JPL and the Space Age: Triumph at Saturn (Part II)

goodbye cassini, the fini bravo of your mission, have some linguine, you showed us the rings of

saturn

and many nice things, the probe intensifies, it dived in early 2005, it landed on titan, it was exciting, your mission to fail in supplies dazzled our eyes now dives into Saturn, vaporizes in 1997 an ambitious An international mission is launched to Saturn in Wood for the first time. It attempts to place a

space

craft into orbit around the planet and land a probe on a moon in the outer solar system, but it was a mission that had to fight its way just to reach the launch pad.

Congress has suffered some agony over the program that we are going to have to operate under a very strict funding ceiling and an inflexible schedule that we are all going to have to strive for as we move through this process, it is a continuous search for the solution less unacceptable. The trip to Saturn took seven long years and being captured in orbit depended on what would happen for just three hours We chased everything that could go wrong down the rabbit hole We went down every path If this goes wrong What do we do if that goes wrong? wrong, what do we do with all the stations in those soi systems?

Just a heads up that we are reaching the moment when the critical sequence will begin the shift to the FBI's fire attitude. This was one of those moments where you're in orbit or you're a billion dollar flyby, yeah, wait, that's what I'm coming from, ahead, with Cassini safely in orbit. Science quickly took center stage, starting with dazzling images of Saturn's rings. I am amazed at how amazed I am by the beauty and clarity of these. images that shock me Investigating Saturn's iconic rings will be just one

part

of what will turn out to be 13 years of discoveries about the Saturnian system and what will be discovered about Saturn's moons will even transform the way we think about our solar system and how to open it Breaking new ground for the future of

space

exploration around a planet, we found two moons that could potentially have the key ingredients to support the

triumph

of life on the next Saturn.

For some scientists, Saturn's lunar titan has been a higher priority for exploration than even Saturn or any other. planet, this is because Titan may resemble what Earth was like billions of years ago, making this moon a kind of time machine that preserves and freezes many of the conditions that led to life on Earth. our planet. Titan is the only moon in our solar system that has a dense density. atmosphere composed primarily of nitrogen, like the Earth, there are smaller amounts of methane and ethane that break down into organic compounds creating the moon's orange haze. Titan's extremely cold temperatures turned some gases into liquids, leading scientists to wonder whether Titan could have oceans that were not made of water but liquid methane and ethane.

These questions made unmasking Titan a major goal of the cassini-huygens mission and before the launch of the huygens probe cassini would have the first opportunity to see this moon up close with the hope that the spacecraft could see the surface of titan scientists were eager to share the flyby of more than five hours live with the world and you are watching live coverage from the Jet Propulsion Laboratory in Pasadena, California, tonight the Cassini spacecraft has its first close encounter with Saturn's largest and most intriguing moon. Titan, this is the closest we've ever been to Titan and for the next five and a half hours we expect to see the best images we've ever seen of Titan and here on NASA TV you'll see those images just a few minutes after they arrive. the ground and right on cue, images began to flow downward, but it quickly became apparent that Titan was not ready for its first close-up.

We just got exciting news that we got the first image right, so this looks like, um, the gaps that are needed. a bit of processing to highlight features that at first glance appeared to be black and white blobs left scientists and viewers baffled as to what they were seeing look at that look at that and we don't know what something stands out in your mind at this point yeah , it's been a very strange night if you put me up against a wall and said what is a cloud and what is not a cloud I couldn't really tell you I guess a lot of this is surface features yes, these are low On the contrary, no I'm really sure what we're seeing here with us now is Torrance Johnson, one of the imaging scientists giving us a general idea of ​​what it means.

Well, I think, first of all, the main thing this night means to us is "us." We've had a very successful meeting, we're really looking at a lot of data here and when you saw some of these things coming in, clearly there are things that can be seen there on that surface, understanding that it's a different topic and one of the things that everyone All of us involved in the project have been talking about this kind of cooperative scientific approach for a long time. We knew Titan was a tough target and was going to guard its secrets tightly, so we designed this mission and experiments to hit it with everything we could.

We have this is our first opportunity to do that. We're really going to have to do a full scan of Titan's body to figure out what's going on in this encounter. We confirm that Titan would be as complex as it is dark. Fortunately, there are still many Cassini flybys ahead, but the next step in exploring Titan is the European Space Agency's Huygens probe that will attempt to descend to the surface of the Moon. The procedure here is pretty standard. Let's follow him throughout the mlp. The idea. It is a series of short reports. Eight weeks have passed and it is Christmas Eve, as Cassini-Huygens team leaders hold a meeting about whether to release the Huygens probe.

We had two opportunities to update this flight titan there are no known technical issues to deal with making this meeting mostly a formality the navigation has followed a precision path so there was no need for us to make any updates . The tracking data has been absolutely excellent lately. Dsn has been doing a very good job. work and Julie's team has done a wonderful job, recently giving us some really great viewers, so without that, don't jinx it, jerry, right? Based on what we've heard here from representatives of the people who did the work, it's very clear that the JPL orbiter,

part

of this team, is ready to continue with the probe, the probe, the support team is also ready, as well that we are green for tomorrow, so let's go, well, let me add my enormous thanks from the European side.

For the tremendous collaborative effort on the American side, it's been fantastic to work with you and I think we're all very grateful, so let's go well, we already did it. Southwood's comments were candid, as four years earlier the mission had faced what seemed like an unsolvable problem - a design defect found in the Huygens receiver located on the Cassini spacecraft - a flight test revealed that the receiver was incapable of to adjust for Doppler shifts changes in radio frequencies that would render Huygens data almost worthless an important solution required a practical solution impossible to do with the probe a billion miles away knowing that little could be done with Huygens the Better hope rested with Cassini when mission planners realized that adjustments to the spacecraft's trajectory could minimize radio frequency changes, this required Cassini to fly higher above Titan and at a relatively slower speed. which would allow data to be recorded accurately as the probe descended, but this solution was not free, it would cost Cassini a quarter of its reserve fuel.

