The Space Shuttle Richard Hammond's Engineering Connections


The Space Shuttle

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NASA's space shuttle is the most complex machine ever built,

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making it one of the world's most expensive vehicles.

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But then, it does travel 25 times faster than a speeding bullet,

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and it carries cargoes worth tens of millions of dollars.

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It's the world's first reusable spaceship.

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On each mission, it flies around four million miles.

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But no matter how clever the rocket scientists behind it are,

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this incredible feat of engineering wouldn't have been possible without...

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a church organ...

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..a German U-boat...

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..tram tracks...

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..a camera...

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It's mega!

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..and a cannonball.

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For NASA engineers, the Apollo moon missions were a tough act to follow.

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Even as man walked on the moon,

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the question was, "What would NASA do next?"

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The answer was the space shuttle.

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It launches into the Florida sky from the pads behind me.

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And as the world's first reusable space vehicle,

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it's made the final frontier just another destination.

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A fleet of five shuttles has blasted off

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from the Kennedy Space Centre more than 130 times.

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They've delivered well over 1,000 tonnes of cargo,

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including most of the International Space Station and the Hubble Telescope.

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Not bad for a delivery truck, albeit quite an expensive one.

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A new one will set you back a cool 1.7 billion.

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And taking it out for a spin costs about 450 million.

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But NASA designed the shuttle to reduce the cost of space exploration.

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So the shuttle is reusable,

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an ingenious jack of all trades, part plane, part rocket.

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I've come to look behind the scenes.

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Only astronauts or rocket engineers get close to the shuttle.

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This is the place where it starts. So next stop, space.

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But as they prepare for the shuttle's last ever launches,

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NASA has given me special access to see how it really works.

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You just picked it up!

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The shuttle is a combination of specialised parts put together

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for every trip and then rolled out to the launch pad - rather slowly.

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The shuttle isn't the white plane. That's the Orbiter,

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the bit which carries the astronauts to space.

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To get them there calls for two different rocket systems

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and a huge orange tank to store liquid fuel,

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all of which are jettisoned before reaching space.

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The whole assembly is the shuttle.

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The main rocket engines are at the rear of the Orbiter.

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They burn furiously during the shuttle's

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eight-and-a-half minute ascent into orbit.

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They are extremely powerful - 37 million horsepower, to be precise.

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And they propel the 2,000 tonne shuttle

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up to 650km above the Earth's surface.

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NASA has allowed me into the workshop where they overhaul the engines.

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-This our main engine shop.

-This is where it all happens?

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This is where we prepare all these motors after they've flown

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-to reinstall and get ready to go again.

-And these are they?

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'Mike Cosgrove is no ordinary grease monkey.

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'He's one of NASA's elite rocket scientists.'

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These are the next set of engines we're going to be installing.

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We're finishing up the processing on those,

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they've flown and gone through our shop here, and they've been completely refurbished

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and we're just putting the final touches.

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-So this'll be used next?

-This'll be used next.

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-This isn't a one-shot deal is it?

-No, this is a reusable engine.

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-Some of these motors have flown up to 25 times.

-Four million miles...

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-Per trip.

-This could be a hundred-million-mile job?

-Absolutely.

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Probably time for a service.

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These engines don't just travel enormous distances,

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they withstand extreme temperatures.

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Without any protection they would self-destruct.

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Temperatures exceed 3,300 degrees C or 6,000 degrees Fahrenheit.

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At 6,000 degrees, what would they do?

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-Normal metals would melt.

-Yeah. Gone.

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'And that is a problem.

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'Engines that melt will never do the job they're supposed to do.

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'It's like trying to make a kettle out of chocolate.'

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And we start with the very definition of uselessness -

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a chocolate kettle.

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Chocolate kettles, of course, famously useless

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because in order to heat water to be hot enough

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to make a decent cup of tea,

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well, on the way you'll melt the kettle.

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Chocolate is designed to melt in the mouth.

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In other words, at just below body temperature.

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So just to prove a point, I shall now try to make a lovely cup of tea.

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Yes, clearly already it is having trouble.

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Yep, its reputation is clearly deserved. Useless.

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Just as easily as my kettle, at shuttle operating temperatures,

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even metals would melt like chocolate.

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For the solution, NASA turned to a 19th-century machine

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that transformed church music.

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Church organs need a flow of air.

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Until a little over 100 years ago, it was pumped by hand.

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Right, to work, this is the lever, those are the bellows.

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I pump the lever. It puts air into the system.

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And there you have it, the original Hammond organ.

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Sorry, couldn't resist it.

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HITS WRONG NOTES

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Of course, inevitably, after a time, along came a machine to replace,

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well, me, the person who pumps the organ.

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It was an internal combustion engine, still in its infancy in the 1880s.

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The one first used to pump air into church organs

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also introduced an invention that would help NASA.

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And it would have been a machine very much like this one

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that replaced me driving the bellows to provide air for the organ.

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It's a single-cylinder internal combustion engine.

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But it had a problem, like all internal combustion engines,

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and the clue is in the name "internal combustion".

