The Next Frontier Royal Institution Christmas Lectures

INDISTINCT LIVELY CHATTER

'Glad to see you.'

This was where the adventure starts for me.

1975, my parents take me downstairs to watch

the Apollo-Soyuz Test Project -

the final mission of Project Apollo and its famous first handshake

between Russian and American astronauts.

40 years later and we see the fruits of that collaboration,

up there on the International Space Station, Tim Peake's mission.

That platform is a platform for peaceful collaboration in science

and exploration, and it is the jumping off point for new adventures.

This lecture is all about the next frontier and that frontier...

is your frontier.

APPLAUSE

Thank you and welcome to the 2015 Christmas Lectures.

I'm Dr Kevin Fong, I'm a medical doctor, and I used to work with Nasa,

helping them protect astronauts

as they went about the business of exploring space.

This is the final lecture in our series

and in this lecture we have our sights firmly fixed on the future

and what it's going to take with the edge of all that science,

technology and engineering has to offer us to protect astronauts

as they go about trying to go further and deeper into space.

But first, let's go to Tim Peake and the ISS to look at

the unexpectedly dramatic start

to Tim's first few days aboard the station.

Up on the screen just there you can see Tim, who's reading a checklist.

On the other side of that door are his crewmates, Tim Kopra

and Scott Kelly, who are in the airlock in their suits,

getting ready to go out the door on a spacewalk - which is pretty much

the most dangerous thing astronauts ever have to do.

INDISTINCT TECHNICAL CHATTER

Now, we'll be seeing more of how that spacewalk turned out

later on in this lecture,

but first, let's have a look at how much of space we've already visited.

Let's make a constellation of everywhere we've been to explore.

Now, these are our lights of exploration

and this is the first light in 1957.

Sputnik.

You're going to be Sputnik for me - who's going to be Sputnik? Well done.

All right, so Sputnik in '57.

And then, in '61, the first human, Yuri Gagarin,

goes into low Earth orbit.

And by the end of that decade, famously, we're on the moon.

Six crews, 12 people to the surface of the moon,

and in that same decade we go to our neighbours -

Mariner 4 in 1964

takes the first photographs of the Red Planet of Mars.

And then we go to our nearest neighbour, to Venus.

And then we master the art of the slingshot

and we're going to Jupiter, and then off to Saturn and their moons

and suddenly nothing in the solar system is beyond our reach.

We're in to Mercury, we're out to Pluto

and now we stand with Voyager,

the most distant man-made object from the Earth

at 50 billion miles from Earth.

And this is the constellation of exploration in space today.

But wait.

Where have we been with humans?

Everyone who doesn't have a human mission, turn off your lights now.

And what are we left with? We're left with low Earth orbits and the moon.

And there's a reason for that.

Rocket science is hard enough before you start trying to include people

as parts of the payload.

But with everything that we've learnt

in the history of human space exploration,

we're ready to go again.

And particularly with the lessons we've learnt from the mission

that Tim Peake is now involved in aboard the ISS,

we are going back to the moon. We're going to go off to Mars and perhaps

even more exotic destinations, and this time we're going with people.

But where might we go?

We could start with the moon. There is unfinished business there.

And to explain what that business might be and why humans

should go there, I'd like to welcome our very first guest -

planetary scientist Dr Katie Joy.

APPLAUSE

Katie, I'm more of a Mars man myself

so convince me that we need to send humans back to the moon.

Cos we've been there. We've been there six times - 12 people.

We have. We might have been there, but we've certainly not done that.

So, we've sampled the near side of the moon from just six places.

All that moon rock came back, it's located over at Nasa.

But scientists around the world are still studying it to try

and understand the moon's past and also to understand the moon's place

in the solar system. So, we need to go back and we need to get more

to really understand it. There's a lot more still to do.

But really, there needs to be something really, really valuable

up there to make it worth going. What is it that we would learn

from the moon that would be so vital to us here on Earth?

So, we can actually study the moon to understand our own origins,

so the origin of Earth itself.

But what's really exciting is the idea there may actually be

early Earth material on the moon.

So, samples, geological rocks from when life first started on Earth.

These are not well-preserved on Earth because we have active

plate tectonics, oceans, atmospheres

that have destroyed these ancient rocks. But who knows?

Big asteroids and comets were striking the Earth

and they may be able to chip little bits off.

That can travel through space

and maybe they're just landing on the moon, ready for us to find.

I think we're going to need a volunteer.

Who would like to volunteer to help us explain this?

All right, let's go up here and duck under there and we'll have...you.

Yeah, come on.

-Come and stand here and face the front. What's your name?

-Joseph.

Joseph, you're going to help me, you're going to need these.

All right, Katie, I've no idea what we're going to do here, but tell me.

OK, we're going to pretend this box is the early Earth,

and this is examples of ancient rock sitting on the early Earth.

We're going to pretend that these guys - here we go,

we have some pretend asteroids. They look like iron meteorites to me.

And we're going to hurl them at the Earth's surface.

-So, that's a meteorite.

-Goggles on, this sounds sort of dangerous.

We're going to try throwing some into the box and the objective

is to kick some oil out and have it try and hit the moon.

Surface of the Earth, moon, you've got to get some rocks onto the moon

-to convince me we need to go there. Go for it.

-OK.

Oh, Alex, you're going to need some goggles for this one, cos this is

overwhelmingly dangerous, throwing stuff into that.

OK, here we go. Joseph, give it your best shot.

OK. We're not doing a grand job.

We're sort of throwing at speeds of, you know,

-a couple of metres a second.

-OK.

-We need to ramp it up a little bit.

