A Satellite How to Build...

It must be right first time.

You can't service it or bring it back

or complain to the manufacturer that it doesn't work.

Failure in space is not an option. If something goes wrong,

customers are not happy and they don't come back to you again.

So what we've got here

is the startings of a telecommunications satellite.

We've got seven smaller thrusters and we have a main engine,

which is fitted inside the cone.

If we sent a spacecraft up into space with no insulation,

the distortions caused by the very temperature differences

would buckle the structure and destroy it.

If the heart stops, the patient dies.

If the quartz crystal stops oscillating, the satellite will die.

If I say I work on satellites...

"What, you put the dishes on the walls, do you?"

They just don't... They don't understand

that there's something up there as well, in space.

The moments leading up to the firing of that main engine is very tense.

It's the nearest we get to science fiction.

It's just something people dream of. We sort of live a little bit of that dream.

Space is incredibly special. What we do is quite exceptional here.

After almost two years of precision engineering

and costing over £100 million,

a six-tonne telecommunications satellite

is sitting on top of this rocket.

In terms of the satellite,

the risk here of course is that it's now about to be shaken

from the rocket motors.

It's also going to get a fantastic thrust load on it.

And now it's just one day away from being fired into orbit.

The amount of testing that we do to verify it effectively

never guarantees you 100% but it guarantees you that you've got

a very, very high probability of success and that's what we go for.

The violence of the launch is the most dangerous moment

of a satellite's life.

We have to make sure it survives this phase

and then it can go into operation.

This is the bit where we all get that, er...

A little bit of butterflies in the stomach.

And although it's being launched in faraway French Guiana,

most of it was designed and built in Britain.

We're on the A1 heading south at the moment.

It's about quarter to eight in the morning.

I've done this trip for the last 30 years.

Bob Graham is a site director at Astrium,

one of the biggest spacecraft manufacturers in the world.

If people say, "Who do you work for?"

and I mention the name of the company

there's often a slightly quizzical look on their face.

Then it becomes quite a surprise when you say,

"Well, I work in the space industry."

When the Space Race was at its height in the 1960s,

the United Kingdom had virtually no space industry.

Today, British engineers lead the world in satellite design

and manufacture.

Working in space is always something different

and there's not many people in the industry.

So in the pub when someone says, "What do you do for a living?"

You say, "I work in the space industry,"

they do give you a funny look.

We watched the moon landings

and everything that NASA did was quite incredible.

For me, I can't quite believe I'm being able to do this.

Yeah, we've known each other a long time.

26 years? Haven't we?

Is it that long?

-I think so.

-God.

-Yeah.

-Oh, dear.

We don't look that old either, do we?

What's Mr Cross up to? You visitors are all the same!

Astrium have factories all across Europe

but employ around 3,500 people in the UK.

Every satellite the company builds starts life here

just outside London on their site in Stevenage.

I've worked here for nearly 30 years.

I came to Stevenage in 1982 for what was sold to me

as a 12-18 month position and I've been here ever since.

It gets into your blood.

It's a really, really good job to have.

There's not many areas within in the country

where you can actually work on spacecraft.

Telecommunication satellites are an integral part of the modern world.

They allow us to send television pictures and communicate

over vast distances using all of today's modern technology.

But because they operate in deep space,

they have to incorporate some extremely complex engineering.

A modern communications satellite needs to be capable of surviving

the possible impact of debris

travelling at thousands of metres per second.

And they need to be able to operate in temperatures that fluctuate

between minus 200 degrees Centigrade

to a blistering 150 degrees Centigrade.

And yet, the satellite has to continuously operate

for a guaranteed 15 years, because out in space,

there's absolutely no prospect of repair.

I think people do take it for granted.

So if you pick up your mobile phone to make a phone call

you don't realise it's bouncing off a satellite. Or you turn on your TV.

It's just stuff you do everyday without thinking about it.

-The upper quadrant, section five...

-Yeah?

-..looked fine.

A modern telecommunications satellite

can be over five metres high and three metres wide.

Although astonishingly complicated,

there are basically two distinct parts forming its main body.

The mechanics...

and the electronics.

The mechanics make up what's called the service module.

And the electronics make up the communications module.

The satellite's central skeleton is built around a carbon fibre cylinder

connected to aluminium panels which hold four fuel tanks,

a main engine, thrusters and batteries.