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It's an explosion going on inside it, here.

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And that makes the engine hot, dangerously hot.

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So it's jacketed with water. There's a water jacket around it.

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Another cylinder full of water to cool.

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Cold water is constantly circulating round the hot engine, removing the heat.

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This was the first cooling system for an internal combustion engine.

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It's a primitive version of what NASA uses on the shuttle.

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But while water can cool one of these engines,

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it's never going to do the job for NASA.

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At shuttle temperatures, most metals would get so hot,

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they wouldn't just melt, they would vaporise.

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So the rocket scientists had to take engine cooling to a whole new level.

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Luckily, NASA already had a great coolant on tap.

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Inside the giant orange tank is the fuel - super-cold liquid hydrogen.

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At minus 253 degrees Celsius, it is perfect for cooling engines.

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This is where you see the big fireball come out the backside.

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This is the bit we've all seen on the television...

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How are we going to cool this bad boy down?

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What we're going to do is take a tap off that liquid hydrogen

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that's being pumped around to the engine,

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and we're going to duct it down the side of the nozzle here, through these distribution tubes.

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It's going to fill up this manifold

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and then it's going flow back up through 1,080 tubes

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into the main combustion chamber and burn it.

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So the actual fuel that you're using is sent along these pipes here,

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-and I thought these were just marks.

-These are tubes.

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..which cools this down, protects it from the heat

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-of the engine...

-Correct.

-..and then it goes in and is burnt...

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-Correct.

-..which is one of the secrets to the incredible efficiency of this engine,

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-because you're using the fuel before you've burnt it.

-Correct.

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The reason shuttle engines don't melt is because of a principle

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first used in an engine like this to drive the bellows of a church organ.

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A cooling system - the removal of heat.

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The shuttle's fuel-cooling system is so efficient

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it keeps the engines at a cool 54 degrees Celsius.

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But can all this rocket science help me boil water with a chocolate kettle?

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To test NASA's system, I've built a radical new prototype.

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What we have here is something pretty special,

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because this is a chocolate kettle inspired by NASA.

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I've gone one better, in fact. This isn't just a chocolate kettle, it's a chocolate ice-cream kettle.

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Because that's what that is - chocolate ice cream.

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The challenge is to stop my ice cream from melting as the water heats up.

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Here's how it's working. This is the fuel for the burner down here, liquid propane.

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It's rushing along this narrow tube here, up here.

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Just like the shuttle, I'm using freezing-cold fuel to do the cooling for me.

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It then carries its way around here, down here, into the burner. That's the actual fuel I'm using.

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Because it's staying cool up here, despite this being full of now boiling water...

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..my ice cream is staying frozen.

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That's NASA, that is.

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100 degrees on the inside, below zero on the outside,

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but it still isn't a perfect kettle.

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One thing... I didn't design any way of pouring it out.

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That's refinement, I'll work on that.

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Just like my ice cream, the space shuttle main engines don't melt,

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even though they should be getting really, really hot.

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But even the staggering power produced by the most efficient engine in the world

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isn't enough on its own to get the shuttle into space.

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At liftoff, the shuttle is just too heavy.

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The engineers needed more power, but they had to limit the weight.

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It's a tricky thing to get right. To get more power, you need more engines and more fuel.

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More engines and more fuel means it's heavier.

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So the shuttle is fitted with these -

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boosters.

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These are solid rocket boosters or SRBs.

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They have a great power-to-weight ratio.

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And as the name suggests, the fuel they burn isn't liquid, it's solid.

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And it's very, very explosive.

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The height of a 15-storey building,

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these are the largest solid rocket boosters ever flown.

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When the fuel is lit, all those elements produce about 1,300 tonnes of thrust,

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about the same as 17,000 Formula One car engines.

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To get that amount of power, the fuel has to burn at incredible temperatures.

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The secret ingredient takes us back to tram tracks.

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In the 19th century, tram tracks were just bolted next to one another,

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and the gaps between them made for a bumpy ride.

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Then in the 1890s, German chemist Hans Goldschmidt

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invented a way to weld tracks together.

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Goldschmidt discovered that he could create an intense heat,

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by burning something you might not expect to burn at all -

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aluminium.

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First used in Essen, Germany, aluminium welding made for a much smoother ride

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and revolutionized tram lines across the world.

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It's the intense heat of burning aluminium that NASA exploits.

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Burning even a small amount can be hot enough not just to fuse steel, but to cut through it,

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which is why I have one of these.

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It's an aluminium lance, made out of aluminium foil as you'd find in the kitchen.

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Lots and lots of it rolled very tightly here into fine tubes,

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wrapped in yet more aluminium foil.

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This is something you shouldn't be trying at home in your kitchen.

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But you probably don't have the other ingredient you need - compressed oxygen.

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That's over there in the tanks.

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So oxygen flows from tanks, along my aluminium lance, up here.

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I ignite it, the aluminium burns.

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In theory, once lit, this should burn at...

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at least 2,500 degrees C.

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So it should be around about half as hot as the sun.

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But can my home-made lance make an impact on solid steel?