This sacrifice confirmed that Cassini-Huygens was truly an international partnership, as without this decision, Huygens was safe. From being seen as a failed mission, the crisis was now just a memory and the time had come for the probe to separate from Cassini to begin its dangerous descent to Titan. There is a JPL that says that for some celestial reason the important events of the mission They always seem to happen on holidays weekends late at night or a combination of all three the publication of the research is no exception to the rule it's christmas eve i would like to start the survey in five minutes to show your support for the team cassini are leaders of the huygens JPL probe director Charles Alachi, Caltech president David Baltimore, and arrived just in time.

JPL veteran Tom Gavin, whose job title includes the phrase "Mission Success." The first aircraft carrier lock is 7.29. That's right, with the Huygens probe now alone in silent freefall toward Titan. For the next 21 days, the Cassini team can relax and enjoy the holidays, especially New Year's Day, because JPL was sponsoring a float in the Pasadena Rose Parade tournament, for the third time in the lab's history. float featured nine jpl missions, the one at the top was cassini the huygens dived into titan it is the most distant landing ever attempted the descent through the atmosphere is expected to take more than two hours the hope is that the batteries of the probe last long enough to reach the surface what it will be like no one really knows because there could be lakes or seas of methane the probe has been designed to float but first huygens has to survive the dive through titan's atmosphere the entry speed is more than 12,000 miles per hour, temperatures will soon rise to more than 3,000 degrees Fahrenheit.

If the heat shield does its job, the scientific instruments inside the probe will have no idea that an inferno is raging just inches away. distance after surviving the initial phase of the descent, the first of three parachutes deploys closer to the surface, the winds begin to calm and the titan The orange haze begins to clear revealing a surreal landscape below, so imagine descending to through a cloudy, hazy atmosphere and suddenly below you breaks this view of this very bright hill with channels carved by liquid with rounded pebbles that were evidently rolled and rolled by the liquid which is what the Huygens probe saw and showed us that methane is not only in the atmosphere but has been raining and producing weather and carving features into the landscape for long periods of time as Huygens lands in a

triumph

ant plop.

History is made and, better yet, the probe's batteries are still working. What Huygens sees appears to resemble a dry riverbed, right in front of it are rocks made of frozen water harder than stone. There are no signs of lakes or seas, but Huygens' view is just a point on a moon larger than the planet Mercury. Global reconnaissance will come from Cassini. In many of Cassini's orbits around Saturn, the spacecraft will fly close to Titan. Allow navigators to use the moon's mass to alter trajectories while conserving fuel. These flybys are also opportunities to use Cassini's powerful radar to penetrate swathes of the moon's hazy atmosphere to radio waves bouncing back from the moon.

The surface of Titan can be converted by scientists into topographic maps piece by piece stripe by stripe titan is revealed let's start at the beginning and run to the end and see what interesting things we see and maybe you can point out the things you've seen too. Well, here's the new strip coming through here. Titan really is, in some ways, a kind of cosmic strip act because we can't see the surface and the normal wavelengths that our eyes would use and the radar operates by making images in narrow strips and so strip by strip in different places Titan has been revealed on that slide you can see a feature that runs almost perpendicular to the altimetry track so we see the At the end of the dunes here and you see the dunes fade away and get brighter which is interesting here you see dunes massive masses made not of sand but of carbon-containing organic molecules from the email traffic last night I watched together, no one sees a magic island in the data. that we have correct I think it is correct tell me what you want to expand on at the beginning that a large dark basin turns out to be a lake full of methane is the first of hundreds of lakes and deep seas that will be found more than observing this lake show a subsurface reflection so the depth of this particular lake is about 100 meters as we can see on the axis of the image it is correct to come out of this that the small lakes do not seem to be anything shallower than the larger lakes The discovery of Titan Strange It is a continent-sized area called Xanadu.

Here there are cannons andmountains that look like no other place on this moon. It's like a scientist saying he's from another world. One thing, just to make a quick comment. I'm always very impressed with the radar planning teams, they absolutely hit the mark because, you know, it's so far away, flying at miles per second, and they put it right on target. Good job, the titan can even have volcanoes. They gush out an icy mixture of water and other materials and this water comes from an ocean hidden beneath Titan's icy shell and every time water is mentioned it doesn't take long before the question arises as to whether this is a place that could possibly could support life on a giant titan the size of The planet Mercury has a global ocean of liquid water beneath its icy crust, as well as methane lakes and seas at the north pole, and we wonder if those methane lakes and seas could support life. a different kind of life, so that really opened our eyes.

There's still more. I discovered that this moon has a climate and seasons, here it does not rain water but methane that floats like snow. It is so similar to the Earth that this is a very familiar place. The chemistry in the atmosphere is much more complex than expected and the system as a whole is just as intricate as the earth in terms of the atmosphere interacting with the surface and the materials on the surface, the site has a methane cycle, just like the earth has a water cycle and being able to see it in action, see the lakes on the surface, the channels that have been carved into the surface and then seeing the clouds forming in the atmosphere and the rain, the effect of the rain on the surface, that whole cycle has been one of the absolutely spectacular things, the moon Saturn, Enceladus, was also a target of special interest for Cassini, it is the most reflective object in the entire solar system and a great mystery was why this moon seemed to have so few craters.

