0:00:03 > 0:00:05It must be right first time.
0:00:05 > 0:00:07You can't service it or bring it back
0:00:07 > 0:00:09or complain to the manufacturer that it doesn't work.
0:00:13 > 0:00:17Failure in space is not an option. If something goes wrong,
0:00:17 > 0:00:21customers are not happy and they don't come back to you again.
0:00:25 > 0:00:27So what we've got here
0:00:27 > 0:00:30is the startings of a telecommunications satellite.
0:00:30 > 0:00:34We've got seven smaller thrusters and we have a main engine,
0:00:34 > 0:00:36which is fitted inside the cone.
0:00:44 > 0:00:47If we sent a spacecraft up into space with no insulation,
0:00:47 > 0:00:51the distortions caused by the very temperature differences
0:00:51 > 0:00:53would buckle the structure and destroy it.
0:01:03 > 0:01:07If the heart stops, the patient dies.
0:01:07 > 0:01:10If the quartz crystal stops oscillating, the satellite will die.
0:01:14 > 0:01:16If I say I work on satellites...
0:01:16 > 0:01:18"What, you put the dishes on the walls, do you?"
0:01:18 > 0:01:22They just don't... They don't understand
0:01:22 > 0:01:24that there's something up there as well, in space.
0:01:24 > 0:01:30The moments leading up to the firing of that main engine is very tense.
0:01:37 > 0:01:39It's the nearest we get to science fiction.
0:01:39 > 0:01:43It's just something people dream of. We sort of live a little bit of that dream.
0:01:50 > 0:01:55Space is incredibly special. What we do is quite exceptional here.
0:02:21 > 0:02:24After almost two years of precision engineering
0:02:24 > 0:02:27and costing over £100 million,
0:02:27 > 0:02:30a six-tonne telecommunications satellite
0:02:30 > 0:02:33is sitting on top of this rocket.
0:02:33 > 0:02:34In terms of the satellite,
0:02:34 > 0:02:39the risk here of course is that it's now about to be shaken
0:02:39 > 0:02:40from the rocket motors.
0:02:43 > 0:02:46It's also going to get a fantastic thrust load on it.
0:02:49 > 0:02:53And now it's just one day away from being fired into orbit.
0:02:58 > 0:03:01The amount of testing that we do to verify it effectively
0:03:01 > 0:03:06never guarantees you 100% but it guarantees you that you've got
0:03:06 > 0:03:10a very, very high probability of success and that's what we go for.
0:03:12 > 0:03:15The violence of the launch is the most dangerous moment
0:03:15 > 0:03:16of a satellite's life.
0:03:16 > 0:03:19We have to make sure it survives this phase
0:03:19 > 0:03:21and then it can go into operation.
0:03:21 > 0:03:24This is the bit where we all get that, er...
0:03:24 > 0:03:28A little bit of butterflies in the stomach.
0:03:28 > 0:03:31And although it's being launched in faraway French Guiana,
0:03:31 > 0:03:34most of it was designed and built in Britain.
0:03:50 > 0:03:53We're on the A1 heading south at the moment.
0:03:53 > 0:03:56It's about quarter to eight in the morning.
0:03:56 > 0:04:00I've done this trip for the last 30 years.
0:04:01 > 0:04:04Bob Graham is a site director at Astrium,
0:04:04 > 0:04:08one of the biggest spacecraft manufacturers in the world.
0:04:10 > 0:04:11If people say, "Who do you work for?"
0:04:11 > 0:04:14and I mention the name of the company
0:04:14 > 0:04:17there's often a slightly quizzical look on their face.
0:04:17 > 0:04:19Then it becomes quite a surprise when you say,
0:04:19 > 0:04:22"Well, I work in the space industry."
0:04:23 > 0:04:26When the Space Race was at its height in the 1960s,
0:04:26 > 0:04:29the United Kingdom had virtually no space industry.
0:04:33 > 0:04:36Today, British engineers lead the world in satellite design
0:04:36 > 0:04:38and manufacture.
0:04:38 > 0:04:40Working in space is always something different
0:04:40 > 0:04:44and there's not many people in the industry.
0:04:44 > 0:04:47So in the pub when someone says, "What do you do for a living?"
0:04:47 > 0:04:49You say, "I work in the space industry,"
0:04:49 > 0:04:51they do give you a funny look.
0:04:56 > 0:04:58We watched the moon landings
0:04:58 > 0:05:00and everything that NASA did was quite incredible.
0:05:00 > 0:05:04For me, I can't quite believe I'm being able to do this.
0:05:18 > 0:05:22Yeah, we've known each other a long time.
0:05:22 > 0:05:2426 years? Haven't we?
0:05:24 > 0:05:25Is it that long?
0:05:25 > 0:05:27- I think so.- God.- Yeah.- Oh, dear.
0:05:29 > 0:05:32We don't look that old either, do we?
0:05:35 > 0:05:38What's Mr Cross up to? You visitors are all the same!
0:05:40 > 0:05:42Astrium have factories all across Europe
0:05:42 > 0:05:46but employ around 3,500 people in the UK.
0:05:47 > 0:05:51Every satellite the company builds starts life here
0:05:51 > 0:05:54just outside London on their site in Stevenage.
0:05:55 > 0:05:57I've worked here for nearly 30 years.
0:05:57 > 0:06:01I came to Stevenage in 1982 for what was sold to me
0:06:01 > 0:06:05as a 12-18 month position and I've been here ever since.
0:06:05 > 0:06:07It gets into your blood.
0:06:08 > 0:06:11It's a really, really good job to have.
0:06:11 > 0:06:14There's not many areas within in the country
0:06:14 > 0:06:17where you can actually work on spacecraft.
0:06:17 > 0:06:22Telecommunication satellites are an integral part of the modern world.
0:06:27 > 0:06:30They allow us to send television pictures and communicate
0:06:30 > 0:06:34over vast distances using all of today's modern technology.
0:06:36 > 0:06:38But because they operate in deep space,
0:06:38 > 0:06:42they have to incorporate some extremely complex engineering.
0:06:43 > 0:06:47A modern communications satellite needs to be capable of surviving
0:06:47 > 0:06:49the possible impact of debris
0:06:49 > 0:06:52travelling at thousands of metres per second.
0:06:52 > 0:06:55And they need to be able to operate in temperatures that fluctuate
0:06:55 > 0:06:58between minus 200 degrees Centigrade
0:06:58 > 0:07:01to a blistering 150 degrees Centigrade.
0:07:03 > 0:07:06And yet, the satellite has to continuously operate
0:07:06 > 0:07:11for a guaranteed 15 years, because out in space,
0:07:11 > 0:07:14there's absolutely no prospect of repair.
0:07:18 > 0:07:20I think people do take it for granted.
0:07:20 > 0:07:23So if you pick up your mobile phone to make a phone call
0:07:23 > 0:07:26you don't realise it's bouncing off a satellite. Or you turn on your TV.
0:07:26 > 0:07:29It's just stuff you do everyday without thinking about it.
0:07:29 > 0:07:35- The upper quadrant, section five...- Yeah?- ..looked fine.
0:07:41 > 0:07:43A modern telecommunications satellite
0:07:43 > 0:07:47can be over five metres high and three metres wide.
0:07:49 > 0:07:51Although astonishingly complicated,
0:07:51 > 0:07:56there are basically two distinct parts forming its main body.
0:07:57 > 0:07:59The mechanics...
0:08:00 > 0:08:02and the electronics.
0:08:05 > 0:08:08The mechanics make up what's called the service module.
0:08:09 > 0:08:12And the electronics make up the communications module.
