Just a few days ago the ExoMars Trace Gas Orbiter started to sample
the thin Martian atmosphere looking for the signs of life.
Our desire to find it means that we've invested heavily in this
search, in terms of time, money, but also emotion.
And now, the Red Planet is even being talked about as a potential
second home for the human race.
But isn't it time we faced reality?
That Mars is a dead planet,
and destined to stay that way.
Welcome to The Sky At Night.
Mars, our nearest neighbour.
There are many reasons why we are fascinated by it.
But one question towers over all the others -
is there today, or has there ever been, life on the Red Planet?
On tonight's programme we explore the latest results
and ask, is Mars a dead planet?
And if so, what are the chances that the first life on its surface
will be us?
We'll be catching up with ESA's
current mission to our nearest neighbour,
the ExoMars Trace Gas Orbiter.
And also discovering how to build a rover that can survive and operate
in the planet's brutal environment.
Pete will be showing us how to get the most out of observing Mars
in the night sky.
Hello.
And I'll be talking to Andy Weir, author of The Martian,
later made into a Ridley Scott film, about the difference between his
fictional human mission and reality.
The exteriors were shot in Wadi Rum, Jordan. It looks like Mars.
But we start with the very latest and most detailed pictures to come
back from the Red Planet, and find out what they're telling us about
the possibility of life on Mars.
In 2012, Nasa's Curiosity rover landed on Mars
like something straight out of Thunderbirds.
And it's been working hard since then,
sending us amazing panoramic images of the planet's surface.
And these reveal that Mars was not only once a wet world,
but that it was wet for far longer than we thought.
I'm here at Imperial College's data science Institute to talk to
Sanjeev Gupta, who's one of the Curiosity team.
Sanjeev, hi, it's wonderful to be here in this amazing facility.
Oh, there's Curiosity.
So Curiosity's first goal is actually the goal of habitability.
Were there conditions on ancient Mars that were suitable for life
to have formed in, existed in, and been preserved in?
Were there the right chemical ingredients?
All of these sorts of things.
So where on Mars are we, and what are we looking at here?
So we are sitting in Gale crater -
this is this crater that's about 150km in diameter
that sits at the Martian equator.
What we've got here is this incredible mountain.
This is Mount Sharp, it's 5km high, and it's made up
of beautifully layered, stratified, sedimentary rocks.
You can see that on this image here.
You can see those layers working their way up the mountain.
That's right, these are sedimentary layers.
And what these are recording is basically progressive build-up
of sediment on the Martian surface.
OK, so something's depositing regular layers of sediment.
OK, let's have a look. We can add the next image, there we go.
It's coming. Coming up!
It's a big image. OK.
The rock is actually a mudstone, it's a very, very fine-grained rock.
And we interpret these layers to have actually formed in an ancient lake.
So each layer is a season, or something like that?
We don't know whether it's a season, but it's a depositional episode in a long-lived lake.
So long-lived is important, right? Because that tells us
that not only was there water on Mars -
there was water on Mars that persisted for quite some time.
That's right. We've got hundreds of thousands, if not millions
of years of sedimentation in a long-lived lake.
What Curiosity has discovered is evidence of lakes that may have
existed long enough for life to evolve.
But its images also reveal that conditions necessary for life
may have survived even after the lakes disappeared.
OK, well, let's have a look at one of the more recent images.
Oh, there we go. And here we are.
This ridge is probably three or four metres high here, in this face,
and just gorgeous detail in terms of the geology.
This finely layered detail which you can really see in these layers,
and then these cracks as well.
We've been able to use the rover's instruments to actually look at the
chemistry of the crack fills,
and actually they show evidence of calcium sulphate so this is actually
gypsum that's filling these cracks.
And this tells us an interesting story about Mars.
After these rocks were lithified, they were turned to stone,
they were buried and then there was ground water flow
through these rocks
and that ground water was full of calcium ions and sulphate ions,
and did deposit it within those crack fills.
The interesting thing about this is that the chemistry,
the chemical changes, are important to habitability,
and that's really crucial. That's why there's
so much interest in this. About whether there's life here.
The big result from Curiosity is that we have these long-lived lakes
that provided the conditions that were suitable for life,
if it had ever arisen.
Well, it's wonderful to see these images,
lovely to spend some time on Mars.
