0:00:02 > 0:00:03INDISTINCT LIVELY CHATTER
0:00:03 > 0:00:05'Glad to see you.'
0:00:08 > 0:00:11This was where the adventure starts for me.
0:00:11 > 0:00:151975, my parents take me downstairs to watch
0:00:15 > 0:00:17the Apollo-Soyuz Test Project -
0:00:17 > 0:00:21the final mission of Project Apollo and its famous first handshake
0:00:21 > 0:00:26between Russian and American astronauts.
0:00:26 > 0:00:3140 years later and we see the fruits of that collaboration,
0:00:31 > 0:00:35up there on the International Space Station, Tim Peake's mission.
0:00:35 > 0:00:40That platform is a platform for peaceful collaboration in science
0:00:40 > 0:00:47and exploration, and it is the jumping off point for new adventures.
0:00:47 > 0:00:53This lecture is all about the next frontier and that frontier...
0:00:53 > 0:00:54is your frontier.
0:01:09 > 0:01:11APPLAUSE
0:01:18 > 0:01:23Thank you and welcome to the 2015 Christmas Lectures.
0:01:23 > 0:01:26I'm Dr Kevin Fong, I'm a medical doctor, and I used to work with Nasa,
0:01:26 > 0:01:28helping them protect astronauts
0:01:28 > 0:01:32as they went about the business of exploring space.
0:01:32 > 0:01:35This is the final lecture in our series
0:01:35 > 0:01:39and in this lecture we have our sights firmly fixed on the future
0:01:39 > 0:01:43and what it's going to take with the edge of all that science,
0:01:43 > 0:01:47technology and engineering has to offer us to protect astronauts
0:01:47 > 0:01:52as they go about trying to go further and deeper into space.
0:01:52 > 0:01:59But first, let's go to Tim Peake and the ISS to look at
0:01:59 > 0:02:01the unexpectedly dramatic start
0:02:01 > 0:02:05to Tim's first few days aboard the station.
0:02:08 > 0:02:13Up on the screen just there you can see Tim, who's reading a checklist.
0:02:13 > 0:02:16On the other side of that door are his crewmates, Tim Kopra
0:02:16 > 0:02:19and Scott Kelly, who are in the airlock in their suits,
0:02:19 > 0:02:22getting ready to go out the door on a spacewalk - which is pretty much
0:02:22 > 0:02:26the most dangerous thing astronauts ever have to do.
0:02:26 > 0:02:29INDISTINCT TECHNICAL CHATTER
0:02:29 > 0:02:33Now, we'll be seeing more of how that spacewalk turned out
0:02:33 > 0:02:36later on in this lecture,
0:02:36 > 0:02:41but first, let's have a look at how much of space we've already visited.
0:02:41 > 0:02:45Let's make a constellation of everywhere we've been to explore.
0:02:45 > 0:02:48Now, these are our lights of exploration
0:02:48 > 0:02:53and this is the first light in 1957.
0:02:53 > 0:02:54Sputnik.
0:02:54 > 0:02:57You're going to be Sputnik for me - who's going to be Sputnik? Well done.
0:02:57 > 0:02:59All right, so Sputnik in '57.
0:02:59 > 0:03:03And then, in '61, the first human, Yuri Gagarin,
0:03:03 > 0:03:05goes into low Earth orbit.
0:03:05 > 0:03:09And by the end of that decade, famously, we're on the moon.
0:03:09 > 0:03:12Six crews, 12 people to the surface of the moon,
0:03:12 > 0:03:16and in that same decade we go to our neighbours -
0:03:16 > 0:03:18Mariner 4 in 1964
0:03:18 > 0:03:23takes the first photographs of the Red Planet of Mars.
0:03:23 > 0:03:26And then we go to our nearest neighbour, to Venus.
0:03:26 > 0:03:30And then we master the art of the slingshot
0:03:30 > 0:03:35and we're going to Jupiter, and then off to Saturn and their moons
0:03:35 > 0:03:40and suddenly nothing in the solar system is beyond our reach.
0:03:40 > 0:03:43We're in to Mercury, we're out to Pluto
0:03:43 > 0:03:45and now we stand with Voyager,
0:03:45 > 0:03:48the most distant man-made object from the Earth
0:03:48 > 0:03:53at 50 billion miles from Earth.
0:03:53 > 0:03:58And this is the constellation of exploration in space today.
0:03:58 > 0:04:00But wait.
0:04:00 > 0:04:02Where have we been with humans?
0:04:02 > 0:04:06Everyone who doesn't have a human mission, turn off your lights now.
0:04:08 > 0:04:14And what are we left with? We're left with low Earth orbits and the moon.
0:04:15 > 0:04:17And there's a reason for that.
0:04:17 > 0:04:21Rocket science is hard enough before you start trying to include people
0:04:21 > 0:04:24as parts of the payload.
0:04:24 > 0:04:26But with everything that we've learnt
0:04:26 > 0:04:28in the history of human space exploration,
0:04:28 > 0:04:30we're ready to go again.
0:04:30 > 0:04:33And particularly with the lessons we've learnt from the mission
0:04:33 > 0:04:36that Tim Peake is now involved in aboard the ISS,
0:04:36 > 0:04:40we are going back to the moon. We're going to go off to Mars and perhaps
0:04:40 > 0:04:46even more exotic destinations, and this time we're going with people.
0:04:46 > 0:04:49But where might we go?
0:04:49 > 0:04:53We could start with the moon. There is unfinished business there.
0:04:53 > 0:04:57And to explain what that business might be and why humans
0:04:57 > 0:05:00should go there, I'd like to welcome our very first guest -
0:05:00 > 0:05:03planetary scientist Dr Katie Joy.
0:05:03 > 0:05:06APPLAUSE
0:05:15 > 0:05:18Katie, I'm more of a Mars man myself
0:05:18 > 0:05:21so convince me that we need to send humans back to the moon.
0:05:21 > 0:05:24Cos we've been there. We've been there six times - 12 people.
0:05:24 > 0:05:27We have. We might have been there, but we've certainly not done that.
0:05:27 > 0:05:30So, we've sampled the near side of the moon from just six places.
0:05:30 > 0:05:33All that moon rock came back, it's located over at Nasa.
0:05:33 > 0:05:36But scientists around the world are still studying it to try
0:05:36 > 0:05:39and understand the moon's past and also to understand the moon's place
0:05:39 > 0:05:41in the solar system. So, we need to go back and we need to get more
0:05:41 > 0:05:44to really understand it. There's a lot more still to do.
0:05:44 > 0:05:47But really, there needs to be something really, really valuable
0:05:47 > 0:05:50up there to make it worth going. What is it that we would learn
0:05:50 > 0:05:52from the moon that would be so vital to us here on Earth?
0:05:52 > 0:05:55So, we can actually study the moon to understand our own origins,
0:05:55 > 0:05:57so the origin of Earth itself.
0:05:57 > 0:06:00But what's really exciting is the idea there may actually be
0:06:00 > 0:06:03early Earth material on the moon.
0:06:03 > 0:06:07So, samples, geological rocks from when life first started on Earth.
0:06:07 > 0:06:10These are not well-preserved on Earth because we have active
0:06:10 > 0:06:13plate tectonics, oceans, atmospheres
0:06:13 > 0:06:16that have destroyed these ancient rocks. But who knows?
0:06:16 > 0:06:18Big asteroids and comets were striking the Earth
0:06:18 > 0:06:20and they may be able to chip little bits off.
0:06:20 > 0:06:22That can travel through space
0:06:22 > 0:06:25and maybe they're just landing on the moon, ready for us to find.
0:06:25 > 0:06:29I think we're going to need a volunteer.
0:06:29 > 0:06:32Who would like to volunteer to help us explain this?
0:06:32 > 0:06:38All right, let's go up here and duck under there and we'll have...you.
0:06:38 > 0:06:39Yeah, come on.
0:06:47 > 0:06:50- Come and stand here and face the front. What's your name?- Joseph.
0:06:50 > 0:06:53Joseph, you're going to help me, you're going to need these.
0:06:53 > 0:06:56All right, Katie, I've no idea what we're going to do here, but tell me.
0:06:56 > 0:06:59OK, we're going to pretend this box is the early Earth,
0:06:59 > 0:07:03and this is examples of ancient rock sitting on the early Earth.
0:07:03 > 0:07:05We're going to pretend that these guys - here we go,
0:07:05 > 0:07:09we have some pretend asteroids. They look like iron meteorites to me.
0:07:09 > 0:07:12And we're going to hurl them at the Earth's surface.
0:07:12 > 0:07:16- So, that's a meteorite.- Goggles on, this sounds sort of dangerous.
0:07:16 > 0:07:19We're going to try throwing some into the box and the objective
0:07:19 > 0:07:22is to kick some oil out and have it try and hit the moon.
0:07:22 > 0:07:25Surface of the Earth, moon, you've got to get some rocks onto the moon
0:07:25 > 0:07:28- to convince me we need to go there. Go for it.- OK.
0:07:28 > 0:07:32Oh, Alex, you're going to need some goggles for this one, cos this is
0:07:32 > 0:07:36overwhelmingly dangerous, throwing stuff into that.
0:07:36 > 0:07:39OK, here we go. Joseph, give it your best shot.
0:07:39 > 0:07:42OK. We're not doing a grand job.
0:07:42 > 0:07:45We're sort of throwing at speeds of, you know,
0:07:45 > 0:07:48- a couple of metres a second.- OK. - We need to ramp it up a little bit.
0:07:48 > 0:07:52I told him he needed goggles, I look a bit stupid now, don't I? Um...
0:07:52 > 0:07:53Why isn't this working?
