Destination Titan

January 14, 2005, the day had finally arrived -

the day that I'd thought about every day for 17 years.

1.5 billion miles away, out there near Saturn, there was something

that we'd built and it was hurtling through space at 20,000 mph.

Would it do just what we'd designed it to do or would it all be wasted?

We went into the science room that morning

knowing that whatever was going to happen

was going to happen, and this was the day.

There was an enormous air of expectation.

Basically anyone I met

was as excited but also as nervous as I was about the whole mission.

Frankly I think we were all petrified.

But the very worst thing that shouldn't have happened happened.

And it turned out it was a major problem.

I just wanted to go away and cry in a corner.

That really ramped up the nerves and there's a missing command, what else is wrong?

I really had visions now of the last 17 years having been wasted.

# MUSIC: "Red Planet Rock" by Don Lang & His Frantic Five

# Everybody, watch the sky

# The weather's all jumping and I'll tell you why... #

Growing up in the late 50s, all I knew about space travel was

probably from reading about Dan Dare,

for example, in the Eagle comic.

I knew very little about the planets, probably from schoolbooks.

All we knew was from often rather blurry, indistinct images from telescopes on the ground.

I think I knew that Saturn was a large ball of gas.

We call it a gas giant, and it was about 1 billion miles away from us

here on the Earth, but I certainly didn't know anything about Titan.

I didn't know that it was one of Saturn's moons orbiting around it.

I mean you have to remember we didn't have any spacecraft images of course,

and then something happened to change all of that.

-NEWSREADER:

-'Half an hour ago, the Russians announced

'that they had put the first man into space.

'It's the voice in space of Major Yuri Gagarin.'

'It must be one of the greatest scientific

'events for one of the greatest occasions in the history of man.'

It was absolutely mind-boggling.

It's impossible now really to

imagine the impact that it made.

Man in space.

-Excuse me, what do you think of the news?

-I think it's fantastic.

-Well, I can tell you he's now back, safe and sound.

-Really?

I didn't think he would get back.

Well, I say, very best of British good luck to the chap myself.

Within months of Gagarin's flight, he embarked on a world tour

and I think it's true that the first port of call was the United Kingdom and London.

Major Gagarin, could you tell us what you think of the reception of the British public?

TRANSLATOR SPEAKS RUSSIAN

GAGARIN SPEAKS RUSSIAN

The welcome I have been given by the British public has been overwhelming.

It has been most friendly and kind.

TRANSLATOR CONTINUES: 'I see smiling faces everywhere...'

What about you, would you like to be a spaceman?

Oh, well, it all depends.

If it comes up, like everybody in a kind of craze,

I think I might have a go.

-You might have a go, might you?

-Yes.

-What did you think of the Major?

I liked his uniform and I like the company all around us.

The school that I was at, Highgate, was very close to Highgate Cemetery.

Of course, every visiting Russian dignitary had to visit the tomb of Karl Marx.

I remember school was cancelled for the afternoon.

It was such a big event, you know, Gagarin coming to London, coming to Highgate.

I think I only decided to come along here at the last minute.

I'm not sure why. I don't know if I'm a believer in fate but it must have been fate, mustn't it?

And it was my eureka moment - seeing that man standing here -

asmall man, but the thought he had been in space for what was it, 96 minutes?

The first astronaut, and I was hooked from that moment on.

The Gagarin flight was really what kickstarted it all.

It really took us out of that science fiction era

into the era of practicality,

and one can see it as the first step on our exploration

of the solar system with humans and also with robotic spacecraft.

It's one of those things, if you grew up in the late 60s, early 70s,

you know, space was everywhere.

It was the most exciting thing, you just wanted to be involved in it,

probably couldn't even imagine that you would be.

There was a little bit of affluence

and some of the social boundaries and barriers were breaking down.

There was the so-called Youth Revolution and I was caught up

in many of the demonstrations that were going on against the Vietnam War.

It was a fascinating time.

-NEIL ARMSTRONG:

-That's one small step for man,

one giant leap for mankind.

I was always interested in space.

I was interested in unmanned space exploration,

seeing other planets up close.

All of this helped us cement, I think, this hope,

this dream that I had that I could actually take this further.

I could get my physics degree.

I could then perhaps do a PhD,

and really move to be a part of this whole worldwide space activity.