I told him he needed goggles, I look a bit stupid now, don't I? Um...

Why isn't this working?

Why can't you get the rocks off the Earth onto the moon here?

So, when asteroids and comets hit the Earth, they're travelling at

hypervelocity impact, so we need to get the material up about

11 kilometres a second being spooled off.

I think I have a hypervelocity impact simulator, specially built.

This is our hypervelocity impact simulator.

It's very hi-tech and, Joseph, you're going to help me fire it off.

OK, Alex, you ready for this? OK.

Our asteroid or comet is travelling closer and closer to the Earth,

it's nearly getting ready to go.

We're getting to the right sort of speeds.

Let's count in. Three, two, one. Go!

Joseph, come round here.

Sorry about that, Alex. You need a new set of clothes.

So, there's rock all over the moon all of a sudden.

And that's, I guess, what we're looking for. Joseph, thank you

very much for helping us. Ladies and gentlemen, Joseph. Thank you.

Now, Katie, you have brought some of the moon with you tonight.

I have some small chips of Apollo samples that were brought back

by the astronauts, and we actually have a beautiful thin section

of lunar rock under the microscope that you can see here.

So, this amazing sample, it looks like a stained-glass window

when we shine light through it. And this is actually a lava flow.

We've got it on the screen.

You can guys can see some spectacular colours.

All these different colours represent different minerals

and these formed in a lava flow that erupted from a volcano

about 3.2 billion years ago. Just amazing.

And this is a piece of rock brought back by the Apollo astronauts

-nearly 50 years ago now.

-Yeah.

And you've studied it as part of your PHD, didn't you?

Yeah, we study rocks like this to understand the moon's volcanic past.

This one came from the Apollo 12 mission,

so the second mission that went to the moon.

But rocks like these may be really good traps for preserving

some of these amazing archives of meteorites,

and maybe Earth samples that have been delivered to the lunar surface.

But they're incredibly beautiful to look at as well.

Absolutely beautiful.

It's amazing that so long after Project Apollo

they're still teaching us valuable lessons.

Sounds like a job for a planetary geologist like you on the moon.

Would you go to the moon?

So, we did get one geologist on the moon on the last mission

and I would love to be a future geologist.

I might try applying again next time. We'll see what happens.

-Yeah, you applied to be an astronaut.

-I did. We'll keep trying.

Maybe somebody else in this room can have that opportunity to do it.

Katie, fantastic to see you.

You have convinced me we've got to send people back to the moon.

-Thank you very much.

-Katie Joy.

Thank you.

It is incredible, really, that we were able to go to the moon.

Not just because we left behind on Earth, when we went to the moon,

everything we take for granted in terms of life support

here on Earth, but because we also left behind our protection

from radiation, the protection we get from the Earth's magnetic field.

Now, Tim Peake is on the space station,

very carefully monitoring his own levels of radiation

using a clever detector called the Timepix detector.

And to explain a little bit more to you about this,

I am going to need a volunteer.

All right, let's go on a bit of a space mission.

Let's have you.

-What's your name?

-Celeste.

-Celeste, put some gloves on.

We've got some bizarre stuff to show you here.

Celeste, have you ever seen one of these things before?

-Do you know what this is?

-No.

-This is a Geiger tube.

Anyone ever seen one of these before?

Yeah, yeah, yeah. OK, and it measures...?

Radiation. OK, so we're going to turn it on.

BEEP Oh! There you go.

Celeste, point that at the audience, see how radioactive they are.

This is a Geiger tube, it tells us how radioactive things are.

The more radioactive they are, the more clicks you get off of this.

It measures the ionisation as radiation comes in the front.

No? No radioactive people? How about over there?

No? OK, let's point that up to the sky. No real radiation.

Hmm.

That's because we're under a blanket of atmosphere

and the Earth's magnetic field,

so to show you some radiation, we've had to find something radioactive.

And here at the Royal Institution, Charlotte, our curator,

has some very exotic sources of radiation.

Point it at this book.

GEIGER TUBE CLICKS LOUDLY Charlotte, what is this book?

This is notebook from William Crookes from 1903.

I remember he's the bloke who made the very first medical -

-this is not good is it? - medical X-ray tubes.

-Yes.

GEIGER TUBE CLICKS LOUDLY That sounds very radioactive.

I might take that.

All right, now this book, this is the page where he was talking about

messing around with some radium salts?

-Yes.

-That's radioactive stuff.

I think he was messing around when he was writing this page.

-Which is the worst bit on this book?

-Down the crease.

-OK.

GEIGER TUBE CLICKS LOUDLY

LOUD BEEP Oh!

LAUGHTER

That's not good at all.

CLICKING AND BEEPING

OK.

It's very, very, very radioactive.

-Where do you keep this book, Charlotte?

-In the RI Archives.

-Yes.

-In a metal box.

-OK.

Now, it's OK so long as we don't eat or lick the book. OK?

So, do not eat or lick the book.

Now, all that does is tell us how much radiation, Celeste.

So, to do something rather more interesting,

we'd like to know the sorts of radiation, how many particles.

We're going to use the detector that is on Tim Peake's mission.

This is the Timepix detector. You're going to help me start it

so you're going to go round the front there and let's see

how Mr Crookes' book does.

OK, I'm going to take off the cover now over that page.

So, every spot is a particle.

The bigger the spot, the higher the energy. Here we go.

Let's have a look

at what we see.

The book has suddenly...

Oh, here we go.

Here we go.

And so all of those dots that you can see there

are all particles of radiation or photons

of energy coming through that detector.

