NARRATOR: When Spirit and Opportunity hit Mars in 2004,
they weren't expected to last long.
MAN: You never know when these things are going to drop dead.
We don't know! We have no way of knowing!
NARRATOR: That was almost 12 years ago,
and it's not over yet.
MAN: Betting against the rovers is a good way to lose money.
I don't do it.
NARRATOR: A three-month sprint turned into a Martian marathon,
one of the great journeys of the Space Age,
and one of the most surprising.
MAN: Oh, my God!
There wasn't a single one of us who expected what we found.
Anybody who tells you so is lying.
¶ ¶
NARRATOR: They've seen the sun rise thousands of times on Mars,
150 million miles from home.
Every day, as one woke up and went to work,
on the opposite side of the planet
the other shut down for the night.
Spirit and Opportunity defied all expectations.
They were designed to spend three months
driving less than half a mile over smooth, flat ground.
MAN: I was pretty optimistic.
I thought they were going to go for six months.
NARRATOR: Instead, Spirit lasted six years,
and Opportunity is still going, 12 years and 26 miles later.
They scaled mountains and crater walls,
survived dust storms, radiation, and broken wheels,
and they became almost human to the people who work with them.
SCOTT MAXWELL: We feel so close to these vehicles.
They are our bodies, they are the way that we go to Mars,
and we're people who grew up dreaming about the possibility
that one day we might walk on other worlds.
They've made it possible for us.
STEVE SQUYRES: I think the thing
that draws people to them the most
is the way that they experience this adventure.
They get into trouble, you know, and bad things happen to them,
and then they, they manage to get out of trouble
and keep going, or, or they don't.
NARRATOR: Martian days are called sols,
and September 23, 2008,
was sol number 1659 for Opportunity.
Already five years past her warranty,
she set off for Endeavour Crater,
a seven-mile journey across a desolate plain
that would take more than three years.
On the other side of the planet, her twin had fewer options.
Coated with dust and starved for power,
Spirit had to park on a steep bank
with solar panels angled toward the sun to survive the winter.
¶ ¶
By now, both rovers had cheated death so many times,
most people had given up trying to predict
how much longer they would last.
SQUYRES: You know, at this point, every day is a gift.
We just push the vehicles as hard as we can.
Um, enjoy them while we got them.
And someday they're going to die, and I don't know when.
NARRATOR: It takes Mars two Earth years to orbit the sun,
so Martian seasons are twice as long.
Spirit had been parked almost 300 sols
by the time summer returned.
Even dirtier now, her solar panels produced a fraction
of the power they once did.
But it was time to move.
She was parked on the north bank of a low mesa called Home Plate.
The scientists wanted to explore the area to the south.
It was the rover drivers at NASA's Jet Propulsion Lab
who had to get her there.
Over the years they'd learned to cope
with Spirit's biggest handicap--
a front wheel that seized up earlier in the mission.
Ever since, they'd been driving backwards,
dragging it through the dirt.
MAXWELL: You know when you go to the grocery store
and you get the shopping cart with the one stuck wheel,
and you're trying to get that down the aisle?
Driving Spirit at this point is a lot like trying to do that,
only your shopping cart is 300 million miles away,
and you have to drive it with a keyboard.
NARRATOR: The shortest route to their destination
was straight across Home Plate.
But with the dead wheel, Spirit couldn't climb the bank.
They tried going down the east side,
but ran into soft ground and had to turn back.
The drivers had to settle for the long way around,
through unknown terrain.
SQUYRES: The rovers' safety depends on those guys
doing their job right.
Okay, the person who's running the PanCam camera
is not going to drive the rover off the cliff
or get it stuck in a sand dune.
That's the rover drivers.
NARRATOR: On sol 1886,
they were driving south along the west side of Home Plate.
ASHLEY STROUPE: It looked the same as terrain
we had driven over hundreds of times before.
NARRATOR: But Mars can be deceptive.
What looked like solid ground
was just a thin crust that gave way.
STROUPE: And the wheels started spinning
in this very fluffy, soft stuff,
and we just couldn't get any traction.
MAXWELL: We're driving a wounded vehicle
through very treacherous terrain, and we knew it.
This is the kind of trap that we knew might be out there
waiting for us.
That's why we didn't want to go down there in the first place.