I stir it up with my feet.

There it is, I can see it from here. It's orange.

-AMERICAN NEWSREEL:

-Only once every 175 years are the major planets -

Jupiter, Saturn, Uranus, and Neptune -

so aligned that a spacecraft can visit all four on a single flight.

The rare opportunity to probe these planets occurs in this decade,

the 1970s, and will not recur until the middle of the 22nd century.

Most of what we knew about Titan, at least at this time,

was from the Voyager spacecraft.

We knew that Titan was about 5,000 km in diameter, so bigger than the planet Mercury.

It had a thick atmosphere.

This is what really made it stand out

amongst all of the planetary satellites in the solar system.

It's the only one that does.

But we knew essentially nothing about the surface

because Titan is permanently shrouded in orange haze or smog,

which meant that none of the images showed anything of the surface.

We know it's very cold.

Saturn and its satellites are so far from the sun.

The atmosphere is very complex,

it was known to have at least 12 different gases and probably having

some similarity to Earth's very primitive atmosphere,

one that we lost probably billions of years ago.

There was organic chemistry on Titan which was interesting but that Titan wasn't warm enough

to have a liquid water which of course is one of the prerequisites for life as we know it.

And I think Titan sort of faded into the background in a sense

for much of the following decade.

Well, towards the end of the 1970s,

jobs in British universities were very difficult to come by

and I saw an advertisement,

which was very hard to resist, to go and work on a project called Giotto.

Now Giotto was Europe's Halley's Comet mission and the job was at the

University of Kent to be project manager for the dust instrument.

I applied and I got it so, at the end of 1981, we moved to Canterbury

on a two-year contract and I ended up staying there 18 years.

Giotto flew 594 km from the nucleus of Halley's Comet.

I mean, it was remarkably close.

And we detected about 30,000 dust particles.

These are the particles that make up the tail of a comet.

I think it was a mission that gave Europe confidence that it could really do ambitious things in space.

After the success of Giotto, the European Space Agency

were very democratic about selecting the next scientific mission.

They had five candidate missions

and we got involved in a team on a mission called Vesta.

Now Vesta was going to fly past an asteroid

and we were part of the group that was looking at the possibility of firing some penetrators.

They would be fired into the surface of the asteroid and make measurements of the physical properties,

and we came to the day of selection and, to our horror, it wasn't Vesta that they chose.

They selected a mission called Cassini, going to a place called Titan -

a place that I'd hardly heard of and we were completely deflated and ejected by this.

I remember still the journey back to Canterbury from Bruges.

We went on the train and the ferry, and it was a pretty depressing, glum journey.

We got back to the lab and I said,

"Look, have we really wasted the last year?

"Is it possible that some of the work that we've done on the Vesta mission,

"which they didn't choose, we could actually adapt

"to this strange place Titan that they were proposing to go to?"

We sat down with a cup of coffee and had a look at what it was that the European Space Agency had chosen.

Cassini, as proposed, was going to be the most ambitious space mission ever sent to the outer solar system.

It was planned to carry the first dedicated set of instruments for Saturn and its system,

and it was to carry a probe that would detach and land on the surface of Titan.

Now, pretty soon, we realised that the part of it that really interested

us was the probe, which was going to descend through Titan's atmosphere.

It was going to make the bulk of its measurements during the descent.

And we realised how embarrassing it would be if the thing landed

and it didn't have anything with which to make measurements on the surface.

So we literally listed all of the physical properties

that you might want to measure on the surface of Titan.

We then wrote a proposal in response to the call for proposals to produce

a quite ambitious, though small, little instrument called the Surface Science Package.

We beat the deadline by about a day.

We sat and waited for the decision.

And, to our amazement, we were selected.

A new and very exciting space probe is being planned for the 1990s.

Dr John Zarnecki is closely associated with this probe,

and we are delighted to welcome him now to the Sky at Night

for the first time but I certainly hope not the last.

-Welcome, John.

-Thank you.

I do my Sky at Night programme.

I did do a programme about Titan, who to invite on it?

Obviously, John. I didn't know then what a good broadcaster he was,

and he came and we discussed Titan.

'But, of course, so far,'

we've only been able to study the top part of it.

We still don't know what the surface is like and that's the reason for sending up this Titan lander.

