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Speaker 1: Get in touch with technology with tech Stuff from how

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Speaker 1: stuff Works dot com. Hey there, and welcome to tech Stuff.

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Speaker 1: I'm your host, Jonathan Strickland. I'm an executive producer with

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Speaker 1: How Stuff Works and I love all things tech and

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Speaker 1: listener Ivan wrote into me and asked if I might

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Speaker 1: record an episode about space planes. So today and tomorrow

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Speaker 1: we're going to learn about space planes, because it turns

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Speaker 1: out it's a big enough topic to warrant two episodes.

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Speaker 1: We're gonna learn more or less how they work, why

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Speaker 1: anyone was interested in building them, and some of the

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Speaker 1: past and current projects that fall into that category. So

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Speaker 1: to begin with, what the heck is a space plane? Well,

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Speaker 1: like most stuff that has to do with space exploration,

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Speaker 1: it's complicated. The general concept, if you're going super super

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Speaker 1: high level, is that a space plane is a vehicle

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Speaker 1: that can go into space, not necessarily into orbit, but

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Speaker 1: at least into space and return to Earth, and it

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Speaker 1: can fly under its own power. That's in contrast with

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Speaker 1: other space vehicles like the Apollo or the soy US.

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Speaker 1: Those have the tried and true methodology of ballistic re entry,

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Speaker 1: also known as plummeting towards Earth under the force of

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Speaker 1: gravity and then deploying a parachute to slow you down,

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Speaker 1: and in the case of the soy Us, also having

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Speaker 1: a quick blast of a retro rocket before you touch down,

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Speaker 1: either in the ocean or on terra firma. A space

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Speaker 1: plane would re enter Earth's atmosphere and then use the

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Speaker 1: principles of powered flight or powered gliding to land at

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Speaker 1: a designated landing strip, so they could actually not just

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Speaker 1: control their descent, but steer and and go to a

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Speaker 1: specific location for landing. This is actually way more complicated

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Speaker 1: that I'm letting on at this stage, because you have

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Speaker 1: to remember the principles of flight in space are very

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Speaker 1: different than the principles of light. Here in the atmosphere

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Speaker 1: of Earth. You have a fluid dynamics that work when

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Speaker 1: you're flying through an atmosphere, and then you have the

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Speaker 1: near vacuum of space when you're out in space. So,

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Speaker 1: despite what science fiction films like Star Wars would have

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Speaker 1: us believe, you wouldn't bank in outer space because there'd

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Speaker 1: be no atmosphere for you to bank off of. In

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Speaker 1: addition to these basic concepts I've just mentioned, we tend

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Speaker 1: to tie to other things to the idea of space planes.

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Speaker 1: One is that they should be reusable, meaning that you

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Speaker 1: would refurbish a space plane after it's gone on a mission,

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Speaker 1: and then you could use that exact same vehicle and

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Speaker 1: a future mission, and that cuts down costs because you

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Speaker 1: don't have to build a whole new one. The second

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Speaker 1: big thing is that they should be easy and by

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Speaker 1: that I mean cheaper to launch into space compared to

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Speaker 1: other spacecraft. That's ideal. If you can figure out a

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Speaker 1: way to make it easier to launch these types of

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Speaker 1: spacecraft into space, you again bring down the cost of

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Speaker 1: getting stuff into space. Under these general guidelines, you could

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Speaker 1: say the space Shuttle qualifies as a space plane that

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Speaker 1: totally is a type of space plane. It was reusable,

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Speaker 1: it could return to Earth and powered glide so it

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Speaker 1: can navigate to a specific landing strip. But the history

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Speaker 1: of space planes dates way earlier than the Space Shuttle program.

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Speaker 1: Perhaps the earliest design for a space plane would be

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Speaker 1: the Silver Focal or silver Bird design. This was a

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Speaker 1: proposal that dated in to the nineteen forties and it

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Speaker 1: was in Germany during World War Two. The design was

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Speaker 1: essentially a liquid fueled rocket that had some wings attached

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Speaker 1: to it that was meant for a German pilot to

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Speaker 1: fly up high into the atmosphere, essentially entering into what

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Speaker 1: we would consider to be space, but not orbit. It

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Speaker 1: would be a suborbital flight then to cross the Atlantic

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Speaker 1: Ocean and descend in a a powered glide to attack

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Speaker 1: a target in America like New York City. Now, while

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Speaker 1: the Germans built some mock ups of this design, including

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Speaker 1: one to use in wind tunnels, to make sure that

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Speaker 1: the actual physical design of the body made sense, ultimately

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Speaker 1: engineers concluded that it was too complicated to advanced to

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Speaker 1: make practical. They just weren't quite there technologically to make

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Speaker 1: it a practicality. But we'll revisit this concept shortly. In

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Speaker 1: the nineteen fifties, a British engineer named Terrence non Wiler

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Speaker 1: proposed an interesting concept called wave riding that would find

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Speaker 1: its way into various space plane proposals. That started with

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Speaker 1: a wing design called the carrot wing, which is a

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Speaker 1: wing that has a type of concave pyramids shape to it.

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Speaker 1: Non Wiler worked out a physical design that would allow

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Speaker 1: an aircraft traveling at supersonic speeds to leverage the shock

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Speaker 1: waves it was actually generating and use that as a

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Speaker 1: lifting surface, which to me is incredible. That actually everything

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Speaker 1: that has to do with supersonic and hypersonic flight physics

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Speaker 1: to me is amazing. So what does that actually mean?