I don't think you can see it quite as well as we can see it here

but, Celeste, that's a lot of particles, isn't it?

Charlotte, I don't want to stand near this book any more

so I think you should take it away.

Celeste, I think your mum would be really happy if I sent you back

to your seat as well. Thank you very much, Celeste.

So, lesson one is don't eat radioactive things,

but we have some data from the space station,

from the detectors that Tim Peake is using, and this is it.

And to help us understand what we're looking at, I'd like to welcome

my guest, solar physicist Professor Lucie Green.

APPLAUSE

Lucie, what is that? It looks very worrying.

That detector tells us not just how much radiation, but the type,

so what type of radiation is doing that?

So, this detector's able to pick up electrons,

protons and also heavy atomic nuclei that come streaking in

from all over our galaxy, travelling at almost the speed of light.

Sounds slightly nasty.

We don't have to worry about those so much here on Earth.

You've got something here to explain that to us.

That's right, so this is a set-up called a Planeterrella

and it's a really nice way to demonstrate both the fact

that the Earth has a magnetic field

which guides electrically charged particles and also the effect

of electrically charged particles on the Earth's atmosphere.

And what's happening in here is that electrons, charged particles,

are being accelerated through an invisible magnetic field,

and you can see that's around that small sphere, glowing lights.

And that's equivalent to the Northern Lights

-and the Southern Lights, the aurora.

-It's very, very beautiful even here,

but there is a more beautiful way of seeing this

and that's to be in space, and I think we've got some video

of the Northern Lights as seen from space.

Look at that.

That green glow in the top, that's the Northern Lights,

and this is from the space station looking down.

It's such a fantastic view.

The astronauts have the best view of the Northern Lights.

I'm so envious of what they get to see.

You see the thin atmosphere, the green glowing oxygen.

But for us, it's incredibly important, cos it acts as a blanket

to block out the effects of those galactic charged particles

that we saw earlier on.

So, we can protect ourselves from some of the most harmful radiation

by sitting inside our blanket of magnetic field,

so are we all right to keep carrying on exploring?

Well, there are difficulties that we have to overcome,

really severe difficulties. So, we've talked about particles

coming from the galaxy and the fact the Earth has a magnetic field

and an atmosphere.

There is some protection from these galactic particles

that we get from the sun as well

and we see that the number varies across the solar cycle.

The sun's magnetic field extends out and surrounds the Earth

and it deflects the galactic cosmic rays from us.

But the sun is both our friend and our foe

and the sun itself is an amazing particle accelerator

and it's able to produce events where particles like electrons

and protons get accelerated almost to the speed of light as well,

and they shower down on the Earth.

So whereas the particles coming from the galaxy have very high energies,

they form a sort of background radiation.

The sun is capable of these very strong high-flux bursts

and they can be very, very dangerous for astronauts. And I'll give you

a bit of information about the normal flow of particles

in the solar wind. So, the sun all the time has a flow

that takes a few days, maybe four days,

to get from the sun, through 150 million kilometres of space, to us.

When an energetic particle event happens,

they get here within half an hour.

And the storm can go on for days.

And there are so many of them pouring down onto the astronauts.

Once you're above the Earth's atmosphere and the edges

of the Earth's magnetic field, you have very little protection.

In fact, the particles are so energetic, they don't even see

our magnetic field, they just come rushing in.

And so if you're an astronaut outside the protection of the magnetic field

and one of these solar flares, solar particle events, happens,

-what happens to you?

-So, you would be irradiated.

And you could have a mild effect - radiation sickness,

disorientation - but it could be fatal.

And Tim Peake's crew has just gone out on a spacewalk.

Would this sort of event have been a risk for them

-if they were outside their vehicle on that spacewalk?

-It would have been.

So, they would not have been allowed to go out on a spacewalk

had there been a solar particle event happening.

They are so dangerous.

They would have to have been inside the space station

and also gone to an area where they get more shielding.

Because to stop them, what you want is material that the particles

can run into, collide with, and then not reach your body.

This sounds like a disaster.

We want to go exploring the rest of the solar system.

It sounds to me like we should just stay at home and cower underneath

the Earth's magnetic field and our atmosphere, if we can.

It's a huge challenge and I think it's the main challenge to overcome

if we do want to successfully move out towards Mars.

-We've got to keep humans safe.

-It doesn't sound like we can. We can't

build a spaceship out of lead. What will we do about shielding?

Some people are thinking about using the water that you would need.

-Water's a good shield?

-That would be a good shield.

In fact, it turns out that having a material that has light particles

in it, like hydrogen, is quite a good approach.

Water, OK, it weighs quite a lot, but it would make a good shield

if you had it running through the walls of your spacecraft.

Lucie, thank you so much.

APPLAUSE

Now, there's not just measuring the radiation environment

inside the space station.

They're having a look at what effects that has on life outside

the space station and particularly with this particular facility here.

This is the exposed facility and it's a British-led experiment

up on the space station now with Tim Peake. This has been taken up

and bolted onto the outside of the space station and it's pretty cool.

Inside, you have layers, and it's outside the space station

and they're exposing the contents of this to radiation.

Now, inside there are fungi, bacteria,

there's even some seeds, and they've layered it

so that one layer is the same as Mars in terms of radiation environment,

one layer is the moon, and one is just the vacuum of unprotected space.

And you think that everything should die up there, but some of this stuff

does reasonably well, and there is one creature in particular

that is just incredible in radiation.

We've got some right here, if they haven't run away.

Let's have a look. These are tardigrades.

This is a super-tough creature.

You think you'd do well against this creature

but you wouldn't, cos you can boil it and it says, "Meh."

