NASA Astronomer Steven Squyres

DATE March 29, 2004 ACCOUNT NUMBER N/A
TIME 12:00 Noon-1:00 PM AUDIENCE N/A
NETWORK NPR
PROGRAM Fresh Air

Interview: Steven Squyres discusses the work of the Spirit and
Opportunity rovers on Mars
TERRY GROSS, host:

This is FRESH AIR. I'm Terry Gross.

My guest, Steven Squyres, is spending his days communicating with Mars. He's
the principal scientific investigator for the twin Mars rovers Spirit and
Opportunity. Squyres is also a professor of astronomy at Cornell University.

The two rovers are equipped with sophisticated instruments to search for
evidence that the planet was once wet enough to be hospitable to life.
Squyres and his team helped design and test those instruments, which are
currently gathering and transmitting information about the planet. Squyres
has been analyzing the data as it comes in. Spirit was launched last June;
Opportunity was launched in July. They landed on Mars in January. We invited
Squyres to talk with us about some of the mysteries of the planet and some of
the larger questions about life itself that he hopes the rovers will help us
answer. Let's start with the focus of the current mission. I asked Squyres
why the search for water is so important.

Professor STEVEN SQUYRES (NASA; Cornell University): Well, you think of water
as being something that we believe to be a necessary condition for life. I
mean, the thing that is driving our interest in Mars is the possibility that
life may once have taken hold there. And when you ask yourself what
conditions are required for life, at least as we know it, there are a few
things. You need to have some source of energy. Sunlight works just fine; so
does geothermal heat under some circumstances. You need to have the right
chemistry: carbon, hydrogen, oxygen, so forth. And then for all life that we
know of on Earth, you must have liquid water. There are no instances that we
know of of life on Earth that don't require liquid water. And so that is sort
of the thing that guides our search for life on other worlds--is looking for
water.

GROSS: So what's the best evidence you have so far that there was once or
there is still water on Mars?

Prof. SQUYRES: Well, certainly, you've got to be a little careful about how
you use the phrase `water on Mars.' Scientists get a little sloppy with their
terminology. And some people use the phrase `water on Mars' to mean the H2O
molecule is on Mars in whatever form you can imagine it: vapor, solid, what
have you. If you define it that way, we know there's lots of water on Mars.
It's been known for decades, OK. There's lots and lots of ice at the martian
poles. There's water vapor in the martian atmosphere. This has been known
for a very long time.

If you're talking about liquid water on Mars, that's a very different matter.
No one has ever found liquid water on Mars today, but we're finding, I think,
pretty compelling evidence for the existence of liquid water on Mars in the
past. From the Mars exploration rover mission, the best evidence for that has
come at the Opportunity landing site at Meridiani plenum, where we have found
rocks that show very, very compelling evidence that they were affected by the
action of liquid water and, indeed, probably laid down in liquid water.

GROSS: What can a rock tell you about the presence of water?

Prof. SQUYRES: Well, there's a bunch of things it can tell you. I'll give
you two examples. One is you can find minerals in the rock that require water
for their formation. Every rock-forming mineral that you can name has a
specific set of conditions under which it could form. You've got to have the
right chemistry, you've got to have the right temperature, you've got to have
the right conditions to make the mineral. And so you can think of the mineral
as being kind of a clue, as being sort of like a fingerprint that can tell you
something about what the conditions were like. And we're finding minerals in
these rocks that require liquid water for their formation. So that's one good
example.

Another thing that we're finding in the rocks at Meridiani plenum, which is
where Opportunity is, is we're finding the distinctive signature produced in
layered sedimentary rocks when they're deposited in liquid water; in
particular, when they're deposited in water that's flowing. When water flows
along, it can make ripples in the sand on the bottom of the water, and those
ripples can then be preserved over geologic time. And when you find that kind
of features in a rock, they're a clear indicator that water was there and was
flowing at the time the rocks were laid down.

GROSS: Now you think you've found evidence that there was actually saltwater
once on Mars.

Prof. SQUYRES: Mm-hmm.

GROSS: Why is that an important development, that it might have been
saltwater?

Prof. SQUYRES: Well, I think one of the things that's most important about
that is that by having minerals that precipitate from liquid water, it forms
an environment in which you can actually really preserve evidence what was
going on in the water. The water provides a medium that might be able to
support life. I mean, liquid water is a nice, habitable environment, and
there are lots and lots of organisms that can live in liquid water. But if
all you had was a habitable environment, and then that environment was
transient and went away and there was no way of preserving what might have
been in the water, then it's going to be hard to read that record.

The nice thing about minerals that are precipitated from liquid water, such as
when you evaporate water away and you leave salts behind, is that those
minerals can actually preserve--within their crystal structure can sort of
trap, like bugs in amber, whatever was in that water. So if you have
interesting organic molecules, if you have biochemistry going on, if you have
actual, you know--if you have cells, if you have actual microorganisms that
are left behind, they can become trapped within those salty deposits. It's a
very good way of preserving evidence of whatever was going on in the water.