This is the service module.

On top of it sits the communications module

which carries the satellite's complex electronic payload.

Also added are solar arrays.

Attached to the main body, they capture sunlight

which is converted into electric power, and antenna dishes

that will transmit and receive signals from Earth.

And by looking at different stages of the build

it's possible to understand how they're put together.

From the manufacturing viewpoint

this is the beginning of the process.

The build begins with a central core, the skeleton of the satellite.

Strands of carbon fibre coated with resin

are wound into a complex pattern to make the cylinder

as strong and light as possible.

When it's finished and vertical it weighs just 20kg

and is ready for the next stage of construction.

In here is where we produce our panels, our honeycomb panels.

Aluminium skins. Very, very thin skins, very lightweight.

Low mass is key in terms of space

and we use aluminium because it's good structurally.

The aluminium panels are attached to the central cylinder

forming more of the basic structure.

John Richards has been building these

for almost his whole working life.

We're just putting the flight bolts into the SM floor

and that attaches the floors to the central structure.

I'm not sure how many bolts, probably about 20 in each quadrant.

I don't suppose, really, people just think of satellites

as something that's up in space orbiting round.

I don't suppose they think of actually what goes into building them.

You take your time, because as you're probably aware

that these things are worth a lot of money.

And it only takes us to make one slight mistake

and it could end up costing millions of pounds.

Best thing about working here is the people like John and people that have been here years,

always willing to pass on experience and to help you out.

After the basic structure is finished

the rest of the systems can be added.

Once I've gone through my final testing we have a big clean down,

make sure it's particle free, ready to be accepted

into Mick's area and I'll give him a shout and usually that's it.

I mean it's very casual, it's just, "When you going to be ready?"

"Tomorrow", whatever, and just hand it over to him.

Satellites have to be built in extremely clean environments

because any dirt inside the moving parts can have devastating effects

once they're in space.

In fact there are special areas of the factory that actually have fewer

dust particles than you'd find in a typical hospital operating theatre.

And in here, engineer Graham Viney and team leader Mick Atkinson

have the tricky task of managing the assembly and integration

of the fuel tanks, the pipe work and the engines of the service module.

We do get problems now and again because when it's designed,

it's all done on a model and then when it comes down to us

it is quite a bit different in the real life, putting it together.

There's certain things that we know we can't do in the design

because it just won't be able to be done on the shop floor.

So what we've got here is the overall service module

or the startings of the service module of the telecommunications satellite.

What you can see are two tanks of an eventual four tank propellant system.

On the outside, in several locations, we've got seven smaller thrusters

and we have a main engine, a liquid apogee engine,

which is fitted inside the cone.

The service module carries four fuel tanks,

all placed around the central core.

Each fuel tank can withstand an internal pressure equal

to being over 200 metres underwater.

The fuel is used for the satellite's engines.

The main engine fires the satellite out into orbit after it's launched

and then, for the rest of its lifespan, the other seven pairs

of smaller thrusters will keep the satellite in its orbit.

The fuel for all of these engines is delivered

by one of the most explosive mixtures known to man -

Nitrogen Tetroxide and Monomethyl Hydrozene, or NTO and MMH.

As you can guess from the names, these aren't particularly

pleasant liquids, so extremely toxic and extremely hazardous.

If you take in any of the NTO or the MMH,

basically you will suffer from burns, internal burning

and then eventually it leads to death. They are lethal.

The reason for choosing these dangerous fuels is simple -

their explosive quality.

The more explosive the mixture, the bigger the thrust,

and the less fuel you need.

But at three tonnes, this volatile mixture is still half the satellite's launch weight.

And with such an explosive power, the tanks need to be tested to destruction

to ensure they'll survive the trip into space.

Part of the testing of the propellant tanks

is to take it to an actual burst pressure.

We don't test it with gas, we tend to test it with water.

We increase the pressure and we get up towards 49 bar

and the tank will split.

Although the tanks won't be filled with fuel

until just before the launch, it's still delicate work fitting them.

We're just about to install the third propellant tank

into the structure.

Two are already installed, this is the third one.

It is quite tricky, yeah. And it's worth a lot of money,

of course, as well. About the price of a good house, actually, yeah.

The propellant tanks are built from titanium

because the metal doesn't react with the fuel in any way.

