In 2013 CASW established a new
tradition for the New Horizons in
Science briefings: the Patrusky Lecture.
This annual lecture honors Ben Patrusky,
who served as CASW's executive director
for 25 years and as program director for
New Horizons for 30 years.
The Patrusky Lecture is meant to
provide a big-picture view of a broad
scientific field and the scientific
enterprise itself.
This year's lecturer, planetary scientist
Steve Squyres,
fits that purpose perfectly. But for me
there's also a personal connection. I'm
sure Steve doesn't remember this, but I
met him more than 20 years ago during a
AAAS meeting in Seattle when he
gave a talk about Europa, a mysterious
ice-covered moon of Jupiter. It was the
first AAAS meeting I ever attended
as a science journalist--and by the way, I
looked up the title of the session on
ArXiv.org, and the subject is just as
provocative today as it was back in 1997:
"Could Europa harbor submarine
hydrothermal life?" Since then I've
covered Steve's work primarily in his
capacity as principal investigator for
the science payload on the Mars
Exploration Rovers, which bounced to the
surface of the Red Planet back in 2004.
Those rovers were designed to last 90
days, but thanks to Steve and the other
members of the rover team, they kept
going for years longer. This February,
after 15 years of discovery, Steve and
his colleagues finally bid farewell to
the Opportunity rover on Mars. During a
career that has spanned more than three
decades at NASA, Cornell University, and
other institutions, Steve worked on other
space missions as well, including Voyager,
Magellan, the Near Shoemaker mission,
Cassini, Mars Express, Mars Reconnaissance
Orbiter, Mars Odyssey, and the Curiosity
rover. Steve led the most recent National
Research Council planetary decadal
survey and has served as chairman of the
NASA Advisory Council. He's a Fellow of
the American Academy of Arts and
Sciences, and last month he left Cornell
to move up to my neck of the woods in the
Seattle area. He's just beginning a job
as chief scientist at Blue Origin, the
space venture founded by Amazon CEO Jeff
Bezos. During today's talk Steve will
look back at the Spirit and Opportunity
missions on Mars, and he'll also look
ahead to the future of planetary
exploration. If he doesn't mention the
moon and Europa, I'm definitely going to
ask him about it during the Q&A. But
first we need to go through one of the
traditions associated with the Patrusky
lecture--the award of a certificate and a
Patrusky prism to mark the occasion.
Steve, I hope you'll accept these tokens
of our esteem and perhaps display them
in your new office at Blue Origin.
All right. So let me get the legal stuff out of the way first. I'm not here representing my current employer.
I'm just here as Steve the Mars Rover guy. And I'm gonna talk today actually not about the moon or Europa, sorry.
I'm sorry it's gonna be all
Mars, but you know, when we get to the
questions let 'er rip. It's a very
exciting time in the space exploration
business. For the first time in many
years we are talking in a serious
meaningful way about sending humans once
again beyond low-earth orbit and doing
it this time
to stay. And there's talk of humans to
the moon, there's talk of humans to
asteroids, there's talk of humans to Mars.
What I'm going to try to do in my talk
today is offer you my opinions--and they
will be just that, my opinions--on the
issue of sending humans to Mars. And I
will base those opinions
almost entirely on personal experience,
most of it having to do with operating
some vehicles on Mars for 15 years, and
also a few other things that I've done.
With my time at the end I'll tell you
what I think, and you may agree. You may
disagree. So this is Mars, the object of
our affections. It's a pretty tough
place to do business. The annual average
temperature is about 60 degrees below
zero Celsius. It goes down to minus 100
Celsius at night. If you took all the
water vapor in the Martian atmosphere
and you condensed it out on the planet's
surface, you would make a layer of frost
that is barely a hundredth of a
millimeter thick. So it is today and for
most of its history has been a cold and
dry and desolate world. Now, as we think
about sending humans to Mars, the first
thing to recognize is that the idea of
sending humans to Mars has had an enormous
hold on the human consciousness for a
very long time. This is from the
wonderful movie The Martian. People have
been talking about sending people to Mars for a very long
time. It's a romantic notion, it's an
appealing notion, and the literature of
science fiction is full of stories of
humans going to Mars to explore, humans
going to Mars to stay. Now I'm gonna
suggest that there's sort of three ways--
these are not the only ways, but there
are three useful ways--of looking at how
humans might go to Mars at some point in
the foreseeable future. And I'm not gonna
try to look out millennia into the
future, I'm not going to try to go
multiple centuries in the future. So
we'll have our horizon be oh, a
century or two, okay?
Beyond that, my crystal ball is too cloudy.
One model is a research base. What
you see here is Amundsen-Scott Station.
This is at the South Pole of the Earth.
Very tough place to live,
yet there's a permanent research base
there, and people go there, and they do
meaningful scientific research. I've been
to Antarctica four times myself. I have not
been at the South Pole, but there are
these research bases in multiple
locations on the Antarctic continent. So
one way that one can envision
going to Mars is setting up a research
base where people, go do their work, and
then come back home.
Another is tourism. If you are wealthy
enough to afford it, you can buy a berth
on a cruise ship, and you can sail to
Antarctica. And many people have done
that, and you get to visit the continent,
experience it, admire its beauty, and then
again you go back home. So space tourism
focused on Mars is another possible
model of how this might work. A third is true
colonization. People go there to live.
They live their entire lives. They live,
they die, generations are born, you raise
babies on Mars. This is a place--one of my
favorite places on earth is this place
called Longyearbyen. This is the capital, if you will, of the archipelago of
Svalbard. Svalbard is north of Norway.
It's about 600 nautical miles from the
North Pole, and there's a town, Longyearbyen, I think it's about 2,000 people.
You know, there are banks, there's an
elementary school, there's a swimming
pool. People live there, they raise
their children, and one can imagine even
a fairly robust setting actually going
there and people going to Mars to live.
So those are the three possibilities
that I'm going to consider. Now I'm going
to spend some time telling you about
Mars, and we'll come back at the end, and
I'll tell you which ones I think might
work. So this is a picture--this was taken
at Cape Canaveral a long time ago now--
this was taken in 2003, shortly before we
launched the Mars Exploration Rovers off
to Mars. You can see the rover Spirit in
the foreground
all tricked out and ready to go to Mars.
If you look in the background, you can
see the Opportunity rover against the
far wall. I'm the good-looking guy in the
white
suit. These vehicles were our
surrogates. We built them to have as
human-like qualities as we could give
them, and then we experienced Mars
through their sensors. The spacecraft
that we built to get the rovers to Mars
is like one of those Russian doll sets,
where there's a doll inside a doll
inside a doll. You can see the rover at
the far right, and what it does is it
folds up in this horrifyingly
intricate fashion to fit inside a lander.
