- One of the reasons that I am most curious about Mars is
I wanna understand what makes a good habitable planet.
Why do some planets sustain life for billions of years,
teeming with life, like our own Earth?
Mars once had an environment that was much more hospitable
to life, but then it, as a planet, lost it.
Why, what happened?
Why did it change?
By exploring these sister worlds, we really learn something
about how fragile the balance can be,
because it tells us how rare or how common places
like Earth are in the universe.
- Houston, Endeavor, roll program.
- Join me as we look into some of the space explorations
that so excite us and have such promise
for improving man's environment
that we dare not ignore them.
- Right now is one of the most exciting decades
for space exploration where some of this science fiction
about having humans in space, on the moon, on Mars,
I think that that's starting to become a reality.
My name is Bethany Ehlmann.
I'm a professor of planetary science
and I do research at the NASA Jet Propulsion Laboratory
where we operate the rovers on Mars.
- Touchdown confirmed
safely on the surface of Mars.
- I'm fortunate to have really what's one
of the coolest jobs in the world.
It's easy for me, to some extent,
to talk about what I do because, you know,
everyone kind of likes space.
I mean, when you're a kid, it's like space and dinosaurs.
Those are the cool things about science.
- In a universe of billions of stars,
there are billions of mysteries.
What is the origin, age, and evolution of the universe?
- Planetary science kicked off in the '60s, the '70s,
with the first missions to Venus, Mars,
humans landing on the moon.
We're able to do so much more now.
Most people don't know the incredible number of things that,
you know, we as a human species are now doing in space
and what lies on the horizon.
We're able to land car-sized rovers on Mars
and then operate them.
We're able to send spacecraft to fly by Pluto,
farther than people would've believed 50 years ago.
And we're seeing also this tremendous growth in industry,
commercially, with rockets, with satellites.
We are really seeing the democratizing
of space exploration.
The European Union has a space program.
Russia has a space program.
Japan just returned a sample from an asteroid.
India and China and the United Arab Emirates
all have missions orbiting Mars.
There's so many countries involved right now.
I think we're really becoming a space fairing society
and it only enhances our exploration.
So it's an incredible time to be a space scientist
and to be an explorer.
- About 16 kilometers from the surface of Mars.
- For it is in the quest for such knowledge that science is
bringing us closer to an understanding
of who and where we are.
- One of the most important things as we explore,
right now, is the search for life on other worlds.
Whether or not Mars hosted life is the big question.
Mars has always been incredibly intriguing
because, well, it's been the red planet.
It's kind of sticks out in the sky.
But when the first flybys were made of Mars, we saw
a cratered landscape kind of like the moon,
so it became clear it was old.
But then there were these channels,
these huge-scale features that indicated water.
And one of the fascinating things is that we look back
into deep time, we look back into the geologic record,
we see a Mars that was once far more like Earth.
It had lakes, it had rivers, it had
Yellowstone-like hydrothermal systems.
So the big question is, well, why,
and what happened to this Mars?
And then, did Mars also develop life?
Does it still have life?
My own research really focuses on using minerals
and chemistry of the rocks to trace the history of water.
So we're able to see and paint a picture
of different habitats on Mars
as they existed three and a half billion years ago.
People come to planetary science
from all sorts of backgrounds, from physics,
from astronomy, from engineering.
I come at it as a geologist, meaning I study rocks,
but I just happen to study rocks on other planets.
I love geology.
I love the sense of place, that feeling of the landscape.
And as a planetary geologist, that means I get to study,
you know, other worlds.
We can look at the planet now,
see how its atmosphere is today, try to guess,
but really, that record is actually recorded
and imprinted in the rocks.
It's the rocks that record the history.
Planetary exploration really starts
with understanding our own planet.
I'm looking for a good spot, probably best over here,
try to show the different layers in the rock
and the different environments that are recorded.
I can tell so many things about the past
just by looking at this rock.
You're effectively learning a different language.
You're learning a different set of visualizations
and characters, and you're learning to read that.
There's a record in each and every rock
about how it came to be and what the environment was
around it when it was formed.
