- [Narrator] Ask someone to draw a picture of a planet,
and odds are it will be this one.
It is the sixth planet out from the sun
and the second-largest in our solar system.
It is, of course, Saturn,
a world encircled not only in majestic rings
but in an array of moons that have been likened
to a solar system in miniature.
(rocket boosters roaring)
In 1997, an international mission was launched to Saturn
that would, for the first time,
attempt to place an orbiting spacecraft around the planet
and land a probe on a moon in the outer solar system.
But this was a mission that had to
fight its way to the launch pad.
- [Lew] We're going to have to operate
under a very strict fund ceiling,
one that is imposed by Congress.
- [Casini] This will require doing business
in a drastically different way than we've done before.
- [Bob] It took a lotta time, a lotta negotiating,
a lot of compromises to make that work.
- [Julie] The first time I saw the spacecraft together
when we stacked without the blankets, we were just,
we were without words standing out there.
- [Narrator] The journey to Saturn
would take seven long years,
but the success, or failure, of being captured into orbit
depended on what would happen during just three hours.
- [Charles] The engine better fire,
otherwise we'll end with a flyby.
- Copy.
DCS Fault Protection.
- [Linda] I think as a ring scientist,
my greatest concern was really crossing
through that gap in the F and G rings.
It would only have taken one marble sized particle
in the wrong place in the spacecraft
to perhaps have ended the mission.
- [Man] So I would lie in bed at night and think about
what other tests should we do?
What other question should I be asking?
What should we be poking out here that we haven't done yet?
- [Julie] We chased everything that could go wrong
down the rabbit hole.
We went down every path of, if this goes wrong,
what do we do?
If that goes wrong, what do we do?
- [Earl] And this was one of those moments
where you're either in orbit
or you're a billion dollar flyby.
- [Todd] Closest approach is just a little over
two minutes away.
Predicted temps today, -226 degrees Fahrenheit,
winds of 1100 miles per hour.
Hurricanes the size of the Earth.
Cassini would do well to batten down the hatches.
- [Narrator] Saturn was once but a single
bright point of light in the night sky,
but in 1610 Galileo peered through his telescope
and saw something else.
On either side of the planet,
he thought there might be moons.
Two years later, Galileo looked again.
To his astonishment, the two objects had disappeared.
Another two years passed and Galileo again
trained his telescope on Saturn.
The puzzling bulges had returned.
This drawing shows how close Galileo came
to solving the riddle,
but he went to his grave without ever knowing the answer.
A half century would pass before the Dutch scientist
Christiaan Huygens realized the bulges were rings.
As for their appearing and disappearing,
when the rings are viewed from Earth edge on,
they all but disappear.
As time passed, Saturn came into closer focus,
and in 1979, NASA's Pioneer 11 spacecraft
gave the world the first closeup look
at the planet and its rings.
- We received several pictures yesterday afternoon
and evening, and we'd like to run through some of those now.
This is the one that came in here
at about three o'clock yesterday afternoon.
This is by far the most spectacular picture
that we have so far.
This is raw data.
It has not been processed in any way.
We can see the big banded planet and, of course,
the ring system is very prominent in this picture.
Also prominent is Saturn's largest moon, Titan,
in the upper right-hand corner.
- [Narrator] The two Voyager flybys soon followed,
offering even more captivating views and discoveries.
What these missions found left scientists
clamoring to go again, and not just to pass by,
but to stay.
A blueprint and even some spare parts
for just such an adventure already existed.
NASA's Galileo mission,
that sent an orbiter and a probe to Jupiter.
Advocates in Europe and the United States
argued for a similar mission destined for Saturn,
one composed of an international consortium.
How such a project with all its complexities
could be done, no one really knew.
Sorting out roles, responsibilities, and especially funding,
took the better part of a decade.
The European Space Agency offered to build the probe,
named Huygens, to land on Saturn's moon Titan.
The Italian Space Agency would build the main antenna
and communication system.
The spacecraft thrusters and the main engines
would be provided by US commercial space companies.
And NASA's Jet Propulsion Laboratory signed on
to build and fly the spacecraft,
to be named in honor of the 17th century
astronomer Giovanni Cassini.
JPL would also provide overall management of the mission.
In total, 19 countries would provide hardware,
while scientists would come from 26 nations.