Will you tell us about that, John?

I should tell you that it's already been christened in fact.

It's called the Huygens probe, named after the Dutch physicist,

Christiaan Huygens, who discovered Titan.

'I was billed as a Titan expert.'

I hadn't written a single scientific paper about Titan and this was a very bizarre situation.

He didn't know much about the surface of Titan, but neither did anybody else, me as much as anybody.

All in all, this is one of the most ambitious vehicles ever planned,

what do you think are the chances of success?

We must be optimistic, you would never embark on a mission like this if one wasn't optimistic.

And I expect that we might be sitting here in 13 years' time discussing the results from the Cassini mission.

'I think it began to dawn on us, just in the weeks after we were selected.

'We had to produce an instrument, one of a set of six

'scientific instruments, a bit bigger than a shoebox.

'It had to travel in a probe in deep space for over seven years,

'descend through this thick, rather mysterious atmosphere

'and then make measurements on this very alien and unknown surface.

'And it had to give us answers, it had to make sense of this alien world.'

I mean that was a daunting prospect.

I had to start building up the team.

There were several critical positions.

Arguably the most important position is the project manager.

That's the person who really runs the show day to day and brings the whole thing together.

'OK, one thing we've got to decide is exactly who to send to the meeting with Peter.'

One of my colleagues knew John Zarnecki from maybe 10, 15 years earlier

and they said, "I saw John the other day and he's looking for a project manager,

"why don't you give him a ring?"

And, amazingly, because of him, I had this new space science career.

The instrument had originally been selected in 1990 but the team were just getting going in 1992.

When I arrived they'd just really had a few prototypes on the bench, some of them were very Blue Peter.

I remember a washing-up bottle with a steel ruler attached that was the

density sensor and the thing was huge and we had to turn this into an 8g sensor to fly to Titan.

When Mark came on board, there were two big issues that we had to face.

One was to put the final team together and, more importantly, was to get the funding.

Because being selected was only half of the battle.

We then had to get funding from our national agencies.

'Our funding situation is stable,'

if you call underfunding a good thing to report.

We were underfunded two years ago and we're underfunded to the same extent now.

We were cut back to about two-thirds of what we actually needed to do the job,

so we had to look at clever ways of getting round the funding shortfall.

This was around the time of perestroika, when the Iron Curtain was coming down.

-NEWSREADER:

-Bulldozers tonight began to open new holes in the Berlin Wall.

Throughout the day, thousands of people have been crossing freely

from East to West Berlin and back again.

I saw an opportunity here to use some of the professional connections that I had with Poland

to see whether we could go there and use their desire to work with the West in scientific research,

and we found out that they were quite experienced at building space instruments,

so basically we cut a deal.

They would build a part of the instrument

in exchange for coming on board and seeing essentially how space research was done in Western Europe.

Now that was one thing that we did, the other was to take advantage

of the fact that we were a university

and one thing that universities have generally in profusion is students,

and, generally, students are fairly cheap.

I won't quite say slave labour but nearly.

MUSIC: "Mirrorball" by Elbow

The whole project seemed a lot like science fiction in the sense that somehow we were going to

build this thing that was going to travel a billion miles through space

and then parachute down through this atmosphere at minus 200 Celsius

and touch the surface of one of the moons of Saturn.

It just boggles the mind that you can contemplate doing that.

Ralph is enthusiastic about everything he turns his attention to,

and he became very quickly embroiled in all aspects of Titan.

And one of the tasks that we assigned to him was to develop the penetrometer.

One the things we really want to answer with the Surface Science

Package is what is the actual nature of the surface of Titan?

What's it made of? Is it solid like ice or is it slushy or is it liquid?

This part of the package, called a penetrometer, aims to do that by measuring how hard we land in it.

As the probe comes down, we measure the impact forces.

It's very strange, you sort of come into this from the outside thinking

that there's some massive team of top notch engineers and scientists

who've done this all before and that you will be allocated some little part of it.

And the reality is, there's never enough people

and everyone is improvising because nobody's built anything that went to Titan before.

So it was at first a little strange and surprising that

I'd get to do this but it was an incredible opportunity.

In the early days of the project,

we were being followed by a BBC crew who were filming

some aspects of the project for an Open University programme.