And I'm looking forward to seeing where Curiosity goes next.
Good luck. Thanks very much, Chris, it's been brilliant.
Whilst Curiosity continues building a detailed history of water on Mars,
it's not looking for direct evidence of life itself.
For that we have to wait for the results from a European mission.
In 2016, the ExoMars Trace Gas Orbiter was launched from Baikonur
in Kazakhstan on a seven-month journey to Mars.
Since arriving, the TGO - as it's known to its friends -
has been decelerating and entering a circular orbit through the thin
Martian atmosphere.
It finally reached that orbit
a fortnight ago to start its mission...
Trying to confirm if plumes of methane exist above
the planet's surface - because this is a potential sign of life.
I'm here with Manish Patel,
one of the lead scientists on the European Space Agency instrument
on board, to tell me what TGO is hoping to discover.
Manish, it's taken a long time to get there and now it's finally
in orbit. How excited are you?
Incredibly excited. I've put a lot of my own personal life into this
mission and this instrument.
So getting this here to where we are today has taken ten,
15 years of my life,
so I am incredibly excited to get this first data from Mars.
So you're talking about getting data -
how are you going to get it and what are you looking for?
ExoMars TGO is called the Trace Gas Orbiter,
so it's looking for trace gases in the atmosphere of Mars.
So by looking for these trace gases we can start to unlock the secrets
of what's going on on Mars, what's going on below the surface.
The most exciting one is methane.
So this is a very controversial gas on Mars.
Basically it shouldn't be there, it should be destroyed by sunlight.
The fact that it's still there now says something is creating it.
What levels of methane are we talking about? What concentrations?
On Earth we have methane in the order of parts per million
in the atmosphere.
On Mars, it's going to be at the level of parts per billion.
So imagine a box full of a billion gas molecules and one of them
might be methane. That's pretty hard going, I mean, to actually be able
to home in on to the one... And you can do that with spectroscopy,
by looking at the light? Exactly.
By looking at the sun through the atmosphere, we can look at the spectrum.
And it's these missing colours which tell us which gas molecules are
absorbing that light and therefore that are present in the atmosphere.
So if we do detect methane, what does it mean?
There are different ways of making methane on Mars.
One is not involving life, so geological processes for example,
the action of water and rock below the surface.
So that's one kind of less interesting process of
creating methane, if you like. Sorry if I offend any geologists!
But the other method that may be occurring on Mars that we have
on Earth is the production of methane by life.
What sort of life do you think we are talking about?
A lot of the methane on Earth is created by organisms.
This is an intriguing possibility.
We're talking about microbial life, potentially.
If it's existing on Mars, microorganisms below the surface.
Because I guess with the surface, if it's radiated by too much UV, nothing could survive there.
It's a very harsh environment. But what's going on below the surface is a whole other story.
That's where the real domain for life is believed to be now.
So there is the possibility for a nice, warm, benign environment
below the surface, where you can have liquid water.
Then the methane is leaking out from underneath the surface.
Possibly, yes. What's more likely in my personal opinion is that life may
have once existed on Mars but what we are seeing now is the exhalation,
if you like, from below the surface of these signs of past life.
Well, please do come back in and tell us the results as they come in.
Because it sounds like an exciting project and I think people across
the world want to know if there is life out there, so we're all behind you. Thank you.
The ExoMars TGO will be orbiting for the next five years,
and it is hoped it will detect those traces of methane.
Unfortunately, the satellite itself won't be able to say definitively
if the source is geological or biological,
from microbial life beneath the surface.
But the TGO orbiter is not the whole mission.
In 2021, the TGO is going to take on a new lease of life,
acting as a relay station, sending data back to Earth from this,
the ExoMars rover.
Later on we'll be talking about what it hopes to find and how it's going
to cope with that hostile Martian environment.
But first Pete Lawrence shows us how to explore the planet
from here on Earth.
Mars is a fascinating planet, and when it's above the horizon,
it's easy to see with the naked eye.
But to get a better look, you need some magnification,
so I've brought with me a ten-inch telescope
and I've got a high frame rate planetary camera fitted on the end -
that's like a souped-up webcam - and that's connected to a computer
and that will give me a view of Mars on the computer screen.
As Mars is low on the horizon tonight,
the atmosphere affects the image quite a bit,
making it jump and dance.
This adds to the challenge of spotting features.