- Good morning.
I wanna welcome all of you to JPL,
and at the beginning of what is gonna be clearly
a very exciting mission.
I know that a lot of you have a...
- [Narrator] This is the first gathering
of Cassini Huygens scientists and engineers,
their goal to transform this complex partnership
into a functioning team.
- Our Congress has had some agony over the program.
For a time it looked as though only Cassini
would be approved.
- [Narrator] There are layers of unease in the room.
The Europeans want to know that they'll be
treated as equal partners.
And there are also concerns about US reliability,
given that NASA has recently dropped out
of another partnership.
- We're going to have to operate
under a very strict fund ceiling,
one that is imposed by Congress and an unyielding schedule.
And we all have great challenges-
- [Narrator] NASA has already warned
that the mission will be canceled
if the project strays over its budget.
All eyes are on Cassini's first program manager,
John Casani, who has already spoken of eliminating
some of the science instruments.
- Seriously like to welcome everybody.
Nice to be here.
A lot of old friends, a lot of new faces,
which I hope we'll be friends before we're through
with this process.
But those of you who don't know me,
will find out a lot in the next couple of years.
This will require doing business in a fairly drastically
different way than we've done before.
We are all gonna have to strive for,
as we go through this process, is a continual search,
as my old friend Gentry Lee used to like to say,
for the least unacceptable solution.
There are gonna have to be compromises.
We wanna work with you.
- [Narrator] This was not what scientists had hoped to hear.
- I think this is a very severe degrade
in the capabilities of this mission.
- What we did was we did all of these things
to finally get down to something that we could afford.
- That sounds to me like a very unwise thing to do.
I mean, the essence of this mission is to get data back.
- [Narrator] The friction between what scientists want
and what engineers can do will be a theme
running throughout the lifetime of the mission.
So, we'll be deciding which of Cassini's
12 different science instruments will have priority
at any given time.
First up to plead his case is the head
of the science radar team, Charles Elachi.
- Good morning.
I understand from Dennis that the first speaker
gets everything he asks for.
There is a good thing and a bad thing about the radar.
The good thing is that for every Saturn orbit,
we need to operate only for one hour.
You can have all the rest of the time, but one hour.
The bad thing is that when we turn it on,
the lights on the spacecraft will dim,
you know, it'll go down.
- [Narrator] Representing the needs of the imaging team
is its leader, Carolyn Porco.
- Rates which are lower than that.
After all, we know what it will take
to image the objects at Saturn,
that we know are there.
My question is, what is it that's there that we don't know
and we want to have a very stable platform
and be able to do long exposures.
These are issues that ring scientists
stay up late at night worrying about.
- We are running a bit behind schedule
so we shall skip the coffee break,
but there is still coffee for those who can't survive.
- [Narrator] One after another,
the science teams take to the podium to make their pitches
and at times to express their displeasure.
- Okay, this is one of the smaller teams,
and I suppose one of the smaller instruments,
although perhaps not as small as the project might like.
I'm afraid I have to say that we have to have
an instrument that performs best
within the planetary environment.
So life is not as simple as perhaps
some people have seen it.
- The other challenge that we've had here
is a recognition over the past few months that the...
- [Narrator] Hoping to resolve these conflicts,
Casani offers up an unexpected plan
to put the scientists more in control.
- We need to incentivize you to do the best job
of making the best estimates of what it's gonna cost
at the time of confirmation.
- [Narrator] Instead of having decisions made
from the top down,
Casani proposes establishing a trading system.
Each science team will be given a defined amount of money,
mass, power and data rates.
If later they need more of anything,
they will have to work with the other teams
to solve their problem.
The scientists agree to this unusual bartering system.
It is the first major step in building
a functioning international team.
- Any questions?
All right, Dennis, thank you.
- [Narrator] By the fall of 1997,
what had once been just blueprints
are now real pieces of hardware.
For over the last six years,
the mission has managed to survive being canceled,
something another NASA spacecraft
meant to rendezvous with a comet and an asteroid,
was unable to do.
This was part of a new NASA strategy to cut back
on large and expensive spacecraft.
And there was no disguising Cassini's size.
It remains, to this day,
the largest US interplanetary spacecraft ever built.
Standing three stories tall, when fully loaded,
it will weigh 12 and a half thousand pounds.