GROSS: So what kind of life might the water that might have once been on Mars
supported?

Prof. SQUYRES: I don't have any idea. I mean, your gut tells you that it was
almost surely, if it existed at all, extremely primitive. And my reason for
saying that is simply that if you look over most of the Earth's history, the
life forms that existed on Earth up until, you know, just 5, 600 million years
ago were, for the most part, very primitive and simple. And they didn't
really get diverse until pretty late in the planet's history, and that's on a
planet that's had massive global oceans for virtually its entire history.

So Mars we're probably talking about much less water activity, water bodies
that might have been transient--you know, there for a little while, and then
they dry up and go away, that sort of thing. So it's hard for me to imagine
life developing to some great level of complexity on Mars. In fact, it's far
from certain that life developed there at all. But, you know, who knows?

GROSS: So if there was once water and if there was once life on Mars but
there no longer is, what would that mean? That it all kind of came to an end?
That it didn't work?

Prof. SQUYRES: Well, that's a good question. There's evidence that in the
past on Mars conditions were warmer and wetter and more Earthlike than they
are today. And one of the big puzzles of Mars has always been: What changed?
You know, what happened? Why did the water dry up? Why did the climate get
cooler? We don't have really good answers for these questions. It's always
been a bit of a mystery. But, clearly, the evolutionary paths of Earth and
Mars have diverged a bit over time.

GROSS: You're looking for signs of water. Signs of water would lead you to
think that there might be signs of life. So you're looking for signs of
former life also. But you don't know what kind of life, so you don't know
exactly what you're looking for. So how do you go about looking for signs
that there was life on Mars?

Prof. SQUYRES: Well, we're not looking for signs of life with this mission.
What this mission is about is finding the right stuff for preserving evidence
of life. It's about finding what was once a habitable environment. And we've
done that. What's then going to happen is--you got to look at this mission as
being part of NASA's longer-range program of Mars exploration. Within another
decade or so the plan is to go to Mars and to actually set down on the
surface, collect some samples, quite possibly from very close to where we've
landed at the Opportunity landing site, and bring them back to Earth and put
them in terrestrial laboratories and be able to take those samples apart, in
some cases, almost molecule by molecule and go through them and really look in
detail for evidence of whatever was in that water.

GROSS: And when do you expect you'd actually be able to get samples?

Prof. SQUYRES: Well, that's a good question. It sort of depends on a whole
lot of both technical and financial issues that are a little bit cloudy right
now. But my hope is that in the early part of the next decade, we'll be
bringing samples back to Earth.

GROSS: You know, we had a difficult time scheduling this interview with you
because we had to coordinate our clocks. We, on FRESH AIR, are on East Coast
time whereas you are on Mars time.

Prof. SQUYRES: That's right. Yeah.

GROSS: What is Mars time, and why are you on it?

Prof. SQUYRES: Well, one of the things that really complicates our operations
of these vehicles is that they are solar powered. They work during the
daytime, and they sleep at night. And they don't care if it's daytime or
nighttime in New York or in Pasadena. They only care if it's daytime or
nighttime on Mars. The martian day is not 24 hours long. It's 24 hours and
39 minutes long. And that 39 minutes plays havoc with our lives. Because
these rovers operate on kind of a martian daily rhythm, those of us here on
Earth, who are entrusted with their care and feeding, have to live on their
schedule. And so each day we have a planning meeting, at which we get
together, we look at the data that we got today and we plan what we're going
to do on Mars tomorrow. And because of the difference between Earth time and
Mars time, if that meeting's at noon today, then tomorrow it's at 12:39, and
the day after that it's at 1:18. And it progresses around, and so two and a
half weeks later it's in the middle of the night. And we've been doing this
for, mmm, 11 weeks now, living on Mars time. It does kind of mess with your
head a little bit.

GROSS: How?

Prof. SQUYRES: Oh, because you're living on a martian schedule at the same
time you're living on this planet, Earth. And so you're exposed continuously
to daylight and darkness on a 24-hour schedule. You're exposed to, you know,
meetings that we have to go to. The people who actually live and work here in
Pasadena, the people who are, you know, employees of the Jet Propulsion
Laboratory and are engineers who work here, their families are living on Earth
time, and they're living on Mars time. It makes life difficult.

GROSS: Are you getting any sleep?

Prof. SQUYRES: Yeah. You know, you get an extra 39 minutes of sleep every
day.

GROSS: Oh, that doesn't sound bad.

Prof. SQUYRES: Yeah. As long as you stay on a hard martian schedule and you
don't let the outside world intervene, it's pretty good. When it gets tough
is if you're in the part of the cycle where you're sleeping in the daytime and
working at night and somebody calls a meeting at 2:00 in the afternoon, that's
when life gets unpleasant.

