WEBVTT - Planes in Spaaaace 0:00:04.120 --> 0:00:07.160 Get in touch with technology with tech Stuff from how 0:00:07.200 --> 0:00:13.680 stuff Works dot com. Hey there, and welcome to tech Stuff. 0:00:13.720 --> 0:00:16.360 I'm your host, Jonathan Strickland. I'm an executive producer with 0:00:16.400 --> 0:00:19.520 How Stuff Works and I love all things tech and 0:00:19.840 --> 0:00:22.919 listener Ivan wrote into me and asked if I might 0:00:22.960 --> 0:00:28.880 record an episode about space planes. So today and tomorrow 0:00:28.880 --> 0:00:31.040 we're going to learn about space planes, because it turns 0:00:31.040 --> 0:00:34.159 out it's a big enough topic to warrant two episodes. 0:00:34.200 --> 0:00:37.080 We're gonna learn more or less how they work, why 0:00:37.120 --> 0:00:39.839 anyone was interested in building them, and some of the 0:00:39.920 --> 0:00:43.400 past and current projects that fall into that category. So 0:00:43.440 --> 0:00:47.920 to begin with, what the heck is a space plane? Well, 0:00:48.400 --> 0:00:51.960 like most stuff that has to do with space exploration, 0:00:52.600 --> 0:00:57.480 it's complicated. The general concept, if you're going super super 0:00:58.160 --> 0:01:01.480 high level, is that a space plane is a vehicle 0:01:01.760 --> 0:01:05.520 that can go into space, not necessarily into orbit, but 0:01:05.600 --> 0:01:08.920 at least into space and return to Earth, and it 0:01:08.959 --> 0:01:12.840 can fly under its own power. That's in contrast with 0:01:12.880 --> 0:01:16.200 other space vehicles like the Apollo or the soy US. 0:01:16.720 --> 0:01:20.319 Those have the tried and true methodology of ballistic re entry, 0:01:20.600 --> 0:01:23.679 also known as plummeting towards Earth under the force of 0:01:23.680 --> 0:01:26.360 gravity and then deploying a parachute to slow you down, 0:01:26.720 --> 0:01:28.560 and in the case of the soy Us, also having 0:01:28.600 --> 0:01:31.839 a quick blast of a retro rocket before you touch down, 0:01:31.880 --> 0:01:35.639 either in the ocean or on terra firma. A space 0:01:35.640 --> 0:01:38.920 plane would re enter Earth's atmosphere and then use the 0:01:39.000 --> 0:01:42.840 principles of powered flight or powered gliding to land at 0:01:42.880 --> 0:01:46.160 a designated landing strip, so they could actually not just 0:01:46.200 --> 0:01:49.400 control their descent, but steer and and go to a 0:01:49.400 --> 0:01:54.200 specific location for landing. This is actually way more complicated 0:01:54.200 --> 0:01:57.720 that I'm letting on at this stage, because you have 0:01:57.760 --> 0:02:00.760 to remember the principles of flight in space are very 0:02:00.840 --> 0:02:04.640 different than the principles of light. Here in the atmosphere 0:02:04.680 --> 0:02:09.280 of Earth. You have a fluid dynamics that work when 0:02:09.280 --> 0:02:11.880 you're flying through an atmosphere, and then you have the 0:02:11.960 --> 0:02:15.000 near vacuum of space when you're out in space. So, 0:02:15.200 --> 0:02:18.440 despite what science fiction films like Star Wars would have 0:02:18.520 --> 0:02:22.440 us believe, you wouldn't bank in outer space because there'd 0:02:22.440 --> 0:02:25.200 be no atmosphere for you to bank off of. In 0:02:25.240 --> 0:02:28.560 addition to these basic concepts I've just mentioned, we tend 0:02:28.639 --> 0:02:32.280 to tie to other things to the idea of space planes. 0:02:32.320 --> 0:02:35.120 One is that they should be reusable, meaning that you 0:02:35.160 --> 0:02:37.880 would refurbish a space plane after it's gone on a mission, 0:02:38.080 --> 0:02:40.000 and then you could use that exact same vehicle and 0:02:40.040 --> 0:02:42.919 a future mission, and that cuts down costs because you 0:02:42.919 --> 0:02:45.080 don't have to build a whole new one. The second 0:02:45.160 --> 0:02:47.919 big thing is that they should be easy and by 0:02:47.919 --> 0:02:51.080 that I mean cheaper to launch into space compared to 0:02:51.240 --> 0:02:55.120 other spacecraft. That's ideal. If you can figure out a 0:02:55.120 --> 0:02:57.880 way to make it easier to launch these types of 0:02:57.880 --> 0:03:01.840 spacecraft into space, you again bring down the cost of 0:03:01.880 --> 0:03:06.519 getting stuff into space. Under these general guidelines, you could 0:03:06.600 --> 0:03:09.799 say the space Shuttle qualifies as a space plane that 0:03:10.080 --> 0:03:12.960 totally is a type of space plane. It was reusable, 0:03:13.240 --> 0:03:15.639 it could return to Earth and powered glide so it 0:03:15.680 --> 0:03:18.639 can navigate to a specific landing strip. But the history 0:03:18.680 --> 0:03:24.720 of space planes dates way earlier than the Space Shuttle program. 