0:08:19 > 0:08:23The satellite's central skeleton is built around a carbon fibre cylinder
0:08:23 > 0:08:28connected to aluminium panels which hold four fuel tanks,
0:08:28 > 0:08:32a main engine, thrusters and batteries.
0:08:33 > 0:08:36This is the service module.
0:08:36 > 0:08:39On top of it sits the communications module
0:08:39 > 0:08:43which carries the satellite's complex electronic payload.
0:08:43 > 0:08:45Also added are solar arrays.
0:08:45 > 0:08:48Attached to the main body, they capture sunlight
0:08:48 > 0:08:52which is converted into electric power, and antenna dishes
0:08:52 > 0:08:54that will transmit and receive signals from Earth.
0:08:57 > 0:09:00And by looking at different stages of the build
0:09:00 > 0:09:03it's possible to understand how they're put together.
0:09:03 > 0:09:05From the manufacturing viewpoint
0:09:05 > 0:09:07this is the beginning of the process.
0:09:07 > 0:09:11The build begins with a central core, the skeleton of the satellite.
0:09:11 > 0:09:15Strands of carbon fibre coated with resin
0:09:15 > 0:09:18are wound into a complex pattern to make the cylinder
0:09:18 > 0:09:20as strong and light as possible.
0:09:24 > 0:09:28When it's finished and vertical it weighs just 20kg
0:09:28 > 0:09:30and is ready for the next stage of construction.
0:09:32 > 0:09:36In here is where we produce our panels, our honeycomb panels.
0:09:36 > 0:09:40Aluminium skins. Very, very thin skins, very lightweight.
0:09:40 > 0:09:42Low mass is key in terms of space
0:09:42 > 0:09:45and we use aluminium because it's good structurally.
0:09:47 > 0:09:50The aluminium panels are attached to the central cylinder
0:09:50 > 0:09:52forming more of the basic structure.
0:09:56 > 0:09:59John Richards has been building these
0:09:59 > 0:10:02for almost his whole working life.
0:10:02 > 0:10:06We're just putting the flight bolts into the SM floor
0:10:06 > 0:10:12and that attaches the floors to the central structure.
0:10:12 > 0:10:16I'm not sure how many bolts, probably about 20 in each quadrant.
0:10:18 > 0:10:22I don't suppose, really, people just think of satellites
0:10:22 > 0:10:25as something that's up in space orbiting round.
0:10:25 > 0:10:29I don't suppose they think of actually what goes into building them.
0:10:29 > 0:10:32You take your time, because as you're probably aware
0:10:32 > 0:10:34that these things are worth a lot of money.
0:10:34 > 0:10:37And it only takes us to make one slight mistake
0:10:37 > 0:10:39and it could end up costing millions of pounds.
0:10:39 > 0:10:43Best thing about working here is the people like John and people that have been here years,
0:10:43 > 0:10:47always willing to pass on experience and to help you out.
0:10:47 > 0:10:51After the basic structure is finished
0:10:51 > 0:10:54the rest of the systems can be added.
0:10:54 > 0:10:58Once I've gone through my final testing we have a big clean down,
0:10:58 > 0:11:01make sure it's particle free, ready to be accepted
0:11:01 > 0:11:06into Mick's area and I'll give him a shout and usually that's it.
0:11:06 > 0:11:11I mean it's very casual, it's just, "When you going to be ready?"
0:11:11 > 0:11:14"Tomorrow", whatever, and just hand it over to him.
0:11:14 > 0:11:19Satellites have to be built in extremely clean environments
0:11:19 > 0:11:23because any dirt inside the moving parts can have devastating effects
0:11:23 > 0:11:26once they're in space.
0:11:26 > 0:11:30In fact there are special areas of the factory that actually have fewer
0:11:30 > 0:11:34dust particles than you'd find in a typical hospital operating theatre.
0:11:34 > 0:11:39And in here, engineer Graham Viney and team leader Mick Atkinson
0:11:39 > 0:11:43have the tricky task of managing the assembly and integration
0:11:43 > 0:11:47of the fuel tanks, the pipe work and the engines of the service module.
0:11:47 > 0:11:51We do get problems now and again because when it's designed,
0:11:51 > 0:11:54it's all done on a model and then when it comes down to us
0:11:54 > 0:11:59it is quite a bit different in the real life, putting it together.
0:12:01 > 0:12:05There's certain things that we know we can't do in the design
0:12:05 > 0:12:09because it just won't be able to be done on the shop floor.
0:12:09 > 0:12:13So what we've got here is the overall service module
0:12:13 > 0:12:17or the startings of the service module of the telecommunications satellite.
0:12:17 > 0:12:23What you can see are two tanks of an eventual four tank propellant system.
0:12:23 > 0:12:28On the outside, in several locations, we've got seven smaller thrusters
0:12:28 > 0:12:30and we have a main engine, a liquid apogee engine,
0:12:30 > 0:12:32which is fitted inside the cone.
0:12:35 > 0:12:38The service module carries four fuel tanks,
0:12:38 > 0:12:40all placed around the central core.
0:12:40 > 0:12:44Each fuel tank can withstand an internal pressure equal
0:12:44 > 0:12:47to being over 200 metres underwater.
0:12:50 > 0:12:52The fuel is used for the satellite's engines.
0:12:54 > 0:12:59The main engine fires the satellite out into orbit after it's launched
0:12:59 > 0:13:02and then, for the rest of its lifespan, the other seven pairs
0:13:02 > 0:13:07of smaller thrusters will keep the satellite in its orbit.
0:13:07 > 0:13:10The fuel for all of these engines is delivered
0:13:10 > 0:13:13by one of the most explosive mixtures known to man -
0:13:13 > 0:13:20Nitrogen Tetroxide and Monomethyl Hydrozene, or NTO and MMH.
0:13:20 > 0:13:24As you can guess from the names, these aren't particularly
0:13:24 > 0:13:28pleasant liquids, so extremely toxic and extremely hazardous.
0:13:28 > 0:13:33If you take in any of the NTO or the MMH,
0:13:33 > 0:13:38basically you will suffer from burns, internal burning
0:13:38 > 0:13:42and then eventually it leads to death. They are lethal.
0:13:43 > 0:13:47The reason for choosing these dangerous fuels is simple -
0:13:47 > 0:13:49their explosive quality.
0:13:49 > 0:13:52The more explosive the mixture, the bigger the thrust,
0:13:52 > 0:13:54and the less fuel you need.
0:13:54 > 0:14:00But at three tonnes, this volatile mixture is still half the satellite's launch weight.
0:14:00 > 0:14:03And with such an explosive power, the tanks need to be tested to destruction
0:14:03 > 0:14:07to ensure they'll survive the trip into space.
0:14:09 > 0:14:12Part of the testing of the propellant tanks
0:14:12 > 0:14:15is to take it to an actual burst pressure.
0:14:15 > 0:14:19We don't test it with gas, we tend to test it with water.
0:14:19 > 0:14:24We increase the pressure and we get up towards 49 bar
0:14:24 > 0:14:26and the tank will split.
0:14:47 > 0:14:49Although the tanks won't be filled with fuel
0:14:49 > 0:14:54until just before the launch, it's still delicate work fitting them.
0:14:56 > 0:14:59We're just about to install the third propellant tank
0:14:59 > 0:15:01into the structure.
0:15:01 > 0:15:04Two are already installed, this is the third one.
0:15:08 > 0:15:11It is quite tricky, yeah. And it's worth a lot of money,
0:15:11 > 0:15:16of course, as well. About the price of a good house, actually, yeah.