The lander structure you can see at the
lower right. Three colorful things on the
sides of that in that illustration? We
call those petals because they're like
the petals of a flower. And those petals
fold up around the rover, encasing it,
protecting it for the long trip to Mars.
And when it's all folded up you
can see sort of in the middle there it
forms a tetrahedral pyramid. Now that is
then encased in turn in another shell.
The front part of it is shown at the bottom
there. That's the heat shield that
protects the vehicle during the
high-speed descent through the Martian
atmosphere. There's a cone-shaped thing
on the back of that that's called the
back shell, and so that's another shell
that protects the vehicle. And that, the
kind of blue frisbee-looking deal on the
top of it, that we call the cruise stage.
The cruise stage provided
electrical power propulsion, the stuff
you need to get you to Mars.Trip took
about seven months. This is a complicated
plot, but it makes a simple point, and
that is you cannot depart from Mars
whenever you want. Not with the
propulsion systems that we have today
nor those that we're likely to have any
time soon. You have to wait for the
planets to properly align. In the case of
our mission, and in the case of most
future missions, the period of time
between launch windows is 26 months, and
if you missed that 26-month launch
window, you
don't get to go again until 26 months.
And in our case we had
hit that window in the summer of 2003, or
we were not gonna go to Mars
at all. We were spending a million
dollars a day. Nobody was going to keep
us going for 26 months if we didn't
launch then, our rovers we're not gonna
go to Mars. They were gonna go to the Air
and Space Museum--and not out on the
floor with the good stuff, down in the
basement with the stuff that never flew.
You can't argue with Isaac Newton. When
you get to Mars you're at the top of the
Martian atmosphere going Mach 27--
27 times the speed of sound. That heat
shield bleeds off kinetic energy. And
once the vehicle has reached a nice
leisurely Mach 2, we throw out a
supersonic parachute. You can see that at the
upper right. We learned the hard way that
supersonic parachutes are very difficult
things to design and build. The lander
descends on a long cord, and you can see
if the lower right what the vehicle
looks like as it's still screaming down
towards the Martian surface at about 200
kilometers an hour.
You don't drift down lazily on a
parachute on Mars. The atmosphere is very,
very thin. It's a really hard place to land.
We had a terrible time with our
parachutes. These are some pictures from
the tests that we did, the first test
that we did of the parachute design that
we thought was going to land us on Mars.
We did this test at a National Guard
gunnery range outside of Boise, Idaho. It's
a kind of place where you can drop big
heavy things from the sky, and they won't
kill anybody. We dropped our test article
from a Chinook helicopter at 4,000 feet. It
fell, deployed the parachute. It made this
perfect orange and white bowl, and then
it just exploded. It ripped to ribbons.
And parachute after parachute failed.
What we realized was that as our
understanding of the design of the
vehicle that we had to land matured, our
estimate of its mass grew. And by the
time we did this test, the vehicle was
too heavy for the parachute to function
properly. We embarked on a crash program
of parachute
redesign. We designed three parachutes in
parallel, praying that one of them would
work. One of them did.This is a picture
of a test of the parachute design that
actually landed us on Mars. We had our
first successful parachute test eight
months before we had to be on top of the
rockets in Florida. It was terrifying. We
land using the airbags. As Alan mentioned,
they're like the air bags in your car,
but a lot more expensive. They inflate
explosively around the vehicle about ten
seconds before touchdown. About a
second of two before touchdown, you can
see at the upper right, rocket motors
fire, we cut the air bags free, they fall
to the surface, and they bounce. And they
bounce and they bounce and they bounce,
and they roll and they roll and they roll.
And they can bounce and roll as
much as kilometer before the vehicle
comes to rest. And at the lower right you
can see a an airbag engineer at JPL
being consumed by his work. We had a
terrible time with the airbags as well.
You can sort of tell by the picture at
the lower right they're not having a
good day.
This was the first test of the airbag
design. We did it in the world's largest
vacuum chamber in Sandusky, Ohio, taking
the bags and whacking them down on a
platform that was studded with sharp,
pointy rocks--and they burst, they ripped.
We had to redesign those.The only way to
solve that problem was to brute force it
by making the bags stronger, reinforcing
them adding more layers of fabric, which
made the whole system heavier, which made
the parachute problem worse. We got it to
work. On the left you see a picture from
one of our first successful parachute
tests, on the right the ultimate test.
Those are parachute, or airbag, rather,
bounce marks on the surface of Mars.
This is what the vehicle looked like when we
put it all together. This is a big
thermal vacuum chamber at JPL. We
launched in the summer of 2003--
two launches on Delta II launch vehicles,
one in the daytime, one at night. And as I
said, it took us seven months
to get to Mars. And we got there in
January of 2004. Landing was very tense.
One of the most memorable--two of the
most memorable--nights of my life. You can
see me at the lower right there with
hair there was a lot less gray than it
is right now. But when it works it feels really really good.
Let me tell you a
little bit about some of the science
that we did. I could talk for hours about
the scientific accomplishments of Spirit
and Opportunity. As Alan mentioned, they
were each designed to last for 90 days.
We got six useful years out of Spirit and
14 and a half useful years out of
Opportunity. So the scientific return
that we got from the vehicles was
immensely more than I could have
imagined in my wildest dreams, and I had
some pretty wild dreams. You can see here
the landing site for Spirit ,that great
big blue crater in the middle of this
image, the topographic map. It's called
Gusev crater. It's 160 kilometers in
diameter, 16 degrees South latitude on
Mars. The reason we chose it is, if you
look, to the south of that crater there's
a great big dry riverbed flowing into
the crater. Now, there's no water in that
river now--there hasn't been for billions
of years--but it was carved by water.
There has to have been a lake in Gusev
crater at some point in the distant past.
And so we went there searching for
layered sedimentary rocks laid down
billions of years ago on a Martian lake.
We did not find them. What we found was
that the crater was full of lava. Mars
faked us out! I'm still convinced that
those sediments have to be down there
somewhere, but they had been buried with lava.
