(soft music)
- Planetary
Protection I sometimes equate
to the National Park rules.
When you go there you wanna
make sure you leave it
in the same condition
as when you found it.
- [Flight Controller] And lift-off
as the countdown to Mars continues.
- [Narrator] After a
successful launch from Florida,
NASA's new Perseverance Rover
is on its way to the red planet.
It's outfitted with cameras, lasers,
sensors, even a helicopter,
all tasked with decoding
the planet's secrets.
The centerpiece is a drilling system
designed to dig up samples of Martian dirt
and prep them for a second mission.
One that will return
them to Earth for study.
They're looking for hard evidence
that Mars once harbored life
and that raises a whole
new set of challenges.
It means knowing what life
might look like on Mars.
- Most samples that contain signs of life
may not be so obvious.
- [Narrator] Where to find
it, how to collect it.
- We actually drill to about
typically 70 millimeters down.
- [Narrator] And it means keeping life
from doing what it does
best: Popping up uninvited.
- It might be that very quickly
life just goes everywhere.
- Can you give us an overview
of the concept of Planetary Protection?
- For Planetary Protection,
when we're exploring places
like Mars and other bodies
that may harbor life,
we have to make sure
that we do it in a way
where we don't spread
Earth-based contamination
to that environment.
There's also a flip side to that
if one day we bring samples back,
we have to make sure we protect Earth
from those samples as well.
- [Narrator] Planetary
Protection is so important
because of the endgame
this mission is teeing up.
Mars Sample Return.
- The Mars Sample Return will include
the first ever rocket
launched from another planet.
- [Narrator] Most scientists agree
we're unlikely to identify microbial life
with any instruments
we can fit on a rover.
We have to bring the rocks to us.
That's why Perseverance's biggest mission
is collecting samples using
a complex drilling system,
robotic arms, and specially designed bits.
If all goes well,
Perseverance could fill up to
43 titanium sample tubes with dirt,
hermetically seal them
and store them for later.
- And it's sort of this
wide ranging capability
that makes it a little difficult, right?
In order for you to go
and drill into rocks
on another planet, you
build a fairly beefy drill
but I also have to design it
for really delicate operations.
And so, you know, where do you have to get
that nice balance in there, right?
So it's pretty fun.
- And why is it so important specifically
when it comes to the samples
that they have to be extra clean?
Why do we need to go through
all of these precautions?
- So in particular for Perseverance,
we have to make sure that the parts,
the tools that are acquiring the sample,
are extremely clean, actually sterile.
Because when we collect that sample
we have to make sure when we open it up
and we interrogate it for
possible ancient microbial life
that we don't say, "Hey, big news flash.
"We found life on Mars."
And come to find out
it's actually something
that hitched a ride from Earth.
- Tell me about all the
precautions that you had to do
with the sampling system.
- Yeah, so we have taken
several precautions,
even to the design of the tubes
that will hold the Martian samples.
We designed it in a way
so that it would not be
recontaminated after we clean it.
We also expose it to a really
high temperature process
of 150 degrees Celsius
for 24 hours minimum.
- [Narrator] They also
swabbed it all over,
looking for microbial hitchhikers.
- DNA is a really good way to understand
what is on the surface of the spacecraft
without having to grow
it up on a Petrie dish.
No matter what is there,
as long as the signal is high
enough, you can detect it.
And we are using that list to
have kind of a passenger list
of things that could potentially
be on the spacecraft surface.
- Now one thing I've learned about
when it comes to Planetary Protection
and sending spacecraft to other worlds
is that the microbes
on Earth are resilient.
- Yes.
- So are there,
is there still going to be
some kind of living organisms
on this vehicle that we just can't help
and they're just gonna hitch a ride
no matter what we do?
- The golden standard that we use for like
this is the worst case
thing that we would find
on the spacecraft,
we use what we call bacterial endospores.
So these are microbes that can
go into a dormant-like state
and survive for millions of years.
So we target these because
it is the golden standard
of the hardest thing
on Earth to get rid of.
But that knowledge changes over time.
