Space exploration began with dreaming. Thousands of years of humans staring
into the heavens and wondering, "How did this begin? What else is out there?"
The earliest answers were given in myth and poetry.
Now, they are sought by space-age technology.
And while each mission increases our knowledge,
it also leads our imagination further and further.
How did life begin? Did it happen more than once in the universe?
The answer may lie on Mars.
ROVING MARS
Mars today is desolate, dry, and barren.
And at first glance, has little in common with our own planet.
And yet from orbit, we see what looked like dried-up lakebeds and canyons.
Clues that three or four billion years ago,
Mars may once have been wetter and more Earth-like.
And since life blossomed here on Earth, the question is:
Did it ever take place on Mars?
To answer this question, NASA's jet propulsion laboratory brought together a team
of scientists and engineers whose mission was to discover if Mars ever had
what was needed to support life.
A geologist and astronomer at Cornell University,
Steve Squyres, was chosen to lead the science team.
As principal investigator, he would direct the team's search for
life's most essential resource: water.
I've been working on the question of water on Mars for twenty-eight years.
You can't learn what you need from a telescope. You must be a geologist.
A geologist is sort of like a detective at the scene of a crime.
Um, somethin' happened here a long time ago. What happened?
Was it warm? Was it wet? Could life have existed here?
The key is in the clues and the clues are in the rocks.
On Earth, a geologist can find an interesting rock,
crack it open with a hammer, and just look at what's inside.
But we're not ready to send human geologist to Mars yet.
So we had to build a robot geologist.
And the only place this could be done was NASA's jet propulsion laboratory
where some of the most innovative engineers in the country work.
We're talking about a robot. A rover that can go to Mars,
land on the surface, take a look around, and then cut the cord and go
carrying everything it needs with it:
cameras, instruments, communications equipment. Everything.
Something that can look inside rocks and that can tell us
what clues those rocks hold.
This place, to me, is almost sacred.
This is the place where our rovers are assembled for the last time
before they leave this planet.
Everything that we do in this room must be perfect.
Over four thousand people have worked on this mission.
For every single piece of this spacecraft down to the tiniest one,
there was a person somewhere who conceived it. Who nurtured it.
Who took it from a concept to something real.
It's taken this team three years to design and build and test these rovers
and we still have work to do.
We can only launch when the two planets are properly aligned
and that's just a month away.
But we still have tests to run. We're working in shifts.
We're working almost around the clock and we don't know if we're gonna make it.
There's no one person who can really get their arms around the whole thing and say
"I understand everything about this vehicle."
It's now burst the bounds of our brains.
Well this rover is-is more than just a roving geologist.
This rover also has to be a-a spacecraft.
It actually has to fly itself from Earth to Mars.
In addition, it has to do the very subtle and quick timing control
of all the things that happen as it enters and lands the vehicle.
We had to stuff all that intelligence and capability into
that little six-wheel vehicle back there, so that it could get there safely on its own.
I call our spacecraft "The Origami Spacecraft," which means it's really
a complicated series of folds.
We've had to punch holes in the lander pedals for the wheels to snake through.
We've had to fold everything into these complicated shapes to get this system
to fit inside this tetrahedron.
It's beautiful, but at a price. And that price in this case is complexity.
There have been missions to Mars since the sixties.
There've been dozens of them. But two-thirds of those missions failed.
Mars is a spacecraft graveyard.
A spacecraft has to travel about three hundred million miles to get to Mars
at about sixty thousand miles an hour.
But it still takes seven months to get there.
Trying to hit our landing sites from that distance is like shooting a basketball
from Los Angeles to New York and having it go through the hoop without touching the rim.
The smallest mistake on our part could put the whole mission in jeopardy.
Two of the last three missions to Mars were failures.
One spacecraft burned up in the Martian atmosphere,
the other one crashed on the surface.
This time, NASA decided to send two identical spacecraft
to double our chances of success.
The two rovers are named Spirit and Opportunity.
The rovers have very different personalities.
They did even when they were babies, back when we were first building 'em.
Spirit was our troublesome first-born.
Every test we ran, it seemed that we ran on Spirit first
and the first time you try something it usually doesn't work.
So we'd run these tests on Spirit and they'd fail and we'd try to fix things
and we'd run another test and that would fail too.
By the time we got to Opportunity,
we'd learn stuff and things went much more smoothly.
The biggest problem was that we underestimated the size and weight
of the rovers. Once we realized how big they really had to be,
we also realized that the landing system we planned to use
couldn't get them to the ground in one piece.
As the rover got heavier, the lander got heavier.
As the lander got heavier, the arrow shell got heavier.
The whole thing got heavier and heavier and heavier.
From the very beginning on this mission, it seemed like nothing was going right.
The air bags are like the air bags in your car but way more expensive.
