360 --> 0:06:30.760 because yet again the air that we are breathing is 0:06:30.839 --> 0:06:35.120 not open empty space. It's soup. Right. But if you 0:06:35.160 --> 0:06:40.400 remember from like a high school physics class, what is momentum, 0:06:40.440 --> 0:06:43.640 There's that equation P equals m v, so that will 0:06:43.640 --> 0:06:47.600 tell you that momentum is mass times velocity. So you 0:06:47.720 --> 0:06:49.799 take the you know, the mass of the wind hitting 0:06:49.800 --> 0:06:52.240 the sail and how fast it's hitting the sail on 0:06:52.320 --> 0:06:56.320 that vector. That's important. And I was about I was 0:06:56.320 --> 0:06:58.360 about to throw in the direction, but you you covered 0:06:58.360 --> 0:07:01.800 it exactly. Velocity is is a is a vector, and 0:07:01.839 --> 0:07:05.559 that you need both a magnitude in a direction for 0:07:05.640 --> 0:07:09.560 that particular measurement. But yes, exactly. You take that mass, 0:07:09.600 --> 0:07:12.160 you take the velocity, you multiply them together, you get 0:07:12.160 --> 0:07:15.280 the momentum. This is sort of a way of describing 0:07:15.400 --> 0:07:21.360 the movement energy of UH an object in motion and 0:07:21.840 --> 0:07:24.960 with massive objects. That makes it pretty simple to understand. 0:07:25.040 --> 0:07:29.200 You know. You think, oh, if I'm running at a 0:07:29.320 --> 0:07:32.360 speed of eight miles per hour, I have a certain 0:07:32.360 --> 0:07:34.360 amount of momentum. It's going to take a certain amount 0:07:34.400 --> 0:07:38.000 of energy to stop me because of the the energy 0:07:38.040 --> 0:07:42.000 that I that that represents. If a semitruck is traveling 0:07:42.040 --> 0:07:44.480 at eight miles per hour, it's going to need more 0:07:44.680 --> 0:07:46.920 energy to stop it because it is a much more 0:07:47.040 --> 0:07:49.720 massive object, all right, And in the stopping of it, 0:07:49.720 --> 0:07:52.640 it's going to transfer some of that momentum to the 0:07:52.920 --> 0:07:55.320 object of stopping. Yeah. So if you if you have 0:07:55.400 --> 0:08:00.280 something that is has less uh potential force there, then 0:08:00.360 --> 0:08:02.280 you probably aren't going to stop this in my truck, 0:08:02.720 --> 0:08:06.680 but you will definitely alter the stopping whatever it was, 0:08:06.800 --> 0:08:10.920 like a wall or fence. Yeah. But photons, the makeup 0:08:11.120 --> 0:08:14.920 of the sunshine don't have any mass. They don't have 0:08:15.000 --> 0:08:19.320 a rest mass or variant mass, right, Yeah, so this 0:08:19.440 --> 0:08:21.400 makes it a little tricky because you would think, well, 0:08:21.520 --> 0:08:25.080 we just talked about how that that equation is mass 0:08:25.120 --> 0:08:28.640 times velocity, So how could a photon that has no 0:08:28.800 --> 0:08:33.439 mass transfer momentum, I mean, momentum depends on mass, right, Yeah, 0:08:33.559 --> 0:08:36.440 But one way I've seen of explaining this is to 0:08:36.480 --> 0:08:41.800 say that momentum isn't really fundamentally mass times velocity. That's 0:08:41.880 --> 0:08:45.840 just sort of the Newtonian level shortcut for describing how 0:08:45.880 --> 0:08:48.480 things work, and and it makes sense because for most 0:08:48.520 --> 0:08:50.240 of us that's i mean, that's the world we live in, 0:08:50.280 --> 0:08:53.080 I'm sure in the macro level, or at the macro level. 0:08:53.200 --> 0:08:58.680 Rather if we're going to use prepositions correctly, which we are, Uh, 0:08:58.720 --> 0:09:02.800 that's completely valid. But photons are are in that strange 0:09:02.840 --> 0:09:10.120 little little less than big. Yeah, we're talking quantum level 0:09:10.120 --> 0:09:12.040 on there. Yeah. So you could look at this in 0:09:12.200 --> 0:09:15.880 terms of quantum mechanics or in terms of relativity. But 0:09:16.240 --> 0:09:19.320 either way, what this works out too is that the 0:09:19.480 --> 0:09:23.320 energy of a photon sort of plays the role of 0:09:23.440 --> 0:09:25.920 mass that we would usually think about in this equation. 