Theories abounded as to whether there might be some internal heat source that melts the ice on the surface and then replenishes it. The holes could be volcanoes or geysers that explain the moon's bright façade, or was Enceladus simply a dead, airless ball of ice. Cassini would find the answer by sending shock waves through the scientific community, all triggered by one of the spacecraft's lesser-known scientific instruments: the magnetometer is a kind of high-tech compass that measures magnetic fields and is so sensitive that it can even detect the spacecraft's own magnetic emissions to cancel out those unwanted signals.

This instrument was abandoned at the end of Cassini's long boom in this flyby. One expected there would be much of the solitary instrument. I must confess that we weren't expecting to see anything, so we didn't look at the data for a couple of days, um, and then when we went in and looked at the data, um. Only the magnetometer people can get excited about our data because you sort of plotted it on a scale where you look at it all day and we had to look at the movements on the plot and they looked strange, the expectation was that Saturn's magnetic field would extend directly and flow directly through Enceladus, instead the magnetic field curved around the Moon, there were also unexpected signs of ionized water vapor molecules, these were measurements that could be translated into sounds as the spacecraft was approaching and receding from Enceladus, so it was clear. that there was a source of water group ions in the vicinity of Enceladus and on top of that something strange was happening in the magnetic field, it seemed as if Enceladus was a much bigger obstacle to the flow of plasma and field coming from Saturn.

It was almost as if Saturn's magnetic field and the Moon's plasma had pulled us away from the Moon's surface without being sure of the accuracy of the data. Dowerdy and his team waited for the results of a second, closer flyby and I must confess that when we looked at that data we were immediately a little worried about the calibration of the instrument, but there seemed to be something in the data that pointed to an atmospheric signature of some kind and At that time we were talking about an atmosphere that covered the planet. Not everyone on Dougherty's team agreed across the board on one thing: Little Enceladus lacks enough gravity to hold an atmosphere in place in hopes of solving the mystery.

Dougherty proposed flying even closer to Enceladus on the next flyby. Doing so would alter the trajectory and scientific plans mapped long ago. But Dowardy's argument won the day when navigators charted a new course that sent Cassini flying just over 100 miles above the moon for the couple of nights before that flight. I did not sleep. What if we hadn't seen anything? Nobody would do it. I once believed something, said it again and didn't sleep well at all, but then we got the data back and it was spectacular in the south polar region. Cassini found the landscape free of craters but filled with excavated house-sized ice rocks.

Along bluish trenches that scientists called tiger stripes, the Moon would no longer be known for being smooth. Here was a fractured surface containing crisscross faults, folds and ridges. These cracks tell us that Enceladus is geologically alive from these fissures. Erupting geysers more than a mile deep, nicknamed True to the Cold, are continually spewing enormous jets of ice particles and water vapor. Speculation from more than a decade earlier that Enceladus' bright surface could be the result of ice volcanism turned out to be true. A momentous discovery that started with unusual moves on a graph I thought, okay, my reputation is saved, they're not going to think I'm crazy, but it also made me feel very proud of what magnetometer instruments can do because, somehow , you know, because we are just data that moves.

In a plot it is very difficult to get people excited about our data, you media guys, it is also very difficult to get you excited. The detection of geysers was surprising because it meant the existence of liquid water near the surface of this extremely cold moon and so on. it instantly made Enceladus a prime target for the rest of the mission. Previous plans were scrapped in favor of adding more flybys of Enceladus, including dramatic drops through plumes of smoke - what's that? And look at this little thing here, this circular feature is so complex that The question is whether they both come out of the tiger stripes.

It would be nice to get a correct temperature measurement. Look it looks almost like a river, but see it's in shadow, but we can still see it because the moon is so bright. so much multiple scattering Enceladus is as small as it is bright so small compared to the Earth and our moon, given its tiny size, it was thought that a long time ago Enceladus would have lost all its interior heat and what scientists wondered was that the columns of Enceladus will spray these heats. The answer has to do with Saturn's enormous tidal forces that create friction within the interior of the Moon, where there is an ocean of water, a tremendous discovery, and the liquid from this ocean gushes upward, creating the Moon's hot spots. and geysers that vent and from these columns, scientists discovered that the moon's ocean contained salts and complex organic molecules likely created by hydrothermal vents the exact conditions believed to have given rise to life on Earth during many of these discoveries. on this small moon were Cassini's greatest triumph for Enceladus is now one of the most promising destinations to search for life elsewhere in our solar system Cassini's discoveries during the first four years on Saturn raised new questions to be answered with a spacecraft in excellent health nasa expanded mission funding twice over the course of 13 years the spacecraft orbited

saturn

294 times no two orbits were the same determining the paths for these intricate loops is the work of real space scientists o , as they are called, course designers, are mathematical wizards who plotted courses through the labyrinth of more than 80 moons of Saturn and their route through the ring system must be classified as green, which is half the route. work of these three tour designers, the other half trying to please 200 scientists, this tour is probably yellow because I hate to keep having this back and forth email exchange it looks bad, I think we are assuming all the scientific requirements that, As you know, they could be such a thick stack, we are like a tour guide bringing a large group of children or scientists to Disneyland and the only problem is that we have to stay together as a group, we all have to do the same thing and again we are trying please everyone equally or, as my former supervisor said, equally unhappy if everyone is equally unhappy at the end of the tour selection process, then we have done our job.

You can see that all the tours have great coverage of the eyes of the southern hemisphere. I have evaluated the nominal tours that came out last week. Any modification is something we are going to have to deal with as a group this week. We can't have an input that is a mix of the two unless we all understand everything. the implications they debate it they listen to each other, sometimes it gets heated is that it's a reasonable approach, that's what I think I would like, but I have an objection to that, yes, are we making the right decision for the right reasons?