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Speaker 1: Was a shock wave? Why do those things happen? Well,

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Speaker 1: shock wave is a phenomenon that happens with really any

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Speaker 1: type of wave, but we're specifically talking about sound waves here.

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Speaker 1: When in a flow moves higher than the speed of

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Speaker 1: sound in a given medium, and by flow I typically

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Speaker 1: mean an object like an aircraft, but it could be

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Speaker 1: other things. In fact, it could even be um the

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Speaker 1: air itself moving faster than the speed of sound. So

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Speaker 1: a cracking whip generates a small shock wave, a small

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Speaker 1: little sonic boom type thing at the tip of the

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Speaker 1: whip because it moves faster than the speed of sound

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Speaker 1: when you crack it. So when you hear someone crack

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Speaker 1: a whip, that means the very tip of that whip

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Speaker 1: when it made that snap, was traveling faster than the

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Speaker 1: speed of sound was. So let's get an understanding what's

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Speaker 1: going on from a physics point of view. First, when

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Speaker 1: something makes a sound, it's a physical phenomenon, right, It's

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Speaker 1: it's the changing of pressure of uh air. Essentially air molecules.

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Speaker 1: It's pushing them together or creating gaps and thus creating

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Speaker 1: kind of a vacuum between them, and this propagates outward

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Speaker 1: from the source. So we can visualize the sound wave

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Speaker 1: as a sphere that's moving outward from something that's making

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Speaker 1: the noise. So you've got a central object. Let's say

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Speaker 1: it's a boom box or I guess if you guys

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Speaker 1: don't know what a boom boxes, it's a it's a stereo,

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Speaker 1: it's a radio, it's a it's a it's a smartphone

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Speaker 1: playing Bruno Mars, it's playing music really loud, and the

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Speaker 1: sound will travel out from a sphere from this central point. Technically,

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Speaker 1: it travels out in all three dimensions, although obviously if

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Speaker 1: you're playing something near the ground, it's gonna be bouncing

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Speaker 1: off the ground at some point. But the sphere size

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Speaker 1: increases at the rate of the speed of sound, right,

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Speaker 1: because sound is traveling outward at the speed of sound,

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Speaker 1: and gradually the that sound wave gets weaker and weaker

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Speaker 1: as it propagates further and further out from the objects.

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Speaker 1: So the further out you are from the object making sound,

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Speaker 1: the quieter it's going to be to you. As the

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Speaker 1: object continues to make sound, it's making more and more

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Speaker 1: sound waves, so they're they're moving outward in this series

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Speaker 1: of spheres that are growing out from the center of

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Speaker 1: this sound storm. So we typically will illustrate this in

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Speaker 1: a two dimensional format. It's much easier to understand that way.

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Speaker 1: So you would just put a central point that would

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Speaker 1: represent whatever the object is it's making sound, a stationary

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Speaker 1: sound source, and you would surround that with a series

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Speaker 1: of concentric circles and uh that suggests a sound wave

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Speaker 1: that's traveling outward from that source, and it's a series

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Speaker 1: of sound waves, actually, each concentric circle being another sound

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Speaker 1: wave in this progression. So the further out you are

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Speaker 1: from the object, the closer you are to the largest

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Speaker 1: part of that of those circles. At this stage where

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Speaker 1: you have an object making noise and it's stationary, all

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Speaker 1: of the sounds are moving outward from the source and

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Speaker 1: an equal rate of speed hitting things that are equidistant

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Speaker 1: from the object at the same time. So if you

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Speaker 1: were standing five ft to the right of the object,

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Speaker 1: I'm standing five feet to the left of the object.

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Speaker 1: The object is perfectly still. We're both gonna get hit

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Speaker 1: by those sound waves at the same time we are equidistant.

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Speaker 1: Sound is traveling at a uh standard speed and which

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Speaker 1: is dependent upon the pressure and temperature and some other

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Speaker 1: stuff in the air, but it's going to be traveling

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Speaker 1: at that same speed through that medium. We're gonna hear

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Speaker 1: at the same time. If I'm standing ten ft away

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Speaker 1: and you're standing five feet away, it's gonna take longer

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Speaker 1: for those sound waves to hit me then hit you.

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Speaker 1: Not a whole lot longer, because the speed of sound

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Speaker 1: is pretty fast, but technically it'll take a little longer

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Speaker 1: to hit me than it does to hit you. If

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Speaker 1: the object isn't stationary, then the picture changes a little.

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Speaker 1: So imagine you've got a graph to show off sound

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Speaker 1: in this way. Right, you're just looking at a graph.

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Speaker 1: You've got a point that represents an object, and then

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Speaker 1: you would draw circles around it to represent the sound

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Speaker 1: waves emanating outward from that object. Well, if you were

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Speaker 1: to imagine that this object is moving, let's say it's

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Speaker 1: moving in a straight line towards the right side of

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Speaker 1: the graph, if you wanted to represent the sound waves

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Speaker 1: of circles, Now those circles would be offset. They would

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Speaker 1: no longer be centered around that point. The point would

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Speaker 1: be closer to the right side of those circles. The

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Speaker 1: circles would be bunched up a little bit on the

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Speaker 1: right and spread out a little bit on the left. Uh.

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Speaker 1: You can think of it as like a stack of

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Speaker 1: plates where you've shifted all the plates over, like each

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Speaker 1: plate is slightly smaller than the one under it, and

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Speaker 1: shifted them all over to the right a little bit.