0:03:24.720 --> 0:03:30.320 Perhaps the earliest design for a space plane would be 0:03:30.360 --> 0:03:34.560 the Silver Focal or silver Bird design. This was a 0:03:34.600 --> 0:03:38.360 proposal that dated in to the nineteen forties and it 0:03:38.400 --> 0:03:41.600 was in Germany during World War Two. The design was 0:03:41.680 --> 0:03:45.440 essentially a liquid fueled rocket that had some wings attached 0:03:45.440 --> 0:03:47.960 to it that was meant for a German pilot to 0:03:48.000 --> 0:03:51.800 fly up high into the atmosphere, essentially entering into what 0:03:51.840 --> 0:03:54.600 we would consider to be space, but not orbit. It 0:03:54.600 --> 0:03:57.960 would be a suborbital flight then to cross the Atlantic 0:03:58.000 --> 0:04:03.280 Ocean and descend in a a powered glide to attack 0:04:03.400 --> 0:04:07.320 a target in America like New York City. Now, while 0:04:07.320 --> 0:04:10.000 the Germans built some mock ups of this design, including 0:04:10.000 --> 0:04:12.800 one to use in wind tunnels, to make sure that 0:04:12.880 --> 0:04:17.520 the actual physical design of the body made sense, ultimately 0:04:17.560 --> 0:04:21.359 engineers concluded that it was too complicated to advanced to 0:04:21.440 --> 0:04:25.200 make practical. They just weren't quite there technologically to make 0:04:25.240 --> 0:04:31.479 it a practicality. But we'll revisit this concept shortly. In 0:04:31.520 --> 0:04:35.680 the nineteen fifties, a British engineer named Terrence non Wiler 0:04:35.960 --> 0:04:39.479 proposed an interesting concept called wave riding that would find 0:04:39.520 --> 0:04:43.200 its way into various space plane proposals. That started with 0:04:43.240 --> 0:04:46.160 a wing design called the carrot wing, which is a 0:04:46.200 --> 0:04:49.400 wing that has a type of concave pyramids shape to it. 0:04:49.720 --> 0:04:52.600 Non Wiler worked out a physical design that would allow 0:04:52.600 --> 0:04:56.919 an aircraft traveling at supersonic speeds to leverage the shock 0:04:56.960 --> 0:04:59.560 waves it was actually generating and use that as a 0:04:59.560 --> 0:05:04.520 lifting surface, which to me is incredible. That actually everything 0:05:04.560 --> 0:05:08.320 that has to do with supersonic and hypersonic flight physics 0:05:08.320 --> 0:05:12.480 to me is amazing. So what does that actually mean? 0:05:12.640 --> 0:05:15.960 Was a shock wave? Why do those things happen? Well, 0:05:16.040 --> 0:05:19.680 shock wave is a phenomenon that happens with really any 0:05:19.720 --> 0:05:22.960 type of wave, but we're specifically talking about sound waves here. 0:05:23.440 --> 0:05:26.760 When in a flow moves higher than the speed of 0:05:26.839 --> 0:05:29.920 sound in a given medium, and by flow I typically 0:05:29.960 --> 0:05:32.800 mean an object like an aircraft, but it could be 0:05:32.839 --> 0:05:35.479 other things. In fact, it could even be um the 0:05:35.480 --> 0:05:38.520 air itself moving faster than the speed of sound. So 0:05:38.560 --> 0:05:41.719 a cracking whip generates a small shock wave, a small 0:05:41.760 --> 0:05:44.479 little sonic boom type thing at the tip of the 0:05:44.480 --> 0:05:47.120 whip because it moves faster than the speed of sound 0:05:47.480 --> 0:05:49.520 when you crack it. So when you hear someone crack 0:05:49.520 --> 0:05:52.120 a whip, that means the very tip of that whip 0:05:52.240 --> 0:05:55.520 when it made that snap, was traveling faster than the 0:05:55.560 --> 0:05:58.600 speed of sound was. So let's get an understanding what's 0:05:58.600 --> 0:06:01.720 going on from a physics point of view. First, when 0:06:01.760 --> 0:06:05.800 something makes a sound, it's a physical phenomenon, right, It's 0:06:05.880 --> 0:06:12.000 it's the changing of pressure of uh air. Essentially air molecules. 