Well that's it. The team is going to have to think about that because we're not going to make the assignment until the tour is selected, so in a sense you're taking that risk. It can be very frustrating at first because in one meeting someone will tell you, "Let's do a you have to do a and in the next meeting they'll say oh, you can't do that, you have to do this instead, just a strategic comment. I think everyone in this room they know how rushed the judging of all these tours was because they came in so late it starts, everyone is on different ends, sometimes screaming, sometimes red-faced, really angry, like they're really trying to make sure get hurt.

The course designers have been looking at what the flexibility is on a given course to go up and down in altitude. You know we have to look at the ripple effect when you're high up in the orbital plane, you're way up and you start to get a good. view of the rings, but you are not around any of the other moons, so the people who want to look at the rings want to be up high and look at the rings, the other people want to be down on the same plane with the rings where they can visit all the other moons and that's a huge push and pull, you know? so that the j2 disturbances are not maximized.

What you are hearing here and I said it before. What are you hearing from people in this size of room? They haven't had a chance to really evaluate the information in a good enough way to think about. we made the right decision and I think we went through some stressful times at the beginning of the week, you know, meeting with each disciplined work group because you know we sat in front of these, you know, 40 or 50, you know, world-renowned scientists in a specific field and it's like a Congressional hearing where they just throw out questions, you know, one after another, you really have to know your stuff and understand every idiosyncrasy of each specific tour, but after they got hurt, I mean people like Calm Down a little bit, but eventually everyone gets fast, yeah, that's the best, so we're very lucky that the spaceship is very functional and we have a lot of fuel.

All the tours are good and I am happy if any of them. were selected, I mean they're all going to be really exciting, um, I mean, just, amazing photos, it's almost like we have Ansel Adams riding the spaceship, I'm talking about images, but I mean the other things are great. I also mean some of these instruments, they can just take a picture and they can tell you what it's made of, it's kind of a Star Trek thing, you know, but really Star Trek didn't have that cool of instruments, you know, they just had this . like the green lightning knee or you know, and he did everything right, his tricorder or whatever, or the really surprising thing is when they find something that's like they have no idea they have like a ipeto, that crest, what happens It's like the equator is really marked. like when I was a kid I had a globe that broke down and the equator was sticking out I mean that's how I have it it says there's a mountain ridge right along the equator it's so weird this meeting was just one of several What takes place is at this larger meeting where the tour designers' proposals representing a year's work with little free time for weekends and holidays will be judged compared to the usual agenda which today is upside down and the reason for this is the tour design. is the main topic of this entire meeting, you will notice that there is some filming or video going on.

This is a JPL activity to document howdecisions are made on the projects and, well, they have a cutting and editing process, so I'm. I'm not sure we'll necessarily recognize it when that's the case, it's like the worst final exam ever invented. You have 200 teachers you know and the hardest questions you can imagine and you're just working hard to solve them. it's done and then you hand it over uh pf7 11 they're both very similar to six and six h9 it feels good to have it handed to you, but you're not really awake enough for much emotion or anything from the nation, so you end up with a flyover of titan in apolapsus and uh or in periapsis and then you come back and you do a pie transfer and then you speed up again so there's a lot of lean time in this and when it comes to an infinite number of possibilities the runs are reduced to nine next , science teams must classify them as green acceptable, yellow partially acceptable, or red not acceptable, but it seems that six h9 and eight should be both red or both yellow, but they want more leeway. a new color for the lime vote, okay, uh 6h9, three greens, one lime and one red, uh, I mean, it's like our job is done, waiting to hear the result, I mean, I guess it's like the jury was coming, but you're too tired to care what your phrase is, so you're talking about pf9 for titan, a consensus is finally reached, no doubt, the winning tour has left the scientists equally happy and unhappy, the designers of the tour are simply happy for the first time in a year.

They'll get their lives back, that's it, it's over, the decision was made, you know, we were happy, but we also absolutely felt like your truck hit you. Hello, I'm Arthur Clark, joining you from my home in Colombo, Sri Lanka. I'm delighted to be part of it. of this event to mark the flyby of cassini in japanese when science fiction writer arthur c clarke wrote the classic 2001 a space odyssey which he chose for the final scene of the book saturn's moon iapetus as you know i have more than an interest passenger on Saturn in the 2001 film version the final scene was changed to Jupiter, but for Clark Iapeto remained a place of deep mystery, he shared his enthusiasm for Saturn's third largest moon with those who gathered in the JPL auditorium to witness the images of Iapeto when they first arrived.

This is a particularly exciting moment for fans of 2001 A Space Odyssey because this is where lone astronaut Dave Bowman discovers the Saturn monolith that turns out to be a gateway to the stars more than 40 years later. I don't remember why I linked Saturn to Antiopetus, but I've always had this strange fascination with Saturn and its family of moons because of the way that family has been growing at a very impressive rate. When Cassini launched, we only knew of 18 moons. , as I understand it. now there are 60 I'm counting I can't resist saying my god is full of moons so I'm going to keep my fingers crossed with what Cassini discovers in the apetus I want to thank everyone associated with this science mission The projects are tremendously important to our understanding of the solar system.

Who knows? One day our survival on Earth may depend on what we discover. This is Arthur Clark wishing you a successful flyby. What Cassini saw at Iapetus was impressive. Many of the observations focused on examining a mountain ridge at the equator that contributes to the moon's unusual nut-shaped appearance. These mountains made primarily of ice are among the tallest in the solar system with a height of 12 miles taller than double that of Mount Everest, scientists have more than one idea about how they may have formed a thought: perhaps when Iapetus was most fluid or flexible, it spun very, very fast, so it bulged at its equator as it spun and , when it cooled down, it kept that shape, it actually had that mountain. range surrounding it while the bulge has yet to be resolved, scientists believe they are on stronger ground as to why iapetus is so completely black and white.