And they are machined to be wafer thin.

'We've got to be so careful that no damage occurs

'during this process, so it's quite delicate.

'It never goes wrong. It can't. It can't go wrong.'

LAUGHS

'Yeah, it's quite a big operation in the tasks that we perform'

so it's good to get it out of the way.

We've got it off to a T now.

Hopefully, tomorrow we'll be putting the other tank in.

It's the end of a successful day, and so, with the tanks fitted,

the next stage of the build will be adding the engines.

So when I tell people I work in the space industry,

it either sparks conversation and genuine interest

or is a complete conversation killer.

The concept of satellites came from Arthur C Clarke back in 1945.

He thought, "How can we transmit data from one side of the Earth

"to the other side of the Earth?"

These things will make possible a world in which

we can be in instant contact with each other, wherever we may be.

'Men will no longer commute, they will communicate.'

With the launch of Telstar in 1962, transmitting sound and vision

across continents and oceans became a reality.

'We have acquired the Telstar, Captain Booth puts his thumb up.

'And there is the picture direct from Telstar.

'This is the sort of image

'and the sort of sound on which, in fact, the future

'of inter-continental telecommunications

'via space vehicles is built.'

If you threw something at the horizon

it would just fall and drop.

If you threw it hard enough, you could probably throw it

past the horizon, and where would it drop to?

Well, it would continuously drop.

And that's what we're talking about. When you have enough energy

to throw a rock or whatever it is to the horizon

but you throw it hard enough that it then continuously falls,

then you're in orbit.

For a satellite to stay in the same place in the sky

it has to travel at the same rate as the Earth spins -

once every 24 hours.

This is called geostationary orbit

and it can only be achieved at 35,786km above the equator.

Any closer to the Earth and the satellite orbits too fast.

Any further away and it's too slow.

And that's why, in the UK,

all TV dishes point at 29 degrees above the horizon.

They are all receiving a signal from one particular satellite

that never moves in relation to our homes.

Microwaves won't work round the curvature of the Earth.

You need to be able to see the point

that you're transmitting to or receiving from.

The satellite receives and transmits signals through large antenna dishes

that fold out from its main body.

But they're very different from the dishes we see outside our homes.

They have carbon fibre skins bonded onto a Kevlar honeycomb core,

but there's another, more important difference -

they don't have a smooth surface.

The customers will specify a coverage. That coverage will be

to maximise access to the population and the service area.

So for the one we're looking at here,

which is over Europe, we're looking at the landmass of Europe,

so the more we can do to suppress the unwanted power over the sea,

the more we can put it where they're going to get their revenue from.

What we see in the top-right corner is what we're actually doing to the reflector.

We're slowly manipulating the reflector surface, very subtly -

in tens of millimetres - to actually produce a highly-concentrated area over Europe.

Shaping the reflectors in this way focuses the signal better,

and this is critical,

because the power they transmit back to Earth is astonishingly small.

The power that we're transmitting for each channel

is equivalent to a 100-watt light bulb, and that 100-watt light bulb

is 22,000 miles away from the surface of the Earth.

This is quite amazing technology, really.

The satellite is kept in its correct orbit

with a series of different-sized engines,

but given it weighs around six tonnes, it doesn't need the engines you may think.

If you were to fit this engine to your car, you'd have trouble

fitting in the three tonnes of propellant,

but you may move it very, very slowly. It's not going to take off.

But we're in space,

so we can use this engine on a six-tonne satellite and move it

through space because there's no friction, so it's relatively easy to do.

Once in geostationary orbit, the smaller thrusters will take over

from the main engine to keep the satellite in position.

We have thrusters dotted around so that we can control

the attitude of the satellite, to keep the antennas pointed, to keep the data flowing.

We've got influences from the Earth, which is not a perfect sphere,

so gravity will have an effect, and solar radiation from the sun.

We have large solar arrays that will pick up from the solar radiation

and slowly change the attitude of the satellite

and we need to fire a thruster to bring it back.

These manoeuvres happen regularly,

just to keep the satellite in its correct position.

But at the end of its life, these small thrusters will use

the last of the fuel to blast it even further away from the Earth

and into a graveyard orbit, which will be its final resting place.

Whilst all the structural components for the satellite are built in Stevenage,

the communications module is built in the company's other UK site at Portsmouth.