- The first time I saw the spacecraft together,
when we stacked without the blankets,
I must have stood in the visitor gallery for 30 minutes.
And it's... I don't know how to describe it.
It's not yours anymore, you know.
Even though I had been intimate with each piece
and part of that spacecraft and put it together
wire by wire and in part by part,
to watch it come together as a whole entity was incredible.
We were without words standing out there.
- Every now and then we'll be working in here
and you'll think, wow, this is going to Saturn
and this probe is gonna land on Titan.
And this is going somewhere where we've never
seen things before and you get goosebumps from it.
- [Narrator] The spacecraft has been designed
with redundancy as a priority.
Each critical system has an identical backup.
And its advanced software will allow the spacecraft
at times to fly on its own,
and even self-repair computer glitches.
In Cassini's interior are some 22,000 wire connections
and more than seven miles of cabling.
- I'm technically an engineering assistant,
and what I do is cabling for the spacecraft
and I've been doing it for 20 years.
One of the really positive points about our mechanical team
is that they never say no.
They never seem to tire.
They're always up.
(chuckles) I don't think we could ask for a better team.
- [Narrator] One of the last assembly tasks
is to cover this bare spacecraft with blankets.
Using machines more often used for fine tailoring
than engineering,
this reflective material is cut to protect the spacecraft
early in the mission, when it flies toward the sun.
This black fabric will do the opposite,
absorbing and retaining heat out at Saturn,
where sunlight is only 1% the strength found at Earth.
The layers will also provide shielding
from micro meteoroids,
tiny particles of dust that could damage
the spacecraft's electronics.
This is tedious work,
cutting, stitching and fitting hundreds
of individually measured pieces.
It is a job made even more challenging
knowing that this intricate space quilt,
like all of Cassini's major components,
will have to be unmounted for shipping to Florida,
where everything will be reassembled again.
- We have had less problem with this
than I can remember having on any other spacecraft.
It's almost scary.
It's just beautiful.
No problems.
No major problems anyway.
- [Narrator] While transforming Cassini from a blueprint
into a real spacecraft had gone exceptionally well,
getting to the final design had been torturous.
Facing budget cuts, the project was forced
to make another least unacceptable decision.
Instead of dropping science instruments,
the spacecraft itself was scaled back by eliminating
the scan platform,
a kind of turntable required by some instruments
needing motion.
Without the platform, the entire spacecraft
will have to rotate to aim at targets,
resulting also in less observation time.
But all of the science instruments have survived.
Operations are now almost complete
for the launch of Cassini Huygens.
Already on the launch pad is the Air Force's
heavy lifting Titan 4B
Cassini and the probe have been reassembled.
One of the last procedures involves
loading onto the spacecraft its power supply,
72 pounds of plutonium encased in
what are called radio isotope thermoelectric generators,
or mercifully called for short RTGs.
RTGs have been used on previous missions,
but recent nuclear power plant accidents
and the loss of the Space Shuttle Challenger
have heightened public fears of a launch accident
spreading nuclear debris.
Hoping to stop the launch,
anti-nuclear groups file lawsuits, petition the White House,
and hold demonstrations at the Kennedy Space Center.
- Since this is the last public forum to ensure the public
that everything is going to be all right,
could you do that one last time
and use your best argument to persuade,
perhaps, some of your opponents?
- RTGs were designed for accident conditions.
We've designed them, we've tested them,
we've analyzed for it, we've gone through
a very lengthy review process.
And in fact, these are very safe to use.
There's not a risk to the public,
even if there is an accident.
- Would you all confirm your faith in this mission
by telling us how many family members, kids,
and grandkids you have here watching this launch with you?
- Well, I have 30 members of my family here right now,
including my two granddaughters.
There's more on the way.
(crowd laughing)
I don't know if I have more grandchildren on the way,
but I have more family on the way.
The reality is there's no technology on the horizon
that has the promise to be available
in the foreseeable future at all
that could be used for feigning power
way in outer space,
where there is effectively very little sunlight.
At Saturn, we've got a 1% of what we have here on Earth.
We know Cassini is safe.
The generator is designed to be robust in the environments.
We do not rely on success.
We make it compatible with the environments
that might be generated and it's safe.
I invited everyone I love to the launch.
- [Man] Will there be information
on the success of this launch too?