And you can freeze it down to nearly absolute zero, apparently,

and it doesn't care.

You can subject it to huge pressure and it doesn't care.

You can send it to space without a spacesuit.

To be fair, it's very hard to make a spacesuit for these things.

And, most amazingly of all, you can subject it to huge doses

of ionising radiation and it kind of likes it.

LAUGHTER

That is a tardigrade. They're also called "water bears"

and some people think they're a bit cute.

I think they're just kind of weird, really, but they're super tough.

Now, the tardigrade can survive doses of radiation that none of us can,

and radiation is super bad for you.

It can damage your cells at the molecular level,

cause all sorts of problems with your DNA

and your DNA's ability to replicate and produce healthy new cells.

So, how does the tardigrade manage to survive

when we would do really badly?

And for that, I am going to need not one, not two, not three,

but four volunteers.

Let's go here.

And...let's have...you.

OK, come on.

OK, and... OK, off the front row... OK, how about you? Good.

And one more from over here.

How about you? OK, come on, let's go.

OK, so you are going to be Team Tardigrade.

This is tardigrade DNA double helix.

And you are going to be Team Human,

which you would think would be good, but just wait.

This is a human DNA double helix.

You are the repair mechanisms for this DNA

and in a minute, we're going to expose them to some radiation

and you are going to try and repair them.

But we should get out of the way of the radiation,

cos we're about to irradiate this whole field,

so come on, follow me, quick, let's get out the way.

Come on, come on, let's go.

Now, the rest of you, while we've cleared the areas,

should prepare your radioactive particles.

-Everyone ready? AUDIENCE:

-Yes!

OK.

Three, two, one. Irradiate!

LAUGHTER

CHEERING

APPLAUSE OK, come on, come on, come on.

OK, there was a bit of damage there

and then there was a solar particle event!

OK, so I think you might need some help with these.

So, we'll get some people on to help you.

I hope you remember what they looked like before.

Cos I want you to build exactly the same DNA helix.

So, repairers, Team Tardigrade, are you ready?

-HALF-HEARTED:

-Yes.

-Oh, wow.

LAUGHTER

-Team Human, are you ready?

-Yes!

LAUGHTER

They brought it. They brought their game.

OK, three, two, one, repair!

So, right now, they are trying to repair the damage that was done

by your, frankly, not very good irradiation.

They are trying to build the towers that existed beforehand.

Now, Team Tardigrade here...

are doing all right, I suppose.

And Team Human, they're nearly there. So are Team Tardigrade.

Basically, hurry up.

LAUGHTER

Oh, are we...?

Are we nearly there?

Well done. All right, well done, guys.

All right, come and stand here.

Fantastic. And come and stand here. All right, let's see how you did.

In a minute, we're all going to look at the screens

and see before and after.

OK, so up on the screen, this is the human tower before and after.

You haven't done bad, actually.

A silver row, then a green row, then the blue row.

And then... Hold on.

Blue and green, yellow and green. Oh, dear.

And then it goes completely wrong and you really haven't done very well.

That is not a good repair job, people. Too quick, I think.

OK, let's have a look at Team Tardigrade, before and after.

Two silvers, two greens, two blues, two blues, two greens, two yellows.

You're perfect all the way

up to the top.

That's amazing. Well done. Team Tardigrade win!

But... But...

You did have a bit of help, didn't you?

And not just from John, because Team Tardigrade, I'm sorry to tell you,

Team Human, had a little guide to how to put their tower together.

That's the trick. That's how tardigrades do it.

Tardigrades have a superior repair mechanism, so when they get hit

by radiation, they can repair their DNA better

and much more effectively than humans.

So, tardigrades win, at least in a radiation field.

Thank you very much. Go back to your seats, thank you.

APPLAUSE

And radiation is a huge problem if you want to carry on journeying

deeper and deeper into space and particularly if you want to go

to my favourite destination, and that is the planet Mars.

Now, as far as we've ever been from Earth is the moon at 250,000 miles.

That's about the distance you can get a car to drive

before the engine falls out the bottom.

But Mars sits out there at huge distances.

It is the fourth planet from the sun.

To get there, you need to travel for hundreds of millions of miles.

The time for a mission to Mars is, at the very least,

a year and a half and maybe up to three years.

So, you're talking about 1,000 days in space, which is crazy.

And then you start to think, "What am I going to pack?"

Well, packing for space is hard and to help me show you that,

I am going to need a volunteer.

OK, OK, all right. Let's have...you.

-What is your name?

-Ashta.

-Asher?

-Ashta.

-This is your suitcase.

I've packed it for you for a weekend on Mars, all right?

And this is pretty good.

So, what do you think you need for a weekend away?

-Um...

-Some clothes?

-Spacesuit.

-Yeah, a spacesuit would be good.

We'll start with a spacesuit. So, come round here.

Just stand here. Perfect.

Spacesuits? Well, spacesuits... Space clothes is close enough.

So, let's have some of that. So, we've got some space clothes.

You're going to have two pairs of pants.

It's a weekend, let's get two pairs of pants.

OK, I think they're in there.

So, you've got...clothes. What else do you need?

You probably need to take some food, don't you?

Yeah. So, here's some food for you.

Let's find the food in here.

Ah, yeah, here's your food.

We've got some space food for you. This is sausage casserole.

Are you a fan of sausage casserole?

Bit of flour. Um, er...and...

What's that one there?

A bit of toffee pudding. You up for that?

OK, all right. And what else have we got?

You've got to take your water with you. If you were an adult astronaut,

you'd need to take about three litres a day.

