[MUSIC PLAYING]
Mars is our next door neighbour.
And so the one massive, resounding question
that obsesses me is, does Mars have life?
For a long time there's been this idea,
has there been liquid water?
If it's got liquid water of course,
it's long been understood that's one
of the prerequisites of life.
When we're exploring Mars, we don't do it in person.
We don't send human astronauts, at least not yet.
And we send our machines.
We send robotic explorers and beam back all that information
back to us, so we can piece it together and learn
as much as we can about this other world.
So if you want to design an instrument for Mars,
for operation on Mars, there's some key things
which you have to bear in mind.
It needs to be low mass.
It needs to be lightweight and compact.
Even just to launch mass into low Earth orbit,
I believe it costs something like 20,000 pounds per kilo.
If you want to get the equivalent
mass to the surface of Mars, it costs an awful lot
more than that.
It needs to be able to survive the vibration of launch.
It needs to be able to survive high radiation environments.
And an average surface temperature
is something like minus 60 degrees
centigrade, so you got to operate Curiosity and all
these instruments under these extreme conditions.
Obviously, it's nice to see it as a challenge.
And it's amazing what can be achieved.
You put it in the pointy end of a massive firework,
launch into space where it travels through the very
brutal and an unforgiving environment,
and then arrives at an incredibly high speed.
So you've got to go from 6 kilometres per second to 0
in 7 minutes, that's the challenge, landing
this 1,000 kilogramme rover.
And not end up burying your years of working
and your millions of pounds worth of equipment
and hardware in a smoking crater.
It was a bit of a step into the unknown.
Touch down confirmed.
We're safe on Mars.
That's when the exploration starts.
A sol is Mars for a day.
It's about 24 hours and 37 minutes.
We have to get our instruments up to a working temperature,
so we only work after 11:00 AM local time on Mars.
But if you want to get the most out of your rover
and your science and engineering team in the first 90 days
when don't know if things are going to last,
then it's best to switch to Mars time into the rhythm
that Curiosity has to go through.
What that means in practise is that every couple of weeks you
end up working at 2 o'clock in the morning.
But that was OK.
No one was complaining because we had our fantastic
rover on Mars that we were operating.
Some people got watches made to run on Mars time.
So if you ever see anyone around Pasadena with two watches on,
then you know they're working on a recent Mars mission.
Since the 17th century and the first telescopic observations
of Mars, we've got to learn our neighbour,
this other world much, much better.
We have high resolution colour images.
We have stereo images so we can get accurate distances
and elevations.
And we have chemical and x-ray diffraction data.
So we take all those different data sources,
work out what's been happening on Mars from billions of years
ago right up to the present.
And then, we discuss on the telephone
what we think of the data and what we need to do next.
So we might decide well, that's a really interesting outcrop.
Maybe there's some sign of water there.
But we need to get another image.
We need to get a high resolution image.
Perhaps we need some x-ray diffraction.
And we make a plan for next day and a longer term plan.
Then, we make sure that we've used an appropriate amount
of power and the data resources are OK.
And then, we upload it to the rover.
And so the cycle repeats.
I'm an astrobiologist, and my thrill
is into looking into the possibility of their being life
on Mars.
And we're not, obviously, talking about little green men.
We're talking about hardy, microbes
called bacterial lifeforms.
And then, that's going to be hard to find.
And actually, one of the bigger questions
is whether the environment on Mars
was ever conducive, was ever clement for life.
We need to look at the rocks and see
under what processes they formed.
And to do that, we use tricks like x-ray diffraction.
So we take our sieved material, for instance, from the drill,
and we put it onto a little vibrating stage.
Vibrating this fine grade material,
we make sure we got an even mix of all the different minerals
and all their different crystal orientations.
The CheMin instrument takes a source
of x-rays focused through a pinhole.
Then, we direct it onto the stage.
A very narrow beam of x-ray.