- Absolutley.
You can find us with a bottle of champagne some place.
- [Man] FLC, we have 325 and 326 complete.
Roger.
- [Man] EA and LCC 327 and 328 on time.
Roger.
- [Woman] LCC, roger.
- [Man] The Air Force launch controller
has given a clear to launch.
We've got to go from the range
to proceed with the countdown.
- [Woman] Launch sequence started.
- [Man] T minus 10,
nine,
eight,
seven,
six,
five,
four,
three,
two,
one,
and liftoff of the Cassini spacecraft
on a billion mile trek to Saturn.
(cheering)
Pitch program is in.
(man talking indistinctly)
- [Man] We have cleared the tower
and the Cassini spacecraft is on its way to Saturn.
T+20 seconds.
All systems are go.
Standing by for solid rocket booster separation.
And the solid rocket boosters have been jettisoned.
- [Man] Item 149 and 150.
- [Man] All systems go.
- [Man] All CAS core stations, ops engineer,
launch vehicle reports payload fairing jettisoned.
- This launch was, for all practical purposes, perfect.
It was just right on target.
And the navigation corrections that we normally,
routinely expect to have to make
for these kinds of launches was very small.
It was an exceptionally good launch.
- [Narrator] But the launch, as good as it was,
was not powerful enough to send Cassini directly to Saturn.
To get there, mission designers had long before
devised a flight path, using mother nature
to gain extra boosts of speed by flying by planets,
what are called gravity assists.
Cassini's route required two inward swing bys at Venus,
next back to Earth, then outward to Jupiter,
and finally on to Saturn.
In all, a journey of over 2 billion miles,
lasting nearly seven years.
During the first Venus encounter,
Cassini grazed just above the planet's surface,
gaining an extra 16,000 miles per hour of speed.
- The Cassini spacecraft has now been in space,
in flight, for a little over eight months.
And the performance of the spacecraft has been
essentially flawless.
Typically on spacecraft like this, of this complexity,
there are issues, complications of one sort or another,
that we have to work with some of our ground-based
command capability.
For the Cassini spacecraft, this just hasn't happened.
It's a remarkable spacecraft.
- [Narrator] True enough,
but Cassini is not yet a fully complete spacecraft.
- We had enough flight software on board at launch
to be able to fly the spacecraft, operate it, navigate it,
and not a whole lot more than that.
- When we launched, we had seven years
to get to Saturn and we actually
completely changed out the computer system twice in flight.
We would take the old computer software
and then load up the new software in the backup computer,
watch it for a while, make sure it was stable.
And then we would swap and make the backup
the prime computer.
Make sure it was stable.
- [Narrator] As engineers worked on completing
Cassini's software, scientists started lobbying
to begin using their instruments
far ahead of the agreed upon schedule.
- The cartoon.
You gotta see the cartoon.
You gotta see the whole thing.
So the idle spacecraft is the devil's playground.
For the first three years,
we weren't supposed to do anything.
We were supposed to fly a rock.
And we were just gonna go take this,
take the spacecraft, correct it engineering wise,
fly it by Venus, a couple of times by Earth,
and we really weren't gonna do much science.
And here were the scientists saying,
"You've got this great spacecraft,
everything's working on it, you don't have to check...
You know, you don't have to redo your thermal.
You don't have to redo this.
Let's do science."
And so I came in one day and this was on my door.
The idle spacecraft is the devil's playground.
I swore for years that one of the scientists
had put that on my door.
It was my boss.
He put that on my door.
- [Narrator] For the most part,
the scientists were accommodated,
but the project's priority was first
getting safely past the Earth,
which occurred in the summer of 1999,
giving Cassini another 12,000 miles per hour of speed.
The next milestones were passing beyond the orbit of Mars
and the region of the asteroid belt.
Then came Jupiter,
where Cassini saw raging storms,
some centuries old.
Cassini also teamed up with the venerable Galileo spacecraft
to jointly measure Jupiter's magnetosphere,
a bubble of charged particles trapped
within the planet's magnetic field.
At closest approach, Cassini took this image.
At that time, the most detailed view of Jupiter ever seen.
The Jupiter encounter served as a full dress rehearsal
for what awaited at Saturn.
It revealed there was work to be done
in addressing Cassini's design compromise.