So, we'll get three litres of water out. Six litres for the whole day.

And it's not just your water. You've got to take your oxygen.

So, here's some life support for you. LAUGHTER

Let's just get that there.

And it's not just your oxygen - you need a towel to dry yourself off.

This is a very nice towel, actually.

It's got a good message for people in space.

And what else would you want?

Some reading material... cuddly toys...and a wash kit.

And that is for two days in space. OK?

So, multiply that by 500 for 1,000 days in space and multiple that

by a crew of six and we're in trouble, aren't we?

We're never building a spaceship big enough.

You're dropping it all, and I've packed that very carefully for you.

We're not ever getting into space light, are we? No.

We're going to have to think again. Thank you very much, Ashta.

It's not going to work, is it? We can't pack like that for Mars

because the spaceship would be so big,

we'd never get it off the ground,

let alone get it hundreds of millions of miles into space.

So, how are you going to do it? And the answer is you're going to have to

get better at reusing everything.

And I really, really, really mean everything.

Now, for this next one I am going to need...

..a volunteer.

So, now, this is a glass of my finest...

urine.

LAUGHTER

I need a volunteer

to drink this urine.

LAUGHTER

OK, OK, listen, when someone says, "I need a volunteer to drink urine,"

you do not volunteer for that! OK?

That's the most important lesson I'm going to give you today.

There are hands still up!

It is not socially acceptable, ever, to drink urine, OK?

There's a reason you have kidneys

and that's because the stuff in your urine,

the stuff that your kidneys take out - the potassium, sodium,

urea, phosphates - that 5% of the urine is really, really bad stuff,

which is why you put it on the outside of you.

OK? So, when someone says, "Do you want to drink my urine?"

you say no!

There is only one acceptable way to drink urine

and that is...

if you have some special treatment.

OK? And so this is a special bag

that recycles urine, OK?

And what it does, it's a bag within a bag

and I think I'm going to need another glass here.

But there's a bag within a bag

and the bag inside is actually

a semi-permeable membrane.

You pee into this red port here,

the urine goes into the bag, and the bag inside will allow water

to go through, but not all the nasty stuff.

Now, to encourage the water across, this green port you put a syrup in

and the syrup has a very high osmotic pressure,

lots of molecules that draw the water across

and you get clean water with all the nasty stuff left outside.

This, very helpfully, if you can see that there, has a port that says,

"Dirty water in."

"Sports syrup in. Clean drink out."

So, do not drink out of the red port.

LAUGHTER

This is one I made earlier, cos osmosis takes a while. And, uh...

We're going to pour it in here now.

Here's the thing, because you've got some syrup in there,

it kind of looks like pee even after it's been reprocessed.

LAUGHTER

And...to be honest...

Do you want to have a smell of that?

-It smells like...?

-Smells...

-quite a lot like urine.

-It smells a lot like pee. Do you want to smell?

So, it looks a bit like pee and still smells like pee.

But this is perfectly safe to drink because osmosis has treated it and...

GIGGLING AND EWS

To be honest, it really does still... LAUGHTER

..taste like pee. All right.

Now, Tim has a much better way of recycling his pee.

He does recycle it up there.

Tim Peake and his crew have a really quite cool mechanism which not only

recycles their urine, but also their sweat

and the vapour they breathe out of their mouths.

And they're recycling up to 98% of their body water.

That's really horrible, that stuff, it's just so horrible.

That is how you recycle urine. Um...

But what if you had a way of recycling water, that was also

a way of recycling your atmosphere, that was also a source of food?

And I have one of those right here on the shelf. It's called a plant.

That's what you'd like to do,

you'd like to take a bunch of plants with you into space.

But that turns out to be really hard, cos you're in a spaceship

and there's no natural light

and there's no soil, cos there's an infection risk from the soil.

So, how do you grow plants in space?

I don't know, but I know a man who says he can.

Let's welcome Alistair from the Royal Horticultural Society.

Alistair, I'm just going to put this down.

Now, what's this?

This is a closed-loop system that will feed us, basically.

-It produces the food for you to eat.

-This is grow-your-own space food?

-Yeah.

-And you can do something with that to make something

-I would want to eat?

-Yeah, yeah. It'd be a bit smaller, but yeah.

I'm not convinced, but you tell me that I will be, so to show me,

I'm going to need a volunteer.

All right. Let's have...

you. OK, good, all right.

-What's your name?

-Findlay.

Findlay, you're going to go over here to Christian,

who's going to help you over there.

Apparently, you're going to put something together

that we can grow in space.

All right. Convince me of this, cos I'm just not buying it.

So, this is a system that you can grow in space - how is that possible?

We've got no sunlight in space.

So, the lights here, you've got red and blue.

Now, plants photosynthesise at the red and blue lights, so it optimises

the amount of chlorophyll a and b in relation to efficiency.

You also have some green lights in there.

You've got a water system here

which is a closed water system, because there's near zero gravity.

Water would be floating out of this at the moment, which is why

they're completely closed in those systems.

And so this is a system that could be grown in space

and I think the guys have tried to do that.

I think we've got some video of that up here.

So, this is some weird space plants. What colour are those plants?

Yeah, so this is the Veggie plant, they're the purple plants.

-Why are they purple?

-That's in relation to the anthocyanins

that they have in there, so it's the chemistry within those.

Those are the things that make leaves turn a different colour in autumn.

-That's right.

-OK.

-And you can see it's a collapsible system,

so this is called a Veggie system and leaves sort of come up.

And what plants have we got here?

I've heard of five a day, but this is ridiculous. What's this?