GROSS: Right. What is your typical day like now?

Prof. SQUYRES: Well, let's see, I typically wake up at about 3:00 in the
afternoon Mars time, come into the office at the Jet Propulsion Laboratory.
And the day sort of begins for the science team when the data from the
spacecraft comes down that day. We're getting most of our data these days
through an orbiter called Mars Odyssey that's in orbit around Mars and serves
as a communications relay satellite. And that will overfly the Opportunity
rover, which is the one that I'm working on right now. Typically, oh, about
4:30, 5:00 in the afternoon the rover will shoot a bunch of data up to the
orbiter; the orbiter will shoot the data down to Earth, and then we'll look at
it and we'll see what happened.

So let's say on a given day we might have planned a drive. There's a rock
that's 10 meters away that we're very interested in, and we're going to drive
to that rock. So we commanded the rover on the previous day to drive to the
rock and then when it gets there to take some pictures, so we wait and we see
those pictures. And the thing that you're waiting for in a situation like
that is: Did we actually get to the rock? Did the navigation work properly?
Did the wheels slip too much and cause us to fall short? You know, was there
some kind of fault that took place on the rover, or did we actually get to
where we wanted to? So we'll look at the data. We'll have typically an hour
or hour and a half to look at the data and figure out what we want to do.

And then we all gather in a big room; this is the whole science team now, plus
a bunch of the engineers. And we'll sit and we'll plan, in a meeting that
typically only takes about an hour, what activities we want to do on Mars the
next day. So, for example, if we drove to a rock and we find that, yes, the
rock is right where we want it to be and it's now someplace where we can reach
out and touch it with our arm, we might plan a series of events on the rover,
in which we would reach the arm out and take some pictures with the
microscope, which is on the end of the arm, or grind a hole in it with our
rock-abrasion tool, which is on the end of the arm, or what have you. So
we'll plan those activities.

At that point most of the people on the science team go home. A few of us
stay in for a while, and then a bunch of new people come in. And it's the job
of that group to formulate the exact sequence of commands, the exact computer
language that will be transmitted to the rover the next morning to instruct
it to do what we want it to do on the next sol, the next martian day; we call
them sols. And then we just repeat the cycle, and we do it again and again
and again. And we've been doing it for a couple months now.

GROSS: What do you call a typical martian day?

Prof. SQUYRES: A martian day we call a sol, S-O-L. We found very early, in
fact, that that terminology dates back to the Viking mission back in the '70s.
When you start saying, `Well, we're going to do it five days from now,' do you
mean five Earth days, or do you mean five Mars days? And when a word like
`day' becomes ambiguous to you, you find that you need some new terminology.
So a martian day we call a sol. And then what happened on Mars the previous
day we say happened yestersol.

GROSS: (Laughs) Why `sol'?

Prof. SQUYRES: Sol is--it's from the Latin word for sun.

GROSS: My guest is Steven Squyres, NASA's principal scientific investigator
for the twin Mars rovers Spirit and Opportunity. We'll talk more after a
break. This is FRESH AIR.

(Funding drive)

(Soundbite of music)

GROSS: Steven Squyres is my guest, the principal scientific investigator for
the twin Mars rovers Spirit and Opportunity.

You helped design some of the tools that you are using...

Prof. SQUYRES: That's right.

GROSS: ...to do research and capture information from Mars. Can you talk
about some of kind of coolest gizmos that are being used right now?

Prof. SQUYRES: (Laughs) Yeah. Well, we've got a lot of cool gizmos. You can
sort of take the scientific tools on this vehicle and break them down into two
pieces. One part is for looking off into the distance, and then the other
part is for kind of getting up close and personal with the rocks, once we've
found good ones. For looking off in the distance, we've got two instruments.
One is just a spectacular set of cameras; we call them pan cam. And they're
very, very high-resolution cameras. I mean, most of the really spectacular
images that you've seen and all of the color images came out of the pan cam
camera. They're the equivalent of 20/20 vision. We gave our rover geologists
20/20 vision, so that they could look off into the distance and find
interesting targets from quite far away. So that's one of the instruments for
looking off in the distance.

The other one is--it's called MiniTES, which is short for Miniature Thermal
Emission Spectrometer. It's an infrared spectrometer that can look off into
the distance and, from a distance, tell you something about what rocks are
made of. Once we have found targets, rocks, that we think might be
interesting for one reason or another, we can then, of course, drive over to
them because the rover has the ability to move. And then on the front end of
the rover there's an arm, and it's got a shoulder and an elbow and a wrist.
It's basically the same dimensions as a human arm. And on its hand it's got
four fingers. One of those is a microscope for looking at the rocks, you
know, at really high resolution, really detailed. There are two other
spectrometers, and each of those is aimed at telling us in much more detail
about the composition of the rock: what minerals are there, what chemical
elements are there. And then, finally, we've got this thing we call the RAT,
R-A-T, rock abrasion tool. And what that is is a grinding tool that we can
press up against the rock, and it can grind away the outer layers of a rock
and kind of open a window into the interior of the rock that the other
instruments can then look into.