0:15:18 > 0:15:21The propellant tanks are built from titanium
0:15:21 > 0:15:25because the metal doesn't react with the fuel in any way.
0:15:28 > 0:15:31And they are machined to be wafer thin.
0:15:35 > 0:15:38'We've got to be so careful that no damage occurs
0:15:38 > 0:15:43'during this process, so it's quite delicate.
0:15:45 > 0:15:48'It never goes wrong. It can't. It can't go wrong.'
0:15:48 > 0:15:49LAUGHS
0:15:53 > 0:15:57'Yeah, it's quite a big operation in the tasks that we perform'
0:15:57 > 0:16:00so it's good to get it out of the way.
0:16:00 > 0:16:02We've got it off to a T now.
0:16:02 > 0:16:06Hopefully, tomorrow we'll be putting the other tank in.
0:16:09 > 0:16:12It's the end of a successful day, and so, with the tanks fitted,
0:16:12 > 0:16:17the next stage of the build will be adding the engines.
0:16:29 > 0:16:31So when I tell people I work in the space industry,
0:16:31 > 0:16:36it either sparks conversation and genuine interest
0:16:36 > 0:16:38or is a complete conversation killer.
0:16:39 > 0:16:44The concept of satellites came from Arthur C Clarke back in 1945.
0:16:44 > 0:16:49He thought, "How can we transmit data from one side of the Earth
0:16:49 > 0:16:50"to the other side of the Earth?"
0:16:50 > 0:16:53These things will make possible a world in which
0:16:53 > 0:16:57we can be in instant contact with each other, wherever we may be.
0:17:00 > 0:17:05'Men will no longer commute, they will communicate.'
0:17:12 > 0:17:16With the launch of Telstar in 1962, transmitting sound and vision
0:17:16 > 0:17:20across continents and oceans became a reality.
0:17:20 > 0:17:24'We have acquired the Telstar, Captain Booth puts his thumb up.
0:17:24 > 0:17:27'And there is the picture direct from Telstar.
0:17:27 > 0:17:29'This is the sort of image
0:17:29 > 0:17:33'and the sort of sound on which, in fact, the future
0:17:33 > 0:17:36'of inter-continental telecommunications
0:17:36 > 0:17:39'via space vehicles is built.'
0:17:41 > 0:17:44If you threw something at the horizon
0:17:44 > 0:17:47it would just fall and drop.
0:17:47 > 0:17:51If you threw it hard enough, you could probably throw it
0:17:51 > 0:17:55past the horizon, and where would it drop to?
0:17:55 > 0:17:59Well, it would continuously drop.
0:17:59 > 0:18:03And that's what we're talking about. When you have enough energy
0:18:03 > 0:18:07to throw a rock or whatever it is to the horizon
0:18:07 > 0:18:11but you throw it hard enough that it then continuously falls,
0:18:11 > 0:18:12then you're in orbit.
0:18:12 > 0:18:15For a satellite to stay in the same place in the sky
0:18:15 > 0:18:18it has to travel at the same rate as the Earth spins -
0:18:18 > 0:18:21once every 24 hours.
0:18:21 > 0:18:24This is called geostationary orbit
0:18:24 > 0:18:31and it can only be achieved at 35,786km above the equator.
0:18:31 > 0:18:35Any closer to the Earth and the satellite orbits too fast.
0:18:35 > 0:18:38Any further away and it's too slow.
0:18:38 > 0:18:39And that's why, in the UK,
0:18:39 > 0:18:44all TV dishes point at 29 degrees above the horizon.
0:18:44 > 0:18:48They are all receiving a signal from one particular satellite
0:18:48 > 0:18:52that never moves in relation to our homes.
0:18:52 > 0:18:55Microwaves won't work round the curvature of the Earth.
0:18:55 > 0:18:56You need to be able to see the point
0:18:56 > 0:18:59that you're transmitting to or receiving from.
0:19:01 > 0:19:05The satellite receives and transmits signals through large antenna dishes
0:19:05 > 0:19:07that fold out from its main body.
0:19:11 > 0:19:15But they're very different from the dishes we see outside our homes.
0:19:16 > 0:19:21They have carbon fibre skins bonded onto a Kevlar honeycomb core,
0:19:21 > 0:19:24but there's another, more important difference -
0:19:24 > 0:19:27they don't have a smooth surface.
0:19:28 > 0:19:34The customers will specify a coverage. That coverage will be
0:19:34 > 0:19:39to maximise access to the population and the service area.
0:19:39 > 0:19:41So for the one we're looking at here,
0:19:41 > 0:19:45which is over Europe, we're looking at the landmass of Europe,
0:19:45 > 0:19:49so the more we can do to suppress the unwanted power over the sea,
0:19:49 > 0:19:52the more we can put it where they're going to get their revenue from.
0:19:52 > 0:19:56What we see in the top-right corner is what we're actually doing to the reflector.
0:19:56 > 0:20:00We're slowly manipulating the reflector surface, very subtly -
0:20:00 > 0:20:06in tens of millimetres - to actually produce a highly-concentrated area over Europe.
0:20:06 > 0:20:11Shaping the reflectors in this way focuses the signal better,
0:20:11 > 0:20:13and this is critical,
0:20:13 > 0:20:17because the power they transmit back to Earth is astonishingly small.
0:20:18 > 0:20:21The power that we're transmitting for each channel
0:20:21 > 0:20:24is equivalent to a 100-watt light bulb, and that 100-watt light bulb
0:20:24 > 0:20:29is 22,000 miles away from the surface of the Earth.
0:20:29 > 0:20:31This is quite amazing technology, really.
0:20:36 > 0:20:38The satellite is kept in its correct orbit
0:20:38 > 0:20:41with a series of different-sized engines,
0:20:41 > 0:20:46but given it weighs around six tonnes, it doesn't need the engines you may think.
0:20:46 > 0:20:50If you were to fit this engine to your car, you'd have trouble
0:20:50 > 0:20:53fitting in the three tonnes of propellant,
0:20:53 > 0:20:59but you may move it very, very slowly. It's not going to take off.
0:20:59 > 0:21:01But we're in space,
0:21:01 > 0:21:06so we can use this engine on a six-tonne satellite and move it
0:21:06 > 0:21:11through space because there's no friction, so it's relatively easy to do.
0:21:13 > 0:21:17Once in geostationary orbit, the smaller thrusters will take over
0:21:17 > 0:21:21from the main engine to keep the satellite in position.
0:21:21 > 0:21:25We have thrusters dotted around so that we can control
0:21:25 > 0:21:30the attitude of the satellite, to keep the antennas pointed, to keep the data flowing.
0:21:30 > 0:21:33We've got influences from the Earth, which is not a perfect sphere,
0:21:33 > 0:21:37so gravity will have an effect, and solar radiation from the sun.
0:21:37 > 0:21:42We have large solar arrays that will pick up from the solar radiation
0:21:42 > 0:21:45and slowly change the attitude of the satellite
0:21:45 > 0:21:48and we need to fire a thruster to bring it back.
0:21:52 > 0:21:55These manoeuvres happen regularly,
0:21:55 > 0:21:58just to keep the satellite in its correct position.
0:21:58 > 0:22:02But at the end of its life, these small thrusters will use
0:22:02 > 0:22:06the last of the fuel to blast it even further away from the Earth
0:22:06 > 0:22:11and into a graveyard orbit, which will be its final resting place.
0:22:17 > 0:22:21Whilst all the structural components for the satellite are built in Stevenage,
0:22:21 > 0:22:26the communications module is built in the company's other UK site at Portsmouth.