It was an eye opener - the first time I'd been involved in that kind of thing.

They actually set up a little video diary for us,

a little passport photo, where you just sit in front of this video camera and say what had happened.

It's April 13th, last week we donned these crazy suits and went in

the clean room to assemble the engineering model penetrator.

This instrument will perform thermal properties measurements

to show the thermal conductivity and the temperature of the Titan ocean.

This will be sent to a way to be shaken, baked,

and electrically tested in what is called the top hat,

that is the thing that holds all the experiments.

As you can see, it's quite small and fiddly,

but I'm rather pleased with it.

Science students tend to be nerdy,

and, I think, as a group we conformed to that stereotype,

so that it means you're really utterly focused on what you're doing

when you have three years where you have no other commitments other than to do your research,

and because building a space experiment going to Titan is such a motivating thing,

it was really wonderful actually to have that focus.

The penetrometer was a fairly simple sensor in concept,

but actually doing it well took a lot of work and a lot of effort.

Ralph was involved with running a load of prototype tests and dropping things into bucket of sand

and seeing how different tip shapes responded, etc.

I remember one of the first things we did was got some sand from Whitstable Beach

and that was a huge mistake because it was real sand at the sea and so it was all wet and salty.

And, of course, salty water is an electrical conductor and of course

the signals we got from that were just terrible.

It was building an instrument to go somewhere that we didn't know what

we were going to land on, and that was a real part of the fascination.

It's one thing to make a measurement in a laboratory, it's another to make an experiment that is going

to work, for sure, seven years later after travelling through space for a billion miles,

that's going to work at 200 degrees below zero

and that isn't going to suffer any kind of problem.

The biggest fears we had were landing on absolutely sharp, exposed ice, which meant the runners of the

probe might die pretty quickly, and our challenge was to get the data back before the probe died.

At the time, one of the main speculations about Titan's surface

was that it was covered by a global ocean of liquid methane

and so I spent quite a lot of time doing my PhD

modelling the splashdown dynamics, looking at all the old

Apollo literature of how a capsule decelerates when it hits the water,

and trying to figure out how much the Huygens probe

would decelerate if it landed in liquid methane.

A lot of it was theoretical stuff.

Do we have global oceans, do we have seas, do we have lakes, anywhere in between?

The natural speculation was, Well, it'll be like landing

on Mars or landing on the moon but we had no idea what the materials really are, if it's ice

or if it's ground-up ice like sand, or if it's some sort of organic dust that's very fluffy.

So we had to consider all these possibilities.

We certainly didn't know anything

that would let us exclude any of them.

This is the final engineering model of the Huygens Surface

Science Package, containing its nine different sensors.

We've got here the speed of sound instrument

to measure the speed of sound in the atmosphere and on the surface.

Here we have the sonar, designed to send a signal down to the

surface of Titan or to the bottom of the lake to measure its depth.

Inside this enclosure here, we've got six further instruments to measure

various properties of the liquid or the solid surface,

and finally we have here the penetrometer.

MUSIC: "Future Proof" by Massive Attack

Yeah, output lines are clear and we're running at about 6 PSI over ambience.

Once you get into the hardware phase of the project,

there's testing, testing, testing,

and some of these tests run for tens of hours at a time.

There were times when I felt that I knew my milkman better than

my family because I was arriving home at 5 o'clock in the morning.

Can we have temperatures please, James?

Top cavity 111, bottom cavity 114.

For this particular mission, one of the really unusual things was when we got there, we were going into

a very, very cold environment, so many of the sensors we needed to test in liquid methane.

It is a little bit hazardous, so we were doing this on the roof of the physics building,

I guess the logic being that if we blew up, we only blew ourselves up and no-one else.

A project like this inevitably put strains

on all the individuals involved, and that's challenging enough.

I'm not sure that my family really understood quite what I was doing,

they sort of supported me, but probably thought that I was the crazy scientist

and maybe every family had to have one crazy scientist.

I was very lucky in the sense that I'm quite a self-motivated,

self-driven kind of guy so I didn't need a lot of handholding.

And that was just as well because John was a busy man.

The job he was doing as a university lecturer and building a space experiment was quite demanding,

and he was going through some personal difficulties at the time too.

The early days of the project coincided with the breakdown of my marriage,

so I have to say there was about a year in the project

that was very, very difficult.