This rock is a really neat one that records the fact that
if we had been standing here somewhere
between two and 5 million years ago, there would've been
a giant volcano going off, raining down on us.
So we're seeing change.
We have to look much deeper in time
to see what the planet was like at its beginnings.
On a human scale, a long time is,
you know, 40 years, 50 years, a hundred years.
To a geologist, that's the blink of an eye.
A long time is maybe a million years,
tens of millions of years.
The Earth is about 4.6 billion years old
and we're able to peer back deep in time
to the very beginnings of our planet.
So for Mars, what's really special is
it's one of the few planets in our solar system
where we're not going there yet, as humans,
but we can send our robots to do the same thing.
They are doing everything that we would do
in the field if we were there.
I think science, in some ways, is a spiritual calling
in the sense that there is just an awe
at this universe that we live in
at its complexity, at its beauty,
and we have the brain to understand it
and to make sense of it.
The amazing thing about scientific training is that
it teaches you how to answer the why question.
That's what I also try to teach as a professor.
Caltech runs the Jet Propulsion Laboratory,
NASA JPL, so it was sort of the best of both worlds.
I could be a professor at Caltech and work
with the engineers at JPL to explore space.
Our solar system is filled with a amazing,
diverse set of eight planets.
They're all very different from each other,
but all of the building blocks are the same:
the same chemical elements, minerals, the same ices,
but the way you arrange them matters.
Our solar system has three planets that, you know,
in a cosmic sense are pretty similar to each other.
They're rocky bodies with metal cores with atmospheres
and that's Venus, Earth, and Mars.
Venus is hotter than heck.
It is hotter than the boiling point of water on Venus
so does hard for our spacecraft to survive.
But one of the things we wanna know is did Venus have water?
Is the water now trapped in the rocks?
Is it found in the atmosphere?
What happened to Venus?
Any water that was once present
in the surface is now evaporated.
It can only exist as gas.
But Mars is Earth's smaller, like, little brother.
It's accessible, we can explore it.
Most of the missions to Mars actually historically
haven't made it or famously missed Mars.
So Mars is hard.
Space exploration is hard.
But landing a rover on Mars is particularly hard.
In 1997, the first rover, the Sojourner,
successfully landed on Mars.
It was about, you know, yay, big.
Next sent in 2004 were the Mars exploration rovers
which are about as tall as a human,
about as heavy as three humans.
The next generation of rover, in 2012, the Curiosity rover,
about the size of a Mini Cooper car.
We want to travel further and we want to travel faster.
- Touchdown confirmed.
Perseverance safely on the surface of Mars.
- And finally the Perseverance, which will
not only rove, but it is collecting samples
to bring them back to Earth,
you know, next step in exploration.
If that weren't enough, the 2020 rover
also has a helicopter.
Our work as scientist begins, when the rover lands.
- Our mechanical astronauts will take pictures,
analyze the soil, sift the strange air of Mars,
feel for moisture.
Thus, we will obtain information about Mars from the ground
up to the limits of its atmosphere.
Perhaps the greatest interest will be
in the lander's search for signs of life.
- There're literally thousands of places on Mars
where we see this record of different kinds
of water, different kinds of environments
at certain points in time.
In the spot that we've picked for the Perseverance rover
on Mars is really special to me
because it's the Jezero landing site,
is one of the very first places I studied
as a graduate student as I was learning
how to be a scientist.
We discovered this beautiful lake delta
and then outside of Jezero,
one of the most ancient stratigraphies
on Mars, 4 billion years old.
I think it's a spectacular choice.
We get to embark on this great traverse, collecting samples
along the way, that really reveal the history
during this early critical period.
Believe it or not, there's actually
a pretty mundane routine to operating a rover.
The rover doesn't like to drive until later in the day.
So typically, it wakes up and needs time to warm up.
And we have about an hour
before the rover drives to do science.
- Encryption will be one topic and...
- My day-to-day is mostly a meeting with people,
you know, talking about what we do, where we go.
- Yeah, we're in agreement on that.
- And on the phone are the scientists in charge
of the water detector from Russia.