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Speaker 1: This means that if you were standing in the path

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Speaker 1: of that object, as it got closer to you, as

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Speaker 1: you would hear the sound, you would hear it at

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Speaker 1: a higher pitch the sound waves. The wavelength between the

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Speaker 1: sound waves has been compressed. That means it comes in

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Speaker 1: at a higher frequency or a higher pitch as we

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Speaker 1: would perceive it. Then when the object would pass because

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Speaker 1: the sound waves are further apart from each other, that

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Speaker 1: would come in as a lower pitch. This is the

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Speaker 1: Doppler effect. So that's that now sound you always hear

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Speaker 1: when something's coming at you and then passes you very quickly.

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Speaker 1: If the object is moving at the speed of sound,

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Speaker 1: then all the sound waves get compressed at that point

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Speaker 1: of where the object is as it's moving. Uh. You know, again,

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Speaker 1: if we say it's moving in a straight line to

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Speaker 1: the right, all the edges of all the circles are

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Speaker 1: overlapping right there at that point. This is the point

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Speaker 1: of the shock wave. So let's say you can see

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Speaker 1: this object. It's coming towards you. It's not at you yet,

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Speaker 1: but you can see it. When you see it, you

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Speaker 1: would not hear it make any sound because it's moving

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Speaker 1: just as fast as the sound it is generating, so

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Speaker 1: you won't hear it until it gets to you. And

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Speaker 1: when it gets to you, all of those compressed waves

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Speaker 1: would hit you at the same time. This is a

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Speaker 1: sonic boom. It's when all the sound that would have

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Speaker 1: been spread out as the object got closer to you

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Speaker 1: has hits you, hits you all at once, so all

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Speaker 1: those waves hit you simultaneously, and you get the sonic boom. Now,

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Speaker 1: if the object is actually moving faster than sound, then

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Speaker 1: it has behind it a cone of sound waves. The

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Speaker 1: object is no longer even making contact with those circles.

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Speaker 1: If we're if we're to draw it on a graph,

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Speaker 1: you would have an object to the right and a

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Speaker 1: series of circles that are semi overlapping and getting larger

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Speaker 1: and larger as you go further to the left, and

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Speaker 1: if you were to draw enough of them and then

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Speaker 1: draw lines on either side, you would see this makes

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Speaker 1: a cone shape. It's actually a three dimensional conical shape

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Speaker 1: spreading in all directions. The faster the object is going,

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Speaker 1: the pointier the cone is going to be. When that

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Speaker 1: cone makes contact with a listener, that's when the listener

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Speaker 1: would hear the shock wave or experience the shockwave the

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Speaker 1: sonic boom, So the object would actually pass the person

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Speaker 1: completely before the person would hear the sonic boom. In

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Speaker 1: this case, because the objects moving faster than sound is

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Speaker 1: uh that cone will trail behind the object as long

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Speaker 1: as it's traveling at this speed, So if you're in

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Speaker 1: the path of the cone, you'll hear the boom once

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Speaker 1: the cones border crosses you. If you could then immediately

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Speaker 1: teleport ahead of the traveling object so that the cone

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Speaker 1: would pass over you again, you would hear it again

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Speaker 1: once it passed over you. The so the cone represents

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Speaker 1: the crests of many waves of sound, and also within

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Speaker 1: that cone, you have a rapid change of air pressure

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Speaker 1: and temperature, meaning any air vehicle that's going to be

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Speaker 1: be able to handle these major changes in those factors.

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Speaker 1: NASA is currently working on developing a low boom supersonic aircraft,

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Speaker 1: which will use special aircraft shapes meant to limit the

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Speaker 1: intensity of the sonic booms they will generate, but that's

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Speaker 1: a topic for a future episode. In the then Soviet Union,

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Speaker 1: two engineers created a design later called the v K

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Speaker 1: A Maya ziv Chev And I know I've totally butchered that,

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Speaker 1: but you know, you've got to kind of roll with it.

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Speaker 1: It was also known as the M forty eight. Uh.

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Speaker 1: It was designed to be a really tiny, one person

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Speaker 1: space plane that would use an ICYB M as the

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Speaker 1: launch vehicle. So how tiny am I talking about? Well,

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Speaker 1: it was supposed to be eleven point four feet tall

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Speaker 1: or three and a half meters and have a wingspan

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Speaker 1: of twelve point four ft or three point eight meters,

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Speaker 1: and it would weigh two thousand, two hundred pounds or

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Speaker 1: a thousand kilograms. That spacecraft was never built. Several other

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Speaker 1: designs would follow, but they two remained almost just completely

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Speaker 1: in concept mode. Well, only a few ever reaching the

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Speaker 1: earliest stages of prototypes. None flew at that time, the

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Speaker 1: so Union would instead focus on ballistic based re entry vehicles,

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Speaker 1: not not flying ones. In the United States, NASA has

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Speaker 1: a series of air and spacecraft that fall under the

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Speaker 1: designation of the X series, and that stands for experimental.

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Speaker 1: These are vehicles that are meant to test designs and

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Speaker 1: technologies that might be implemented in future aircraft or rockets

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Speaker 1: or spacecraft. It's a testing bed for those technologies. The

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Speaker 1: X one, fittingly was the first of those vehicles. And

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Speaker 1: while the X one was not a space plane, it

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Speaker 1: was an important aircraft. For one thing, the X one

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Speaker 1: would become the first aircraft to break the sound barrier.