Portsmouth's history is well-known,

of course, for the maritime aspects of Portsmouth, but actually,

for a long time, maybe associated with that

there's been a capability

in defence electronics.

More than 50 years this site has been here, and over the last 20 years

we've seen this shift from defence electronics to space.

It's here that the electronic components

that form the communications module are made and fitted.

I don't think we talk about the space activities very much here.

I don't know whether it was because it started off

being defence-oriented and therefore quite secret,

and whether that's sort of part of the culture.

But nevertheless, people in this area don't normally associate it -

even the ones that live here - don't know that we make sophisticated satellites.

Over 12 months, thousands of individual electronic components

will be designed, built and fitted to the structure.

And their reliability is critical.

Failure in space is not an option.

Customers spend 150 million buying a satellite and if something

goes wrong they are not happy and they don't come back to you again.

This communication module is also known as the "payload".

On a spacecraft there are many parts,

but essentially it comes down to the payload -

the reason for it being there,

what it wishes to receive and what it wishes to transmit.

Each satellite is guaranteed by the company

to work for at least 15 years.

If it doesn't, they don't get paid, so attention to detail is critical.

The main driver for what we do here is reliability,

so on the site here we have 3,000 engineers - no service engineers.

Once the equipment on the spacecraft goes into service it has to operate

for 15 years without any reduction in its quality of service.

During that time, it gets hot and cold

so the heat on board the spacecraft makes the electronics grow old.

The radiation gives it sunburn,

so it has to survive through all those things.

At the heart of the communications module

are micro-electronic circuits called "hybrids".

These are computer processors, like silicon chips,

but are built for space.

The circuits are printed onto gallium arsenide,

a semiconductor, and bonded onto a ceramic tile.

Then they're connected with gold wire.

I'm placing a one-thou gold wire onto a substrate

using a combination of heat, pressure and vibration.

Each satellite is made up of around 20kg of pure gold.

It's 99.9% pure gold,

so, yeah, it's good stuff!

Only the best!

Pure gold is stable, doesn't degrade

and is an excellent conductor of both heat and electricity.

I was only 18 when I first did wire bonding

so I suppose I was quite adaptable to it.

Even though I've got chubby fingers, I like doing delicate work.

I haven't tried embroidery yet, though!

Once complete, the chips are incorporated into bigger electronic units.

I've been working on this for the best part of four years,

to actually get it from the early design,

right through to actually realising some of the hardware.

Decoding commands -

it's a bit like you sort of pick up your telephone and dial a number.

This particular unit, crudely, it's doing the same sort of function.

Then the components are tested again and again and again.

We've got about 8,000 test steps on this particular unit on its own,

so end to end, it's probably something like around two to three months, I would think.

But certainly on the design side, you know, you're very conscious

that this, actually, is going to be up there for 15 years.

That's quite at the fore of your mind in terms of everything you do.

It certainly is in my mind, anyway!

But not all the components inside the satellite rely on modern technology.

I've worked in this building for about 12 years,

but I've been engaged on crystal growth for the last 42 years.

-Morning, Mike.

-Morning.

-A huge problem for satellite communication is interference.

This happens when the outgoing signal is confused with the incoming signal.

This problem can be prevented by quartz crystals

built into devices called "resonators".

You can look on the quartz resonator as the beating heart.

If the heart stops, the patient dies,

and similarly, with a satellite,

if the quartz crystal stops oscillating, the satellite will die.

Oscillating crystals are used to control all the frequencies the satellite transmits.

And the quality of the crystal is critical

because if there's any impurity, they won't work.

This is a block of natural quartz that we purchased from a small company

that uses quartz for crystal balls.

Something like that would set you back somewhere between £10,000-£20,000.

-OK, Mike, bring in the crane.

-Because Derek needs to ensure the crystal quality and supply,

he originally used purchased crystals

to provide seeds from which he grows his own.

What we're trying to do here is to replicate the way

natural quartz grows in nature.

Natural quartz will grow deep in the Earth's crust. The difference

is we're trying to speed up the process so we can complete

the growth in, essentially, a few months rather than a few thousand years.

Over the next three months, under a high temperature

and enormous pressure, crystals slowly form in a solution of caustic soda.

We've been producing them for 25 years or so,

and so far nobody has beaten them.