I find it difficult even to think back to those times.

It was difficult to keep everything going, frankly,

and I was very lucky I had a really good team who, when things got very difficult for me,

they were more than able to keep the show on the road.

There were some very, very long working hours involved, particularly when you get to the flight model

and you're trying to get everything to meet the deadline.

If you miss the delivery, you're not going to Titan.

You ever have one of those weeks where nothing works?

Our fax machine is broken, the photocopier didn't work,

the coffee machine is broken down,

even the BBC's bloody light has stopped, so we have to improvise with this desk lamp.

I'm sitting in this dark old laboratory with an experiment that's not working and you sort of think,

is this really what I want to do? Have I made the right decision?

But then you remember the bigger picture.

The project developed, it was hard and painful at times, but finally we got to the very last test.

This was the vibration test.

And can you believe what happened?

The damned thing broke.

The structure which held our instrument together cracked.

I was personally devastated to hear the news.

I realised the impact of it straightaway,

that even just rebuilding the top hat was going to be a problem,

but the fact we had to rebuild the sensors too

meant that every aspect of the project had its hands full with a huge, huge workload.

It was really the possibility that the European Space Agency might say, "I'm sorry, guys,

"you're not going to make the delivery date,

"you're not going to be on the probe, you're not going to Titan."

And, at that point, it was at least four years of my life dedicated to that instrument.

We had to find a solution, we had to get out of this hole.

It had taken maybe six months to build this flight model,

and we were two weeks away from delivery and had to rebuild the whole thing.

For John, it was an even longer time on this project

and, again, he knew instantly that there was a chance

we were getting thrown off this mission.

We came up with a strategy, whereby we would deliver the engineering model to the spacecraft,

that would enable ESA to continue with their programme,

they couldn't hold it up.

This meant we had to dismantle the whole thing, remove all the harness,

fix the structure but also build flight spare instruments,

calibrate them, put the whole thing back together.

In the end, it took about three or four months to go through the whole thing again but it was touch and go.

We worked around it,

we came up with an alternative design, and we delivered that to the spacecraft.

Late, but it was working.

MUSIC: "Safe From Harm" by Massive Attack

-NEWS REPORTER:

-Titan, the hazy moon around Saturn.

Today a huge rocket is being prepared to explore that distant world.

Europe and America have joined forces in a 3.5 billion mission called Cassini.

This was it. We flew out to Florida for the launch.

To our surprise, we were actually greeted there by protesters.

'With legions of protesters climbing the gates at the air station,

'opponents have maintained that

'NASA's plutonium powered satellite could kill the innocent should something go wrong.'

They blow up all the time here, you know and,

for some reason of insanity I can't imagine,

they're going to stick 72lbs of plutonium atop this thing.

What I want to see is a safe world.

I don't want nuclear in space.

If you go out to the distance of Saturn from the sun,

sunlight is very weak,

so you can't use the traditional way of generating electricity

on a spacecraft, which is to use solar cells.

So, you have to do something else and this is true

of all outer solar system missions.

And what is done is to use radioactive material.

This case plutonium.

And you use the radiation that it emits

essentially to generate electricity.

That's the only way you can do it.

There seemed to be a sort of knee-jerk reaction that

radioactivity is this terrible thing but, for me, it was just

a necessary part of the spacecraft.

But how would the protests affect the launch?

Would they get in the way, would we be getting tomatoes thrown at us?

It took me back to my time as a student in the 1960s

when I was doing the protesting, when I was carrying the banners.

Now there I was, I was having to cross the picket line.

The launch was in the middle of the night at about three o'clock

in the morning and I think, because of security and so on,

they had special buses arranged for us.

Are you nervous?

Yes, I am.

Yeah, I'm a little nervous, yes, just a bit.

Seven years' work and this is the make or break night.

There's a lot of work down the line from here but this is really

one place where it could fall down.

'It was always in the back of our minds that any rocket is only'

95, 97% reliable, so there's a good chance

that if the mission fails it was going to fail now.

'Launch command systems now enabled.

'T minus 1 minute 30 seconds.'

Sat there biting fingernails and trying not to get too nervous,

waiting for the OK that they are going to launch.

'T minus 10,

'9, 8, 7...

'6, 5, 4,

'3, 2, 1.'