0:22:28 > 0:22:30Portsmouth's history is well-known,
0:22:30 > 0:22:35of course, for the maritime aspects of Portsmouth, but actually,
0:22:35 > 0:22:38for a long time, maybe associated with that
0:22:38 > 0:22:40there's been a capability
0:22:40 > 0:22:43in defence electronics.
0:22:45 > 0:22:50More than 50 years this site has been here, and over the last 20 years
0:22:50 > 0:22:54we've seen this shift from defence electronics to space.
0:22:57 > 0:23:00It's here that the electronic components
0:23:00 > 0:23:03that form the communications module are made and fitted.
0:23:05 > 0:23:10I don't think we talk about the space activities very much here.
0:23:10 > 0:23:12I don't know whether it was because it started off
0:23:12 > 0:23:15being defence-oriented and therefore quite secret,
0:23:15 > 0:23:18and whether that's sort of part of the culture.
0:23:18 > 0:23:22But nevertheless, people in this area don't normally associate it -
0:23:22 > 0:23:27even the ones that live here - don't know that we make sophisticated satellites.
0:23:27 > 0:23:30Over 12 months, thousands of individual electronic components
0:23:30 > 0:23:34will be designed, built and fitted to the structure.
0:23:36 > 0:23:39And their reliability is critical.
0:23:39 > 0:23:41Failure in space is not an option.
0:23:41 > 0:23:48Customers spend 150 million buying a satellite and if something
0:23:48 > 0:23:52goes wrong they are not happy and they don't come back to you again.
0:23:59 > 0:24:03This communication module is also known as the "payload".
0:24:03 > 0:24:05On a spacecraft there are many parts,
0:24:05 > 0:24:08but essentially it comes down to the payload -
0:24:08 > 0:24:09the reason for it being there,
0:24:09 > 0:24:13what it wishes to receive and what it wishes to transmit.
0:24:13 > 0:24:16Each satellite is guaranteed by the company
0:24:16 > 0:24:18to work for at least 15 years.
0:24:18 > 0:24:24If it doesn't, they don't get paid, so attention to detail is critical.
0:24:24 > 0:24:27The main driver for what we do here is reliability,
0:24:27 > 0:24:30so on the site here we have 3,000 engineers - no service engineers.
0:24:30 > 0:24:35Once the equipment on the spacecraft goes into service it has to operate
0:24:35 > 0:24:39for 15 years without any reduction in its quality of service.
0:24:39 > 0:24:41During that time, it gets hot and cold
0:24:41 > 0:24:47so the heat on board the spacecraft makes the electronics grow old.
0:24:47 > 0:24:49The radiation gives it sunburn,
0:24:49 > 0:24:52so it has to survive through all those things.
0:24:52 > 0:24:54At the heart of the communications module
0:24:54 > 0:24:57are micro-electronic circuits called "hybrids".
0:24:57 > 0:25:01These are computer processors, like silicon chips,
0:25:01 > 0:25:03but are built for space.
0:25:08 > 0:25:11The circuits are printed onto gallium arsenide,
0:25:11 > 0:25:15a semiconductor, and bonded onto a ceramic tile.
0:25:18 > 0:25:20Then they're connected with gold wire.
0:25:23 > 0:25:29I'm placing a one-thou gold wire onto a substrate
0:25:29 > 0:25:32using a combination of heat, pressure and vibration.
0:25:34 > 0:25:39Each satellite is made up of around 20kg of pure gold.
0:25:39 > 0:25:42It's 99.9% pure gold,
0:25:42 > 0:25:45so, yeah, it's good stuff!
0:25:46 > 0:25:48Only the best!
0:25:50 > 0:25:53Pure gold is stable, doesn't degrade
0:25:53 > 0:25:57and is an excellent conductor of both heat and electricity.
0:25:57 > 0:26:01I was only 18 when I first did wire bonding
0:26:01 > 0:26:03so I suppose I was quite adaptable to it.
0:26:03 > 0:26:06Even though I've got chubby fingers, I like doing delicate work.
0:26:09 > 0:26:11I haven't tried embroidery yet, though!
0:26:22 > 0:26:27Once complete, the chips are incorporated into bigger electronic units.
0:26:28 > 0:26:32I've been working on this for the best part of four years,
0:26:32 > 0:26:35to actually get it from the early design,
0:26:35 > 0:26:39right through to actually realising some of the hardware.
0:26:39 > 0:26:40Decoding commands -
0:26:40 > 0:26:45it's a bit like you sort of pick up your telephone and dial a number.
0:26:45 > 0:26:50This particular unit, crudely, it's doing the same sort of function.
0:26:54 > 0:27:00Then the components are tested again and again and again.
0:27:00 > 0:27:06We've got about 8,000 test steps on this particular unit on its own,
0:27:06 > 0:27:12so end to end, it's probably something like around two to three months, I would think.
0:27:12 > 0:27:16But certainly on the design side, you know, you're very conscious
0:27:16 > 0:27:19that this, actually, is going to be up there for 15 years.
0:27:19 > 0:27:24That's quite at the fore of your mind in terms of everything you do.
0:27:24 > 0:27:27It certainly is in my mind, anyway!
0:27:31 > 0:27:36But not all the components inside the satellite rely on modern technology.
0:27:40 > 0:27:44I've worked in this building for about 12 years,
0:27:44 > 0:27:49but I've been engaged on crystal growth for the last 42 years.
0:27:49 > 0:27:54- Morning, Mike.- Morning. - A huge problem for satellite communication is interference.
0:27:54 > 0:28:00This happens when the outgoing signal is confused with the incoming signal.
0:28:00 > 0:28:03This problem can be prevented by quartz crystals
0:28:03 > 0:28:07built into devices called "resonators".
0:28:08 > 0:28:12You can look on the quartz resonator as the beating heart.
0:28:12 > 0:28:18If the heart stops, the patient dies,
0:28:18 > 0:28:20and similarly, with a satellite,
0:28:20 > 0:28:26if the quartz crystal stops oscillating, the satellite will die.
0:28:28 > 0:28:34Oscillating crystals are used to control all the frequencies the satellite transmits.
0:28:36 > 0:28:38And the quality of the crystal is critical
0:28:38 > 0:28:42because if there's any impurity, they won't work.
0:28:42 > 0:28:46This is a block of natural quartz that we purchased from a small company
0:28:46 > 0:28:50that uses quartz for crystal balls.
0:28:50 > 0:28:55Something like that would set you back somewhere between £10,000-£20,000.
0:28:58 > 0:29:03- OK, Mike, bring in the crane. - Because Derek needs to ensure the crystal quality and supply,
0:29:03 > 0:29:06he originally used purchased crystals
0:29:06 > 0:29:09to provide seeds from which he grows his own.
0:29:14 > 0:29:17What we're trying to do here is to replicate the way
0:29:17 > 0:29:19natural quartz grows in nature.
0:29:19 > 0:29:23Natural quartz will grow deep in the Earth's crust. The difference
0:29:23 > 0:29:27is we're trying to speed up the process so we can complete
0:29:27 > 0:29:31the growth in, essentially, a few months rather than a few thousand years.
0:29:33 > 0:29:36Over the next three months, under a high temperature
0:29:36 > 0:29:41and enormous pressure, crystals slowly form in a solution of caustic soda.
0:29:41 > 0:29:44We've been producing them for 25 years or so,
0:29:44 > 0:29:46and so far nobody has beaten them.
0:29:51 > 0:29:54Once they're formed, the pure crystals are first sliced...
0:29:57 > 0:29:58..then shaped...