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Right, only one way to find out. Enough talking. Let's do it.

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Sometimes you can look at theories and numbers on paper,

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and sometimes you just need to see solid evidence.

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And I think that counts. Clearly, that was pretty hot.

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Burning aluminium provides enough

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heat to cut through steel and weld tram tracks together.

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And it's the vital ingredient for the shuttle's solid rocket boosters.

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Of course, the SRBs aren't just full of aluminium foil.

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There is other stuff in there as well,

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though you wouldn't want to wrap your sandwiches in it.

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Ammonium perchlorate -

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to provide oxygen for combustion -

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iron oxide, rust, to help it burn.

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EXPLOSION

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It's the powdered aluminium, though,

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that creates super-high temperatures.

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High temperatures turn the solid fuel into vast amounts of gas.

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And it's this gas that makes the rocket move.

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Because when a lot of gas is forced through a narrow nozzle,

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you get thrust.

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It's the same thing that happens when you let go of a balloon.

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The air inside is squeezed and shoots out this way.

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That's a push. There's an equal and opposite reaction

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which means a push this way.

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So the balloon...goes that way...

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..sorry!

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The challenge for NASA was to make a rocket that has as much thrust as possible

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right at the start,

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when the shuttle is at its heaviest.

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In an attempt to find out how they do that,

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I've asked rocket man David Beeton

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to help me build my very own Great British space fleet...

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of two.

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And, just like the shuttle's rocket boosters,

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we are using solid fuel made with powdered aluminium.

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-So this is the fuel...can I hold it?

-Yeah.

-Is it dangerous?

-No.

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'There is the same amount of fuel in each rocket,

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'which will burn along its entire length.

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'But the fuel with the hole down the middle should burn faster.

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'More fuel will be on fire at once,

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'so the rocket should fly faster right from the word go.'

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So because that's burning faster, the same load,

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because it's burning faster, the power is given more quickly.

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This will give a really good peak of power, and as it burns out,

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it will progressively increase the thrust.

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-Will that make a visible difference?

-Oh, yes.

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Can we test it?

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-We can.

-Can we have a race?

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I would think so.

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'So, other than the position of the ignition groove -

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'and the colour - these two rockets are identical.'

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If I drop this it's bad, isn't it?

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-It could be bad, yes.

-OK, fine.

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So, to get this right, this one has the faster burning charge.

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That has the faster burning motor. That's yours.

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Rocket science!

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That's OK.

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-Yes.

-Oh, yes.

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Job done.

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This is mine. Look at that one.

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EXPLOSION SOUND EFFECT

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We'll arm the system.

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Five, four,

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three, two, one,

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Go!

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In just ten seconds,

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the red rocket shoots 600 metres into the air.

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I think that was quite clear that the red one was a lot faster!

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The red rocket's fuel burns much faster,

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because more of the fuel is on fire at once.

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This means more hot gas is produced in a shorter time,

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which gives this rocket more thrust.

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The blue rocket eventually reaches roughly the same height,

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but it takes much longer to get there,

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even though it had a bit of a head start.

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-It was visibly quicker.

-It was.

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And that's just a faster burn.

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-That's just the fast burn.

-Same energy released,

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just more quickly.

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-Got to find them now, obviously.

-Yes.

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NASA's shuttle engineers need maximum thrust,

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so they go for a bigger, faster burn...like the red rocket.

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At launch, each booster is burning fuel at the unbelievable rate

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of five tonnes every second.

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They burn for about two minutes,

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then they are jettisoned.

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30 miles up, they fall away from the shuttle...

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..and back to earth.

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They crash-land into the Atlantic Ocean.

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Here - and this is the beauty of the system -

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NASA picks them up for refuelling back on dry land.

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So, thanks to a welding technique that smoothed out tram journeys,

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the thrust provided by the solid rocket boosters

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is enough to get the shuttle off the launch pad,

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and on a journey of its own...

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hundreds of miles into space.

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But the rockets are so powerful

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that they create a very dangerous problem of their own...

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..at lift off.

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The exhaust gases that generate thrust

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also generate phenomenal sound energy.

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This is so powerful, it can have fatal consequences.

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And this is the launch pad, where it all happens.

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During a launch, this place is just alive with energy, flames,

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searing gases, incredible amounts of noise.

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I'm underneath where the shuttle sits on the launch pad -

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this is the flame trench.

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I can only be here because the shuttle isn't in place right now.

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You certainly wouldn't want to be here when the countdown hits zero.

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And this trench was used in some Apollo missions as well.

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Just to think of the incredible amounts of energy these walls

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have taken over the years,

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it kind of boggles the mind.

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The firing rockets create a thunderous sound

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that slams into the bottom of this trench.

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This sound is energy.

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And systems engineer John Lorch knows how powerful this can be.

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Even way back, three miles away,

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you can feel that energy just popping in your chest,

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you know, and it's just amazing the amount of energy.

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Unchecked, all this energy would bounce off the ground,

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straight back up towards the shuttle.

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The vibrations would be so powerful, they would wreak havoc.