I saw flames at the base of the rocket and the first thing

that went through my mind was that the rocket's caught fire

and it's about to blow up or something because the

ignition happens but it's several miles away, and so the sound of the

ignition hasn't reached you yet,

you just see the flames and then you see the rocket start to ascend.

Then the direct sound hits you and there's this wall of deep

rumbling bass and you get a sense, wow, now we're really on our way.

Cassini goes up and it was almost by design, there was a cloud about,

I think, 1,000 feet or so right

above the launcher and then after a few seconds it went into this cloud.

There was almost an explosion of light, it looked like the thing had blown up.

This cloud was just a huge ball of fire, it looked like.

For a fraction of a second it was horror, it's gone, we've lost it,

but then we saw Cassini appearing above the cloud.

It was coming through and then it went up into this clear

black sky, absolutely serene, a truly wonderful sight.

Once it was off and through that cloud, you knew it was going,

you knew it was going to be a good launch.

I guess I kept an eye on the rocket all the way up

till it was a tiny dot.

During the journey to Titan,

we actually moved our team to the Open University in Milton Keynes.

A lot of things do happen in some respects, I mean one is rather sad

because the team that we'd built up to design, build, and launch the SSP,

much of that team dissolves.

We don't have the funding to keep that team going all the way through.

But we kept a core team together because roughly every six months

we switched the instruments on and we ran through

what are called housekeeping tests.

How do you go into mode 4, on time or on altitude?

This time we went in using the 7 km as altitude.

We'd check out the instrument,

make sure the spacecraft was working fine, that our instrument was working fine.

There were a few minor things we monitored

and a few software bits we changed. Nothing too major from our side.

What you have do understand is that when Huygens

was planned to be descending onto the surface of Titan,

it would be relaying its data not directly back to Earth,

there just wasn't the power for that,

but sending the data up to Cassini,

which would be flying some thousands of kilometres overhead.

Cassini would then relay it a few hours later back to the Earth.

There was a major scare on the spacecraft.

They tried a particular test of the communication system and realised that there was a

problem and with the mission as it was designed,

we weren't going to get the science data back.

One thing that was tried was using a radio telescope on the ground

to pretend to be Huygens and transmit a signal as if it was Huygens,

to check that Cassini could receive that signal correctly.

When the results of the test were reported to us in a science meeting,

they said we did the test and we're not sure quite what happened

because we didn't get all of the data back.

To put it simply, it's as if Huygens was transmitting on Radio 1

and Cassini was receiving on Radio 2.

In other words there was a very slight mismatch

in the frequencies but it was enough

to potentially scupper the whole of the Huygens project.

That was obviously a huge, huge problem,

very frightening from the scientists' point of view

but the system quickly got together and came up with some options for solutions.

There were 11 possible

options that were found that might be able to address this problem.

In the end we picked on one of them as being the potential saviour.

This involved Cassini, instead of releasing Huygens

on the first orbit around Saturn, releasing it on the third orbit.

That would change the geometry between Cassini and Huygens by just the right amount

to bring the two frequencies back into synchronism, quite remarkable.

'Now how long does it take a spacecraft to travel 2 billion miles

'between planet Earth and Saturn?

'Nearly seven years is the answer and tonight,

'for the spacecraft Cassini, the journey is nearly over.'

Well, today's the culmination of our seven-year trip through

space and we are arriving at Saturn and we're going to fire the engine to stop us into orbit around Saturn,

so it's the end of the trip but really the start of the tour.

The excitement for me is in the future when we get close to Titan

but this is a big moment so kind of a bit of a party atmosphere here in Pasadena to celebrate the arrival.

There have been one or two occasions in planetary exploration where spacecraft have blown up

on arrival when they've used their engines for the first time.

Current Cassini altitude 20,700 km,

12,900 miles, with a speed of 30.7 km per second, 68,600 mph.

We are slowing down.

Cassini would have to use its main engine for a very large burn

to break into orbit around Saturn so it was a tense moment.

We'd be crossing the ring plain as well which has some element of hazard to it.

Go ahead, Com.

The Doppler has blacked out.

OK, we have burn complete here for the FY orbit insertion burn.

That was a big moment,

and then once it was in orbit then everything was just quiet and

basically following the script just the way it was supposed to.