0:07:53 > 0:07:56Why can't you get the rocks off the Earth onto the moon here?
0:07:56 > 0:07:59So, when asteroids and comets hit the Earth, they're travelling at
0:07:59 > 0:08:02hypervelocity impact, so we need to get the material up about
0:08:02 > 0:08:0511 kilometres a second being spooled off.
0:08:05 > 0:08:10I think I have a hypervelocity impact simulator, specially built.
0:08:10 > 0:08:13This is our hypervelocity impact simulator.
0:08:13 > 0:08:17It's very hi-tech and, Joseph, you're going to help me fire it off.
0:08:17 > 0:08:20OK, Alex, you ready for this? OK.
0:08:20 > 0:08:24Our asteroid or comet is travelling closer and closer to the Earth,
0:08:24 > 0:08:26it's nearly getting ready to go.
0:08:26 > 0:08:28We're getting to the right sort of speeds.
0:08:28 > 0:08:33Let's count in. Three, two, one. Go!
0:08:38 > 0:08:40Joseph, come round here.
0:08:43 > 0:08:47Sorry about that, Alex. You need a new set of clothes.
0:08:47 > 0:08:50So, there's rock all over the moon all of a sudden.
0:08:50 > 0:08:54And that's, I guess, what we're looking for. Joseph, thank you
0:08:54 > 0:08:57very much for helping us. Ladies and gentlemen, Joseph. Thank you.
0:09:02 > 0:09:07Now, Katie, you have brought some of the moon with you tonight.
0:09:07 > 0:09:10I have some small chips of Apollo samples that were brought back
0:09:10 > 0:09:14by the astronauts, and we actually have a beautiful thin section
0:09:14 > 0:09:16of lunar rock under the microscope that you can see here.
0:09:16 > 0:09:20So, this amazing sample, it looks like a stained-glass window
0:09:20 > 0:09:23when we shine light through it. And this is actually a lava flow.
0:09:23 > 0:09:24We've got it on the screen.
0:09:24 > 0:09:27You can guys can see some spectacular colours.
0:09:27 > 0:09:29All these different colours represent different minerals
0:09:29 > 0:09:33and these formed in a lava flow that erupted from a volcano
0:09:33 > 0:09:36about 3.2 billion years ago. Just amazing.
0:09:36 > 0:09:41And this is a piece of rock brought back by the Apollo astronauts
0:09:41 > 0:09:44- nearly 50 years ago now.- Yeah.
0:09:44 > 0:09:46And you've studied it as part of your PHD, didn't you?
0:09:46 > 0:09:49Yeah, we study rocks like this to understand the moon's volcanic past.
0:09:49 > 0:09:52This one came from the Apollo 12 mission,
0:09:52 > 0:09:54so the second mission that went to the moon.
0:09:54 > 0:09:57But rocks like these may be really good traps for preserving
0:09:57 > 0:10:00some of these amazing archives of meteorites,
0:10:00 > 0:10:04and maybe Earth samples that have been delivered to the lunar surface.
0:10:04 > 0:10:06But they're incredibly beautiful to look at as well.
0:10:06 > 0:10:08Absolutely beautiful.
0:10:08 > 0:10:10It's amazing that so long after Project Apollo
0:10:10 > 0:10:13they're still teaching us valuable lessons.
0:10:13 > 0:10:17Sounds like a job for a planetary geologist like you on the moon.
0:10:17 > 0:10:18Would you go to the moon?
0:10:18 > 0:10:21So, we did get one geologist on the moon on the last mission
0:10:21 > 0:10:23and I would love to be a future geologist.
0:10:23 > 0:10:26I might try applying again next time. We'll see what happens.
0:10:26 > 0:10:28- Yeah, you applied to be an astronaut. - I did. We'll keep trying.
0:10:28 > 0:10:32Maybe somebody else in this room can have that opportunity to do it.
0:10:32 > 0:10:33Katie, fantastic to see you.
0:10:33 > 0:10:36You have convinced me we've got to send people back to the moon.
0:10:36 > 0:10:38- Thank you very much.- Katie Joy.
0:10:42 > 0:10:44Thank you.
0:10:44 > 0:10:47It is incredible, really, that we were able to go to the moon.
0:10:47 > 0:10:51Not just because we left behind on Earth, when we went to the moon,
0:10:51 > 0:10:54everything we take for granted in terms of life support
0:10:54 > 0:10:58here on Earth, but because we also left behind our protection
0:10:58 > 0:11:01from radiation, the protection we get from the Earth's magnetic field.
0:11:01 > 0:11:05Now, Tim Peake is on the space station,
0:11:05 > 0:11:09very carefully monitoring his own levels of radiation
0:11:09 > 0:11:13using a clever detector called the Timepix detector.
0:11:13 > 0:11:17And to explain a little bit more to you about this,
0:11:17 > 0:11:20I am going to need a volunteer.
0:11:20 > 0:11:24All right, let's go on a bit of a space mission.
0:11:24 > 0:11:26Let's have you.
0:11:32 > 0:11:36- What's your name?- Celeste. - Celeste, put some gloves on.
0:11:36 > 0:11:40We've got some bizarre stuff to show you here.
0:11:40 > 0:11:42Celeste, have you ever seen one of these things before?
0:11:42 > 0:11:46- Do you know what this is? - No.- This is a Geiger tube.
0:11:46 > 0:11:49Anyone ever seen one of these before?
0:11:49 > 0:11:51Yeah, yeah, yeah. OK, and it measures...?
0:11:51 > 0:11:55Radiation. OK, so we're going to turn it on.
0:11:55 > 0:11:58BEEP Oh! There you go.
0:11:58 > 0:12:02Celeste, point that at the audience, see how radioactive they are.
0:12:02 > 0:12:05This is a Geiger tube, it tells us how radioactive things are.
0:12:05 > 0:12:07The more radioactive they are, the more clicks you get off of this.
0:12:07 > 0:12:11It measures the ionisation as radiation comes in the front.
0:12:11 > 0:12:14No? No radioactive people? How about over there?
0:12:14 > 0:12:17No? OK, let's point that up to the sky. No real radiation.
0:12:17 > 0:12:18Hmm.
0:12:18 > 0:12:22That's because we're under a blanket of atmosphere
0:12:22 > 0:12:24and the Earth's magnetic field,
0:12:24 > 0:12:27so to show you some radiation, we've had to find something radioactive.
0:12:27 > 0:12:30And here at the Royal Institution, Charlotte, our curator,
0:12:30 > 0:12:33has some very exotic sources of radiation.
0:12:33 > 0:12:35Point it at this book.
0:12:35 > 0:12:37GEIGER TUBE CLICKS LOUDLY Charlotte, what is this book?
0:12:37 > 0:12:40This is notebook from William Crookes from 1903.
0:12:40 > 0:12:43I remember he's the bloke who made the very first medical -
0:12:43 > 0:12:47- this is not good is it? - medical X-ray tubes.- Yes.
0:12:47 > 0:12:49GEIGER TUBE CLICKS LOUDLY That sounds very radioactive.
0:12:49 > 0:12:51I might take that.
0:12:51 > 0:12:55All right, now this book, this is the page where he was talking about
0:12:55 > 0:12:58messing around with some radium salts?
0:12:58 > 0:13:01- Yes.- That's radioactive stuff.
0:13:01 > 0:13:03I think he was messing around when he was writing this page.
0:13:03 > 0:13:06- Which is the worst bit on this book? - Down the crease.- OK.
0:13:06 > 0:13:09GEIGER TUBE CLICKS LOUDLY
0:13:09 > 0:13:11LOUD BEEP Oh!
0:13:11 > 0:13:13LAUGHTER
0:13:13 > 0:13:14That's not good at all.
0:13:14 > 0:13:16CLICKING AND BEEPING
0:13:16 > 0:13:18OK.
0:13:18 > 0:13:20It's very, very, very radioactive.
0:13:20 > 0:13:23- Where do you keep this book, Charlotte?- In the RI Archives.
0:13:23 > 0:13:27- Yes.- In a metal box.- OK.
0:13:27 > 0:13:31Now, it's OK so long as we don't eat or lick the book. OK?
0:13:31 > 0:13:33So, do not eat or lick the book.
0:13:33 > 0:13:38Now, all that does is tell us how much radiation, Celeste.
0:13:38 > 0:13:41So, to do something rather more interesting,
0:13:41 > 0:13:44we'd like to know the sorts of radiation, how many particles.
0:13:44 > 0:13:46We're going to use the detector that is on Tim Peake's mission.
0:13:46 > 0:13:49This is the Timepix detector. You're going to help me start it
0:13:49 > 0:13:52so you're going to go round the front there and let's see
0:13:52 > 0:13:54how Mr Crookes' book does.
0:13:54 > 0:13:58OK, I'm going to take off the cover now over that page.
0:13:58 > 0:14:00So, every spot is a particle.
0:14:00 > 0:14:02The bigger the spot, the higher the energy. Here we go.
0:14:02 > 0:14:04Let's have a look
0:14:04 > 0:14:07at what we see.
0:14:07 > 0:14:09The book has suddenly...
0:14:09 > 0:14:11Oh, here we go.
0:14:11 > 0:14:12Here we go.
0:14:13 > 0:14:16And so all of those dots that you can see there
0:14:16 > 0:14:18are all particles of radiation or photons
0:14:18 > 0:14:20of energy coming through that detector.
0:14:20 > 0:14:23I don't think you can see it quite as well as we can see it here
0:14:23 > 0:14:25but, Celeste, that's a lot of particles, isn't it?
0:14:25 > 0:14:28Charlotte, I don't want to stand near this book any more
0:14:28 > 0:14:29so I think you should take it away.