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On the first ever shuttle mission, they ripped heat-resistant tiles off the surface of the Orbiter.

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That time, the Orbiter returned to earth safely.

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But it could have burned up on re-entry.

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So the engineers needed to find a way

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to protect the shuttle from reflected energy.

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To do that, they had to absorb the sound energy that roared down here

0:23:450:23:49

and then bounced back up and hit the shuttle itself.

0:23:490:23:52

Back at the Hammond space centre, UK,

0:23:520:23:56

I can't replicate the shuttle's thunderous sound.

0:23:560:23:59

But I CAN give you a taste of its destructive power.

0:23:590:24:03

I'm going to build a wall here and then I'm going to knock it over

0:24:030:24:07

with a pulse just of air - phewf -

0:24:070:24:10

like that, only bigger.

0:24:100:24:13

A lot bigger.

0:24:130:24:15

I've just used the half one on the end, look, I've made a neat job of that.

0:24:180:24:22

'That's the wall built.'

0:24:230:24:26

'And over here is what I hope is going to blow it over -

0:24:260:24:30

'a vortex cannon.'

0:24:300:24:32

'First, we need to do a little test run.'

0:24:350:24:38

Three, two, one...

0:24:380:24:40

EXPLOSION

0:24:400:24:43

That is up there amongst the most amazing things I've ever seen!

0:24:520:24:56

EXPLOSION

0:24:560:24:59

An explosion in the base of the cannon

0:24:590:25:01

creates a single pulse of air, the shape of a doughnut.

0:25:010:25:05

Unlike sound, that moves in a wave,

0:25:050:25:08

the vortex flies through the air like a missile.

0:25:080:25:13

The vortex has a lot of energy but can it knock over my wall?

0:25:130:25:18

Jim's charging it with acetylene ready to make our explosion.

0:25:190:25:23

Don't overdo it, will you?

0:25:230:25:26

This is going to have to be one hefty puff of air.

0:25:260:25:30

Thank you very much.

0:25:330:25:34

If we're ready, everyone? In three, two, one...

0:25:340:25:37

EXPLOSION

0:25:370:25:39

It's just air.

0:25:430:25:45

In slow motion, we can see the vortex

0:25:520:25:56

as it travels through the air at over 200 mph.

0:25:560:25:59

And, as you can see, it creates a fair amount of destruction.

0:26:060:26:10

The shuttle's problem is much bigger.

0:26:260:26:28

Its exhaust gases jet out at about 2,500 mph,

0:26:300:26:35

producing vast amounts of sound energy as vibrations.

0:26:350:26:40

The engineers needed to find a way to protect the shuttle.

0:26:400:26:44

NASA turned to a system that connects the shuttle to U-Boats...

0:26:440:26:48

..via bubbles.

0:26:500:26:52

Acoustics expert, Tim Leighton,

0:26:520:26:55

from the university of Southampton shows me how.

0:26:550:26:58

What we have here is our very own mini sonar system.

0:26:590:27:03

A tube of water, a speaker at the bottom that plays cheeps of sound,

0:27:030:27:07

and at the top, an underwater microphone that will pick them up.

0:27:070:27:13

You can hear the sound cheeps and they are represented on screen.

0:27:130:27:19

I'm going to introduce bubbles in here,

0:27:190:27:22

because bubbles are really powerful at absorbing sound.

0:27:220:27:25

This is the key thing to watch?

0:27:250:27:27

That cheep is going to disappear. So here we go.

0:27:270:27:30

So you're literally just blowing bubbles in with this machine?

0:27:300:27:34

Oh, right, I can hear that.

0:27:340:27:36

But look at the screen. And it's gone.

0:27:360:27:40

The bubbles you see in the pipe are killing off that sound entirely.

0:27:410:27:46

We're still playing the sound cheeps through the water.

0:27:460:27:50

But even the smallest bubbles are stopping the microphone from picking them up.

0:27:500:27:55

There's nothing in there now.

0:27:550:27:57

-Are they enough to stop it?

-Yep.

0:27:570:28:00

But there's hardly any!

0:28:000:28:01

So these tiny, tiny, almost microscopic bubbles

0:28:010:28:05

are completely killing the sound on there.

0:28:050:28:07

The bubbles soak up the sound by getting hot.

0:28:090:28:13

So literally, the sound leaves here, which is just this wave,

0:28:150:28:18

this movement coming up through here.

0:28:180:28:21

When it encounters bubbles of air in the water,

0:28:210:28:23

the wave squashes the bubbles of air, that heats them up.

0:28:230:28:26

So the energy in the sound wave is turned into energy in heat.

0:28:260:28:29

So bubbles absorb sound.

0:28:310:28:33

But how does that help submarines?

0:28:330:28:36

World War II. The German U-Boat fleet is under attack.

0:28:370:28:41

The Germans want to make their subs untraceable

0:28:410:28:44

to the Allied destroyers and their sonar systems.

0:28:440:28:47

The Allied sonar worked by sending out sound cheeps from their ships

0:28:470:28:51

and then waiting for the echo to bounce back from a solid object.

