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9 we have a go for main engine start

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five four three two one zero booster

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ignition and liftoff of Columbia a new

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decade of spaceflight begins six five

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four three two one ignition and liftoff

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of discovery and the Ulysses spacecraft

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that Space Shuttle Orbiter is rocketing

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into space but what is space how do we

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get there how do we stay there how do we

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get back to earth again well before we

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answer these questions let's look at

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some history of man Rockets this man

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Robert H Goddard is considered to be the

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father of modern rocketry he began

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testing Rockets as a young man and in

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1926 he launched the world's first

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liquid-fuel rocket he was also the first

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to propose using both solid and liquid

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why is that an important idea because

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that's how he boosts the Space Shuttle

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into orbit today it was in 1956 when a

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team of scientists engineers led by

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Bernhard von Braun launched the Jupiter

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C rocket this was the first time that we

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launched anything that went high enough

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to get into space two years later

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another Jupiter C traveled in space but

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this time had left a satellite up there

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to orbit the earth then in 1961 only

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months after the Soviet Union sent their

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first astronaut into space NASA launched

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the first American into space on board

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the Freedom say things were moving

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pretty fast first we had the mercury

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then Gemini and then just eight years

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after the first human would went into

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space a Saturn 5 rocket launched the

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Apollo spacecraft carrying the first

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today astronauts fly into space in a

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different vehicle the Space Shuttle

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Orbiter to give us enough energy to get

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into orbit we use special engines and

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propellants let's look at the shuttle a

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little differently this is what we call

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the stack sitting on the launch pad here

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in Florida let's look at it the way an

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the solid rocket boosters or SRBs burn a

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solid fuel the external tank where ET

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carries liquid oxygen and liquid

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hydrogen for the shuttles main engines

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this combination of solid and liquid

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propellants are very powerful we're

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launch we start the liquid main engines

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burst then the solid rocket boosters

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ignite and lift the whole stack off the

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pad downrange twenty two nautical miles

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the solid rocket boosters push the

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shuttle for about two minutes and up

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through the thickest part of the

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atmosphere then we separate from the

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Boosters the shuttles main engines

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continue to burn for another seven

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minutes

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pushing the orbiter fast enough to get

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and here's the result we're in space but

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we're in space are we in other words how

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far above the earth have we come let's

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use this picture to help explain here is

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the surface of the earth here would be

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the Earth's highest mountain Mount

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Everest which is about 6 miles high and

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right here would be where commercial

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airplanes fly about 6 to 7 miles above

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sea level the astronauts that went to

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the moon went 240 thousand miles above

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the earth and if we can put that on this

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picture to scale it would be 5000 feet

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this way well where does that leave us

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here in the Space Shuttle well right now

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in the Space Shuttle we are about right

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here 160 miles above the earth for

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example though the Space Shuttle can

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even go higher sts-31 that deployed the

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Hubble Space Telescope went all the way

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so what's it like up here well let's do

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a weather report from space well Tom I'm

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gonna have a little problem with that

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because there is no weather in space in

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order to have whether you have to have

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an atmosphere up here in the Space

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Shuttle we're well above the Earth's

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atmosphere so I can't give you a port on

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their weather but I can tell you what

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the conditions are going to be like

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outside today we can expect a scorching

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high of about 300 degrees Fahrenheit

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outside today in the Sun that's about

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150 degrees celcius down to a real

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freezing low of 150 degrees below zero

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which is a minus 100 degrees Celsius in

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the shade we can expect the relative

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humidity to be zero and our barometric

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pressure is also going to be zero now

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some of our viewers out there may be

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wondering why are these extreme

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conditions outside when we're only a

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hundred and sixty miles up above the

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Earth's surface and the living

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conditions down there are so nice well

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the reason is is down on the surface of

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the earth we have an atmosphere the

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atmosphere performed as a protective

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blanket for us when we live down on the

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surface of the earth here for example is

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a picture of what the earth looks like

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from a satellite 23,000 miles above the

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earth you can see that much of the

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surface of the earth is covered by

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clouds these clouds are the part of the

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atmosphere that you can see the visible

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part of the atmosphere the clouds were

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made up of water molecules those water

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molecules are what account for the

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relative humidity of our atmosphere the

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total weight of the atmosphere above a

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point on the surface of the earth is

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what it makes up for the barometric

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pressure now we don't have to worry

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about our climate here in the Space

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Shuttle when we're up here in space

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because we have an air-conditioner but

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we call our environmental control system

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on board this environmental control

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system will maintain our temperature a

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nice comfortable 77 degrees Fahrenheit

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which is about 25 degrees Celsius

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relative humidity will stay at about a

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constant 50% enter barometric pressure

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will be about 29.92 inches of mercury