0:06:12.320 --> 0:06:16.320 It's pushing them together or creating gaps and thus creating 0:06:16.360 --> 0:06:20.160 kind of a vacuum between them, and this propagates outward 0:06:20.240 --> 0:06:22.799 from the source. So we can visualize the sound wave 0:06:23.480 --> 0:06:28.239 as a sphere that's moving outward from something that's making 0:06:28.240 --> 0:06:30.880 the noise. So you've got a central object. Let's say 0:06:30.880 --> 0:06:34.279 it's a boom box or I guess if you guys 0:06:34.279 --> 0:06:37.320 don't know what a boom boxes, it's a it's a stereo, 0:06:37.640 --> 0:06:40.640 it's a radio, it's a it's a it's a smartphone 0:06:40.680 --> 0:06:45.520 playing Bruno Mars, it's playing music really loud, and the 0:06:45.720 --> 0:06:51.039 sound will travel out from a sphere from this central point. Technically, 0:06:51.160 --> 0:06:54.200 it travels out in all three dimensions, although obviously if 0:06:54.200 --> 0:06:56.679 you're playing something near the ground, it's gonna be bouncing 0:06:56.680 --> 0:06:59.640 off the ground at some point. But the sphere size 0:07:00.080 --> 0:07:03.080 increases at the rate of the speed of sound, right, 0:07:03.080 --> 0:07:06.400 because sound is traveling outward at the speed of sound, 0:07:07.360 --> 0:07:11.760 and gradually the that sound wave gets weaker and weaker 0:07:11.840 --> 0:07:15.360 as it propagates further and further out from the objects. 0:07:15.360 --> 0:07:17.520 So the further out you are from the object making sound, 0:07:17.520 --> 0:07:19.840 the quieter it's going to be to you. As the 0:07:19.880 --> 0:07:22.960 object continues to make sound, it's making more and more 0:07:23.000 --> 0:07:26.800 sound waves, so they're they're moving outward in this series 0:07:27.000 --> 0:07:31.520 of spheres that are growing out from the center of 0:07:31.600 --> 0:07:36.400 this sound storm. So we typically will illustrate this in 0:07:36.440 --> 0:07:39.600 a two dimensional format. It's much easier to understand that way. 0:07:39.640 --> 0:07:42.400 So you would just put a central point that would 0:07:42.400 --> 0:07:45.320 represent whatever the object is it's making sound, a stationary 0:07:45.360 --> 0:07:48.280 sound source, and you would surround that with a series 0:07:48.360 --> 0:07:54.240 of concentric circles and uh that suggests a sound wave 0:07:54.320 --> 0:07:57.240 that's traveling outward from that source, and it's a series 0:07:57.280 --> 0:08:01.280 of sound waves, actually, each concentric circle being another sound 0:08:01.280 --> 0:08:06.280 wave in this progression. So the further out you are 0:08:06.360 --> 0:08:09.280 from the object, the closer you are to the largest 0:08:09.320 --> 0:08:14.720 part of that of those circles. At this stage where 0:08:14.760 --> 0:08:19.400 you have an object making noise and it's stationary, all 0:08:19.440 --> 0:08:21.560 of the sounds are moving outward from the source and 0:08:21.600 --> 0:08:25.560 an equal rate of speed hitting things that are equidistant 0:08:25.640 --> 0:08:28.720 from the object at the same time. So if you 0:08:28.840 --> 0:08:31.200 were standing five ft to the right of the object, 0:08:31.240 --> 0:08:33.440 I'm standing five feet to the left of the object. 0:08:33.480 --> 0:08:36.880 The object is perfectly still. We're both gonna get hit 0:08:36.960 --> 0:08:40.439 by those sound waves at the same time we are equidistant. 0:08:41.000 --> 0:08:45.640 Sound is traveling at a uh standard speed and which 0:08:45.679 --> 0:08:48.680 is dependent upon the pressure and temperature and some other 0:08:48.720 --> 0:08:51.319 stuff in the air, but it's going to be traveling 0:08:51.320 --> 0:08:54.000 at that same speed through that medium. We're gonna hear 0:08:54.040 --> 0:08:55.880 at the same time. If I'm standing ten ft away 0:08:55.880 --> 0:08:58.240 and you're standing five feet away, it's gonna take longer 0:08:58.240 --> 0:09:00.959 for those sound waves to hit me then hit you. 0:09:01.280 --> 0:09:03.360 Not a whole lot longer, because the speed of sound 0:09:03.400 --> 0:09:06.120 is pretty fast, but technically it'll take a little longer 0:09:06.200 --> 0:09:08.880 to hit me than it does to hit you. If 0:09:08.880 --> 0:09:12.680 the object isn't stationary, then the picture changes a little. 