0:28:510:28:55

This told them where German subs were.

0:28:550:28:57

If the Germans could absorb the sonar cheeps - no echo.

0:28:570:29:02

They would be invisible.

0:29:020:29:04

So they created rubber tiles to glue to the sides of their subs.

0:29:040:29:08

Tiles with bubbles in them.

0:29:100:29:12

This is a genuine World War II lining

0:29:130:29:19

from a German submarine.

0:29:190:29:23

And you see it's stuck onto the submarine this way.

0:29:230:29:25

This side is smooth. But this side has holes in, has voids in.

0:29:250:29:30

'The holes trap air, creating thousands of little bubbles.'

0:29:300:29:35

When a sonar ping comes and hits this,

0:29:350:29:37

these absorb the sound in the same way that those bubbles did.

0:29:370:29:42

So bubbles can make German U-Boats invisible.

0:29:420:29:46

But the shuttle isn't underwater, obviously,

0:29:460:29:50

and it has a bit more than just cheeps of sound to deal with.

0:29:500:29:54

To absorb the phenomenal noise of firing rocket engines,

0:29:540:30:01

NASA turned sound absorption on its head.

0:30:010:30:04

Instead of air in water, they put water in air.

0:30:040:30:10

Tim's got another tube with just air in it.

0:30:100:30:13

We're still sending cheeps of sound through it.

0:30:130:30:17

But this time, we're going to try to block them

0:30:170:30:21

with a mist of water droplets.

0:30:210:30:23

-This one into this one, yeah?

-Water into ice.

0:30:230:30:26

OK, so I pour that in there and it makes fog.

0:30:260:30:30

I can't see where I'm pouring. Hopefully it's into the tube.

0:30:300:30:33

That's going in, isn't it? I feel like a wizard.

0:30:330:30:37

And my spell seems to be working. Oh, look at that!

0:30:370:30:41

Absolutely knocked it right back.

0:30:410:30:44

So this is just fog, I'm not tipping the actual water in.

0:30:440:30:48

'The microscopic droplets of water in the air are vibrating,

0:30:480:30:51

'turning sound energy into heat.

0:30:510:30:54

'NASA protects the Orbiter in pretty much the same way.

0:30:540:31:00

'Though, needless to say, NASA's system is a bit more complicated.'

0:31:000:31:04

It looks like a warehouse.

0:31:040:31:06

It's actually the mobile launcher platform.

0:31:060:31:08

The shuttle assembly sits on top.

0:31:080:31:11

Those three, they're the Rainbirds.

0:31:110:31:13

And at peak flow, nine seconds after launch,

0:31:130:31:16

water hurtles through those at a rate of 900,000 gallons -

0:31:160:31:22

that's 3.5 million litres - a minute.

0:31:220:31:26

Releasing so much water, so quickly, through the Rainbirds

0:31:260:31:30

forms millions of water droplets suspended in air.

0:31:300:31:34

And it's these water drops that absorb the phenomenal sound energy.

0:31:340:31:40

The system for unleashing that amount of water

0:31:420:31:46

is unbelievably simple...

0:31:460:31:49

A water tower.

0:31:510:31:52

At heart, this is, essentially, a really big version

0:31:520:31:56

of the kind of water tank you'd see outside a town or city.

0:31:560:31:59

This is really just an elegant,

0:31:590:32:01

simple design to get that flow rate we need.

0:32:010:32:04

'When the valves open, more than a million litres of water plummets.

0:32:040:32:09

'It sprays beneath the rocket engines and absorbs the thunderous sound.

0:32:090:32:14

'So can water work against the vortex cannon?'

0:32:140:32:19

Time to see if what's good enough for the shuttle is good enough for my wall.

0:32:210:32:25

First, obviously, we've got to rebuild it.

0:32:250:32:27

Lovely!

0:32:340:32:36

'Next we need water. This is our Rainbird.

0:32:360:32:40

'The blast I'm about to fire has exactly the same power as before.'

0:32:420:32:46

'But this time, there's a curtain of water

0:32:490:32:52

'between the cannon and the blocks.'

0:32:520:32:56

OK. If we're ready, everybody?

0:32:560:32:59

In three, two, one...

0:32:590:33:01

EXPLOSION

0:33:010:33:03

EXPLOSION

0:33:060:33:07

In slow motion, you can see how the pulse of air

0:33:110:33:14

hits the water and loses energy.

0:33:140:33:17

EXPLOSION

0:33:220:33:24

Look at that!

0:33:260:33:28

I think we can safely say top marks, NASA, well done.

0:33:280:33:32

Their theory works, as I've just proved.

0:33:320:33:34

They'll be grateful. And it really did work.

0:33:340:33:38

By using billions of drops of water to disrupt the energy pulse,

0:33:400:33:45

the NASA engineers are able to protect their precious Orbiter and its payloads.

0:33:450:33:50

And it's all thanks to the power of the bubble.

0:33:500:33:54

Eight-and-a-half minutes after lift-off,

0:34:000:34:03

the Orbiter is more than 190 miles above Earth.