But it was the only way to get where we wanted to go.
NARRATOR: Trying to escape, they dug in deeper,
and things got worse.
STROUPE: One day we were looking carefully at the terrain models
when we discovered that there was a rock
underneath the vehicle.
MAXWELL: This is pretty much your nightmare scenario
for this rover design,
because you can get to a point
where you're kind of hung up on something,
and all your wheels are kind of flailing,
and you're unable to ever touch the ground.
NARRATOR: 100 million miles away, stuck in a dust bowl,
possibly hung up on a rock, with one dead wheel.
Life on Mars had always been more of a struggle
for Spirit than Opportunity.
Opportunity got off to a quick start back in January 2004,
touching down near the equator
in a place called Meridiani Planum.
¶ ¶
By chance, her airbag rolled into a shallow crater.
¶ ¶
At JPL they waited for the first pictures.
¶ ¶
[cheering]
MAN: Look at this!
SQUYRES: We open our eyes and there's this astounding outcrop
of layered bedrock right in front of the vehicle.
That outcrop in the distance is just is out of this world.
I can't wait to get there.
[laughter]
NARRATOR: Bedrock was exactly what they came looking for--
a geological key to the history of Mars--
and possible clues to whether it was ever a place
that could have supported life.
The search for extraterrestrial life begins with liquid water,
a basic necessity of life on Earth.
Mars has been a freeze-dried desert for billions of years,
but the surface is scarred
with ancient river channels and deltas.
From orbit, though, it's hard to tell exactly what was going on.
SQUYRES: How much water was there?
What was its chemistry?
Suppose you were a microbe,
would you have liked that place or not?
If so, why?
NARRATOR: The rovers are designed to decode the story
of early Mars preserved in the rocks and minerals.
Each has a toolkit of instruments on its arm
to analyze what they're made of.
They see the world in three dimensions
with four pairs of stereo cameras.
There's a high resolution PanCam for color panoramas,
stitched together from individual frames.
Filters reveal details invisible to human eyes,
and a spectrometer scans for minerals
that may have formed in water.
They have wide-angle, black-and-white stereovision
for navigation and planning.
And below the deck,
fisheye cameras see the world at ground level,
looking backward and forward.
¶ ¶
Opportunity soon made some startling discoveries.
SQUYRES: It was like being inside
this bizarre Martian mystery novel,
where every sol or two you get a new clue handed to you.
NARRATOR: First, tiny spheres the size of BBs,
littering the ground and embedded in the rock
like blueberries in a muffin.
SQUYRES: It was such a surprise.
I mean, what the heck were those things?
NARRATOR: They turned out to be an iron mineral called hematite.
On Earth it forms spheres like these in water-soaked rocks.
¶ ¶
Then came sulfur-rich minerals
that can only form in wet ground.
And finally, petrified ripples created by flowing water,
frozen in time as sand turned to stone.
It all pointed to a time billions of years ago
when salty, acidic water soaked the ground
and sometimes flowed across the surface.
SQUYRES: It was a new Mars!
We were giddy, we were incredulous,
we were sleep deprived beyond words.
It was so tiring.
But we were just running on adrenaline, you know.
And it was just so much fun.
It was the most fun I've ever had as a scientist.
It was just fabulous.
NARRATOR: In just three months,
Opportunity accomplished everything
the scientists had hoped for,
and set off to explore another crater.
On the other side of Mars, though,
things were not going so well.
Spirit landed three weeks ahead of Opportunity in Gusev Crater,
a hundred-mile diameter basin
that looked like an ancient, dried-up lakebed.
But on the ground she found nothing but volcanic rock.
SQUYRES: I wouldn't have wanted to admit it at the time,
but the Spirit landing site
initially was a crushing disappointment.
We went there looking for layered sedimentary rocks
laid down billions of years ago in a Martian lake,
and instead we got lava as far as the eye could see.
And every damn rock was like every other damn rock.
They were just all the same.
And the Spirit team got a little disheartened after a while.
NARRATOR: But eventually they embraced the role
of the underdog.
SQUYRES: People just got emotionally attached
to their rover.
You know, I'd tell them, well, you can switch to Opportunity,
and they'd say, 'No, no, I'm not gonna.'