0:09:12.960 --> 0:09:15.559 So imagine you've got a graph to show off sound 0:09:15.559 --> 0:09:17.880 in this way. Right, you're just looking at a graph. 0:09:18.080 --> 0:09:20.840 You've got a point that represents an object, and then 0:09:20.880 --> 0:09:23.560 you would draw circles around it to represent the sound 0:09:23.600 --> 0:09:26.920 waves emanating outward from that object. Well, if you were 0:09:27.240 --> 0:09:29.760 to imagine that this object is moving, let's say it's 0:09:29.760 --> 0:09:32.480 moving in a straight line towards the right side of 0:09:32.480 --> 0:09:36.440 the graph, if you wanted to represent the sound waves 0:09:36.440 --> 0:09:41.120 of circles, Now those circles would be offset. They would 0:09:41.120 --> 0:09:44.560 no longer be centered around that point. The point would 0:09:44.600 --> 0:09:47.640 be closer to the right side of those circles. The 0:09:47.679 --> 0:09:50.080 circles would be bunched up a little bit on the 0:09:50.160 --> 0:09:53.360 right and spread out a little bit on the left. Uh. 0:09:53.480 --> 0:09:54.720 You can think of it as like a stack of 0:09:54.760 --> 0:09:57.680 plates where you've shifted all the plates over, like each 0:09:57.679 --> 0:09:59.839 plate is slightly smaller than the one under it, and 0:10:00.080 --> 0:10:02.199 shifted them all over to the right a little bit. 0:10:03.640 --> 0:10:06.400 This means that if you were standing in the path 0:10:07.040 --> 0:10:10.240 of that object, as it got closer to you, as 0:10:10.240 --> 0:10:11.959 you would hear the sound, you would hear it at 0:10:11.960 --> 0:10:15.760 a higher pitch the sound waves. The wavelength between the 0:10:15.800 --> 0:10:18.920 sound waves has been compressed. That means it comes in 0:10:18.960 --> 0:10:21.360 at a higher frequency or a higher pitch as we 0:10:21.400 --> 0:10:25.120 would perceive it. Then when the object would pass because 0:10:25.160 --> 0:10:29.520 the sound waves are further apart from each other, that 0:10:29.559 --> 0:10:31.360 would come in as a lower pitch. This is the 0:10:31.400 --> 0:10:35.760 Doppler effect. So that's that now sound you always hear 0:10:35.800 --> 0:10:38.200 when something's coming at you and then passes you very quickly. 0:10:38.960 --> 0:10:41.199 If the object is moving at the speed of sound, 0:10:41.640 --> 0:10:45.920 then all the sound waves get compressed at that point 0:10:45.960 --> 0:10:49.319 of where the object is as it's moving. Uh. You know, again, 0:10:49.360 --> 0:10:51.040 if we say it's moving in a straight line to 0:10:51.080 --> 0:10:53.679 the right, all the edges of all the circles are 0:10:53.760 --> 0:10:58.280 overlapping right there at that point. This is the point 0:10:58.320 --> 0:11:00.880 of the shock wave. So let's say you can see 0:11:00.920 --> 0:11:04.880 this object. It's coming towards you. It's not at you yet, 0:11:04.920 --> 0:11:07.679 but you can see it. When you see it, you 0:11:07.679 --> 0:11:11.200 would not hear it make any sound because it's moving 0:11:11.240 --> 0:11:13.840 just as fast as the sound it is generating, so 0:11:13.920 --> 0:11:16.000 you won't hear it until it gets to you. And 0:11:16.040 --> 0:11:18.760 when it gets to you, all of those compressed waves 0:11:18.760 --> 0:11:21.600 would hit you at the same time. This is a 0:11:21.640 --> 0:11:24.840 sonic boom. It's when all the sound that would have 0:11:24.880 --> 0:11:28.160 been spread out as the object got closer to you 0:11:28.520 --> 0:11:31.360 has hits you, hits you all at once, so all 0:11:31.360 --> 0:11:35.400 those waves hit you simultaneously, and you get the sonic boom. Now, 0:11:35.480 --> 0:11:38.840 if the object is actually moving faster than sound, then 0:11:38.880 --> 0:11:42.560 it has behind it a cone of sound waves. The 0:11:42.559 --> 0:11:45.680 object is no longer even making contact with those circles. 