GROSS: Wow. And how do you control these tools? Do you have, like, a
joystick or a keyboard?

Prof. SQUYRES: You know, I wish you could joystick it, right? You know, what
I'd love to be able to do, especially when we're doing a drive, is to just sit
there with a joystick and steer the vehicle, you know, around the rocks and
that kind of thing. But the reality is that Mars is so far away--I mean, even
when we landed, which was when Mars and Earth were closest to one another, it
took 12 minutes traveling at the speed of light for a command to get to Mars
and then another 12 minutes traveling at the speed of light for the signal to
get back. And the planets have moved much farther apart, and so it's much
more time now. So you don't have any real-time control.

So what you have to do is you put together a list of commands, and it's done
by people sitting at computer monitors with keyboards and, you know, a mouse
and that kind of thing--and putting together a list of commands. And then all
the commands at once, everything that the rover's going to do for an entire
day, is transmitted to the rover; receives the commands and then, totally on
its own, it just goes off and does all of those things. So we've actually
endowed it with a certain amount of autonomy, a certain amount of artificial
intelligence, I guess you could call it, so that it can do those things by
itself without the ground intervening because we're simply too far away to
help it.

GROSS: How fast can the rovers drive?

Prof. SQUYRES: Pedal to the metal, just as fast as you can go, they're about
six centimeters a second. That's about how fast they'll go. It's like two
inches in a second. They don't exactly go screaming along. Actually when we
drive them, we actually drive them more slowly than that because we sort of
like to have them stop and take a look around every so often, think a little
bit about what the obstacles ahead of them might be. But we think that when
we get out onto the plains of Meridiani, in particular, that we might be able
to drive as much as 100 meters in a single martian day. The Gusev, where
Spirit is, the terrain is much rockier and more rugged, and we've been
typically averaging maybe 30, 35 meters a day, something like that.

GROSS: Do you start to think of the rovers as being alive because of the
artificial intelligence you've designed into them?

Prof. SQUYRES: That's only one of the reasons that we think of them as being
alive. I mean, you've got to realize some of us have been working on this
concept for more than a decade and working on these particular pieces of
hardware for better than four years now. And, you know, you endow these
things with your hopes, your dreams. You just pour all your hopes and efforts
into these things. And, yeah, they very much become alive for you, not just
because of the software that we've put into them and the artificial
intelligence and the fact that they get a little cantankerous from time to
time...

GROSS: (Laughs)

Prof. SQUYRES: ...but just the fact that they're sort of extensions of
ourselves. And when they're doing well, we're proud, and when they're having
trouble, we get worried. And, you know, I mean, I would use a word like
`love' very advisedly when talking about a hunk of metal, but we love these
machines.

GROSS: And did you give them any personal effects or anything to take to
Mars, you know, things of your own?

Prof. SQUYRES: (Laughs) That's a good question. Yeah. You know, everybody
likes to sign their work, I guess. And so stashed away in various places on
both vehicles are lots and lots of little things, all kinds of little things,
you know: people's initials, plaques with the names of, you know, engineers
who worked hard on these things. There are lots of little personal touches,
yes.

GROSS: Steven Squyres is NASA's principal scientific investigator for the
twin Mars rovers Spirit and Opportunity. He's also a professor of astronomy
at Cornell University. He'll be back in the second half of the show. I'm
Terry Gross, and this is FRESH AIR.

(Soundbite of music)

GROSS: Coming up, more of our interview with Steven Squyres, NASA's principal
scientific investigator for the twin rovers Spirit and Opportunity, which are
currently investigating Mars.

(Soundbite of music)

GROSS: This is FRESH AIR. I'm Terry Gross back with Steven Squyres, NASA's
principal scientific investigator for the twin Mars rovers Spirit and
Opportunity. They landed on Mars in January and are searching for evidence of
that Mars once had water that could have supported life. Squyres' team helped
design and test the instruments that are gathering the information, and he's
been spending his time analyzing the findings as they come in. In order to
stay in sync with the rovers, he's living on Mars' time. To distinguish an
Earth day from a Mars day, which is 24 hours and 39 minutes, his team calls a
Mars a day a `sol.'

What's been the most exciting moment for you so far?

Prof. SQUYRES: Oh, my goodness. Wow. It's hard to pick any one. I'll give
you two.

GROSS: Sure.