They inflate explosively around the vehicle and they cushion the landing.
The first time we tested them, they tore open and deflated.
The setbacks we knew they are going to happen.
I always tell people when you start these projects.
Uh, the same thing probably what happened to Lewis and Clark and, uh,
Captain Cook in their exploration.
Uh, what is guaranteed is that there will be setbacks.
Three...two...one.
These rovers have to land using a supersonic parachute.
The parachute design we thought would work ripped to shreds.
The lander had gotten so heavy that the chute just couldn't handle it.
We were practically out of time and all we had was a chute design
would destroy the spacecraft when we tried to land.
We had to build a whole 'nother set of new designs.
No less than three or four designs that we had to test
We were running out of money, we were running out of time.
Uh, well, I mean, the drop was successful.
Yeah.
See, uh, the fact that, uh, the parachute exploded...not a good thing.
Well, yeah, I'd rather have it happen here than any place else.
Mars.
Yeah.
That's right. Unfortunately, strictly speaking, that chute that just exploded
was the chute that we were planning on taking to Mars.
Mars is a tough place to send a spacecraft.
The average temperature is sixty degrees below zero.
It goes down to a hundred below zero at night.
There can be dust storms that darken the skies for months at a time.
But if the rovers make it, they'll give us the experience of
what it would be like to be on Mars.
We'll be able to look off into the distance and say, "Yeah. I'd like to go there,"
and then actually go and see what we find.
The rover's arm has the same dimensions as a human arm with a shoulder,
an elbow, and a wrist. The arm tucks up tight under the front of the vehicle
for when we drive around. But when we get to a rock that we want to examine,
the arm unstows and reaches out using all of its joints
to place the instruments on a rock and to begin to study them.
The hand has four fingers. One is a microscope, two are spectrometers
to tell us, in detail, what the rocks are made of.
And the fourth one is called the RAT.
The Rock Abrasion Tool.
MARS
To examine the rocks, we've got to get to them and Mars is very bumpy.
So to deal with the bumps, our engineers came up with something called a
rocker-bogie suspension system. It's a very clever design that allows each of
the six wheels to go up and over a rock independently
while the rover itself hardly tilts at all.
'Kay. Come on in, guys. Now stay clear, watch it. Watch it.
Stay clear of this thing 'cause it's gonna move in a second.
Watch! Watch the wheels. Watch the wheels. Watch the wheels. Now watch.
It goes way beyond this single mission.
See that?
The eventual goal is to send humans to Mars.
But the first person to walk on Mars is not an astronaut today.
It's someone in high school. Or in elementary school.
So it's turnin' in place, then when it gets lined up just right,
we're gonna drive it backwards.
We've invested so much work... so many years...
so much of our hopes and our dreams into these rovers.
And then when you think about where they're going,
the ride they're gonna get on that rocket, the transit through space,
what it's gonna be like when that parachute goes out
at mach two goin' through the Martian atmosphere....
You're standing next to this little robot and you realize it's gonna spend eternity on
the surface of another world. It's goin' to another planet for real.
And once they're gone, that's it. After the rovers launch,
we're never gonna see them again with our own eyes.
We've done everything we can to prepare them for the dangers they'll have to face.
But it's gonna be very hard to say goodbye.
NASA
Spirit will be launched first, then Opportunity, three weeks later.
Mars and Earth are both orbiting the sun so they're always moving
relative to each other. Every twenty-six months,
there's a brief interval when the planets are lined up just right.
At that time, and only at that time, we have enough rocket fuel to make it.
So this is our one shot.
We don't fire a rocket motor all the way to Mars.
We don't need to. We just place the spacecraft on a trajectory
to Mars and let it coast for seven months and three hundred
million miles until it reaches the planet.
Once it's been pushed on it's way to Mars by the launch vehicle
it has to, uh, maintain its orientation toward the sun and it needs to be able
to correct its orientation and direction so that it would hit Mars
and-and get to this very, very tiny, uh, spot on Mars that we're aiming for.
So all that has to take place over the course of the seven month journey.
7 MONTHS AFTER LAUNCH
SPIRIT LANDING DAY
Planning is when the real challenge begins.
Mars is so far away it takes about ten minutes for a radio signal to travel
one way between Mars and Earth. But it's only six minutes from when
you first hit the top of the Martian atmosphere to when
we're bouncing on the surface.
So there's nothing we can do to help when it's time to land.
The rovers are on their own, and we're just passive, passionately interested observers
waiting for a radio signal that shows whether or not they've survived.
Not going to be an issue. The current reported temperature is about zero degrees
Celsius which, um, is close to the limit-- the flight allowable limit.
However... Landing a spacecraft on Mars is so complicated.
There are so many things that can go wrong.
The flight computer has to know precisely the right time to deploy the parachute.