Fortunately the rover lasted long enough
that we were able to drive it way
farther than its design distance to a
wonderful range of hills that we named
the Columbia Hills, after the Columbia
Space Shuttle. And we spent hundreds of
Martian days climbing to the top of the
highest summit in the range. We named it
Husband Hill, after
Rick Husband, who was the commander of
the Columbia when it went down. This is
the view from the summit of Husband Hill
looking to the south.And most of the
most important scientific discoveries
from Spirit's mission actually came after
we crested Husband Hill and went down
the other side. I'm just gonna tell you
about one of my favorites. It took
place right here in here a place that we
call home plate. About 800 sols--
that's a Martian day--about 800 Martian
days into Spirit's mission, the right
front wheel failed so it would no longer
turn. In order to drive the vehicle, we
then had to drive it backwards, dragging
the dead wheel through the soil. And a
rover that used to do 100 meters in a
day, a good day, was now five meters. But
there was a silver lining, and that was
that that dead wheel dug this marvelous
hundreds-of-meters-long trench through
the Martian soil. Pure serendipity--we
never would have done that on purpose--
but wonderful things would pop up in the
floor of the trench. We were driving one
time through a little valley, and at the
end of the drive the soil in the trench
popped up as white as bright snow. This
caught our attention. We went over and
looked at it with our spectrometers.
It was not snow at all, nothing of the sort.
This stuff was more than 90 percent
pure silica, SiO2. It's not quartz, it's
not crystalline; this is not beach sand.
This was opal, hydrated amorphous silica,
this was opal like the gemstone. This is
the stuff that you find in hot spring
environments on Earth.
This was telling us of a hydrothermal
system that once existed at this
location on Mars. So this was compelling
evidence that in this little valley that
had these silica deposits, long ago there
had once been a habitable environment.
Of course we named the place Silica Valley.
Many more discoveries from Spirit which
I don't have time to tell you about.
Let me go to Opportunity.
This shows Opportunity's landing site.
We chose the landing site for Opportunity
not because of the topography--no hole on
the ground, no dry riverbed. We chose it
because of its composition. The image at
the upper right is from an infrared
spectrometer in orbit. And it shows the
occurrence--in the upper right there, the
red, yellow and green--of a mineral called
hematite. Hematite's an iron oxide. It's a
mineral that's present in rust, and it
usually forms as a result of the
action of liquid water. So this was like
a chemical beacon, visible from space,
saying "Hey! Water may have been here. Come
land here." Now, at the lower left you can
see an image of the topography:
wonderfully smooth, wonderfully flat, safe
for landing, safe for driving. It's a
terrific site from a safety perspective.
The thing that made me nervous about
this landing site was I was
concerned that it was so smooth and flat
that nowhere would we find the
topography necessary to expose bedrock
to our instruments. I need not have
worried. These are some of my favorite
images from the entire mission. As our
vehicle was descending towards the
surface. it had on its underside a camera
mounted that was looking down. And it had
just enough time to snap off three
pictures on the way down. You can see
those three pictures at the upper left.
If you look at the far right of that
image there's a crater, and just to the
left of it you see a little black dot.
The black dot's the shadow of the
parachute, okay? And then the picture
at the bottom just shows the same view
illustrated obliquely. Now, the red curve
is the reconstructed trajectory that our
vehicle went through as it went through
the landing process. So we're coming in
from the left. We're coming screaming in
from space, 200 kilometers an hour. We get
close to the surface. We fire the rocket
motors, drop the air bags
to the surface, and they begin to bounce.
The wind that day was blowing from the
south. So the trajectory bends to the
left--bounce bounce bounce bounce bounce
bounce bounce--and then, reading the green
perfectly, it curves gently to the left
and goes right into a little 20 meter-
diameter impact crater. Tiger Woods, on
the best day he ever had, could not have
pulled this off. No, this was just
pure dumb luck. We opened our eyes, and
there was a magnificent outcrop of layered
bedrock right in front of the rover. And
over the period about 60 Martian days,
just staying initially in this tiny
little crater, we made a series of
extraordinary, extraordinary discoveries.
I'll just tell you one of my favorites.
When we first drove off the land and we
looked down at the soil, looked at it
with our microscope, we saw that it was
littered with an uncountable number of
little round things. They were four or
five or six millimeters in diameter, and
they were absolutely everywhere.
Initially we had no clue what we were
dealing with. We drove over to the outcrop.
What we discovered is that the little
round things were embedded in the
outcrop like blueberries in a muffin. A
muffin is soft, the blueberries are hard,
the muffin would erode away, and the
blueberries would fall out. And they're
absolutely everywhere. This is a picture
taken with our microscopic imager, a
couple centimeters across, and you can
see the little hard blueberry embedded
in the layered muffin rock. After
studying these extensively, what we came
to realize was the blueberries--which are
made of hematite; that's where the
hematite signature comes from, is those
blueberries--the blueberries are what
geologists call concretions. Concretions
form typically in sedimentary rocks
on Earth that are saturated with liquid
water.
There is some mineral, like haematite,
that is dissolved in the water.
It is supersaturated; it wants to
precipitate out. It finds a nucleation
point. This starts to precipitate, and
then you create a concentration gradient
so stuff diffuses down that gradient, and
it adds layer upon layer upon laye,
building a little hard, spherical nodule
in the rock, like the way an oyster
builds a pearl. So this was compelling
evidence at this place that liquid water
had again once been present. So many
scientific discoveries by Opportunity
that I would love to tell you about.
Don't really have the time to do that in
this format. I'll do one more for you.
Late in Opportunity's mission we drove
to a very large crater--22, 23
kilometers in diameter--that we named
Endeavour. And as we pulled onto the rim
of Endeavour Crater we saw this, multiple
places on the ground. It looked like
somebody had taken a can of white paint
a paintbrush and had painted white
stripes on the ground--nice, straight
white lines. We went and looked at them,
and what we found was these were veins
of some kind of mineral. When we measured
its composition. what we found was this
was essentially pure gypsum--calcium
sulfate. Calcium sulfate salt gets
precipitated from liquid water. So this
is a place where there were fractures in
the rock, and at one point 
billions of years ago in the past, liquid
water flowed through those fractures and
precipitated out these gypsum veins. So
again compelling evidence of the action
of liquid water at the surface of Mars.
Now there were many wonderful scientific
discoveries, but I don't want to give you
the impression that we had an easy time
of it. We had a very hard time of it. Mars
is a tough place to do business, and I'm
gonna try to give you a little bit of a
a sense of that. It's a
hard place to drive around.
In order to get to Endeavour Crater,
Opportunity had to do a 20-kilometer,
20-plus kilometer drive, and that involved
at one point during the mission driving
through a little dune field. Now
initially, as we left our very smooth
landing site and worked our way into
this dune field, we were doing great.