It's almost like a torch shinning not with visible light
you can see with your eyes but x-ray light.
And you collect the x-rays, which
have defracted through your sample.
Focused onto a CCT, bit like at the back
of your digital camera.
And what we get there are these rings, called Debye rings,
and measure the radius of those rings using something
called Bragg's Law-- so that's going back
to beginning of the century-- allows
us to measure the spacing between different layers
of atoms.
And that's the information.
It tells you what kind of mineral or what kind of rock
you're looking at.
And on Mars, some of the minerals,
it's about one nanometer.
That tells us it's clay.
It was this kind of stuff.
This is modellers clay I've got here.
It's the kind of thing you might play with and make things out
of.
It's a very commonplace material on Earth,
but to find this on Mars is absolutely mind-blowing.
This is clay that was formed in an aqueous environment.
And so what Curiosity had essentially found
was river mud, the mud on the bottom
of what would have been a babbling brook
billions of years ago on an ancient Martian surface.
And the conditions needed to make this clay
would have been not too acidic, not too alkaline, not
too salty.
And, in fact, if you could have jumped
into a spaceship and a time machine
and gone back to that place on the surface of Mars
billions of years ago and knelt down
and scoped up some of that water in a glass,
you could have drunken that Martian river water.
It's only really because of Curiosity
that we know we've had these long-standing bodies of water,
lakes, which lasted for thousands of years.
The same technique that solved the structure for salt in 1914
is being used today to help in the search for life
on other worlds.
I don't suppose they could possibly
have imagined that x-ray diffraction would
be used on Mars.
But it shows just how important the work was that they did.
With all of this space exploration
and trying to get to know other worlds,
you're obviously always trying to push back
the very frontiers of what we know already
and what we've been able to achieve in the past.
And you can't always play it too safe,
and you have got to take risks.
You've got very little chance, or no chance at all,
of being able to repair an instrument which
isn't working properly.
The answer to this is really lots of testing.
You have this building accumulation of knowledge.
And this helps us decide the most exciting places
we want to go to next time.
Mars 2020 is an interesting mission
because that is likely to be the first part of Mars sample
return that we can take back to Earth to do all sorts of tests
for presence or past presence of life.
For me, I think having mankind in space
is about the spirit of exploration.
There really is an awful lot that you
can do with machines like Curiosity.
I think that, in the end, you have to do both.
And, ok, you can get instruments to the surface of Mars
at significantly less cost, but, ultimately, there's
a limit to what you can really do with machines alone.
And sending man there, you'd have so much more flexibility.
And you can make decisions right there and then
with a trained eye.
And I think that opens up massive possibilities in terms
of science that you can do.
I would love to go.
But, yes, I'm probably not young enough anymore.
it'd be a really major challenge just
for these people to survive.
And that could happen as early as the 2020s.
So there are possibilities there.
In terms of a space agency sending people there,
then they're going to want to bring them back.
And 2030s is probably the earliest
that that could realistically happen.
So if you'd been a microbe on Mars four billion years ago,
yeah, it would have been habitable for you.
We don't yet know if there were any.
Whether it did support life is the next stage.
To think of the cosmos as a whole,
and there are grand questions to which we, at the moment,
we don't really have much idea about.
So, for example, things like why is the universe here
and how did it originate and-- OK, there is a simple answer
if it originated in the Big Bang.
But, why did the Big Bang occur?
And, of course, day to day, I'm working
on much more mundane things.
But, in many ways, those are the things
which ultimately motivate me to work in space science.
My long-term hope is we get closer
to finding life on another world because I think
that would be one of the most fundamental and revolutionary
discoveries that we could make as a species.
We know that we're not alone in this universe.
It is necessary to put in big effort
to get some worthwhile harvest of knowledge.
You have to be prepared to go a long distance .
Of course, we went a very long distance,
over 60 million kilometres to Mars,
and used a lot of resources, both financial and manpower,
but I'm confidant it's all been worth it.