Prof. SQUYRES: One was when Spirit first rolled off of its lander and had six
wheels in the dirt. You know, the landings were great, the launches were
great. But launches, landings, you know, when we shipped the hardware to the
cape, all of those were things that I sort of viewed as kind of milestones
along the way. But we weren't really ready to begin our exploration, the
vehicle wasn't really in its native environment, until it had six wheels on
martian soil. And as soon as we had Spirit with six wheels in the dirt, you
know, I knew we had made it; we had gotten to Mars. And that was a wonderful
moment.

The other one, I think, was the moment at which, for me, I finally realized
that, my goodness, yes, at the Opportunity landing site, we were looking at
rocks that were showing the distinctive signs of liquid water. And that was
an interesting thing because that was a story that kind of unfolded slowly.
We would have one clue and then another and then another and another. And
sooner or later the clues add up to tell a story. But the thing that was
interesting was that, you know, I've got a hundred and some-odd scientists on
my team, and everybody comes into the mission with their own set of kind of
prejudices and beliefs and expectations about what we're going to find on
Mars. And some people came into the mission, you know, thinking it was really
likely we'd find evidence of water, and some were very skeptical. And it was
very interesting to watch my whole team and watch as each clue was revealed to
us by the rover, you know, at what point each person sort of fell over that
cliff and decided, `Oh, yeah, we really are looking at evidence of water.'

I remember the exact moment that it was for me. There was a particular image
that showed some features that I just--it was so compelling that I became
convinced. But for each person, it came at a different time. And it was very
interesting to watch the team as this realization grew on us.

GROSS: What was one of the worst moments during this mission?

Prof. SQUYRES: Oh, that's easy. The worst moment since we landed was the
anomaly that we had with Spirit on sol 18. On the 18th sol of the mission, we
lost contact with the vehicle. And, in fact, it was worse than that; we lost
control of the vehicle. There was a problem with the software on board the
vehicle. We didn't know that at the time. We had no way of knowing what was
going wrong because the only symptom that we had was that, you know, the
vehicle wasn't talking to us. And there was just a heart-wrenching two or
three sols there where the vehicle was beyond our control. We knew that it
was awake all night, kind of thrashing around and burning the batteries down.
And it was a very, very frightening thing.

And then some just brilliant detective work by some of the software engineers
here at the Jet Propulsion Laboratory--they figured out not only what was
probably going wrong but a way to bypass the problem and get the vehicle back
under control. And so after about three sols of this, which it was right
before Opportunity landed, too--it was very, very close--they managed to get
control of the vehicle. And we finally recovered completely, and we're off
and running again. But that was definitely the worst moment since we've
landed.

Now prior to that, before launch, we had a lot of bad moments, just an awful
lot of them. The development of this mission was just an emotional
roller-coaster ride. We had a very short period of time to do it in, and we
had all kinds of failures. We had parachute tests that failed; parachutes
that we were relying on that, when we deployed them, just shredded, just
ripped to ribbons. We had air bags that we were counting on that, when we
tested them, just tore, ripped. We didn't have our first successful parachute
test until eight months before we launched. So it was--there were a lot of
very, very disheartening, frightening, terrifying times during the development
of this thing.

GROSS: If you're just joining us, my guest is Steven Squyres, and he's the
principal scientific investigator for the twin Mars rovers, Spirit and
Opportunity.

Can we talk a little bit about the surface of Mars?

Prof. SQUYRES: Sure, one of my favorite places.

GROSS: (Laughs) What is the most and least recognizable aspects of it? If
you were to compare the surface of Mars to the surface of Earth, what looks
the most the same and what looks the most different? Let's start with the
same.

Prof. SQUYRES: Well, it depends a lot on where you are. That's a hard
question to answer.

GROSS: OK.

Prof. SQUYRES: You know, if you look at the two Viking landers and the
Pathfinder lander and our landing at Gusev crater with Spirit, all of those
places look pretty similar. They were kind of flat, boulder-strewn plains.
They had kind of what's become a very familiar martian look to them. But
that's deceiving, that's misleading, because the reason that those places all
look much the same is that there are certain rules, certain criteria, that you
have to follow for landing safely on Mars, and they tend to lead you to flat
plains. When we landed at Meridiani plenum with Opportunity, all of a sudden
we saw a very different Mars. We saw a place that was unlike anything that
we'd seen on Mars before. And the fact is that if you could go to the
spectacular places on Mars, if you could go to the mountainous places, if you
could go into the deep canyons, you could see some incredible scenery,
spectacular topography. And we just simply haven't been able to build landers
that can safely land in these extremely dangerous places yet. That will come
someday, but right now we don't have that capability.

So if you sat down on the surface of Mars at kind of a typical place, the
things that would be familiar would be--you'd see rocks lying around. You
would see drifts of sand and dust. I mean, it doesn't look like many places
on Earth. It doesn't look like most places on Earth. But if you go to some
of the world's most desolate deserts, places where there's no vegetation,
places where you have--you know, where there's no rain, where the primary
geologic activity involves wind blowing stuff around, there are places like
that in the Atacama Desert in South America, in Dry Valleys in Antarctica,
some places that look sort of like that in Iceland actually. You can see
places that look very much like Mars.

