This is geology B with all of us Rumple.
So far, almost all the mapping of Mars has been performed using
data from spacecraft in orbit around Mars, while Imaging
instruments aboard, these craft can now obtain an impressive
resolution of 25 cm converting, the imagery into a geological
map requires ground-truthing. The data that is making the
connection between satellite image features and what they
correspond to on the surface. The most reliable way of doing
that is to identify an actual corresponding rock.
Sample on the ground on Earth. We can just organized a field
trip to the location in question, look at the Rock
closely. Perhaps using a hand lens and
take it back to a lab where we can bring to bear powerful
chemical analysis and dating techniques But on Mars, at least
so far, we need to land a robotic Rover.
Katie stack is Deputy project scientist for perseverance and
NASA rover that landed in j0. Crater on Mars in February 20 21
a geologist by training. She has been mapping the geology
of Mars since the 2000s. Katie stock.
Welcome to geology B. Thank you.
I'm so happy to be here today. It's hard enough.
Making a geological map of Earth.
But how do you go about making such a map of Mars?
There are some similarities and some differences.
But our main data sets instead of our eyes and walking around
in the field as we would do on Earth.
It's a photo geologic exercise. And so we use Orbiter images and
as you mentioned they're quite good.
Resolution 25 cm per pixel. And we use those images as well
as digital elevation models. Produced from stereo pairs of
those images to give us topography.
It's our job to try to take what we see with our eyes in those
photos of the surface of Mars drape it on top of and over the
Topography of Mars and try to determine what geologic units,
are present on the surface. Before we get to perseverance, I
can't resist asking a kind of broader.
Ideological question about Mars. We all know about the volcanoes
and in fact that Olympus Mons is probably the biggest volcano in
the solar system, but are there other mountain ranges on Mi
anything? Resembling the kind of orogenic
belts we have on Earth, not really?
And that's an interesting thing about Mars and what makes it
different from Earth in a lot of ways, as far as we understand,
it, Mars didn't have plate tectonics, so, Don't get the
creation of that kind of topography in those kinds of
mountain belts. But we did have structural
events occurring in Mars is history.
And so while we may not have those big mountain belts, we
have vast, Canyons Valles. Marineris is the best example,
the largest canyon system that we know of and the size of the
United States. Also, the other difference, we
have geologically on Mars is the role and preservation of impact
cratering impacts have so much shaped the surface of Mars and
what it looks like and we have images of these.
Soaring crater rims and the deposits that form within these
craters, let's get back to perseverance.
What instruments does it have that are relevant to the geology
on Mars? As we have a very exciting Suite
of Science in geology instruments on this Rover
perseverance, we think of, as a roving astrobiologist, it can
make those basic fundamental geological observations because
we have context cameras that can image the landscape from far
away. But also Very much up close.
And we have the next version of the Mars hand lens, imager.
That was, on the Curiosity Rover, we have a very similar
camera on perseverance. It's called Watson and that, of
course, assists in building geologic context, but we also
have the ability to view the surface of Mars with the
perseverance instrument payload in other parts of the
electromagnetic spectrum, different wavelengths.
And that's ranging, from the pixel instrument that uses
x-rays to study, the composition of the surface to are visible
and near-infrared. Infrared multispectral cameras
that can reveal more about the chemistry and mineralogy of the
surface. I should also mention if we're
talking about geology instruments, a brand new
instrument is the rim, facts, instrument, that uses
ground-penetrating radar to see into the subsurface and that's
an exciting new capability. Especially from a geology
perspective, as we look to build the stratigraphic context in
depositional context for the rocks that we see at the
surface, how far can you penetrate?
It depends on the Ariel, but up to 10 to 20 meters below the
surface. That's amazing.
Yep. When we spoke before, I think
you also mentioned a microphone. Yes, we have a microphone riding
along with the super cam instrument, which is an
instrument Suite on the master the road or the head of the
Rover. And we can turn that microphone
on to hear the sound of the super camel.
Laser basically a blading zapping the surface of Mars, and
we're using that sound. To better understand the
material properties of the rocks and materials that were zapping.
And we can also learn about the atmosphere, as well as the sound
travels through the air in the atmosphere to get from the
surface to Supercat microphone. And so we are able to engage
another sense for the first time on the surface of Mars.
We see and now we can hear on the surface.
So let me see if I understand this.
So you zap a rock with a laser, it then suffered some kind of a
explosion or something. You then pick up with a
microphone? Well, I would say it's not quite
as exciting perhaps as an explosion would make it sound,
but we use a technique called lid.