It would actually be a little over six months before Huygens was delivered to Titan.

# Oh, the weather outside is frightful

# But the fire is so delightful

# And since we've no place to go

# Let it snow, let it snow let it snow. #

Christmas Day 2004, it was the day

of the planned release of the Huygens probe from Cassini.

Basically there were a set of explosive bolts that released

Huygens, and a set of springs pushed it off on spiral rails

that gave it a spin to stabilise it.

Everything was pre-programmed on Cassini,

we were monitoring it and it went fantastically.

From that point on, Huygens was on its own, completely autonomous.

It didn't even carry a radio receiver,

so from then on if we'd wanted to change something we couldn't,

we were completely powerless.

The die was cast from that point.

When I got into the control centre, basically everyone I met was as

excited also as nervous as I was about the whole mission.

There was an enormous air of expectation,

it had been building up for the last few days.

We went into the science room that morning knowing that

whatever was going to happen was going to happen, this was the day.

Some people had said Oh, nobody will be interested in this,

but by this time we had something like 300 of the world's press there

waiting to see what would happen.

There was lots of vans and TV cameras parked outside

and anyone who could be grabbed by media guys were getting grabbed.

There was a little bit of a siege mentality,

a scientist was kind of walled away in our little room.

It was hard to concentrate on the important work

and not get distracted by all the calls for your time.

I couldn't stop thinking that about 1.5 billion miles away

out there, there was something that I had built about this size,

and it was hurtling through space at 20,000 mph

and it was about to get a rude awakening.

The plan was Huygens would hit the top of Titan's atmosphere

at a speed of 7 km a second.

Over the next two minutes it would slow down to about 400m a second.

At that point, Huygens would deploy the first of three parachutes and that

would enable it to float down to the surface at a relatively slow speed.

Then the six scientific instruments would be switched on

to really perform their job that they'd been waiting for

for about seven and a half years.

Around 10:30 in the morning, a rumour comes through

that one of the largest radio telescopes on the Earth

has picked up a signal directly from Huygens.

It looks like we've heard the baby crying.

We still can't understand what it tells us,

but clearly it tells us that the probe is alive,

the entry has been successful, we are on the parachute,

and the probe is transmitting.

The project scientist Jean-Pierre Lebreton announced that news and

there was a huge cheer, it really meant a lot to all of us.

We knew that the most critical part of the mission was successful.

It is absolutely fantastic news.

It's like hearing the ringing tone on the phone,

it tells us the phone is working.

There's no information on it yet but it's absolutely fantastic.

That was great news because it means that it wasn't gone

without trace, that even if we didn't get all the data back

or if the probe didn't make it down to the surface, at least there was something.

We have a signal meaning that we knew that Huygens is alive,

so the dream is alive.

Though it really encouraged us, we still had a long time to wait.

The real scientific data wasn't expected

till halfway through the afternoon.

We were expecting to get the data

at around 17:25 Central European Time,

so we were gathered in the main control room,

there was lots of banter, lots of discussion,

people were excited, people were talking.

As we got towards the time, we were watching the screens,

I noticed that things were starting to get a bit tense.

I was just listening to some of the discussions on the voice link and there was something

that concerned me, there was a missing command,

and I knew that for some instruments this was

going to be a technical problem,

we were maybe going to have some system problems and lose some data.

So that really ramped up the nerves after we've had the really good news

and we know the probe itself is worked, had we lost the data?

17:25 came and went, nothing, absolutely nothing on the screens.

I can remember my mouth going very dry

and it got very quiet in that room.

OK, maybe I've got the time slightly wrong, is my watch exactly right,

and for the first minute it

wasn't too much of a concern and then you could feel the tension in the room building.

I really had visions now of the last 17 years having been wasted.

Something had happened to our probe,

parachutes hadn't deployed,

the probe had burned up, the transmitter had malfunctioned.

I really imagined us staring at blank screens.

And then, and I think it was about six minutes later than we expected,

suddenly there was a shout and I looked up and I could

see on the screen in front of me one of the columns

where we were expecting data was full.

This was real data coming through from Huygens.

It was absolute huge relief to see the screens light up

with colour and display.

You could just feel the tension pop in the room.

People could start seeing from the data various

aspects of the descent, they could tell what speed we were falling at.