0:11:45.679 --> 0:11:47.559 If we're if we're to draw it on a graph, 0:11:47.960 --> 0:11:50.280 you would have an object to the right and a 0:11:50.280 --> 0:11:54.679 series of circles that are semi overlapping and getting larger 0:11:54.679 --> 0:11:56.920 and larger as you go further to the left, and 0:11:56.960 --> 0:11:59.160 if you were to draw enough of them and then 0:11:59.280 --> 0:12:01.240 draw lines on either side, you would see this makes 0:12:01.240 --> 0:12:04.480 a cone shape. It's actually a three dimensional conical shape 0:12:04.679 --> 0:12:07.360 spreading in all directions. The faster the object is going, 0:12:07.400 --> 0:12:10.880 the pointier the cone is going to be. When that 0:12:11.080 --> 0:12:16.600 cone makes contact with a listener, that's when the listener 0:12:16.640 --> 0:12:20.360 would hear the shock wave or experience the shockwave the 0:12:20.360 --> 0:12:24.320 sonic boom, So the object would actually pass the person 0:12:24.559 --> 0:12:28.599 completely before the person would hear the sonic boom. In 0:12:28.640 --> 0:12:31.240 this case, because the objects moving faster than sound is 0:12:32.080 --> 0:12:34.760 uh that cone will trail behind the object as long 0:12:34.800 --> 0:12:37.760 as it's traveling at this speed, So if you're in 0:12:37.800 --> 0:12:40.000 the path of the cone, you'll hear the boom once 0:12:40.040 --> 0:12:43.640 the cones border crosses you. If you could then immediately 0:12:43.679 --> 0:12:47.360 teleport ahead of the traveling object so that the cone 0:12:47.360 --> 0:12:49.800 would pass over you again, you would hear it again 0:12:50.040 --> 0:12:52.920 once it passed over you. The so the cone represents 0:12:52.960 --> 0:12:56.320 the crests of many waves of sound, and also within 0:12:56.360 --> 0:12:58.679 that cone, you have a rapid change of air pressure 0:12:58.679 --> 0:13:01.880 and temperature, meaning any air vehicle that's going to be 0:13:01.920 --> 0:13:04.240 traveling at the speed of sound or greater has to 0:13:04.240 --> 0:13:07.600 be able to handle these major changes in those factors. 0:13:08.320 --> 0:13:11.920 NASA is currently working on developing a low boom supersonic aircraft, 0:13:11.960 --> 0:13:14.960 which will use special aircraft shapes meant to limit the 0:13:15.000 --> 0:13:18.080 intensity of the sonic booms they will generate, but that's 0:13:18.080 --> 0:13:21.640 a topic for a future episode. In the then Soviet Union, 0:13:21.880 --> 0:13:25.000 two engineers created a design later called the v K 0:13:25.440 --> 0:13:30.280 A Maya ziv Chev And I know I've totally butchered that, 0:13:30.360 --> 0:13:32.959 but you know, you've got to kind of roll with it. 0:13:32.960 --> 0:13:35.040 It was also known as the M forty eight. Uh. 0:13:35.160 --> 0:13:38.040 It was designed to be a really tiny, one person 0:13:38.160 --> 0:13:40.800 space plane that would use an ICYB M as the 0:13:40.920 --> 0:13:43.520 launch vehicle. So how tiny am I talking about? Well, 0:13:43.600 --> 0:13:46.520 it was supposed to be eleven point four feet tall 0:13:46.720 --> 0:13:49.040 or three and a half meters and have a wingspan 0:13:49.080 --> 0:13:51.520 of twelve point four ft or three point eight meters, 0:13:51.920 --> 0:13:54.160 and it would weigh two thousand, two hundred pounds or 0:13:54.200 --> 0:13:58.120 a thousand kilograms. That spacecraft was never built. Several other 0:13:58.200 --> 0:14:02.240 designs would follow, but they two remained almost just completely 0:14:02.240 --> 0:14:05.040 in concept mode. Well, only a few ever reaching the 0:14:05.040 --> 0:14:08.720 earliest stages of prototypes. None flew at that time, the 0:14:08.800 --> 0:14:14.400 so Union would instead focus on ballistic based re entry vehicles, 0:14:14.440 --> 0:14:18.800 not not flying ones. In the United States, NASA has 0:14:18.840 --> 0:14:21.600 a series of air and spacecraft that fall under the 0:14:21.640 --> 0:14:25.280 designation of the X series, and that stands for experimental. 