We would go over one dune and over
another and over another. We were
basically trying to set records for how
far we could drive in a day. I think our
all-time record was like 204 meters in
one Martian day. We were using a mobility
technique that I will describe
generously as bombing along at top speed
with our eyes closed. And it bit us. As we
got farther south, these little dunes got
bigger and bigger. And one terrible day,
we hit one. And I still don't completely
understand this, but we hit one that was
just a little bit different from all the
others. And the wheels broke through a
crust, and we did 50 meters worth of
wheel turns, thinking that we were
driving happily across the plains, and in
fact we were just digging ourselves
deeper and deeper and deeper into the
soil. We came in the next morning, and all
six wheels were buried over the hubcaps.
This was a bad day.
Now the first rule in a situation like
this is: don't do anything stupid that's
going to make the problem worse.
Okay, the sun is shining, we've got plenty
of power, the robot's obviously not going
anywhere.
We've got time to work this out. When we
built the rovers, we actually built four
of them. Two of them, Spirit and
Opportunity, went to Mars, but there were two
more back on Earth that we'd use to
simulate predicaments that we got
ourselves into and then try to work our
way out of them. This is one of those two
rovers. This was just very recently
shipped to the Air and Space Museum,
where it's going to go on display soon.
In order to simulate this particular
predicament,
we needed a very large quantity of fake
Martian soil. iIf you ever called upon to
create fake Martian soil, here's the
recipe I recommend that you use. It's
equal parts play sand--the stuff in kids'
sandboxes--clay, and diatomaceous earth,
the stuff that's used in swimming pool
filters. Once we worked out this recipe, a
bunch of engineers in pickup trucks
fanned out across the LA basin and
brought up literally tons of these three
ingredients. People were getting algae in
their swimming pools all summer long
because of us. We brought it back to JPL,
mixed it up, drove the rover into it, and
then we spent two and a half weeks
rehearsing--trying to figure out the
optimal way of extracting a robot from a
sand dune on another planet. A lot of
things you can do. You can run the wheels
different velocities, you can rock the
vehicle, okay? You can steer the wheels
back and forth to try to open up the
holes that they're in a little bit.
We tried all of those and many others, and after
two and a half weeks we found the
optimal technique. The optimal technique
was to put it in reverse and gun it.
There's no place you go to look this
stuff up, okay? Anyway, here we are gunnin' it on Mars.
Time-lapse image here. We were in bad shape.
That's the left rear wheel. We had
to do 192 meters'
worth of wheel turns to get the rover to
move one meter.
But one wonderful Saturday morning, after six weeks stuck in a feature we later came to call
Purgatory Dune, the vehicle popped out.
And we treated those dunes with much
greater respect from that point forward.
Ah, dust. I guarantee you that when
the first astronauts come back from Mars
and people say what was it like?, one of
the first things they will say will be, "I
hated the dust." This stuff is everywhere.
Now I told you at the beginning I liked
the movie The Martian, and I did. But that
storm at the beginning, with the gravel
flying around? No., Mars does not do that.
When you think about dust on Mars, don't
think about gravel. Don't think about
sand. Think about cigarette smoke, micron-size, particles cigarette smoke. So I
loved that movie. I thought, the storm at
the beginning ? They could have found a
better way to strand Matt Damon on Mars,
okay? Other than that, good movie. But that
dust gets everywhere, and even though
the Martian atmosphere is so thin, it is
capable of suspending dust. And then that
dust settles out, and it coats everything.
This is a rover selfie. This is a picture
that Spirit took, I guess, about 250 days
into the mission. Now when the rover was
brand new,
straight off the showroom floor, clean
solar arrays, full sunlight on the arrays,
the solar arrays would put out about 900
watt-hours of power per Martian day--
enough energy, 900 watt-hours, to run a
100-watt light bulb for nine hours.
As the dust accumulated, that energy
output went down down down down and down,
and at the time this picture was taken,
they had dropped from 900 watt-hours down to
about 250. And death is somewhere around 150.
So Spirit was close to the end. And then
one wonderful day, this happened.
Lucky gust of wind overnight hit the
vehicle, and the power overnight went
back up to 850 watt-hours. Pure dumb luck.
It was as if this had happened. What
actually happened may have been more
like this.These are dust devils, little
Martian mini-tornadoes. You can almost
see Dorothy and Toto flying through the scene here. But we may have
been hit by one of those that kind of
vacuumed the dust off the solar arrays.
But that dust is a serious problem. The
dust accumulates and then is sometimes
removed in a pretty repeatable way over
the course of the year. This is
something that we call dust factor. It shows you how much dust there is on the
arrays. With a dust factor of one,
that's a perfectly clean array. Dust
factor of zero means that no sunlight
gets through at all. And this is dust
factor as a function of time. And what
you have at the bottom is the
Martian year--winter, spring, summer, fall--
and you can see it is fairly repeatable
from year to year. So there are some
periods in which dust accumulates and
other periods in which dust gets taken
away. But it is constantly in motion and
is a constant issue on the planet. Then
Mars from time to time experiences
global dust storms.These global dust
storms when they occur, they occur
during the Southern Hemisphere summer.
That's when the maximum heating of the
surface by the sun takes place. That's
when you get the maximum energy input
into the atmosphere. Stirs up the winds and gets the
dust going. And in a matter
of just weeks, you can go from a really
nice view of the planet as seen from
space to everything essentially
completely obscured. It doesn't happen
every year. We experienced--over the
course of 15 Earth years--on the surface
of Mars we experienced two global dust
storms. The second one, just last year, was the one that put an end to the mission.
That was the one that killed Opportunity.
There was another one not too long after
we landed, and that caused us a lot of
trouble.
This is 1,200 Martian days into--let's
see, that must be Opportunity; yeah, that's
Opportunity's mission. You can see how
things looked. There's a parameter called
tau. It's a measure of the
atmospheric opacity. The higher it is, the
more opaque the atmosphere. You can see
it at left, normal conditions; at right,
getting into the depths of a pretty bad
dust storm. Now, if you were on the Martian
surface, standing there in your pressure
suit, and there was a wind howling,
blowing dust around, in that big stiff
suit you wouldn't even feel it.
You're not gonna tip over in the wind.