The things that would be different: Well, first of all, the sky's pink, which
is a little weird (laughs).

GROSS: Yeah.

Prof. SQUYRES: So that would catch your eye immediately. You know, it's
brutally cold. It will get reasonably warm during the daytime but then go
down to 100 degrees below 0 at night. So it's a pretty tough place to
operate. The air is extremely thin. It's made of carbon dioxide; you can't
breathe, so you'd have to be in a space suit. The gravity is only one-third,
so if you can jump two feet into the air on Earth, you could jump six feet
into the air on Mars, which would be kind of cool. It would be very
unfamiliar. You'd have the pink sky. You would have a lot of things that
didn't look Earth. But it would look more Earthlike than if you were standing
on the surface of Mercury or Venus or the moons of Jupiter or Saturn or what
have you.

GROSS: How do you get the technology, you know, these kind of robotic devices
that you have up there--how do you get them to survive in the cold and without
the gravity?

Prof. SQUYRES: That's actually one of the toughest challenges that we
face--is coming up with designs that can survive the environmental conditions.
There's a bunch of environmental conditions that you need to worry about; one
of them is the environment of launch. Just strapping something on top of a
rocket, you go through very intense acceleration, very intense vibration. You
have to test all of your hardware to make sure it'll survive that. So the
hardware that we build has to be pretty sturdy, pretty beefy, just so it can
take that. There's a pretty substantial jolt when you land. You know, you
hit the surface at what might be, you know, 20, 25 G's, and that's a pretty
solid kick. All of our hardware gets tested for that.

They're terrifying tests to watch. You know, you build this hardware, and you
work on it so carefully and lovingly. And then you strap it on top of this
vibration table, and it starts to shake and makes this violent noise. And you
can see it vibrating, and you can almost hear it screaming out in pain
sometimes. And it's a little heart-wrenching to put your hardware through that
test, but you have to do it. Designing the hardware to withstand these
enormous excursions, these enormous variations in temperature, is very hard.
What happens, of course, is when you go through--you might go through 100
degrees centigrade between the highest point in the day and the coldest point
in the night. And designing hardware to withstand that is difficult because
things are expanding and contracting and expanding and contracting. So we
devote an enormous amount of energy to picking materials so that when they
expand and contract, they do so by similar amounts, and so you don't have big
gaps forming and things crushing together and that kind of thing.

And then we test, and we test and we test and we test. And we test everything
to more extreme conditions than we'll see on Mars. Every piece of hardware on
that rover has been through 270 thermal cycles...

GROSS: Wow.

Prof. SQUYRES: ...from hot to cold to hot to cold. And the magnitude of that
thermal cycling is 15, 20, 30 degrees higher than you actually experience when
you're on Mars. And, you know, we test and we--that was part of what made the
development of this thing such a tough struggle, was getting all that testing
done in the very limited time that we had.

GROSS: Do you think there'll be any cool things coming out of the things
you've designed for Mars that will kind of filter down to the everyday level?

Prof. SQUYRES: I very much doubt it. You'd be surprised, I think, to hear
that much of the technology that we use is actually far more primitive than
one finds in just everyday computer goods. I mean, the processor in your
laptop computer is far more powerful than the processor, the computer, in our
rovers because of the fact that you can't go out there and fix it. Because of
the fact that once you strap it on top of that rocket and shoot it off, you're
never going to see it again, everything has to be ultra, ultra reliable on
this vehicle. And so we actually tend to use very tried and true technology;
in some cases, stuff that's been around for a long time. I mean, the computer
on board our rover was a screaming hot machine about 15 or 16 years ago
(laughs). But it's pretty primitive by today's standards.

GROSS: My guest is Steven Squyres, NASA's principal scientific investigator
for the twin Mars rovers Spirit and Opportunity. We'll talk more after a
break. This is FRESH AIR.

(Soundbite of music)

GROSS: My guest is Steven Squyres, NASA's principal scientific investigator
for the twin Mars rovers Spirit and Opportunity.

During the Cold War space exploration was part of the race for space...

Prof. SQUYRES: Yeah.

GROSS: ...was part of a competition between the United States and the Soviet
Union. And that's really--it's not political in that sense anymore. I don't
think there's anybody close to the United States in terms of space
exploration, and there's nobody, you know, nipping on our tail there. So is
that a relief for you to just do this as pure science and not have it be part
of, like, the Cold War or some other similar political contest?