If it deploys it too high, when the parachute opens the wind forces
will just rip it to shreds.
If we deploy the parachute too low of an altitude, it won't open in time
and it will just crash right into the ground.
The trick is, every time there's some critical event:
the parachute deploys, the heat shield falls away, we change the frequency
of the radio signal.
And so Polly's sitting at her console and she's looking for these changing frequencies
and when the number changes, she knows that this event has happened.
That event has happened.
Flight director, Jason Willis, reporting that all systems are go for entry
descent and landing. We are roughly eleven minutes,
forty-eight seconds from landing at the Gusev Crater
in the southern hemisphere of Mars.
Atmospheric entry in three...two...one.
We have just passed one minute to atmospheric entry.
Current altitude: one hundred and twenty-one miles.
Current velocity: twelve thousand eighty-four miles per hour.
We are now at an altitude of seventy-three miles,
moving at a speed of twelve thousand one hundred ninety-two miles per hour.
Expected parachute deploy in five seconds. Four...three...two...one...mark.
We're awaiting confirmation the parachute has deployed.
Parachute's been detected.
Heat shield deployed event.
Uh, spacecraft reporting that heat shield has indeed jettisoned...
Spacecraft reporting lander has separated. Moving at a speed of
one hundred seventy-three miles per hour. We are near our terminal velocity.
Expected retro rocket ignition on my mark. Mark.
At this point in time, we should be on the ground.
Any signal that we receive from now indicates the vehicle would be alive,
on the ground, and bouncing.
The spacecraft has to survive all the bounces for the landing to be a success.
No signal at the moment.
Standby.
Signal strength is currently intermittent.
We don't see a signal at the moment.
Right. We saw an intermittent signal that indicated we were bouncing
however...however, we currently do not have signal from the spacecraft.
Okay. Please stand by.
This time, we're approximately ten minutes after landing.
The vehicle should have rolled to a stop by now.
The deep space network stations at Goldstone and Canberra are still searching for the signal.
They see it.
What do we see?
We've got the signal!
The first thing we have to do after we land is open our solar panels
to the sun so we'll have some power. This charges up the batteries.
After that, we can deploy the camera mast so the rover can see
and deploy the antenna so the rover can talk to us.
Our first pictures from Mars!
Look at that! That's looking down on our vehicle.
We could not have imaged returns as early as this, as clear as this,
as successful as this, and in the volume that it has been.
Uh, ladies and gentlemen, Mars.
We sent Spirit to Gusev Crater, a crater in the southern highlands of Mars.
It's a hundred miles in diameter.
What makes it special is that emptying into it is a giant watercarved channel.
So Gusev is a hole in the ground with a dry river flowing into it.
There has to have been a lake in this crater once upon a time.
We sent Spirit there to seek out sediments.
To look for sedimentary rocks that were laid down long ago in that lake.
Once we landed, I think the scariest part of the whole mission
was the initial unfolding of the rover.
There are so many gears and springs and motors and hinges and latches
that have to work just right or you're done.
Once everything's deployed, we're ready to start lookin' around.
We can look off into the distance with our cameras and with our infrared spectrometer,
and we can learn a lot from a distance of fifty yards, a hundred yards about what the
look like and what they're made of. Then, if we see a rock that has a texture or
a composition that looks interesting to us, we can drive over to it
and check it out in detail.
For driving, the rover has these kinda googly-eyed cameras that it uses
to take images of the terrain in front of it. They've got wide-angle lenses
and they provide sort of a fish-eye view. Spirit uses these pictures to
make it's own decisions about how to drive.
It'll drive forward and then take a look at a rock and say,
"That's too big, I have to go around that." Or, maybe it'll see smooth sailing
and just move on.
But we can actually program different levels of courage or cowardice
into the rover, telling it how aggressive it should be depending on how dangerous
we think the terrain is.
These rovers are so complicated, that it takes hours to get a set of commands right.
So when we operate 'em, we'll normally send commands to them just once a day.
The first rock that we looked at was this one. We named it Adirondack.
When a rock sits on the surface of a planet, it can undergo what's called 'weathering.'
When it's exposed to sunlight or humidity or wind, the surface of the rock
can be modified and the evidence of how it formed can be destroyed.
So to get to the clues you need, you have to get inside the rock
below the weathered surface.
The key to understanding Adirondack was the rock abrasion tool.
The RAT gives us the ability to grind into a rock, exposing the unaltered
evidence inside.
So we put a RAT hole into Adirondack and then we hit it with everything we had.
We looked at it with our cameras, we looked at it with our spectrometers,
we looked at it with our microscope. Adirondack is a piece of lava.
It's not a sedimentary rock. And every other rock around it
is a piece of lava too. This was a huge disappointment.
We came to Gusev Crater looking for sediments that were laid down
long ago in a lake, but what we found was lava. Volcanic rock.