So laser-induced breakdown, spectroscopy, where we have the
super Kim instrument fires, the laser at the surface of Mars and
we essentially turn that rock or soil into a plasma and then we
have a spectrometer in the super cam instrument that analyzes
that plasma and looks at the composition of that plasma.
And that's how we figure out what elements are.
Are present in the rocks or soil is that we're studying but when
we do that zap when we do that ablation and turn the rock or
soil into the plasma, it makes a sound and we can hear that sound
with a super cat microphone. It's very early days till I
realize. But what have you seen so far
with these instruments? Yes.
Well we've seen rocks, lots of rocks and lots of sand and
that's as expected in Jezreel crater, which is the now home of
the perseverance for over the crater itself is home to a
Deposit that we think was formed when an ancient river entered
jezza, row, crater, and deposited, those sediments and
then we have the crater floor, which is where perseverance
landed and we talked a little bit about geologic mapping and
this is now one of the most mapped craters, any time we send
a mission to Mars, that area becomes the focus of many
geologic, mapping efforts. So we've thought for years about
what these Rock units represent. And there was a lot of debate
about the crater floor. Some folks thought it Might be
volcanic every time we see a heavily cratered surface on
Mars. Many folks think of Mars as a
volcanic basaltic planet. And so there's often an
assumption, that every cratered surface.
We see is an ancient lava flow, but more recently, especially
fed into by new observations, from the Curiosity, Rover, and
Gale Crater where we have exclusively almost exclusively
sedimentary rocks. We're learning that.
Maybe that distinction isn't quite as easy to make as we
might have thought it was. So other folks thought that the
crater floor could be sedimentary.
We are after all In an impact, crater with a Delta and an
ancient Lake. And so perhaps these rocks are
ancient Lake sediments and so we went into the landing of the
perseverance Rover. With this big question are these
rocks? Volcanic, are they sedimentary?
Or are they something else impact i'ts or something like
that. When we've landed, we found
rocks that appear to be relatively fine grained, but we
still are asking ourselves. Are they volcanic or are they
sedimentary? And we are still in the process
of getting our instruments. It's online and operational.
As we bring on some of our instruments that can see the
Rocks up close and personal. I think we'll make more advances
there on that question, but it is the big question and it's
one. We're still asking even though
we're on the surface right now, that is amazing.
That with all this incredible technology there, you haven't
been able to answer the most basic question about these
rocks. If you have the sample of this
rock in your hand here on Earth, How hard would it be for you to
identify it? Yeah, you know that's a great
question and almost isn't a fair question because we can bring to
bear when we as people and geologist and humans are looking
at a rock something, that's as simple as simply taking the
Rock, and turning it to get a different lighting condition or
changing our point of view on the rock or moving it closer to
our eyes or further away. Those are such simple things for
us to do. My guess is that if I was
holding this rock in my hand, I dunno.
Maybe give myself Couple minutes just to be sure but then I'd
probably have a pretty good sense but it really speaks to
the challenges. I think of doing, geology
remotely and every motion or every approach you take to a
rock, is something that you have to tell our robotic Explorer to
do and lighting isn't always favorable.
Sometimes you have shadows in the way and you have to work
around that and of course, the fine-grained rock, whether it's
a Basalt or a fine-grained siltstone or mudstone or fine.
Sandstone, you have to really think what The observations at
the limits of resolution that your instruments, allow you to
see that would allow you to distinguish one from the other
and also the bar has to be very high for confirming an
interpretation. So it's good to have healthy
skepticism. I think what we've seen over the
course of the eight and a half years that the Curiosity Rover
has been on the surface of Mars is that you have this
uncertainty in the beginning. You're in a brand new place
you've never seen these rocks before and we've only been to a
handful of places on Mars to begin with.
And so it takes a little while for To calibrate our eyes and
our expectations and build up that geologic context.
That feeds into making an observation of the origin of
Iraq. But once we get a couple miles
under the wheels, and we've been in at the Landing site for a
while. I'm going to guess that we'll
look back on these rocks and say, well, of course, they were
this and, you know, we just needed a little bit of time to
work through it. It's all part of the Natural,
Evolution of doing robotic, geology, and remote geology.
Yes. That time.
She brings me to my question is to what the overall geological
Objectives of the mission are yes.
Well, perseverance is the first step in a potential Mars sample,
return effort to bring samples from Mars, back to Earth.
The fundamental questions we have about Mars and its history.
And whether there was ever Life on Mars, really need to be
answered here, Labs on Earth and using the full set of analytical
capabilities that we have here. There's a limit to what you can
miniaturize and said to another planet and have it be robust
enough to work. It can take some very sensitive.
