0:00:07 > 0:00:09'Down, I see her. Right cable is down.'
0:00:11 > 0:00:12'OK to go for configuration, Steve.'
0:00:12 > 0:00:13'Thank you, Al.'
0:00:16 > 0:00:22220 miles above the Earth on 12th March 2009,
0:00:22 > 0:00:27was a day like any other on the International Space Station.
0:00:27 > 0:00:29'Two and three stowed.'
0:00:35 > 0:00:38It was mid-morning and I was getting ready to exercise.
0:00:38 > 0:00:43And we were just sort of getting into our mid-morning routine, if you will.
0:00:43 > 0:00:45'OK, Nick. On my way.'
0:00:46 > 0:00:49But then they got an unusual message.
0:00:51 > 0:00:53We got a call that we were having "a red conjunction".
0:00:53 > 0:00:56We were looking around, "What is a red conjunction?"
0:00:56 > 0:00:58Because we hadn't really trained for it.
0:01:01 > 0:01:04A red conjunction is a warning code
0:01:04 > 0:01:08that the space station could be hit by some orbital debris.
0:01:11 > 0:01:12It was a little bit chaotic,
0:01:12 > 0:01:16because this was the first time we had had one of these.
0:01:16 > 0:01:20The space station was travelling at nearly 8km per second.
0:01:21 > 0:01:23The space junk was travelling at the same speed
0:01:23 > 0:01:25in the opposite direction.
0:01:29 > 0:01:33If they hit, the consequences could be catastrophic.
0:01:38 > 0:01:40It gets hit by something relatively small...
0:01:43 > 0:01:45..penetrates, but because of the pressure inside,
0:01:45 > 0:01:49it just forces the modules to open up just like a balloon bursting.
0:01:51 > 0:01:53And that happens extremely quickly,
0:01:53 > 0:01:58with no chance that an astronaut in that module could ever get out.
0:01:58 > 0:02:01'Copy, Al. You're on your way to the station.'
0:02:02 > 0:02:04Nasa was taking no chances
0:02:04 > 0:02:09and scrambled astronaut Sandra Magnus to the Soyuz life raft.
0:02:09 > 0:02:11All she could do then
0:02:11 > 0:02:14was sit and wait.
0:02:16 > 0:02:19And it's either going to hit or it's not going to hit.
0:02:19 > 0:02:22And so worrying about it doesn't help you.
0:02:27 > 0:02:30Was this just an isolated incident
0:02:30 > 0:02:34or was it a sign of a growing threat to life in space...
0:02:36 > 0:02:39..and modern life on Earth?
0:02:57 > 0:02:59'And liftoff.'
0:03:02 > 0:03:05'First stage move. Propulsion performing normally.'
0:03:14 > 0:03:16Space...
0:03:18 > 0:03:20..endless and empty.
0:03:21 > 0:03:23At least that's what we used to think.
0:03:26 > 0:03:28In the last few decades,
0:03:28 > 0:03:31orbits around Earth have become crowded with satellites
0:03:31 > 0:03:34and littered with space junk.
0:03:37 > 0:03:40So space junk is all the stuff that we've launched into orbit
0:03:40 > 0:03:43that no longer serves a useful purpose.
0:03:43 > 0:03:46So it's satellites, it's rocket bodies,
0:03:46 > 0:03:47it's, you know, old gloves.
0:03:47 > 0:03:51It's toolkits that astronauts have accidentally dropped.
0:03:53 > 0:03:57Basically, litter that we've left in space.
0:04:05 > 0:04:10But littering space is much more dangerous than it is on Earth.
0:04:11 > 0:04:14Those objects are going at 17,000 miles an hour.
0:04:14 > 0:04:16And when you're going 17,000 miles an hour,
0:04:16 > 0:04:20it does not take a big piece of debris to ruin your day.
0:04:30 > 0:04:35Satellites are virtually defenceless against high-speed orbital debris.
0:04:39 > 0:04:43And they are crucial to modern life on Earth.
0:04:46 > 0:04:51We are far more connected and far more dependent upon satellites
0:04:51 > 0:04:53than most people really know.
0:04:55 > 0:04:56The ability to make phone calls,
0:04:56 > 0:05:01the way we do it now was just a dream less than 100 years ago.
0:05:02 > 0:05:05We're all connected to the internet.
0:05:05 > 0:05:07Weather satellites, navigation systems,
0:05:07 > 0:05:09it's almost impossible to get lost,
0:05:09 > 0:05:14despite what the guidance says on the GPS about turn left and turn right.
0:05:17 > 0:05:22All of that and more is becoming increasingly vulnerable.
0:05:23 > 0:05:25Unless we tackle the debris problem,
0:05:25 > 0:05:27there is going to be no weather forecast,
0:05:27 > 0:05:30there is going to be no news story from the other side of the world.
0:05:30 > 0:05:33You're not going to be able to turn on the television and see the World Cup.
0:05:42 > 0:05:46But how did space become littered with dangerous debris?
0:05:49 > 0:05:51'Today, a new moon is in the sky.
0:05:51 > 0:05:55'A 23-inch metal spear placed in orbit by a Russian rocket.'
0:05:56 > 0:05:59Space was a pristine environment,
0:05:59 > 0:06:02until the launch of Sputnik in 1957.
0:06:06 > 0:06:09But in the first decades of spaceflight,
0:06:09 > 0:06:12every time a rocket or satellite was launched,
0:06:12 > 0:06:14it left behind some debris.
0:06:32 > 0:06:36No-one thought it was much of a problem until this man,
0:06:36 > 0:06:39Donald Kessler, did some calculations.
0:06:40 > 0:06:44He was working for Nasa in the late '60s and early '70s,
0:06:44 > 0:06:47when he discovered that leaving junk in orbit
0:06:47 > 0:06:49wasn't like dumping junk on Earth.
0:06:52 > 0:06:55People tend to think of orbit like a road through space.
0:06:55 > 0:06:58I mean, as long as you stay on your road, you're not going to get hit.
0:06:58 > 0:07:02It would be more accurate to think of the Earth as being
0:07:02 > 0:07:04one big paved planet.
0:07:04 > 0:07:06And when you want to go someplace,
0:07:06 > 0:07:09you drive in a straight line from one place to another
0:07:09 > 0:07:14and, of course, with no stop lights and no place to stop
0:07:14 > 0:07:17and you're going to be running into each other in all kinds of directions.
0:07:17 > 0:07:20And that's exactly what you've got in orbit.
0:07:20 > 0:07:24So I headed up with an equation where I could write the spatial density,
0:07:24 > 0:07:26its apogee and inclination.
0:07:26 > 0:07:28Then you can do neat things like...
0:07:28 > 0:07:30His calculations predicted that,
0:07:30 > 0:07:35if bits of junk started smashing into each other at such huge speeds...
0:07:35 > 0:07:39If you want to know the flux, the spatial density...
0:07:39 > 0:07:41..they'd create a cascade of collisions
0:07:41 > 0:07:44that would litter orbits with dangerous debris.
0:07:44 > 0:07:46The integral of S squared...
0:07:46 > 0:07:49This became known as the Kessler Syndrome.
0:07:50 > 0:07:52..integrated over the volume.
0:07:55 > 0:07:58In other words, if you never launch anything else in space,
0:07:58 > 0:08:03there will still be this cascading phenomena that continues to grow
0:08:03 > 0:08:08and, actually, it continues until you essentially grind up all the satellites into small dust particles.