0:14:25.600 --> 0:14:27.800 These are vehicles that are meant to test designs and 0:14:27.840 --> 0:14:31.720 technologies that might be implemented in future aircraft or rockets 0:14:31.800 --> 0:14:35.120 or spacecraft. It's a testing bed for those technologies. The 0:14:35.320 --> 0:14:38.440 X one, fittingly was the first of those vehicles. And 0:14:38.440 --> 0:14:40.920 while the X one was not a space plane, it 0:14:41.040 --> 0:14:43.880 was an important aircraft. For one thing, the X one 0:14:43.880 --> 0:14:46.360 would become the first aircraft to break the sound barrier. 0:14:46.800 --> 0:14:49.400 It was also a purely experimental craft. There were no 0:14:49.480 --> 0:14:53.400 commercial or military or requirements attached to it, so NASA 0:14:53.440 --> 0:14:56.240 was able to focus just on creating the machine that 0:14:56.280 --> 0:14:58.520 would do what they wanted it to do. They didn't 0:14:58.520 --> 0:15:01.640 have to worry about any other cerns and it would 0:15:01.640 --> 0:15:05.200 be up to later designers to incorporate that technology into 0:15:05.280 --> 0:15:08.280 practical aircraft. And I'll have to do a full episode 0:15:08.280 --> 0:15:09.640 on the X one in the future. It is a 0:15:09.640 --> 0:15:12.040 fascinating story, but for our purposes, the important thing to 0:15:12.080 --> 0:15:14.400 keep in mind is that set the stage for later 0:15:14.520 --> 0:15:19.080 experimental aircraft, including some that were essentially prototypes of practical 0:15:19.160 --> 0:15:21.720 vehicles further down the road. I'll tell you about them 0:15:21.720 --> 0:15:23.600 in just a second, but first let's take a quick 0:15:23.640 --> 0:15:34.560 break to thank our sponsor. There have been many different 0:15:34.880 --> 0:15:37.240 X vehicles. All of them were meant to work on 0:15:37.400 --> 0:15:41.920 different designs and strategies like wing shape, aircraft, material, power systems, 0:15:41.920 --> 0:15:45.880 propulsion systems, and experimental techniques like vertical takeoff and landing. 0:15:46.080 --> 0:15:49.360 And to be honest, most of those have contributed in 0:15:49.400 --> 0:15:53.040 some way or another toward the development of space planes, 0:15:53.120 --> 0:15:55.400 either directly or indirectly. But if I were to go 0:15:55.480 --> 0:15:58.080 down the whole list and explain each one, we would 0:15:58.120 --> 0:16:01.160 have at least another week's worth of episodes to get through. 0:16:01.280 --> 0:16:03.320 So I'm just gonna hit some of the highlights that 0:16:03.360 --> 0:16:06.280 I feel are particularly relevant. But please keep in mind 0:16:06.840 --> 0:16:09.880 this is like the cliffs Notes version of space plane history. 0:16:10.320 --> 0:16:14.320 The X fifteen was a hypersonic research jet plane program 0:16:14.440 --> 0:16:17.280 NASA partnered with the U. S. Navy, the US Air Force, 0:16:17.320 --> 0:16:21.000 and a company called North American Aviation Incorporated. The aircraft 0:16:21.040 --> 0:16:23.960 traveled at a top speed of four thousand, five hundred 0:16:24.040 --> 0:16:27.480 twenty miles per hour. That's seven thousand, two hundred seventy 0:16:27.560 --> 0:16:31.680 five kilometers per hour, also known as mock six point 0:16:32.000 --> 0:16:36.040 seven well also known as is being too glib and 0:16:36.120 --> 0:16:40.040 not entirely accurate, because mack is a way of expressing 0:16:40.080 --> 0:16:43.960 speed in relation to the speed of sound moving through air. Now, 0:16:44.000 --> 0:16:46.360 this gets a little complicated because, like I said earlier, 0:16:46.400 --> 0:16:49.720 sound will travel at different speeds depending upon different factors 0:16:49.760 --> 0:16:53.680 like air temperature. So sound moves at a at one 0:16:53.720 --> 0:16:56.480 speed through cold air and a different speed through warm air. 0:16:57.080 --> 0:17:00.240 And that's because sound is a physical phenomenon and involves 0:17:00.440 --> 0:17:04.480 vibrating molecules. But the mock number actually takes that into account. 0:17:04.960 --> 0:17:07.760 The mock number is the ratio that describes the speed 0:17:07.880 --> 0:17:10.760 of a given thing. Typically we call it flow, but 0:17:10.800 --> 0:17:15.360 again it could be an object, uh and within an environment. 