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Speaker 1: It was also a purely experimental craft. There were no

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Speaker 1: commercial or military or requirements attached to it, so NASA

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Speaker 1: was able to focus just on creating the machine that

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Speaker 1: would do what they wanted it to do. They didn't

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Speaker 1: have to worry about any other cerns and it would

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Speaker 1: be up to later designers to incorporate that technology into

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Speaker 1: practical aircraft. And I'll have to do a full episode

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Speaker 1: on the X one in the future. It is a

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Speaker 1: fascinating story, but for our purposes, the important thing to

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Speaker 1: keep in mind is that set the stage for later

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Speaker 1: experimental aircraft, including some that were essentially prototypes of practical

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Speaker 1: vehicles further down the road. I'll tell you about them

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Speaker 1: in just a second, but first let's take a quick

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Speaker 1: break to thank our sponsor. There have been many different

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Speaker 1: X vehicles. All of them were meant to work on

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Speaker 1: different designs and strategies like wing shape, aircraft, material, power systems,

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Speaker 1: propulsion systems, and experimental techniques like vertical takeoff and landing.

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Speaker 1: And to be honest, most of those have contributed in

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Speaker 1: some way or another toward the development of space planes,

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Speaker 1: either directly or indirectly. But if I were to go

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Speaker 1: down the whole list and explain each one, we would

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Speaker 1: have at least another week's worth of episodes to get through.

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Speaker 1: So I'm just gonna hit some of the highlights that

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Speaker 1: I feel are particularly relevant. But please keep in mind

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Speaker 1: this is like the cliffs Notes version of space plane history.

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Speaker 1: The X fifteen was a hypersonic research jet plane program

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Speaker 1: NASA partnered with the U. S. Navy, the US Air Force,

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Speaker 1: and a company called North American Aviation Incorporated. The aircraft

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Speaker 1: traveled at a top speed of four thousand, five hundred

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Speaker 1: twenty miles per hour. That's seven thousand, two hundred seventy

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Speaker 1: five kilometers per hour, also known as mock six point

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Speaker 1: seven well also known as is being too glib and

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Speaker 1: not entirely accurate, because mack is a way of expressing

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Speaker 1: speed in relation to the speed of sound moving through air. Now,

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Speaker 1: this gets a little complicated because, like I said earlier,

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Speaker 1: sound will travel at different speeds depending upon different factors

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Speaker 1: like air temperature. So sound moves at a at one

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Speaker 1: speed through cold air and a different speed through warm air.

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Speaker 1: And that's because sound is a physical phenomenon and involves

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Speaker 1: vibrating molecules. But the mock number actually takes that into account.

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Speaker 1: The mock number is the ratio that describes the speed

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Speaker 1: of a given thing. Typically we call it flow, but

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Speaker 1: again it could be an object, uh and within an environment.

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Speaker 1: So in this case, we're talking about aircraft, and you

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Speaker 1: compare that with respect the speed of sound within the

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Speaker 1: same medium under the same conditions. So if I say

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Speaker 1: an aircraft travels at MOCK one, I wouldn't be saying

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Speaker 1: that it's going just as fast as the speed of

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Speaker 1: sound within that medium, meaning the air that the aircraft

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Speaker 1: is traveling through. Now, the one I just mentioned before,

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Speaker 1: the X fifteen was mock six point seven. That means

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Speaker 1: that the X fifteen could travel up to six point

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Speaker 1: seven times faster than the speed of sound through that

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Speaker 1: same medium, which is wicked fast. There were three X

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Speaker 1: fifteen rocket planes collectively, they flew one hundred ninety nine times.

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Speaker 1: The X fifteen did not take off on the ground

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Speaker 1: on its own, nor was it launched via rocket. Instead,

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Speaker 1: it would launch from a B fifty two aircraft at

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Speaker 1: around an altitude of forty five thousand feet there's about

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Speaker 1: thirteen thousand, seven sixteen, and the B fifty two would

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Speaker 1: be traveling at a speed of around five hundred miles

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Speaker 1: pur or eight hundred five kilometers per hour. The highest

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Speaker 1: altitude the X fifteen ever reached, according to NASA, was

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Speaker 1: three fifty four thousand, two hundred feet that's sixty seven

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Speaker 1: miles or one eight kilometers. The Carmen line, which most

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Speaker 1: of the world acknowledges as being the border line for

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Speaker 1: Earth's atmosphere and space, is generally in the one kilometer

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Speaker 1: altitude range, So the X fifteen reached altitudes of suborbital space,

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Speaker 1: so you could argue the X fifteen qualifies as a

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Speaker 1: space plane, but one that was meant purely to conduct

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Speaker 1: research for future vehicle designs. Following the X fifteen was

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Speaker 1: a project called the Dina sore d Y in a

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Speaker 1: Dash s O A R, also known as the X twenty.

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Speaker 1: NASA contracted Boeing to build the space plane. There was

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Speaker 1: a related asset called Asset. This was sort of the

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Speaker 1: nose cone section of the dinosaur. It was used separately

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Speaker 1: to test various designs to find out what sort of

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Speaker 1: shielding would best withstand re entry and the rigors that

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Speaker 1: any material would undergo as it does re enter the

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Speaker 1: air's atmosphere. The Dinosaur was in parallel development in some

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Speaker 1: ways to the X fifteen that it would take advantage

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Speaker 1: of lessons learned from the X fifteen program, and it

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Speaker 1: also had links back to the silver Vogel aircraft proposed

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Speaker 1: in Germany. There was a man named Walter Dornburger or

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Speaker 1: Valter Dornburger. He was one of the key figures in

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Speaker 1: developing the Dinosaur project. He was in charge of Germany's

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Speaker 1: rocketry program in World War Two. He was also the

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Speaker 1: direct superior to the famous rocket scientist Verna von Brown.