Because they had gotten their heart set on Spirit succeeding.
MAXWELL: Opportunity was certainly the lucky rover.
But for me, I worked on Spirit, and Spirit is my favorite rover,
because Spirit had to work for everything
she ever got in her life.
NARRATOR: Squyres knew that Spirit had to move.
The hills on the horizon, a mile and a half away,
looked like the only chance to salvage the mission,
but it was four times farther
than the rover was designed to drive,
and the engineers were skeptical.
ROB MANNING: I remember he said that.
'This is where we're going.'
What do you mean, you're going to drive up on those hills?
This is going to be a lot more than 90 days!
Good luck.
We're probably going to die on the way there.
He said, 'No, we're going to go.'
I said, 'Okay. You're driving. You've got the keys. Good luck.'
SQUYRES: We're 100 sols into our 90-sol mission.
The warranty has expired.
Our only chance of getting to something new
was to push the vehicle beyond anything
it had ever been designed to handle.
Otherwise it was gonna be just lava
until the end of the mission.
NARRATOR: While Spirit trekked to the hills,
Opportunity pulled up to the rim of Endurance Crater.
The exposed bedrock in the walls offered a chance
to look farther back in Martian history.
SQUYRES: Oh, my God!
NARRATOR: The rovers weren't designed
to scramble in and out of craters.
But the science down below was too tempting to pass up.
SQUYRES: We all wanted to go in.
I mean, we're standing on the lip
of the most magnificent thing anyone's ever seen on Mars,
with a rover that we all believe in our hearts can do it.
NARRATOR: First, they had to prove to themselves
and to NASA that Opportunity could get in and out
of the crater safely.
SQUYRES: And in fact, the thing climbed beautifully.
I was stunned by how well this thing could climb
steep, steep slopes, as long as they were rocky.
30, 32 degrees, boop, boop, boop, boop,
right up it, it was amazing.
NARRATOR: In June 2004,
Opportunity took the plunge into Endurance Crater.
¶ ¶
By now, Spirit had been slogging for eight weeks
to the base of the Columbia Hills.
There might be a payoff on the upper slopes.
But getting there would be a monumental challenge.
¶ ¶
Spirit's solar panels, her only source of energy,
were getting dusty
and producing just half as much power as they used to.
And she was about to face her first winter on Mars.
SQUYRES: The seasons were changing.
Spirit is in the southern hemisphere of Mars.
And what that means is in the winter
the sun is going to go low in the northern sky.
And it's going to get lower and lower and lower.
And as it gets lower, the amount of power that we're going to get
from solar arrays is going to get less and less and less,
unless we can do something.
NARRATOR: It would help if they could tilt the solar panels
toward the sun to get more power.
SQUYRES: Well, we didn't build a tilt mechanism into the rover.
The only way to tilt them towards the sun
is to tilt the whole rover towards the sun.
But the beauty of it was, now we had a hill.
NARRATOR: If they followed a route that kept the rover
tilted toward the sun,
Spirit might be able to survive the winter
and climb the mountain at the same time.
SQUYRES: It started to dawn on us
that we maybe had more life in this thing than we had thought.
¶ ¶
NARRATOR: Opportunity spent that first winter on a sunny slope
inside Endurance Crater.
Sampling rocks from the crater wall added greater depth of time
to the story found at the landing site.
The water that soaked this ground lasted millions of years.
¶ ¶
Another score for Opportunity,
and time again to move on to something new.
¶ ¶
It's a long way from Endurance Crater
to anything dramatically different.
The most tempting target was four miles to the south.
A huge impact crater called Victoria.
Deeper than Endurance,
it was a chance to look even farther back in time.
JOHN CALLAS: We thought, wow, could we get there?
Six kilometers to the south--
remember, that's six times the designed distance capability
of the rover.
NARRATOR: But it looked like easy driving most of the way,
so they decided to try.
MAXWELL: They basically handed us the keys and said, alright,
you've got this big parking lot from here to there.
Go for it.
NARRATOR: 21 months later,
Opportunity pulled up to the rim of Victoria Crater.
She would spend the next two years finding her way
in and out of this basin,
adding even more detail to the water history of Meridiani.
¶ ¶
Meanwhile, Spirit had been climbing the Columbia Hills
for almost a year.