0:34:030:34:07

It's in space.

0:34:070:34:10

Only minutes later, the crew is getting ready to start its mission.

0:34:130:34:18

The Orbiter was designed, basically, to be a delivery van...

0:34:250:34:29

a very expensive, technologically advanced delivery van.

0:34:290:34:33

Its job is to deliver things into space.

0:34:330:34:35

So far it's put satellites, telescopes,

0:34:350:34:37

and most of the International Space Station up there.

0:34:370:34:40

But you can't just pop open the back and pull out your cargo.

0:34:420:34:46

Especially when it's a satellite or a chunk of space station.

0:34:460:34:51

Not the easiest objects to move. And expensive if you drop something.

0:34:510:34:57

So every shuttle cargo bay is armed with a helping hand.

0:34:570:35:00

Back on earth, NASA has a full scale replica of the shuttle's cargo bay.

0:35:000:35:08

Even if the astronauts could physically lift

0:35:080:35:11

and manhandle the cargo,

0:35:110:35:12

spacewalking is very dangerous.

0:35:120:35:15

So NASA turned to robots for help.

0:35:150:35:17

Specifically, a robot arm, called the Canadarm -

0:35:170:35:21

built by those famous space scientists, the Canadians.

0:35:210:35:25

They faced a real problem...

0:35:250:35:27

how do you grab hold of something in space,

0:35:270:35:30

without accidentally knocking it across the galaxy?

0:35:300:35:34

The answer was found in a camera lens.

0:35:340:35:38

Camera lenses, just like our eyes, have irises in them

0:35:410:35:44

that control the amount of light allowed through the lens.

0:35:440:35:48

In a camera lens, they're made up of interlocking metal plates,

0:35:480:35:52

which, when twisted, change the size of the aperture in the middle.

0:35:520:35:57

But how did this end up on the Canadarm,

0:35:570:36:01

on board the Space Shuttle?

0:36:010:36:04

The first designs for the Canadarm gripped objects, much like a hand.

0:36:040:36:09

But engineers quickly realised there was a fundamental problem.

0:36:090:36:15

The smallest of accidental nudges could send any cargo hurtling off.

0:36:150:36:20

There is no air resistance in space, so once something starts moving,

0:36:200:36:24

it doesn't stop.

0:36:240:36:26

For some reason, NASA wouldn't let me play with their 100 million arm,

0:36:280:36:33

in orbit.

0:36:330:36:35

So to find out just how big a problem this really is,

0:36:350:36:39

I've asked Neil Billingham to introduce me to one of his robots.

0:36:390:36:44

So I move it like that? So that's forward.

0:36:460:36:50

Ooh, it's faintly spooky.

0:36:500:36:53

'What I'm doing is pretty much what shuttle astronauts

0:36:530:36:56

'have to do in space.'

0:36:560:36:57

'And I'm beginning to get the hang of it.'

0:37:000:37:03

See if I can scratch my nose with it - it's annoying me.

0:37:070:37:11

That's the best thing I've ever played with. It's mega!

0:37:150:37:18

'On Earth, the claw on the end can open and close,

0:37:200:37:24

'making it a perfect tool for grabbing things.'

0:37:240:37:27

That closes the gripper, the other one opens it.

0:37:270:37:30

Glad I didn't do that when my nose was in it!

0:37:300:37:33

This claw arrangement, clearly a very useful,

0:37:330:37:35

multipurpose device here on Earth.

0:37:350:37:39

How would it work in space? Well, we can find out,

0:37:390:37:41

because I've constructed here my very own satellite.

0:37:410:37:45

The helium balloon behaves like a weightless satellite in space.

0:37:450:37:51

So it's very hard to grab hold of.

0:37:510:37:55

And I'm not just making this up.

0:37:550:37:57

Peter Stibrany is a Canadarm expert.

0:37:570:37:59

OK, it's in position. I'm going to go for a grip.

0:37:590:38:02

Well, that's not worked at all.

0:38:030:38:05

That's also given it a shove.

0:38:050:38:06

I presume, in space, that would be really bad news.

0:38:060:38:09

Certainly you could push your target away from you.

0:38:090:38:14

And if we were in space, that would have just kept going.

0:38:140:38:16

'One wrong move on the real, 15 metre-long arm,

0:38:160:38:19

'and I could send millions of dollars worth of satellite racing out of reach.

0:38:190:38:24

'Somebody would be cross.'

0:38:240:38:27

'NASA needed a new way to grab hold of things in space.

0:38:270:38:32

'One with 100% accuracy.

0:38:320:38:35

'Then an engineer working on the robot arm had a Eureka moment.

0:38:350:38:41

'A keen photographer, his inspiration was the camera iris.'

0:38:410:38:44

'And I have a mini version of what he helped design to go into space.

0:38:460:38:51

'Like a camera iris, it rotates, but instead of interlocking plates,

0:38:510:38:56

'it has three wires that close in.'

0:38:560:39:00

And almost straight away, I've captured what I'm after.

0:39:000:39:03

And I reckon...