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Speaker 1: He wasn't picked up by the United States during Project

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Speaker 1: paper Clip. That was the secret project in which the

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Speaker 1: United States out over a whole bunch of German scientists

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Speaker 1: to work on the same stuff they had been doing

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Speaker 1: over in Germany, but now for the United States. Dorn

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Speaker 1: Burger instead go into British custody for a few years

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Speaker 1: before being released and then immigrating to the United States,

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Speaker 1: where he found a job with Bell Aircraft. He advocated

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Speaker 1: that the company tried to make real the vision of

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Speaker 1: the Silver Vocal. Dorn Burger felt that rockets were the

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Speaker 1: future of flight, even for commercial flight, though probably just

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Speaker 1: for the really wealthy, and it would become the propulsion

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Speaker 1: systems for a new type of aircraft that he would

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Speaker 1: call ultra planes. These were essentially very similar to what

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Speaker 1: we would think of as space planes, and dorn Berger

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Speaker 1: imagined a world in which a hypersonic glider would ride

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Speaker 1: piggyback on a larger rocket propelled aircraft. At the appropriate altitude,

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Speaker 1: the glider would launch off of rails that were mounted

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Speaker 1: on this booster vehicle and ignite its own rocket propulsion system,

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Speaker 1: which would push this smaller vehicle to great speed and

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Speaker 1: higher altitudes. At the peak of its journey, It would

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Speaker 1: then switch off its engines and then glide quietly to

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Speaker 1: its destination. The booster vehicle would return home for the

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Speaker 1: next journey up, and this idea would coalesce into a

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Speaker 1: program that was called Dinosaur. As one of several proposals

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Speaker 1: that entered into debate during the Round three conference, which

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Speaker 1: took place just eleven days after the Soviet Union had

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Speaker 1: successfully launched Spot Nick one into orbit. Dinosaur, which originally

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Speaker 1: was pitched as a dual research and military platform that

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Speaker 1: could potentially be weaponized, was able to move into the

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Speaker 1: next stage of development. The program was actually revised multiple times,

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Speaker 1: and this complicated the process of designing and prototyping because

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Speaker 1: whenever you change the requirements, it changes lots of other

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Speaker 1: stuff down the line. One late edition was a feasibility

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Speaker 1: study to make sure that the Dinosaur could also serve

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Speaker 1: as an orbital vehicle, sort of like what the Space

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Speaker 1: Shuttle would eventually become. Then in September, the United States

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Speaker 1: SARA Force General Bernard A. Shriver changed things up big

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Speaker 1: time by stating the program would be split into two

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Speaker 1: parallel arms. One of the versions of Dinosaur would be

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Speaker 1: developed as a military application of the technology. The other

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Speaker 1: would be intended for space faring projects, and a priority

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Speaker 1: would be placed on No big surprise here the military one.

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Speaker 1: Around this time, pilots were joining the program, including future

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Speaker 1: astronaut Neil Armstrong. Armstrong was also given the task to

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Speaker 1: figure out how to keep an astronaut safe in the

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Speaker 1: event of a launch failure, such as a launch vehicle

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Speaker 1: about to explode. Ejection was not an option because the

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Speaker 1: dinosaur cockpit was only about a hundred feet above the

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Speaker 1: ground in the design they had created. Once it was

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Speaker 1: attached to a launch vehicle, and the pilot would be

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Speaker 1: essentially on his or her back UH in a seated position,

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Speaker 1: but they're facing upward right the dinosaur would be the

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Speaker 1: nose of the vehicle would be pointing towards the sky.

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Speaker 1: So there wouldn't be enough time if you ejected for

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Speaker 1: the UH for your orientation to change and for the

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Speaker 1: parachute to deploy, and so Armstrong had to come up

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Speaker 1: with a different idea. His solution was to create a

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Speaker 1: system that would actually engage the glider's engine and thus

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Speaker 1: shoot it off of the booster rocket, launching the glider

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Speaker 1: into the sky, and then the pilot would have to

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Speaker 1: take control of this accelerating vehicle and stabilize it and

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Speaker 1: then fly the glider to safety. He was able to

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Speaker 1: do this using a simulated test with an actual jet airplane,

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Speaker 1: and he said he was later on said that he

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Speaker 1: was glad he never had to test it on an

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Speaker 1: actual dinosaur because it was hard to do. It was possible,

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Speaker 1: but you had to be a really skilled pilot, and

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Speaker 1: you were subjected to some massive uh stresses as you

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Speaker 1: did it. However, the course of nineteen sixty two, funding

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Speaker 1: was pulled from the Dinosaur project, forcing it to scale

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Speaker 1: back multiple times, and a night teen sixty three, the

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Speaker 1: government formally canceled the project, largely because Project Mercury and

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Speaker 1: then Jim and I were answering many of the questions

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Speaker 1: that Dinosaur was meant to explore, and the ballistics model

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Speaker 1: of returning astronauts safely to Earth was already proven to

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Speaker 1: be successful. So if you've already got a way to

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Speaker 1: get people back to Earth, why bother working on a