The lack of the scan platform that would have allowed
simultaneous use of science instruments,
needing either to move or to be rock steady.
- It meant you had to turn the spacecraft
every time you wanted to point an instrument someplace.
And we had 12 instruments,
and each instrument generally had
different pointing druthers, if not in fact,
hard and fast pointing requirements.
And so there was an awful lot of negotiation
that went on between the different science teams,
the different instrument representatives,
in deciding who was gonna get to control
the pointing of the spacecraft when.
It took a lot of time, a lot of negotiating,
a lot of compromises to make that work.
- [Narrator] Despite this restraint,
Cassini could now boast of being the most capable
interplanetary spacecraft ever sent out
into the solar system.
After a journey of nearly seven years,
Cassini and the Huygens probe are nearing Saturn's doorstep.
Whether two decades of dreaming, planning,
building, and undertaking this arduous journey
will be rewarded, will soon be known.
For just ahead is the most dangerous moment
that Cassini will face.
SOI.
Saturn Orbit Insertion.
No one is more excited, or anxious, about this moment
than Charles Elachi.
In addition to still being the team lead
for Cassini's radar experiment,
he now heads JPL.
- Cassini is probably one of the most exciting missions
ever undertaken by the US and it deserves more credit.
So when we come to the orbit insertion,
after advocating for it, selling it,
building it and flying it,
it was a really very sobering moment.
The engine better fire, otherwise we'll end with a fly by.
You have to remember that we had the Mars Observer,
where when we turned on the engine, the thing disappeared.
- [Narrator] 11 years before,
as Mars Observer was approaching Mars,
the spacecraft was commanded to pressurize
its propulsion system.
The spacecraft was never heard from again.
It's believed a massive rupture in the fuel lines occurred,
putting the spacecraft into an unrecoverable spin.
We have about 15, 20 minutes.
This is Bob Mitchell, who is the project manager.
- Okay, well, I think we've got what'll be
a rather interesting program laid out here
for you this evening.
Certainly gonna have a little drama to it.
I was kinda confident, but I was worried, concerned.
Nervous might be the best word as well.
- [Narrator] To slow down enough to be captured
by Saturn's gravity,
Cassini will have to turn on its seldom used engine
for 96 minutes.
Anything less could result in flying past the planet,
never to return.
The flight path will take Cassini and the probe
up through and back down a gap in Saturn's rings.
There's worry that there could be particles
in these regions large enough to damage,
or even destroy, the spacecraft.
- I think as a ring scientist,
my greatest concern was really crossing through that gap
in the F and G rings.
It would only have taken one marble sized particle
in the wrong place in the spacecraft
to perhaps have ended the mission.
So for me, the most, you know, breathtaking,
the heart stopping time, was really
crossing through the ring plane.
- [Narrator] To reduce the risk,
Cassini will fly through the gaps with its high gain antenna
facing forward to act as a shield.
During these times, the only signal coming back to Earth
will be from a smaller antenna transmitting a single tone.
The pitch, or frequency, of the tone will vary
with changes to the spacecraft's speed.
What's known as the Doppler effect.
This will tell engineers how the spacecraft is performing...
or not.
- Zero is the reference frequency,
the nominal frequency that we would see
if there were no burn.
So if the motor never ignited,
what would happen is this line up here
would just go right straight across.
I would lie in bed at night and think about
what other tests should we do?
What other question should I be asking?
What should we be poking at here that we haven't done yet?
And this corner right here corresponds to
where the burn should end.
There wasn't any single thing that I could point to
and say that thing right there
has a fair chance of biting us.
There just wasn't anything like that.
But when you consider all the things that had to happen...
or not happen,
there were enough of them that the aggregate of them
was cause for being nervous.
And I was.
That would be cause for some level of concern.
- [Julie] SOI was such a, just such a team effort.
We chased everything that could go wrong
down the rabbit hole.
We went down every path of, if this goes wrong,
what do we do?
If that goes wrong, what do we do?
There were 10,000 tests run to put together that insertion.
- Something we've been preparing for
for four or five years, testing and testing,
awfulizing all of the possible things that could go wrong.
And this was one of those moments where you're either
in orbit or you're a billion dollar fly by.
- Things continue to go well in Cassini mission control.
We're approximately 33 minutes from burn start.
There's our flight director, Julie Webster.