0:08:17 > 0:08:19Three passed SV and 26.
0:08:19 > 0:08:20No time critical commanding.
0:08:20 > 0:08:23No satellite conjunctions. Good on step six.
0:08:23 > 0:08:27All data feeds to externals are open and both communication lines to the site are good.
0:08:27 > 0:08:29No applicable sieves or TPs. You're good to execute.
0:08:29 > 0:08:31Copy that, ma'am.
0:08:33 > 0:08:37The prospect of this nightmare scenario was so worrying that,
0:08:37 > 0:08:38in the early '80s,
0:08:38 > 0:08:42the American Air Force started cataloguing space junk.
0:08:44 > 0:08:47The technology only allowed them to track objects
0:08:47 > 0:08:49slightly bigger than a cricket ball.
0:08:49 > 0:08:53Give level one a call on the TTC-56.
0:08:54 > 0:08:58They started at 6,000 pieces.
0:08:58 > 0:09:03And that number grew slowly to 10,000 over the next two decades,
0:09:03 > 0:09:07helped by an international agreement calling for used rocket bodies
0:09:07 > 0:09:12to be returned to Earth and burned up in the upper atmosphere.
0:09:12 > 0:09:13OK, stand by.
0:09:17 > 0:09:21It kept the risk of any major collision very low.
0:09:22 > 0:09:24But in 2007,
0:09:24 > 0:09:26all that changed.
0:09:28 > 0:09:30The Chinese launched a missile
0:09:30 > 0:09:33that took out one of their own defunct old satellites
0:09:33 > 0:09:35in low Earth orbit.
0:09:37 > 0:09:42The American military were under no illusions about what this meant.
0:09:43 > 0:09:45Well, I think they did that because they realised
0:09:45 > 0:09:48that the United States military
0:09:48 > 0:09:50is critically dependent on space.
0:09:50 > 0:09:54And they felt like if they were going to be able
0:09:54 > 0:09:58to effectively respond to whatever challenges they had in the future,
0:09:58 > 0:10:01they needed to develop a way to challenge our space capabilities.
0:10:02 > 0:10:04Basically, there's not a single military operation
0:10:04 > 0:10:06that takes place in the world today
0:10:06 > 0:10:08that is not critically dependent on space capabilities.
0:10:08 > 0:10:10And if space goes away,
0:10:10 > 0:10:12we do not fight as effectively as we would otherwise.
0:10:15 > 0:10:18As Kessler predicted,
0:10:18 > 0:10:21collisions in space are more dangerous than those on the ground.
0:10:23 > 0:10:26As demonstrated in this computer model.
0:10:29 > 0:10:33After the collision, you see quite a compact debris cloud at the start.
0:10:33 > 0:10:36But then, because some of the fragments are thrown into higher orbits
0:10:36 > 0:10:39and some are thrown into lower orbits, the speed is different.
0:10:39 > 0:10:43So you see the debris clouds stretch out and it forms this ring.
0:10:43 > 0:10:46Now, because the Earth is not spherical,
0:10:46 > 0:10:50it causes that debris ring to start to stretch out.
0:10:50 > 0:10:53It moves the orbits around the planet.
0:10:53 > 0:10:56So it goes from this kind of compact debris cloud right at the start
0:10:56 > 0:10:59to the situation where all of that debris
0:10:59 > 0:11:03ends up being distributed all the way around the planet.
0:11:05 > 0:11:07Before China took out its old satellite,
0:11:07 > 0:11:11the American Air Force were tracking 10,000 objects
0:11:11 > 0:11:12in their debris catalogue.
0:11:14 > 0:11:18After it, they were tracking an extra 3,000.
0:11:20 > 0:11:22The debris field collisions create
0:11:22 > 0:11:25is a massive concern for the general
0:11:25 > 0:11:28who is in charge of all of America's space operations.
0:11:29 > 0:11:34If you go to war in space, then it becomes a kinetic war.
0:11:34 > 0:11:36You create a debris field that is just unmanageable
0:11:36 > 0:11:38and you can't operate or fly in it.
0:11:38 > 0:11:41So I hope to never go to war in space.
0:11:41 > 0:11:44But at the same time, if we're threatened,
0:11:44 > 0:11:45we have to be able to defend ourselves
0:11:45 > 0:11:48and we have to be able to defend ourselves right now.
0:11:53 > 0:11:57But the debris problem got worse in 2009
0:11:57 > 0:11:59when an Iridium satellite collided
0:11:59 > 0:12:03with an out-of-control Russian Kosmos satellite.
0:12:05 > 0:12:09Now they were monitoring 17,000 pieces of junk.
0:12:11 > 0:12:14At that number, Kessler's calculations
0:12:14 > 0:12:18were forecasting a major collision on average every five years.
0:12:19 > 0:12:23And really the situation you start to worry about is that's just one event.
0:12:23 > 0:12:25You know, if you start to say,
0:12:25 > 0:12:28"We're going to have one of these events every five years
0:12:28 > 0:12:31"and that each one is going to generate thousands of fragments,"
0:12:31 > 0:12:36then you end up in the situation where it's basically, you know, a lottery,
0:12:36 > 0:12:39in terms of whether or not your satellite is going to be hit.
0:12:39 > 0:12:44We see thousands and thousands of near misses every single day
0:12:44 > 0:12:47as a result of all the junk that we've put up there.
0:12:51 > 0:12:54But that average of one collision every five years
0:12:54 > 0:12:57might not be much of a guide to what happens in the future.
0:12:59 > 0:13:02So let's say that you're on a soccer team
0:13:02 > 0:13:06and your average is one goal per game.
0:13:06 > 0:13:09A 20-game season, you score 20 goals
0:13:09 > 0:13:12because you've scored one goal a game.
0:13:12 > 0:13:15So, of course, you're very reliable.
0:13:15 > 0:13:20However, you could just as well have scored ten goals in two games
0:13:20 > 0:13:23and were useless the other 18 games.
0:13:23 > 0:13:24Your average is the same,
0:13:24 > 0:13:29but the confidence that I have of what you're going to do the next game is going to be much lower.
0:13:29 > 0:13:32I don't know whether or not you're going to have a ten-goal game
0:13:32 > 0:13:34or a zero-goal game.
0:13:34 > 0:13:36The same problem right now having to do with space.
0:13:36 > 0:13:38We know the average.
0:13:38 > 0:13:40We don't know if the next event's going to occur
0:13:40 > 0:13:42in one day or one decade.
0:13:44 > 0:13:46So the stakes couldn't be higher.
0:13:46 > 0:13:48But until last year,
0:13:48 > 0:13:52no-one knew exactly what happened to spacecraft when they collided.
0:13:53 > 0:13:55Until this...
0:14:03 > 0:14:05This is the work of Patti Scheaffer.
0:14:08 > 0:14:12She's a key part of the team that fired a baked bean can-sized object
0:14:12 > 0:14:16into a tank roughly the same size as the upper stage of a rocket.
0:14:20 > 0:14:23And size mattered.
0:14:25 > 0:14:27Well, this was the size of the object.
0:14:27 > 0:14:29It was maybe a little bit shorter
0:14:29 > 0:14:31but, basically, a large hollow object
0:14:31 > 0:14:34is more representative of something that's actually in space,
0:14:34 > 0:14:38like maybe a small satellite or a piece of a small satellite.
0:14:38 > 0:14:41It also had to be a full-scale test.