To determine whether something is indeed a bio Signature Sign
of ancient life and we see that in our own study of the ancient
earth rock record. It's quite contentious.
Sometimes whether we're looking at evidence for ancient life and
so perseverance is role is to collect the samples.
And so we have a sampling and caching system that allows us to
collect Rock and soil samples about 50 grams per sample tube.
We have 43 tubes that we carry with us, some of which are
controller, witness tubes, we call them, but we're aiming to
To collect about 30 geological samples.
And so, because perseverance has this role in Mars sample,
return. We are looking for a special
Suite of samples from Mars. That will help us address.
Whether there was ancient life on the surface of Mars at some
point in the past and to understand the evolution of the
planet. From a time when it was
habitable to the time where today it is no longer habitable,
we talk about the logistics of the mission.
How do you actually go about achieving?
Seeing these objectives. I guess you're planning from day
to day, week, to week month, to month, year to year.
We tackle it at different scales both spatially but also
temporarily. We've already started.
And before perseverance, even arrived on Mars.
We were thinking about our strategic long-term planning of
what the mission would look like.
And we started that using the orbital data and doing a lot of
the planetary geologic, mapping to understand what rock units
were present. And even just selecting The
Landing site. Where did we want to go?
What did we know about these places?
Based on our existing data sets. And so before we landed with
perseverance, we had already sketched out possible Traverse
options with the Rover. That would ensure that we would
visit all of the exciting geological units with high
potential for having signs of ancient life.
But then, of course, you get on the ground and you have a whole
new scale of data to deal with. And you can see the surface and
see the Rocks up close and that can change things.
And so you have to build in some Discovery and exploration margin
into your plan and then of course we didn't know where we
were going. Land.
And so that's kind of the long-term planning.
And so you're always thinking about, okay, well, where do we
want to get to and what kind of diversity, do we need to put
into the sample cash? And that certainly is, Keeps Us
motivated to keep moving with the mission.
But day-to-day, we pull up to a new location.
We survey the Rocks around us, depending on what our resource
allocation is we think a lot about power and time every day
when we plan for the Rover will plan science activities and so,
we'll decide which instruments do we want to use today in which
rock targets are Ting. And in which instrument
capabilities would answer the questions we have about the
rocks. And so, sometimes we're using a
super cam instrument that we've talks about.
Sometimes we're using, just the cameras sometimes will say,
well, this is really interesting.
We have to get the arm of the Rover out and use some of our up
close Imaging and spectroscopic capabilities, its Dynamic
day-to-day, but you always have to have in mind that higher
level plan, otherwise you can really go down the rabbit hole
at anyone outcrop and it's this balance of day-to-day.
This is month to month versus year to year, and we've got this
follow-on mission to collect the samples.
So, we're a little different from other missions in that
respect, where we have a ticking clock and we have to meet the
next mission that's coming. Can you give me an example of a
kind of opportunistic. Discovery activity that you
didn't know about an advance, but you just had to do.
Yes. Well I can give you an example
from the Curiosity Rover, this was a great example because we
landed right on top of it, when we arrived in Gale, crater with
the Curiosity. Ah, steer over.
We happen to land on conglomerates River deposits.
And we had no idea they were there in advance because they
were too small to see and resolve in the orbital data.
And so suddenly we realized that we had plopped ourselves right
on top of a major scientific discovery which was the first
confirmed River deposits observed by a Rover.
And so we had to work into our plan some additional time spent
studying these outcrops that we could do some paleo hydraulic
Relations to figure out the depth of the stream and how fast
it was flowing. And what implications that might
have for the climate of Mars. At the time, we have another
great example from curiosity where our main focus of that
mission is, and always has been the five kilometer High Mound of
sedimentary rock in the center of the crater.
But we realized when we landed that, if we went, the opposite
way away from the mound, we might have a chance to see some
potentially habitable Lake deposits.
So we took a risk and drove in the wrong direction.
First and it paid off, we found our habitable environment, we
found those Lake deposits and were able to check off some of
the major high level objectives of the mission by making kind of
a bold decision to go in the other direction and we have the
same thing for perseverance. We're currently deciding.
How do we get to the Delta? We have two main routes that are
in play right now and we're trying to figure out which way
we should go balancing efficiency with scientific
interest. Can the Rover negotiate all the
terrain. There was also kind of safety
considerations about how you get from A to B.
Yes, there are certainly safety considerations, but we have
capability on perseverance, that allows us to navigate terrain, I
think more efficiently than previous missions.
The Rover has an updated computer processor that allows
it to do auto navigation, so it can image the surface as it's
driving and basically process those images to pick Safe route
as it's driving along, and previous Rovers have had this
capability to Curiosity, has it? But with a slower computer, it
is very time-intensive to do this kind of Auto navigation.