0:14:29 > 0:14:32Celeste, I think your mum would be really happy if I sent you back
0:14:32 > 0:14:35to your seat as well. Thank you very much, Celeste.
0:14:39 > 0:14:41So, lesson one is don't eat radioactive things,
0:14:41 > 0:14:44but we have some data from the space station,
0:14:44 > 0:14:48from the detectors that Tim Peake is using, and this is it.
0:14:48 > 0:14:53And to help us understand what we're looking at, I'd like to welcome
0:14:53 > 0:14:58my guest, solar physicist Professor Lucie Green.
0:14:58 > 0:15:00APPLAUSE
0:15:10 > 0:15:14Lucie, what is that? It looks very worrying.
0:15:14 > 0:15:18That detector tells us not just how much radiation, but the type,
0:15:18 > 0:15:20so what type of radiation is doing that?
0:15:20 > 0:15:23So, this detector's able to pick up electrons,
0:15:23 > 0:15:27protons and also heavy atomic nuclei that come streaking in
0:15:27 > 0:15:31from all over our galaxy, travelling at almost the speed of light.
0:15:31 > 0:15:33Sounds slightly nasty.
0:15:33 > 0:15:36We don't have to worry about those so much here on Earth.
0:15:36 > 0:15:39You've got something here to explain that to us.
0:15:39 > 0:15:42That's right, so this is a set-up called a Planeterrella
0:15:42 > 0:15:44and it's a really nice way to demonstrate both the fact
0:15:44 > 0:15:46that the Earth has a magnetic field
0:15:46 > 0:15:50which guides electrically charged particles and also the effect
0:15:50 > 0:15:53of electrically charged particles on the Earth's atmosphere.
0:15:53 > 0:15:57And what's happening in here is that electrons, charged particles,
0:15:57 > 0:16:00are being accelerated through an invisible magnetic field,
0:16:00 > 0:16:03and you can see that's around that small sphere, glowing lights.
0:16:03 > 0:16:06And that's equivalent to the Northern Lights
0:16:06 > 0:16:10- and the Southern Lights, the aurora. - It's very, very beautiful even here,
0:16:10 > 0:16:12but there is a more beautiful way of seeing this
0:16:12 > 0:16:16and that's to be in space, and I think we've got some video
0:16:16 > 0:16:19of the Northern Lights as seen from space.
0:16:19 > 0:16:21Look at that.
0:16:21 > 0:16:24That green glow in the top, that's the Northern Lights,
0:16:24 > 0:16:27and this is from the space station looking down.
0:16:27 > 0:16:28It's such a fantastic view.
0:16:28 > 0:16:31The astronauts have the best view of the Northern Lights.
0:16:31 > 0:16:33I'm so envious of what they get to see.
0:16:33 > 0:16:36You see the thin atmosphere, the green glowing oxygen.
0:16:36 > 0:16:40But for us, it's incredibly important, cos it acts as a blanket
0:16:40 > 0:16:43to block out the effects of those galactic charged particles
0:16:43 > 0:16:45that we saw earlier on.
0:16:45 > 0:16:48So, we can protect ourselves from some of the most harmful radiation
0:16:48 > 0:16:52by sitting inside our blanket of magnetic field,
0:16:52 > 0:16:54so are we all right to keep carrying on exploring?
0:16:54 > 0:16:57Well, there are difficulties that we have to overcome,
0:16:57 > 0:17:00really severe difficulties. So, we've talked about particles
0:17:00 > 0:17:04coming from the galaxy and the fact the Earth has a magnetic field
0:17:04 > 0:17:05and an atmosphere.
0:17:05 > 0:17:08There is some protection from these galactic particles
0:17:08 > 0:17:10that we get from the sun as well
0:17:10 > 0:17:13and we see that the number varies across the solar cycle.
0:17:13 > 0:17:16The sun's magnetic field extends out and surrounds the Earth
0:17:16 > 0:17:20and it deflects the galactic cosmic rays from us.
0:17:20 > 0:17:23But the sun is both our friend and our foe
0:17:23 > 0:17:27and the sun itself is an amazing particle accelerator
0:17:27 > 0:17:32and it's able to produce events where particles like electrons
0:17:32 > 0:17:35and protons get accelerated almost to the speed of light as well,
0:17:35 > 0:17:37and they shower down on the Earth.
0:17:37 > 0:17:41So whereas the particles coming from the galaxy have very high energies,
0:17:41 > 0:17:43they form a sort of background radiation.
0:17:43 > 0:17:48The sun is capable of these very strong high-flux bursts
0:17:48 > 0:17:51and they can be very, very dangerous for astronauts. And I'll give you
0:17:51 > 0:17:54a bit of information about the normal flow of particles
0:17:54 > 0:17:56in the solar wind. So, the sun all the time has a flow
0:17:56 > 0:17:59that takes a few days, maybe four days,
0:17:59 > 0:18:03to get from the sun, through 150 million kilometres of space, to us.
0:18:03 > 0:18:06When an energetic particle event happens,
0:18:06 > 0:18:08they get here within half an hour.
0:18:08 > 0:18:11And the storm can go on for days.
0:18:11 > 0:18:15And there are so many of them pouring down onto the astronauts.
0:18:15 > 0:18:18Once you're above the Earth's atmosphere and the edges
0:18:18 > 0:18:21of the Earth's magnetic field, you have very little protection.
0:18:21 > 0:18:23In fact, the particles are so energetic, they don't even see
0:18:23 > 0:18:26our magnetic field, they just come rushing in.
0:18:26 > 0:18:29And so if you're an astronaut outside the protection of the magnetic field
0:18:29 > 0:18:32and one of these solar flares, solar particle events, happens,
0:18:32 > 0:18:35- what happens to you? - So, you would be irradiated.
0:18:35 > 0:18:39And you could have a mild effect - radiation sickness,
0:18:39 > 0:18:41disorientation - but it could be fatal.
0:18:41 > 0:18:44And Tim Peake's crew has just gone out on a spacewalk.
0:18:44 > 0:18:47Would this sort of event have been a risk for them
0:18:47 > 0:18:50- if they were outside their vehicle on that spacewalk?- It would have been.
0:18:50 > 0:18:53So, they would not have been allowed to go out on a spacewalk
0:18:53 > 0:18:55had there been a solar particle event happening.
0:18:55 > 0:18:56They are so dangerous.
0:18:56 > 0:18:59They would have to have been inside the space station
0:18:59 > 0:19:01and also gone to an area where they get more shielding.
0:19:01 > 0:19:05Because to stop them, what you want is material that the particles
0:19:05 > 0:19:09can run into, collide with, and then not reach your body.
0:19:09 > 0:19:10This sounds like a disaster.
0:19:10 > 0:19:13We want to go exploring the rest of the solar system.
0:19:13 > 0:19:16It sounds to me like we should just stay at home and cower underneath
0:19:16 > 0:19:18the Earth's magnetic field and our atmosphere, if we can.
0:19:18 > 0:19:21It's a huge challenge and I think it's the main challenge to overcome
0:19:21 > 0:19:23if we do want to successfully move out towards Mars.
0:19:23 > 0:19:26- We've got to keep humans safe.- It doesn't sound like we can. We can't
0:19:26 > 0:19:29build a spaceship out of lead. What will we do about shielding?
0:19:29 > 0:19:32Some people are thinking about using the water that you would need.
0:19:32 > 0:19:34- Water's a good shield? - That would be a good shield.
0:19:34 > 0:19:38In fact, it turns out that having a material that has light particles
0:19:38 > 0:19:41in it, like hydrogen, is quite a good approach.
0:19:41 > 0:19:46Water, OK, it weighs quite a lot, but it would make a good shield
0:19:46 > 0:19:49if you had it running through the walls of your spacecraft.
0:19:49 > 0:19:51Lucie, thank you so much.
0:19:51 > 0:19:53APPLAUSE
0:19:53 > 0:19:57Now, there's not just measuring the radiation environment
0:19:57 > 0:19:58inside the space station.
0:19:58 > 0:20:02They're having a look at what effects that has on life outside
0:20:02 > 0:20:07the space station and particularly with this particular facility here.
0:20:07 > 0:20:11This is the exposed facility and it's a British-led experiment
0:20:11 > 0:20:16up on the space station now with Tim Peake. This has been taken up
0:20:16 > 0:20:21and bolted onto the outside of the space station and it's pretty cool.
0:20:21 > 0:20:24Inside, you have layers, and it's outside the space station
0:20:24 > 0:20:28and they're exposing the contents of this to radiation.
0:20:28 > 0:20:32Now, inside there are fungi, bacteria,
0:20:32 > 0:20:35there's even some seeds, and they've layered it
0:20:35 > 0:20:40so that one layer is the same as Mars in terms of radiation environment,
0:20:40 > 0:20:45one layer is the moon, and one is just the vacuum of unprotected space.
0:20:45 > 0:20:49And you think that everything should die up there, but some of this stuff
0:20:49 > 0:20:54does reasonably well, and there is one creature in particular
0:20:54 > 0:20:57that is just incredible in radiation.
0:20:57 > 0:21:00We've got some right here, if they haven't run away.
0:21:00 > 0:21:03Let's have a look. These are tardigrades.
0:21:03 > 0:21:05This is a super-tough creature.
0:21:05 > 0:21:08You think you'd do well against this creature
0:21:08 > 0:21:11but you wouldn't, cos you can boil it and it says, "Meh."
0:21:11 > 0:21:14And you can freeze it down to nearly absolute zero, apparently,
0:21:14 > 0:21:16and it doesn't care.
0:21:16 > 0:21:19You can subject it to huge pressure and it doesn't care.