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back to you Tom

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thanks Bruce as you can see the

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environment in space is very harsh so

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here in the orbiter we have to make the

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environment duplicate the environment

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and even though we're over 150 miles up

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in space here the pressure inside the

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space shuttle is almost the same as it

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is at sea level see it's fool this

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altimeter into reading almost zero well

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now we know where space is and what

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space is how do we stay here

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once we've arrived well 300 years ago an

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English scientist Sir Isaac Newton

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he began by showing a very high mountain

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the imaginary mountain was so high that

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he put a cannon on top of the mountain

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okay here's our imaginary mountain let's

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pretend that we can climb to the top of

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now if we throw one of these baseballs

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straight out from the top of the

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mountain when it goes straight out like

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a ball straight down like B or fall on a

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curved path while C is correct the

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baseball would fall on a curved path

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even on this tall mountain it still

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feels gravity this is because the ball

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has two motions acting on it at the same

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time it's trying to go straight out and

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it's also falling toward the earth the

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result is the baseball travels on a

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now let's throw another ball only this

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see it goes farther than the first if we

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throw another ball even faster than the

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last one that goes farther still so the

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faster we throw the balls the farther

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now we'll take our last ball and throw

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it as hard as we can just like the other

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balls it falls in a curved path but this

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one is moving so fast that it circles

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the earth we'll have to duck to missile

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it won't be safe to stand up for a while

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because unless something gets in the way

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the ball will continue to fall around

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the earth on a curved path we call this

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an orbit of course the Space Shuttle

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doesn't launch when the mountain but we

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still need a lot of speed to get into an

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so how fast do we need to be going to

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get into orbit well it's a space shuttle

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at a speedometer like the one in your

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car it would have to get all the way to

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17,500 miles per hour to make it into

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space

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so how fast is that well it took the

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early pioneers months to cross the

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it took the first transcontinental

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it would take about three days of

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driving round the clock to get across by

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car and it takes about five hours for

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the average airline that's like

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coast-to-coast but on board the shuttle

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we cross the country in ten minutes

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that's about five miles a second you see

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the Space Shuttle goes around the earth

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16 times every earth day that means we

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see a sunrise and a sunset once every 90

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minutes this could be a problem up here

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on the orbiter if I woke up when it was

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I'd be getting up and going to sleep

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every 45 minutes so instead we just plan

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another thing you should know is we just

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don't float around on the orbiter

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because there is no gravity we still

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feel Earth's gravity so why are we

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because we're falling let's say this

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string is gravity and let's say this

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Apple is like a spaceship orbiting the

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Earth you see its gravity in our speed

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that keeps us in orbit without gravity

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we would fly off into space and never

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come back

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here's another example when I dropped

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this Apple on earth it falls when I drop

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an apple here on the Space Shuttle it

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falls - it just doesn't look like it's

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and that's because we're all falling

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together the Apple me and the orbiter

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we're not falling towards the earth

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let's imagine that we can send Bruce

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the elevator is going to the top of a

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suddenly when he reaches the top the

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cable breaks in the elevator car with

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Bruce in it begins to fall what will

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happen inside the elevator well since

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he's falling and the elevator is falling

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the same rate he starts to float his

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body isn't pushing on the inside of the

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elevator anymore

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he has no weight he's weightless if he

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had an apple with him it would float too

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just like the one in the orbiter because

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Bruce the Apple and the elevator would

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all be falling together it would be a

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fun ride until he hit the bottom and

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that's why things float around up here

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even really big things because we're all

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falling on a curved path around the

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well now our work in space is done and

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it's time to go home so how do we do it

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well first we have to slow down let's go

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back to our imaginary Mountain here's

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our baseball orbiting the earth it's

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going around every 90 minutes - we know

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the other baseball's weren't able to get

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into orbit because we didn't throw them

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fast enough now to bring the baseball

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back for more of it

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all we have to do is slow it down just a

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those were maneuvering engines firing we

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here's what it looks like from outside

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the orbiter when they fire they slow us

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down just enough to make a safe descent

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just like the baseball we've got to slow

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down to get out of little bit we glide

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back to earth under computer control

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until our altitude is about fifty

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thousand feet then the commander and

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pilot take over and land our space

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space is great but a safe touchdown sure

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feels good after traveling two million

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miles in five days it's nice to be back

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home again so now we know that it takes

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a lot of power to push the orbiter

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through the atmosphere and into

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00:19:31,080 --> 00:19:27,220
low-earth orbit in space we have to go

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very fast to stay in space and we have

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to slow down just enough to allow

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Earth's gravity to pull us out of orbit

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when we want to return that's how we get

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into space how we stay there and how we

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00:19:51,390 --> 00:19:44,850
get back