Prof. SQUYRES: Yeah. I think everything that we do is simplified by not
being burdened with a lot of political baggage. In fact, the exploration
that's going on right now is very international in character. I mean, yes, we
have the two US Mars-exploration rovers on the surface of Mars right now.
But, for one thing, one-third of the scientific payload on our rovers is
provided by foreign countries. Two of our spectrometers are provided by the
German space agency. And then you look at other missions that are going on
right now. The European Space Agency, ESA, has an orbital called Mars
Express, and it's in orbit around Mars right now, and it's doing fantastic
stuff. So Mars exploration has become a very international venture, and I
think that just benefits everybody.

GROSS: You are now looking at some really basic questions: Are there signs
that there was water on Mars? And if there was water on Mars, did it actually
support life on Mars? And if it supported life on Mars, what kind of life
might it have supported? Are there, like, bigger questions underlying those
questions that you're interested in, like how was the universe created? You
know, what is life?--all those like--the real big ones?

Prof. SQUYRES: Yeah, I think there are big ones, and, you know, that truly is
what motivates this--is the big questions. If you don't have truly big
questions motivating you, you've got to ask yourself: `Is it really worth the
effort that we're putting into it?' I think the big question that really
motivates the research that we're doing is: How prevalent is life through the
universe, and how did life first come into being? And we can address both of
those potentially at Mars. If we go to Mars and we find that life did take
hold there, then not only does that tell us something about the ability of
life to take hold on another planet in this solar system, but given the
multitude of planets that are out there around other stars--and
astrophysicists continue to find new planets around other stars--it
immediately--if all you've got is one instance of life in the solar system, if
you only know of one place in the whole universe where there's life, you have
no way of knowing how common a phenomenon it is. But if you've got two
independent instances of life in this one very same solar system, it takes no
great leap of logic or imagination to believe that life might be fairly
common throughout the universe because there are so many other planets out
there.

The other thing is we can potentially learn things at Mars about how life came
into being. Life developed on Earth; we know that because here we are, OK?
But what we don't know is how life first came to be. Life first came to be
very early on this planet. And when the Earth's geologic record sort of first
emerges, life is already there. If you want to try to find evidence on Earth
of how life first arose, you can't find it because the rocks that date from
that period in time are gone. They've been destroyed by tectonic activity, by
volcanic activity. Earth has been a geologically active planet, and it's
wiped out the evidence. Mars has been less active. Vast areas of Mars are
covered by rocks that are four billion years old or older. And so if life did
take hold on Mars, not only, you know, might we be able to go there and find
evidence that that took place, but we might be able to find evidence in the
rock of how life first originated in a way that we could never hope to here on
Earth.

GROSS: How long can the rovers function in Mars if things go smoothly?

Prof. SQUYRES: That's a real good question. We don't actually have a good
answer for that. The design lifetime of the vehicles was intended to be 90
sols, 90 martian days. That doesn't mean that the wheels are going to fall
off when the sun comes up on the 91st sol. It just basically means that
that's when the warranty expires. And how long they're actually going to last
depends on how much dust builds up on the solar arrays, how well the power
system and thermal system on the vehicles perform. We've gotten enough data
now from the vehicles' performance to date to be able to run projections of
their lifetime out in the future. And we've run those projections out to, you
know, 200-plus sols, and in the projections the vehicles are still doing fine
at that point. And, you know, after a while the seasons change on Mars. Of
course, what's happening now where we are is it's drifting later and later in
the year, and the days are getting shorter and there's less sun. But after a
while, the seasons change and the sun starts coming back again.

So these things could last a good long time, and, in fact, it might not be
dust buildup or power system or what have you that only limits their lifetime.
It might be something else, like pieces wearing out. We're going to try to
get as much out of these vehicles as we possibly can.

GROSS: So you're sticking with them as long as they run?

Prof. SQUYRES: You bet.

GROSS: What's next for you after this mission?

Prof. SQUYRES: Long rest. A long rest. This has been an exhilarating but
exhausting experience. You know, we have a great deal of data now. It's
going to take us a long time to do all the analysis and write it up and
publish it. There are certainly other missions to Mars ahead. Personally I'm
involved at a low level in the next mission to Mars. It's an orbiter that's
going to fly in 2005. So I'm looking forward to Mars missions. But the Mars
missions in my personal future I want to be ones where I can have a lot of fun
but a bit less responsibility.

GROSS: Right. And what's the mission in 2005?

Prof. SQUYRES: The mission in 2005 is called MRO; that stands for Mars
Reconnaissance Orbiter. It's a great big, very capable orbiter that has on it
some fantastic instruments to look down from space. It has a spectrometer
that should be able to find the spectral signature of rocks, like the ones
that we found at the Opportunity site on other places on Mars, if they exist.
It's got a camera system that has a resolution that's, like, 30 centimeters
per pixel from orbit. I mean, we'll be able to see the rovers again, which
will be kind of neat. So it's going to be a fantastically powerful mission,
and it's going to be very exciting.

GROSS: How do you think you're going to feel when the rovers stop operating
and the mission is officially over?