Her solar panels were so dusty
she could barely generate enough power to get through the night.
But then she got lucky.
The windy season had arrived.
One day a random gust hit the panels and wiped them clean.
Spirit sent back this picture of her deck
just before the cleanup,
and this one just after.
SQUYRES: It's a new lease on life.
We've got more power than we can use.
I mean, we have to shut the vehicle down
during the afternoon to keep it from overheating.
It's producing so much power.
It was, it was just astonishing.
NARRATOR: Spirit now had a shot at reaching the summit.
¶ ¶
There was good reason to try, and not just for science.
This was a chance to accomplish something
no explorer had ever done before--
the first ascent of a mountain on another planet.
¶ ¶
NARRATOR: In September 2005,
after more than a year of climbing,
Spirit reached the summit of Husband Hill.
MAXWELL: She stands there at the top of that hill
that she's conquered now on another planet,
and she looks at the whole world around her.
I love her for bringing us that.
SQUYRES: More than anything else I think I felt,
gosh, aren't we lucky to do what we do?
You know, we just climbed a mountain on Mars!
Damn!
¶ ¶
NARRATOR: Four years later,
Spirit's triumph on Husband Hill was a distant memory.
At JPL they were working on a plan
for getting her out of the trap she'd fallen into at Troy.
They came up with a mixture of powdery soil and sand
similar to the stuff Spirit was buried in.
Then they brought in the rover that stayed home--
a nearly identical sibling used for testing on Earth.
With the box tilted at 12 degrees,
replicating the slope,
they carefully reproduced Spirit's position at Troy.
They would not send another drive command to Mars
until they were sure they had a plan that could work.
MAXWELL: When we test getting out,
we don't want to do anything
that would harm the real vehicle.
The real vehicle is a one-of-a-kind,
a priceless resource, and if we're in this kind of trouble,
we want to do all the testing we possibly can with a vehicle
that we can pick up and move if we have to.
NARRATOR: It was a method devised years earlier
for another rescue operation.
¶ ¶
Opportunity ran into trouble
on what should have been an easy drive to Victoria Crater.
CALLAS: It was just these gentle, sloping dunes
literally all the way to the horizon.
There wasn't a rock or a hazard to be seen anywhere.
And we figured, oh, gosh,
you could drive blind in this area, it was so safe.
SQUYRES: We were using a driving technique
that I think could be charitably described
as bombing along at top speed with our eyes closed.
MAN: Mobility.
WOMAN: Go ahead, Mobility.
MAN: Up on screen number three is the trajectory...
NARRATOR: On sol 446, things suddenly came to a halt.
Pictures from the previous sol popped up in mission control,
and Opportunity's wheels were buried to the hubs in deep sand.
SQUYRES: The wheels broke through the surface,
and we did 50 meters' worth of wheel turns,
thinking we were happily progressing
across the Meridiani Planum surface,
and instead we were just digging slowly down and down
into this, into the sand.
MAN: Wheels look like they're about 80%
under the ground there.
NARRATOR: It took some time to figure out the next step.
SQUYRES: The first rule in a situation like that
is don't do anything dumb.
MAN: It literally didn't make much more progress
after about this point.
SQUYRES: We shouldn't have gotten into this mess
in the first place,
but let's not make it worse
by, by guessing how to get out of it.
NARRATOR: They built a Martian sand trap,
brought in the third sibling,
and began experimenting with techniques to escape.
The best approach, they discovered,
was to put it in reverse and gun it.
For a rover, though, gunning it happens in slow motion.
SQUYRES: We had to do 192 meters' worth of wheel turns
on Mars to get the vehicle to move one meter.
It took days and days and days.
And you know, you'd do four meters,
eight meters' worth of turns,
and you'd come in the next morning, and it went that far.
NARRATOR: On sol 484 Opportunity finally broke free of the trap.
It seemed bad at the time,
but Opportunity's ordeal in that dune at Meridiani
was a minor speed bump
compared to Spirit's situation years later at Troy.
The rock underneath was a big concern,
so they used the close-up camera on the end of the arm
to get a look at it.
The camera's not designed to focus
beyond two and a half inches,
but it was the only way to see the under the rover.
Even then, they couldn't tell if they were looking
at a piece of bedrock that could impale the rover
or just a loose stone, or even if they were in contact with it.