0:21:19 > 0:21:22You can send it to space without a spacesuit.
0:21:22 > 0:21:25To be fair, it's very hard to make a spacesuit for these things.
0:21:25 > 0:21:31And, most amazingly of all, you can subject it to huge doses
0:21:31 > 0:21:35of ionising radiation and it kind of likes it.
0:21:35 > 0:21:36LAUGHTER
0:21:36 > 0:21:39That is a tardigrade. They're also called "water bears"
0:21:39 > 0:21:41and some people think they're a bit cute.
0:21:41 > 0:21:45I think they're just kind of weird, really, but they're super tough.
0:21:45 > 0:21:50Now, the tardigrade can survive doses of radiation that none of us can,
0:21:50 > 0:21:53and radiation is super bad for you.
0:21:53 > 0:21:56It can damage your cells at the molecular level,
0:21:56 > 0:21:58cause all sorts of problems with your DNA
0:21:58 > 0:22:03and your DNA's ability to replicate and produce healthy new cells.
0:22:03 > 0:22:06So, how does the tardigrade manage to survive
0:22:06 > 0:22:10when we would do really badly?
0:22:10 > 0:22:14And for that, I am going to need not one, not two, not three,
0:22:14 > 0:22:16but four volunteers.
0:22:18 > 0:22:19Let's go here.
0:22:19 > 0:22:24And...let's have...you.
0:22:24 > 0:22:25OK, come on.
0:22:25 > 0:22:29OK, and... OK, off the front row... OK, how about you? Good.
0:22:29 > 0:22:31And one more from over here.
0:22:31 > 0:22:34How about you? OK, come on, let's go.
0:22:42 > 0:22:45OK, so you are going to be Team Tardigrade.
0:22:45 > 0:22:49This is tardigrade DNA double helix.
0:22:49 > 0:22:51And you are going to be Team Human,
0:22:51 > 0:22:53which you would think would be good, but just wait.
0:22:53 > 0:22:57This is a human DNA double helix.
0:22:57 > 0:23:00You are the repair mechanisms for this DNA
0:23:00 > 0:23:03and in a minute, we're going to expose them to some radiation
0:23:03 > 0:23:05and you are going to try and repair them.
0:23:05 > 0:23:07But we should get out of the way of the radiation,
0:23:07 > 0:23:09cos we're about to irradiate this whole field,
0:23:09 > 0:23:11so come on, follow me, quick, let's get out the way.
0:23:11 > 0:23:13Come on, come on, let's go.
0:23:13 > 0:23:16Now, the rest of you, while we've cleared the areas,
0:23:16 > 0:23:19should prepare your radioactive particles.
0:23:19 > 0:23:22- Everyone ready? AUDIENCE:- Yes!
0:23:22 > 0:23:24OK.
0:23:25 > 0:23:30Three, two, one. Irradiate!
0:23:35 > 0:23:37LAUGHTER
0:23:37 > 0:23:39CHEERING
0:23:39 > 0:23:42APPLAUSE OK, come on, come on, come on.
0:23:42 > 0:23:45OK, there was a bit of damage there
0:23:45 > 0:23:48and then there was a solar particle event!
0:23:48 > 0:23:52OK, so I think you might need some help with these.
0:23:52 > 0:23:54So, we'll get some people on to help you.
0:23:54 > 0:23:56I hope you remember what they looked like before.
0:23:56 > 0:23:59Cos I want you to build exactly the same DNA helix.
0:23:59 > 0:24:02So, repairers, Team Tardigrade, are you ready?
0:24:02 > 0:24:05- HALF-HEARTED:- Yes. - Oh, wow.
0:24:05 > 0:24:06LAUGHTER
0:24:06 > 0:24:09- Team Human, are you ready? - Yes!
0:24:09 > 0:24:10LAUGHTER
0:24:10 > 0:24:13They brought it. They brought their game.
0:24:13 > 0:24:17OK, three, two, one, repair!
0:24:17 > 0:24:20So, right now, they are trying to repair the damage that was done
0:24:20 > 0:24:23by your, frankly, not very good irradiation.
0:24:23 > 0:24:27They are trying to build the towers that existed beforehand.
0:24:27 > 0:24:30Now, Team Tardigrade here...
0:24:30 > 0:24:32are doing all right, I suppose.
0:24:32 > 0:24:37And Team Human, they're nearly there. So are Team Tardigrade.
0:24:37 > 0:24:39Basically, hurry up.
0:24:39 > 0:24:41LAUGHTER
0:24:41 > 0:24:42Oh, are we...?
0:24:42 > 0:24:46Are we nearly there?
0:24:46 > 0:24:48Well done. All right, well done, guys.
0:24:51 > 0:24:54All right, come and stand here.
0:24:54 > 0:24:57Fantastic. And come and stand here. All right, let's see how you did.
0:24:57 > 0:24:59In a minute, we're all going to look at the screens
0:24:59 > 0:25:02and see before and after.
0:25:02 > 0:25:06OK, so up on the screen, this is the human tower before and after.
0:25:06 > 0:25:08You haven't done bad, actually.
0:25:08 > 0:25:11A silver row, then a green row, then the blue row.
0:25:11 > 0:25:12And then... Hold on.
0:25:12 > 0:25:15Blue and green, yellow and green. Oh, dear.
0:25:15 > 0:25:21And then it goes completely wrong and you really haven't done very well.
0:25:21 > 0:25:24That is not a good repair job, people. Too quick, I think.
0:25:24 > 0:25:26OK, let's have a look at Team Tardigrade, before and after.
0:25:26 > 0:25:32Two silvers, two greens, two blues, two blues, two greens, two yellows.
0:25:32 > 0:25:33You're perfect all the way
0:25:33 > 0:25:35up to the top.
0:25:35 > 0:25:38That's amazing. Well done. Team Tardigrade win!
0:25:42 > 0:25:44But... But...
0:25:46 > 0:25:48You did have a bit of help, didn't you?
0:25:48 > 0:25:53And not just from John, because Team Tardigrade, I'm sorry to tell you,
0:25:53 > 0:25:58Team Human, had a little guide to how to put their tower together.
0:25:58 > 0:26:01That's the trick. That's how tardigrades do it.
0:26:01 > 0:26:04Tardigrades have a superior repair mechanism, so when they get hit
0:26:04 > 0:26:07by radiation, they can repair their DNA better
0:26:07 > 0:26:10and much more effectively than humans.
0:26:10 > 0:26:13So, tardigrades win, at least in a radiation field.
0:26:13 > 0:26:15Thank you very much. Go back to your seats, thank you.
0:26:15 > 0:26:18APPLAUSE
0:26:23 > 0:26:28And radiation is a huge problem if you want to carry on journeying
0:26:28 > 0:26:32deeper and deeper into space and particularly if you want to go
0:26:32 > 0:26:37to my favourite destination, and that is the planet Mars.
0:26:37 > 0:26:42Now, as far as we've ever been from Earth is the moon at 250,000 miles.
0:26:42 > 0:26:45That's about the distance you can get a car to drive
0:26:45 > 0:26:47before the engine falls out the bottom.
0:26:47 > 0:26:52But Mars sits out there at huge distances.
0:26:52 > 0:26:54It is the fourth planet from the sun.
0:26:54 > 0:26:57To get there, you need to travel for hundreds of millions of miles.
0:26:57 > 0:27:00The time for a mission to Mars is, at the very least,
0:27:00 > 0:27:04a year and a half and maybe up to three years.
0:27:04 > 0:27:09So, you're talking about 1,000 days in space, which is crazy.
0:27:09 > 0:27:13And then you start to think, "What am I going to pack?"
0:27:13 > 0:27:17Well, packing for space is hard and to help me show you that,
0:27:17 > 0:27:19I am going to need a volunteer.
0:27:19 > 0:27:23OK, OK, all right. Let's have...you.
0:27:30 > 0:27:37- What is your name?- Ashta.- Asher? - Ashta.- This is your suitcase.
0:27:37 > 0:27:41I've packed it for you for a weekend on Mars, all right?
0:27:41 > 0:27:44And this is pretty good.
0:27:44 > 0:27:47So, what do you think you need for a weekend away?
0:27:47 > 0:27:51- Um...- Some clothes?- Spacesuit. - Yeah, a spacesuit would be good.
0:27:51 > 0:27:55We'll start with a spacesuit. So, come round here.
0:27:55 > 0:27:58Just stand here. Perfect.
0:27:58 > 0:28:03Spacesuits? Well, spacesuits... Space clothes is close enough.
0:28:03 > 0:28:07So, let's have some of that. So, we've got some space clothes.
0:28:07 > 0:28:10You're going to have two pairs of pants.
0:28:10 > 0:28:12It's a weekend, let's get two pairs of pants.
0:28:12 > 0:28:14OK, I think they're in there.
0:28:14 > 0:28:18So, you've got...clothes. What else do you need?
0:28:18 > 0:28:21You probably need to take some food, don't you?
0:28:21 > 0:28:23Yeah. So, here's some food for you.
0:28:23 > 0:28:26Let's find the food in here.
0:28:26 > 0:28:27Ah, yeah, here's your food.
0:28:29 > 0:28:33We've got some space food for you. This is sausage casserole.
0:28:33 > 0:28:35Are you a fan of sausage casserole?
0:28:35 > 0:28:40Bit of flour. Um, er...and...
0:28:40 > 0:28:42What's that one there?
0:28:42 > 0:28:44A bit of toffee pudding. You up for that?
0:28:44 > 0:28:48OK, all right. And what else have we got?
0:28:48 > 0:28:51You've got to take your water with you. If you were an adult astronaut,
0:28:51 > 0:28:54you'd need to take about three litres a day.