0:30:00 > 0:30:03..and finally polished
0:30:03 > 0:30:05until they are little bigger than a contact lens
0:30:05 > 0:30:09before being incorporated into the satellite's electronics.
0:30:09 > 0:30:11Our crystals are the purest in the world.
0:30:11 > 0:30:13I can say that with absolute certainty.
0:30:23 > 0:30:27Once all the electronic sections have been made,
0:30:27 > 0:30:30they need to undergo a series of tests before being attached
0:30:30 > 0:30:32to the communications module.
0:30:32 > 0:30:35My name's Gary Stancombe. I've worked in vibration tests
0:30:35 > 0:30:39and mechanical tests at Astrium for 15 years now.
0:30:39 > 0:30:43I'm going to do some taping down to tidy it up and then we'll be ready.
0:30:43 > 0:30:45OK.
0:30:48 > 0:30:54This test is to check they will survive the extreme physical impact of the satellite's launch.
0:30:54 > 0:30:58What we're doing today is we're going to subject this unit
0:30:58 > 0:31:02to a sequence of vibration tests to simulate the launch environment
0:31:02 > 0:31:07when the rocket lifts off and those eight minutes which will take it into space.
0:31:09 > 0:31:17It does get a fair old shake. Today, we're going to subject it to a 20G vibration test -
0:31:17 > 0:31:2320 times gravity. So anything in there will feel 20 times heavier.
0:31:24 > 0:31:27Every electronic component is tested in this way,
0:31:27 > 0:31:30sometimes to breaking point.
0:31:30 > 0:31:33It is a hard test, yeah. It's a thorough test.
0:31:35 > 0:31:38It has to be. We have to ensure that everything
0:31:38 > 0:31:43is going to still be working once the unit gets into space.
0:31:43 > 0:31:46We do see failures, but not too often.
0:31:49 > 0:31:53But it's not just the vibration of the launch that each component has to cope with.
0:31:53 > 0:31:56There are also massive shock waves.
0:31:56 > 0:32:01These happen as explosive charges decouple each stage of the rocket.
0:32:01 > 0:32:04From the solid boosters, the satellite housing
0:32:04 > 0:32:09and main engine, through to the deployment of the satellite itself.
0:32:09 > 0:32:13These are quite substantial shock waves so they need to be tested.
0:32:19 > 0:32:21OK, and that's the shock test!
0:32:24 > 0:32:28Once the electronics have survived all these tests
0:32:28 > 0:32:31they can be fitted into the communications module.
0:32:34 > 0:32:39Ian Kilby started work as a technician over a decade ago,
0:32:39 > 0:32:44but he's now in charge of ensuring everything is connected correctly.
0:32:44 > 0:32:48When I moved up from technician to engineer, at that point
0:32:48 > 0:32:51you're no longer allowed to fit any equipment to the payload.
0:32:51 > 0:32:55I do miss the hands-on side of things.
0:32:55 > 0:32:58I used to enjoy the challenges that wave-guide
0:32:58 > 0:33:00and co-ax present to the fitters,
0:33:00 > 0:33:02and yeah,
0:33:02 > 0:33:07sometimes I do wish, on particularly bad days, I wish I was back down there
0:33:07 > 0:33:11on the tools and could not worry so much about things.
0:33:13 > 0:33:16At the moment, the communications module is in two pieces
0:33:16 > 0:33:21and Ian has a brave attempt at explaining how it all fits together.
0:33:21 > 0:33:25Basically the signal, when it's received from Earth -
0:33:25 > 0:33:27when the whole satellite's coupled -
0:33:27 > 0:33:32there'll be an antenna, a receiver antenna on the top floor.
0:33:32 > 0:33:35The signal will come in. It goes through the equipment on the top floor.
0:33:35 > 0:33:38They amplify it, clean up the signal,
0:33:38 > 0:33:42get the part of the signal we require.
0:33:42 > 0:33:46It then travels down, down through the payload and there will be
0:33:46 > 0:33:49some equipment called MPMs which are not installed yet.
0:33:49 > 0:33:53It travels up through the switch network, goes up through the OMUX,
0:33:53 > 0:33:59it's amplified again and harmonised a little bit more, the signal is cleaned
0:33:59 > 0:34:03a little bit more again at the OMUX level, and then basically, it comes back
0:34:03 > 0:34:08to the top floor, to a feed-horn, to the reflector and then back to Earth.
0:34:10 > 0:34:13Ian's idiots' guide to a payload!
0:34:13 > 0:34:19Modern telecom satellites can now transmit over 300 digital channels simultaneously.
0:34:21 > 0:34:25But just 20 years ago, they could only cope with ten analogue TV channels.
0:34:27 > 0:34:29And their speed of transmission, or lack of it,
0:34:29 > 0:34:31was apparent to everyone.
0:34:31 > 0:34:34THEME MUSIC
0:34:37 > 0:34:42If you think back to Terry Wogan's show, when he used to have one on BBC One...
0:34:45 > 0:34:49..the very first sort of satellite links, London to New York,
0:34:49 > 0:34:51it was almost painful to watch.
0:34:51 > 0:34:54She called me, did she?
0:34:54 > 0:34:57# I hear you calling me. #
0:34:57 > 0:35:00- Am I speaking to Linda Gray? - HIS WORDS ECHO:- ..Linda Gray.
0:35:00 > 0:35:03- Yes.- Well, that's established that it's not working.
0:35:03 > 0:35:05SHE LAUGHS
0:35:05 > 0:35:09With the amount of lag, you had to wait for the signal to go,
0:35:09 > 0:35:13or Terry's voice to reach the USA, and then the response time back.
0:35:13 > 0:35:16It was an eternity. I'm sure people remember that.
0:35:16 > 0:35:18It just took forever.
0:35:18 > 0:35:21When we talk on satellite like this, you know, the miracle of sound,
0:35:21 > 0:35:24there's just a little second or two delay.
0:35:24 > 0:35:27So it's not that Barry's hearing has gone.
0:35:27 > 0:35:29It's merely it's a long way to Los Angeles.
0:35:29 > 0:35:33But now with the speed, the processing power and the speed
0:35:33 > 0:35:38of modern satellites, it's barely noticeable. It's, like I say, within a second.
0:35:43 > 0:35:47Once all the electronic equipment is fixed, the side panels
0:35:47 > 0:35:51and the central structure are joined together to form the complete communications module.
0:35:51 > 0:35:56These are some of the most delicate parts of the satellite.
0:35:58 > 0:36:03And to safeguard them in the extreme environment of deep space, they need special protection.
0:36:06 > 0:36:08My name's Katy Smith.
0:36:08 > 0:36:09I'm the thermal architect here
0:36:09 > 0:36:12and I've been working here for about six years.
0:36:14 > 0:36:19My job is the thermal design, the build, the test of the spacecraft.
0:36:22 > 0:36:24Deep-space environment's incredibly hostile.
0:36:24 > 0:36:27It's incredibly cold - minus-270 degrees C -
0:36:27 > 0:36:32whereas the sun-pointing surface could be in the region of 150, if not more.
0:36:32 > 0:36:36And on top of that, you're in a vacuum so there's no convective environment,
0:36:36 > 0:36:38you can't reject heat like you would.
0:36:38 > 0:36:42For example, your cup of tea, when you blow on it, it removes the heat. It doesn't exist.
0:36:42 > 0:36:48And the satellite needs to be able to operate within these massive temperature differences.
0:36:48 > 0:36:52If we sent a spacecraft up into space with no insulation,
0:36:52 > 0:36:54it wouldn't work.