0:09:25.960 --> 0:09:29.720 And Einstein pointed this out right, there's the famous equation 0:09:29.920 --> 0:09:33.520 E equals mc squared. This tells you the relationship between 0:09:33.640 --> 0:09:38.080 energy and mass. So a small amount of mass is 0:09:38.120 --> 0:09:40.960 equivalent to an enormous amount of energy because you're multiplying 0:09:40.960 --> 0:09:44.120 at times the constant of the speed of light squared. Well, 0:09:44.120 --> 0:09:47.520 that also means that mass is equal to energy divided 0:09:47.600 --> 0:09:51.880 by c squared. You know, you just change around the 0:09:51.200 --> 0:09:56.760 the equation there. So that photon, that representation of a 0:09:56.880 --> 0:10:00.920 of an amount of energy of light is equivalent to 0:10:01.320 --> 0:10:03.600 a certain amount of mass. It's just a very small 0:10:03.679 --> 0:10:06.800 amount of mass. But that small amount of mass doesn't 0:10:06.960 --> 0:10:08.640 think you know, the fact that it's small doesn't really 0:10:08.679 --> 0:10:12.600 matter because of two big things. Really. One is that 0:10:12.640 --> 0:10:15.960 in space you don't have gravity to work against. So, uh, 0:10:16.160 --> 0:10:19.079 any amount of momentum transferred to the solar sale is 0:10:19.120 --> 0:10:22.920 going to have some effect the the solar sale is 0:10:22.920 --> 0:10:25.360 going to end. Whatever is attached to it is going 0:10:25.400 --> 0:10:28.160 to move in the opposite or or is going to 0:10:28.200 --> 0:10:32.160 move in the same direction as the impact. Secondly, it's 0:10:32.200 --> 0:10:34.560 not like it's a single photon that's saying the solar sale. 0:10:34.640 --> 0:10:36.840 There are lots of photons hitting the solar sale. They're 0:10:36.880 --> 0:10:39.960 doing so at the speed of light. Uh, So you 0:10:40.000 --> 0:10:42.600 are getting a transfer of momentum in that way. Light 0:10:42.720 --> 0:10:47.120 itself can have momentum, as can other types of electromagnetic radiation, 0:10:47.200 --> 0:10:50.640 so that's kind of exciting. So each individual photon imparts 0:10:50.679 --> 0:10:53.880 only a very slight amount of momentum, but there's enough 0:10:54.000 --> 0:10:56.800 of them that you can build up a traveling force 0:10:56.840 --> 0:11:00.640 over time, right. And the amount of moment to possessed 0:11:00.640 --> 0:11:05.160 by any individual photon is dependent upon that photons wavelength 0:11:05.240 --> 0:11:09.000 and frequency. So if you were to take a photons 0:11:09.040 --> 0:11:13.880 frequency and its wavelength and multiply them together, the product 0:11:13.880 --> 0:11:17.040 would be the speed of light, all right. So in 0:11:17.080 --> 0:11:20.400 other words, if you have a longer wavelength of light, 0:11:20.720 --> 0:11:22.880 it's going to have a lower frequency. Though those two 0:11:22.920 --> 0:11:25.360 have to change, right, because the end product has to 0:11:25.360 --> 0:11:27.600 be the speed of light with a photon. If you 0:11:27.640 --> 0:11:30.640 know one of these variables, you know the other one, right. 0:11:31.040 --> 0:11:35.080 So higher frequencies have shorter wavelengths, and they also have 0:11:35.280 --> 0:11:39.200 higher energy levels. So a high frequency, short wavelength photon 0:11:39.600 --> 0:11:42.560 has more energy than one that has a lower frequency 0:11:42.600 --> 0:11:46.880 but longer wavelength. Uh, that's important as well. And Uh, 0:11:46.920 --> 0:11:51.160 there's an astrophysicist that actually, Joe you had had clued 0:11:51.200 --> 0:11:53.520 me in on that. I had read some of his 0:11:53.600 --> 0:11:57.000 work before, but didn't know him by name and his 0:11:57.120 --> 0:12:00.520 explanations of this sort of stuff really made it a 0:12:00.520 --> 0:12:03.760 lot easier to understand. Yeah, his name is Ethan Siegel. 0:12:03.840 --> 0:12:06.240 He's one of my favorite science bloggers on the internet. 