One of the puzzles dating back to Voyager is that the dark material comes from within. iapetus maybe some kind of volcanic eruption or it comes from outside and cassini solved that puzzle it turns out there is a captured moon phoebe on the outer part of the saturn system phoebe dust enters and is blown to one side of the iapetus shell which side in an almost carbon black material this black material absorbs heat from the sun turning the moon's water ice into a vapor that accumulates as falling snow on the back side of iapetus the result is the distinctive yin and yang coating of the moon phoebe, the moon responsible for iapetus dark material resides on the outskirts of the saturnian system this is a frozen artifact from the time when the solar system was forming its battered surface speaks of a violent past everywhere there are ancient craters and landslides Earth Phoebe was the first Saturnian moon that Cassini saw up close and turned out to be a harbinger of the bounty to come, as at the time of Cassini's launch there were only 18 confirmed moons of Saturn, now there are 82 these moons are so diverse in shape , size and composition like numerous battered mimes with its enormous crater resembling The Death Star from Star Wars Hyperion resembles a sponge, its interior is full of voids to the point that it is considered more of a pile of rubble than a solid body atlas.

It could be confused with a UFO, Prometheus, a potato and a frying pan, a ravioli, these and other moons. They are part of the intricate Saturn system that influences the rings, the magnetosphere and even the planet and although it is best known for its rings, Saturn deserves its own attention, it is the second largest planet in the solar system by volume, Saturn could contain more than 700 composite lands. Composed mainly of helium and hydrogen gases, the planet has no solid surface, although inside it is believed to be a dense core of metals Despite its size, Saturn is surprisingly light, less dense than water, if it could be placed In an imaginary giant bathtub, Saturn would float.

The planet's spin speed is also impressive. Saturn's day lasts only ten and a half hours. This rapid rotation causes the planet to bulge at the equator and flatten at the poles. Saturn's candy-colored exterior appears smooth and calm, but this appearance is deceiving beneath cloud tops. It is a churning cauldron of lightning and winds with speeds that can reach over a thousand miles per hour, and approximately every 30 Earth years Saturn experiences a megastorm. Cassini had good timing to witness a raging storm that would grow to encircle the entire planet even further. amazing. is what can be seen at the poles of saturn saturn has something unique in the solar system it has a hexagon surrounding the north pole it is a six-sided jet stream you can almost imagine horses on a race track running around the hexagon we don't know why it maintains its six sided shape it is a kind of wave pattern that revolves around saturn but it is very stable it has been there for decades it is about two earth diameters wide in the center right at the north pole there is a giant hurricane it is about Half the size of the continental United States with wind speeds roughly four times the strength of a typical hurricane, a second monster storm was discovered at Saturn's south pole.

It is also surrounded by towering clouds, but it lacks a hexagon, and although this vortex looks like a hurricane, it does not behave. As one, these are just some of the wonders of Saturn witnessed by Cassini, but a completely different way to explore the planet is yet to come as the spacecraft nears completion for 2017. Cassini had circled Saturn more. 250 times and the mission's achievements had earned praise from many, including the first human being to set foot on another celestial body. Hello, I'm Neil Armstrong. We're here at the Cincinnati Observatory. Armstrong recorded this message to the Cassini team four years before his death.

It has been said that science is about what This and engineering is about what it can be Christina Huygens' program has demonstrated the best of both and you are the people who achieved the enormous success that it has been and are some of You are in the science of what is unraveling the secrets of Saturn. system has anyone had a full time job simply counting moons the number of their new discoveries is nothing short of astonishing some of you were in the category of what may be are involved in spacecraft design and trajectories design and operation of the system instrumentation how to make the measurements programming the computers we all give you our best wishes for continuing your excellent performance congratulations to each and every one of you Cassini's original lifetime warranty was four years on Saturn the mission doubled that warranty in 2017 20 years after its launch, the spacecraft was still performing beyond expectations.

It's like the spaceship just broke down. Everything works perfectly, but Cassini's days are numbered. It is running out of fuel and before that happens, the spacecraft must take a safe course. will not crash into one of Saturn's moons that could support life since Enceladus now appears to have all the ingredients that could support life. We have new rules and, frankly, we have a very nice home for microbes. The ambient temperature inside the spacecraft is a resistant microbe. We could have easily done it. We did a lot of studies on spacecraft disposal options. Some of them took it to very long and winding orbits of Saturn, where it would be stable for thousands of years, but there was no scientific benefit.

There we also had options to go back to Jupiter, go to Uranus, go to the Trojan asteroids, we could have exercised many of those options, but none of them had the strength and the appeal of a scientific mission to Saturn for which we were built. Saturn Saturn was absolutely full of things we hadn't yet explored. Once we decided to stay, we had to figure out how to get rid of the spaceship cleanly. It was decided to end the mission by plunging Cassini into Saturn, but not before attempting to dive 22 times. between the planet and the rings a place where no spacecraft has been right here is where Cassini is right now in its orbit Saturn is below the plane of the rings coming out here it will pass over the rings again in a few days we will This every seven and a half days, on April 22, the spacecraft will fly quite close to Saturn's large moon.

Titan and Titan has enough gravitation that we can use it to exchange orbital momentum between Titan orbiting Saturn and the spacecraft orbiting Saturn and with that exchange. -And something wonderful happens: the spacecraft's orbit jumps inward, toward Saturn, so the next close flyby of Saturn will be between Saturn's rings and atmosphere. It's so dangerous, we don't really know, but who knows, we might stumble upon something big. ring particles there that we can't see in our observations if that happens well it's been a good mission if it doesn't hit the spacecraft right away then we'll have 22 more flights up to a million miles it's a million mile roller coaster miles high, imagine clicking, clicking, clicking, clicking on a huge roller coaster and then it starts falling as we go through the space between the rings and the planet, we'll be going 120,000 kilometers per hour, most importantly.