It was clear, though, that if they sunk any deeper in the pit,
they would be.
And they did sink deeper every time they turned the wheels.
There was no obvious way out, and it took a toll.
CALLAS: Well, there is a lot of stress.
People are having a hard time, we all are.
If the rover is permanently stuck, that is a big deal.
NARRATOR: Two years before Spirit bogged down at Troy,
Mars delivered a punishing blow
that nearly killed Opportunity...
A massive dust storm on a scale
that happens just once every three Martian years.
SQUYRES: Our first summer on Mars it didn't happen.
And our second summer on Mars it didn't happen.
But our third summer on Mars it happened.
And it blew up into a global storm,
blanketed the entire planet.
From where Opportunity sat on Meridiani Planum,
you looked up and you couldn't tell
where the sun was in the sky.
The amount of direct sunlight
that was reaching the solar panels
was less than 1% of what it is on a clear day.
NARRATOR: At JPL they shut down
all but the most essential systems on the rover
to conserve power.
CALLAS: They were never designed to survive a dust storm.
The rovers are solar-powered.
They need the sunlight to survive.
So each day we would turn things off
reducing the amount of power.
But you know, you can't turn everything off,
because it's all about keeping the rover warm.
SQUYRES: One of the things that keeps the vehicle warm
is running the computer inside.
And so there was this delicate balancing act
between running the computer enough to keep it warm,
but not running it so much
that you draw the batteries down too much.
And we were just right on the edge of catastrophe.
NARRATOR: On the other side of Mars, the dust was not as heavy,
and Spirit had fewer problems.
But at Victoria Crater,
Opportunity was in serious trouble.
The engineers had done all they could,
and now they had to wait.
JAKE MATIJEVIC: It's like sitting at someone's deathbed,
you know, and waiting and waiting and wondering,
well, is it, is it going to survive,
is it going to come back?
Is it going to be able to talk to us, alright?
And it was very agonizing.
It got to the point where you couldn't even take measurements
to figure out how bad it was.
All you could do is just sort of sit there.
We just ran out of things to try.
NARRATOR: Soon the power would be so depleted
that the rover would simply shut itself down
until it could recharge its batteries.
And with no power it could freeze to death.
MAXWELL: You kind of don't want them to go out like that.
You know, you don't want them to struggle and persevere
and just sort of get killed by a blanket of dust.
It almost just doesn't feel right.
¶ ¶
NARRATOR: Just when everyone had given up hope,
the sky began to clear,
and the six-week ordeal finally came to an end.
A gust of wind cleared Opportunity's solar panels,
and she went back to work.
¶ ¶
Two years later, Spirit was still stuck on Mars,
and so far, all attempts at JPL
to come up with a solution had failed.
CALLAS: If there's a way of getting the rover out,
we're going to find it.
It is, however, a very, very difficult situation.
NARRATOR: The biggest problem was the dead wheel--
the only one on solid ground, yet unable to help.
It had been Spirit's Achilles' heel
since it failed years before.
It happened soon after Spirit's triumph in the Columbia Hills.
She needed a solar-friendly hillside
to spend the next winter,
and from the summit they spotted a good one
just beyond a low mesa they called Home Plate.
SQUYRES: It was an obvious target to try to get to,
but it was a long way off.
NARRATOR: The seasons would soon be changing again,
and Spirit needed to reach that hillside before winter.
¶ ¶
A hundred sols later, Spirit was just 300 yards
from the winter refuge on McCool Hill.
SQUYRES: What happened, though, was the right front wheel quit.
The right front wheel just stopped turning.
That came at a really bad time,
because we were trying to get onto the slopes
of McCool Hill,
and without that wheel functioning properly,
we can't climb.
NARRATOR: At JPL, they experimented
with 5-wheel driving techniques.
They found it easier to drive backwards,
dragging the dead wheel.
But it tended to pull the rover off course,
complicating the drives.
CHRIS LEGER: Each day we only had an hour
to an hour and a half of power,
and we had to write these incredibly complicated sequences
of, you know, sometimes 400 commands
just to try to drive five meters.
MAXWELL: We were really in a race against the clock,
because we had something like three weeks
before Spirit just wasn't going to have enough energy
to survive the night.