Once they're formed, the pure crystals are first sliced...

..then shaped...

..and finally polished

until they are little bigger than a contact lens

before being incorporated into the satellite's electronics.

Our crystals are the purest in the world.

I can say that with absolute certainty.

Once all the electronic sections have been made,

they need to undergo a series of tests before being attached

to the communications module.

My name's Gary Stancombe. I've worked in vibration tests

and mechanical tests at Astrium for 15 years now.

I'm going to do some taping down to tidy it up and then we'll be ready.

OK.

This test is to check they will survive the extreme physical impact of the satellite's launch.

What we're doing today is we're going to subject this unit

to a sequence of vibration tests to simulate the launch environment

when the rocket lifts off and those eight minutes which will take it into space.

It does get a fair old shake. Today, we're going to subject it to a 20G vibration test -

20 times gravity. So anything in there will feel 20 times heavier.

Every electronic component is tested in this way,

sometimes to breaking point.

It is a hard test, yeah. It's a thorough test.

It has to be. We have to ensure that everything

is going to still be working once the unit gets into space.

We do see failures, but not too often.

But it's not just the vibration of the launch that each component has to cope with.

There are also massive shock waves.

These happen as explosive charges decouple each stage of the rocket.

From the solid boosters, the satellite housing

and main engine, through to the deployment of the satellite itself.

These are quite substantial shock waves so they need to be tested.

OK, and that's the shock test!

Once the electronics have survived all these tests

they can be fitted into the communications module.

Ian Kilby started work as a technician over a decade ago,

but he's now in charge of ensuring everything is connected correctly.

When I moved up from technician to engineer, at that point

you're no longer allowed to fit any equipment to the payload.

I do miss the hands-on side of things.

I used to enjoy the challenges that wave-guide

and co-ax present to the fitters,

and yeah,

sometimes I do wish, on particularly bad days, I wish I was back down there

on the tools and could not worry so much about things.

At the moment, the communications module is in two pieces

and Ian has a brave attempt at explaining how it all fits together.

Basically the signal, when it's received from Earth -

when the whole satellite's coupled -

there'll be an antenna, a receiver antenna on the top floor.

The signal will come in. It goes through the equipment on the top floor.

They amplify it, clean up the signal,

get the part of the signal we require.

It then travels down, down through the payload and there will be

some equipment called MPMs which are not installed yet.

It travels up through the switch network, goes up through the OMUX,

it's amplified again and harmonised a little bit more, the signal is cleaned

a little bit more again at the OMUX level, and then basically, it comes back

to the top floor, to a feed-horn, to the reflector and then back to Earth.

Ian's idiots' guide to a payload!

Modern telecom satellites can now transmit over 300 digital channels simultaneously.

But just 20 years ago, they could only cope with ten analogue TV channels.

And their speed of transmission, or lack of it,

was apparent to everyone.

THEME MUSIC

If you think back to Terry Wogan's show, when he used to have one on BBC One...

..the very first sort of satellite links, London to New York,

it was almost painful to watch.

She called me, did she?

# I hear you calling me. #

-Am I speaking to Linda Gray?

-HIS WORDS ECHO:

-..Linda Gray.

-Yes.

-Well, that's established that it's not working.

SHE LAUGHS

With the amount of lag, you had to wait for the signal to go,

or Terry's voice to reach the USA, and then the response time back.

It was an eternity. I'm sure people remember that.

It just took forever.

When we talk on satellite like this, you know, the miracle of sound,

there's just a little second or two delay.

So it's not that Barry's hearing has gone.

It's merely it's a long way to Los Angeles.

But now with the speed, the processing power and the speed

of modern satellites, it's barely noticeable. It's, like I say, within a second.

Once all the electronic equipment is fixed, the side panels

and the central structure are joined together to form the complete communications module.

These are some of the most delicate parts of the satellite.

And to safeguard them in the extreme environment of deep space, they need special protection.

My name's Katy Smith.

I'm the thermal architect here

and I've been working here for about six years.

My job is the thermal design, the build, the test of the spacecraft.

Deep-space environment's incredibly hostile.

It's incredibly cold - minus-270 degrees C -

whereas the sun-pointing surface could be in the region of 150, if not more.

And on top of that, you're in a vacuum so there's no convective environment,

you can't reject heat like you would.