0:14:41 > 0:14:46Lots of people fire things like that, for instance,
0:14:46 > 0:14:48and many things, many physical phenomenon
0:14:48 > 0:14:53do not scale with size very well.
0:14:53 > 0:14:56So we really wanted to get a full-scale, full-sized test.
0:14:59 > 0:15:03It was the culmination of years of work.
0:15:03 > 0:15:06But it was over in a flash.
0:15:06 > 0:15:07"Is that T minus ten?"
0:15:07 > 0:15:09"Yes, that's T minus ten."
0:15:09 > 0:15:12"Nine, eight..." And then you hear this...
0:15:13 > 0:15:15And the building literally shakes a little bit.
0:15:15 > 0:15:19But I think a lot of it is me, you know, just being freaked out.
0:15:20 > 0:15:23And then you see your screen flash up and it's over.
0:15:24 > 0:15:26All that work is turned into this.
0:15:30 > 0:15:32Travelling at 7km per second...
0:15:34 > 0:15:36the can made a huge mess.
0:15:41 > 0:15:47So this piece of modern art here is what the tank looks like.
0:15:47 > 0:15:49Now, this was the top of the tank.
0:15:49 > 0:15:52Right here, it folded after it flew through the inside.
0:15:52 > 0:15:54But you can see it's all splayed out.
0:15:55 > 0:16:01The intense heat from the explosion vaporised huge chunks of metal.
0:16:01 > 0:16:05And when it condensed and cooled, she made a startling new discovery.
0:16:06 > 0:16:11Flakes of aluminium, which came from bits of the can and the tank.
0:16:12 > 0:16:17They might look benign, but in space they'd be lethal.
0:16:19 > 0:16:21Now that's about, er...
0:16:21 > 0:16:23What is that? 250 milligrams.
0:16:23 > 0:16:28That's a little bit bigger, heavier than a ibuprofen pill.
0:16:28 > 0:16:31And the energy that would have on orbit
0:16:31 > 0:16:35at, say, 14km per second would be, er...
0:16:36 > 0:16:38Well, the momentum would be about the same
0:16:38 > 0:16:41as a hot-loaded .357 Magnum.
0:16:41 > 0:16:43So that's a lot of momentum.
0:16:43 > 0:16:44And the energy would be more like
0:16:44 > 0:16:48a .50-calibre Browning machine gun sniper round.
0:16:48 > 0:16:52So if you're going to think about how dangerous this is on orbit,
0:16:52 > 0:16:55think .357 Magnum, .50-calibre sniper round.
0:16:55 > 0:16:56Somewhere in there.
0:17:09 > 0:17:12And she discovered that the collision generated
0:17:12 > 0:17:13hundreds of these flakes.
0:17:17 > 0:17:21No-one knew that vaporised metal could be so dangerous.
0:17:27 > 0:17:31So if there are many more particles produced than we thought,
0:17:31 > 0:17:3410 times, 100 times, 1,000 times more,
0:17:34 > 0:17:36then it has a snowball effect,
0:17:36 > 0:17:38because each one of those particles,
0:17:38 > 0:17:41if there's ten times more, there could be ten times more strikes.
0:17:41 > 0:17:45And each one of those makes ten, so that's ten times ten, which is 100.
0:17:45 > 0:17:49If there's 100 times more, then each one of those can make strikes,
0:17:49 > 0:17:51which is 100 times 100, which is 10,000.
0:17:51 > 0:17:53So it snowballs rapidly.
0:17:53 > 0:17:56The question is, how rapidly is it going to snowball?
0:17:56 > 0:17:58And the only way we can know that
0:17:58 > 0:18:00is to know how many of these particles we can't see
0:18:00 > 0:18:01are actually made.
0:18:12 > 0:18:17But if there are more objects in orbit than previously thought,
0:18:17 > 0:18:19there should be more bullet-sized holes
0:18:19 > 0:18:21in the biggest thing up there...
0:18:23 > 0:18:26..the space station.
0:18:26 > 0:18:30'The thing we showed you is still in the socket caddy when you get there.'
0:18:30 > 0:18:33'It'll be right of the front module. It'll be right of the front module.'
0:18:33 > 0:18:37'You can see almost everything from that vantage point.'
0:18:37 > 0:18:40Astronaut Jim Reilly was on a spacewalk
0:18:40 > 0:18:44to repair an external radiator on the station
0:18:44 > 0:18:47when he spotted something he had never seen before.
0:18:49 > 0:18:52And as we're tilting back, we're going past this radiator.
0:18:52 > 0:18:53I noticed right out on the end of it,
0:18:53 > 0:18:56there were three what looked like bullet holes
0:18:56 > 0:18:59about the size of a 7.62 millimetre round.
0:18:59 > 0:19:04And it's about the size of my thumb. Three of them, just about that size.
0:19:04 > 0:19:07There was a fourth hole on the flight immediately behind mine.
0:19:07 > 0:19:10A fellow named Rick Mastracchio was working on the same area.
0:19:10 > 0:19:13And down by Rick, there's a fourth bullet hole on there.
0:19:15 > 0:19:19The space station can absorb hits from small pieces of junk
0:19:19 > 0:19:22because it has a specially constructed hull
0:19:22 > 0:19:27made up of an ingenious layering system called a Whipple shield.
0:19:29 > 0:19:33What you see here is a mock-up of the Columbus module
0:19:33 > 0:19:35of the European Space Agency,
0:19:35 > 0:19:38which is on the International Space Station.
0:19:39 > 0:19:41And here you see on the outer surface
0:19:41 > 0:19:44the Whipple shield has been implemented everywhere.
0:19:44 > 0:19:46You see here a cutaway part
0:19:46 > 0:19:50and you can see the outer wall, the bumper,
0:19:50 > 0:19:52then you have some stuffing shown here
0:19:52 > 0:19:57and the inner wall, which is finally supposed to stop the particle.
0:20:06 > 0:20:10The layers absorb and dissipate the energy of any strike,
0:20:10 > 0:20:12but the protection is only effective
0:20:12 > 0:20:14for objects up to one centimetre in size.
0:20:22 > 0:20:25Unfortunately, the American Air Force
0:20:25 > 0:20:30only has the technology to track objects bigger than ten centimetres,
0:20:30 > 0:20:32slightly bigger than a cricket ball.
0:20:32 > 0:20:37And that leaves a huge and worrying gap in the space station's defences.
0:20:41 > 0:20:44Objects between one centimetre and ten centimetres, roughly,
0:20:44 > 0:20:48they can neither be avoided nor shielded.
0:20:48 > 0:20:50So there is a dark risk that remains
0:20:50 > 0:20:52even for the International Space Station.
0:21:10 > 0:21:13If the space station was hit by a piece of debris
0:21:13 > 0:21:15of this kind of size...
0:21:17 > 0:21:19..it could be devastating.
0:21:21 > 0:21:24So the space station is a pressurised module.
0:21:24 > 0:21:27That means the pressure inside is greater than the pressure outside.
0:21:27 > 0:21:29It's a vacuum outside the space station.
0:21:29 > 0:21:32And the equivalent down here is a balloon.
0:21:32 > 0:21:34You know, you blow air into a balloon,
0:21:34 > 0:21:37the pressure is greater inside the balloon than outside the balloon.
0:21:37 > 0:21:40And we all know what happens if you stick a pin into a balloon.
0:21:43 > 0:21:46If you look at that balloon bursting in slow motion,
0:21:46 > 0:21:48as the pin goes in, the balloon unzips.