And people were talking about her
like she was the walking dead.
SQUYRES: We're learning to drive all over again.
The seasons are changing.
The power is getting less and less daily.
Everybody's starting to get nervous, and then we get stuck.
CALLAS: We got into this, it was kind of like quicksand,
and we couldn't get out of it.
So we were thinking, oh, my God, are we going to be stuck here,
and is the rover going to die here?
NARRATOR: Eventually they got Spirit free,
but by then it was too late to reach McCool Hill.
SQUYRES: Forget about this stuff hundreds of meters away.
We're never going to make it.
What do we got that's next to us?
NARRATOR: They settled for a spot nearby
where they could get at least a minimal tilt toward the sun.
SQUYRES: And that was it.
And there we sat for seven months.
But we survived.
NARRATOR: That was the first time Spirit got stuck,
and the first time she had to sit out the winter season.
NARRATOR: After sitting out that first winter,
Spirit started driving again,
and they soon discovered that dragging a dead wheel,
digging a trench, wasn't all bad.
SQUYRES: We're driving along one day in this little valley,
we look at the pictures of the trench that were dug that day,
and there's this one spot
where the soil is practically as bright as white snow.
That got our attention.
NARRATOR: They'd seen bright soil in the tracks before,
but nothing like this.
SQUYRES: It turns out this stuff is more than 90% pure silica.
Not quartz, it's not beach sand.
This is amorphous silica.
It's like opal.
All of a sudden we realize we've just come across something
completely new and different that we had never seen before.
NARRATOR: On Earth, this kind of silica forms in hot springs
or volcanic steam vents.
SQUYRES: And the thing that's cool about that
is you can go to hydrothermal systems on Earth,
and they're teeming with microbial life.
And that makes it a pretty important place.
NARRATOR: It was the biggest discovery of Spirit's mission,
and it would not have happened without the broken wheel.
Four years later in early 2011,
Opportunity was still slogging across the plains of Meridiani,
headed for Endeavour Crater.
She was spotted from orbit at the rim of a small crater
called Santa Maria, 17 miles from her original landing site.
Endeavour was still four miles away.
It could take another year to get there.
MANNING: I think some of the most haunting images
from the rovers has got to be Opportunity's look backwards
toward the place we had come from.
There's this sense of vastness of Mars,
the sense of being a long way from home.
This poor rover is by itself, so far from where it had come,
and yet had so far to go to its next destination,
with peril along the way.
NARRATOR: Spirit was still stuck in the dust pit called Troy,
and her situation was getting desperate.
Dust was piling up on the solar panels,
and another winter was approaching.
STROUPE: We were running out of time.
After all of our testing, we came up with a plan
that we thought would work,
and we were ready to try it out on Mars.
NARRATOR: They planned to back out with a turn
that might help the rover clear the rock,
but they soon hit another snag.
MAXWELL: What makes this so frustrating
is that just after we started implementing the plan,
another wheel failed,
so now instead of a vehicle with five wheels,
and one anchor stuck in the sand,
we have four wheels, and two anchors, and less time;
no time to, like, stand down and do anything about it,
so we really had to just
completely fly by the seat of our pants.
NARRATOR: A view of one spinning wheel from a rover camera
inspired a new strategy.
STROUPE: Somebody likened our condition
to having to swim through a fluid.
And we thought about that, and the strategy we came up with
was kind of using the wheels, steering them back and forth
in kind of a breaststroke maneuver,
trying to sort of swim our way through this material.
And sure enough, it started working.
And we were making really good progress.
In fact, we got to the point
where that rock that was underneath us
that we were so worried about
appeared in the front hazard camera.
And we were off that rock.
NARRATOR: It seemed like they had a chance, but time ran out.
MAXWELL: The part of it that really breaks my heart
is that we were making progress.
We just needed a little more time, and we would have done it.
Um, but we had winter coming on,
and we just ran down to the point
where we didn't have power to drive anymore.
NARRATOR: In March 2010,
Spirit did not call home for a scheduled communication session.
No longer able to capture enough solar energy
to wake up in the morning,
the rover likely went into hibernation mode--
no survival heaters, no power to communicate--
something she'd never dealt with before.
MAXWELL: Even then, we still had a lot of hope for her,
and we still believed that she was going to come out of it.