We've got rice here. We've got wheat here.

We've got basil. We've got soya here.

We've got tomato here. So, there's a number of crops here

that we would probably want to take up to space.

I could see how you could grow this all in space, but what food

are you going to make with that?

BELL DINGS Oh.

Findlay, what's going on?

We're trying to grow space food here

and you're just mucking around in the kitchen. What's going on?

-Hopefully pizza.

-Hopefully a... You can make a pizza with all that?

Oh, yeah, you can make cheese out of soya. Space pizza.

Christian, let's see some space pizza in your special space-age oven.

Ladies and gentlemen, space pizza.

I think you need a bit more basil on there. Findlay, come and grab

some of this. There you go,

go and sprinkle that on, off of our hydroponic system.

Who's the hungriest cameraman?

It always looks like Joe. Let's feed Joe.

Let's make sure that Joe can... LAUGHTER

You just carry on with that, Joe, while we carry on with the programme.

Alistair, Findlay, thank you so much, great to see you. Thank you.

OK, so even if we master the art of bringing our life support with us

in some sort of form that we can regenerate,

we've still got other problems.

And that's part of the mission of Tim Peake's crew aboard the ISS.

So, let's go back to that emergency spacewalk that Tim's crew had to do

at the start of his mission.

Astronaut Dan Tani is going to talk us through what is possibly

the most dangerous thing that any astronaut ever has to do.

Dan, why are they having to do this spacewalk?

Cos this wasn't expected, this wasn't in the plans for Tim.

He wasn't expecting to get up onto the space station

-and almost immediately have to help supervise a spacewalk.

-Absolutely.

They were doing a routine move of what's call the mobile transporter.

The mobile transporter is like this trolley that goes back and forth...

-We can see it here.

-Yeah, let's talk about that.

And so they were doing a routine manoeuvre from one work site

to another and, unexpectedly, it got stuck.

It had to release from one work site

and it got stuck before it could get to the other work site.

-And they don't know why.

-And that's a big deal because they depend

-very heavily on that arm.

-It's a very big deal

because two of the supply ships that bring cargo to the space station -

the food, experiments, sometimes oxygen and critical things -

are grappled by that arm, and right now, that arm is completely useless.

It's not hooked up to the space station and so they need to get that

mobile transporter locked into place so the arm can be operated.

-Going out the lock there.

-Yeah, here they go.

If they are unsuccessful at performing this EVA,

it will put a halt to everything on the space station.

They have got to fix this mobile transporter.

They cannot continue operating the space station

with the mobile transporter in this position.

This is a helmet camera.

We can see their perspective of what they're doing.

'I'm going to start heading in that direction.'

So, they're navigating their way to their destination

and that's what they're doing now, hand over hand,

working their way around the structure, out that airlock

and out towards the CETA cart, this transporter we've been hearing about.

The space station is so large, there are labels out here with arrows

that say "Airlock", so that you know how to get home.

We'll see those.

Because the last thing you want is to be so disorientated, like,

"I'm not sure where I'm going."

And we have, basically, how-to-get-home arrows out there.

Is it easy to get lost on the outside?

It's very surprisingly easy to lose your orientation

and not be sure, "Am I on top? Am I on bottom? Am I behind?"

Especially if it's dark and all you see are a couple of handrails.

Right, and that's a good point to make, cos right now,

they're in sunlight. They time the walk to start with an ISS sunrise

and then they've got 45 minutes before the sun goes down

and this view will go dark and only be illuminated by their...

Helmet lights. There are a few external lights

on the space station.

Let's have a listen to the downlink, if we can hear it.

'..on the starboard CETA cart.

'We'll initiate the release of the brake handle

'which is believed on the starboard CETA cart to be the suspect

'that is preventing the movement of the mobile transporter.'

-'It's started moving forward now.'

-'OK, we copy that.'

So, they are at their destination.

They're there, yeah, they're working it.

What they want to do is make sure the brake is the problem

and there's no other problem.

INDISTINCT TECHNICAL CHATTER

'OK, copy that. Then you can go ahead and translate up to face one

'and you're looking for handrail 35-23, which is in bay 02,

'for your green hook.'

So, that's a very specific instruction.

Not just "the handrail" - a numbered handrail and telling him

where he's going to find it. How useful is that information to you

-when you're walking?

-It's critical.

They're instructing him to go to that handrail

and take his safety tether

and attach it to that handrail, because in the whole choreography,

they don't want to cross their tethers

or get it caught up in anything else.

Right now, Tim Peake is still in the vehicle.

I guess he's monitoring their progress.

He's certainly monitoring what's going on,

making sure he understands where everybody is,

but he has to be acutely aware of what's happening on the outside

so that if anything happens, he's ready to jump into action

and receive them in the airlock.

-It sounds like they might just be about to get this cart moving.

-Yeah.

Done everything they need to do in the CETA cart

and it sounds like they're giving the go and getting out of the way.

They're getting out the way

so that Mission Control can move that cart automatically from the ground.

An instruction's going to be issued from Mission Control and get that

cart moving and we're going to see that in the next couple of minutes.

'OK, I'm ready for motion whenever Tim and you guys are.'

'I'm ready for motion, too.'

'OK, we're putting in the last command.'

-'I see motion.'

-We do see motion on the mobile transporter.

'We see motion down here as well, that's good.'

-Inching towards its destination.

-Very slowly.

'OK, guys, good news, it appears to have reached

-'the work site centre, so we are a go to continue.'

-It's a big success.

They couldn't be happier how things went on the spacewalk.

INDISTINCT RADIO CHATTER

-'I'm going to tell you to stop there for a second.'