The sedimentary rock must be there but it's been buried under the lava
and we couldn't get to it.
When we realized that we hadn't landed on the stuff we came for,
we decided we had to go some place else. A mile and a half away,
there's this spectacular range of hills called the Columbia Hills.
You gotta remember that Spirit was designed to go only six hundred yards
over its lifetime.
So we set out for those hills not knowin' if we'd ever make it.
Meanwhile, on the other side of Mars, Opportunity was about to land.
When Opportunity landed at Eagle Crater,
it was a three-hundred million mile interplanetary hole-in-one.
We rolled to a stop right in front of layered bedrock.
Bedrock is geologic truth. Opportunity landed in front of a Martian history book.
When we drove off the lander and looked at the soil in front of us,
we saw that it was littered with what looked like little round beads.
An uncountable number of little round things.
We took out our microscope, we reached out,
and looked at the soil in detail and the picture that came down was astounding.
They were perfect spheres. I will remember for the rest of my life
how I felt when I saw that first picture.
When we got to the outcrop and looked at it up close, we realized
that the spheres are embedded in the rock, like blueberries in a muffin.
The rock erodes away and the blueberries fall out.
And roll down into the soil.
The blueberries, it turns out, are made of hematite,
a mineral that on Earth is often formed in liquid water.
Next, we found jarosite, which is a mineral that couldn't have formed
unless there had been water in the rocks. So there was water underground here.
Our most extraordinary discovery came when we found ripples in the rocks.
Ancient ripples that formed when water flowed over sand on Mars
billions of years ago.
So there wasn't just water underground here... there was water at the surface.
Opportunity discovered that at this place billions of years ago,
Mars was most likely a habitable world.
It was a place that, for some interval of time, was suitable for some forms of life.
Decades of work paid off with this discovery.
Billions of years ago there were shallow, occasional pools of water.
Don't think an ocean, think of salt flats.
And the water may not have been a pretty blue.
In fact, it may have been so acid it dissolved iron out of the rocks
and made wine-red pools under a pink Martian sky.
All the discoveries that Opportunity made about water
happened in the first six weeks of the mission. Everything went right for that rover.
I call Opportunity "Little Miss Perfect".
Opportunity lands in this place where the evidence is right there.
The driving is like a parking lot. Everything is perfect.
Spirit, our kinda tough hard-working blue collar rover lands
in this awful, rocky, rugged place on a lava plane a mile and a half from
the nearest interesting rocks and has to struggle for five months
just to begin her mission.
Spirit had to work for everything, literally had to climb a mountain on Mars.
We use the power that comes from the sun to operate the vehicle
and to charge the batteries. So the solar arrays are essential.
On the way to the Columbia Hills, Spirit's solar rays were getting coated with dust.
We were getting to the point where Spirit was simply gonna die.
Then, one wonderful day we, climbed up onto the crest of a ridge where
we were hit by not one but several gusts of wind that just cleaned the solar arrays off.
It was like having a brand new rover. Spirit got high up in the Columbia Hills
and started to find stuff that was different from anything we'd seen.
There were salt deposits in the hills and there were rocks
that clearly had been altered by water. It took months of work and struggle
but Spirit finally showed us there had been water on both sides of the planet.
She gave us exactly what we needed.
These rovers were designed to last only ninety Mars days
and they've already done many times that. They've developed personalities.
They're work horses. They say, "Push us. Ask us to do more.
We can go further, we can go faster." So we asked so much more
than they were ever intended to. And to our amazement, they'd do it.
We don't know what will kill these rovers; they do get old, motors break,
lubrication goes away in the motors, the wheels may stop turning.
We have no idea what will happen.
But they're not gonna last forever. And as the dust keeps falling,
the solar arrays keep getting dirty.
What could happen, with time, is some day we won't be able
to charge the batteries enough to keep the rover warm at night.
And if that happens, the rover's going to get too cold.
And one morning, it just won't wake up.
Spirit and Opportunity have shown us that once, three to four billion years ago,
Mars had the essential ingredients for life. So the next step is to seek out evidence
of life itself. Right now, we have one example of life. Us.
We may be all there is. We simply don't know.
But if you can show that life developed twice in one solar system
and then you considere the multitude of solar systems out there,
it takes no great leap of imagination to believe that
life might be a common phenomenon throughout the universe.
Our rovers have gone farther, harder, and longer than even we, their creators,
believed possible. They've done heroic work.
But some day we won't need robots.
Some day, there'll be humans on the surface of Mars and boot prints in our wheel tracks.
This mission has put us on a great trajectory to learn
more about Mars and about ourselves.
But right now, Spirit and Opportunity are still roving Mars.
It's not just that they've exceeded our wildest dreams.
In many ways, they are our wildest dreams.
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