Prof. SQUYRES: It's going to be a very sad day when the rovers are done. You
know, we knew when we launched them that we were, in effect, sending them on a
suicide mission. We knew that they weren't going to come back. Even
launching them felt a little sad. You know, I had always expected that launch
would be just this wonderful, joyful moment. And, in fact, as I stood there
on the beach and watched the rocket climb away, I really did feel some pangs
of sadness because I knew I wasn't going to see these things again. So, yeah,
when that day comes when they stop talking to us, as it surely will, it's
going to be rough, you know. But, boy, they've done such a wonderful job.
You know, they will have done what we asked them to do and more.

GROSS: Well, Steven Squyres, thank you so much. Good luck with the rest of
the mission. And thank you for spending some of this sol with us.

(Soundbite of laughter)

Prof. SQUYRES: You're very welcome. I enjoyed it.

GROSS: Steven Squyres is NASA's principal scientific investigator for the
twin Mars rovers Spirit and Opportunity. He's a professor of astronomy at
Cornell University.

This is FRESH AIR.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Review: Graham Parker's new album, "Your Country"
TERRY GROSS, host:

With his band The Rumor, Graham Parker has been releasing records since the
late '70s as part of Britain's pub rock movement. His 1976 debut "Howlin'
Wind" caught the punk rock wave, and he hit a commercial high point in 1981
with his acclaimed collection "Squeezing Out Sparks." Since then he's
released regularly without great commercial impact while retaining his cult
following. Rock critic Ken Tucker says Parker's new solo album called "Your
Country" isn't among Parker's most consistent, but it contains a couple of his
finest compositions.

(Soundbite of music)

Mr. GRAHAM PARKER: (Singing) I walk along a lonely path, spotlight in my
eyes, try to make the people laugh instead of cry. I hang myself out on the
edge for all the world to see. Let them know this funny guy is really me.
And anything...

KEN TUCKER reporting:

Graham Parker commences his new album "Your Country" with a self-deprecating
song called "Anything for a Laugh." It's hard to know whether he means it.
Parker has never been one to pander to a crowd or doing anything for a laugh.
In fact, he's never evinced much of a sense of humor, a quality that's always
knocked him down a rung or two in my ranking of pub and punk rockers. Parker
has been most effective at bitter ruefulness, as when his problematic dealings
with his late '70s label Mercury Records resulted, once he had fulfilled his
contractual obligations, in the wonderfully splenetic song "Mercury
Poisoning." But these days Parker, now in his 50s, is less mellow than
resigned. Melancholy and evocations of the past are what he does best here on
this song, "Nation of Shopkeepers."

(Soundbite of "Nation of Shopkeepers")

Mr. PARKER: (Singing) I come from a nation of shopkeepers, window cleaners,
tough accountants and bookkeepers. I run through the station with a...

TUCKER: That's Graham Parker evoking Winston Churchill's image of Britain as
a nation of shopkeepers as a point of pride. Where most of "My Country" is
filled with his earnest but awkward attempts to approximate a kind of British
country music synthesis, part Nick Lowe, part George Jones, a song like
"Nation of Shopkeepers" is striking for its precise details about Parker's
life in the 1970s. This former gas station attendant remembers what it was
like to get dressed up in what were then fashionable items, such as the pointy
toed boots whose slang name was brothel creepers.

(Soundbite of "Nations of Shopkeepers")

Mr. PARKER: (Singing) Yeah, I come from a nation of shopkeepers, car
mechanics, plumbers, mates and innkeepers. And I run, I run, I run down the
true path past the lockkeepers in my pinstripe, my Dicky bow and my brothel
creepers. And you can...

TUCKER: There's another tune on this album called "Queen of Compromise," and
on too many songs here, Parker is a prince of compromise nudging himself
halfheartedly into honky-tonk rhythms. There's only one other really
first-rate song on this album. It's called "Things I've Never Said." It's a
complete success as a bit of faux country complete with pedal steel guitar and
gets at what sounds like a middle-aged man's true regret.

(Soundbite of "Things I've Never Said")

Mr. PARKER: (Singing) If I could bring the sky a little closer to the ground
and make the world turn around a little slower, if I could pry the lid off of
this weight that holds me down and understand her heart and would have known
her, and if I ...(unintelligible) cold and dead, I curse my empty head, if
only I could say the things I've never said.

TUCKER: On an album that finds Graham Parker crooning a terribly maudlin
version of The Grateful Dead's already mawkish "Sugaree," an original like
"Things I've Never Said" stands out all the more as a piece of meticulous
moodiness, a statement of self-blame scrubbed clean of self-pity. If only
Parker had said things like this much more often in the past, he might not be
regretting his lot in life so much now.

GROSS: Ken Tucker is critic at large for Entertainment Weekly. He reviewed
Graham Parker's new CD, "Your Country."

(Credits)

GROSS: I'm Terry Gross.
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