0:21:52 > 0:21:55And that's one of the things that could happen on the station.
0:21:55 > 0:21:59It gets hit by something relatively small, penetrates,
0:21:59 > 0:22:01but because of the pressure inside,
0:22:01 > 0:22:05it just forces the modules just to open up,
0:22:05 > 0:22:07just like a balloon bursting.
0:22:10 > 0:22:12And that happens extremely quickly,
0:22:12 > 0:22:16with no chance that an astronaut in that module could ever get out.
0:22:26 > 0:22:29The space station can manoeuvre out of the way
0:22:29 > 0:22:30of any bigger pieces of junk.
0:22:32 > 0:22:34But as astronaut Sandra Magnus knows,
0:22:34 > 0:22:37it's not like turning the wheel of a car.
0:22:37 > 0:22:39You have to program the kind of burn you want to do.
0:22:39 > 0:22:41You have to program the manoeuvre
0:22:41 > 0:22:43the station needs to get to do the kind of burn you want to do
0:22:43 > 0:22:45based on which jets you're using.
0:22:45 > 0:22:46It takes several days.
0:22:46 > 0:22:48They may have gotten it down faster than that,
0:22:48 > 0:22:51but it's not just, "OK, flip a switch, let's move the station."
0:22:51 > 0:22:52It's not that straightforward.
0:22:54 > 0:22:59In 2014, the station had to move three times
0:22:59 > 0:23:01to avoid large chunks of space debris.
0:23:02 > 0:23:06But as Sandra Magnus discovered in March 2009,
0:23:06 > 0:23:09sometimes there's not enough time to move the station.
0:23:20 > 0:23:23It was mid-morning and I was getting ready to exercise
0:23:23 > 0:23:28and we were just sort of getting into our mid-morning routine, if you will.
0:23:28 > 0:23:30And we got a call that we were having "a red conjunction."
0:23:30 > 0:23:32We were looking around, "What is a red conjunction?"
0:23:32 > 0:23:34Because we hadn't really trained for it.
0:23:38 > 0:23:40A red conjunction is a warning code
0:23:40 > 0:23:43that the space station could be hit by some space junk.
0:23:45 > 0:23:49This warning is only issued when there's no time to move the station.
0:23:51 > 0:23:53It wasn't predicted.
0:23:54 > 0:23:56It was a little bit chaotic
0:23:56 > 0:23:59because this was the first time we had had one of these.
0:23:59 > 0:24:01'Copy, Al. You're on your way.'
0:24:01 > 0:24:04Ground Control were tracking a 13cm chunk
0:24:04 > 0:24:06of a Delta II rocket body,
0:24:06 > 0:24:12about the size of a CD, apparently heading straight for the station.
0:24:12 > 0:24:14And Sandra was sent to the Soyuz capsule,
0:24:14 > 0:24:16the space station's life raft,
0:24:16 > 0:24:19in preparation for a possible evacuation.
0:24:20 > 0:24:25When the Soyuz docks to station, it's put in sort of a sleep mode,
0:24:25 > 0:24:28because you really don't need it while you're on station,
0:24:28 > 0:24:30because it's, you know, your delivery vehicle
0:24:30 > 0:24:32and your go home vehicle.
0:24:32 > 0:24:35But when you're getting ready to evacuate from the station,
0:24:35 > 0:24:37whether it's nominal or a contingency,
0:24:37 > 0:24:38you have to power all that stuff up.
0:24:38 > 0:24:42And there's a certain sequence of things you have to go through to do that.
0:24:50 > 0:24:52But she wasn't panicking.
0:24:52 > 0:24:55It's either going to hit or it's not going to hit.
0:24:55 > 0:24:58And so worrying about it doesn't help you.
0:24:58 > 0:25:01All you have to do is just prepare everything that you need to prepare
0:25:01 > 0:25:05so that, if it hits, then you're in the best possible configuration.
0:25:05 > 0:25:08And if it doesn't hit, well, then, you just go and do it anyway.
0:25:10 > 0:25:12The Soyuz has a small window.
0:25:13 > 0:25:18And as she sat and waited, she couldn't stop herself looking out.
0:25:20 > 0:25:23So I'm looking out the portal thinking, "Oh, maybe I can see it."
0:25:23 > 0:25:26You know, your view is like this, right?
0:25:26 > 0:25:28It's like looking out of a peephole of a door.
0:25:28 > 0:25:30I was laughing to myself, "Go on, there's no way."
0:25:30 > 0:25:34Because if I saw it, it would be really bad, because it'd be right there.
0:25:36 > 0:25:40Fortunately, the junk sailed by and the station was undamaged.
0:25:40 > 0:25:43But the crisis did force the astronauts and Nasa
0:25:43 > 0:25:47to re-evaluate what they would do if it happened again.
0:25:51 > 0:25:52We got through it. It was all good.
0:25:52 > 0:25:55So it wasn't that everybody didn't know what's needed to be done.
0:25:55 > 0:25:57But it's like, what order do you communicate?
0:25:57 > 0:26:01What's the most important thing you communicate? Who communicates what to who?
0:26:01 > 0:26:03So there was a lot of refinement that needed to happen
0:26:03 > 0:26:05and so we instituted that after this.
0:26:11 > 0:26:14'OK, hatch opened and stowed.'
0:26:18 > 0:26:21Since that near miss in 2009,
0:26:21 > 0:26:26the amount of trackable orbital debris has gone up by over 20%
0:26:26 > 0:26:30to 22,000 pieces.
0:26:36 > 0:26:40'Before receiving, gate closed and locked.'
0:26:42 > 0:26:46But scientists calculate that there are hundreds of millions of pieces of debris
0:26:46 > 0:26:48that are too small to track
0:26:48 > 0:26:51hurtling round in the orbits close to Earth.
0:26:51 > 0:26:54'How about just one more check on the reel?'
0:26:54 > 0:26:59Most of them don't present any threat to the space station.
0:26:59 > 0:27:02But they do to the people who live and work up there...
0:27:04 > 0:27:06..the astronauts.
0:27:18 > 0:27:20For emergency doctor Kevin Fong,
0:27:20 > 0:27:24who worked at Nasa in their human spaceflight programme,
0:27:24 > 0:27:28astronauts are at their most vulnerable on the spacewalk.
0:27:33 > 0:27:36'OK, we checked all four systems.'
0:27:38 > 0:27:40'Modulation all four and clean with the go.'
0:27:42 > 0:27:45These guys are out there tumbling around the Earth
0:27:45 > 0:27:47holding onto the space station,
0:27:47 > 0:27:50travelling at 17,500 miles an hour
0:27:50 > 0:27:53250 miles off the ground
0:27:53 > 0:27:55with nothing between them and death
0:27:55 > 0:27:57but this multilayered suit and a visor.
0:27:57 > 0:28:01I mean, that's... that's walking in space.
0:28:01 > 0:28:04'Oh, my goodness, something's fallen out.'
0:28:06 > 0:28:09Throw space junk travelling at similar velocities into the mix
0:28:09 > 0:28:12and the dangers start to get bigger.
0:28:14 > 0:28:16At that speed,
0:28:16 > 0:28:21something as small as a fleck of paint could be life-threatening.
0:28:25 > 0:28:28Just how dangerous has been tested in this special lab
0:28:28 > 0:28:29at the University of Kent.