For example, your cup of tea, when you blow on it, it removes the heat. It doesn't exist.

And the satellite needs to be able to operate within these massive temperature differences.

If we sent a spacecraft up into space with no insulation,

it wouldn't work.

You'd have one side with severe damage to the structure because of the sun's influence.

You'd have panels dropping off. So the distortions caused by the temperature differences

would buckle the structure and destroy it.

And the heat isn't just a problem on the outside of the satellite

because these extremes of temperature could be

disastrous for all the on-board electronics inside.

They can only operate between a cold minus-10 degrees

to a warm 40 degrees.

So to keep the internal temperature within this range,

-the satellite is wrapped in material called Kapton.

-Kapton is a high-temperature layer.

It's very robust. You can use it in an environment from minus-250 degrees C,

up to a continuous operating temperature of about 290 degrees C.

I think the best way of describing it as a home product would be a Quality Street wrapper.

It's difficult to tear, incredibly light,

so for a space environment, it's hugely applicable.

But Kapton can't protect the satellite on its own.

What you're actually seeing here is a very thin deposition of aluminium.

So here, when you can see the gold outer layer, it's not actually gold.

What you're seeing is the vacuum-deposited aluminium

behind the Kapton, like that, giving it an amber or gold effect.

The aluminium-backed Kapton forms a blanket, insulating the satellite

and preventing heat being lost to deep space, while at the same time

stopping the sun overheating the electronics inside.

I know it seems kind of counterintuitive

because you've got large amounts of energy coming in from the sun,

but to balance it out and find a happy medium,

you have to block some of the sun, dump some of the heat

and supply some heat internally. It's a really complicated juggling act.

The Kapton blanket is the first line of defence at keeping

the satellite at a reasonably constant temperature.

But the electronics inside also create their own heat,

and this, too, needs to be dissipated.

To do this, some very clever engineering

is also incorporated into the two large structural panels

on the outside of the service module.

A complex matrix of pipes act as massive radiators, dumping heat generated by the electronics

and keeping the internal temperature constant.

A heat pipe is a very, very effective method of moving heat from one local region to another.

There's no working parts, no electricity required,

so power-wise, it's good.

But unlike household radiators, these pipes contain ammonia,

because it boils and vaporises at just the right temperature -

33 degrees centigrade.

So what happens, is at one end,

in the hot, high power dissipation region,

what will be a liquid at that stage evaporates.

The vapour then travels up the tube, up the centre of the tube

to the cold region and at this region it condenses.

It dumps the heat and then travels back down

to start the whole cycle again in the form of a liquid.

There is one final line of defence,

which is also crucial in reflecting heat away from the satellite.

And it's all down to this team.

I know it sounds very cheesy,

but it's the satisfaction of knowing

that you're actually contributing to mankind.

You see that panel that comes in with no mirrors on it.

And then, when it goes out, it looks beautiful, all polished up.

And you know it's serving a purpose up there to protect the spacecraft.

You stand back and look at it and go, "Wow, we did that."

A thin silver surface of mirrors will reflect the sun's rays

away from the satellite and is its last form of heat defence.

These are 100 microns thick.

So they are very thin, it's about as thick as a human hair.

We have sheets of 198 mirrors at a time, so they're very fragile.

The glass the mirrors are made of also helps to emit heat

away from its core.

Just want to feather that in.

Well, we've put the activator in and we've only got 30 minutes

to apply the adhesive, put the mirrors on and get it under vacuum,

So, it is a bit of a rush.

It's eight hours of prep for 30 minutes of organised chaos!

The surface that you can see is 99% silver,

it's pure silver.

And the back surface, the darker side, is nickel and chrome,

which is called nichrome

and that is there purely to stop the silver from oxidising.

I you remember, if you can think back

to your grandmother's silver dinner service when it goes black.

These will go black and they then, they don't become reflective.

That's it. We're done.

In Portsmouth, Ian Kilby is putting the communications module

through its final checks

in a special room called an anechoic chamber.

We're firing some microwaves at the payload

to see if there are any leaks in any of our co-axial connections.

So, if you imagine the same signal is inside the payload,

it's leaked around and it's coming out of a hole,

it could, in turn, effect the input into the satellite

and the output going out.

So, it could blind itself, in effect,

with its own loop of RF signal.