Nothing like that happens on Mars
because the dynamic pressure of that very
thin atmosphere, even at high velocities,
100-mile-an-hour wind, exerts very little
dynamic pressure on any surface. So again,
Matt Damon wouldn't have gotten blown
over in the wind. But the dust--the dust
gets everywhere. Again, it's semi
repeatable from year to year. This is
that atmospheric opacity measure. Low
is a clear atmosphere, high is an opaque
atmosphere. And you can see--this is
multiple Mars years--pretty repeatable
from year to year, especially in the
first half of the year. And then the
second half on this plot was 
getting into southern summer. You see that
some years there are these big spikes.
And those are the
dust storms. The first dust storm nearly
killed both rovers. The second one did
kill Opportunity. This is just a plot; the
main thing to look at is the blue curve.
And this is the solar array energy in
watt-hours. We start off the storm at
about 700, and then day by day it dropped
and dropped and dropped and dropped, and
it dropped down below 200. So this was
nearly a very, very bad experience for
the rovers.They survived this one.
Temperatures: Mars is brutally cold. There are
two bad things about the thermal
environment on Mars. One is that it gets
incredibly cold at night. This is the temperature of our solar array.
So this is a surface on the rover
that gets illuminated directly by the
sun. So this is warmer than the
atmospheric temperature in the daytime
because you've got direct sunlight on it, okay? You see in the daytime surface
temperatures can get as high as zero,
maybe 10, 20 degrees C. But look at the
nighttime temperatures: -100. And
this is near the equator. It is a
brutally cold place. The other thing to
note is the enormous differential
between daytime and nighttime: more than 100 degrees C. So everything you build
that gets exposed to the surface
environment expands-contracts, expands-
contracts, expands-contracts every 24
hours and 39 minutes, the length of
Martian day. So it's a very tough thermal
environment, but it is incredibly cold
at night. And the mean temperature, the
average temperature--the temperature that
things will equilibrate to if you build
a piece of hardware or a habitat
anything like that--the temperature it
will equilibrate to
without heat to keep it warm is -60 C. Minus 60.
There are seasons on Mars. The seasons are similar to those of Earth. They result from the obliquity,
the tilt of Mars's spin axis, being almost the same as on Earth. And we always thought, even if the dust
accumulating on the solar arrays didn't
kill us,
we were always convinced
that the first winter on Mars would kill us.
The reason for that is we were in the
southern hemisphere, and in the southern,
in the winter, the sun goes very low
in the northern sky. And so with that sun
low in the northern sky, we had no
capability of tilting our solar arrays
towards the sun.We couldn't articulate
them. And so you did the math, and it said
the rover's not going to survive, even with reasonably clean solar arrays.
So we always knew the first winter would be fatal.
We weren't thinking hard enough. We
designed these for landing sites that were
very smooth and flat. And so in all of our
calculations we assumed that the rover
was on flat ground. But what happened was we were able to cover so much ground
that by the time winter came, we could be
on hillsides--we could be in the
mountains. And I showed you earlier that
picture of our route up Husband Hill,
and if you looked at it carefully, you
will notice the wind just goes blasting
straight up the west ridge. We could have--it would have killed us, but we could have
done it. Instead we drove around onto the
south face--excuse me, around onto the
yeah, onto the south face. And what that
did is in the wintertime it tilted the
rover, pointing the solar arrays towards
the sun. The whole rover tilted. And so
what we would do when we were driving is
we would make maps. And this is one of
them here from the mission. We would make these maps that showed the angle of
sunward tilt of the terrain. We called
these lily pad maps.
And the places that have good sunward tilt
are the ones shown in red. And what we
would do is we would drive from one red spot to another to another like a frog
hopping from lily pad to lily pad on the
surface of a pond. And in each of those
spots the solar arrays were tilted
towards the sun, the power was good, and
we were able to survive. And we survived
multiple winters on Mars just using
this straightforward trick. Mars time.
The Martian day, as I said, is not 24
hours long. It's 24 hours and 39 minutes
long. You might think that being able to
sleep in an extra 39 minutes a
day is a good thing. It is not. Not if you
live on Earth. For the first four months
of the mission all of us who were
entrusted with the care and feeding of
the vehicles lived on Martian time.
They were solar-powered vehicles; they
didn't care if it was daytime or
nighttime in Pasadena. They only cared if
it was daytime or nighttime in their landing site. And what that meant
was that our schedules had to be--our
days were 24 hours and 39 minutes long.
So if our daily operations meeting
starting started at noon today, the next
day it's going to be at 12:39, and the
next day it's going to be at 1:18, and it
works around the clock and two and a half
weeks later you're getting up in the
middle of the night--thank God for grad
students--and we had to live on that schedule.
Moreover, we had two rovers on
the surface on opposite sides of the
planet. So I had to split my team in half,
some working on Spirit, some working
on Opportunity. So I got everybody
living on Mars time, but in two very
different Martian time zones. And if you
were out working on one rover and you
wanted to switch to the other, you would
get Martian jet lag. So it was a very
difficult experience for us in some
respects. Now the interesting thing,
though, was for most of the team, for most
of the science team,
most of the science team was living in Pasadena--away from their homes, away from their families.
We had found apartment complexes where we could get, you know, housekeeping service
on Mars time. We had food service on Mars time; we had blackout curtains on the
windows. And what we found was that
people who were able to live on that
schedule could pretty much cut the cord
with Earth entirely. And if you cut the
cord with Earth entirely and switch over
entirely to Mars, it's easy;
24:39 is close enough to
24 hours. It's fine, and you do actually
get to sleep in an extra 39 minutes
each day. Now in my case I had to be at a
lot of press briefings, and the press
briefings were 8 a.m. Pacific time
every morning. Earth time. We couldn't have Mars time press briefings. I wish I'd
been able to put all you guys through it.
But yeah, there were days when I would
have to work a full, you know, ten-hour
shift at work, go home, go to bed, set the
alarm to wake up in three and a half
hours, come in, do a press briefing, and go
back home to bed. If you can cut the cord with Earth, though,
Mars time is pretty straightforward for
the people on Mars. For the people back
on Earth who are interacting with them
and keeping their schedule, it's gonna be tough.
All right, slight diversion. I want
to talk about one-way light time and the
the separation between Earth and Mars,
and what that means for people living on
the surface. I had the very interesting
experience some years ago--how long has
it's been now, seven or eight years--of
being a crew member on a project that
NASA calls NEEMO. N-E-E-M-O, NASA Extreme Environment Mission Operations.
It's conducted by NASA at a habitat in about 60 feet of water off the south coast of
Florida near Key Largo, and it's used
primarily for training astronauts.
This is one of my favorite pictures from my
second NEEMO mission. That's me there
going like this on the extreme right.
