WEBVTT
Kind: captions
Language: en

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- Five.

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"Three. Two. One. Pull up."

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- I'm experiencing 1.8gs
right now, which means I weigh

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about 1.8 times what I normally would.

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I've been instructed to keep my head
front and centre to avoid nausea.

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But all this is about to change

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because this is the
European Space Agency's zero-g flight.

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Those are students doing research.

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This is Neil, who's here for my safety.

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And we're about to go into freefall.

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Whoa!

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And here's the confusing thing.

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We are still going up right now.

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That camera is stabilised to
the actual horizon,

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and it's not until 10 seconds into
our 20 second parabola,

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into our manoeuvre, that we
clip the apex and start heading

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back down towards the ground.

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And here we go, 1.8gs.

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- In this special aircraft,
we divide the three axes.

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There is pitch, roll and thrust,

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and each pilot flies one axis.

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In every other aircraft, one pilot
flies the three axes and

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the other one manages the systems,
talks on the radio, and so on.

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To fly parabolas, we need to
fly only one axis by one pilot.

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We try to avoid any turbulence.

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Any turbulence is a nightmare for us.

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- The two control sticks,
just like any plane,

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are completely locked together,
so they always move at the same time.

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So one of the pilots is using

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effectively elastic bands
on either side of his stick

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so that he doesn't affect
the axis of the other pilot.

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One of them does the pitch,
the other one does the roll

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whilst trying not to upset the pitch.

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- In 1971, the Apollo 15 astronauts
tested something on the moon:

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The idea that all objects,
no matter their weight,

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fall at the same speed
if there's no air.

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They used a hammer and a feather,
and they landed at the same time.

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ASTRONAUT: "How about that?"

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- But the weirdest thing is that
if that astronaut had thrown that hammer,

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it still would have been in free fall

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from the moment it left his glove
to the moment it hit the ground.

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The only pull on it is from
the gravity of the moon.

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The maths work out the same

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no matter what speed or direction
it's going relative to us.

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That's what we just did here.

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If it sounds weird, sure,
but we just proved it.

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And we're about to prove it again.

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- Every five parabolas
or ten parabolas, we change

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to maintain the best accuracy
of the parabolas, especially

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on the pitch axis because
it's the most demanding flying technique.

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So after five or ten parabolas,
you are so tired and you

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have to go on to another
less demanding axis.

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PILOT: "3, 2, 1, pull up."

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- This parabolic manoeuvre
isn't the normal kind of thing

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that you do in an Airbus, and
the software in this plane

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hasn't been modified because to do so
would be a huge effort to re-qualify it.

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With the normal software,
you have the normal alarm

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saying, "This doesn't seem
like a very good idea, guys,"

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and one of the pilots that
isn't too busy on the other two axes

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is turning off the alarms
that we don't need to worry about

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and keeping track of the ones
we might need to worry about.

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PILOT: "Injection."

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- So those pilots are
keeping us on the exact path

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that an object would take
if you hurled it into the sky

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at hundreds of kilometres per hour
and there was no air.

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They're giving us this little protective bubble
of zero-g to fly around in.

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There is no terminal velocity here,
only the design limitations of the plane.

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And we're going to hit those pretty
soon, along with something else.

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Because when you're descending
this fast towards the ground,

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the Earth approaches pretty quickly.

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Thank you, Neil!

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If you're a Masters or PhD
student from an ESA member state,

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and you want to be
one of the people back there,

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then have a look at the
Fly Your Thesis program.

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The link is in the description.

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Thank you, Neil!

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I got it, I got it, we're good.

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And down.

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Oooph.