It's been quite catastrophic in the past to have EMC leaks

because it actually interferes with the transmission

that's coming from the comms module back to Earth.

The chamber is designed to block out any radio signals

from getting in or out.

It's almost like taking a telephone towards a radio

when you're phoning the radio station.

You get that a big screaming squeal, in an effect not a screaming squeal,

but obviously it has a similar effect on a telecoms payload.

With the final testing complete,

it's time to box up the communications module

ready for shipping.

It's always a nerve-wracking moment to pick up something of this value.

It's all the fruits of our labours over the last few months.

Lots of things potentially could go wrong.

You know, we're picking it up with a crane.

Failure with the crane or something catastrophic could happen.

Even when it's turning into the box, it's quite a nerve wracking moment,

it's quite a large mass.

After over two years of intense and complicated engineering,

most of the work that takes place in the UK is done

and the modules are shipped to Toulouse in the south of France.

It's always quite pleasing when you see another delivery going out of the door.

It's in this facility where the final assembly happens.

It's a complicated and delicate process.

First, the service module made in Stevenage

and the communications module from Portsmouth will be joined together.

Then, the solar arrays are added.

Finally, the antenna will be attached.

Graham Viney has escorted the service module to Toulouse

but luckily for him it's his French colleague,

Pascal Gaudin, who's in charge.

This phase is key for Pascal,

he's responsible for the integration here.

For me, you can probably tell I'm a little more relaxed,

but I understand what Pascal is going through, but it's not me.

Here, at that point,

we have a few millimetres, really, tolerance, that's all.

We are all feeling a bit nervous about this

because we have to look at all the proximities

between the two structures

and spacecraft is never the same, so each time there are surprises,

so, we have to be very careful about this operation.

After six hours careful work, the two British built modules are successfully coupled

and the main body of the satellite is complete.

I think more relaxed,

we passed the most critical phase of this operation.

Now we still have to fit all together the different interfaces,

which are on different levels

but so far it's a success,

yes, this coupling is a success.

Completing the satellite in Toulouse will take another seven months

of dedicated work.

Although all satellites carry fuel for the engines

they are actually solar powered.

My name is Ludwig Grandl,

I am the manager for the Centre Of Competence of Astrium Solar Arrays,

here in Germany.

For the last 40 years, the main centre for solar array production

in Europe has been this factory.

The satellite will have over 20,000 individual solar cells,

each helping to generate the electricity needed

to power the electronic systems.

What you can see here, that's a typical solar array

for our Euro star programmes.

One wing as we see it here completed with the mechanism

is around 130kg.

Though, on a satellite we have two of them.

Each array is 20 metres long and yet their combined total weight

is the equivalent of just three average sized men.

The arrays are folded

against the satellite's structure for the launch,

but once in space, they gently unfold,

using a system of springs and wires.

Let me say, we are extreme reliable in this way

and we never lost function of one of our solar arrays

for whatever reasons.

The solar arrays are dependent on a drive mechanism.

This allows them to move and always face the sun

and this machine has been designed and built back in the UK

by Bob and his team.

This is one of the key critical elements in the spacecraft,

so it has to operate every day for 15 years.

If we lose this, we lose power into the spacecraft,

that causes the mission failure.

This mechanism is one of the most critical components

of the whole satellite.

It has to move the solar arrays to face the sun every second

of every day for its entire 15 year lifetime.

Because if it doesn't, the satellite will loose power.

This provides two functions.

It provides the power transfer from the arrays

and then it also enables the arrays to track the sun

by rotating at one cycle per day.

This is the spacecraft. These are the arrays.

So, they sit in here holding the arrays

and if you imagine my fist as the Earth

and the camera perhaps as the sun,

then as the Earth rotates and the spacecraft rotates,

you'll see that if you don't rotate the array to track the sun,

then you don't get the power.

So we have to rotate, as this space craft sits

in geostationary orbit above the equator, moving round the Earth,

we have to rotate these so they are always facing the sun.

There is a very, very high pleasure in engineering

in getting something right.

The fact that you can see something which was,

in effect, something in somebody's imagination turn into reality

and for it then to be successful, is a tremendous kick, it really is.

With everything fitted and tested the satellite is carefully packed

into a hi-tech crate and sent by plane to the launch site...

..Where it's prepared for its final journey.

It's a tense time for the whole team.