0:28:37 > 0:28:41This strange-looking assembly of pipes and tubes
0:28:41 > 0:28:45is actually one of the most powerful guns in Britain.
0:28:49 > 0:28:54It can fire objects at roughly ten times the speed of a bullet.
0:28:57 > 0:29:01But today, they're not firing anything as big as a bullet.
0:29:06 > 0:29:11This tiny one-millimetre steel ball is what most space junk looks like.
0:29:12 > 0:29:16In space, small is what's frequent. Large is not very common.
0:29:23 > 0:29:25The ball wrapped in wax
0:29:25 > 0:29:28and similar in size to a tiny piece of debris
0:29:28 > 0:29:31or a fleck of hardened paint is loaded.
0:29:34 > 0:29:39It's the most likely kind of thing to hit an astronaut on a spacewalk.
0:29:42 > 0:29:44'237 in lift.'
0:29:44 > 0:29:47'OK, I am ready to receive it.'
0:29:49 > 0:29:52One of the most vulnerable parts of the spacesuit
0:29:52 > 0:29:55is the astronaut's visor.
0:29:58 > 0:30:01This is a piece of plastic, a polycarbonate,
0:30:01 > 0:30:03which is typically used in space,
0:30:03 > 0:30:06for example as a shield across the visor of the helmet
0:30:06 > 0:30:08an astronaut might wear.
0:30:08 > 0:30:11So he'd be looking out through it, protecting him from the environment.
0:30:11 > 0:30:14What we're going to do with it here is we are going to put it in the gun
0:30:14 > 0:30:18and fire one of our very small particles at 14,000 miles an hour towards it.
0:30:23 > 0:30:26The polycarbonate is the same thickness as the visor.
0:30:37 > 0:30:39So would the visor survive?
0:30:43 > 0:30:47So this is our polycarbonate after the impact experiment.
0:30:47 > 0:30:51So our one-millimetre object travelling at 14,000mph
0:30:51 > 0:30:54has punched straight through the front.
0:30:54 > 0:30:56At the back, there's a slightly larger whole.
0:30:56 > 0:30:59So it's gone through and removed material from the rear surface.
0:30:59 > 0:31:01And that's kept on going and hit what's on the far side,
0:31:01 > 0:31:03potentially an astronaut.
0:31:05 > 0:31:08'OK to go. I have my gate closed and locked.'
0:31:09 > 0:31:13'With that you are go to release the cutters from the internal bearing.'
0:31:14 > 0:31:17The visor's going to be almost non-existent as an obstacle.
0:31:19 > 0:31:21The tiny amount of that energy,
0:31:21 > 0:31:24a fraction of that energy that particle has gets taken up by shattering the visor.
0:31:24 > 0:31:27And in terms of what it would look like to the astronaut,
0:31:27 > 0:31:29well, it's probably going to be the last thing that they see.
0:31:33 > 0:31:36The energy contained within a single fleck of paint
0:31:36 > 0:31:38travelling at these enormous velocities,
0:31:38 > 0:31:41it is much more akin to the energy you see
0:31:41 > 0:31:43contained within a high explosive.
0:31:54 > 0:31:58For astronauts like Jim Reilly, who's walked in space five times,
0:31:58 > 0:32:01the dangers of space junk are part of the job.
0:32:04 > 0:32:07You know, at some point, you get hit by something of any size,
0:32:07 > 0:32:09it's pretty much game over.
0:32:09 > 0:32:12But, you know, we accept those risks even here on Earth.
0:32:12 > 0:32:16You know, you can get hit by a bus and it's just, it's your day, right?
0:32:16 > 0:32:18So you accept that.
0:32:18 > 0:32:20'Good to go to close the thermal hatch.'
0:32:20 > 0:32:22Of course, the astronaut's suit
0:32:22 > 0:32:24presents a much bigger target than the visor.
0:32:24 > 0:32:26But that's more protected.
0:32:26 > 0:32:29'Get all the routing back to the structure itself.
0:32:29 > 0:32:32'Are you good on that?'
0:32:32 > 0:32:35It has a layering system that helps slow down any small objects
0:32:35 > 0:32:37that might pierce the fabric.
0:32:39 > 0:32:41And it also has a built-in safety mechanism.
0:32:43 > 0:32:48The suit can sustain a hole somewhere between an eighth and a quarter of an inch
0:32:48 > 0:32:51and that will still have enough volume within the oxygen tanks
0:32:51 > 0:32:55to give you about 15 minutes to get back into the airlock.
0:32:55 > 0:32:59The problem on the station, though, is that you can be 15 minutes away and further
0:32:59 > 0:33:01when you're doing some of your work.
0:33:04 > 0:33:05'Your left hand is off just now.'
0:33:09 > 0:33:12'OK, captain, complete.'
0:33:14 > 0:33:17ASTRONAUTS TALK INDISTINCTLY
0:33:19 > 0:33:23Spacesuit is kind of a bit of a misnomer.
0:33:23 > 0:33:24It's not a suit.
0:33:24 > 0:33:27It's the world's smallest spacecraft.
0:33:29 > 0:33:32You depend upon it entirely for your life,
0:33:32 > 0:33:35because inside that suit is an atmosphere that you can breathe,
0:33:35 > 0:33:39a warmth enough to keep you alive
0:33:39 > 0:33:43and something that can repel heat when it's out there.
0:33:43 > 0:33:48FEMALE ASTRONAUT SPEAKS INDISTINCTLY
0:33:49 > 0:33:52And it all looks great and it all looks nice and floaty.
0:33:52 > 0:33:54But actually these are some of the most terrifying moments
0:33:54 > 0:33:56in all of human space exploration.
0:33:56 > 0:34:00This is the maximum exposure that an individual can have out there.
0:34:00 > 0:34:03This is where they are stripped of all of the protections
0:34:03 > 0:34:06that have been engineered over years.
0:34:08 > 0:34:11It's hard to think of an environment or a situation
0:34:11 > 0:34:13in which you would be more vulnerable.
0:34:13 > 0:34:18MALE ASTRONAUT SPEAKS INDISTINCTLY
0:34:21 > 0:34:25Up till now, no astronaut has ever come to grief in a spacewalk.
0:34:28 > 0:34:33But for some scientists, the past is no guide to the future.
0:34:33 > 0:34:37When the space age started, Nasa designed the spacesuits
0:34:37 > 0:34:41so that the astronauts could survive impacts of very small dust.
0:34:41 > 0:34:46But as the space age has gone on and bits of paint are flaked away from the outside of spacecraft
0:34:46 > 0:34:51or sometimes a disused satellite explodes and showers space with very fine debris,
0:34:51 > 0:34:55there is more and more debris about the size we've been shooting here today.
0:34:55 > 0:34:57Sooner or later in the next decade or two,
0:34:57 > 0:35:00an astronaut will be struck by something this size.
0:35:07 > 0:35:09But maybe in the future,
0:35:09 > 0:35:12people won't have to risk their lives on the final frontier.
0:35:15 > 0:35:19At the European Space Agency's lab in Holland,
0:35:19 > 0:35:22Dr Andre Schiele is suiting up
0:35:22 > 0:35:24to test the next generation of astronaut.
0:35:31 > 0:35:33He's wearing a high-tech sleeve,
0:35:33 > 0:35:35which is remotely linked to a robot arm.
0:35:37 > 0:35:40Every movement he makes with his hand and arm
0:35:40 > 0:35:42is mimicked by the robot.