0:28:54 > 0:28:58So, we'll get three litres of water out. Six litres for the whole day.
0:28:58 > 0:29:01And it's not just your water. You've got to take your oxygen.
0:29:01 > 0:29:05So, here's some life support for you. LAUGHTER
0:29:05 > 0:29:07Let's just get that there.
0:29:07 > 0:29:10And it's not just your oxygen - you need a towel to dry yourself off.
0:29:10 > 0:29:12This is a very nice towel, actually.
0:29:12 > 0:29:15It's got a good message for people in space.
0:29:15 > 0:29:18And what else would you want?
0:29:18 > 0:29:23Some reading material... cuddly toys...and a wash kit.
0:29:23 > 0:29:27And that is for two days in space. OK?
0:29:27 > 0:29:31So, multiply that by 500 for 1,000 days in space and multiple that
0:29:31 > 0:29:34by a crew of six and we're in trouble, aren't we?
0:29:34 > 0:29:36We're never building a spaceship big enough.
0:29:36 > 0:29:39You're dropping it all, and I've packed that very carefully for you.
0:29:39 > 0:29:42We're not ever getting into space light, are we? No.
0:29:42 > 0:29:46We're going to have to think again. Thank you very much, Ashta.
0:29:52 > 0:29:55It's not going to work, is it? We can't pack like that for Mars
0:29:55 > 0:29:57because the spaceship would be so big,
0:29:57 > 0:29:58we'd never get it off the ground,
0:29:58 > 0:30:01let alone get it hundreds of millions of miles into space.
0:30:01 > 0:30:05So, how are you going to do it? And the answer is you're going to have to
0:30:05 > 0:30:08get better at reusing everything.
0:30:08 > 0:30:11And I really, really, really mean everything.
0:30:11 > 0:30:15Now, for this next one I am going to need...
0:30:17 > 0:30:19..a volunteer.
0:30:19 > 0:30:24So, now, this is a glass of my finest...
0:30:24 > 0:30:26urine.
0:30:26 > 0:30:28LAUGHTER
0:30:28 > 0:30:31I need a volunteer
0:30:31 > 0:30:33to drink this urine.
0:30:33 > 0:30:34LAUGHTER
0:30:34 > 0:30:38OK, OK, listen, when someone says, "I need a volunteer to drink urine,"
0:30:38 > 0:30:40you do not volunteer for that! OK?
0:30:40 > 0:30:43That's the most important lesson I'm going to give you today.
0:30:43 > 0:30:46There are hands still up!
0:30:46 > 0:30:50It is not socially acceptable, ever, to drink urine, OK?
0:30:50 > 0:30:52There's a reason you have kidneys
0:30:52 > 0:30:55and that's because the stuff in your urine,
0:30:55 > 0:30:58the stuff that your kidneys take out - the potassium, sodium,
0:30:58 > 0:31:03urea, phosphates - that 5% of the urine is really, really bad stuff,
0:31:03 > 0:31:05which is why you put it on the outside of you.
0:31:05 > 0:31:08OK? So, when someone says, "Do you want to drink my urine?"
0:31:08 > 0:31:11you say no!
0:31:11 > 0:31:14There is only one acceptable way to drink urine
0:31:14 > 0:31:18and that is...
0:31:18 > 0:31:21if you have some special treatment.
0:31:21 > 0:31:25OK? And so this is a special bag
0:31:25 > 0:31:27that recycles urine, OK?
0:31:27 > 0:31:30And what it does, it's a bag within a bag
0:31:30 > 0:31:32and I think I'm going to need another glass here.
0:31:32 > 0:31:35But there's a bag within a bag
0:31:35 > 0:31:37and the bag inside is actually
0:31:37 > 0:31:40a semi-permeable membrane.
0:31:40 > 0:31:44You pee into this red port here,
0:31:44 > 0:31:48the urine goes into the bag, and the bag inside will allow water
0:31:48 > 0:31:51to go through, but not all the nasty stuff.
0:31:51 > 0:31:56Now, to encourage the water across, this green port you put a syrup in
0:31:56 > 0:31:59and the syrup has a very high osmotic pressure,
0:31:59 > 0:32:03lots of molecules that draw the water across
0:32:03 > 0:32:07and you get clean water with all the nasty stuff left outside.
0:32:07 > 0:32:10This, very helpfully, if you can see that there, has a port that says,
0:32:10 > 0:32:13"Dirty water in."
0:32:13 > 0:32:16"Sports syrup in. Clean drink out."
0:32:16 > 0:32:18So, do not drink out of the red port.
0:32:18 > 0:32:20LAUGHTER
0:32:20 > 0:32:25This is one I made earlier, cos osmosis takes a while. And, uh...
0:32:25 > 0:32:27We're going to pour it in here now.
0:32:27 > 0:32:30Here's the thing, because you've got some syrup in there,
0:32:30 > 0:32:34it kind of looks like pee even after it's been reprocessed.
0:32:34 > 0:32:36LAUGHTER
0:32:36 > 0:32:40And...to be honest...
0:32:40 > 0:32:42Do you want to have a smell of that?
0:32:42 > 0:32:45- It smells like...?- Smells...
0:32:45 > 0:32:50- quite a lot like urine.- It smells a lot like pee. Do you want to smell?
0:32:51 > 0:32:55So, it looks a bit like pee and still smells like pee.
0:32:55 > 0:33:00But this is perfectly safe to drink because osmosis has treated it and...
0:33:00 > 0:33:03GIGGLING AND EWS
0:33:05 > 0:33:08To be honest, it really does still... LAUGHTER
0:33:08 > 0:33:10..taste like pee. All right.
0:33:21 > 0:33:26Now, Tim has a much better way of recycling his pee.
0:33:26 > 0:33:28He does recycle it up there.
0:33:28 > 0:33:32Tim Peake and his crew have a really quite cool mechanism which not only
0:33:32 > 0:33:35recycles their urine, but also their sweat
0:33:35 > 0:33:39and the vapour they breathe out of their mouths.
0:33:39 > 0:33:46And they're recycling up to 98% of their body water.
0:33:46 > 0:33:49That's really horrible, that stuff, it's just so horrible.
0:33:49 > 0:33:54That is how you recycle urine. Um...
0:33:54 > 0:33:58But what if you had a way of recycling water, that was also
0:33:58 > 0:34:03a way of recycling your atmosphere, that was also a source of food?
0:34:03 > 0:34:09And I have one of those right here on the shelf. It's called a plant.
0:34:09 > 0:34:10That's what you'd like to do,
0:34:10 > 0:34:13you'd like to take a bunch of plants with you into space.
0:34:13 > 0:34:16But that turns out to be really hard, cos you're in a spaceship
0:34:16 > 0:34:17and there's no natural light
0:34:17 > 0:34:20and there's no soil, cos there's an infection risk from the soil.
0:34:20 > 0:34:23So, how do you grow plants in space?
0:34:23 > 0:34:27I don't know, but I know a man who says he can.
0:34:27 > 0:34:33Let's welcome Alistair from the Royal Horticultural Society.
0:34:45 > 0:34:48Alistair, I'm just going to put this down.
0:34:48 > 0:34:50Now, what's this?
0:34:50 > 0:34:54This is a closed-loop system that will feed us, basically.
0:34:54 > 0:35:00- It produces the food for you to eat. - This is grow-your-own space food?
0:35:00 > 0:35:03- Yeah.- And you can do something with that to make something
0:35:03 > 0:35:06- I would want to eat?- Yeah, yeah. It'd be a bit smaller, but yeah.
0:35:06 > 0:35:12I'm not convinced, but you tell me that I will be, so to show me,
0:35:12 > 0:35:15I'm going to need a volunteer.
0:35:15 > 0:35:18All right. Let's have...
0:35:18 > 0:35:21you. OK, good, all right.
0:35:24 > 0:35:26- What's your name?- Findlay.
0:35:26 > 0:35:28Findlay, you're going to go over here to Christian,
0:35:28 > 0:35:30who's going to help you over there.
0:35:30 > 0:35:33Apparently, you're going to put something together
0:35:33 > 0:35:34that we can grow in space.
0:35:34 > 0:35:38All right. Convince me of this, cos I'm just not buying it.
0:35:38 > 0:35:42So, this is a system that you can grow in space - how is that possible?
0:35:42 > 0:35:43We've got no sunlight in space.
0:35:43 > 0:35:46So, the lights here, you've got red and blue.
0:35:46 > 0:35:50Now, plants photosynthesise at the red and blue lights, so it optimises
0:35:50 > 0:35:54the amount of chlorophyll a and b in relation to efficiency.
0:35:54 > 0:35:56You also have some green lights in there.
0:35:56 > 0:35:58You've got a water system here
0:35:58 > 0:36:02which is a closed water system, because there's near zero gravity.
0:36:02 > 0:36:05Water would be floating out of this at the moment, which is why
0:36:05 > 0:36:07they're completely closed in those systems.
0:36:07 > 0:36:10And so this is a system that could be grown in space
0:36:10 > 0:36:13and I think the guys have tried to do that.
0:36:13 > 0:36:15I think we've got some video of that up here.
0:36:15 > 0:36:19So, this is some weird space plants. What colour are those plants?
0:36:19 > 0:36:22Yeah, so this is the Veggie plant, they're the purple plants.
0:36:22 > 0:36:26- Why are they purple?- That's in relation to the anthocyanins
0:36:26 > 0:36:28that they have in there, so it's the chemistry within those.
0:36:28 > 0:36:32Those are the things that make leaves turn a different colour in autumn.