0:12:06.280 --> 0:12:09.240 He's on Twitter as at starts with the Bang. He's 0:12:09.280 --> 0:12:12.240 really worth reading. And he also, for me, has made 0:12:12.240 --> 0:12:17.000 a lot of sort of astrophysics concepts much easier to grasp. Yeah, 0:12:17.160 --> 0:12:20.040 and he's also he's also kind of an eccentric guy, 0:12:20.320 --> 0:12:24.640 and I dig that. It's pretty awes Yes, he does. Yeah, 0:12:24.920 --> 0:12:26.800 like his Twitter handle, he's got horns coming out of 0:12:26.800 --> 0:12:29.520 his head and stuff. It's pretty pretty cool. Cool. Yeah, 0:12:29.679 --> 0:12:33.840 So now we've we've got up the the physics behind 0:12:33.960 --> 0:12:38.800 why solar sales could work as a means of propelling 0:12:38.920 --> 0:12:44.520 a spacecraft without using any actual fuel. Uh. Now, to 0:12:44.559 --> 0:12:47.959 actually take advantage of it, you have to build your 0:12:48.040 --> 0:12:52.400 spacecraft in a very strategic way. You want to minimize 0:12:52.400 --> 0:12:56.760 the amount of mass you're using so that the propulsion 0:12:56.880 --> 0:13:01.440 from the solar energy is max smized, because the more 0:13:01.480 --> 0:13:03.640 massive it is, the more solar energy you're going to 0:13:03.720 --> 0:13:05.400 need to you know, it's going to it's going to 0:13:05.440 --> 0:13:09.240 accelerate slower and slower, or as the mass increases, the 0:13:09.559 --> 0:13:12.360 rate of acceleration is lower, so it takes longer to 0:13:12.400 --> 0:13:16.000 accelerate to those incredible speeds. Alright, same principle is if 0:13:16.000 --> 0:13:18.599 you have a heavier car, it takes more gas to 0:13:19.320 --> 0:13:22.000 move it, right yeah, yeah, very similar to that. But 0:13:22.040 --> 0:13:26.640 you also want the largest possible surface on which the 0:13:26.679 --> 0:13:29.360 sun can push right yeah. Yeah. It doesn't do you 0:13:29.440 --> 0:13:31.720 much good if your solar sale is you know, a 0:13:31.720 --> 0:13:34.320 couple of square inches, then it's not going to capture 0:13:34.840 --> 0:13:37.440 enough photons for that to really be worthwhile. So you 0:13:37.480 --> 0:13:40.040 want a lot of surface area, uh, and not a 0:13:40.040 --> 0:13:42.800 lot of mass. So that also means that whatever material 0:13:42.920 --> 0:13:45.719 you're using, you want it to be super thin. Uh. 0:13:45.840 --> 0:13:48.080 Tends to be reflective, so the photons hit it, they 0:13:48.120 --> 0:13:51.240 bounce off, and the momentum is transferred to the solar sale, 0:13:51.440 --> 0:13:55.880 which in turn transfers that momentum to the spacecraft itself. Uh. Now, 0:13:55.920 --> 0:13:59.839 this acceleration, like we said, is small, but and it 0:14:00.200 --> 0:14:04.200 is continuous. So the longer the spacecraft is capturing the 0:14:04.240 --> 0:14:09.880 solar energy, the faster it is moving. It's accelerating slowly 0:14:09.920 --> 0:14:12.800 over time, but it keeps going until you've reached the 0:14:12.840 --> 0:14:17.840 maximum speed that spacecraft can go according to its uh mass, 0:14:18.040 --> 0:14:20.920 or you are no longer able to capture a significant 0:14:20.960 --> 0:14:24.160 amount of photons to continue accelerating. But either way, at 0:14:24.160 --> 0:14:26.680 that point, you're traveling at an incredible, incredible speed and 0:14:26.680 --> 0:14:29.880 you're not going to slow down unless you encounter something 0:14:29.920 --> 0:14:32.640 that makes you slow down, like an asteroid, yeah, or 0:14:32.640 --> 0:14:34.960 a planet or a moon or something that has a 0:14:34.960 --> 0:14:39.600 gravitational effect on your spacecraft. Right, or you know those 0:14:40.160 --> 0:14:44.280 jerk aliens. I hate the jerk aliens, always clinging onto 0:14:44.280 --> 0:14:50.120 stuff much before rotisserie. Oh nice, Okay, so moving on. 0:14:50.200 --> 0:14:54.360 Typically this super thin solar sale is only a few 0:14:54.360 --> 0:14:58.480 microns thick. So to get an idea of how thin 0:14:58.560 --> 0:15:01.880 we're talking about, I you get a plastic