This is one person we hope to not hear from tonight.
This is system fault protection engineer, Paula Morgan.
And if we hear from fault protection,
that means we've had some sort of anomaly on the spacecraft.
Doug Johnson, our radio science and SOI communicator.
He's the one reporting most of the events we'll see tonight
through that Doppler signal.
- [Narrator] Also on console is Jan Berkeley.
She first worked at JPL as a college intern.
Now she's a key member of the Cassini team
that creates the computer sequence commands
that operate the spacecraft.
- We would run them, make sure that there were
no problems with that.
If we needed to do testing, we would schedule testing.
We were the ones that actually sent them to the spacecraft.
And then we watched them clock out.
That was the tense moment, was not pushing the button,
it was waiting for it to come back, that it worked.
And Saturn was so far away that it would take three hours
just to get there and come back.
- Current speed of the Cassini spacecraft:
22.2 kilometers per second,
which is just under 50,000 miles an hour.
And increasing as Saturn's gravity draws us in.
That's Shin Huh, our SOI systems engineer.
Shin has eaten, breathed, slept, and lived SOI
for many years.
Tonight is his big night.
- All stations on that SOI systems.
Just an advisory, we're coming up on the time
for the critical sequence will initiate the turn
to the SOI burn attitude.
The burn command will be sent at 7:35:35 PM local time.
Flight director, SOI systems,
all subsystems report the spacecraft data is nominal
and ready to support SOI.
- [Man] Okay, I copy that.
SOI, comms flight director...
- [Todd] We're waiting.
- Copy telecomm
A JPL tradition has begun,
starting in the back of the Mission Support Area.
This is the consuming of the lucky JPL peanuts.
Doug Johnson just reported a signal,
we've survived the ring plane crossing
through the F and G rings.
(applause)
One hurdle down, one to go, with the start of the burn
a meer nine minutes away.
- [Julie] ACE flight director on FSL court.
Are you still tracking Canberra on B2?
- [Man] That's affirmative.
- Let's go ahead and switch Canberra over to B-Zero.
Go ahead, NAV-1.
- [Man] We can confirm that we are receiving
one way data from the DSN.
- [Julie] One way Doppler from DSS14?
- [Man] Yes, that's affirmative.
- Navigation can also confirm we're receiving
the Doppler data.
We've been able to verify that the turn
to the SY burn attitude is complete.
We're approaching two minutes before the SOI burn.
Hopes and dreams of thousands of scientists
and engineers are resting on the next few moments.
So Godspeed, Cassini Huygens.
May we see you in orbit.
- We're gonna drop in.
- On the Doppler display, what we're looking for
is a turning of the corner to start to follow that line
down to the lower right.
And that's our indication the burn has begun.
Flight, SOI comms..
- [Julie] Go ahead.
- [Man] We have a Doppler signature consistent
with engine turn on.
(cheers and applause)
- [Todd] Lots of high fives and celebrations
in mission control.
Congratulations all of you that have worked so hard
for this moment.
One minute down, about 96 minutes to go.
We're continuing to follow the nominal predicted curve
on the Doppler.
So the fact we turned the corner
means the engine has started.
The fact that we're following the line
means we're getting the right thrust out of the engine.
So more good news for the Cassini Huygens spacecraft.
- Way to go.
Way to go.
- [Narrator] There's now 90 minutes of waiting
until Cassini's engine is to stop firing.
The lull in the action affords a rare opportunity
to give members of Congress who are on hand
a very up close and personal tour.
It's a moment to witness history in the making,
and, as politicians well-know,
to take advantage of an excellent photo op.
- It's 7:42 PM in NASA's Cassini mission control.
The next thing we'll look for is an occultation
by the A ring around 8:05 PM Pacific time local.
At that time, we'll see an increased noise
in the Doppler signal,
similar to the increased noise there at the far left
of the Doppler plot.
And our final scary moment of the evening
will be to make sure to get the burn shut down.
The history making day for JPL, NASA, and the world.
- [Man] Flight, SOI comm.
- Go ahead, SOI comm.
- [Man] We have hit the A ring pretty hard.
- All right.
- [Todd] More good news from SOI Comm there,
the frightening looking change to our Doppler data
is totally anticipated.
This proves that Saturn's A ring is where we think it is.