NARRATOR: With some luck she would wake up again
when summer returned and the sun was higher in the sky.
But on winter nights
the temperature can plunge to 150 below zero--
a metal-stressing shock that can damage electronics
and kill an old rover in any number of ways.
NARRATOR: In September 2010,
Martian spring was returning to Gusev Crater, and with it,
the possibility that Spirit would wake up and call home.
BEN MILLER: Copy 26.
Let's see if we can get a signal here. Over.
NARRATOR: JPL controllers monitored the rover's frequency
on the Deep Space Network,
but heard nothing.
STROUPE: So our hopes that she would just come back online
and wake up and phone home, that didn't pan out.
It could be something as simple as the main antenna
is not working and that we could possibly regain contact
through another path,
or it could be that she's just not awake.
NARRATOR: In April 2011 they began a final, all-out effort
to make contact.
MILLER: The command is radiating.
It will take four and a half minutes,
and then once that's done, we'll repeat this five more times.
CALLAS: We're involved in a very extensive recovery effort,
building and sending commands to the rover
in the hope of eliciting some sort of response.
MAN ON RADIO: There's a possible signal we're trying to acquire.
MILLER: Copy that. When you get a chance, let me know the time.
Hey, John, we...
MAN ON RADIO: 220212.
MILLER: Copy, 220212, possible signal.
He hasn't locked on it.
CALLAS: Okay.
MILLER: If he locks on it, I'll print that out.
Yesterday we did lock on one.
STROUPE: Spirit had pulled things out of the fire
so many times, I don't think anybody truly believed
that she wouldn't get out of this one, too.
NARRATOR: Not this time.
Another false alarm.
In May 2011, they were down to their final attempt.
MILLER: So, cross your fingers, cross all of 'em.
CALLAS: People are holding out hope,
but I think the reality is,
is people have to start to accept
that Spirit's time on Mars may be done.
NARRATOR: Spirit never did call home.
There was no way of knowing for sure if she was dead or alive,
but NASA declared that the mission was over in June 2011.
SQUYRES: You'd like to think at that point,
well, you turn it off.
Well, we can't turn them off.
They don't have an off switch.
Um, if you build a piece of hardware with an off switch,
you might accidentally hit that off switch
when you don't mean to, and you don't want to do that.
So we have no way to turn them off.
There's not a command that you can send
that says, okay, you're done.
It will obediently sit there
listening for commands from Earth every day
as long as it's alive and able to do so,
just waiting for its next set of instructions.
You can't turn the things off.
You can't do it.
NARRATOR: Today, Spirit can be seen from orbit
sitting next to Home Plate--
a hard-fought five miles from her landing site
on the far side of the Columbia Hills.
¶ ¶
MAXWELL: She lived a great life.
You know, we sent her to a nasty, unforgiving hellhole,
and she did a great job.
SQUYRES: They've been through so much.
You know, I mean, the perils that they have been through
and that we've kind of suffered through with them,
it's like any kind of relationship with somebody.
As you go through many things over the years,
the relationship deepens.
NARRATOR: Still rolling,
Opportunity passed the 26-mile mark, a full Martian marathon,
on sol 3968,
and is now working her way along the rim of Endeavour Crater--
a place so different from where she landed,
it's like a new mission.
14 miles across,
the crater dwarfs anything she's seen before,
and the rocks along the rim tell a very different story.
SQUYRES: There wasn't a single one of us
who expected what we found.
Anybody who tells you so is lying.
NARRATOR: Instead of rocks laid down in water
as harsh as sulfuric acid,
here she's found clay minerals that formed in freshwater--
a much friendlier environment for life.
SQUYRES: I used to have this naive idea that at some point
we'd be able to sit back and fold our arms
and say, yeah, well, we did it.
You know, we've learned everything we can about Mars
at these places with these rovers.
I don't think that's going to happen.
NARRATOR: And when Opportunity falls silent, too,
she and Spirit will stand on Mars virtually forever
amongst the earliest pioneers of the Space Age.
SQUYRES: It's cold, it's dry, there's no vegetation.
They're not going to rust or anything like that like.
You know, these things could be still sitting there
with their aluminum surfaces
shining a million years from now.
They're going to last a long, long time.
Longer than most things that humans have ever built.