bag from 0:15:01.960 --> 0:15:05.400 grocery store, you know, your typical thin plastic bag. Those 0:15:05.440 --> 0:15:08.760 tend to be twice as thick or more than twice 0:15:08.840 --> 0:15:11.720 as thick as the solar sale material. So this is 0:15:12.600 --> 0:15:16.800 really thin, delicate stuff. Yeah. That material is typically a 0:15:16.880 --> 0:15:21.400 polymer film that's capable of withstanding the high temperature fluctuations 0:15:21.440 --> 0:15:23.840 of space because it can be pretty chilly and it 0:15:23.880 --> 0:15:26.280 can also be pretty warm, depending on how much radiation 0:15:26.320 --> 0:15:29.200 is hitting you at the time. Some researchers have also 0:15:29.320 --> 0:15:33.600 investigated using carbon fiber woven to be you know, hundreds 0:15:33.640 --> 0:15:36.960 of times thicker than these films would be, but just 0:15:37.040 --> 0:15:41.560 as a light due to their structure, their holy holy structure. Ye, 0:15:41.920 --> 0:15:44.200 holy as in lots of holes in it. Yes, yes, 0:15:44.640 --> 0:15:47.640 you really can't say holy twice without saying it thrice, 0:15:48.160 --> 0:15:51.440 holy holy holy, Right, let's hear it again, holy holy 0:15:51.480 --> 0:15:58.600 holy structure. Um, that's my high Church of technology talking. 0:15:58.800 --> 0:16:01.920 That's fair, thank you, thank you. So if you're wondering 0:16:01.960 --> 0:16:06.160 what kind of fantastic speeds were actually talking about, well, 0:16:06.320 --> 0:16:10.640 Planetary Society co founder Lou Friedman once told the UK's 0:16:10.720 --> 0:16:13.240 Royal Society of Chemistry, and by once, I mean back 0:16:13.240 --> 0:16:17.040 in two thousand nine that the contemporary technology should allow 0:16:17.080 --> 0:16:22.120 acceleration rates of about point zero zero zero five meters 0:16:22.200 --> 0:16:25.760 per second. Well, all right, so what's the miles per hour? 0:16:25.960 --> 0:16:28.600 That's point zero one miles per hour. This is the 0:16:28.600 --> 0:16:32.840 acceleration rate. Yes, yes, um, I mean, of course, given 0:16:32.880 --> 0:16:36.040 a probable size of sail and weight of vehicle that 0:16:36.160 --> 0:16:38.680 you would expect to be launching like the kind of 0:16:38.680 --> 0:16:40.480 things that they were thinking about in two thousand nine, 0:16:40.680 --> 0:16:43.240 which we will get into a little bit later here, 0:16:43.360 --> 0:16:46.760 um to to get that up to a sort of 0:16:46.840 --> 0:16:49.760 range that's a little bit more understandable. Over the course 0:16:49.760 --> 0:16:52.640 of the of a day, that's about a hundred and 0:16:52.680 --> 0:16:55.680 sixty kilometers per hour a k A about a hundred 0:16:55.680 --> 0:16:59.360 miles per hour, and that means that in a year 0:16:59.400 --> 0:17:02.120 it could hit thing like fifty eight thousand kilometers per 0:17:02.120 --> 0:17:05.280 hour or thirty six thousand miles per hour, which is 0:17:05.600 --> 0:17:10.560 something like three times the speed of our current interplanetary missions. 0:17:10.560 --> 0:17:14.200 That's that's now, that's incredible because again, just through the 0:17:14.200 --> 0:17:17.280 fact that it is continuously accelerating, it's able to hit 0:17:17.320 --> 0:17:19.960 these speeds. And sure it takes a long time to 0:17:20.080 --> 0:17:22.920 hit those amazing speeds, but it can and it doesn't 0:17:22.960 --> 0:17:26.560 require the use of fuel. That's why it's so attractive. Now, 0:17:27.720 --> 0:17:30.199 what would you actually be using these solar sales for, 0:17:30.240 --> 0:17:34.240 I mean, what would it be propelling? Obviously, uh, we're 0:17:34.280 --> 0:17:37.959 not necessarily talking about manned missions here, where we'd have 0:17:38.040 --> 0:17:43.240 people aboard a uh some form of transport and using 0:17:43.280 --> 0:17:46.360 solar sales to move. That's a possibility, but it's not 0:17:46.400 --> 0:17:49.240 necessarily what they'd be used for. Well, they have very 0:17:49.240 --> 0:17:52.520 few moving