0:36:32 > 0:36:35- That's right.- OK.- And you can see it's a collapsible system,
0:36:35 > 0:36:39so this is called a Veggie system and leaves sort of come up.
0:36:39 > 0:36:42And what plants have we got here?
0:36:42 > 0:36:46I've heard of five a day, but this is ridiculous. What's this?
0:36:46 > 0:36:50We've got rice here. We've got wheat here.
0:36:50 > 0:36:54We've got basil. We've got soya here.
0:36:54 > 0:36:58We've got tomato here. So, there's a number of crops here
0:36:58 > 0:37:00that we would probably want to take up to space.
0:37:00 > 0:37:03I could see how you could grow this all in space, but what food
0:37:03 > 0:37:05are you going to make with that?
0:37:05 > 0:37:07BELL DINGS Oh.
0:37:08 > 0:37:11Findlay, what's going on?
0:37:11 > 0:37:13We're trying to grow space food here
0:37:13 > 0:37:16and you're just mucking around in the kitchen. What's going on?
0:37:16 > 0:37:20- Hopefully pizza.- Hopefully a... You can make a pizza with all that?
0:37:20 > 0:37:24Oh, yeah, you can make cheese out of soya. Space pizza.
0:37:24 > 0:37:29Christian, let's see some space pizza in your special space-age oven.
0:37:29 > 0:37:32Ladies and gentlemen, space pizza.
0:37:36 > 0:37:40I think you need a bit more basil on there. Findlay, come and grab
0:37:40 > 0:37:41some of this. There you go,
0:37:41 > 0:37:45go and sprinkle that on, off of our hydroponic system.
0:37:45 > 0:37:47Who's the hungriest cameraman?
0:37:47 > 0:37:50It always looks like Joe. Let's feed Joe.
0:37:50 > 0:37:54Let's make sure that Joe can... LAUGHTER
0:37:54 > 0:37:58You just carry on with that, Joe, while we carry on with the programme.
0:37:58 > 0:38:02Alistair, Findlay, thank you so much, great to see you. Thank you.
0:38:10 > 0:38:15OK, so even if we master the art of bringing our life support with us
0:38:15 > 0:38:19in some sort of form that we can regenerate,
0:38:19 > 0:38:21we've still got other problems.
0:38:21 > 0:38:25And that's part of the mission of Tim Peake's crew aboard the ISS.
0:38:25 > 0:38:30So, let's go back to that emergency spacewalk that Tim's crew had to do
0:38:30 > 0:38:32at the start of his mission.
0:38:33 > 0:38:37Astronaut Dan Tani is going to talk us through what is possibly
0:38:37 > 0:38:41the most dangerous thing that any astronaut ever has to do.
0:38:41 > 0:38:44Dan, why are they having to do this spacewalk?
0:38:44 > 0:38:47Cos this wasn't expected, this wasn't in the plans for Tim.
0:38:47 > 0:38:49He wasn't expecting to get up onto the space station
0:38:49 > 0:38:53- and almost immediately have to help supervise a spacewalk.- Absolutely.
0:38:53 > 0:38:57They were doing a routine move of what's call the mobile transporter.
0:38:57 > 0:39:01The mobile transporter is like this trolley that goes back and forth...
0:39:01 > 0:39:04- We can see it here. - Yeah, let's talk about that.
0:39:04 > 0:39:07And so they were doing a routine manoeuvre from one work site
0:39:07 > 0:39:10to another and, unexpectedly, it got stuck.
0:39:10 > 0:39:12It had to release from one work site
0:39:12 > 0:39:15and it got stuck before it could get to the other work site.
0:39:15 > 0:39:18- And they don't know why.- And that's a big deal because they depend
0:39:18 > 0:39:21- very heavily on that arm. - It's a very big deal
0:39:21 > 0:39:26because two of the supply ships that bring cargo to the space station -
0:39:26 > 0:39:31the food, experiments, sometimes oxygen and critical things -
0:39:31 > 0:39:35are grappled by that arm, and right now, that arm is completely useless.
0:39:35 > 0:39:39It's not hooked up to the space station and so they need to get that
0:39:39 > 0:39:43mobile transporter locked into place so the arm can be operated.
0:39:43 > 0:39:46- Going out the lock there. - Yeah, here they go.
0:39:48 > 0:39:51If they are unsuccessful at performing this EVA,
0:39:51 > 0:39:53it will put a halt to everything on the space station.
0:39:53 > 0:39:56They have got to fix this mobile transporter.
0:39:56 > 0:39:59They cannot continue operating the space station
0:39:59 > 0:40:02with the mobile transporter in this position.
0:40:02 > 0:40:03This is a helmet camera.
0:40:03 > 0:40:07We can see their perspective of what they're doing.
0:40:07 > 0:40:11'I'm going to start heading in that direction.'
0:40:11 > 0:40:13So, they're navigating their way to their destination
0:40:13 > 0:40:16and that's what they're doing now, hand over hand,
0:40:16 > 0:40:19working their way around the structure, out that airlock
0:40:19 > 0:40:23and out towards the CETA cart, this transporter we've been hearing about.
0:40:23 > 0:40:29The space station is so large, there are labels out here with arrows
0:40:29 > 0:40:32that say "Airlock", so that you know how to get home.
0:40:32 > 0:40:34We'll see those.
0:40:34 > 0:40:37Because the last thing you want is to be so disorientated, like,
0:40:37 > 0:40:39"I'm not sure where I'm going."
0:40:39 > 0:40:42And we have, basically, how-to-get-home arrows out there.
0:40:42 > 0:40:45Is it easy to get lost on the outside?
0:40:45 > 0:40:49It's very surprisingly easy to lose your orientation
0:40:49 > 0:40:54and not be sure, "Am I on top? Am I on bottom? Am I behind?"
0:40:54 > 0:40:57Especially if it's dark and all you see are a couple of handrails.
0:40:57 > 0:41:00Right, and that's a good point to make, cos right now,
0:41:00 > 0:41:04they're in sunlight. They time the walk to start with an ISS sunrise
0:41:04 > 0:41:07and then they've got 45 minutes before the sun goes down
0:41:07 > 0:41:10and this view will go dark and only be illuminated by their...
0:41:10 > 0:41:13Helmet lights. There are a few external lights
0:41:13 > 0:41:15on the space station.
0:41:15 > 0:41:17Let's have a listen to the downlink, if we can hear it.
0:41:17 > 0:41:19'..on the starboard CETA cart.
0:41:19 > 0:41:23'We'll initiate the release of the brake handle
0:41:23 > 0:41:27'which is believed on the starboard CETA cart to be the suspect
0:41:27 > 0:41:31'that is preventing the movement of the mobile transporter.'
0:41:31 > 0:41:35- 'It's started moving forward now.' - 'OK, we copy that.'
0:41:35 > 0:41:37So, they are at their destination.
0:41:37 > 0:41:39They're there, yeah, they're working it.
0:41:39 > 0:41:42What they want to do is make sure the brake is the problem
0:41:42 > 0:41:45and there's no other problem.
0:41:47 > 0:41:52INDISTINCT TECHNICAL CHATTER
0:41:52 > 0:41:55'OK, copy that. Then you can go ahead and translate up to face one
0:41:55 > 0:42:00'and you're looking for handrail 35-23, which is in bay 02,
0:42:00 > 0:42:02'for your green hook.'
0:42:02 > 0:42:04So, that's a very specific instruction.
0:42:04 > 0:42:07Not just "the handrail" - a numbered handrail and telling him
0:42:07 > 0:42:10where he's going to find it. How useful is that information to you
0:42:10 > 0:42:12- when you're walking?- It's critical.
0:42:12 > 0:42:15They're instructing him to go to that handrail
0:42:15 > 0:42:17and take his safety tether
0:42:17 > 0:42:21and attach it to that handrail, because in the whole choreography,
0:42:21 > 0:42:23they don't want to cross their tethers
0:42:23 > 0:42:25or get it caught up in anything else.
0:42:25 > 0:42:28Right now, Tim Peake is still in the vehicle.
0:42:28 > 0:42:30I guess he's monitoring their progress.
0:42:30 > 0:42:32He's certainly monitoring what's going on,
0:42:32 > 0:42:34making sure he understands where everybody is,
0:42:34 > 0:42:37but he has to be acutely aware of what's happening on the outside
0:42:37 > 0:42:40so that if anything happens, he's ready to jump into action
0:42:40 > 0:42:43and receive them in the airlock.
0:42:43 > 0:42:46- It sounds like they might just be about to get this cart moving.- Yeah.
0:42:46 > 0:42:48Done everything they need to do in the CETA cart
0:42:48 > 0:42:51and it sounds like they're giving the go and getting out of the way.
0:42:51 > 0:42:53They're getting out the way
0:42:53 > 0:42:56so that Mission Control can move that cart automatically from the ground.
0:42:56 > 0:42:59An instruction's going to be issued from Mission Control and get that
0:42:59 > 0:43:02cart moving and we're going to see that in the next couple of minutes.
0:43:02 > 0:43:06'OK, I'm ready for motion whenever Tim and you guys are.'
0:43:06 > 0:43:08'I'm ready for motion, too.'
0:43:10 > 0:43:13'OK, we're putting in the last command.'
0:43:14 > 0:43:18- 'I see motion.'- We do see motion on the mobile transporter.
0:43:18 > 0:43:22'We see motion down here as well, that's good.'
0:43:22 > 0:43:27- Inching towards its destination. - Very slowly.
0:43:27 > 0:43:29'OK, guys, good news, it appears to have reached
0:43:29 > 0:43:34- 'the work site centre, so we are a go to continue.'- It's a big success.
0:43:34 > 0:43:38They couldn't be happier how things went on the spacewalk.