0:36:54 > 0:36:58You'd have one side with severe damage to the structure because of the sun's influence.
0:36:58 > 0:37:03You'd have panels dropping off. So the distortions caused by the temperature differences
0:37:03 > 0:37:06would buckle the structure and destroy it.
0:37:06 > 0:37:10And the heat isn't just a problem on the outside of the satellite
0:37:10 > 0:37:12because these extremes of temperature could be
0:37:12 > 0:37:16disastrous for all the on-board electronics inside.
0:37:16 > 0:37:20They can only operate between a cold minus-10 degrees
0:37:20 > 0:37:22to a warm 40 degrees.
0:37:23 > 0:37:26So to keep the internal temperature within this range,
0:37:26 > 0:37:32- the satellite is wrapped in material called Kapton. - Kapton is a high-temperature layer.
0:37:32 > 0:37:36It's very robust. You can use it in an environment from minus-250 degrees C,
0:37:36 > 0:37:40up to a continuous operating temperature of about 290 degrees C.
0:37:40 > 0:37:45I think the best way of describing it as a home product would be a Quality Street wrapper.
0:37:45 > 0:37:48It's difficult to tear, incredibly light,
0:37:48 > 0:37:51so for a space environment, it's hugely applicable.
0:37:51 > 0:37:56But Kapton can't protect the satellite on its own.
0:37:56 > 0:38:00What you're actually seeing here is a very thin deposition of aluminium.
0:38:00 > 0:38:05So here, when you can see the gold outer layer, it's not actually gold.
0:38:05 > 0:38:08What you're seeing is the vacuum-deposited aluminium
0:38:08 > 0:38:13behind the Kapton, like that, giving it an amber or gold effect.
0:38:16 > 0:38:21The aluminium-backed Kapton forms a blanket, insulating the satellite
0:38:21 > 0:38:25and preventing heat being lost to deep space, while at the same time
0:38:25 > 0:38:29stopping the sun overheating the electronics inside.
0:38:32 > 0:38:34I know it seems kind of counterintuitive
0:38:34 > 0:38:37because you've got large amounts of energy coming in from the sun,
0:38:37 > 0:38:40but to balance it out and find a happy medium,
0:38:40 > 0:38:43you have to block some of the sun, dump some of the heat
0:38:43 > 0:38:48and supply some heat internally. It's a really complicated juggling act.
0:38:49 > 0:38:53The Kapton blanket is the first line of defence at keeping
0:38:53 > 0:38:56the satellite at a reasonably constant temperature.
0:38:56 > 0:39:00But the electronics inside also create their own heat,
0:39:00 > 0:39:02and this, too, needs to be dissipated.
0:39:04 > 0:39:07To do this, some very clever engineering
0:39:07 > 0:39:10is also incorporated into the two large structural panels
0:39:10 > 0:39:12on the outside of the service module.
0:39:17 > 0:39:23A complex matrix of pipes act as massive radiators, dumping heat generated by the electronics
0:39:23 > 0:39:26and keeping the internal temperature constant.
0:39:27 > 0:39:33A heat pipe is a very, very effective method of moving heat from one local region to another.
0:39:33 > 0:39:36There's no working parts, no electricity required,
0:39:36 > 0:39:38so power-wise, it's good.
0:39:39 > 0:39:44But unlike household radiators, these pipes contain ammonia,
0:39:44 > 0:39:48because it boils and vaporises at just the right temperature -
0:39:48 > 0:39:5033 degrees centigrade.
0:39:52 > 0:39:55So what happens, is at one end,
0:39:55 > 0:39:57in the hot, high power dissipation region,
0:39:57 > 0:40:00what will be a liquid at that stage evaporates.
0:40:00 > 0:40:03The vapour then travels up the tube, up the centre of the tube
0:40:03 > 0:40:06to the cold region and at this region it condenses.
0:40:06 > 0:40:08It dumps the heat and then travels back down
0:40:08 > 0:40:11to start the whole cycle again in the form of a liquid.
0:40:16 > 0:40:19There is one final line of defence,
0:40:19 > 0:40:22which is also crucial in reflecting heat away from the satellite.
0:40:24 > 0:40:27And it's all down to this team.
0:40:29 > 0:40:31I know it sounds very cheesy,
0:40:31 > 0:40:33but it's the satisfaction of knowing
0:40:33 > 0:40:36that you're actually contributing to mankind.
0:40:36 > 0:40:39You see that panel that comes in with no mirrors on it.
0:40:39 > 0:40:42And then, when it goes out, it looks beautiful, all polished up.
0:40:42 > 0:40:46And you know it's serving a purpose up there to protect the spacecraft.
0:40:46 > 0:40:49You stand back and look at it and go, "Wow, we did that."
0:40:51 > 0:40:56A thin silver surface of mirrors will reflect the sun's rays
0:40:56 > 0:41:00away from the satellite and is its last form of heat defence.
0:41:02 > 0:41:04These are 100 microns thick.
0:41:04 > 0:41:06So they are very thin, it's about as thick as a human hair.
0:41:06 > 0:41:11We have sheets of 198 mirrors at a time, so they're very fragile.
0:41:12 > 0:41:15The glass the mirrors are made of also helps to emit heat
0:41:15 > 0:41:17away from its core.
0:41:17 > 0:41:19Just want to feather that in.
0:41:19 > 0:41:23Well, we've put the activator in and we've only got 30 minutes
0:41:23 > 0:41:29to apply the adhesive, put the mirrors on and get it under vacuum,
0:41:29 > 0:41:30So, it is a bit of a rush.
0:41:31 > 0:41:38It's eight hours of prep for 30 minutes of organised chaos!
0:41:38 > 0:41:42The surface that you can see is 99% silver,
0:41:42 > 0:41:44it's pure silver.
0:41:44 > 0:41:48And the back surface, the darker side, is nickel and chrome,
0:41:48 > 0:41:50which is called nichrome
0:41:50 > 0:41:53and that is there purely to stop the silver from oxidising.
0:41:53 > 0:41:56I you remember, if you can think back
0:41:56 > 0:41:59to your grandmother's silver dinner service when it goes black.
0:41:59 > 0:42:02These will go black and they then, they don't become reflective.
0:42:06 > 0:42:08That's it. We're done.
0:42:12 > 0:42:16In Portsmouth, Ian Kilby is putting the communications module
0:42:16 > 0:42:17through its final checks
0:42:17 > 0:42:20in a special room called an anechoic chamber.
0:42:21 > 0:42:23We're firing some microwaves at the payload
0:42:23 > 0:42:27to see if there are any leaks in any of our co-axial connections.
0:42:27 > 0:42:31So, if you imagine the same signal is inside the payload,
0:42:31 > 0:42:34it's leaked around and it's coming out of a hole,
0:42:34 > 0:42:38it could, in turn, effect the input into the satellite
0:42:38 > 0:42:40and the output going out.
0:42:40 > 0:42:42So, it could blind itself, in effect,
0:42:42 > 0:42:44with its own loop of RF signal.
0:42:46 > 0:42:49It's been quite catastrophic in the past to have EMC leaks
0:42:49 > 0:42:52because it actually interferes with the transmission
0:42:52 > 0:42:54that's coming from the comms module back to Earth.
0:42:54 > 0:42:58The chamber is designed to block out any radio signals
0:42:58 > 0:43:00from getting in or out.
0:43:00 > 0:43:03It's almost like taking a telephone towards a radio
0:43:03 > 0:43:06when you're phoning the radio station.
0:43:06 > 0:43:11You get that a big screaming squeal, in an effect not a screaming squeal,
0:43:11 > 0:43:15but obviously it has a similar effect on a telecoms payload.