But with perseverance, we can do that auto navigation, much more
efficiently. So we should be able to drive
upwards of 150 meters per day on.
Good terrain, whereas previous Rovers have average something
closer to maybe 30 to 50 meters per day.
What's the long-term destination?
You mentioned checking out the Dell take deposits.
How far away is that and where do you expect the Rover to wind
up, at the end of its Mission? We landed about two kilometers
from the main Delta deposit. Although, we have a couple of
what we think, are remnants of a formerly more extensive, Delta
deposit. So we might have the ability to
preview these Delta deposits before we get to the main
contiguous Delta. But of course, the Delta is one
of our main exploration Targets in jezzer, a crater As well as
some deposits around. The inner margin of the crater.
Essentially at what we think might have been the shoreline of
this ancient Lake jezza wrote that once existed here.
And so we're very excited to explore those marginal deposits.
What we call them. Our goal is to have it
completed. Our exploration of jezza row at
about the qualified lifetime of the Rover, which is about one
and a half Mars years or about three Earth years and to have
deposited a cache of samples on the surface.
But then after that, if the Over is healthy and doing well.
Then we have a decision. We can choose to stay in jezza,
row, and continue. Our exploration within the
crater, but we've also talked about venturing outside.
The crater. We often talk here on Earth
about source to sink since we landed in the crater.
We're probably doing the sink first but we might have the
opportunity to go explore the source of these sediments.
That were brought into the crater and that we've explored
in the Delta. And so that's a really exciting
to have the potential to see these rocks in place where they
were originally deposited. Inside the crater also outside
the crater. We have some very ancient
Martian crust, 3.92 4 billion years old and older that period
of the solar system is a part of solar system history, not.
Well preserved in rocks here on Earth because of the constant
recycling, of our own crust. I'm curious about that team
Logistics and how you operate. What is your responsibility as
Deputy project scientist? Yes.
So I have the great honor to be part of the Science Leadership
team lead. Being a team of about 450
scientists from around the world who participates on the
perseverance rover mission. And there are three of us up in
the project science box. We have our project scientist
and then two deputies of which I am one.
And so it's our job to lead the science team and to also advise
and consult with the engineers who are operating the Rover,
oftentimes we are consensus Builders and working to get
those 450. People on the same page to
operate a single robotic, Explorer is sometimes no small
feat. What's up typical day?
Like, for you at the moment? And I, you somehow tied to the
moths diurnal cycle. Yes, it's a tradition for Mars
Rover. Missions to be on what we call
Mars time in the early days of the mission.
The Mars day is about 40 minutes longer than the earth day.
And so sometimes that means that Earth and Mars time are pretty
well aligned. But other times we're completely
out of phase with Mars for the first 90 days or.
So of the mission, we have the scientists and engineers Living
on Mars time. I did a modified Mars time
because I have young kids here at home with me and young kids,
don't respect the Mars time schedule.
So I did my best putting in a full day and then staying up
later to help operate perseverance.
But fortunately, we are getting to a period of time where we are
now out of those overnight shifts.
At least for the west coast of the US where I am.
So we are transitioning back to Earth time with that.
Though comes a loss in efficiency and how you operate
the Rover because there are times now when We'll be
sleeping, but the Rover could be awake doing things and we're
just not awake to program the Rover to do it but of course, it
comes with the advantage of giving us all a little bit of a
break. At what point will you have you
already pulled out your Suite of astrobiology experiments?
Yes, we haven't done it yet because those instruments are
still coming online, but we anticipate in probably about one
or two months, we'll have the full instrument Suite, ready to
go. And we're very excited to pull
out our astrobiology instruments for the first time and, and to
do that, really detailed mapping of the surface of these rocks,
to look for these combined signals of Elemental.
Position mineralogy morphological texture that we
can see as well as distribution of Organics and by putting all
of those things together that's how we hope to make a case for a
possible biosignature. Far and Away.
The biggest prize of this Mission would be to find a bio
signature on Mars. Can you speculate as to what
combination of discoveries with the instruments on perseverance?
If we are so lucky as to find a bio signature, is likely to at
least initially clinched the issue?
Yes, that's a great question. And, you know, what would a bio
signature look like on Mars? And what are you looking for and
based on our previous exploration?
With other Rovers and Landers on Mars and based, on our
understanding of how Mars has evolved over time, we're not
necessarily expecting to find evidence of ancient complex,
life forms on Mars will joke about the proverbial dinosaur
bone. But based on our understanding
of how Mars evolved our expectations are that if there
was once Life on Mars, it probably did not progress past
the microbial stage. And so we're looking for
evidence in the rocks of past microbial Life on Mars and we
have some great analogs for that here in the early Earth Rock
record. One thing that we point to often
is if texture called stromatolites and those are
fossilized microbial mats and they form.