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Speaker 1: different way. Just focus on the way that works for

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Speaker 1: now and worry about the other one later. That seemed

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Speaker 1: to be the philosophy. I've got more to say about

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Speaker 1: early space planes, but first let's take another quick break

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Speaker 1: to thank our sponsor. One of the other designs that

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Speaker 1: I feel we need to talk about is the concept

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Speaker 1: of the lifting body. A lifting body aircraft has, as

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00:24:46,760 --> 00:24:50,520
Speaker 1: the name suggests, a body that's meant to generate lift

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00:24:50,720 --> 00:24:53,960
Speaker 1: when the aircraft is flying through the air. The body

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00:24:54,000 --> 00:24:56,919
Speaker 1: itself does this. This is normally the job of an

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00:24:56,920 --> 00:25:00,400
Speaker 1: aircraft's wings, but with a lifting body aircraft, the body

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00:25:00,440 --> 00:25:03,920
Speaker 1: itself is behaving as if it's a wing. Uh. This

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00:25:04,160 --> 00:25:06,639
Speaker 1: idea dated back to the late nineteen fifties. There was

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00:25:06,680 --> 00:25:10,200
Speaker 1: an egghead named Dr Alfred JA Eggers Jr. Who was

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00:25:10,280 --> 00:25:13,480
Speaker 1: at the time the assistant director of the Research and Development,

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00:25:13,600 --> 00:25:18,479
Speaker 1: Analysis and Planning Department at AIMES Aeronautical Laboratory. Leading up

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00:25:18,520 --> 00:25:21,040
Speaker 1: to Egger's proposal was a lot of work surrounding missile

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00:25:21,200 --> 00:25:23,879
Speaker 1: nose cones. The problem focused on ways to create a

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00:25:23,960 --> 00:25:28,320
Speaker 1: nose cone capable of surviving aeronautical heating due to re entry.

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00:25:28,800 --> 00:25:32,080
Speaker 1: There was an engineer named H. Julian Allen who concluded

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00:25:32,160 --> 00:25:36,159
Speaker 1: that if you made a blunt nose cone rather than

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00:25:36,240 --> 00:25:39,840
Speaker 1: a sharply tapered one, it would better hold up to

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00:25:40,200 --> 00:25:45,600
Speaker 1: the forces it would undergo, specifically the temperatures when undergoing reentry.

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Speaker 1: Eggers took this a step further. He found that if

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Speaker 1: he modified this blunted nose cone shape slightly, the new

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00:25:53,520 --> 00:25:57,280
Speaker 1: shape would actually produce aerodynamic lift if the body was

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00:25:57,359 --> 00:26:00,159
Speaker 1: flying through the air fast enough. This design would mean

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00:26:00,240 --> 00:26:02,120
Speaker 1: a spacecraft would be able to fly back to Earth

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00:26:02,320 --> 00:26:06,760
Speaker 1: rather than to just plummet to Earth ballistic style. Egger's

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00:26:06,800 --> 00:26:09,280
Speaker 1: and his peers created a design called the M two.

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00:26:09,560 --> 00:26:12,000
Speaker 1: So imagine that you have a cone shaped like an

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00:26:12,040 --> 00:26:14,440
Speaker 1: ice cream cone, and then imagine that it's on its

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00:26:14,520 --> 00:26:17,080
Speaker 1: side right, so you've got the wide end on one side,

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00:26:17,160 --> 00:26:19,280
Speaker 1: the point end on the other, round off the point

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00:26:19,440 --> 00:26:21,120
Speaker 1: end a little bit, so it's not two point, it's

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00:26:21,160 --> 00:26:23,840
Speaker 1: a little dull. And imagine that the top half of

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00:26:23,920 --> 00:26:27,160
Speaker 1: the cone is now flat. It is no no longer

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00:26:27,280 --> 00:26:29,560
Speaker 1: rounded at the top, it's flat, and the bottom half

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00:26:29,640 --> 00:26:32,840
Speaker 1: is still round. That's generally the shape they were working with.

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00:26:33,200 --> 00:26:35,760
Speaker 1: They added in some stabilization fins towards the back of

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00:26:35,800 --> 00:26:38,440
Speaker 1: the vehicle that poked up on either side, and you

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00:26:38,560 --> 00:26:41,600
Speaker 1: have essentially the M two F one lifting body vehicle.

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00:26:42,080 --> 00:26:44,720
Speaker 1: This vehicle was an unpowered test vehicle. It would be

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00:26:45,080 --> 00:26:51,080
Speaker 1: towed behind other aircraft to test its aerodynamic capability, and

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00:26:51,119 --> 00:26:54,960
Speaker 1: it was unmanned. Obviously, later vehicles were built on that

472
00:26:55,119 --> 00:26:58,679
Speaker 1: design and would incorporate an x l R eleven rocket engine,

473
00:26:58,720 --> 00:27:00,600
Speaker 1: which was the same kind that is used in the

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00:27:00,880 --> 00:27:05,679
Speaker 1: X one supersonic jet. Several lifting body aircraft designs followed.

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00:27:05,760 --> 00:27:09,120
Speaker 1: I think the X A is perhaps the weirdest one.

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00:27:09,359 --> 00:27:11,320
Speaker 1: You need to take a look at that aircraft. If

477
00:27:11,359 --> 00:27:13,840
Speaker 1: you can go to Google image search type of X

478
00:27:14,000 --> 00:27:16,720
Speaker 1: dash to four A, you're gonna see what looks like

479
00:27:16,760 --> 00:27:21,040
Speaker 1: a jet that's missing its wings. That's a lifting body aircraft. Now.