-'OK.'

-'Right when you get to that trunnion pin.'

-'OK, will do.'

He's taking a picture of Tim Kopra, that's what he's doing.

He saw a good picture, so he's setting up a picture.

-So, enough time for selfies.

-Right, yeah.

I think they're doing pretty well. It is remarkable.

The crew have gone out the airlock,

got onto the bit of the space station that was broken,

they have got that brake off, they've moved into place,

tiny fingers crossed to make sure that that couples into the power

so they can move it again.

But I think they have literally saved this mission.

-I think it's a round of applause for them.

-I believe they have.

APPLAUSE

Exciting stuff, but only 15 people have ever flown for more than

200 consecutive days in space. Two of them are in orbit right now.

One of them is Scott Kelly, the guy on the right in this picture,

and he's trying to work out the effects of space on the human body

to prepare us for that next great leap into space.

And he's pretty good in space.

You can see he's very comfortable, but he...

He's still trying to find out how to survive for longer and longer.

That's the goal of this one-year mission.

Right there you can see him on the space gym.

He has to spend a couple of hours a day on that just to preserve

his muscle and bone and his heart,

cos otherwise he comes back like a big, fat couch potato.

And the problems you have because of weightlessness you can avoid

if you do with gravity what we do with our light, heat,

sources of power, drink and food,

and that is take gravity with you.

Now, that's not as sci-fi as it sounds. That's easier said than done.

All you need to do is make use of a bit of circular motion,

a bit of centripetal acceleration and a bit of centrifugal force.

We've got four astronauts on this mission. Are you nervous?

AUDIENCE MUTTERS

No? You really, really should be.

This didn't go well in rehearsals. Here we go.

And...there we go on our space mission!

Oh, my gosh. OK, whoa!

So, that was another partial success. But you get the point.

If you can spin something fast enough and hard enough, you can create...

it's not artificial gravity, really, actually.

This is acceleration. Acceleration and gravity are equivalent.

So, this is gravity, really,

in a sense, when we spin the vehicle. But here's the problem -

to get a lot of gravity, if your circle is small,

you need to spin very, very fast.

The only way of producing adequate gravity and not spinning fast

and not making yourself horribly dizzy is to spin something big.

Now, bizarrely, Nasa have done those experiments.

On the screen we can see some experiments, and while we get

this mess cleaned up, we can see... I think this is from the 1960s.

This is Nasa trying to work out how big a radius

and how fast you can spin people to get them to tolerate

rotational vehicles so that you can create artificial gravity.

This guy's being suspended by the crane above him on his side

and he's walking around this rotating structure.

What they found when they did lots of these experiments

is that everyone gets dizzy at a point, but some people...

There are some rates of rotation that everyone can manage to cope with.

And that rate of rotation is four revolutions per minute.

No matter how bad you are on a fairground ride,

after a certain amount of time, you can all manage

four revolutions per minute.

So, if that's your limiting factor, if you have to spin the vehicle

at four revolutions a minute and you want to make one G of load

in that vehicle, then how big does your vehicle need to be?

I'm going to save you the maths here, because the answer is

a vehicle with a rotating radius of about 62.5 metres.

Now, how big is that?

It is actually exactly the same size - almost the same size -

as the London Eye. Now, who's ever ridden in the London Eye?

OK. It does not go round four times a minute.

If you're on it and it goes round four times a minute,

try and get off cos it's going wrong. LAUGHTER

But we can make it turn at four revolutions a minute

and that's what it looks like going round at four revolutions per minute.

All the people on it that day wanted their money back.

But if this was your space vehicle going through space,

turning at that sort of rate,

then the people in the pods wouldn't be standing on the floors,

they'd be on the edges,

being able to stand up, because there would be one G of load.

One G is the force of gravity we have on Earth, that's great.

But that London Eye is as big across as the space station is long.

And it takes a lot of effort to build that. Took 15 years

to build the space station, and sending vehicles like that to Mars

is a huge, huge engineering challenge.

So, what other option do you have?

Well, when I worked for Nasa in 2007,

I was part of an experiment to answer that question.

And we thought, "What if you could get a centrifuge that you could fit

"inside an ordinary vehicle?"

So, inside a module that looks rather like that.

As big as that that you could send up to space on an ordinary rocket.

And you could spin something quite fast to generate artificial gravity.

And you can do that, you can get a centrifuge that would almost fit

on the floor here, and I think we've got some footage of that.

This is the Short Radius Centrifuge in Houston.

That is my former mentor at Nasa,

now the Director of Life Sciences at Johnson Space Center.

He's got his eyes closed cos I don't think he liked being on it very much.

Now, you say, that's going to be rubbish, flying to Mars,

spinning on that all day.

But here's the kicker - you don't have to spin on it all day.

If you spin really fast, fast enough to give you more than one G of load,

then you can give gravity like you would give the dose of a drug.

And you can take that gravity dose twice a day

for one hour in the morning, one hour in the afternoon,

and that is enough to provide quite a lot of protection.

The absence of gravity which has been your enemy all along isn't a problem.

Actually, when gravity returns, it is your enemy.

And to get safely onto the surface of Mars, you need to be able to stop.

And there's one thing that rocket scientists will tell you

and that is that the hardest two things in all of rocket science

are starting and stopping again.

And so I thought we should bring on an expert in stopping

when you get to Mars.

So, it's my great, great pleasure to welcome our very special guest...

an engineer from the Jet Propulsion Laboratory in Pasadena

and one of the lead engineers on the Mars Curiosity Rover,

Dr Anita Sengupta.