0:43:38 > 0:43:41INDISTINCT RADIO CHATTER
0:43:41 > 0:43:44- 'I'm going to tell you to stop there for a second.'- 'OK.'
0:43:44 > 0:43:47- 'Right when you get to that trunnion pin.'- 'OK, will do.'
0:43:47 > 0:43:51He's taking a picture of Tim Kopra, that's what he's doing.
0:43:51 > 0:43:54He saw a good picture, so he's setting up a picture.
0:43:54 > 0:43:57- So, enough time for selfies. - Right, yeah.
0:43:57 > 0:44:00I think they're doing pretty well. It is remarkable.
0:44:00 > 0:44:02The crew have gone out the airlock,
0:44:02 > 0:44:05got onto the bit of the space station that was broken,
0:44:05 > 0:44:08they have got that brake off, they've moved into place,
0:44:08 > 0:44:11tiny fingers crossed to make sure that that couples into the power
0:44:11 > 0:44:14so they can move it again.
0:44:14 > 0:44:18But I think they have literally saved this mission.
0:44:18 > 0:44:21- I think it's a round of applause for them.- I believe they have.
0:44:21 > 0:44:23APPLAUSE
0:44:32 > 0:44:36Exciting stuff, but only 15 people have ever flown for more than
0:44:36 > 0:44:40200 consecutive days in space. Two of them are in orbit right now.
0:44:40 > 0:44:43One of them is Scott Kelly, the guy on the right in this picture,
0:44:43 > 0:44:47and he's trying to work out the effects of space on the human body
0:44:47 > 0:44:50to prepare us for that next great leap into space.
0:44:50 > 0:44:52And he's pretty good in space.
0:44:52 > 0:44:57You can see he's very comfortable, but he...
0:44:57 > 0:45:02He's still trying to find out how to survive for longer and longer.
0:45:02 > 0:45:05That's the goal of this one-year mission.
0:45:05 > 0:45:08Right there you can see him on the space gym.
0:45:08 > 0:45:11He has to spend a couple of hours a day on that just to preserve
0:45:11 > 0:45:13his muscle and bone and his heart,
0:45:13 > 0:45:18cos otherwise he comes back like a big, fat couch potato.
0:45:18 > 0:45:22And the problems you have because of weightlessness you can avoid
0:45:22 > 0:45:27if you do with gravity what we do with our light, heat,
0:45:27 > 0:45:30sources of power, drink and food,
0:45:30 > 0:45:34and that is take gravity with you.
0:45:34 > 0:45:39Now, that's not as sci-fi as it sounds. That's easier said than done.
0:45:39 > 0:45:44All you need to do is make use of a bit of circular motion,
0:45:44 > 0:45:49a bit of centripetal acceleration and a bit of centrifugal force.
0:45:49 > 0:45:52We've got four astronauts on this mission. Are you nervous?
0:45:52 > 0:45:54AUDIENCE MUTTERS
0:45:54 > 0:45:56No? You really, really should be.
0:45:56 > 0:45:59This didn't go well in rehearsals. Here we go.
0:45:59 > 0:46:02And...there we go on our space mission!
0:46:04 > 0:46:07Oh, my gosh. OK, whoa!
0:46:13 > 0:46:18So, that was another partial success. But you get the point.
0:46:18 > 0:46:21If you can spin something fast enough and hard enough, you can create...
0:46:21 > 0:46:24it's not artificial gravity, really, actually.
0:46:24 > 0:46:29This is acceleration. Acceleration and gravity are equivalent.
0:46:29 > 0:46:32So, this is gravity, really,
0:46:32 > 0:46:36in a sense, when we spin the vehicle. But here's the problem -
0:46:36 > 0:46:39to get a lot of gravity, if your circle is small,
0:46:39 > 0:46:42you need to spin very, very fast.
0:46:42 > 0:46:46The only way of producing adequate gravity and not spinning fast
0:46:46 > 0:46:51and not making yourself horribly dizzy is to spin something big.
0:46:51 > 0:46:54Now, bizarrely, Nasa have done those experiments.
0:46:54 > 0:46:58On the screen we can see some experiments, and while we get
0:46:58 > 0:47:02this mess cleaned up, we can see... I think this is from the 1960s.
0:47:02 > 0:47:07This is Nasa trying to work out how big a radius
0:47:07 > 0:47:10and how fast you can spin people to get them to tolerate
0:47:10 > 0:47:15rotational vehicles so that you can create artificial gravity.
0:47:15 > 0:47:18This guy's being suspended by the crane above him on his side
0:47:18 > 0:47:21and he's walking around this rotating structure.
0:47:21 > 0:47:24What they found when they did lots of these experiments
0:47:24 > 0:47:28is that everyone gets dizzy at a point, but some people...
0:47:28 > 0:47:33There are some rates of rotation that everyone can manage to cope with.
0:47:35 > 0:47:38And that rate of rotation is four revolutions per minute.
0:47:38 > 0:47:42No matter how bad you are on a fairground ride,
0:47:42 > 0:47:44after a certain amount of time, you can all manage
0:47:44 > 0:47:46four revolutions per minute.
0:47:46 > 0:47:50So, if that's your limiting factor, if you have to spin the vehicle
0:47:50 > 0:47:54at four revolutions a minute and you want to make one G of load
0:47:54 > 0:47:58in that vehicle, then how big does your vehicle need to be?
0:47:58 > 0:48:02I'm going to save you the maths here, because the answer is
0:48:02 > 0:48:06a vehicle with a rotating radius of about 62.5 metres.
0:48:06 > 0:48:08Now, how big is that?
0:48:08 > 0:48:12It is actually exactly the same size - almost the same size -
0:48:12 > 0:48:16as the London Eye. Now, who's ever ridden in the London Eye?
0:48:16 > 0:48:18OK. It does not go round four times a minute.
0:48:18 > 0:48:21If you're on it and it goes round four times a minute,
0:48:21 > 0:48:23try and get off cos it's going wrong. LAUGHTER
0:48:23 > 0:48:26But we can make it turn at four revolutions a minute
0:48:26 > 0:48:30and that's what it looks like going round at four revolutions per minute.
0:48:30 > 0:48:33All the people on it that day wanted their money back.
0:48:33 > 0:48:35But if this was your space vehicle going through space,
0:48:35 > 0:48:37turning at that sort of rate,
0:48:37 > 0:48:39then the people in the pods wouldn't be standing on the floors,
0:48:39 > 0:48:41they'd be on the edges,
0:48:41 > 0:48:44being able to stand up, because there would be one G of load.
0:48:44 > 0:48:48One G is the force of gravity we have on Earth, that's great.
0:48:48 > 0:48:52But that London Eye is as big across as the space station is long.
0:48:52 > 0:48:56And it takes a lot of effort to build that. Took 15 years
0:48:56 > 0:48:59to build the space station, and sending vehicles like that to Mars
0:48:59 > 0:49:02is a huge, huge engineering challenge.
0:49:02 > 0:49:05So, what other option do you have?
0:49:05 > 0:49:09Well, when I worked for Nasa in 2007,
0:49:09 > 0:49:11I was part of an experiment to answer that question.
0:49:11 > 0:49:15And we thought, "What if you could get a centrifuge that you could fit
0:49:15 > 0:49:17"inside an ordinary vehicle?"
0:49:17 > 0:49:20So, inside a module that looks rather like that.
0:49:20 > 0:49:23As big as that that you could send up to space on an ordinary rocket.
0:49:23 > 0:49:28And you could spin something quite fast to generate artificial gravity.
0:49:28 > 0:49:31And you can do that, you can get a centrifuge that would almost fit
0:49:31 > 0:49:34on the floor here, and I think we've got some footage of that.
0:49:34 > 0:49:37This is the Short Radius Centrifuge in Houston.
0:49:37 > 0:49:39That is my former mentor at Nasa,
0:49:39 > 0:49:43now the Director of Life Sciences at Johnson Space Center.
0:49:43 > 0:49:46He's got his eyes closed cos I don't think he liked being on it very much.
0:49:46 > 0:49:51Now, you say, that's going to be rubbish, flying to Mars,
0:49:51 > 0:49:53spinning on that all day.
0:49:53 > 0:49:56But here's the kicker - you don't have to spin on it all day.
0:49:56 > 0:50:00If you spin really fast, fast enough to give you more than one G of load,
0:50:00 > 0:50:05then you can give gravity like you would give the dose of a drug.
0:50:05 > 0:50:08And you can take that gravity dose twice a day
0:50:08 > 0:50:12for one hour in the morning, one hour in the afternoon,
0:50:12 > 0:50:16and that is enough to provide quite a lot of protection.
0:50:16 > 0:50:22The absence of gravity which has been your enemy all along isn't a problem.
0:50:22 > 0:50:25Actually, when gravity returns, it is your enemy.
0:50:25 > 0:50:32And to get safely onto the surface of Mars, you need to be able to stop.
0:50:32 > 0:50:36And there's one thing that rocket scientists will tell you
0:50:36 > 0:50:39and that is that the hardest two things in all of rocket science
0:50:39 > 0:50:42are starting and stopping again.
0:50:42 > 0:50:47And so I thought we should bring on an expert in stopping
0:50:47 > 0:50:49when you get to Mars.
0:50:49 > 0:50:54So, it's my great, great pleasure to welcome our very special guest...
0:50:54 > 0:50:59an engineer from the Jet Propulsion Laboratory in Pasadena
0:50:59 > 0:51:04and one of the lead engineers on the Mars Curiosity Rover,
0:51:04 > 0:51:07Dr Anita Sengupta.
0:51:15 > 0:51:19Now, Anita... Come and give us a hand here, you two.