0:35:45 > 0:35:49In space, it's a very hostile environment for humans to be
0:35:49 > 0:35:51for several reasons.
0:35:51 > 0:35:53There is debris that can hit astronauts
0:35:53 > 0:35:55when they are doing activities outside.
0:35:55 > 0:35:58If a robotic system is struck by a small part,
0:35:58 > 0:35:59it will probably break,
0:35:59 > 0:36:02but we are not facing life loss.
0:36:02 > 0:36:04So it is much safer to do this
0:36:04 > 0:36:06and we can actually control those robotic systems
0:36:06 > 0:36:10from either inside the safe and shielded environment of the space station
0:36:10 > 0:36:12or even from the ground.
0:36:14 > 0:36:17This cutting-edge technology is still being developed
0:36:17 > 0:36:20and won't come online for a number of years.
0:36:20 > 0:36:22But even when it does,
0:36:22 > 0:36:25Dr Schiele doesn't envisage replacing humans in space.
0:36:28 > 0:36:30We strongly believe at Esa
0:36:30 > 0:36:33that the combination of astronauts and robots
0:36:33 > 0:36:35can be the most powerful one.
0:36:35 > 0:36:38Where not one replaces the other,
0:36:38 > 0:36:41but every system exploits its optimal characteristics.
0:36:43 > 0:36:45So a robot is very good at repeating tasks,
0:36:45 > 0:36:48at doing tasks in very hostile environments.
0:36:48 > 0:36:50And humans are very good at planning tasks,
0:36:50 > 0:36:53at understanding random situations.
0:36:53 > 0:36:57So with the system that we show here, in the telerobotics lab at Esa,
0:36:57 > 0:36:59we are combining the human intelligence
0:36:59 > 0:37:04with the preferences of a robotic manipulator by tele manipulation.
0:37:15 > 0:37:19But orbital debris threatens life on Earth as well as in space.
0:37:22 > 0:37:24And that's because modern life
0:37:24 > 0:37:28is increasingly dependent on satellite technology...
0:37:31 > 0:37:33..from GPS
0:37:33 > 0:37:36to television
0:37:36 > 0:37:38to the weather forecast.
0:37:39 > 0:37:41And in the future,
0:37:41 > 0:37:44we're only going to get more dependent on space technology.
0:37:49 > 0:37:52Our use of space is going to grow.
0:37:52 > 0:37:55We're already relying on many services
0:37:55 > 0:37:58that are provided by satellites already.
0:37:58 > 0:38:00That situation is unlikely to change.
0:38:00 > 0:38:03You know, we're only going to place more demands
0:38:03 > 0:38:06on satellites into the future.
0:38:06 > 0:38:11And, you know, if that happens in combination with a growing debris problem,
0:38:11 > 0:38:14then there're going to be issues arising.
0:38:18 > 0:38:21And that debris problem could be about to get worse.
0:38:22 > 0:38:26Scientists have only recently begun to understand the risks
0:38:26 > 0:38:30of 17 old Russian SL-16 rocket bodies
0:38:30 > 0:38:32orbiting within 50km of each other.
0:38:38 > 0:38:41They're big. About the size of a railway carriage.
0:38:43 > 0:38:47We showed that there is a one in 400 chance over the next ten years
0:38:47 > 0:38:52of two of those SL-16 rocket bodies colliding.
0:38:55 > 0:38:58So you may ask, that doesn't sound like that's too bad.
0:38:58 > 0:39:02I'm not sure how many of you would go and take the subway tomorrow into work
0:39:02 > 0:39:06if there is a one in 400 chance that that subway wasn't going to make it into work.
0:39:11 > 0:39:16So far, those old rocket bodies haven't come close to each other.
0:39:19 > 0:39:22But could there be an even greater danger
0:39:22 > 0:39:26threatening our dependence on space?
0:39:26 > 0:39:29What I'm really more concerned about is kind of like the canary in the mine.
0:39:29 > 0:39:32I don't care about the big breakups.
0:39:32 > 0:39:35I care about the satellites that are failing for unknown reasons
0:39:35 > 0:39:39because, statistically, you know you have many more
0:39:39 > 0:39:41of the lethal, non-trackable objects
0:39:41 > 0:39:44than you do of the trackable fragments
0:39:44 > 0:39:46that are going to break things up.
0:39:46 > 0:39:48So what a precursor should be,
0:39:48 > 0:39:51an indicator that we're getting close to the Kessler Syndrome
0:39:51 > 0:39:55is that we have many more satellites that have anomalies for unknown reasons.
0:39:55 > 0:39:58'It's coming off. Go for deploy.'
0:40:01 > 0:40:04'Oh, roger. Liftoff and the clock is started.'
0:40:13 > 0:40:17This huge satellite was built in Britain in 2002...
0:40:19 > 0:40:21..for the European Space Agency.
0:40:24 > 0:40:28LAUNCH COUNTDOWN IN FRENCH
0:40:32 > 0:40:35It was the largest civilian Earth observation satellite
0:40:35 > 0:40:37ever fired into space.
0:40:38 > 0:40:41And it was very successful.
0:40:43 > 0:40:45But in April 2012...
0:40:47 > 0:40:50..it suddenly stopped working.
0:40:55 > 0:41:00So all of a sudden it went from generating huge amounts of data for scientists down on the ground
0:41:00 > 0:41:03to basically one of the biggest pieces of junk that we see on orbit.
0:41:04 > 0:41:07Some scientists suspect Envisat
0:41:07 > 0:41:10might have been disabled by space junk.
0:41:12 > 0:41:16Sometimes there is no clear indication and it's just a suspicion
0:41:16 > 0:41:20that smaller particles have impacted the satellite and done some damage.
0:41:20 > 0:41:25You can cut a cable easily or you can damage some structural parts.
0:41:25 > 0:41:28So it certainly will happen. And it has happened in space.
0:41:32 > 0:41:38Envisat is now hurtling around the world at over 7km per second,
0:41:38 > 0:41:43in the same orbit as all of the other Earth observational satellites.
0:41:46 > 0:41:50But the much greater threat of a collision with some junk
0:41:50 > 0:41:53was highlighted when scientists built a computer model of its path
0:41:53 > 0:41:55through the largest debris field.
0:41:57 > 0:41:58So what we're seeing here,
0:41:58 > 0:42:02this is the view from Envisat as it's travelling around the Earth.
0:42:02 > 0:42:06These are all the other debris objects that we can currently track from the ground.
0:42:06 > 0:42:09As we're moving along the orbit here,
0:42:09 > 0:42:15what you see is there are plenty of objects that are passing in front of Envisat.
0:42:15 > 0:42:17In some cases, passing right next to Envisat.
0:42:18 > 0:42:21Now, when we get to the poles like this,
0:42:21 > 0:42:25you can see just how crowded the environment actually is.
0:42:25 > 0:42:28And Envisat is just going through that now without any kind of control.
0:42:28 > 0:42:32So there's no way it can manoeuvre to avoid any collision.
0:42:32 > 0:42:36You know, some of these things passing at 14km per second.
0:42:36 > 0:42:38Huge amounts of energy's involved.
0:42:49 > 0:42:52Removing Envisat from its dangerous orbit
0:42:52 > 0:42:54is obviously a pressing problem.
0:42:56 > 0:42:58The satellite company Airbus
0:42:58 > 0:43:01is at the forefront of the race against time
0:43:01 > 0:43:04to bring Envisat back to Earth.