When growing Matt interact with the sediment and are competing
with sediment to reach the light and get to the water here on
Earth, we see in the Rock record.
They form all kinds of interesting, morphologies and
conical shapes and Mound shapes. They're the kind of feature that
when you find them in the field, you look at them and think,
well, that's odd doesn't seem like physics.
We're just naturally. Really form these weird shapes.
But again on Mars, we have to have a really high bar for what
could be formed biologically or abiotic Lee and work is shown
here that you can even get stromatolite like shapes without
having life presents. That's always a tricky thing.
But that's exactly what we're looking for.
We're looking for these interesting Textures in the rock
that make us pause and scratch our heads and think, well, you
know, how would you have formed this without life without
microbial metabolism, and then combining those textures?
Hours with the geochemical and mineralogical side.
Knowing that when life is present and preserved in rocks,
you'll often see evidence of that microbial metabolism.
You'll see the elements and the minerals that life likes to use
and preserve concentrated in ways that would be unexpected,
if life wasn't present and good examples of that are
concentrations of silica find silica laminae or iron
concentrations are certain minerals that life might be
taking advantage of and then of course we have the Sherlock in I
meant that can detect and map the distribution of Organics and
so we'd be looking for concentrations of organic
molecules perhaps in these laminae.
Suggesting that it's not just a random distribution of organic
molecules that may be raining down onto the surface of Mars.
But we're seeing concentrations of Organics suggested of perhaps
past microbial life or microbial mats even growing there.
So off to a potential bio signature, what would you regard
as the most significant finding that the Rover might be able to
make where it is? Now, one of the things is to
learn more about this ancient Lake that we find ourselves in
understanding the evolution of that system and interaction of
the rivers coming into jezzer, crater in the history of water
in this crater and how that system evolved in its
habitability, its composition How long it was there?
I think we can make progress on that and learning more about
this Delta and using it as a representative of other ancient
Crater Lakes that we know are present on the surface of Mars.
One of the exciting things about j0 Crater compared to other
places on Mars is the presence of carbonates carbonate,
minerals that we've seen from orbit.
There's been a long-standing question about the evolution of
the atmosphere of Mars. We think that Mars once had a
thicker atmosphere in the atmosphere today on Mars is
mostly CO2. But then there's been this
question of well, if Mars had a thicker atmosphere, where did
all that CO2 go and what idea is that it could have been taken up
into carbonate minerals but carbonates are relatively rare
on the surface of Mars. And so just zero is one of those
places that we have confirmed carbonate deposits.
And so I think by studying those deposits in jezzer, oh, we have
an opportunity to make some great progress in understanding
the evolution of the atmosphere and surface environments on
Mars. If you could design your ideal
Rover for the next Martian, exploration Mission, what would
it look like? And where would you send it?
Oh, this is great question. It's kind of like picking your
favorite child or something like that because there are so many
great places on Mars to explore one thing that I think would be.
So valuable for a Mars rover, mission is to have absolute age
dating capabilities with the Rover.
I mean, that's one of the things that we are most looking forward
to with Mars sample. Return.
And because while we have constructed a relative geologic
history for Mars, we're missing the absolute time scale.
And we have to rely on the geologic relationships of, we
think we see this unit on top of that one, but we don't know how
old they are. And so being able to put
absolute age dates on the rocks that we explore in statue on the
surface of Mars, I think would be a great Advance.
Then I think the question would be, where would I send it?
I tend to, like, the sedimentary rocks on Mars.
That's what I study and what I'm most interested in one of the
places Cases that I'm very intrigued about is Valles
marineris, which is this big canyon system.
What's really neat about Valles marineris?
Is that you have been one place this combination of major
tectonic structural events occurring on Mars coupled with
sedimentary processes. We have deposits within Valles
marineris that we think are probably sedimentary.
We have sub lacustrine fans and we also think there is evidence
for volcanic deposits there and so you have in this canyon
system kind of like studies of Grand Canyon here.
And in the western us, the chance to see a fast record of
geologic history in one place. But while also, studying the
Confluence of structural tectonic sedimentary and
Volcanic, and maybe even impact processes on the surface of
Mars. So I'm very intrigued by Valles
marineris. We've never sent robotic
Explorer to Valles marineris, so I might choose that place.
Katie stock, thank you very much.
All right. Well, thank you so much for
having me for more about geology, b, as well as pictures
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