It's a funny picture. NEEMO is very
complex technically, a lot of stuff going
on, submarines, a lot of divers in the
water--very dependent on what the
conditions are like. Most of the time
things aren't going just right. We had
this one beautiful day, perfect day, when
everything was working.The submarines
were in the water; they were working; good
communications, good visibility, no
current--it was just perfect. And so the
project manager said, "Okay, I want you
guys to pose for the picture that I'm
gonna use on the first slide of every
NEEMO presentation I ever give." We said,
"what do you want us to do?" He said, "I
don't know, just look badass."
So this is us trying to look badass. And
that's for real--we got photobombed by a
barracuda. That was not Photoshopped in.
What were we doing? My missions--I was on two of them--our objective was to figure
out how to do field geology on an
asteroid. Now, most of the asteroids that
can serve as useful resources in space,
most the Earth-approaching asteroids, are
tiny things. You don't realize that most
of them are very small. This is the
asteroid Itokawa. It was the one that was visited and a
sample returned by the Japanese Hayabusa mission. There it is; there's the
International Space Station for scale.
This is so small that it is a zero-gravity object for all intents and
purposes. Its surface close up looks like
that. You can see a little red 1-meter
scale bar down in the lower right corner.
So imagine having to do a spacewalk,
an EVA where you are working on the
surface of an asteroid like that in zero
gravity. Now we have lots of experience
with EVAs on a planetary surface--the Moon--
that has one-sixth gravity. We know how
to do that. We have lots of experience on
doing EVAs on the International Space
Station. But asteroids don't have
handrails. And so our job was to figure
out how to do what this sort of fanciful
illustration of somebody exploring one of
these asteroids looks like. And this poor
astronaut is going to take out a rock
hammer. He's going to whack that rock, and
he's gonna learn Newton's laws really
quickly.
Now, for many years the way that NASA has simulated long-duration spacewalks,
long-duration EVAs in microgravity, has
been using this marvelous facility
called the Neutral Buoyancy Laboratory
at Johnson Space Center. It's one of the
world's largest swimming pools, 40 feet
deep. Right now it's got the entire
International Space Station mocked up in
it. This is a crew that's rehearsing how
to do some servicing on the Hubble Space
Telescope. So this, you can use the
neutral buoyancy afforded to you by
being in the water to simulate
microgravity, and where we did it was at
this Aquarius habitat that NASA makes
use of off the coast of Florida. I was
very fortunate to be on two NEEMO crews.
My first NEEMO mission, NEEMO 15--you can see the crew at the top--we had a tough
mission. The conditions were not very
good for most of the mission, and then
five days in what was supposed to be a
two-week mission we had a hurricane,
Hurricane Rina, bearing down on us. And
topside they made the decision to
evacuate us from the habitat. So we had
to do an emergency evacuation from the
habitat. They pulled us out, and we didn't
get most of our job done. So I was
very fortunate. This NEEMO is used mostly for astronaut training
it's a very spacelike. But I got--I was like the one kid who got
held back in fifth grade and had to
repeat it, okay? That was me, and I got to
repeat NEEMO and do NEEMO 16, where we had great conditions and a very successful
mission. As I said, what we were trying to
do was simulate. For the most part, we
were focused on simulating operations at
an asteroid and trying to figure out how
to do that. And the technique--this shows,
this is me on the seafloor doing
an asteroid surface EVA--and the
technique that we found worked best was
this. When you have a small spacecraft,
the spacecraft has the ability to
position astronauts near the surface of
an asteroid. Your feet are clipped into a
to a platform; your hands are free.
Platforms like this have been used on
the International Space Station and the
Shuttle for many years. It's a great way
to get the job done. So that was the
primary finding. Now the other thing that
we did on these missions was--especially
NEEMO 16--we conducted the entire NEEMO 16
mission, with a couple of brief
exceptions, at a 50-second delay between
Earth and our habitat. So when we
communicated with the people topside,
with mission control, there's a 50-second
one-way delay. And that
number was chosen because it's typical
for an asteroid mission. This was the
first simulated mission ever done by
NASA that put in a time delay. And what
we found was that it rather dramatically
changed the communication situation.
Then, for part of NEEMO 16, we did it with a five-minute delay to simulate Mars.
Now this picture--this is from NEEMO 15. In NEEMO 15 we were using real-time
communications. We spent almost every day on NEEMO doing simulated EVAs. I spent most
of my time either outdoors or supporting
people who were working outdoors. But
there was one day in which we focused on
simulated emergency scenarios
They didn't tell us what they were going to
hit us with. They just said be ready.
So on NEEMO 15, one of them was a we
simulated fire in the habitat. The other
one was a medical emergency. The medical
emergency was somebody goes outdoors.
They get a serious jellyfish sting, have an
allergic reaction to it, and it's kind of
a life-or-death situation. Now, we were
very fortunate on that mission that,
let's see, second from the left in the
top row, one of our crew members was
David Saint-Jacques. He's a Canadian astronaut. David's a medical doctor. So we aced it.
He knew exactly what to do. We just blew
through it, didn't even have to talk to
topside. They had one of the one of the
habitat technicians--there were two of
them down there too--play the victim. David saved his life, and it was all good.
Then came NEEMO 16. In NEEMO 16 we ran the exact same scenario, but we did it with a
five-minute, Mars-like delay. Five minutes one way,
five minutes the other. On NEEMO 16 we did
not have any medical doctors on the crew.
There was an ESA flight surgeon who was
topside, and he was there to help us. Now
I kind of had fun on this one because we were doing the same scenario
we'd done on 15. So I knew the story I
knew exactly what you were supposed to
do. I remembered it well. They said
okay, Steve, you get to be the victim. So I
came staggering in with my arm. And I've
collapsed on the floor, and they're
trying to figure out what to do. 
And we've got this great medical kit, and we've
got communications--with a five-minute
delay--to a talented flight surgeon.
I died. I died in this scenario. Now, there
were two interesting things about that.
One was that the crew had forgotten to
put the little sign up in front of the
webcam saying this is only an exercise.
So that led to some unintended consequences. But on top of that, what I took away from it was that
when people go to Mars for real, the
entire paradigm of Mission Control--the
entire paradigm that has existed for
decades, okay, since Alan Shepard--of how
we interact with people in space is
going to have to fundamentally change.
When you're at Mars in any kind of
dynamic situation, you're on your own.
That one-way lifeline? Tomorrow's can be
as long as 20 minutes. A lot can happen
in 40 minutes in an emergency situation.
It fundamentally changes the equation.
Let's see. Mars isn't all bad!
There's some fun stuff.