Now I did manage to get a capture of Mars earlier on when there was a gap
in the weather. And you can definitely make out the gibbous
shape of the planet which we can see at the moment.
But atmospherics are against me this evening because I had also hoped to
see a dark V shape.
That's one of the most prominent features on Mars you can see through
a telescope, it's a feature known as the Syrtis Major.
Syrtis Major is a region dominated by a volcano and it's also where
evidence of methane is thought to be found.
One of the other features you might notice are the icecaps on the north
and south poles.
And then there are other dark patches.
Before we sent any probes to take a closer look,
some thought the dark patches could be vegetation,
and the subtle changes in the shape of these patches could be due to
vegetation growing or not, perhaps with the seasons.
We now know that the dark patches are exposed areas of rock and the
the shape of the dark patches,
sometimes obliterating them completely.
Mars is pretty tiny at the moment but over the next few months
as we head towards opposition at the end of July,
it will start to get bigger,
and that's when you should be able to see some surface features on it.
So get out there and enjoy the view.
In the quest to find life on Mars,
there are many future missions planned.
But for me the most exciting happens here,
in the Mars Yard at the Airbus space factory,
just off the A1 near Stevenage.
The ExoMars rover.
This machine will need to endure some exceptionally hostile
conditions when it lands in 2021.
To get an idea of how hostile, our online stargazing weather reporter
Elizabeth Rizzini reports on conditions today
in the rover's planned zone of exploration.
So let's take a look at today's forecast then. It was a beautiful
sunrise, just a bit of wispy high, thin cirrus cloud up there.
That should develop into some very pleasant sunny spells, I think,
as we head through the rest of the day.
Of course it's going to stay dry and we're looking at temperatures up to
a balmy -23 Celsius, but a scorching 7 degrees on the ground.
And then overnight tonight I think we'll see some fog form,
temperatures down to a bone-snappingly cold -80 Celsius.
But that's not as cold of course as it is at the poles,
where we can sometimes see it snow carbon dioxide.
Just a gentle breeze around today, but the winds will pick up
if we see one of these dust devils form.
In fact around the outer edges we could be looking at some gusts
of up to 90mph.
But at least that helps to lift the dust from the solar panels of the
rover. Now all in all we've got some very pleasant late summer's weather
around, so enjoy your Martian day.
It is said for every scientist working on a project,
there are ten engineers making it happen and, in this case,
they really have their work cut out.
Paul Meacham explains some of the unique challenges of making a rover
that can search for life on the Martian surface.
Mars is a really hostile environment compared to Earth, so how is
the rover designed to cope with that?
It starts with the extremes of temperature that we see on Mars.
In the day it can be up to about 10 degrees in the Martian summer...
That sounds quite nice. Yes, it does, yes. But at night-time,
because the atmosphere is so thin and doesn't retain heat very well,
it can get down to as low as -130 centigrade.
Whoa. OK. That is a bit nippy.
Yeah. And in most electronics that are sat on the rover,
nothing special particularly -
They are the same as electronics we would find in a mobile phone
or in a computer... They're not designed for that environment?
No, that's right. What we have to do instead is create an environment
inside the rover, so that the electronics will like it.
OK. Sort of a warm, dry...
Yeah. So it can operate at sort of...in normal conditions?
That is right, yeah. Typically about room temperature inside the rover.
I see.
This just looks like a giant sandpit but how close is it to the
Martian surface? It is actually surprisingly realistic, actually,
in a number of key ways.
The first is the sort of sand we have in here -
it is deliberately picked that it is the sort of correct range of grain
sizes. It is also extremely dry in the way that Martian soil is.
The sort of terrain you see in this Mars Yard is fairly typical of the
terrain we expect the rover to be able to handle.
The locomotion system can handle a rock up to 25cm tall which is about
90% of the sort of rocks we expect to encounter and it can handle any
slope up to about 26 degrees
with this rather flexible locomotion system. OK.
And I suppose if it encounters anything higher than that,
it will sort of go around or take another route?
That is absolutely the goal behind the autonomous navigation system.
So autonomous navigation, does that mean that the robot isn't being controlled from Earth?
Yeah. The time delay between Earth and Mars can be as much as 20 minutes.
It is really not practical or safe under some circumstances to drive
the rover remotely. Instead you want the rover to make as much of the
decisions as possible and decide for itself where is safe and where is
not. What would be success for you?