0:43:08 > 0:43:13They build some of the world's most sophisticated and complex satellites
0:43:13 > 0:43:16in their high-tech clean rooms.
0:43:16 > 0:43:20But they're figuring out how to solve the Envisat problem
0:43:20 > 0:43:22in much more humble surroundings...
0:43:24 > 0:43:26..the company's converted bike shed.
0:43:28 > 0:43:33And what they've come up with is deceptively simple.
0:43:40 > 0:43:42They plan to harpoon it.
0:43:43 > 0:43:47This demonstration allows us to prove that we can target a small object,
0:43:47 > 0:43:51a very lightweight object very accurately.
0:43:51 > 0:43:57If we can do that, then we can certainly go and capture very big objects and very heavy objects,
0:43:57 > 0:44:01which is essentially the main targets that we want to capture.
0:44:10 > 0:44:13They hope to launch a chaser satellite,
0:44:13 > 0:44:16which would carefully approach Envisat
0:44:16 > 0:44:18or any other defunct satellite
0:44:18 > 0:44:20and then fire the harpoon.
0:44:24 > 0:44:29So this system will capture those items of debris,
0:44:29 > 0:44:35tow them out of the orbits where they might collide with active satellites
0:44:35 > 0:44:39and allow them to burn up safely in the atmosphere.
0:44:40 > 0:44:45So the idea is to have a system which takes them away from where they cause a problem
0:44:45 > 0:44:48and basically destroy them safely.
0:44:54 > 0:44:56It sounds great in theory,
0:44:56 > 0:44:58but it may not be easy in practice.
0:45:01 > 0:45:04You're firing something, it's going to be travelling pretty quickly.
0:45:04 > 0:45:07It's going to hit the other spacecraft.
0:45:07 > 0:45:10OK? And that's kind of the situation that we're trying to avoid in the first place.
0:45:10 > 0:45:13We're artificially generating a collision here.
0:45:13 > 0:45:16The whole point of this spacecraft,
0:45:16 > 0:45:19of, you know, removing that big junk
0:45:19 > 0:45:22is that we reduce the number of objects that we have on orbit.
0:45:22 > 0:45:25So we don't want to be generating any new debris.
0:45:32 > 0:45:35The harpoon strike could have a much bigger unintended impact.
0:45:39 > 0:45:42Where on that spacecraft are you going to fire your harpoon?
0:45:42 > 0:45:44There are all sorts of things inside there that,
0:45:44 > 0:45:47you know, potentially you can have problems with.
0:45:48 > 0:45:52On the inside of the satellite, we have things like propulsion lines,
0:45:52 > 0:45:56which you can see here, which carry the propellant for the thrusters.
0:45:56 > 0:46:00And electronics boxes and various other bits of equipment.
0:46:00 > 0:46:02So when we punch through this panel,
0:46:02 > 0:46:08we need to take into account that there might be this sort of equipment on the other side.
0:46:10 > 0:46:13Hitting the extremely volatile propellant with a harpoon
0:46:13 > 0:46:16would almost certainly cause an explosion.
0:46:18 > 0:46:20So Dr Jamie Reid and his colleagues
0:46:20 > 0:46:23have been poring over the blueprints of Envisat
0:46:23 > 0:46:25to make sure they can target
0:46:25 > 0:46:28precisely where they want the harpoon to land.
0:46:35 > 0:46:40But there's a final obstacle that might prove insurmountable.
0:46:40 > 0:46:43This is a pretty big spacecraft.
0:46:43 > 0:46:46It needs to be big because we're kind of manhandling this one.
0:46:46 > 0:46:49You know, you're not going to send a mouse to grab an elephant.
0:46:49 > 0:46:50So this spacecraft is big.
0:46:50 > 0:46:53That means it's going to go onto a big rocket.
0:46:53 > 0:46:56And that rocket is going to cost a lot of money.
0:46:56 > 0:46:58So we've invested huge amounts of money into this.
0:46:58 > 0:47:03And its job, essentially, is to grab a bit of junk and then burn it up.
0:47:03 > 0:47:06You know, so it's not really performing any science, anything else.
0:47:06 > 0:47:10That's what its job is for and we're spending huge amounts of money to do that.
0:47:11 > 0:47:14It's certainly true that if you had one satellite
0:47:14 > 0:47:18to go and catch one piece of debris, it would be very inefficient.
0:47:18 > 0:47:20So the advantage of the harpoon design
0:47:20 > 0:47:22is we can have one chaser satellite
0:47:22 > 0:47:24that has lots of different harpoons on it
0:47:24 > 0:47:27and it can go and capture multiple pieces of debris.
0:47:41 > 0:47:44There are other plans to remove defunct satellites,
0:47:44 > 0:47:47including capturing them in a net...
0:47:49 > 0:47:51..sticking a magnetic thruster onto the body...
0:47:53 > 0:47:56..physically grabbing drifting spacecraft...
0:47:57 > 0:48:00..firing a laser beam to change their orbit...
0:48:01 > 0:48:05..and even using solar radiation to sail them off to safety.
0:48:09 > 0:48:12But the debris problem is so huge
0:48:12 > 0:48:15that it might be beyond all of these solutions.
0:48:16 > 0:48:19If I take off a certain number of objects over a certain period of time,
0:48:19 > 0:48:22I'm going to reduce the probability of collision.
0:48:22 > 0:48:25Unfortunately, from the analysis that's been done,
0:48:25 > 0:48:29it's about 35 to 50 removals to prevent one collision.
0:48:31 > 0:48:32That's not great, right?
0:48:32 > 0:48:36A lot of people think, "I remove one object, I've stopped one breakup."
0:48:36 > 0:48:38That is not the way it's going to work.
0:48:38 > 0:48:41It's statistical in nature, it's being very proactive.
0:48:41 > 0:48:44It doesn't mean we shouldn't do it. But it's not one for one.
0:48:46 > 0:48:48It's going to be a huge, huge cost.
0:48:48 > 0:48:52Do we spend the money on removing all these objects?
0:48:52 > 0:48:54Or let's not spend the money.
0:48:54 > 0:48:56Let's leave all the objects in orbit
0:48:56 > 0:48:59and then we take the risk that some of those are going to be hit,
0:48:59 > 0:49:01they're going to generate more fragments
0:49:01 > 0:49:04and we end up in the situation where, you know,
0:49:04 > 0:49:06Earth orbit is completely congested,
0:49:06 > 0:49:09full of fragments and we can't launch new space missions.
0:49:17 > 0:49:21Of course, satellites continue to be launched at about 120 a year.
0:49:25 > 0:49:28But that's not what has scientists most concerned.
0:49:32 > 0:49:35They're worried about these things.
0:49:35 > 0:49:37CubeSats.
0:49:39 > 0:49:43They're far cheaper than your conventional large spacecraft.
0:49:43 > 0:49:46And what that means is we can put up more of these
0:49:46 > 0:49:48and they can perform the kind of space missions
0:49:48 > 0:49:51that we wouldn't be able to contemplate with a larger spacecraft.
0:49:54 > 0:49:57What helps keep the cost down is that they're so small
0:49:57 > 0:50:00they can be launched as part of the payload of a bigger satellite
0:50:00 > 0:50:03or even from the space station.
0:50:03 > 0:50:06They're quite simply thrown into orbit.
0:50:07 > 0:50:10The disadvantage is that they're not manoeuvrable.
0:50:13 > 0:50:17In the end, the problem is similar to a collision, if you like.