Check this out. This is one of my favorite things that we did early in
the mission. That's the moon Phobos, one
of the Martian moons, passing in front of
the sun. This is the first solar eclipse
ever witnessed from the surface of Mars.
There was no science in this observation
at all. We just did it because we could.
And that's a Martian sunset. On
Mars there's this very, very fine-grained,
smoke-sized dust in the atmosphere.The
dust is red, and so the atmosphere is
pink in the daytime. But at sunset, when
it's forward scattered through that
fine-grained dust--think of what happens
when you're in a, you know, dark, smoky
barroom and it's backlit, and it gets the
smoke, cigarette smoke, it looks blue, okay?--
turns blue at sunset. So pink in the
daytime, blue at sunset. It's the opposite of Earth.
Opportunity went on for 14 years,
traversed--it was a vehicle that was
designed to last 90 days went for 14 and
a half years; designed to drive for one
kilometer, it drove for 45. That's the
traverse that we followed. We finally
ended up in a beautiful little valley
that we called Marathon Valley.
That was where the vehicle died. Here's
the picture from
Opportunity's final resting place before
the dust storm hit us. Here's the dust
storm. This is not a real image of the
dust storm; this is simulated.
The opacity of the atmosphere got so high, but this is what actually happened at our
site. And you can see by the time it got
to its worst, you couldn't see the sun at all.
The final picture from the
Opportunity rover. I spent 16 years
trying to get these things to the launch
pad and then 15 years once we got them
into space operating them. This is the
last image we ever got. It was a
poignant moment. And you can see partway through came the end.
It's gotten a lot of media attention. This is one of my favorites.
This is from The Onion. Yes, the Millennium Falcon came to see us, y'know.
All right. So let me get back to my point
at the beginning to wrap this up.
Three different models for how we might send
humans to this terrible place, and it is
a terrible place, okay? I spent 14 years
lovingly trying to keep alive machines
that I lovingly helped build with my own
hands and experienced the Martian
environment in all of its moods, all of
its seasons, all of its storms. I've been
there, to the extent that anyone can be there.
So, human research base? Absolutely, as
soon as possible.
Mars is a compelling place to do
scientific research. It is a place where
the best research is ultimately going to
be done by humans I'm a robot guy, and we
cannot get humans to the Martian surface,
build a base there, and have them doing
research soon enough for me.
I pray that I live long enough to see it.
(I'm eating healthy foods. I'm getting
lots of exercise.)
But as a model for how we'll do scientific research? You know, if you send people there like an Apollo
crew, they spend a short while, and they
come back, they're not gonna have time to
do the stuff that you want to do. You
want to have a research base and then go,
and they can spend significant periods
of time there and really get meaningful
scientific research done. So research
bases on Mars,
absolutely. The sooner the better.
What about tourism?That's another scenario in which you go, you spend some time there,
and then you come back. You have to be very wealthy--you have to be pretty wealthy just to go to
Antarctica--you have to be incredibly
wealthy like Dennis Tito, on the left here,
if you want to be a tourist in space today.
But while I wouldn't say that anyone has shown yet that there is a robust
business model--it requires there being
significant infrastructure present in
space--there are enough people who are
thinking hard. Here's an example from
Space.com--there's gotta be somebody
from Space.com here--anyway, this is an
example of an article, a company that's
designing a space hotel. This is in
low-earth orbit, of course, very easy to
get to compared to Mars--but there's
enough interest, there's enough--maybe
enough demand, not sure about that--
that if you ask, are we gonna someday send tourists to Mars--get the research base
there first, just like in Antarctica, but
eventually the tourists might show up
spend a little time, and then they can go
back home? So I'll give that one a
checkmark, too. All right, let me get on to
colonization. I showed you
Longyearbyen in Svalbard, okay? I showed you this picture at the beginning. This
picture is beautiful, shows Svalbard,
but it's kind of misleading,
In the summertime, Longyearbyen looks like that.
This place is 600 nautical miles from
the North Pole, but it looks like that.
Why?The Gulf Stream. It is embedded in
the flow of the Gulf Stream, and so
there's this steady stream of warm water.
It dramatically affects the climate, and
even though this place is really close
to the North Pole,
I've been there in the
summertime four or five times. It's quite
lovely, okay? A better analogy is Antarctica.
Now, Antarctica is international
territory. If you wanted to take your
family there, if you wanted to build a
home, if you wanted to go homesteading,
set up shop, build a community, build a
town, nobody's going to stop you. You
could do it. You can breathe the air.
You can drink the water. There are fish
to eat, there are penguins to play with. And yet
nobody does it. Why? Because Antarctica is a terrible
place. You're laughing, but it's a
terrible place, it really is. And Mars is
so much worse, Mars is so much worse, And colonization means you go there and
have babies. You go there and you have
babies. I'm partly in State
College, Pennsylvania, today because my
six-month-old granddaughter lives here. I
wouldn't want her on Mars and, you
know, this idea of colonizing Mars has
this enormous romantic appeal to it. But
having experienced the reality of Mars
for 15 years, having had other
experiences that give me a sense of what
it's like to be in space, I truly believe
that when humans are really confronted--
real people are confronted with the
reality of trying to live their lives in
an environment that harsh--that my take
on this one is no. I don't think so.
I really believe that if we're gonna send
humans into space to live, that if we're
gonna colonize space, we have to do it in
a place that's nicer than Mars is.
Because Mars is nasty.
Whenever I give talks about the Mars Exploration Rover project, I always end them with this slide.
I wrote a book about the project called Roving Mars, and in an appendix of that book I made an attempt
to list the names of everybody who had
worked on the project up to the time
that I wrote it. There are more than
4,000 names on the list. I'm just one of
the team. This is a bunch of us. This is
down at the Cape. You can see in the
background that's the Oppertunity
spacecraft mounted on the third stage of
the launch vehicle. This is the night
that we went out to the launch pad.
For every one of us who was part of that mission
for so many years it was, in the literal
sense of the phrase, the adventure or a
lifetime. And I thank you very much for
inviting me here to tell you about it.
Thanks, Steve.
So the bad news is that we're at the
break time. The good news is that I think
we can take a couple of questions. Go
ahead, go ahead.
So are there nicer places you'd like to colonize?  What are they?
And we say "settle." We don't say "colonize."
Well, so there are other places that one
could go in space that you can imagine.