0:43:16 > 0:43:18With the final testing complete,
0:43:18 > 0:43:21it's time to box up the communications module
0:43:21 > 0:43:22ready for shipping.
0:43:22 > 0:43:26It's always a nerve-wracking moment to pick up something of this value.
0:43:26 > 0:43:30It's all the fruits of our labours over the last few months.
0:43:30 > 0:43:32Lots of things potentially could go wrong.
0:43:32 > 0:43:35You know, we're picking it up with a crane.
0:43:35 > 0:43:38Failure with the crane or something catastrophic could happen.
0:43:38 > 0:43:41Even when it's turning into the box, it's quite a nerve wracking moment,
0:43:41 > 0:43:46it's quite a large mass.
0:43:46 > 0:43:49After over two years of intense and complicated engineering,
0:43:49 > 0:43:52most of the work that takes place in the UK is done
0:43:52 > 0:43:57and the modules are shipped to Toulouse in the south of France.
0:43:57 > 0:44:02It's always quite pleasing when you see another delivery going out of the door.
0:44:02 > 0:44:07It's in this facility where the final assembly happens.
0:44:07 > 0:44:11It's a complicated and delicate process.
0:44:11 > 0:44:14First, the service module made in Stevenage
0:44:14 > 0:44:18and the communications module from Portsmouth will be joined together.
0:44:18 > 0:44:21Then, the solar arrays are added.
0:44:21 > 0:44:24Finally, the antenna will be attached.
0:44:31 > 0:44:34Graham Viney has escorted the service module to Toulouse
0:44:34 > 0:44:37but luckily for him it's his French colleague,
0:44:37 > 0:44:40Pascal Gaudin, who's in charge.
0:44:40 > 0:44:41This phase is key for Pascal,
0:44:41 > 0:44:44he's responsible for the integration here.
0:44:44 > 0:44:50For me, you can probably tell I'm a little more relaxed,
0:44:50 > 0:44:56but I understand what Pascal is going through, but it's not me.
0:44:56 > 0:44:57Here, at that point,
0:44:57 > 0:45:02we have a few millimetres, really, tolerance, that's all.
0:45:03 > 0:45:07We are all feeling a bit nervous about this
0:45:07 > 0:45:11because we have to look at all the proximities
0:45:11 > 0:45:13between the two structures
0:45:13 > 0:45:18and spacecraft is never the same, so each time there are surprises,
0:45:18 > 0:45:22so, we have to be very careful about this operation.
0:45:24 > 0:45:28After six hours careful work, the two British built modules are successfully coupled
0:45:28 > 0:45:33and the main body of the satellite is complete.
0:45:33 > 0:45:34I think more relaxed,
0:45:34 > 0:45:37we passed the most critical phase of this operation.
0:45:37 > 0:45:41Now we still have to fit all together the different interfaces,
0:45:41 > 0:45:45which are on different levels
0:45:45 > 0:45:48but so far it's a success,
0:45:48 > 0:45:51yes, this coupling is a success.
0:45:54 > 0:45:58Completing the satellite in Toulouse will take another seven months
0:45:58 > 0:45:59of dedicated work.
0:46:04 > 0:46:07Although all satellites carry fuel for the engines
0:46:07 > 0:46:09they are actually solar powered.
0:46:15 > 0:46:17My name is Ludwig Grandl,
0:46:17 > 0:46:24I am the manager for the Centre Of Competence of Astrium Solar Arrays,
0:46:24 > 0:46:25here in Germany.
0:46:27 > 0:46:31For the last 40 years, the main centre for solar array production
0:46:31 > 0:46:33in Europe has been this factory.
0:46:37 > 0:46:41The satellite will have over 20,000 individual solar cells,
0:46:41 > 0:46:45each helping to generate the electricity needed
0:46:45 > 0:46:47to power the electronic systems.
0:46:51 > 0:46:54What you can see here, that's a typical solar array
0:46:54 > 0:46:57for our Euro star programmes.
0:46:57 > 0:47:01One wing as we see it here completed with the mechanism
0:47:01 > 0:47:03is around 130kg.
0:47:05 > 0:47:08Though, on a satellite we have two of them.
0:47:09 > 0:47:14Each array is 20 metres long and yet their combined total weight
0:47:14 > 0:47:17is the equivalent of just three average sized men.
0:47:20 > 0:47:21The arrays are folded
0:47:21 > 0:47:24against the satellite's structure for the launch,
0:47:24 > 0:47:26but once in space, they gently unfold,
0:47:26 > 0:47:29using a system of springs and wires.
0:47:31 > 0:47:35Let me say, we are extreme reliable in this way
0:47:35 > 0:47:41and we never lost function of one of our solar arrays
0:47:41 > 0:47:42for whatever reasons.
0:47:44 > 0:47:47The solar arrays are dependent on a drive mechanism.
0:47:49 > 0:47:53This allows them to move and always face the sun
0:47:53 > 0:47:58and this machine has been designed and built back in the UK
0:47:58 > 0:48:00by Bob and his team.
0:48:00 > 0:48:03This is one of the key critical elements in the spacecraft,
0:48:03 > 0:48:07so it has to operate every day for 15 years.
0:48:07 > 0:48:10If we lose this, we lose power into the spacecraft,
0:48:10 > 0:48:12that causes the mission failure.
0:48:12 > 0:48:16This mechanism is one of the most critical components
0:48:16 > 0:48:18of the whole satellite.
0:48:18 > 0:48:21It has to move the solar arrays to face the sun every second
0:48:21 > 0:48:26of every day for its entire 15 year lifetime.
0:48:26 > 0:48:30Because if it doesn't, the satellite will loose power.
0:48:30 > 0:48:31This provides two functions.
0:48:31 > 0:48:34It provides the power transfer from the arrays
0:48:34 > 0:48:36and then it also enables the arrays to track the sun
0:48:36 > 0:48:38by rotating at one cycle per day.
0:48:38 > 0:48:41This is the spacecraft. These are the arrays.
0:48:41 > 0:48:44So, they sit in here holding the arrays
0:48:44 > 0:48:47and if you imagine my fist as the Earth
0:48:47 > 0:48:50and the camera perhaps as the sun,
0:48:50 > 0:48:53then as the Earth rotates and the spacecraft rotates,
0:48:53 > 0:48:59you'll see that if you don't rotate the array to track the sun,
0:48:59 > 0:49:01then you don't get the power.
0:49:01 > 0:49:04So we have to rotate, as this space craft sits
0:49:04 > 0:49:08in geostationary orbit above the equator, moving round the Earth,
0:49:08 > 0:49:11we have to rotate these so they are always facing the sun.
0:49:14 > 0:49:17There is a very, very high pleasure in engineering
0:49:17 > 0:49:19in getting something right.
0:49:19 > 0:49:21The fact that you can see something which was,
0:49:21 > 0:49:25in effect, something in somebody's imagination turn into reality
0:49:25 > 0:49:30and for it then to be successful, is a tremendous kick, it really is.
0:49:37 > 0:49:41With everything fitted and tested the satellite is carefully packed
0:49:41 > 0:49:44into a hi-tech crate and sent by plane to the launch site...
0:49:49 > 0:49:52..Where it's prepared for its final journey.
0:49:57 > 0:50:00It's a tense time for the whole team.
0:50:05 > 0:50:09We're in the satellite control centre and this control centre
0:50:09 > 0:50:12takes over control of the satellite
0:50:12 > 0:50:14after it's separated from the launcher.