0:39:030:39:07

that's my space telescope caught! It took me seconds to do it.

0:39:070:39:11

Why is it so much easier with that than an ordinary grab?

0:39:110:39:16

The initial volume that it can grab is very large.

0:39:160:39:20

So just make sure your target is somewhere in there,

0:39:200:39:23

you don't have a lot of alignment.

0:39:230:39:25

Once locked tight, astronauts can easily manoeuvre a chosen satellite.

0:39:250:39:31

Thanks to a simple camera iris,

0:39:320:39:35

the Canadarm is now a vital part of all shuttle missions.

0:39:350:39:39

But once the mission is complete,

0:39:430:39:46

there is still the pressing problem of getting back to Earth...

0:39:460:39:50

in one piece.

0:39:500:39:53

The return journey is one of the most dangerous parts of any shuttle mission.

0:39:580:40:04

And it can be fatal, as every astronaut is all too aware.

0:40:040:40:09

In 2003, the Orbiter Columbia burned up

0:40:130:40:18

as it re-entered Earth's atmosphere,

0:40:180:40:20

killing all seven crew members.

0:40:200:40:22

The problem is the incredible speed.

0:40:280:40:30

At re-entry the Orbiter is travelling at 17,000 mph.

0:40:300:40:37

High speeds in space are not a problem, there's no atmosphere.

0:40:420:40:46

But start hitting trillions of tiny particles in the upper atmosphere and things change.

0:40:460:40:51

Hitting all those particles creates friction. A lot of friction.

0:40:510:40:55

And that generates heat.

0:40:550:40:57

Aeroplanes, missiles and bullets are usually streamlined,

0:40:570:41:00

so they can slip through the air

0:41:000:41:02

creating as little friction as possible.

0:41:020:41:04

Early scientists thought that would work for rockets.

0:41:040:41:07

But in the 1950s, space scientist Harvey Allen,

0:41:080:41:13

realised that rocket speeds come with their own problem.

0:41:130:41:17

Travel at five times the speed of sound and above

0:41:170:41:20

and the friction is too intense.

0:41:200:41:22

No matter how sleek the design,

0:41:220:41:24

no known substance could survive the heat for long.

0:41:240:41:29

Allen's solution was, at first hearing, pretty radical.

0:41:290:41:33

Rather than make the nose of anything needing to re-enter the atmosphere sharp and sleek,

0:41:330:41:39

he said to make it blunt, deliberately un-aerodynamic.

0:41:390:41:44

And that's why the Orbiter's blunt nose can be connected

0:41:440:41:49

back to a very un-aerodynamic flying object - the cannonball.

0:41:490:41:54

We now know a round cannonball is not the perfect flying shape.

0:41:540:41:58

But its ultimate aim is not to fly,

0:41:580:42:00

it's to smash as much of something as possible.

0:42:000:42:03

But how does smashing into air help the Orbiter on re-entry?

0:42:070:42:12

This is the University of Manchester.

0:42:140:42:18

But it's a very specific little corner of the University

0:42:180:42:22

because these machines are dedicated to serving

0:42:220:42:26

another very, very special machine through there.

0:42:260:42:29

It's a wind tunnel.

0:42:290:42:30

But these winds will be travelling at hypersonic speeds. Up to Mach 6.

0:42:300:42:35

That's six times the speed of sound.

0:42:350:42:39

Obviously, that kind of performance

0:42:390:42:41

involves the release and control of stupendous amounts of energy,

0:42:410:42:46

which is why the actual wind tunnel itself

0:42:460:42:49

isn't as big as some of you might have been used to.

0:42:490:42:52

So to go inside it, I have one mini Orbiter with a pointy nose,

0:42:520:42:58

and one with a blunt nose.

0:42:580:43:00

Kostas Kontis is head of aerospace research.

0:43:000:43:04

First, I want to see exactly why a pointy-nosed design

0:43:040:43:09

is such a bad idea for the Orbiter.

0:43:090:43:11

I guess it's got to be fairly firmly fixed.

0:43:110:43:14

Of course. You don't want them to fly around. It's quite dangerous.

0:43:140:43:18

What if this tunnel goes off while my hand's in there?

0:43:180:43:21

Probably you would lose your hand.

0:43:210:43:23

It would just be blown away.

0:43:230:43:25

I don't want that to happen. Let's get this done quickly.

0:43:250:43:28

'At these speeds, you can only see what's happening

0:43:300:43:34

'with an elaborate system of mirrors, lenses,

0:43:340:43:37

'and high-speed photography.'

0:43:370:43:39

So if we can switch off the lights, please.

0:43:420:43:46

-There's a lot of energy about to be released.

-That's right, yes.

0:43:460:43:50

'A 3.700 mph jet of air, to be precise.'

0:43:500:43:56

Fire!

0:43:560:43:57

LOUD WHIRRING

0:43:570:44:00

That was strangely frightening.

0:44:060:44:08

Right let's get that image up and have a look.

0:44:080:44:11

So this is with the pointed nose,

0:44:110:44:13

and with this system you can actually see the shockwave.