Asteroids are places where there could
be valuable resources. In my scenarios--I stuck to Mars--in my scenarios
for Mars I did not include exploitation
of resources. That's another scenario,
mining colonies. Those tend to be pretty
rugged places to live, and they tend to
be in, you know, nasty places even
on Earth. I can well imagine that if
there are resources on asteroids that
are of sufficient value that you would have
people working there for extended
periods of time--things like an offshore
oil platform or some of the early mining
colonies, that sort of thing. I mentioned
those for asteroids because those are
good places to get space resources.
Mars is one of those places where (a)
there's not a lot of resource except for
water, which is valuable, but (b) it's a
pretty deep gravity well, and you've got
to haul it back out again. So if you ever
use resources on Mars, you're probably
gonna exploit resources on Mars, you'll probably
exploit them there. So asteroids are a
possibility. I'm particularly intrigued,
when it comes to mining resources, by the
lunar polar regions, where there are rich
deposits of ice that can be used to
break it down into hydrogen and oxygen
and be propellants. And then of course
there's been talk for
many years about, you know, Gerard O'Neill and his ideas for building artificial
space stations where people could live
and work. So those are possibilities it
may be, it might be, that true settlement--
it might be that it'll never happen, that
it's just not the right place for our
species. Our species evolved in the
terrestrial environment. It's pretty well
tuned for us.
So while I'm a big believer in trying to
get industry out into space and trying
to explore space and trying to sell space to the greatest extent
possible, I'm also a big advocate for
trying to keep this place that we have
that's so wonderful, keep it still livable.
You talked about the three possibilities,  three scenarios for sending humans to Mars. What about 3A? Is there a possibility of terraforming Mars, getting it ready?
Terraforming. Okay, I said I was only going
to look a few centuries into the future.
Terraforming presupposes that you
have both the technology and the wisdom
to tailor the climate of an
entire planet to your liking.
Now one thing that we're learning on Earth right now is that the climate
systems are incredibly complex
things. And to me--I see no evidence that
anybody knows what the technology is to
terraform Mars. I don't see evidence that
we have the wisdom to change a planet's
climate to our liking. If we do at some
point in the future, I would like to
terraform Earth.
So, you know I said I'm not going to
try to gaze thousands of
years into the future, and I'm not gonna
do that because I don't think I can I
can look that far into the future. But I
really believe that terraforming is, for
now, in the realm of very deep science
fiction and is going to be for a very
long time to come. I don't think it's the
answer. Yeah.
So there used to be these discussions where scientists, many scientists would say we don't want to spend all that money on humans .
We can do so much greater exploring using much greater exploring using robots. You're clearly an expert on this topic.
When you get humans there to do research, what's
the first couple of things that a human
researcher would be able to do that you just think is too far away that...
Drill, baby, drill! Drill, baby, drill. That's
it, okay? Liquid water is not stable in
the current Martian surface environment.
And we get these intriguing hints
occasionally that there might be little
leaks of salty water somewhere, but if
you want to find real habitable
environments on Mars today you got to go
down, okay? The average surface temperature, as I said,
is -60 degrees Celsius,
but just like Earth, Mars is going to
have a thermal gradient with depth. It
gets warmer and warmer and warmer, and
sooner or later--some people think
it's hundreds of meters, and some people
think it's a few kilometers--but sooner
or later you are going to get to
temperatures where liquid water is
stable. You can go to depths of one, two,
three, four kilometers in the Earth's
crust, and there are living organisms
there that are drawing for their metabolic
energy not on sunlight, obviously, but
from the Earth's own internal geothermal
heat. So if you want to find a place
where there's a true habitable niche on
Mars today, it is probably hundreds of
meters to kilometers down. Drilling is
hard, okay? I was involved in the Mars
Exploration Rover project. where we were
able to drill this far. I've been
involved in the Mars Curiosity project.
where we drilled this far, okay? If you
want to drill hundreds of meters, it
takes enormous amounts of power, it takes
hundreds of meters of pipe. It's hard to
do. You'll never do that without humans.
So that would be my first one, is go
for life, down.
Steve, Mars Insight is supposed to be drilling this far down?
And they've had a tough time.
They're having trouble with it. Is there
anything you want to say about the current troubles?
Yeah. Drilling on Mars
is hard! Proves my point. Yeah.
So I'm actually glad that question came right before because, I mean,
drilling is a huge change to what the surface of Mars actually looks like. Can you talk
a little bit about the future planetary protection?
Oh, boy. Yeah, yeah. Yeah, the future of planetary protection. Okay, planetary protection
goes both ways, right? You worry about
forward contamination. You worry about
back contamination. Oh boy. We're on the record here, aren't we? Okay. Back contamination
is an issue that has to be treated
seriously. I'm personally skeptical that
there are organisms living on Mars that
would pose a threat to humans. If they
are living on Mars, they evolved very
differently from life on Earth. Pathogens
and their victims tend to co-evolve,
right? So my opinion--my guess, I'll call
it a guess--is that there's nothing
deadly on Mars. But guesses can be deadly,
okay? I could be very wrong. So I think
back contamination we have to take very
seriously. Of course if we send humans into
a Martian environment, they will be
people who realize that, you know,
understand the risk that they're taking.
The issue of forward contamination is a
pretty serious one.
Humans are dirty, dirty, dirty things. If
you notice that picture I showed you
right at the start, where we're wearing our
clean suits in the cleanroom, we tried
very hard to keep those rovers as free
of biological contamination as we
possibly could. Humans, you can't do that.
And as soon as the first
first human stepped foot on Mars you
have irreversibly contaminated the
planet. And so that that needs to be
thought about. It needs to be thought
about hard, because if you're going there
to find, to try to find life, and you're
going there with life, you run the risk
of, you know, putting something there and
and then discovering the thing that you
brought. I think there are ways of
dealing with this. One point is that
if you find something that is human, you
know, that is terrestrial in origin by
sequencing it and looking at what you
found and saying ah, that's a perfect
match to something that we know is a
robust organism that lives on Earth, you've
kind of got to think, okay, it's probably
a false positive. The other thing is that
any biologists will tell you that there
is such a thing as sterile technique
that you can use to sample an
environment and not, you know, contaminate
your sample. So I think forward
contamination of Mars is a very serious
issue from a scientific perspective, one
that we have to treat very seriously,
but I think there are ways of doing it
that will not compromise the science that we're trying to do.
You know, a good example is these drill holes
that go down, you know, kilometers and try
to see if they're organisms down there.
And of course you're going down there
with a dirty drill bit that's been
handled by people at the surface. And
techniques have been developed for dealing with that and telling the deep guys from the shallow guys.
Thank you. Thanks, Steve!