And the Cassini spacecraft is where we think it is as well.
- [Man] We're continuing to track a two to three DB signal
with occasional outages through the A ring.
And we expect to see a nice strong signal,
we have the main division coming up.
- [Julie] Copy that, sounds good.
(phone ringing)
- [Todd] As we see, we're approaching the B ring,
and we must remember tonight, everything happening at Saturn
occurred an hour and 24 minutes earlier
due to that pesky speed of light, 186,000 miles per second,
our interplanetary speed limit, if you will.
- [Julie] Go ahead SOI Comm.
- [Man] After a brief peak up to 11DB,
we have now exited the division.
- Copy.
- [Man] What just happened?
- They just announced that we are now
a captured object around Saturn.
We are now an orbit... an orbiter.
- First in history around Saturn.
- There you go.
First man-made orbiter around Saturn.
Voyager, eat your heart out.
- [Man] SOI systems, this is contingency.
- Closest approach is just a little over two minutes away.
And given that, it's probably about time
for our Saturnian weather forecast.
Predicted temps today, -226 degrees Fahrenheit
or -143 degrees Celsius.
Winds of 1100 miles per hour or so.
Chance of helium rain inside the interior, 100%.
Hurricanes the size of the Earth.
Cassini would do well to batten down the hatches.
Closest approach is upon us with a speed
of almost 69,000 miles per hour.
And the speed HAS started slowing.
- [Man] Flight, SOI Comm.
- [Julie] Go ahead, SOI Comm.
- [Man] The Doppler has flattened out.
(cheers and applause)
(indistinct chatter)
- [Todd] Okay, we have burn complete here,
for the SOI orbit insertion burn.
Congratulations continue in mission control.
The high-fives begin in the back
of our mission support area.
I'm just hearing a report from radio...
- You did great.
You did great. - Thank you.
- My pleasure.
Here's to our lucky propulsion engineers.
Did a wonderful job tonight.
- Knowing that it survived and was there
and we were ready to, you know,
get to the meat of the science and get these great images.
It was a wonderful moment.
The voyage begins.
We made it, like, we did it.
- Fantastic job.
- Now we're gonna put your ECAP in.
(laughing)
- [Todd] I was just informed by my management,
she'll put my performance evaluation in.
I'm glad she waited until our success tonight.
It's alive.
- It's alive.
(gentle music)
- So there's this amazing elation
and then almost immediately a crash,
just because we're exhausted and tired,
but I couldn't sleep.
And so I stayed in the MSA,
and the images of the rings were playing back,
and slowly people started to gather around these images,
which no one had seen close up images
flying right over the tops of the rings.
And there were just goosebumps.
That's a memory I will never forget.
- This is way more ringlets, little pieces.
- [Narrator] Until now, the mission has been
mostly the province of engineers.
With these first ever closeup images of Saturn's rings,
the shift to science begins in earnest,
and there are hints of major discoveries ahead
from what already can be seen.
- I don't think you have to be a ring scientist
to imagine what last night was for us.
It was beyond description really.
It was mind blowing.
It was every adjective you could think of.
I'm surprised at how surprised I am at the beauty
and the clarity of these images.
They are shocking to me.
The spacecraft allows us a very steady platform.
This machine, you turn it, you point it, and it stays there.
It's like a tripod in space.
Anyway, I think ring scientists are gonna have a field day.
So thank you.
Wow.
(applause)
- [Narrator] Cassini's arrival coincided
with a time when the planet was well lit by sunlight,
providing extraordinary views of the rings.
Saturn, plus the rings, span about a quarter million miles,
and they would fit in between the Earth and its moon.
And yet for all of its wide expanse,
the rings themselves are paper thin,
only about 10 feet thick.
If you could scoop up all the ring particles,
there would be less mass than one of Saturn's
small moons named Mimas.
- [Narrator] From a distance,
the rings cast off a sense of serenity,
but they are as complex and chaotic as they are beautiful.
For they are made up of countless numbers
of disorderly objects of different sizes and shapes.
This is a simulated image based on radar observations,
showing particles sizes found in different regions
of the rings.
The color purple represents where there is
a preponderance of objects smaller than two inches.
Particles in green are about an inch in size.
The blueish bands are still smaller.
The white bands are dense regions that radio signals
were unable to penetrate.