We're in the satellite control centre and this control centre

takes over control of the satellite

after it's separated from the launcher.

It is critical, it is a crucial phase.

Good line pressure to fire the thrusters.

At the moment, this team here is running through a rehearsal.

There is a computer simulating everything the satellite does,

we can send commands as we would and it responds like a satellite,

and it's really testing, testing the team.

As the satellite is being prepared for launch

on the other side of the world, these rehearsals are critical

because when it leaves the rocket that gets it into space

its orbit will be elliptical.

The moments leading up to the firing of that main engine is very tense,

a lot of pressure,

and if it doesn't happen we have a lot of people looking at us.

Graham and his team will then have to fly it into the correct geostationary orbit

by remotely operating its main engine and thrusters.

Each burn will take up to 90 minutes, but overall

the procedure will take two weeks and use half of the available fuel.

Every time we circularise the orbit of a satellite, there's something

about those two weeks where something will challenge us.

The launch day is fast approaching.

And over 4,000 miles from Stevenage,

Bob Graham is following the satellite's journey.

We're in French Guiana, which is in South America

and very close to the equator.

Green, lots of green trees.

Very, very hot, about 37 degrees today.

One of the reasons we launch from the equator, or very close to the equator,

is because the earth spins

and there's a faster rotational speed actually on the equator.

It makes business sense to fire a rocket into space from the equator

as it's cheaper to launch.

Which means less fuel, means a lower cost launch

and from the spacecraft's perspective

it's actually being placed closer to its end orbital position

so, again, it uses less fuel on the spacecraft.

The satellite will be lifted into orbit by an Ariane 5 rocket.

At over 50 metres and almost 800 tonnes fully fuelled,

this is the workhorse of European space exploration.

Our satellite is right at the top of the launch vehicle

you can see the fairing at the top the curved part

is literally sitting right inside there.

Watching the launch has a special resonance for Bob.

I've worked in the space industry for nearly 30 years,

never seen a launch in my whole career, never.

To be so close is a really incredible and moving moment

because a lot of people do not actually get to witness this.

I feel terribly privileged that I'm here

and I would see myself as a representative of the people

who've actually contributed to the delivery and the success of this spacecraft.

You're talking about 30 million horsepower at launch.

So, the thrust when this vehicle takes off

is about the equivalent of 12 A380 airbuses taking off.

This is a pretty rough ride for the satellite

and that's what all the design and everything is about.

We have to make sure it survives this phase

and then it can go into operation.

So, it's, er, yes,

this is the bit where we all get that...little bit of butterflies in the stomach,

which is saying, "I hope this goes all right."

Maybe even some sweaty palms, let's wait and see.

Later that day,

the rocket is carefully rolled out to the launch pad.

It's taken over two years, in excess of £100 million

and some exceptional engineering to get this far.

And now, there's nothing Bob can do.

Except wait.

Launch day.

And on schedule, the automatic countdown commences.

At first, everything goes smoothly.

But at just 1 minute and 47 seconds before ignition,

the countdown stops.

The window has opened and there's a hold.

There's some problem somewhere which they're checking.

They'll restart the seven-minute countdown.

So we will see how it goes from here.

Little butterflies. Is it going to go? Is it going to go?

And is it going to be...

..as they say it is in terms of the light, the noise

and, er...yeah.

So let's see.

As night falls, it's apparent that the technical issues

are more serious than first thought.

And after an hour of waiting, the launch is cancelled.

The next morning, an initial investigation suggests

a faulty fuel valve in the rocket caused the postponement.

Here we are in Mission Control Jupiter, the morning after.

This is the place where that final decision was made last night

to postpone it.

As an engineer, I know this is the right decision.

The decision made last night was the right one. But...

..as a man, as a person, as a representative of a team,

yes, there's an element of disappointment that it didn't happen.

Space is difficult. It is about risk.

It is about showing that our products are good,

but we can't afford to take the risks. But it will happen again.

Maybe I won't see it, but others will and I guess that's life.

And finally, the satellite was successfully launched.

Today, 35,786 kilometres above us,

the brand-new communications satellite

is now being prepared to broadcast pictures directly into your home.

So keep watching the skies.

From sketch to structure, see how designs come to life by visiting:

And follow the links to the Open University.

Subtitles by Red Bee Media Ltd

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