parts because you really just need to be 0:17:52.600 --> 0:17:56.560 able to deploy the solar sale right, unfurl the sail, 0:17:57.160 --> 0:17:59.560 and and then you end up there. There needs to 0:17:59.560 --> 0:18:04.080 be some means of controlling the the attitude, the the 0:18:04.080 --> 0:18:07.280 the position. Yeah, the position of the spacecraft in relation 0:18:07.359 --> 0:18:11.200 to whatever source of photons you're talking about. You need 0:18:11.200 --> 0:18:13.560 that as well. But apart from that, you're you're pretty 0:18:13.640 --> 0:18:17.080 much set. So they're great candidates for reuse. So instead 0:18:17.119 --> 0:18:19.320 of having to build a spacecraft for every single mission, 0:18:19.480 --> 0:18:21.760 you could have a solar sale craft that could potentially 0:18:21.800 --> 0:18:24.840 be used multiple times before ever needing to be replaced. 0:18:25.200 --> 0:18:28.840 So they'd make really great delivery or cargo vehicles in 0:18:28.840 --> 0:18:32.600 this way, I've seen one of the big ones. One 0:18:32.600 --> 0:18:34.720 of the big use cases that has been put forward 0:18:34.840 --> 0:18:38.359 is it could be used to deliver cargo and supplies 0:18:38.400 --> 0:18:41.560 to Mars. Now, you wouldn't have a solar sales spacecraft 0:18:41.680 --> 0:18:46.280 land on Mars. That would not be good for anybody there. 0:18:46.720 --> 0:18:48.960 But what you could do is have it fly by 0:18:49.080 --> 0:18:54.879 Mars and do essentially a controlled drop of cargo. Or 0:18:54.920 --> 0:18:58.920 it could rendezvous with other spacecraft like a space station 0:18:59.000 --> 0:19:01.520 that's in orbit around on Mars. You could have a 0:19:01.560 --> 0:19:05.119 rendezvous where cargo gets transferred and then the solar sale 0:19:05.600 --> 0:19:08.240 is redirected and sent back to Earth. It can be 0:19:08.359 --> 0:19:14.119 kind of a taxi vehicle, another another interplanetary uber. It 0:19:14.119 --> 0:19:17.880 could be. Yeah, I wouldn't be surprised if we see 0:19:17.880 --> 0:19:19.520 an app for that in the next five years. But 0:19:19.840 --> 0:19:22.639 the next application would be possibly to create an early 0:19:22.680 --> 0:19:26.119 warning system for space weather. Uh. This would be really 0:19:26.200 --> 0:19:30.760 useful solar weather happens. I mean you probably are at 0:19:30.800 --> 0:19:34.520 least familiar with solar flares. They have the potential to 0:19:34.760 --> 0:19:37.600 disrupt electronics here on Earth. If it's a large enough 0:19:37.600 --> 0:19:42.199 solar flare, it can cause some surges in things like 0:19:42.280 --> 0:19:45.239 power grids, and in fact, it can even cause an 0:19:45.359 --> 0:19:48.400 entire blackout of a region if it's powerful enough. There's 0:19:48.400 --> 0:19:51.879 also coronal mass ejections, which sometimes but not always a 0:19:51.960 --> 0:19:56.000 company solar flares that can cause some problems, uh, and 0:19:56.040 --> 0:19:59.160 we're not always aware of them until it's pretty late 0:19:59.200 --> 0:20:01.280 in the game. So if we were able to put 0:20:01.320 --> 0:20:05.960 spacecraft into different orbits, then we can usually uh achieve 0:20:06.040 --> 0:20:10.200 on our own. Then with our other satellites and other probes, 0:20:10.560 --> 0:20:13.840 then we could have uh more of a a complete 0:20:13.920 --> 0:20:16.040 look at what's going on with the Sun at any 0:20:16.080 --> 0:20:20.000 given time, and then if we spot warning signs, we 0:20:20.080 --> 0:20:22.680 might be able to prepare ourselves in the event of 0:20:22.840 --> 0:20:26.840 a solar flare coronal mass ejection that could potentially cause 0:20:27.320 --> 0:20:29.840 havoc here on Earth. It might mean being able to 0:20:29.880 --> 0:20:34.720 balance loads or reduce loads on our electrical grids to 0:20:35.320 --> 0:20:39.400 reduce the potential damage that could happen. It's really important, 0:20:39.680 --> 0:20:41.320 and it's something that a lot of people have been 0:20:41.680 --> 0:20:44.439 pushing for for a while, saying, you know, it's just 0:20:44.480 --> 0:20:47.359 a matter of time before there's a big solar flare 0:20:47.440 --> 0:20:52.760 up that could at least temporarily cause real problems for 0:20:52.880 --> 0:20:57.399 us here on Earth or yeah, yeah, I mean the 0:20:57.560 --> 0:21:01.119 and these weather patterns happen in cycles. Now, just because 0:21:01.119 --> 0:21:03.480 they happened in cycles doesn't mean that every eleven years 0:21:03.520 --> 0:21:05.720 we're going to get a massive solar flare that's gonna 0:21:05.760 --> 0:21:09.679 wipe out you know, Detroit or something. It's that's not 0:21:09.760 --> 0:21:12.160 what it means. But it does mean that they there 0:21:12.200 --> 0:21:15.399 are periods of increased activity and then there are periods 0:21:15.400 --> 0:21:18.800 of a lull of activity. But this sort of spacecraft, 0:21:18.880 --> 0:21:22.760 a solar sales spacecraft that could go into these eccentric 0:21:22.840 --> 0:21:25.400 orbits that normally we wouldn't be able to achieve, could 0:21:25.480 --> 0:21:28.800 at least give us a heads up when that sort 0:21:28.800 --> 0:21:31.240 of thing might happen. You know, what could be even 0:21:31.320 --> 0:21:33.959 better is if we made one that was really big, 0:21:34.119 --> 0:21:37.840 just big enough to completely block the Sun from the Earth, 0:21:38.119 --> 0:21:40.800 and then we'd never have to worry about So you're 0:21:40.800 --> 0:21:44.560 taking the Mr. Burns approach. I see, I always liked 0:21:44.560 --> 0:21:49.200 something about him. Excellent. So it could also be used 0:21:49.200 --> 0:21:55.080 to propel spacecraft through interstellar space, not necessarily carrying humans, 0:21:55.080 --> 0:21:57.159 but maybe who knows, by the time we get to 0:21:57.200 --> 0:22:00.320 the point where we were seriously talking about in interstellar travel, 0:22:00.920 --> 0:22:04.480 it might be one of the more approved of ways 0:22:04.520 --> 0:22:08.080 of doing that. UM. But what you would typically do 0:22:08.240 --> 0:22:11.000 would you would have your spacecraft do a run near 0:22:11.040 --> 0:22:13.280 the Sun so it could get a good boost of 0:22:13.400 --> 0:22:18.879 energy and then uh accelerate as it moves outward to 0:22:19.200 --> 0:22:22.720 escape the solar system. Uh. Eventually you would get to 0:22:22.720 --> 0:22:25.119 a point where you would have fewer photons hit the 0:22:25.160 --> 0:22:28.480 solar sale, so you wouldn't really receive the acceleration that 0:22:28.560 --> 0:22:31.359 you had when you first passed by the Sun. But 0:22:31.400 --> 0:22:34.119 by that point you're already traveling at this insane speed, 0:22:34.480 --> 0:22:39.080 so it would be probably one of the more viable 0:22:39.160 --> 0:22:44.520 means of propelling a spacecraft outside the Solar System. Uh, 0:22:44.720 --> 0:22:47.800 in a you know, reasonable time frame. By reasonable, I'm 0:22:47.840 --> 0:22:51.280 still talking a long long time, you know, not necessarily 0:22:51.680 --> 0:22:53.800 something like oh, within within a year and a half 0:22:53.840 --> 0:22:55.840 will be on the Solar System. That yeah, but but 0:22:55.960 --> 0:22:59.280 more reasonable than the generations upon generations that it would 0:22:59.320 --> 0:23:03.119 currently take. You get out right doing like little slingshots 0:23:03.119 --> 0:23:07.560 around various planets and stuff. Um So, also it might 0:23:07.560 --> 0:23:10.679 be used to help protect us against collisions from space rocks, 0:23:11.359 --> 0:23:15.399 like like giant asteroids. I've actually read about this method. Yeah. 0:23:15.440 --> 0:23:19.600 So the idea is, if you have an asteroid on 0:23:19.640 --> 0:23:23.919 a collision course with Earth, you don't necessarily have to 0:23:24.119 --> 0:23:27.199 destroy the asteroid to protect the Earth. You just have 0:23:27.320 --> 0:23:30.280 to divert its path. Yeah. In fact, destroying the asteroid 0:23:30.400 --> 0:23:33.960