I think it's the time when the Cassini signal reaches Earth, that means the spacecraft has passed, I don't know, maybe a thousand different commands spinning the spacecraft operating the cameras, the spectrometers, the dust detectors and the magnetometer, they make their observation. The spaceship continues to spin. and turning to signal everything and the moment the signal reaches the earth, we know that all that on the last day has been successful and I think it's party time, but before there can be party time, there is the less glamorous work of creating those commands and sometimes testing. them in hidden labs, I think we are ready to move on, this is another marine core, so after this meeting I will have to change this which is correct for 467. this is 444.

Okay, and this is not. It's not running in real time because it's synchronized with the actual spacecraft, so we'll end up sitting there so you have a reminder of when the first point is correct, so the first aacs command is at um 10 52 38 yeah yeah , this is The interesting thing that we are preparing is that we are practicing a main engine maneuver that we might need in the last weeks of the mission to exit the atmosphere or descend into the atmosphere, so we are really just simulating. about a meter per second burns the main engine, so the engine is going to burn for how many seconds, I'm not sure, actually four or fiveseconds, do you remember, Jody Joni, how long does the burn last on a meter six, okay, and what does the spaceship do? the spaceship always starts from the point on the earth and it does a turn and then it does a yaw and then you move and then you relax and you come back to the point on the earth and then you transmit all the data to the earth that we will be able to because we are in the integrated test lab, we will be able to see all the data in real time, so let's call it real time since we are practicing it.

What does swambo mean? It means she, who must always be there. obeyed you should take about 29 minutes so this is when it's your turn and they're shouting something right now system systems the roll the wine roll completed the spin the reaction wheels turned off oh yeah there it is up here let's go , hey attitude control yes you weren't listening I wasn't listening they said it tina tina called it tina I can't hear you I'm sorry you and musashi are going to have to talk you're going to have to develop your julie voice she was literally saying the words oh, I have what to announce when you said call recording status.

Now more than a month has passed, all the command tests are over and tonight the team members and their families and friends have gathered to see if Cassini will survive its first fall between the rings and Saturn. The event has been given a name. Gateway to the grand finale. Well, I just want to welcome everyone to our front door to the Cassini grand finale. This is a Cassini and I family event. I am very happy to see so many people here to share and what is about to happen tonight in 1990 linda spilker stood on this same stage talking about the rings of saturn the rings are more transitory elements of this three decades later she is the scientist of the Cassini project and the mistress of this night of ceremonies, so at midnight tonight will be the first time that Cassini returns to Earth and sends a signal and informs us that it successfully navigated through this gap where it first flew time, so we have a lot in store.

It will be very exciting as I wait for news at midnight, updates on the latest Cassini science discoveries are given, and a traditional JPL ritual is now recognized. I'm not particularly superstitious, but you know there's a long-standing JPL tradition, so last night I went out and decided we needed some lucky peanuts just in case and I thought about it some more and thought maybe we needed two jars of lucky peanuts. luck and with that I would like to introduce you to the virtual singers of Cassini, the real virtual singers. take the heart and soul of Cassini and capture it with music, so tonight live from JPL in Pasadena, California, just returning from their world tour, we now have the virtual Cassini singers flying over the seas towards me, while the Cassini singers take their bows.

Flight team members scurry to take their positions at the console in mission control. Flight and project director voice control. I would like to announce at this time that all stations are ready to provide support. Copy it, Copy it, thank you, okay? What we're looking at here is the mission support area and they each have their various stations that look at different aspects of the spacecraft and they just did a check to make sure everyone can hear everyone else on the msa and we also have sound in that room. Also, Eric, do you want to talk about what we're seeing on the screen here?

Yes, on the left is the signal that the deep space network is currently detecting, which is nothing, it's just a flat noise signal right now, but what we're going to be looking for here is for a spike to emerge. of that noise and when we see that peak it means that we are receiving a signal from Cassini, we have an expanded carrier signal detection and the open loop receiver which is a good signal booming so that the operator signal is there, we will have to wait a few minutes more until we see if there is actual data flowing in, but this is an excellent sign for a response.

Cassini's carrier tone means the spacecraft has survived. The first dive signal just arrived just in time. It could not have been better. Along with the sense of relief, we are hopeful that scientific data will soon begin to flow, but now comes a time of confusion about how to do it. better listen to the cassini signal esco systems cassini ace uh the station is currently searching for the x-span unidirectional carrier signal and they will also try to lock it to the 1896 speed so hold on I'll let you know if you understand, Asus is the director of flight, don't make them lock on 18996.

Okay, you just wanted to look for Cassini's aircraft carrier and range systems. The station has been set to the unidirectional X-band signal in neg 140 dB, which is expected by the year 1896 no copy exposed the moment of uncertainty ends as quickly as it began and Cassini begins transmitting its scientific data earlier than expected connector flight on the net well we're waiting for 1205 but it looks like we're early um well If there are any more questions, I'll be happy to answer them. I mean, this is the big moment we were waiting for and it's here and it's just as good as we expected.

We are good for 22 weeks. We're ok. now the spacecraft traversed the ring plane as cleanly as possible there are no failsafe indications the telemetry data playback is exactly where it's supposed to be we can all go home we don't have to spend all night fixing everything on the Acs spacecraft in perfect condition, go ahead, the downlink tour has begun at this time. We would like to inform you that all initial conditions have been reviewed. Initial attitude and wheel speeds look good. All instruments are on the star tracker. It's tracking five stars, so you can see both the sun well.