0:50:14 > 0:50:16It is critical, it is a crucial phase.
0:50:16 > 0:50:20Good line pressure to fire the thrusters.
0:50:23 > 0:50:27At the moment, this team here is running through a rehearsal.
0:50:27 > 0:50:31There is a computer simulating everything the satellite does,
0:50:31 > 0:50:35we can send commands as we would and it responds like a satellite,
0:50:35 > 0:50:38and it's really testing, testing the team.
0:50:39 > 0:50:42As the satellite is being prepared for launch
0:50:42 > 0:50:46on the other side of the world, these rehearsals are critical
0:50:46 > 0:50:49because when it leaves the rocket that gets it into space
0:50:49 > 0:50:51its orbit will be elliptical.
0:50:53 > 0:50:58The moments leading up to the firing of that main engine is very tense,
0:50:58 > 0:50:59a lot of pressure,
0:50:59 > 0:51:03and if it doesn't happen we have a lot of people looking at us.
0:51:04 > 0:51:09Graham and his team will then have to fly it into the correct geostationary orbit
0:51:09 > 0:51:13by remotely operating its main engine and thrusters.
0:51:15 > 0:51:19Each burn will take up to 90 minutes, but overall
0:51:19 > 0:51:24the procedure will take two weeks and use half of the available fuel.
0:51:24 > 0:51:28Every time we circularise the orbit of a satellite, there's something
0:51:28 > 0:51:33about those two weeks where something will challenge us.
0:51:40 > 0:51:43The launch day is fast approaching.
0:51:43 > 0:51:45And over 4,000 miles from Stevenage,
0:51:45 > 0:51:48Bob Graham is following the satellite's journey.
0:51:48 > 0:51:51We're in French Guiana, which is in South America
0:51:51 > 0:51:53and very close to the equator.
0:51:55 > 0:51:58Green, lots of green trees.
0:51:58 > 0:52:01Very, very hot, about 37 degrees today.
0:52:02 > 0:52:06One of the reasons we launch from the equator, or very close to the equator,
0:52:06 > 0:52:10is because the earth spins
0:52:10 > 0:52:14and there's a faster rotational speed actually on the equator.
0:52:17 > 0:52:21It makes business sense to fire a rocket into space from the equator
0:52:21 > 0:52:23as it's cheaper to launch.
0:52:23 > 0:52:26Which means less fuel, means a lower cost launch
0:52:26 > 0:52:29and from the spacecraft's perspective
0:52:29 > 0:52:33it's actually being placed closer to its end orbital position
0:52:33 > 0:52:36so, again, it uses less fuel on the spacecraft.
0:52:39 > 0:52:44The satellite will be lifted into orbit by an Ariane 5 rocket.
0:52:44 > 0:52:49At over 50 metres and almost 800 tonnes fully fuelled,
0:52:49 > 0:52:52this is the workhorse of European space exploration.
0:52:59 > 0:53:03Our satellite is right at the top of the launch vehicle
0:53:03 > 0:53:05you can see the fairing at the top the curved part
0:53:05 > 0:53:10is literally sitting right inside there.
0:53:10 > 0:53:13Watching the launch has a special resonance for Bob.
0:53:13 > 0:53:17I've worked in the space industry for nearly 30 years,
0:53:17 > 0:53:21never seen a launch in my whole career, never.
0:53:22 > 0:53:27To be so close is a really incredible and moving moment
0:53:27 > 0:53:32because a lot of people do not actually get to witness this.
0:53:32 > 0:53:34I feel terribly privileged that I'm here
0:53:34 > 0:53:37and I would see myself as a representative of the people
0:53:37 > 0:53:42who've actually contributed to the delivery and the success of this spacecraft.
0:53:43 > 0:53:48You're talking about 30 million horsepower at launch.
0:53:48 > 0:53:51So, the thrust when this vehicle takes off
0:53:51 > 0:53:55is about the equivalent of 12 A380 airbuses taking off.
0:53:55 > 0:53:57This is a pretty rough ride for the satellite
0:53:57 > 0:54:00and that's what all the design and everything is about.
0:54:00 > 0:54:03We have to make sure it survives this phase
0:54:03 > 0:54:05and then it can go into operation.
0:54:05 > 0:54:07So, it's, er, yes,
0:54:07 > 0:54:11this is the bit where we all get that...little bit of butterflies in the stomach,
0:54:11 > 0:54:14which is saying, "I hope this goes all right."
0:54:14 > 0:54:17Maybe even some sweaty palms, let's wait and see.
0:54:22 > 0:54:23Later that day,
0:54:23 > 0:54:27the rocket is carefully rolled out to the launch pad.
0:54:27 > 0:54:31It's taken over two years, in excess of £100 million
0:54:31 > 0:54:35and some exceptional engineering to get this far.
0:54:36 > 0:54:39And now, there's nothing Bob can do.
0:54:39 > 0:54:40Except wait.
0:54:52 > 0:54:54Launch day.
0:54:54 > 0:54:57And on schedule, the automatic countdown commences.
0:55:03 > 0:55:07At first, everything goes smoothly.
0:55:12 > 0:55:18But at just 1 minute and 47 seconds before ignition,
0:55:18 > 0:55:19the countdown stops.
0:55:22 > 0:55:25The window has opened and there's a hold.
0:55:25 > 0:55:28There's some problem somewhere which they're checking.
0:55:28 > 0:55:30They'll restart the seven-minute countdown.
0:55:30 > 0:55:32So we will see how it goes from here.
0:55:34 > 0:55:38Little butterflies. Is it going to go? Is it going to go?
0:55:38 > 0:55:41And is it going to be...
0:55:42 > 0:55:46..as they say it is in terms of the light, the noise
0:55:46 > 0:55:48and, er...yeah.
0:55:48 > 0:55:50So let's see.
0:55:50 > 0:55:53As night falls, it's apparent that the technical issues
0:55:53 > 0:55:56are more serious than first thought.
0:55:57 > 0:56:02And after an hour of waiting, the launch is cancelled.
0:56:13 > 0:56:16The next morning, an initial investigation suggests
0:56:16 > 0:56:20a faulty fuel valve in the rocket caused the postponement.
0:56:23 > 0:56:27Here we are in Mission Control Jupiter, the morning after.
0:56:28 > 0:56:32This is the place where that final decision was made last night
0:56:32 > 0:56:33to postpone it.
0:56:37 > 0:56:40As an engineer, I know this is the right decision.
0:56:40 > 0:56:44The decision made last night was the right one. But...
0:56:45 > 0:56:48..as a man, as a person, as a representative of a team,
0:56:48 > 0:56:52yes, there's an element of disappointment that it didn't happen.
0:56:54 > 0:56:57Space is difficult. It is about risk.
0:56:57 > 0:57:00It is about showing that our products are good,
0:57:00 > 0:57:04but we can't afford to take the risks. But it will happen again.
0:57:04 > 0:57:08Maybe I won't see it, but others will and I guess that's life.
0:57:21 > 0:57:25And finally, the satellite was successfully launched.
0:57:47 > 0:57:53Today, 35,786 kilometres above us,
0:57:53 > 0:57:56the brand-new communications satellite
0:57:56 > 0:58:01is now being prepared to broadcast pictures directly into your home.
0:58:02 > 0:58:04So keep watching the skies.
0:58:08 > 0:58:12From sketch to structure, see how designs come to life by visiting:
0:58:16 > 0:58:19And follow the links to the Open University.
0:58:44 > 0:58:48Subtitles by Red Bee Media Ltd
0:58:48 > 0:58:51Email subtitling@bbc.co.uk