We thought it was a
different microbe in the past
and now we found something even hardier.
So yes, life here on Earth is resilient
and we're consistently,
continuously looking for
something else that'll
challenge our threshold
of what that is.
- [Narrator] All these
procedures will help to ensure
that when we get the
samples back to Earth,
they'll be as purely Martian as possible.
That way the hunt for
ancient life can begin.
Scientists will be
looking for biosignatures.
Materials they think might
have come from past life.
For Perseverance, that
means looking for minerals
and rock formations that are associated
with microbes here on Earth.
- Geologists often use the word texture
for shape in a rock.
Lifelike textures together
with lifelike compositions.
So that's chemical compositions,
you know, in the elements
that are important to life on Earth,
organic matter obviously,
the molecules that are important to life,
but also the minerals that
are important to life.
- [Narrator] It also means
digging up rocks and materials
that are really good at
preserving fossilized bacteria
on our planet.
- It can be rocks that contain, say,
a lot of silica, something
that is similar to
what occurs in modern day,
say, Yellowstone National Park.
Silica's just a very good material.
It has very, very fine grains.
So tiny they're smaller
than a microbial cell
and so silica is really good
at preserving the shapes
of microbial cells.
- Let's say that Mars was
abundant in microbial life
back in the day.
Do you think that's something
that we'll be able to
see in these samples?
- So life is everywhere on Earth.
Everywhere we drill into rocks,
as deep as we have ever drilled.
When you bring rocks out there
are cracks in those rocks
where there's water in the cracks
and you find microbes there.
So it might be that when
life emerges on a planet,
if there are widely distributed
habitable environments,
it might be that very quickly
life just goes everywhere.
You know, it finds a way like
"Jurassic Park," you know?
Or it could be that the conditions on Mars
were always much harsher
than they ever were on Earth
and that life could've gained a foothold
but only just barely, you know?
And it could've been
very patchily distributed
around the surface of Mars.
We really don't know.
- [Narrator] Perseverance's
destination is Jezero Crater,
NASA's best guess for a spot
that was once full of life.
It's a massive barren basin
but billions of years ago
it was a flowing river delta
that fed into a lake.
- If there were microbes in that lake
they had every opportunity to colonize,
especially, say, the edge of the lake
where you often find pond scum on Earth
where those sediments in a lake interact
with the gooey microbial
stuff and form these,
ultimately, these layered rock types
that we call stromatolites.
Basically, fossilized pond scum.
They can easily survive
for billions of years.
That's like our Holy Grail.
- [Narrator] Perseverance is just
the first step in this project.
Europe is leading the charge
on a follow up mission.
It would send another spacecraft to Mars
to scoop up these samples,
blast them off the surface,
and return them to Earth.
That will be when the flip side
of Planetary Protection kicks in.
Scientists will also need to check
for any live Martian
organisms that hitched a ride,
however unlikely that may be.
All of the Martian hardware
will have to be contained in some way
from the moment it touches down on Earth.
- Ultimately, it's very tightly sealed up
in an Earth entry capsule that's designed
to really actually hit
the surface of Earth
without even a parachute
so that we can be absolutely confident
that even without a parachute
it wouldn't break open
and inadvertently release
any of that stuff.
- [Narrator] It's a
process that could take up
much of the next decade.
But it's already given
Planetary Protection experts
plenty to think about.
- I feel like this is just
kind of the ultimate test
of Planetary Protection, right?
'Cause you're going forward
and you're coming back.
So what does it feel like
to be a part of this mission
as a Planetary Protection expert
and getting to test out
basically every rule there is
when it comes to this concept?
- We're really breaking new ground
with this Mars Sample Return campaign.
And I feel so small, in a good way, right,
in the context of this large mission.
It's kind of like there are a lot of jobs
that are somewhat thankless
and if I do my job right, you
won't hear about me, right?
I don't wanna hear, "Planetary
Protection did a poor job
"and we found life that hitched a ride."
No, when you don't hear about me,
then I know it was a success.
So yeah, I'd be happy for
the lack of praise (laughs).