0:50:17 > 0:50:19The release event of these objects
0:50:19 > 0:50:22is more or less identical
0:50:22 > 0:50:25to the large release of a cloud of fragments,
0:50:25 > 0:50:28because these CubeSats are not manoeuvrable.
0:50:28 > 0:50:30They cannot avoid collisions.
0:50:32 > 0:50:35Even though the CubeSat is small,
0:50:35 > 0:50:37there's is probably sufficient mass in here
0:50:37 > 0:50:40that if it was to hit a larger spacecraft,
0:50:40 > 0:50:43you know, at 10km per second,
0:50:43 > 0:50:46it would cause a catastrophic breakup of that spacecraft.
0:50:46 > 0:50:48You know, the mass of these could be
0:50:48 > 0:50:51anywhere between 3kg all the way up to 20kg
0:50:51 > 0:50:53and that's enough mass
0:50:53 > 0:50:57to completely destroy a satellite like Envisat.
0:51:06 > 0:51:10Around 100 of these mini satellites were launched in 2014.
0:51:10 > 0:51:14And that number is only set to increase.
0:51:20 > 0:51:22There is no law governing space operations
0:51:22 > 0:51:27and that's primarily because space isn't divided up by national boundaries.
0:51:29 > 0:51:33Space, in the end, is a resource. It needs to be shared globally.
0:51:33 > 0:51:36There is no space above your country that you can reserve.
0:51:36 > 0:51:39Spaceflight happens by orbiting around the full Earth.
0:51:41 > 0:51:44So you have to share the whole space.
0:51:44 > 0:51:47You need to have consensus globally
0:51:47 > 0:51:51on what we do with this precious space.
0:52:02 > 0:52:07Consensus isn't always possible to achieve.
0:52:08 > 0:52:13So the United States, the most powerful spacefaring nation,
0:52:13 > 0:52:16is taking matters into its own hands.
0:52:26 > 0:52:30It's not going to break the bank by investing in unproven technology
0:52:30 > 0:52:32to clean up the debris problem.
0:52:33 > 0:52:36But the Federal Government is spending a billion dollars
0:52:36 > 0:52:40on a new tracking system called Space Fence.
0:52:46 > 0:52:49Space Fence will provide the capability
0:52:49 > 0:52:52to detect, track and catalogue objects
0:52:52 > 0:52:55all the way from the baseball size
0:52:55 > 0:52:57down to sort of marble size,
0:52:57 > 0:52:59depending on the altitude.
0:53:02 > 0:53:06So instead of just tracking 22,000 large objects,
0:53:06 > 0:53:09Space Fence will now allow the Space Surveillance Network
0:53:09 > 0:53:14to track up to 200,000 much smaller objects.
0:53:20 > 0:53:23To be honest, a lot of people would say,
0:53:23 > 0:53:26"Well, let's just put our head in the sand and ignore the problem."
0:53:26 > 0:53:30Well, that's just an irresponsible way to look at the problem.
0:53:30 > 0:53:32If you can see that debris and if you can avoid that debris,
0:53:32 > 0:53:34you need to do everything you can to do that.
0:53:34 > 0:53:38Because every one of those events that is a collision
0:53:38 > 0:53:41creates thousands of other pieces of debris now that you have to track.
0:53:43 > 0:53:45This new system is called Space Fence
0:53:45 > 0:53:48because it produces a fence-like radar beam.
0:53:49 > 0:53:53It's the size of the radar and the huge increase in its frequency
0:53:53 > 0:53:57that allows it to track much smaller objects.
0:53:57 > 0:54:01When an object crosses that fence, we detect it.
0:54:01 > 0:54:05And then we can electronically steer this energy
0:54:05 > 0:54:09so that we can track it very precisely.
0:54:09 > 0:54:13And then once you develop a track on it,
0:54:13 > 0:54:16at that point I can then use physics
0:54:16 > 0:54:18to predict where it's going to be in the future.
0:54:18 > 0:54:22So every time the object goes over the site,
0:54:22 > 0:54:25we would then collect more information on it, more data,
0:54:25 > 0:54:29which allows us to refine the estimate of where it is at,
0:54:29 > 0:54:31again, so that we can predict where it's going to be in the future.
0:54:44 > 0:54:46But there are limitations to this system.
0:54:48 > 0:54:52There are millions of objects of varying sizes orbiting Earth,
0:54:52 > 0:54:55but it's only the thousand or so operational satellites
0:54:55 > 0:54:58that can be moved to avoid a collision.
0:55:06 > 0:55:10So even with the latest technology,
0:55:10 > 0:55:12can science make any worthwhile predictions
0:55:12 > 0:55:15about what might happen in the future?
0:55:15 > 0:55:18What I expect is going to happen is not going to be at all
0:55:18 > 0:55:21what anybody else that you're going to film is going to say.
0:55:21 > 0:55:23Because I don't know what the answer is.
0:55:23 > 0:55:26So I'm just going to tell you you have to live with ambiguity
0:55:26 > 0:55:30and I believe that it will not unfold
0:55:30 > 0:55:36in a predictable, linear, consistent way from anyway that we believe.
0:55:36 > 0:55:40It's going to be sporadic and it's going to be unpredictable
0:55:40 > 0:55:43and we're all going to act surprised
0:55:43 > 0:55:46and myself and Don Kessler and Hugh Lewis are going to go back and go,
0:55:46 > 0:55:49"The variance is large. We told you."
0:55:53 > 0:55:56MALE ASTRONAUT TALKS INDISTINCTLY
0:55:57 > 0:56:00'Right, that looks like it's in there.'
0:56:05 > 0:56:10If Kessler's calculations about the increase in the debris problem are right,
0:56:10 > 0:56:12and so far they have been,
0:56:12 > 0:56:15then scientists forecast that this is what the orbits around Earth
0:56:15 > 0:56:18will look like in the next few centuries.
0:56:25 > 0:56:27'OK, I am ready to receive it.'
0:56:32 > 0:56:35We're using space all the time.
0:56:35 > 0:56:39You know, when we look into the future, that's only going to continue
0:56:39 > 0:56:41and we're going to make more use of space.
0:56:41 > 0:56:43'It did wiggle.
0:56:43 > 0:56:47'To set that to be effective,
0:56:47 > 0:56:50'it needs to be pointed forward.'
0:56:51 > 0:56:54You know, if we are connected via space all the time,
0:56:54 > 0:56:57then space becomes our single point of failure.
0:56:57 > 0:56:59And we've got to tackle that problem.
0:57:08 > 0:57:11But there are also idealistic
0:57:11 > 0:57:13as well as practical reasons
0:57:13 > 0:57:15for wanting to preserve our access
0:57:15 > 0:57:20to what's now one of our most precious resources.
0:57:25 > 0:57:30I want my kids and my kids' kids to be able to explore space.
0:57:30 > 0:57:34And if we ruin the environment, we can't do that.
0:57:34 > 0:57:38And that would be tragic, because my passion for space
0:57:38 > 0:57:42came when I was ten years old and I watched Apollo 11
0:57:42 > 0:57:44and I watched Neil Armstrong walk on the moon
0:57:44 > 0:57:48and that magic that created that feeling in me that said,
0:57:48 > 0:57:50"I want to do space,"
0:57:50 > 0:57:53I want my kids and my kids' kids to have that opportunity.
0:57:53 > 0:57:56And if the space environment is ruined, that will never happen.