0:17:15.359 --> 0:17:17.840 So in this case, we're talking about aircraft, and you 0:17:17.880 --> 0:17:21.040 compare that with respect the speed of sound within the 0:17:21.119 --> 0:17:24.760 same medium under the same conditions. So if I say 0:17:24.760 --> 0:17:27.840 an aircraft travels at MOCK one, I wouldn't be saying 0:17:27.880 --> 0:17:30.280 that it's going just as fast as the speed of 0:17:30.320 --> 0:17:33.600 sound within that medium, meaning the air that the aircraft 0:17:33.640 --> 0:17:36.800 is traveling through. Now, the one I just mentioned before, 0:17:36.880 --> 0:17:40.240 the X fifteen was mock six point seven. That means 0:17:40.280 --> 0:17:42.160 that the X fifteen could travel up to six point 0:17:42.240 --> 0:17:45.480 seven times faster than the speed of sound through that 0:17:45.600 --> 0:17:49.479 same medium, which is wicked fast. There were three X 0:17:49.520 --> 0:17:55.520 fifteen rocket planes collectively, they flew one hundred ninety nine times. 0:17:55.960 --> 0:17:58.040 The X fifteen did not take off on the ground 0:17:58.119 --> 0:18:01.040 on its own, nor was it launched via rocket. Instead, 0:18:01.640 --> 0:18:04.760 it would launch from a B fifty two aircraft at 0:18:04.760 --> 0:18:07.639 around an altitude of forty five thousand feet there's about 0:18:07.680 --> 0:18:12.440 thirteen thousand, seven sixteen, and the B fifty two would 0:18:12.440 --> 0:18:14.160 be traveling at a speed of around five hundred miles 0:18:14.240 --> 0:18:17.800 pur or eight hundred five kilometers per hour. The highest 0:18:17.840 --> 0:18:21.159 altitude the X fifteen ever reached, according to NASA, was 0:18:21.240 --> 0:18:25.359 three fifty four thousand, two hundred feet that's sixty seven 0:18:25.480 --> 0:18:29.680 miles or one eight kilometers. The Carmen line, which most 0:18:29.720 --> 0:18:32.119 of the world acknowledges as being the border line for 0:18:32.280 --> 0:18:36.800 Earth's atmosphere and space, is generally in the one kilometer 0:18:36.880 --> 0:18:41.320 altitude range, So the X fifteen reached altitudes of suborbital space, 0:18:41.880 --> 0:18:43.879 so you could argue the X fifteen qualifies as a 0:18:43.920 --> 0:18:47.080 space plane, but one that was meant purely to conduct 0:18:47.160 --> 0:18:51.280 research for future vehicle designs. Following the X fifteen was 0:18:51.359 --> 0:18:55.760 a project called the Dina sore d Y in a 0:18:56.160 --> 0:18:59.720 Dash s O A R, also known as the X twenty. 0:19:00.200 --> 0:19:03.760 NASA contracted Boeing to build the space plane. There was 0:19:03.800 --> 0:19:07.840 a related asset called Asset. This was sort of the 0:19:08.080 --> 0:19:11.800 nose cone section of the dinosaur. It was used separately 0:19:11.880 --> 0:19:15.399 to test various designs to find out what sort of 0:19:15.480 --> 0:19:19.080 shielding would best withstand re entry and the rigors that 0:19:19.560 --> 0:19:22.040 any material would undergo as it does re enter the 0:19:22.080 --> 0:19:25.680 air's atmosphere. The Dinosaur was in parallel development in some 0:19:25.800 --> 0:19:28.240 ways to the X fifteen that it would take advantage 0:19:28.240 --> 0:19:31.359 of lessons learned from the X fifteen program, and it 0:19:31.560 --> 0:19:35.360 also had links back to the silver Vogel aircraft proposed 0:19:35.400 --> 0:19:38.800 in Germany. There was a man named Walter Dornburger or 0:19:38.920 --> 0:19:41.480 Valter Dornburger. He was one of the key figures in 0:19:41.560 --> 0:19:45.000 developing the Dinosaur project. He was in charge of Germany's 0:19:45.119 --> 0:19:48.080 rocketry program in World War Two. He was also the 0:19:48.119 --> 0:19:52.639 direct superior to the famous rocket scientist Verna von Brown. 