0:44:130:44:16

'The air around the nose is compressed so much

0:44:160:44:20

'that it forms super-heated shockwaves.'

0:44:200:44:24

It actually hits the wings. So that's the tricky part.

0:44:240:44:29

Because it's quite dangerous, the temperatures are very high.

0:44:290:44:33

So this shockwave punches through the air, goes over the wings.

0:44:330:44:37

And I thought that was good, it's making a tiny hole, it's sleek.

0:44:370:44:40

But where that line hits the wing,

0:44:400:44:42

there's a lot of energy being deposited right there.

0:44:420:44:46

'The wing tips are exposed to high-speed air, so lots of friction.

0:44:460:44:51

'And at Orbiter speeds,

0:44:510:44:53

'the shockwave itself reaches thousands of degrees Celsius.'

0:44:530:44:57

-So, because of the shape of its nose, it can tear its own wings off.

-Exactly, yes.

0:44:570:45:02

And the wings are rather important.

0:45:020:45:05

Up until re-entry, the shuttle has been a rocket.

0:45:050:45:09

But now, it's a plane that has to glide back to earth.

0:45:090:45:14

So counter to what we would expect, the pointy shape doesn't work.

0:45:140:45:19

So how will the blunt nose fare?

0:45:190:45:22

Fire!

0:45:250:45:27

-OK, that's it.

-OK, lights up.

0:45:330:45:36

Right, moment of truth. This is where we see, hopefully, some difference. Go on then.

0:45:360:45:41

-OK. Let's pres the button.

-OK.

0:45:410:45:44

Whoa! Well, that couldn't be clearer, could it?

0:45:440:45:47

'With a blunt nose, the shockwave misses the wings completely,

0:45:470:45:52

'and deflects high-speed air away from the Orbiter's wings.

0:45:520:45:56

'So no friction.'

0:45:560:45:59

It's completely counterintuitive. I just would not guess that,

0:45:590:46:02

if I was to design something to re-enter the atmosphere.

0:46:020:46:05

I would immediately think, well, pointed is best.

0:46:050:46:08

That's against what your instinct tells you.

0:46:080:46:10

So, thanks to a cannonball, blunt is best for re-entry.

0:46:100:46:15

But, as is seen in this footage from the Orbiter's cockpit,

0:46:150:46:19

The shockwave around the craft glows intensely.

0:46:190:46:23

At Mach 25, it's superheated to 5,500 degrees C.

0:46:230:46:28

It might not touch the Orbiter, but as you can imagine,

0:46:280:46:32

it still makes it pretty warm.

0:46:320:46:35

So, at NASA's Kennedy Space Centre, scientist Martin Wilson is in charge

0:46:350:46:40

of producing heat-resistant tiles to protect the space vehicle.

0:46:400:46:44

Heat. It's very hot.

0:46:450:46:48

So this, essentially, is a kiln?

0:46:480:46:50

Yes, this is one of the kilns that we use

0:46:500:46:52

in the heat treatments of the tiles during manufacture.

0:46:520:46:57

And what sort of temperature is it in there?

0:46:570:46:59

The temperature inside the kiln is 2,200 degrees, 1,160 Centigrade.

0:46:590:47:04

These are actually the materials from which the tiles are made.

0:47:040:47:08

-You just picked it up!

-It's pure silica.

0:47:080:47:10

-But it's just come out of there. Seconds ago.

-Still very, very hot.

0:47:100:47:14

Have you got special hands? Can I do that?

0:47:140:47:16

No, you can do that. Touch it only by the corners.

0:47:160:47:19

That's just come out of that kiln. That's astonishing.

0:47:190:47:23

You can still see the energy bouncing around inside it.

0:47:230:47:26

'Silica cools down very fast at its edges.

0:47:260:47:29

'But because the tiles are effectively a silica foam,

0:47:290:47:35

'they are also full of air.

0:47:350:47:38

'This makes them great insulators.

0:47:380:47:41

'So, thanks to these heat-resistant tiles and cannonballs,

0:47:410:47:45

'the Orbiter completes re-entry, and glides in for landing.

0:47:450:47:50

'It touches down at just 220 mph.'

0:47:500:47:53

So after a journey of some four million miles,

0:47:550:47:59

at about 23 times the speed of sound, the Orbiter,

0:47:590:48:02

the final part of the Shuttle,

0:48:020:48:05

is safely here back on Earth.

0:48:050:48:07

Over three decades, NASA's shuttle fleet has travelled

0:48:070:48:13

over 500 million miles.

0:48:130:48:14

It's taken mankind into space to orbit our world,

0:48:140:48:20

and push the frontiers of our knowledge.

0:48:200:48:23

It owes its engineering DNA to...

0:48:230:48:26

a church organ,

0:48:260:48:28

a German U-boat,

0:48:280:48:30

tram tracks, a camera

0:48:300:48:32

and a cannonball.

0:48:320:48:35

Subtitles by Red Bee Media Ltd

0:48:500:48:53

E-mail [email protected]

0:48:530:48:57

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