This false color image highlights what can be seen
in the ultraviolet.
The turquoise colors represent water ice.
The red colors are a different kind of particle.
Uncertain as to what it might be,
the scientists decided to name it dirt.
- Cassini was also able to measure
the temperature of the ring particles,
and the rings that had the most dirt or pollution
were slightly warmer than the bright icy rings.
- [Narrator] And, despite being made of
mostly cosmic dust and ice,
the rings contained some structures as large as a house.
And as scientists discovered to their astonishment,
even transitory mountains.
- There is a unique moment in the Cassini mission
where the sun was edge onto the rings,
and that allowed us to see anything that would stick up
above or below those 10 feet thick rings.
Then lo and behold, we found what looked like mountains
casting huge shadows on the rings.
And it turns out that the rings of Saturn
are not like just individual particles,
but a lot of these particles stick together
and grow into larger and larger particles.
But these clumps of particles are ephemeral.
They don't last for a long time.
They can be broken up and then reformed in to new particles.
- [Narrator] Saturn's moons and smaller moonlets
also influenced the rings.
Even orbiting rubble piles hold a kind of sway.
Altogether, they help shape the boundaries
of Saturn's rings,
herding in particles that might otherwise
rain down in a torrent on the planet
or escape into deep space.
Meanwhile, particles from some of Saturn's moons
are constantly shedding off,
helping to preserve existing rings or creating new ones.
Among the unexpected discoveries within the rings
were these propeller like objects.
- Propellers are these largest clumps of ring particles,
and they get big enough so their gravity
wants to push apart the rings and open up a gap.
And then there's not quite enough gravity
to open it up all the way.
And so you see these little propellers
sprinkled throughout the rings,
especially in Saturn's A ring.
- [Narrator] A mystery dating back to Voyager
was the appearing and disappearing of ghostly spokes.
Cassini determined their cause.
Electrostatic charges that lift up dust particles,
where they levitate for a time above the rings.
There remain two fundamental questions
lacking definitive answers.
The first is knowing how the rings came to be.
- So many things about the rings are unexplained even now.
There are a lot of ideas for how Saturn's rings
initially formed.
One of those is that perhaps the rings formed
from the material that was left over
from when Saturn formed.
So if that's true, then the rings are old,
as old as Saturn itself.
Other ideas: say perhaps an object may be a comet,
or a meteor, came in too close to Saturn,
was torn apart by Saturn's gravity,
and then created the rings.
Or perhaps a moon wandered too close to Saturn
and was torn apart.
And so then the rains could be as young as maybe only 10
or a hundred million years old.
- [Narrator] Along with determining the origin of the rings,
understanding their fate is also an unanswered question.
But the adage that nothing lasts forever
likely applies even to them.
- As micro meteoroids continue to bombard the rings,
and some of the innermost particles fall into Saturn
and actually water the planet,
the rings are getting lighter and lighter with time.
And so perhaps in another few hundred million years,
Saturn's rings as we know it might be gone.
Maybe we'll be left with narrow rings
like we see in the Uranus system.
- [Narrator] And one day long from now,
Saturn's glorious rings might disappear altogether.
One more reason to enjoy them while we can.
Next time on "JPL and the Space Age",
Part Two of "Triumph at Saturn"...
With Cassini safely in orbit, science takes center stage,
beginning with the dramatic descent of the Huygens Probe
to the surface of Saturn's moon Titan.
- [Man] We knew Titan was a tough target,
was going to hold its secrets tightly.
And so we designed this mission to hit it
with everything we've got.
- [Narrator] In the years that follow,
one unexpected discovery after another will be made,
earning this international mission
accolades from around the world.
- Science is about what is,
and engineering is about what can BE.
The Cassini-Huygens program has demonstrated
the best of both.
The number of your new discoveries
is nothing short of amazing.
- [Woman] I would say Cassini's discoveries
fundamentally altered the way we look at our solar system.
Around one planet, we find two moons
that could potentially be habitable,
have the key ingredients to support life.
- I have more than a passing interest in Saturn
and its family of moons.
When Cassini was launched, we knew only 18 moons.
I understand there's now 60 and counting.
I can't resist the temptation to say,
my God, it's full of moons.
- [Narrator] "Triumph at Saturn" Part Two, next time.
(gentle music)