0:19:53.359 --> 0:19:56.479 He wasn't picked up by the United States during Project 0:19:56.560 --> 0:19:59.359 paper Clip. That was the secret project in which the 0:19:59.440 --> 0:20:01.879 United States out over a whole bunch of German scientists 0:20:02.359 --> 0:20:04.120 to work on the same stuff they had been doing 0:20:04.200 --> 0:20:07.040 over in Germany, but now for the United States. Dorn 0:20:07.080 --> 0:20:10.919 Burger instead go into British custody for a few years 0:20:11.600 --> 0:20:13.960 before being released and then immigrating to the United States, 0:20:14.000 --> 0:20:16.959 where he found a job with Bell Aircraft. He advocated 0:20:17.000 --> 0:20:19.639 that the company tried to make real the vision of 0:20:19.800 --> 0:20:23.320 the Silver Vocal. Dorn Burger felt that rockets were the 0:20:23.400 --> 0:20:27.119 future of flight, even for commercial flight, though probably just 0:20:27.320 --> 0:20:29.880 for the really wealthy, and it would become the propulsion 0:20:29.920 --> 0:20:32.160 systems for a new type of aircraft that he would 0:20:32.200 --> 0:20:36.480 call ultra planes. These were essentially very similar to what 0:20:36.640 --> 0:20:39.080 we would think of as space planes, and dorn Berger 0:20:39.160 --> 0:20:42.400 imagined a world in which a hypersonic glider would ride 0:20:42.440 --> 0:20:47.359 piggyback on a larger rocket propelled aircraft. At the appropriate altitude, 0:20:47.680 --> 0:20:50.600 the glider would launch off of rails that were mounted 0:20:50.720 --> 0:20:54.399 on this booster vehicle and ignite its own rocket propulsion system, 0:20:54.440 --> 0:20:57.600 which would push this smaller vehicle to great speed and 0:20:57.720 --> 0:21:00.359 higher altitudes. At the peak of its journey, It would 0:21:00.359 --> 0:21:03.280 then switch off its engines and then glide quietly to 0:21:03.400 --> 0:21:07.639 its destination. The booster vehicle would return home for the 0:21:07.800 --> 0:21:10.920 next journey up, and this idea would coalesce into a 0:21:11.000 --> 0:21:15.200 program that was called Dinosaur. As one of several proposals 0:21:15.440 --> 0:21:19.240 that entered into debate during the Round three conference, which 0:21:19.280 --> 0:21:22.040 took place just eleven days after the Soviet Union had 0:21:22.080 --> 0:21:27.160 successfully launched Spot Nick one into orbit. Dinosaur, which originally 0:21:27.240 --> 0:21:30.600 was pitched as a dual research and military platform that 0:21:30.800 --> 0:21:33.760 could potentially be weaponized, was able to move into the 0:21:33.840 --> 0:21:38.240 next stage of development. The program was actually revised multiple times, 0:21:38.560 --> 0:21:41.720 and this complicated the process of designing and prototyping because 0:21:41.720 --> 0:21:45.440 whenever you change the requirements, it changes lots of other 0:21:45.680 --> 0:21:49.119 stuff down the line. One late edition was a feasibility 0:21:49.160 --> 0:21:51.760 study to make sure that the Dinosaur could also serve 0:21:51.920 --> 0:21:54.840 as an orbital vehicle, sort of like what the Space 0:21:54.840 --> 0:22:00.000 Shuttle would eventually become. Then in September, the United States 0:22:00.000 --> 0:22:04.480 SARA Force General Bernard A. Shriver changed things up big 0:22:04.560 --> 0:22:07.440 time by stating the program would be split into two 0:22:08.280 --> 0:22:12.440 parallel arms. One of the versions of Dinosaur would be 0:22:12.880 --> 0:22:15.919 developed as a military application of the technology. The other 0:22:16.000 --> 0:22:19.280 would be intended for space faring projects, and a priority 0:22:19.359 --> 0:22:23.040 would be placed on No big surprise here the military one. 0:22:23.520 --> 0:22:26.800 Around this time, pilots were joining the program, including future 0:22:26.840 --> 0:22:30.600 astronaut Neil Armstrong. Armstrong was also given the task to 0:22:30.640 --> 0:22:34.280 figure out how to keep an astronaut safe in the 0:22:34.359 --> 0:22:37.840 event of a launch failure, such as a launch vehicle 0:22:38.240 --> 0:22:41.560 about to explode. Ejection was not an option because the 0:22:41.640 --> 0:22:45.720 dinosaur cockpit was only about a hundred feet above the 0:22:45.800 --> 0:22:48.680 ground in the design they had created. Once it was 0:22:48.720 --> 0:22:51.840 attached to a launch vehicle, and the pilot would be 0:22:52.400 --> 0:22:56.240 essentially on his or her back UH in a seated position, 0:22:56.359 --> 0:23:00.600