0:51:19 > 0:51:21Come and give us a hand to stretch this out.
0:51:21 > 0:51:25- What have you got here? - This is a disk-gap-band parachute
0:51:25 > 0:51:28and it's specially used on Mars and the reason for that is, on Mars,
0:51:28 > 0:51:32when you enter the atmosphere, you're coming at very fast speeds,
0:51:32 > 0:51:33and when you deploy the parachute,
0:51:33 > 0:51:36you're coming in at supersonic speeds.
0:51:36 > 0:51:39I'm experiencing all sorts of dynamic instability here.
0:51:39 > 0:51:43- Have we got a working version of this?- We do, actually.
0:51:43 > 0:51:45We have one which is a subscale version.
0:51:45 > 0:51:48Represents about 3% of the scale that we used on Mars
0:51:48 > 0:51:49which we can show you now.
0:51:49 > 0:51:53We're going to count in and then release the parachute.
0:51:53 > 0:51:57Ready, everyone? Three, two, one.
0:51:59 > 0:52:00There it goes.
0:52:08 > 0:52:10- So, that is very impressive.- It is.
0:52:10 > 0:52:13It's very lightweight and so what's so unique about these parachutes
0:52:13 > 0:52:16is they weigh almost nothing, but they're incredibly strong.
0:52:16 > 0:52:18For reference, the parachute that we used for Curiosity,
0:52:18 > 0:52:20it weighed only about 100lbs
0:52:20 > 0:52:26but had to withstand a total load on of it about 65,000lbs of force.
0:52:26 > 0:52:31I love that. It's a very interesting design, but I still don't get...
0:52:31 > 0:52:34What's the fuss with stopping at Mars? We stop at Earth all the time.
0:52:34 > 0:52:39You've got some video here of what it was like to stop at Mars.
0:52:39 > 0:52:41You were one of the lead engineers for this,
0:52:41 > 0:52:44the Mars Curiosity Rover, which was fantastic.
0:52:44 > 0:52:47This is the size of a Volkswagen Beetle coming into Mars' atmosphere.
0:52:47 > 0:52:50- Tell us what's happening here.- At this point we're at hypersonic flow.
0:52:50 > 0:52:54We've slowed down to around 1,000mph and the parachute deploys at mach 2,
0:52:54 > 0:52:57two times the speed of sound, around 900mph.
0:52:57 > 0:52:59It continues to slow down to subsonic speeds.
0:52:59 > 0:53:01At that point, it's actually reached terminal velocity.
0:53:01 > 0:53:04You can't go any slower, so you basically cut the parachute away.
0:53:04 > 0:53:07Then the Rover is in freefall, descending towards the surface.
0:53:07 > 0:53:11At this point, it turns on a total of eight main landing engines,
0:53:11 > 0:53:15eight rockets firing towards the ground to slow it down even further.
0:53:15 > 0:53:17That gets it down to around 200mph.
0:53:17 > 0:53:20As you approach the surface, we start something very unique,
0:53:20 > 0:53:22which is called the Sky Crane manoeuvre.
0:53:22 > 0:53:24This is the first time we've ever done this on Mars.
0:53:24 > 0:53:28We start to lower the Rover on a series of three tethers.
0:53:28 > 0:53:31And the reason we do this is we actually make the Rover
0:53:31 > 0:53:33the actual landing platform.
0:53:33 > 0:53:36And it allows us to have these big, powerful engines firing
0:53:36 > 0:53:39towards the ground, but at a safer distance away from the Rover
0:53:39 > 0:53:42and away from the surface. Those three tethers then cut away.
0:53:42 > 0:53:45That little rocket ship flies off 45 degrees to the side
0:53:45 > 0:53:47and crash-lands - its mission is over.
0:53:47 > 0:53:50And now the Rover is safely on the surface of Mars.
0:53:50 > 0:53:51Wow, that's amazing.
0:53:51 > 0:53:54APPLAUSE
0:53:54 > 0:53:57That is, hands down, the coolest landing I have ever seen.
0:53:57 > 0:54:00But this parachute, why does it have the gap?
0:54:00 > 0:54:03It has the gap because it experiences something called
0:54:03 > 0:54:06a supersonic instability. So, what you saw as it descended
0:54:06 > 0:54:09from the ceiling was actually in subsonic flow.
0:54:09 > 0:54:12In subsonic flow, the parachute is relatively stable,
0:54:12 > 0:54:15but in supersonic flow, things look entirely different.
0:54:15 > 0:54:19And we have a video which actually has the parachute deploying
0:54:19 > 0:54:24at 2.7 mach, which is almost three times the speed of sound.
0:54:24 > 0:54:27What you can see is it collapses and inflates like a jellyfish.
0:54:27 > 0:54:29We don't want it to do that
0:54:29 > 0:54:31but, unfortunately on Mars, that's what it does.
0:54:31 > 0:54:34When it happens, you can actually cause the parachute to produce
0:54:34 > 0:54:36less aerodynamic drag, which is what slows you down.
0:54:36 > 0:54:39It can actually damage the parachute and make it fall apart
0:54:39 > 0:54:42and so we were really concerned about this for the Curiosity Rover,
0:54:42 > 0:54:44cos it was the largest parachute we'd ever built, and it also
0:54:44 > 0:54:47was deploying at the highest mach number we've ever deployed at.
0:54:47 > 0:54:51That is incredible. The gap allows it not to fall apart as it opens.
0:54:51 > 0:54:55This is absolutely fantastic. I'm going to give you your parachute back
0:54:55 > 0:54:57- cos I think you might want to use it again.- Yes.
0:54:57 > 0:54:59Anita Sengupta, everybody.
0:54:59 > 0:55:01APPLAUSE
0:55:06 > 0:55:08So, we can get there in one piece,
0:55:08 > 0:55:13we can stop using one of Anita's incredible systems.
0:55:13 > 0:55:15And then we're there.
0:55:15 > 0:55:19And up on the screen now you can see a picture of one of the places
0:55:19 > 0:55:21on Mars that I would like to visit.
0:55:21 > 0:55:27This is the very beautiful dappled centre of Victoria Crater.
0:55:27 > 0:55:31That crater, it's a real picture, it's 780 metres across.
0:55:31 > 0:55:36It's been visited by the automatic rovers that have been, really,
0:55:36 > 0:55:40the pathfinder missions for our future human exploration
0:55:40 > 0:55:42and we've peered into that crater.
0:55:42 > 0:55:47In its walls are sedimentary rocks, layers and layers of rock
0:55:47 > 0:55:49that tell us about the history of Mars.
0:55:49 > 0:55:53There is still so much left to explore, but we remain confident.
0:55:53 > 0:55:56So much so that we've begun to think about the way
0:55:56 > 0:55:58we would get home from Mars.
0:55:58 > 0:56:03Now, there's a way of lightening your packing load by using
0:56:03 > 0:56:06what you've got all around you on Mars.
0:56:06 > 0:56:09And that's carbon dioxide.
0:56:09 > 0:56:15Mars' atmosphere is about 99% carbon dioxide and you can use that.
0:56:15 > 0:56:19It brings you some very important things - carbon and oxygen.
0:56:19 > 0:56:22If you bring a little bit of hydrogen along with you,
0:56:22 > 0:56:24and it turns out that's quite easy to do,
0:56:24 > 0:56:27then you can make some useful materials with something
0:56:27 > 0:56:30called a Sabatier reaction.
0:56:30 > 0:56:33In a Sabatier reaction you can combine hydrogen
0:56:33 > 0:56:39and carbon dioxide, and the product is methane and oxygen.
0:56:39 > 0:56:42And that is enough to make some rocket fuel.
0:56:42 > 0:56:46You don't usually think of methane as being something that can
0:56:46 > 0:56:50propel people and objects into space, so I'm going to show you.
0:56:50 > 0:56:55Andy, goggle time. And I think front row goggle time. Good, all right.
0:56:55 > 0:56:59I know you think of methane as being a bit of a comedy gas
0:56:59 > 0:57:04that cows fart out but, actually, it can propel rockets.
0:57:04 > 0:57:09Now, Andy's going to light this one because there's a trick to it
0:57:09 > 0:57:11and he says it has a more...
0:57:11 > 0:57:15He technically described it earlier on as a more "flamey flame".
0:57:15 > 0:57:16LAUGHTER
0:57:16 > 0:57:18So, this is methane.
0:57:24 > 0:57:26AUDIENCE GASP
0:57:36 > 0:57:38We are on our way home
0:57:38 > 0:57:44and there's just time for Tim to say a final goodbye.
0:57:44 > 0:57:46So, it's been great talking to everybody
0:57:46 > 0:57:48at the Royal Institute Christmas Lectures
0:57:48 > 0:57:50from the International Space Station.
0:57:50 > 0:57:52I'm sorry I couldn't be with you in person,
0:57:52 > 0:57:55but I certainly think that I've got the most privileged position
0:57:55 > 0:57:57to be here onboard at the moment
0:57:57 > 0:57:59and looking down on the beautiful planet Earth.
0:57:59 > 0:58:03So, to everybody back there, goodbye.
0:58:04 > 0:58:08Thank you all for sharing in Tim's adventure.
0:58:08 > 0:58:12But what you've seen here has been the adventure of our lives.
0:58:12 > 0:58:16These are people who make not just Tim's mission happen
0:58:16 > 0:58:19but all of science happen.
0:58:19 > 0:58:22This has been our adventure.
0:58:22 > 0:58:28And it will be yours and yours and yours and yours and yours.
0:58:28 > 0:58:33This is the adventure of your generation
0:58:33 > 0:58:35and it's time you started it.
0:58:35 > 0:58:37Thank you.