Sensors a and b are on so they match each other's telemetry at the moment, we are waiting for the role to give us full control of the quadrant for the rest of the way, other than acs looks great, director's copy of flight and project manager, this is the systems lead all subsystems have reported the inclusion of the sip leader at this time and everything is nominal congratulations everyone hello everyone I'm gay ye hill and welcome to the nasa jet propulsion laboratory After two decades in space NASA's Cassidy spacecraft came to the end of its extraordinary journey of exploration today, the spacecraft made its final approach to the giant planet and plunged into Saturn's upper atmosphere, ending this extraordinary mission, but due to the great distance between the Earth, the Cassini mission is not over yet, there is still a week left before the big final event. this is a rehearsal the sun hasn't risen yet and more than a hundred cassini scientists engineers alumni their friends and family have gathered here at mission control von carmen auditorium at jpl beckman auditorium in cal what's true for engineers So is JPL's public communications team.

A little pre-planning to troubleshoot can be worth its weight in gold. Australia It's 4:00 a.m. m. here in California the signal loss actually occurred at about 3:30 pacific time half an hour ago why is the team here? You'd be done, we'll get back to you in just a couple more minutes. There's a big crowd in Caltech's Beckman Auditorium right now. Cassini science team member Morgan Cable, is he there? Morgan, what's the situation like out there? Hi gay, I'm Morgan. at Caltech and the atmosphere is electric, I think we are going to have a limit and I am one of those who expect Cassini to hold on and fight for the last few seconds of data.

What's going on? Well, we just found out. that cassini has given us its latest data the room is celebrating many hugs and some tears with me now i am the director of planetary science at nasa jim green jim thanks for joining us, you know gay, this really has been a historic mission before we do it, Let's take a moment to chat with JPL Director Mike Watkins, what's your feeling about the success of the Cassini mission? You know, I couldn't be more proud of the role we've played in this mission with me now being Alvaro Giménez the the director of that and the director of science Roberto Uh Issa Director of Sciences Roberto Battiston Batistan Batista but, joking aside, the planning paid off. because the elaborate multimedia and interactive coverage of cassini's grand finale would be seen by millions and the emmy goes to nasa jpl cassini's grand finale ends and wins JPL its first Emmy.

I have to thank the stars who turned a bunch of geeky rocket scientists, rocket engineers and scientists into Indus rock stars. Here is Huygens' image of the um gullies. There is less than a week until the end of Cassini and team members from around the world are arriving to participate in the grand finale this is the final meeting of the scientific radar group we have actually been at this for 40 years this is a picture from 1976 is one of bruce murray's purple dove projects and this is what became the The Huygens probe transmits the data to Cassini, which is flying so far in time and I want to give a warning, since they are found a billion miles away.

Cassini is flying at Titan for the last time right now. Cassini is flying close to Titan at 74,000 miles. far away and titan's gravity has given cassini its final push it's a kiss goodbye and its fate is sealed and we toast the great spacecraft a wonderful mission and our final passage through the titans i worked on the cassini mission for more than 30 years and that's how long it takes for Saturn to go around the sun just once and when you work on a mission for that long and when you work for people, many of whom stayed and were there as long as I did, you really start to feel like a family, you know each other, you take vacations together, you attend meetings together, you watch your families grow together and then when the mission is over, it's hard because you know you're going to stay in touch with this family, these people who feel like friends and, However, you also know that you will go. their separate ways, so for the people who have been with the team since the beginning, thank you and I hope you found this.

They are now 30 years wiser and smarter and this has been a great experience, but for the people who joined later, I hope they found that. It's also a great springboard and experience for you guys to lead the future of planetary exploration, so thanks again for the cookies. The next day, Cassini engineers will gather for their final in-flight operations meeting. 5502 is when we predict we will reach duty cycle 100 and aacs predicts signal loss 12 seconds after that duane navigation yesterday around 1:30 pm we had our last eye of titan 5 and now we are on our way to saturn dsn mike so we had seven passes last week 14 command files um including the latest build set so we don't have any more real time commands that's 101.

Well the spaceship is basically nominal we don't have any new isas no other errors and then we basically have the end of the sequence. Coming out here we know that this is the end, it's very sad, but knowing that on a mission like Cassini we had an end date, we had a sequence of events to follow, it gave us some purpose, all the teams stepped up, I am very grateful. for all your support and I just want to say thank you, does anyone else have anything? uh yeah, just because everyone else has kept saying thank you, uh, you here in the room and on the phone, you've rocked the world and this is our last meeting with a spaceship, uh, but it's been a trip incredible.

I am very, very proud to have been associated with all of you. And as an incentive for the next meeting, when we don't have a spaceship, we'll bring donuts, thank you all. it's two hours two hours two hours ago yeah it's now 2 55 in the morning in california we have about two hours left until the end the science data from the recorders is ready we're currently in our real time dive setup um so everything now It's essentially real time data from the instruments as we enter the planet, the ffts will start to fade in and out and then at a single point they will just disappear completely and that will be there.

In the end, it is very difficult to finish the mission this way. This has been my constant companion for 22 years. My job has always been to take care of the spaceship. Everything works perfectly. I mean, you have to acknowledge the fact that we're out of thrusters. but I have no idea how I'm going to feel okay look this is my screen up here so this screen here is the last 10 minutes of the one up here the one up there is kind of a big picture and this one It has a modeled atmosphere, this is also the last 10 minutes, but this one does not have a modeled atmosphere, so what we are going to do is what we expect to see when we get to the end and enter the atmosphere, this is going to start. being different from this in thismoment, they look very similar once this starts to change from this, then we know that we are in the atmosphere and we are experiencing drag on the spacecraft about a minute before the signal is lost, the other squat that we have overcome I the attitude control system, those graphs on the right of that screen show the activity of the thrusters and we're going to see them go up the wall, so to speak, and again for about a minute, I mean, it all happens very quickly, does it?