After a while, somebody said you know we've had two hours of descent,

I mean we must be getting close to the surface.

My instrument, the Surface Science Package, its main aim was

to make measurements for however long we lasted on the surface.

We were told initially anyway to plan for three minutes on

the surface only, so we designed it for all of our measurements to be done in that very narrow timeframe.

If we didn't reach the surface by 151 minutes then actually we'd time

out into surface mode, which would be disaster because we'd actually

lose some of our major data,

and the probe was descending way, way slower than anyone expected.

SSP, can I have a status report?

'OMSSP, status nominal on B.

'We think we've detected surface.'

In the end we had just over three minutes spare when we hit the surface.

I came back into the support area and heard that the data had been

delivered and so I went up to my colleagues and I wanted the data.

It was on a stick, so I was Who's got the stick, give me the stick!

I ran into the lab,

the guys were there clustered around one single PC screen and just as I

got there and I was about to ask the question, Do we have data yet?

the screen burst into life and we saw every single sensor had worked.

We'd got effectively a perfect data set, and the boys were ecstatic.

There was tremendous outpouring of emotion in that room

and I have to say that I did go off

at one point into the corner and I...

I was crying, frankly. It was I think the release of all that emotion

after all of those years.

We'd been through so much together.

'So we are the first visitors of Titan, and scientific

'data that we are collecting now shall unveil the secrets.'

A few of the guys were looking just at the impact data

and looking at the penetrative data,

and there was a distinct spike right at the start of the signal.

We've hit something hard, it's as if we've hit a crust on the top,

and then after that the material below is much softer and we've pushed into that without much resistance.

We had to make a chart for John to present to the media at the press conference later that evening

of what the possibilities were and we sort of wrote,

"Well it could be sort of like packed snow or maybe

"sort of wet clay but there's this extra spike at the beginning

"so maybe there's a crust."

And one of my team actually has suggested an alternative analogue and

this is because of the crust perhaps we see there,

and that is creme brulee,

but I don't suppose that will be appearing in our papers.

And the media just love that, it was a headline in Nature magazine

that week, "Titan Team Gets Its Just Desserts with Creme Brulee Surface"

or something so that was really good PR coming up with that analogy.

We can report that the Surface Science Package collected data

for 3 hours 37 minutes.

Apart from any scientific and engineering importance

of that figure, some of you might have heard

that we had a sweepstake in our team for the moment of impact

and I'm slightly embarrassed, I have to tell you,

that it was I who won the sweepstake

and the prize, which was a very old bottle of Scottish medicine...

..was consumed by the team at about 2:30 this morning.

John put in a good bet,

he was 10 seconds off on a two and a half hour descent time, that's

almost a magical touch I think.

Oh, no, it seemed actually entirely appropriate.

I mean he was the leader, he was the guy that made it all happen.

There was barely a single day since the project had started

when I hadn't tried to imagine what the surface of Titan looked like.

I remember the first few images that we saw were quite remarkable.

We saw this landscape carved with what look like river channels.

The theory there had been liquid

on the surface of Titan was true,

it was absolutely amazing to see it, the first people to see that image.

Also it struck me that it looks so much like Earth.

It looked like Arizona, it looked like the French Riviera,

it looked familiar and that wasn't something I think we were expecting.

And then we saw the landing image,

the area immediately around the probe.

It was an area that seemed to be strewn with boulders and I

just couldn't believe that our probe, that we of course knew so well, and

my beloved instruments on board, were actually sitting quietly, serenely,

on this surface environment.

What we've learned is that Titan's surface is incredibly varied.

It shows features which show some similarities,

at least superficially, with Earth.

We're now pretty certain that we see lakes and seas of liquid methane.

There's a whole range of geophysical processes going on that's shaping the surface of Titan.

We've learned an enormous amount about the atmosphere.

We have a stratosphere, we have a troposphere,

we have weather, we have weather on Titan.

I think it shows our sphere

of influence, if you like, our sphere of knowledge

expanding beyond the Earth.

Our machines have put their foot on the surface of Titan.

We've shown that we can do it.

It's part of that process of exploration

that I think we've always done.

It's part of what defines us as human beings.

To get closer to the Mission to Titan and explore the stars yourself

with the Open University's Virtual Planisphere, go to:

Follow the links to the Open University.

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