It would just be to get the rover down on the surface, driving around,
just to think something I worked on would one day be on the surface of
Mars operating, that would be the success for me.
And I guess success rates of getting things to the Martian surface has
been a little hit and miss in the past? It has. Yes. It is about 50%, I think is the figure.
With such a thin atmosphere...
..it's not actually easy to predict what the atmosphere is going to be
like during the descent and that means every time you go down it is
slightly different from how it was the time before.
So there is some jeopardy there?
For sure. And we tend to refer to it as the seven minutes of terror.
Because you don't really know what's happening,
you're seeing everything with a time delay on it.
Well, like you, I just can't wait until it's successfully on the surface and getting data.And please
do invite us back because we would love to see what it's finding. Of course. Thank you.
Once the ExoMars rover lands safely,
it will slowly truck across the planet's surface,
hunting for elusive evidence of past life.
Peter Grindrod, a researcher on the rover team, is here to explain the
unique approach it is going to take.
So we have this marvellous rover, where do you send it?
Where are we going? The first thing we have to do is use the constraints
from the way we have to land on Mars.
You know, we have to land near the equator,
we need to land at a low elevation to give the parachute time to do its
work. So that rules out about 98% of the planet to start with in terms of
the engineering. And now the 2% left we have to try and find a really
good scientific area or target to find,
and we've narrowed it down to two.
Quite close together, in an area called Arabia Terra.
And we're hoping to find nice, soft sedimentary rock.
We think these sediments are probably going to concentrate
the sort of evidence the ExoMars needs to look for.
And so, ExoMars,
one way to think about it is that it is a robot geologist.
So what experiments will it do that will tell us about this landscape?
We are going to try to drive ExoMars as best we can to replicate what a
field geologist would do.
At first, you open your eyes, we have the cameras.
We'll look around and try to find good targets and then we will figure
out the safest way to drive to those targets.
We can use other instruments like ground-penetrating radar to look for
layers which are also evidence of sedimentary rocks.
And then the ultimate end goal of this is to find a target that we
can drill down with our deep drill core.
And that's never been done before. We've never drilled under the surface to get a sample from Mars.
In terms of life and organic material on Mars,
the surface isn't a great place.
It is bombarded with radiation, it can break down the organics.
We want to get down through that layer.
We're hoping to go down to two metres.
The models show that about two metres down should be protected by
all the rock at the surface.
And so the organic chemistry down there will be preserved as it was
at the time of formation, we hope,
and hasn't been broken down to hide the evidence of life.
There is a pristine piece of ancient Mars?
Exactly, pristine. Yep.
It is hard in my head not to think that you're going to dig down
and pull up some green slime or something and go,
"Look, life is there."
It's not going to be that simple, is it?
I think we are going to collect a nice-looking sedimentary rock
and when you look at it normally that might look quite boring but I
think once it's turned over to the instruments onboard the rover,
that is when they become interesting.
When those can look for the complex chemistry,
the organics that are present, then I think it'll be exciting.
But we're not going to be seeing anything as exciting as green sludge.
If I have to push you, what do you think the chances are?
Do you think we will find complex organics,
the kind of things that might suggest there was life there?
Well, being honest, I don't know.
I mean, that is why we are going there.
Everything on the Earth has shown that wherever we go,
the extreme conditions aren't really a hindrance to life.
We still find life everywhere on the Earth,
so though I am unsure about what the results will be,
I am hopeful that we will find evidence of life.
However, the way that we explore and try to find the life with rovers,
with robots, is inherently more difficult than using humans.
It is easier if you can get a big sample in the lab.
Of course. And ultimately this should be one of our aims.
Because if we go back to the idea that extraordinary claims will
require extraordinary evidence,
now, finding life on Mars is undoubtedly going to be one of these
extraordinary claims.
It may be that we have to bring back samples from Mars and put them into
our labs on the Earth. So ExoMars is just the next step in a very long
process of looking for life?
Absolutely. Well, it is going to be
a exciting mission, whatever you find.
Pete, thank you very much.
We may hope to find living organisms on Mars but it is likely that the
best that we can expect are traces of ancient microbial life that once
lived billions of years ago, when the planet was wet.
But even if it is lifeless,
that hasn't stopped people dreaming of going there
and making it home.