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00:27:21,080 --> 00:27:24,040
Speaker 1: The reason I even mentioned lifting body designs is that's

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00:27:24,080 --> 00:27:27,600
Speaker 1: what the Martin X twenty three Prime aircraft used, and

482
00:27:27,680 --> 00:27:30,119
Speaker 1: that was the next big space plane. This was an

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00:27:30,160 --> 00:27:33,639
Speaker 1: air Force project in the mid nineteen sixties. Prime itself

484
00:27:33,760 --> 00:27:37,880
Speaker 1: was an acronym. It stood for precision recovery including maneuvering entry,

485
00:27:38,320 --> 00:27:40,480
Speaker 1: and this was to test a lifting body design in

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00:27:40,600 --> 00:27:43,640
Speaker 1: relation to re entering the Earth's atmosphere and being able

487
00:27:43,720 --> 00:27:47,280
Speaker 1: to travel cross range up to eleven kilometers. That would

488
00:27:47,320 --> 00:27:49,639
Speaker 1: mean the craft would be able to steer along a

489
00:27:49,720 --> 00:27:53,000
Speaker 1: ballistics re entry path and land at a more precise location.

490
00:27:53,400 --> 00:27:56,280
Speaker 1: It was mostly made out of a titanium alloy, and

491
00:27:56,400 --> 00:28:00,480
Speaker 1: it weighed in at nearly eight two pounds or four legrams.

492
00:28:00,840 --> 00:28:05,119
Speaker 1: It was an unmanned vehicle and they held three successful

493
00:28:05,240 --> 00:28:09,120
Speaker 1: missions with the various ones. They had built five of them,

494
00:28:10,040 --> 00:28:13,120
Speaker 1: but after three flights, the Air Force canceled the rest

495
00:28:13,160 --> 00:28:16,160
Speaker 1: of the project, which left two X twenty three a's

496
00:28:16,320 --> 00:28:19,280
Speaker 1: completely unflown. Those were sent off to the United States

497
00:28:19,320 --> 00:28:23,000
Speaker 1: Air Force Museum at Wright Patterson Air Force Base. When

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00:28:23,080 --> 00:28:25,639
Speaker 1: Dinosaur got the AXE, the Air Force began to develop

499
00:28:25,680 --> 00:28:28,920
Speaker 1: plans for space planes under the same umbrella project that

500
00:28:29,040 --> 00:28:32,320
Speaker 1: the X twenty three A was under that was called Start.

501
00:28:32,920 --> 00:28:34,800
Speaker 1: After the X twenty three project got the AX in

502
00:28:34,880 --> 00:28:38,720
Speaker 1: nineteen sixty six, it would take nearly two decades before

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00:28:38,720 --> 00:28:42,200
Speaker 1: another space plane design would become a reality. That design

504
00:28:42,320 --> 00:28:45,600
Speaker 1: would be the Space Shuttle, which debuted in nineteen eight one.

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00:28:46,040 --> 00:28:48,080
Speaker 1: I've talked about the Space Shuttle recently, so this will

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00:28:48,160 --> 00:28:51,920
Speaker 1: just be a super quick overview version. First of all,

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00:28:52,160 --> 00:28:55,160
Speaker 1: the design of the Shuttle is similar to the earlier

508
00:28:55,240 --> 00:28:58,600
Speaker 1: lifting body spacecraft I've mentioned, though the Shuttle also had

509
00:28:58,640 --> 00:29:01,960
Speaker 1: a double delta wing configu duration. This particular shape is

510
00:29:02,000 --> 00:29:04,320
Speaker 1: efficient for hypersonic flight and was good at giving the

511
00:29:04,320 --> 00:29:08,200
Speaker 1: Shuttle a good lift to drag ratio, so it wasn't

512
00:29:08,360 --> 00:29:11,640
Speaker 1: a pure lifting body spacecraft. It also did have these

513
00:29:11,920 --> 00:29:15,880
Speaker 1: wings in an earlier design before they actually had to

514
00:29:15,960 --> 00:29:19,000
Speaker 1: commit to the final form of the Space Shuttle, it

515
00:29:19,120 --> 00:29:22,320
Speaker 1: was supposed to launch off the back of a larger aircraft.

516
00:29:22,840 --> 00:29:25,520
Speaker 1: The Shuttle would be kind of carried piggyback and would

517
00:29:25,600 --> 00:29:27,840
Speaker 1: launch from that aircraft once it reached a certain speed

518
00:29:27,880 --> 00:29:30,840
Speaker 1: and altitude, and then the Shuttle would make the rest

519
00:29:30,880 --> 00:29:33,560
Speaker 1: of the journey up to low Earth orbit, But budget

520
00:29:33,600 --> 00:29:36,560
Speaker 1: cuts at NASA forced engineers to switch to more conventional

521
00:29:36,680 --> 00:29:40,120
Speaker 1: rocket style launch vehicles. The Space Shuttle would ultimately launch

522
00:29:40,200 --> 00:29:43,360
Speaker 1: in a vertical position using a pair of enormous solid

523
00:29:43,520 --> 00:29:47,280
Speaker 1: rocket fuel boosters that would provide most of the thrust

524
00:29:47,400 --> 00:29:50,320
Speaker 1: at lift off. The three main engines on the shuttle

525
00:29:50,360 --> 00:29:53,440
Speaker 1: itself would provide the rest of the thrust at liftoff.