TRUE? Okay, so what we're looking at is each of these little places where the curve turns is where the thrusters activate. We are trying to control the orientation of the spacecraft and every time we see a small change in direction, that is a pulse from the thruster and those pulses are becoming more frequent and the reason for this is that we are getting closer to Saturn and its Gravity gradient is starting to spin the spacecraft around which will happen eventually, instead of slowly balancing along the edge and it will just be sitting right on the edge firing the thrusters continuously until the point where the thrusters are fully fired. and I can no longer maintain that attitude and then we will just walk out of our thresholds and then We will be wandering around, that will be the end, when do we want to break the ceremonial anomaly plan?

If you think of Cassini as a symphony, this is the last final movement, there are so many emotions, I mean, it's such a sweet and wonderful journey, it's been like that. It has been a triumph We are a people It has been phenomenal teamwork We finished each other's sentences We tied our shoes It is definitely going to be something that I will never be able to recreate and I will miss it very much among those who arrive. Mike Watkins just now wasn't always 5 a.m. m. a couple of hours a little watkins has been leading jpl for a year the fourth director of jpl cassini has seen hello everyone I'm gay ye hill and welcome to nasa's jet propulsion laboratory decades in space the spacecraft made its final approach to the giant planet meanwhile it's 4 a.m.

Here in California the sun hasn't risen yet and more than 1,500 Cassini scientists, engineers, alumni, friends and family have gathered for this moment, how does it feel to Todd to be here? Hello gay. Well, it's great to be back while you and I were sitting there in 2004. We never dreamed we'd be here in 2017, still talking about Cassini and collecting science data, so I'm delighted to be here, even having aged a few years since then. league of flight director systems forward all subsystems are nominal let's go for the spacecraft just crossed 40 degrees north latitude thanks the trajectory is the most recent trajectory that we have reconstructed with the latest data that we could obtain, so that little point here that's cassini so that's pretty accurate and yeah that's cool the systems mission planning lead spacecraft just crossed 30 degrees north latitude altitude is 6000 miles thanks miles yeah , finally shouting miles, that's where well, we're just over 10 minutes away from signal loss, so we'll turn our attention to the control room very soon, but before we do, let's take a moment to chat with the director of JPL, Mike Watkins, so Mike, how are you feeling okay?

First, good morning, yes, very early, we always tend to do these events. somehow at three in the morning or five in the morning it does, but you know, it's a bittersweet event for all of us. I think for me personally it's sweeter than better because Cassini has been a fantastic mission, but I think you know. One of the important things about these events is to celebrate the incredible hard work, the decades of hard work of the team that designed, built and operated Cassini and that's really true, the heart of the spacecraft is really the people who worked on it and the people I've been operating it and this is a good time to celebrate that level of dedication, that devotion, you know, working on something for 10, 20, 30 years, something that has no parallel in the systems of human history, this It's acs-1, we're still waiting for a transition to high speed mode, but it looks like we're going to start accumulating propellant on time, at a higher speed now and our attitude control bug is starting to become more active, okay, and we're in the atmosphere, oh. yeah what you're really challenging we have a lot of signal that really benefits your event project manager flight director go ahead okay we call signal loss one one five five four six for s band so that it would be the end of the spacecraft project manager.

About the fso agreement I hope you are all deeply proud of this incredible achievement, congratulations everyone, this has been an incredible mission, an incredible spacecraft and you are all an incredible team. I'm going to call this the end-of-mission project manager. off the grid four three three five and seven four my feeling was that I wanted to hug someone and share say goodbye and that was difficult it was difficult to say goodbye manager program manager is confirmed on a mission in one one five five four six uh this concludes the thirteen years of cassiniexploring the saturn system the looks you see on people's faces we are not acting we feel like you are looking at a raw emotion at that moment I thought it was going to be okay and it wasn't, we did it and it worked but now finished what has been so long, yes, let's do another one every time we lead, this is acs acs, go ahead, the post, burn, unroll, spin, spin, it's a complete copy, thanks to fso, quartz flight director, Go ahead, yes you can go ahead and verify people outside the network.

Let everyone here on the network know and we'll discuss what we need to do, including what's happening with the dtus. Okay, copy, I got it. Thank you. Manu thinks this is a thermal terminal. Forward, the thermal devices subsystem is nominal after the maneuver requesting permission. to get off the net copy sounds good thanks for your support copy tom go ahead yes I would like to report that the telecoms are nominal the subsystem is nominal and the Doppler and telemetry look good so we would request close the network copy. well, thanks for your cds support, go ahead, yes, we know that the cds system is nominal at this time and we would like to go offline. okay, copy, thanks for your support.

Might is the means and I would like to request permission. to exit the networks copy thank you electrical maneuvering cable system total protection sfp forward I can confirm that there is no fall protection activity and all telemetry is as predicted as of page 10 in the procedure and ssp would like permission to exit from the net ok copy thanks final The status of the ltm on the outside is about once a request disabled to sing okay copy thanks the commands in the maneuver and I've done my final inquiries and it looks like a nominal burn so I request permission to log out. net ok copy thanks for your support could you relate to the prop go ahead the recording time was achieved in about half a second so it looks like a good rcs recording regarding the prop maneuver in the episode , yes, at this time, all subsystems have reported a nominal write for otm 469, so I will log out as main copy of systems, thank you, thank you