This Mars Yard may be as close as I ever get to the real Martian surface.
But there are many people out there thinking differently.
What seemed like a crazy pipe dream just a few years ago is being taken
very seriously by some.
The future is vastly more exciting and interesting
if we're a space-faring civilisation and multi-planet species
than if we are not. We can complete the ship and be ready for launch
in about five years.
Five years seems like a long time to me.
APPLAUSE
Missions to Mars, planned colonisations?
Chris met up with someone who knows a thing or two about this because
they literally wrote the book - Andy Weir, author of The Martian.
Hey. Andy, it's Chris Lintott here.
How are you? I am good, how are you doing?
Excellent, thank you.
The Martian described a future mission
and suggested we could live there,
by growing potatoes in our own poo,
a suggestion memorably recreated in the film of the same name.
FILM: I now have 400 healthy potato plants...
So you had the great privilege of seeing the world you'd imagined
turned from a book into a film.
What was it like seeing the places you'd described represented on film?
Do you think they did a good job?
Oh, it was just an amazing job on the film.
There is only so much you can do with narrative fiction and
describing scenery. In fact, I tried not to do it.
My editor made me put more of that into the book because I'm like,
"What? It's a bunch of freaking red hills."
But in the film, such an intensely visual media, oh, my God,
Ridley did just an amazing job.
The exteriors were shot in Wadi Rum, Jordan.
It looks like Mars.
It did make me think that part of the fascination of Mars is that
those landscapes are very human, they could be Earth-like.
Do you think that familiarity has something to do with the appeal?
Well, yeah. I think people are interested in Mars largely because
there's a certain vitality to it.
It has... It has an atmosphere, it has weather, it has seasons.
It has precipitation.
Everything you've come to expect from a planet.
I know you've had, let's call it feedback,
from every scientist who's read The Martian.
How do you think you did? So, I like to...
I like to use real science and physics in my books because it's
already an internally consistent system but, yeah, I've had people
e-mail me, you know, saying,
"Oh, you made a mistake here, you made a mistake there."
That's great because, you know,
if I set myself up as, "Hey, I'm giving you an accurate
"science story," then I invite that sort of criticism.
I've got to ask you about dust storms, I'm afraid, because
obviously there's that dust storm that's critical at the beginning.
What would it be like to be there? You can put the record straight.
What would it be like to be in a dust storm on Mars?
Basically Mars does get winds up in the 150kph range but the
atmosphere of Mars is so thin that the momentum behind those winds
would feel like you are kind of standing in a 1kph breeze.
It could barely knock over a piece of paper,
let alone a 27-tonne spaceship.
COMPUTER: Warning... We are at 10.5 degrees.
Excessive tilt. Tilting to 11.
That one was less of a mistake and more creative licence.
I knew at the time that I was writing it that it was BS.
For British viewers, that's rubbish, I think is what you mean.
Rubbish. Yes. I went ahead with it anyway.
It is a person-versus-nature story,
and I wanted nature to get the first punch in.
Yeah. So why -
given that we want to believe that human ingenuity will win out -
why haven't we gone?
Why is all the discussion about the problems of going to Mars?
Why hasn't it happened yet?
Because it's incredibly expensive.
It's really hard to justify that expense.
But I don't know, wealthy nations throughout history sometimes just
build awesome stuff because it is awesome and for no other reason.
I mean, for the US, it's the Apollo programme.
For the ancient Egyptians it was pyramids.
You know? Maybe we will build some pyramids on Mars at some point,
just to say we were there.
Andy, thank you very much for talking to us.
It's really appreciated. Thanks for having me.
Mars has always meant a lot to us.
It has been the home to countless stories,
and the target of many probes.
The first human mission always seems to be ten or 20 years away,
delayed by arguments about money or discussions about the technologies
that need to be developed to take us there and keep us safe on the
surface. But despite these problems,
I can't let go of the idea that it would be amazing to step out and
explore this wonderful new world.
That's all we've got time for this month.
But do go on the website and check out Pete's star guide.
And also go onto Twitter,
see Lizzie's Sky At Night weather forecast.
Next month, we'll be discovering how the Gaia space telescope is
transforming our understanding of our local galaxy, the Milky Way.
In the meantime, it's goodnight from me...
..and it's goodnight from him. Goodnight.