Now, Anita... Come and give us a hand here, you two.

Come and give us a hand to stretch this out.

-What have you got here?

-This is a disk-gap-band parachute

and it's specially used on Mars and the reason for that is, on Mars,

when you enter the atmosphere, you're coming at very fast speeds,

and when you deploy the parachute,

you're coming in at supersonic speeds.

I'm experiencing all sorts of dynamic instability here.

-Have we got a working version of this?

-We do, actually.

We have one which is a subscale version.

Represents about 3% of the scale that we used on Mars

which we can show you now.

We're going to count in and then release the parachute.

Ready, everyone? Three, two, one.

There it goes.

-So, that is very impressive.

-It is.

It's very lightweight and so what's so unique about these parachutes

is they weigh almost nothing, but they're incredibly strong.

For reference, the parachute that we used for Curiosity,

it weighed only about 100lbs

but had to withstand a total load on of it about 65,000lbs of force.

I love that. It's a very interesting design, but I still don't get...

What's the fuss with stopping at Mars? We stop at Earth all the time.

You've got some video here of what it was like to stop at Mars.

You were one of the lead engineers for this,

the Mars Curiosity Rover, which was fantastic.

This is the size of a Volkswagen Beetle coming into Mars' atmosphere.

-Tell us what's happening here.

-At this point we're at hypersonic flow.

We've slowed down to around 1,000mph and the parachute deploys at mach 2,

two times the speed of sound, around 900mph.

It continues to slow down to subsonic speeds.

At that point, it's actually reached terminal velocity.

You can't go any slower, so you basically cut the parachute away.

Then the Rover is in freefall, descending towards the surface.

At this point, it turns on a total of eight main landing engines,

eight rockets firing towards the ground to slow it down even further.

That gets it down to around 200mph.

As you approach the surface, we start something very unique,

which is called the Sky Crane manoeuvre.

This is the first time we've ever done this on Mars.

We start to lower the Rover on a series of three tethers.

And the reason we do this is we actually make the Rover

the actual landing platform.

And it allows us to have these big, powerful engines firing

towards the ground, but at a safer distance away from the Rover

and away from the surface. Those three tethers then cut away.

That little rocket ship flies off 45 degrees to the side

and crash-lands - its mission is over.

And now the Rover is safely on the surface of Mars.

Wow, that's amazing.

APPLAUSE

That is, hands down, the coolest landing I have ever seen.

But this parachute, why does it have the gap?

It has the gap because it experiences something called

a supersonic instability. So, what you saw as it descended

from the ceiling was actually in subsonic flow.

In subsonic flow, the parachute is relatively stable,

but in supersonic flow, things look entirely different.

And we have a video which actually has the parachute deploying

at 2.7 mach, which is almost three times the speed of sound.

What you can see is it collapses and inflates like a jellyfish.

We don't want it to do that

but, unfortunately on Mars, that's what it does.

When it happens, you can actually cause the parachute to produce

less aerodynamic drag, which is what slows you down.

It can actually damage the parachute and make it fall apart

and so we were really concerned about this for the Curiosity Rover,

cos it was the largest parachute we'd ever built, and it also

was deploying at the highest mach number we've ever deployed at.

That is incredible. The gap allows it not to fall apart as it opens.

This is absolutely fantastic. I'm going to give you your parachute back

-cos I think you might want to use it again.

-Yes.

Anita Sengupta, everybody.

APPLAUSE

So, we can get there in one piece,

we can stop using one of Anita's incredible systems.

And then we're there.

And up on the screen now you can see a picture of one of the places

on Mars that I would like to visit.

This is the very beautiful dappled centre of Victoria Crater.

That crater, it's a real picture, it's 780 metres across.

It's been visited by the automatic rovers that have been, really,

the pathfinder missions for our future human exploration

and we've peered into that crater.

In its walls are sedimentary rocks, layers and layers of rock

that tell us about the history of Mars.

There is still so much left to explore, but we remain confident.

So much so that we've begun to think about the way

we would get home from Mars.

Now, there's a way of lightening your packing load by using

what you've got all around you on Mars.

And that's carbon dioxide.

Mars' atmosphere is about 99% carbon dioxide and you can use that.

It brings you some very important things - carbon and oxygen.

If you bring a little bit of hydrogen along with you,

and it turns out that's quite easy to do,

then you can make some useful materials with something

called a Sabatier reaction.

In a Sabatier reaction you can combine hydrogen

and carbon dioxide, and the product is methane and oxygen.

And that is enough to make some rocket fuel.

You don't usually think of methane as being something that can

propel people and objects into space, so I'm going to show you.

Andy, goggle time. And I think front row goggle time. Good, all right.

I know you think of methane as being a bit of a comedy gas

that cows fart out but, actually, it can propel rockets.

Now, Andy's going to light this one because there's a trick to it

and he says it has a more...

He technically described it earlier on as a more "flamey flame".

LAUGHTER

So, this is methane.

AUDIENCE GASP

We are on our way home

and there's just time for Tim to say a final goodbye.

So, it's been great talking to everybody

at the Royal Institute Christmas Lectures

from the International Space Station.

I'm sorry I couldn't be with you in person,

but I certainly think that I've got the most privileged position

to be here onboard at the moment

and looking down on the beautiful planet Earth.

So, to everybody back there, goodbye.

Thank you all for sharing in Tim's adventure.

But what you've seen here has been the adventure of our lives.

These are people who make not just Tim's mission happen

but all of science happen.

This has been our adventure.

And it will be yours and yours and yours and yours and yours.

This is the adventure of your generation

and it's time you started it.

Thank you.