My other science colleague, a volcanologist,
who studies volcanoes is on the line telling us
where to point the camera.
The folks from Spain are telling us
what sequences they want to run
on their environmental sensor.
So it's really a global collaboration.
All right, I guess we should do some work, right?
I'm showing you what I actually do.
So yeah, how we know the composition
of planets is by the type of data that I'm showing you here.
This is an infrared image of Mars taken
by a spacecraft called PRISM.
And this is the landing site of the Perseverance rover.
This is the Jezero Delta that we're gonna be exploring
for the next few years.
So here, I'm showing you clays and carbonates
in the sediments that make up this delta.
So this is where we are now, this is where the rover is.
These rock layers off a few kilometers in the distance are
what we are going to be driving to.
A rover on Mars is very slow.
It goes a hundred meters a day.
Now, you know, a sprinter covers that in 10 seconds.
They are continually computing their way through terrain,
using stereo cameras on either side of the mast
to take images, images, images, images,
collecting samples, as we go.
Occasionally, we are able to make discoveries that,
you know, are worth sharing, and it's like, really exciting.
The reality though, is that those discoveries are made
usually in fractions and often what's reported is
the product of a year or two of work.
The scientific community has been recommending
that we bring samples back from Mars for over 40 years.
And then the set of missions, starting
with the Perseverance rover to collect those samples,
later missions that will happen this decade,
to bring them back, were put in motion
by hundreds of people and decades of planning.
We have to be, you know, really patient
because planetary science missions take a lot
of resources, they take a lot of people,
they take many years to develop.
And then oftentimes, they take many years
to get to their destinations.
Even once they're launched and off the planet,
in the outer solar system, you know, transit times
to get there are seven to 12 years
and that's after you've launched, and, you know,
after you've already spent 10 years building the craft,
so, you know, thinking on that long-term time scale is
super important to me.
I'm driven to explore space because I like the exploration.
I'm curious, I want to know how planets work.
Other people are driven by just the sheer excitement,
they want to be a space tourist.
Or they're driven by profit; they wanna be
the first company to mine water on the moon
and use that water for rocket fuel.
So I think all of these ideas can coexist in space.
It doesn't sort of freak me out that this is happening.
It's the next transformation in our society.
It's going to the final frontier and that frontier,
right now, is in space.
But I think as the commercial side
of space exploration grows,
as the number of nations involved grows,
there is a real need, right now,
to really come to agreement as a species
about what the ground rule should be.
Because, you know, historically,
exploration has turned into exploitation.
I hope we've learned from that.
We wanna tread lightly.
We wanna understand the system and what we see,
the landscape, rather than destroying it.
I feel a sense of obligation and care as we explore
to protect those places that we visit.
By exploring these sister worlds, we really learn something
about how fragile the balance can be
between the climate of a planet
and the conditions that support life, or not.
I think if Mars once had life,
it probably still has life today,
but it will be very hard to find
because the surface, right now, is harsh.
Climate change happened on Mars.
Climate change also happened on Venus
where we have this hellish greenhouse atmosphere.
You know, one of the things that we're facing right now is
climate change on Earth, and it's not so much
that the climate is changing, Earth will be here.
The Earth's climate has changed many times.
But what's different now is the pace, the rate
at which the climate is changing.
It's changing at a rate that's faster
than most life can keep up, this teeming web
of this ecosystem of life that has evolved to be
in balance with the climate that we have now,
not this rapidly changing on the scale of decades.
So there's really a sense that I get
by thinking about long-time,
by thinking about natural pacing of change,
how really fragile it is that we've hit the balance
on Earth for life, and it's here right now,
and we don't wanna lose that.
One of the things I acutely appreciate
as a planetary scientist is how special our world really is.
Across all of the many bodies of our solar system,
across what we've been able to see, so far,
we know of exactly one planet that, for 4 billion years,
has had life on it.
Our planet has changed over those years
but it has been an abode of life in the universe,
and we're trying to figure out why.
So in looking outward into space, there's also a looking
back inward to what we need to do
to keep our planet and its web of life intact.