526
00:29:54,080 --> 00:29:56,600
Speaker 1: In Between the two solid rocket boosters was a huge

527
00:29:56,760 --> 00:29:59,920
Speaker 1: external fuel tank that held the liquid hydrogen and liquid

528
00:30:00,000 --> 00:30:02,479
Speaker 1: oxygen that would serve as the fuel for the main engines.

529
00:30:03,200 --> 00:30:06,400
Speaker 1: The shuttle would first jettison the two booster engines about

530
00:30:06,480 --> 00:30:09,320
Speaker 1: two minutes after a liftoff and then would later jettison

531
00:30:09,400 --> 00:30:12,560
Speaker 1: the huge external tank. Once the shuttle would reach a

532
00:30:12,680 --> 00:30:17,000
Speaker 1: velocity sufficient to insert into low Earth orbit, the booster

533
00:30:17,080 --> 00:30:20,680
Speaker 1: engines could be recovered and reused. The external tank was

534
00:30:20,720 --> 00:30:23,800
Speaker 1: not meant for reuse. At the conclusion of a Space

535
00:30:23,800 --> 00:30:26,880
Speaker 1: Shuttle mission, the shuttle would fire its orbital Maneuvering System

536
00:30:27,000 --> 00:30:30,520
Speaker 1: or o MS thrusters and leave orbit to re enter

537
00:30:30,600 --> 00:30:34,440
Speaker 1: Earth's atmosphere. The shuttle relied heavily on arrow braking, in

538
00:30:34,520 --> 00:30:37,960
Speaker 1: other words, too maneuver in such a way where the

539
00:30:38,080 --> 00:30:41,320
Speaker 1: air itself is slowing the descent of the shuttle through

540
00:30:41,360 --> 00:30:43,880
Speaker 1: the atmosphere, and it would do so until it reached

541
00:30:43,920 --> 00:30:46,400
Speaker 1: the lower atmosphere, where the shuttle could fly as a

542
00:30:46,480 --> 00:30:50,640
Speaker 1: powered glider. Between two thousand and eleven, the shuttles in

543
00:30:50,720 --> 00:30:54,800
Speaker 1: the Space Shuttle fleet collectively flew on on five missions.

544
00:30:55,280 --> 00:30:58,280
Speaker 1: Eight hundred thirty three people flew on a Space Shuttle mission,

545
00:30:58,360 --> 00:31:02,400
Speaker 1: with some going multiple times. Fourteen people lost their lives

546
00:31:02,440 --> 00:31:05,360
Speaker 1: and catastrophic accidents on the Space Shuttle program and the

547
00:31:05,520 --> 00:31:09,360
Speaker 1: Challenger and Columbia disasters. The Space Shuttle program proved the

548
00:31:09,520 --> 00:31:12,360
Speaker 1: utility of a space plane design a spacecraft that can

549
00:31:12,440 --> 00:31:15,920
Speaker 1: maneuver both inside the Earth's atmosphere and an orbit is

550
00:31:16,000 --> 00:31:19,320
Speaker 1: incredibly useful, particularly when you can fly the same spacecraft

551
00:31:19,440 --> 00:31:22,480
Speaker 1: multiple times. The end of the space Shuttle program in

552
00:31:22,520 --> 00:31:24,880
Speaker 1: two thousand eleven would not be the end of the

553
00:31:25,000 --> 00:31:27,600
Speaker 1: space plane era. In the next episode, I'm going to

554
00:31:27,680 --> 00:31:30,760
Speaker 1: talk about some of the other space plane designs, including

555
00:31:30,800 --> 00:31:33,400
Speaker 1: a super secret one that I covered in an older

556
00:31:33,440 --> 00:31:35,720
Speaker 1: episode of tech Stuff, And we'll learn about those and

557
00:31:35,840 --> 00:31:38,480
Speaker 1: other space planes, including a design from the United Kingdom.

558
00:31:38,640 --> 00:31:41,280
Speaker 1: So stay tuned for that. And if any of you

559
00:31:41,400 --> 00:31:44,160
Speaker 1: out there have suggestions for future episodes of tech Stuff.

560
00:31:44,160 --> 00:31:47,520
Speaker 1: Maybe it's a technology, a company, person in tech, anything

561
00:31:47,600 --> 00:31:49,480
Speaker 1: like that, let me know. Send me an email the

562
00:31:49,560 --> 00:31:53,280
Speaker 1: addresses tech stuff at how stuff works dot com, or

563
00:31:53,360 --> 00:31:55,600
Speaker 1: drop me a line on Facebook or Twitter. The handle

564
00:31:55,640 --> 00:31:58,280
Speaker 1: of both of those is tech Stuff H s W.

565
00:31:59,040 --> 00:32:01,280
Speaker 1: Don't forget to check. Got our merchandise over at t

566
00:32:01,520 --> 00:32:05,600
Speaker 1: public dot com slash text stuff. And finally, we've got

567
00:32:05,680 --> 00:32:08,720
Speaker 1: this Instagram account. You may have heard of it. Go

568
00:32:09,000 --> 00:32:11,280
Speaker 1: follow that, won't you, and I'll talk to you again

569
00:32:11,960 --> 00:32:20,240
Speaker 1: really soon for more on this and thousands of other topics.

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00:32:20,280 --> 00:32:21,840
Speaker 1: Because it how stuff works dot Com